net: ip_tunnel: make sure to pull inner header in ip_tunnel_rcv()

Apply the same fix than ones found in :

8d975c15c0cd ("ip6_tunnel: make sure to pull inner header in __ip6_tnl_rcv()")
1ca1ba465e55 ("geneve: make sure to pull inner header in geneve_rx()")

We have to save skb->network_header in a temporary variable
in order to be able to recompute the network_header pointer
after a pskb_inet_may_pull() call.

pskb_inet_may_pull() makes sure the needed headers are in skb->head.

syzbot reported:
BUG: KMSAN: uninit-value in __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline]
BUG: KMSAN: uninit-value in INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline]
BUG: KMSAN: uninit-value in IP_ECN_decapsulate include/net/inet_ecn.h:302 [inline]
BUG: KMSAN: uninit-value in ip_tunnel_rcv+0xed9/0x2ed0 net/ipv4/ip_tunnel.c:409
__INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline]
INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline]
IP_ECN_decapsulate include/net/inet_ecn.h:302 [inline]
ip_tunnel_rcv+0xed9/0x2ed0 net/ipv4/ip_tunnel.c:409
__ipgre_rcv+0x9bc/0xbc0 net/ipv4/ip_gre.c:389
ipgre_rcv net/ipv4/ip_gre.c:411 [inline]
gre_rcv+0x423/0x19f0 net/ipv4/ip_gre.c:447
gre_rcv+0x2a4/0x390 net/ipv4/gre_demux.c:163
ip_protocol_deliver_rcu+0x264/0x1300 net/ipv4/ip_input.c:205
ip_local_deliver_finish+0x2b8/0x440 net/ipv4/ip_input.c:233
NF_HOOK include/linux/netfilter.h:314 [inline]
ip_local_deliver+0x21f/0x490 net/ipv4/ip_input.c:254
dst_input include/net/dst.h:461 [inline]
ip_rcv_finish net/ipv4/ip_input.c:449 [inline]
NF_HOOK include/linux/netfilter.h:314 [inline]
ip_rcv+0x46f/0x760 net/ipv4/ip_input.c:569
__netif_receive_skb_one_core net/core/dev.c:5534 [inline]
__netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5648
netif_receive_skb_internal net/core/dev.c:5734 [inline]
netif_receive_skb+0x58/0x660 net/core/dev.c:5793
tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1556
tun_get_user+0x53b9/0x66e0 drivers/net/tun.c:2009
tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2055
call_write_iter include/linux/fs.h:2087 [inline]
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0xb6b/0x1520 fs/read_write.c:590
ksys_write+0x20f/0x4c0 fs/read_write.c:643
__do_sys_write fs/read_write.c:655 [inline]
__se_sys_write fs/read_write.c:652 [inline]
__x64_sys_write+0x93/0xd0 fs/read_write.c:652
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
__alloc_pages+0x9a6/0xe00 mm/page_alloc.c:4590
alloc_pages_mpol+0x62b/0x9d0 mm/mempolicy.c:2133
alloc_pages+0x1be/0x1e0 mm/mempolicy.c:2204
skb_page_frag_refill+0x2bf/0x7c0 net/core/sock.c:2909
tun_build_skb drivers/net/tun.c:1686 [inline]
tun_get_user+0xe0a/0x66e0 drivers/net/tun.c:1826
tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2055
call_write_iter include/linux/fs.h:2087 [inline]
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0xb6b/0x1520 fs/read_write.c:590
ksys_write+0x20f/0x4c0 fs/read_write.c:643
__do_sys_write fs/read_write.c:655 [inline]
__se_sys_write fs/read_write.c:652 [inline]
__x64_sys_write+0x93/0xd0 fs/read_write.c:652
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: annotate data-races around t->parms.link

t->parms.link is read locklessly, annotate these reads
and opposite writes accordingly.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: add netdev_lockdep_set_classes() to virtual drivers

Based on a syzbot report, it appears many virtual
drivers do not yet use netdev_lockdep_set_classes(),
triggerring lockdep false positives.

WARNING: possible recursive locking detected
6.8.0-rc4-next-20240212-syzkaller #0 Not tainted

syz-executor.0/19016 is trying to acquire lock:
ffff8880162cb298 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff8880162cb298 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4452 [inline]
ffff8880162cb298 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x1c4/0x5f0 net/sched/sch_generic.c:340

but task is already holding lock:
ffff8880223db4d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff8880223db4d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4452 [inline]
ffff8880223db4d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x1c4/0x5f0 net/sched/sch_generic.c:340

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
lock(_xmit_ETHER#2);
lock(_xmit_ETHER#2);

*** DEADLOCK ***

May be due to missing lock nesting notation

9 locks held by syz-executor.0/19016:
#0: ffffffff8f385208 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
#0: ffffffff8f385208 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x82c/0x1040 net/core/rtnetlink.c:6603
#1: ffffc90000a08c00 ((&in_dev->mr_ifc_timer)){+.-.}-{0:0}, at: call_timer_fn+0xc0/0x600 kernel/time/timer.c:1697
#2: ffffffff8e131520 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
#2: ffffffff8e131520 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
#2: ffffffff8e131520 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x45f/0x1360 net/ipv4/ip_output.c:228
#3: ffffffff8e131580 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#3: ffffffff8e131580 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:802 [inline]
#3: ffffffff8e131580 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c4/0x3b10 net/core/dev.c:4284
#4: ffff8880416e3258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline]
#4: ffff8880416e3258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline]
#4: ffff8880416e3258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3771 [inline]
#4: ffff8880416e3258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x1262/0x3b10 net/core/dev.c:4325
#5: ffff8880223db4d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
#5: ffff8880223db4d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4452 [inline]
#5: ffff8880223db4d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x1c4/0x5f0 net/sched/sch_generic.c:340
#6: ffffffff8e131520 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
#6: ffffffff8e131520 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
#6: ffffffff8e131520 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x45f/0x1360 net/ipv4/ip_output.c:228
#7: ffffffff8e131580 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#7: ffffffff8e131580 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:802 [inline]
#7: ffffffff8e131580 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c4/0x3b10 net/core/dev.c:4284
#8: ffff888014d9d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline]
#8: ffff888014d9d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline]
#8: ffff888014d9d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3771 [inline]
#8: ffff888014d9d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x1262/0x3b10 net/core/dev.c:4325

stack backtrace:
CPU: 1 PID: 19016 Comm: syz-executor.0 Not tainted 6.8.0-rc4-next-20240212-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
check_deadlock kernel/locking/lockdep.c:3062 [inline]
validate_chain+0x15c1/0x58e0 kernel/locking/lockdep.c:3856
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
__netif_tx_lock include/linux/netdevice.h:4452 [inline]
sch_direct_xmit+0x1c4/0x5f0 net/sched/sch_generic.c:340
__dev_xmit_skb net/core/dev.c:3784 [inline]
__dev_queue_xmit+0x1912/0x3b10 net/core/dev.c:4325
neigh_output include/net/neighbour.h:542 [inline]
ip_finish_output2+0xe66/0x1360 net/ipv4/ip_output.c:235
iptunnel_xmit+0x540/0x9b0 net/ipv4/ip_tunnel_core.c:82
ip_tunnel_xmit+0x20ee/0x2960 net/ipv4/ip_tunnel.c:831
erspan_xmit+0x9de/0x1460 net/ipv4/ip_gre.c:720
__netdev_start_xmit include/linux/netdevice.h:4989 [inline]
netdev_start_xmit include/linux/netdevice.h:5003 [inline]
xmit_one net/core/dev.c:3555 [inline]
dev_hard_start_xmit+0x242/0x770 net/core/dev.c:3571
sch_direct_xmit+0x2b6/0x5f0 net/sched/sch_generic.c:342
__dev_xmit_skb net/core/dev.c:3784 [inline]
__dev_queue_xmit+0x1912/0x3b10 net/core/dev.c:4325
neigh_output include/net/neighbour.h:542 [inline]
ip_finish_output2+0xe66/0x1360 net/ipv4/ip_output.c:235
igmpv3_send_cr net/ipv4/igmp.c:723 [inline]
igmp_ifc_timer_expire+0xb71/0xd90 net/ipv4/igmp.c:813
call_timer_fn+0x17e/0x600 kernel/time/timer.c:1700
expire_timers kernel/time/timer.c:1751 [inline]
__run_timers+0x621/0x830 kernel/time/timer.c:2038
run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2051
__do_softirq+0x2bc/0x943 kernel/softirq.c:554
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633
irq_exit_rcu+0x9/0x30 kernel/softirq.c:645
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1076 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1076
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:resched_offsets_ok kernel/sched/core.c:10127 [inline]
RIP: 0010:__might_resched+0x16f/0x780 kernel/sched/core.c:10142
Code: 00 4c 89 e8 48 c1 e8 03 48 ba 00 00 00 00 00 fc ff df 48 89 44 24 38 0f b6 04 10 84 c0 0f 85 87 04 00 00 41 8b 45 00 c1 e0 08 <01> d8 44 39 e0 0f 85 d6 00 00 00 44 89 64 24 1c 48 8d bc 24 a0 00
RSP: 0018:ffffc9000ee069e0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff8880296a9e00
RDX: dffffc0000000000 RSI: ffff8880296a9e00 RDI: ffffffff8bfe8fa0
RBP: ffffc9000ee06b00 R08: ffffffff82326877 R09: 1ffff11002b5ad1b
R10: dffffc0000000000 R11: ffffed1002b5ad1c R12: 0000000000000000
R13: ffff8880296aa23c R14: 000000000000062a R15: 1ffff92001dc0d44
down_write+0x19/0x50 kernel/locking/rwsem.c:1578
kernfs_activate fs/kernfs/dir.c:1403 [inline]
kernfs_add_one+0x4af/0x8b0 fs/kernfs/dir.c:819
__kernfs_create_file+0x22e/0x2e0 fs/kernfs/file.c:1056
sysfs_add_file_mode_ns+0x24a/0x310 fs/sysfs/file.c:307
create_files fs/sysfs/group.c:64 [inline]
internal_create_group+0x4f4/0xf20 fs/sysfs/group.c:152
internal_create_groups fs/sysfs/group.c:192 [inline]
sysfs_create_groups+0x56/0x120 fs/sysfs/group.c:218
create_dir lib/kobject.c:78 [inline]
kobject_add_internal+0x472/0x8d0 lib/kobject.c:240
kobject_add_varg lib/kobject.c:374 [inline]
kobject_init_and_add+0x124/0x190 lib/kobject.c:457
netdev_queue_add_kobject net/core/net-sysfs.c:1706 [inline]
netdev_queue_update_kobjects+0x1f3/0x480 net/core/net-sysfs.c:1758
register_queue_kobjects net/core/net-sysfs.c:1819 [inline]
netdev_register_kobject+0x265/0x310 net/core/net-sysfs.c:2059
register_netdevice+0x1191/0x19c0 net/core/dev.c:10298
bond_newlink+0x3b/0x90 drivers/net/bonding/bond_netlink.c:576
rtnl_newlink_create net/core/rtnetlink.c:3506 [inline]
__rtnl_newlink net/core/rtnetlink.c:3726 [inline]
rtnl_newlink+0x158f/0x20a0 net/core/rtnetlink.c:3739
rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6606
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543
netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367
netlink_sendmsg+0xa3c/0xd70 net/netlink/af_netlink.c:1908
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745
__sys_sendto+0x3a4/0x4f0 net/socket.c:2191
__do_sys_sendto net/socket.c:2203 [inline]
__se_sys_sendto net/socket.c:2199 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2199
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7fc3fa87fa9c

Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240212140700.2795436-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ip_tunnel: use exit_batch_rtnl() method

exit_batch_rtnl() is called while RTNL is held,
and devices to be unregistered can be queued in the dev_kill_list.

This saves one rtnl_lock()/rtnl_unlock() pair
and one unregister_netdevice_many() call.

This patch takes care of ipip, ip_vti, and ip_gre tunnels.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Antoine Tenart <atenart@kernel.org>
Link: https://lore.kernel.org/r/20240206144313.2050392-15-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ip_tunnel: prevent perpetual headroom growth

syzkaller triggered following kasan splat:
BUG: KASAN: use-after-free in __skb_flow_dissect+0x19d1/0x7a50 net/core/flow_dissector.c:1170
Read of size 1 at addr ffff88812fb4000e by task syz-executor183/5191
[..]
kasan_report+0xda/0x110 mm/kasan/report.c:588
__skb_flow_dissect+0x19d1/0x7a50 net/core/flow_dissector.c:1170
skb_flow_dissect_flow_keys include/linux/skbuff.h:1514 [inline]
___skb_get_hash net/core/flow_dissector.c:1791 [inline]
__skb_get_hash+0xc7/0x540 net/core/flow_dissector.c:1856
skb_get_hash include/linux/skbuff.h:1556 [inline]
ip_tunnel_xmit+0x1855/0x33c0 net/ipv4/ip_tunnel.c:748
ipip_tunnel_xmit+0x3cc/0x4e0 net/ipv4/ipip.c:308
__netdev_start_xmit include/linux/netdevice.h:4940 [inline]
netdev_start_xmit include/linux/netdevice.h:4954 [inline]
xmit_one net/core/dev.c:3548 [inline]
dev_hard_start_xmit+0x13d/0x6d0 net/core/dev.c:3564
__dev_queue_xmit+0x7c1/0x3d60 net/core/dev.c:4349
dev_queue_xmit include/linux/netdevice.h:3134 [inline]
neigh_connected_output+0x42c/0x5d0 net/core/neighbour.c:1592
...
ip_finish_output2+0x833/0x2550 net/ipv4/ip_output.c:235
ip_finish_output+0x31/0x310 net/ipv4/ip_output.c:323
..
iptunnel_xmit+0x5b4/0x9b0 net/ipv4/ip_tunnel_core.c:82
ip_tunnel_xmit+0x1dbc/0x33c0 net/ipv4/ip_tunnel.c:831
ipgre_xmit+0x4a1/0x980 net/ipv4/ip_gre.c:665
__netdev_start_xmit include/linux/netdevice.h:4940 [inline]
netdev_start_xmit include/linux/netdevice.h:4954 [inline]
xmit_one net/core/dev.c:3548 [inline]
dev_hard_start_xmit+0x13d/0x6d0 net/core/dev.c:3564
...

The splat occurs because skb->data points past skb->head allocated area.
This is because neigh layer does:
__skb_pull(skb, skb_network_offset(skb));

... but skb_network_offset() returns a negative offset and __skb_pull()
arg is unsigned. IOW, we skb->data gets "adjusted" by a huge value.

The negative value is returned because skb->head and skb->data distance is
more than 64k and skb->network_header (u16) has wrapped around.

The bug is in the ip_tunnel infrastructure, which can cause
dev->needed_headroom to increment ad infinitum.

The syzkaller reproducer consists of packets getting routed via a gre
tunnel, and route of gre encapsulated packets pointing at another (ipip)
tunnel. The ipip encapsulation finds gre0 as next output device.

This results in the following pattern:

1). First packet is to be sent out via gre0.
Route lookup found an output device, ipip0.

2).
ip_tunnel_xmit for gre0 bumps gre0->needed_headroom based on the future
output device, rt.dev->needed_headroom (ipip0).

3).
ip output / start_xmit moves skb on to ipip0. which runs the same
code path again (xmit recursion).

4).
Routing step for the post-gre0-encap packet finds gre0 as output device
to use for ipip0 encapsulated packet.

tunl0->needed_headroom is then incremented based on the (already bumped)
gre0 device headroom.

This repeats for every future packet:

gre0->needed_headroom gets inflated because previous packets' ipip0 step
incremented rt->dev (gre0) headroom, and ipip0 incremented because gre0
needed_headroom was increased.

For each subsequent packet, gre/ipip0->needed_headroom grows until
post-expand-head reallocations result in a skb->head/data distance of
more than 64k.

Once that happens, skb->network_header (u16) wraps around when
pskb_expand_head tries to make sure that skb_network_offset() is unchanged
after the headroom expansion/reallocation.

After this skb_network_offset(skb) returns a different (and negative)
result post headroom expansion.

The next trip to neigh layer (or anything else that would __skb_pull the
network header) makes skb->data point to a memory location outside
skb->head area.

v2: Cap the needed_headroom update to an arbitarily chosen upperlimit to
prevent perpetual increase instead of dropping the headroom increment
completely.

Reported-and-tested-by: syzbot+bfde3bef047a81b8fde6@syzkaller.appspotmail.com
Closes: https://groups.google.com/g/syzkaller-bugs/c/fL9G6GtWskY/m/VKk_PR5FBAAJ
Fixes: 243aad830e8a ("ip_gre: include route header_len in max_headroom calculation")
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240220135606.4939-1-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: fill in MODULE_DESCRIPTION()s for ipv4 modules

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the IPv4 modules.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240208164244.3818498-7-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip devices

Today ipip devices in collect-metadata mode don't allow for sending FOU
or GUE encapsulated packets. This patch lifts the restriction by adding
a struct ip_tunnel_encap to the tunnel metadata.

On the egress path, the members of this struct can be set by the
bpf_skb_set_fou_encap kfunc via a BPF tc-hook. Instead of dropping packets
wishing to use additional UDP encapsulation, ip_md_tunnel_xmit now
evaluates the contents of this struct and adds the corresponding FOU or
GUE header. Furthermore, it is making sure that additional header bytes
are taken into account for PMTU discovery.

On the ingress path, an ipip device in collect-metadata mode will fill this
struct and a BPF tc-hook can obtain the information via a call to the
bpf_skb_get_fou_encap kfunc.

The minor change to ip_tunnel_encap, which now takes a pointer to
struct ip_tunnel_encap instead of struct ip_tunnel, allows us to control
FOU encap type and parameters on a per packet-level.

Signed-off-by: Christian Ehrig <cehrig@cloudflare.com>
Link: https://lore.kernel.org/r/cfea47de655d0f870248abf725932f851b53960a.1680874078.git.cehrig@cloudflare.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

net: tunnels: annotate lockless accesses to dev->needed_headroom

IP tunnels can apparently update dev->needed_headroom
in their xmit path.

This patch takes care of three tunnels xmit, and also the
core LL_RESERVED_SPACE() and LL_RESERVED_SPACE_EXTRA()
helpers.

More changes might be needed for completeness.

BUG: KCSAN: data-race in ip_tunnel_xmit / ip_tunnel_xmit

read to 0xffff88815b9da0ec of 2 bytes by task 888 on cpu 1:
ip_tunnel_xmit+0x1270/0x1730 net/ipv4/ip_tunnel.c:803
__gre_xmit net/ipv4/ip_gre.c:469 [inline]
ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:661
__netdev_start_xmit include/linux/netdevice.h:4881 [inline]
netdev_start_xmit include/linux/netdevice.h:4895 [inline]
xmit_one net/core/dev.c:3580 [inline]
dev_hard_start_xmit+0x127/0x400 net/core/dev.c:3596
__dev_queue_xmit+0x1007/0x1eb0 net/core/dev.c:4246
dev_queue_xmit include/linux/netdevice.h:3051 [inline]
neigh_direct_output+0x17/0x20 net/core/neighbour.c:1623
neigh_output include/net/neighbour.h:546 [inline]
ip_finish_output2+0x740/0x840 net/ipv4/ip_output.c:228
ip_finish_output+0xf4/0x240 net/ipv4/ip_output.c:316
NF_HOOK_COND include/linux/netfilter.h:291 [inline]
ip_output+0xe5/0x1b0 net/ipv4/ip_output.c:430
dst_output include/net/dst.h:444 [inline]
ip_local_out+0x64/0x80 net/ipv4/ip_output.c:126
iptunnel_xmit+0x34a/0x4b0 net/ipv4/ip_tunnel_core.c:82
ip_tunnel_xmit+0x1451/0x1730 net/ipv4/ip_tunnel.c:813
__gre_xmit net/ipv4/ip_gre.c:469 [inline]
ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:661
__netdev_start_xmit include/linux/netdevice.h:4881 [inline]
netdev_start_xmit include/linux/netdevice.h:4895 [inline]
xmit_one net/core/dev.c:3580 [inline]
dev_hard_start_xmit+0x127/0x400 net/core/dev.c:3596
__dev_queue_xmit+0x1007/0x1eb0 net/core/dev.c:4246
dev_queue_xmit include/linux/netdevice.h:3051 [inline]
neigh_direct_output+0x17/0x20 net/core/neighbour.c:1623
neigh_output include/net/neighbour.h:546 [inline]
ip_finish_output2+0x740/0x840 net/ipv4/ip_output.c:228
ip_finish_output+0xf4/0x240 net/ipv4/ip_output.c:316
NF_HOOK_COND include/linux/netfilter.h:291 [inline]
ip_output+0xe5/0x1b0 net/ipv4/ip_output.c:430
dst_output include/net/dst.h:444 [inline]
ip_local_out+0x64/0x80 net/ipv4/ip_output.c:126
iptunnel_xmit+0x34a/0x4b0 net/ipv4/ip_tunnel_core.c:82
ip_tunnel_xmit+0x1451/0x1730 net/ipv4/ip_tunnel.c:813
__gre_xmit net/ipv4/ip_gre.c:469 [inline]
ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:661
__netdev_start_xmit include/linux/netdevice.h:4881 [inline]
netdev_start_xmit include/linux/netdevice.h:4895 [inline]
xmit_one net/core/dev.c:3580 [inline]
dev_hard_start_xmit+0x127/0x400 net/core/dev.c:3596
__dev_queue_xmit+0x1007/0x1eb0 net/core/dev.c:4246
dev_queue_xmit include/linux/netdevice.h:3051 [inline]
neigh_direct_output+0x17/0x20 net/core/neighbour.c:1623
neigh_output include/net/neighbour.h:546 [inline]
ip_finish_output2+0x740/0x840 net/ipv4/ip_output.c:228
ip_finish_output+0xf4/0x240 net/ipv4/ip_output.c:316
NF_HOOK_COND include/linux/netfilter.h:291 [inline]
ip_output+0xe5/0x1b0 net/ipv4/ip_output.c:430
dst_output include/net/dst.h:444 [inline]
ip_local_out+0x64/0x80 net/ipv4/ip_output.c:126
iptunnel_xmit+0x34a/0x4b0 net/ipv4/ip_tunnel_core.c:82
ip_tunnel_xmit+0x1451/0x1730 net/ipv4/ip_tunnel.c:813
__gre_xmit net/ipv4/ip_gre.c:469 [inline]
ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:661
__netdev_start_xmit include/linux/netdevice.h:4881 [inline]
netdev_start_xmit include/linux/netdevice.h:4895 [inline]
xmit_one net/core/dev.c:3580 [inline]
dev_hard_start_xmit+0x127/0x400 net/core/dev.c:3596
__dev_queue_xmit+0x1007/0x1eb0 net/core/dev.c:4246
dev_queue_xmit include/linux/netdevice.h:3051 [inline]
neigh_direct_output+0x17/0x20 net/core/neighbour.c:1623
neigh_output include/net/neighbour.h:546 [inline]
ip_finish_output2+0x740/0x840 net/ipv4/ip_output.c:228
ip_finish_output+0xf4/0x240 net/ipv4/ip_output.c:316
NF_HOOK_COND include/linux/netfilter.h:291 [inline]
ip_output+0xe5/0x1b0 net/ipv4/ip_output.c:430
dst_output include/net/dst.h:444 [inline]
ip_local_out+0x64/0x80 net/ipv4/ip_output.c:126
iptunnel_xmit+0x34a/0x4b0 net/ipv4/ip_tunnel_core.c:82
ip_tunnel_xmit+0x1451/0x1730 net/ipv4/ip_tunnel.c:813
__gre_xmit net/ipv4/ip_gre.c:469 [inline]
ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:661
__netdev_start_xmit include/linux/netdevice.h:4881 [inline]
netdev_start_xmit include/linux/netdevice.h:4895 [inline]
xmit_one net/core/dev.c:3580 [inline]
dev_hard_start_xmit+0x127/0x400 net/core/dev.c:3596
__dev_queue_xmit+0x1007/0x1eb0 net/core/dev.c:4246
dev_queue_xmit include/linux/netdevice.h:3051 [inline]
neigh_direct_output+0x17/0x20 net/core/neighbour.c:1623
neigh_output include/net/neighbour.h:546 [inline]
ip_finish_output2+0x740/0x840 net/ipv4/ip_output.c:228
ip_finish_output+0xf4/0x240 net/ipv4/ip_output.c:316
NF_HOOK_COND include/linux/netfilter.h:291 [inline]
ip_output+0xe5/0x1b0 net/ipv4/ip_output.c:430
dst_output include/net/dst.h:444 [inline]
ip_local_out+0x64/0x80 net/ipv4/ip_output.c:126
iptunnel_xmit+0x34a/0x4b0 net/ipv4/ip_tunnel_core.c:82
ip_tunnel_xmit+0x1451/0x1730 net/ipv4/ip_tunnel.c:813
__gre_xmit net/ipv4/ip_gre.c:469 [inline]
ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:661
__netdev_start_xmit include/linux/netdevice.h:4881 [inline]
netdev_start_xmit include/linux/netdevice.h:4895 [inline]
xmit_one net/core/dev.c:3580 [inline]
dev_hard_start_xmit+0x127/0x400 net/core/dev.c:3596
__dev_queue_xmit+0x1007/0x1eb0 net/core/dev.c:4246
dev_queue_xmit include/linux/netdevice.h:3051 [inline]
neigh_direct_output+0x17/0x20 net/core/neighbour.c:1623
neigh_output include/net/neighbour.h:546 [inline]
ip_finish_output2+0x740/0x840 net/ipv4/ip_output.c:228
ip_finish_output+0xf4/0x240 net/ipv4/ip_output.c:316
NF_HOOK_COND include/linux/netfilter.h:291 [inline]
ip_output+0xe5/0x1b0 net/ipv4/ip_output.c:430
dst_output include/net/dst.h:444 [inline]
ip_local_out+0x64/0x80 net/ipv4/ip_output.c:126
iptunnel_xmit+0x34a/0x4b0 net/ipv4/ip_tunnel_core.c:82
ip_tunnel_xmit+0x1451/0x1730 net/ipv4/ip_tunnel.c:813
__gre_xmit net/ipv4/ip_gre.c:469 [inline]
ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:661
__netdev_start_xmit include/linux/netdevice.h:4881 [inline]
netdev_start_xmit include/linux/netdevice.h:4895 [inline]
xmit_one net/core/dev.c:3580 [inline]
dev_hard_start_xmit+0x127/0x400 net/core/dev.c:3596
__dev_queue_xmit+0x1007/0x1eb0 net/core/dev.c:4246

write to 0xffff88815b9da0ec of 2 bytes by task 2379 on cpu 0:
ip_tunnel_xmit+0x1294/0x1730 net/ipv4/ip_tunnel.c:804
__gre_xmit net/ipv4/ip_gre.c:469 [inline]
ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:661
__netdev_start_xmit include/linux/netdevice.h:4881 [inline]
netdev_start_xmit include/linux/netdevice.h:4895 [inline]
xmit_one net/core/dev.c:3580 [inline]
dev_hard_start_xmit+0x127/0x400 net/core/dev.c:3596
__dev_queue_xmit+0x1007/0x1eb0 net/core/dev.c:4246
dev_queue_xmit include/linux/netdevice.h:3051 [inline]
neigh_direct_output+0x17/0x20 net/core/neighbour.c:1623
neigh_output include/net/neighbour.h:546 [inline]
ip6_finish_output2+0x9bc/0xc50 net/ipv6/ip6_output.c:134
__ip6_finish_output net/ipv6/ip6_output.c:195 [inline]
ip6_finish_output+0x39a/0x4e0 net/ipv6/ip6_output.c:206
NF_HOOK_COND include/linux/netfilter.h:291 [inline]
ip6_output+0xeb/0x220 net/ipv6/ip6_output.c:227
dst_output include/net/dst.h:444 [inline]
NF_HOOK include/linux/netfilter.h:302 [inline]
mld_sendpack+0x438/0x6a0 net/ipv6/mcast.c:1820
mld_send_cr net/ipv6/mcast.c:2121 [inline]
mld_ifc_work+0x519/0x7b0 net/ipv6/mcast.c:2653
process_one_work+0x3e6/0x750 kernel/workqueue.c:2390
worker_thread+0x5f2/0xa10 kernel/workqueue.c:2537
kthread+0x1ac/0x1e0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

value changed: 0x0dd4 -> 0x0e14

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2379 Comm: kworker/0:0 Not tainted 6.3.0-rc1-syzkaller-00002-g8ca09d5fa354-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Workqueue: mld mld_ifc_work

Fixes: 8eb30be0352d ("ipv6: Create ip6_tnl_xmit")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230310191109.2384387-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv4: tunnels: use DEV_STATS_INC()

Most of code paths in tunnels are lockless (eg NETIF_F_LLTX in tx).

Adopt SMP safe DEV_STATS_INC() to update dev->stats fields.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Respect tunnel key's "flow_flags" in IP tunnels

Commit 451ef36bd229 ("ip_tunnels: Add new flow flags field to ip_tunnel_key")
added a "flow_flags" member to struct ip_tunnel_key which was later used by
the commit in the fixes tag to avoid dropping packets with sources that
aren't locally configured when set in bpf_set_tunnel_key().

VXLAN and GENEVE were made to respect this flag, ip tunnels like IPIP and GRE
were not.

This commit fixes this omission by making ip_tunnel_init_flow() receive
the flow flags from the tunnel key in the relevant collect_md paths.

Fixes: b8fff748521c ("bpf: Set flow flag to allow any source IP in bpf_tunnel_key")
Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Paul Chaignon <paul@isovalent.com>
Link: https://lore.kernel.org/bpf/20220818074118.726639-1-eyal.birger@gmail.com

ip_tunnel: allow to inherit from VLAN encapsulated IP

The current code allows to inherit the TOS, TTL, DF from the payload
when skb->protocol is ETH_P_IP or ETH_P_IPV6.
However when the payload is VLAN encapsulated (e.g because the tunnel
is of type GRETAP), then this inheriting does not work, because the
visible skb->protocol is of type ETH_P_8021Q or ETH_P_8021AD.

Instead of skb->protocol, use skb_protocol().

Signed-off-by: Matthias May <matthias.may@westermo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ip_tunnel: use strscpy to replace strlcpy

The strlcpy should not be used because it doesn't limit the source
length. Preferred is strscpy.

Signed-off-by: XueBing Chen <chenxuebing@jari.cn>
Link: https://lore.kernel.org/r/2a08f6c1.e30.181ed8b49ad.Coremail.chenxuebing@jari.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: Handle l3mdev in ip_tunnel_init_flow

Ido reported that the commit referenced in the Fixes tag broke
a gre use case with dummy devices. Add a check to ip_tunnel_init_flow
to see if the oif is an l3mdev port and if so set the oif to 0 to
avoid the oif comparison in fib_lookup_good_nhc.

Fixes: 40867d74c374 ("net: Add l3mdev index to flow struct and avoid oif reset for port devices")
Reported-by: Ido Schimmel <idosch@idosch.org>
Signed-off-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ip: use dev_addr_set() in tunnels

Use dev_addr_set() instead of writing to netdev->dev_addr
directly in ip tunnels drivers.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ip_tunnel: use ndo_siocdevprivate

The various ipv4 and ipv6 tunnel drivers each implement a set
of 12 SIOCDEVPRIVATE commands for managing tunnels. These
all work correctly in compat mode.

Move them over to the new .ndo_siocdevprivate operation.

Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: David Ahern <dsahern@kernel.org>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Set true network header for ECN decapsulation

In cases where the header straight after the tunnel header was
another ethernet header (TEB), instead of the network header,
the ECN decapsulation code would treat the ethernet header as if
it was an IP header, resulting in mishandling and possible
wrong drops or corruption of the IP header.

In this case, ECT(1) is sent, so IP_ECN_decapsulate tries to copy it to the
inner IPv4 header, and correct its checksum.

The offset of the ECT bits in an IPv4 header corresponds to the
lower 2 bits of the second octet of the destination MAC address
in the ethernet header.
The IPv4 checksum corresponds to end of the source address.

In order to reproduce:

$ ip netns add A
$ ip netns add B
$ ip -n A link add _v0 type veth peer name _v1 netns B
$ ip -n A link set _v0 up
$ ip -n A addr add dev _v0 10.254.3.1/24
$ ip -n A route add default dev _v0 scope global
$ ip -n B link set _v1 up
$ ip -n B addr add dev _v1 10.254.1.6/24
$ ip -n B route add default dev _v1 scope global
$ ip -n B link add gre1 type gretap local 10.254.1.6 remote 10.254.3.1 key 0x49000000
$ ip -n B link set gre1 up

# Now send an IPv4/GRE/Eth/IPv4 frame where the outer header has ECT(1),
# and the inner header has no ECT bits set:

$ cat send_pkt.py
#!/usr/bin/env python3
from scapy.all import *

pkt = IP(b'E\x01\x00\xa7\x00\x00\x00\x00@/`%\n\xfe\x03\x01\n\xfe\x01\x06 \x00eXI\x00'
b'\x00\x00\x18\xbe\x92\xa0\xee&\x18\xb0\x92\xa0l&\x08\x00E\x00\x00}\x8b\x85'
b'@\x00\x01\x01\xe4\xf2\x82\x82\x82\x01\x82\x82\x82\x02\x08\x00d\x11\xa6\xeb'
b'3\x1e\x1e\\xf3\\xf7`\x00\x00\x00\x00ZN\x00\x00\x00\x00\x00\x00\x10\x11\x12'
b'\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./01234'
b'56789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ')

send(pkt)
$ sudo ip netns exec B tcpdump -neqlllvi gre1 icmp & ; sleep 1
$ sudo ip netns exec A python3 send_pkt.py

In the original packet, the source/destinatio MAC addresses are
dst=18:be:92:a0:ee:26 src=18:b0:92:a0:6c:26

In the received packet, they are
dst=18:bd:92:a0:ee:26 src=18:b0:92:a0:6c:27

Thanks to Lahav Schlesinger <lschlesinger@drivenets.com> and Isaac Garzon <isaac@speed.io>
for helping me pinpoint the origin.

Fixes: b723748750ec ("tunnel: Propagate ECT(1) when decapsulating as recommended by RFC6040")
Cc: David S. Miller <davem@davemloft.net>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: David Ahern <dsahern@kernel.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Gilad Naaman <gnaaman@drivenets.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ip_tunnel: fix mtu calculation for ETHER tunnel devices

Commit 28e104d00281 ("net: ip_tunnel: fix mtu calculation") removed
dev->hard_header_len subtraction when calculate MTU for tunnel devices
as there is an overhead for device that has header_ops.

But there are ETHER tunnel devices, like gre_tap or erspan, which don't
have header_ops but set dev->hard_header_len during setup. This makes
pkts greater than (MTU - ETH_HLEN) could not be xmited. Fix it by
subtracting the ETHER tunnel devices' dev->hard_header_len for MTU
calculation.

Fixes: 28e104d00281 ("net: ip_tunnel: fix mtu calculation")
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: always use icmp{,v6}_ndo_send from ndo_start_xmit

There were a few remaining tunnel drivers that didn't receive the prior
conversion to icmp{,v6}_ndo_send. Knowing now that this could lead to
memory corrution (see ee576c47db60 ("net: icmp: pass zeroed opts from
icmp{,v6}_ndo_send before sending") for details), there's even more
imperative to have these all converted. So this commit goes through the
remaining cases that I could find and does a boring translation to the
ndo variety.

The Fixes: line below is the merge that originally added icmp{,v6}_
ndo_send and converted the first batch of icmp{,v6}_send users. The
rationale then for the change applies equally to this patch. It's just
that these drivers were left out of the initial conversion because these
network devices are hiding in net/ rather than in drivers/net/.

Cc: Florian Westphal <fw@strlen.de>
Cc: Willem de Bruijn <willemb@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: David Ahern <dsahern@kernel.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Fixes: 803381f9f117 ("Merge branch 'icmp-account-for-NAT-when-sending-icmps-from-ndo-layer'")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ip_tunnel: fix mtu calculation

dev->hard_header_len for tunnel interface is set only when header_ops
are set too and already contains full overhead of any tunnel encapsulation.
That's why there is not need to use this overhead twice in mtu calc.

Fixes: fdafed459998 ("ip_gre: set dev->hard_header_len and dev->needed_headroom properly")
Reported-by: Slava Bacherikov <mail@slava.cc>
Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru>
Link: https://lore.kernel.org/r/1611959267-20536-1-git-send-email-vfedorenko@novek.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: fix pmtu check in nopmtudisc mode

For some reason ip_tunnel insist on setting the DF bit anyway when the
inner header has the DF bit set, EVEN if the tunnel was configured with
'nopmtudisc'.

This means that the script added in the previous commit
cannot be made to work by adding the 'nopmtudisc' flag to the
ip tunnel configuration. Doing so breaks connectivity even for the
without-conntrack/netfilter scenario.

When nopmtudisc is set, the tunnel will skip the mtu check, so no
icmp error is sent to client. Then, because inner header has DF set,
the outer header gets added with DF bit set as well.

IP stack then sends an error to itself because the packet exceeds
the device MTU.

Fixes: 23a3647bc4f93 ("ip_tunnels: Use skb-len to PMTU check.")
Cc: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ip_tunnel: fix over-mtu packet send fail without TUNNEL_DONT_FRAGMENT flags

The tunnel device such as vxlan, bareudp and geneve in the lwt mode set
the outer df only based TUNNEL_DONT_FRAGMENT.
And this was also the behavior for gre device before switching to use
ip_md_tunnel_xmit in commit 962924fa2b7a ("ip_gre: Refactor collect
metatdata mode tunnel xmit to ip_md_tunnel_xmit")

When the ip_gre in lwt mode xmit with ip_md_tunnel_xmi changed the rule and
make the discrepancy between handling of DF by different tunnels. So in the
ip_md_tunnel_xmit should follow the same rule like other tunnels.

Fixes: cfc7381b3002 ("ip_tunnel: add collect_md mode to IPIP tunnel")
Signed-off-by: wenxu <wenxu@ucloud.cn>
Link: https://lore.kernel.org/r/1604028728-31100-1-git-send-email-wenxu@ucloud.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipv4: use dev_sw_netstats_rx_add()

use new helper for netstats settings

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: fix use-after-free in ip_tunnel_lookup()

In the datapath, the ip_tunnel_lookup() is used and it internally uses
fallback tunnel device pointer, which is fb_tunnel_dev.
This pointer variable should be set to NULL when a fb interface is deleted.
But there is no routine to set fb_tunnel_dev pointer to NULL.
So, this pointer will be still used after interface is deleted and
it eventually results in the use-after-free problem.

Test commands:
ip netns add A
ip netns add B
ip link add eth0 type veth peer name eth1
ip link set eth0 netns A
ip link set eth1 netns B

ip netns exec A ip link set lo up
ip netns exec A ip link set eth0 up
ip netns exec A ip link add gre1 type gre local 10.0.0.1 \
remote 10.0.0.2
ip netns exec A ip link set gre1 up
ip netns exec A ip a a 10.0.100.1/24 dev gre1
ip netns exec A ip a a 10.0.0.1/24 dev eth0

ip netns exec B ip link set lo up
ip netns exec B ip link set eth1 up
ip netns exec B ip link add gre1 type gre local 10.0.0.2 \
remote 10.0.0.1
ip netns exec B ip link set gre1 up
ip netns exec B ip a a 10.0.100.2/24 dev gre1
ip netns exec B ip a a 10.0.0.2/24 dev eth1
ip netns exec A hping3 10.0.100.2 -2 --flood -d 60000 &
ip netns del B

Splat looks like:
[ 77.793450][ C3] ==================================================================
[ 77.794702][ C3] BUG: KASAN: use-after-free in ip_tunnel_lookup+0xcc4/0xf30
[ 77.795573][ C3] Read of size 4 at addr ffff888060bd9c84 by task hping3/2905
[ 77.796398][ C3]
[ 77.796664][ C3] CPU: 3 PID: 2905 Comm: hping3 Not tainted 5.8.0-rc1+ #616
[ 77.797474][ C3] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 77.798453][ C3] Call Trace:
[ 77.798815][ C3] <IRQ>
[ 77.799142][ C3] dump_stack+0x9d/0xdb
[ 77.799605][ C3] print_address_description.constprop.7+0x2cc/0x450
[ 77.800365][ C3] ? ip_tunnel_lookup+0xcc4/0xf30
[ 77.800908][ C3] ? ip_tunnel_lookup+0xcc4/0xf30
[ 77.801517][ C3] ? ip_tunnel_lookup+0xcc4/0xf30
[ 77.802145][ C3] kasan_report+0x154/0x190
[ 77.802821][ C3] ? ip_tunnel_lookup+0xcc4/0xf30
[ 77.803503][ C3] ip_tunnel_lookup+0xcc4/0xf30
[ 77.804165][ C3] __ipgre_rcv+0x1ab/0xaa0 [ip_gre]
[ 77.804862][ C3] ? rcu_read_lock_sched_held+0xc0/0xc0
[ 77.805621][ C3] gre_rcv+0x304/0x1910 [ip_gre]
[ 77.806293][ C3] ? lock_acquire+0x1a9/0x870
[ 77.806925][ C3] ? gre_rcv+0xfe/0x354 [gre]
[ 77.807559][ C3] ? erspan_xmit+0x2e60/0x2e60 [ip_gre]
[ 77.808305][ C3] ? rcu_read_lock_sched_held+0xc0/0xc0
[ 77.809032][ C3] ? rcu_read_lock_held+0x90/0xa0
[ 77.809713][ C3] gre_rcv+0x1b8/0x354 [gre]
[ ... ]

Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: add a new ndo_tunnel_ioctl method

This method is used to properly allow kernel callers of the IPv4 route
management ioctls. The exsting ip_tunnel_ioctl helper is renamed to
ip_tunnel_ctl to better reflect that it doesn't directly implement ioctls
touching user memory, and is used for the guts of ndo_tunnel_ctl
implementations. A new ip_tunnel_ioctl helper is added that can be wired
up directly to the ndo_do_ioctl method and takes care of the copy to and
from userspace.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net, ip_tunnel: fix interface lookup with no key

when creating a new ipip interface with no local/remote configuration,
the lookup is done with TUNNEL_NO_KEY flag, making it impossible to
match the new interface (only possible match being fallback or metada
case interface); e.g: `ip link add tunl1 type ipip dev eth0`

To fix this case, adding a flag check before the key comparison so we
permit to match an interface with no local/remote config; it also avoids
breaking possible userland tools relying on TUNNEL_NO_KEY flag and
uninitialised key.

context being on my side, I'm creating an extra ipip interface attached
to the physical one, and moving it to a dedicated namespace.

Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.")
Signed-off-by: William Dauchy <w.dauchy@criteo.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net, ip_tunnel: fix namespaces move

in the same manner as commit 690afc165bb3 ("net: ip6_gre: fix moving
ip6gre between namespaces"), fix namespace moving as it was broken since
commit 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.").
Indeed, the ip6_gre commit removed the local flag for collect_md
condition, so there is no reason to keep it for ip_gre/ip_tunnel.

this patch will fix both ip_tunnel and ip_gre modules.

Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.")
Signed-off-by: William Dauchy <w.dauchy@criteo.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tunnel: do not confirm neighbor when do pmtu update

When do tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end,
we should not call dst_confirm_neigh() as there is no two-way communication.

v5: No Change.
v4: Update commit description
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
dst_ops.update_pmtu to control whether we should do neighbor confirm.
Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.

Fixes: 0dec879f636f ("net: use dst_confirm_neigh for UDP, RAW, ICMP, L2TP")
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Tested-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 269

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of version 2 of the gnu general public license as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not write to the free
software foundation inc 51 franklin street fifth floor boston ma
02110 1301 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 21 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141334.228102212@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iptunnel: NULL pointer deref for ip_md_tunnel_xmit

Naresh Kamboju noted the following oops during execution of selftest
tools/testing/selftests/bpf/test_tunnel.sh on x86_64:

[ 274.120445] BUG: unable to handle kernel NULL pointer dereference
at 0000000000000000
[ 274.128285] #PF error: [INSTR]
[ 274.131351] PGD 8000000414a0e067 P4D 8000000414a0e067 PUD 3b6334067 PMD 0
[ 274.138241] Oops: 0010 [#1] SMP PTI
[ 274.141734] CPU: 1 PID: 11464 Comm: ping Not tainted
5.0.0-rc4-next-20190129 #1
[ 274.149046] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
2.0b 07/27/2017
[ 274.156526] RIP: 0010: (null)
[ 274.160280] Code: Bad RIP value.
[ 274.163509] RSP: 0018:ffffbc9681f83540 EFLAGS: 00010286
[ 274.168726] RAX: 0000000000000000 RBX: ffffdc967fa80a18 RCX: 0000000000000000
[ 274.175851] RDX: ffff9db2ee08b540 RSI: 000000000000000e RDI: ffffdc967fa809a0
[ 274.182974] RBP: ffffbc9681f83580 R08: ffff9db2c4d62690 R09: 000000000000000c
[ 274.190098] R10: 0000000000000000 R11: ffff9db2ee08b540 R12: ffff9db31ce7c000
[ 274.197222] R13: 0000000000000001 R14: 000000000000000c R15: ffff9db3179cf400
[ 274.204346] FS: 00007ff4ae7c5740(0000) GS:ffff9db31fa80000(0000)
knlGS:0000000000000000
[ 274.212424] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 274.218162] CR2: ffffffffffffffd6 CR3: 00000004574da004 CR4: 00000000003606e0
[ 274.225292] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 274.232416] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 274.239541] Call Trace:
[ 274.241988] ? tnl_update_pmtu+0x296/0x3b0
[ 274.246085] ip_md_tunnel_xmit+0x1bc/0x520
[ 274.250176] gre_fb_xmit+0x330/0x390
[ 274.253754] gre_tap_xmit+0x128/0x180
[ 274.257414] dev_hard_start_xmit+0xb7/0x300
[ 274.261598] sch_direct_xmit+0xf6/0x290
[ 274.265430] __qdisc_run+0x15d/0x5e0
[ 274.269007] __dev_queue_xmit+0x2c5/0xc00
[ 274.273011] ? dev_queue_xmit+0x10/0x20
[ 274.276842] ? eth_header+0x2b/0xc0
[ 274.280326] dev_queue_xmit+0x10/0x20
[ 274.283984] ? dev_queue_xmit+0x10/0x20
[ 274.287813] arp_xmit+0x1a/0xf0
[ 274.290952] arp_send_dst.part.19+0x46/0x60
[ 274.295138] arp_solicit+0x177/0x6b0
[ 274.298708] ? mod_timer+0x18e/0x440
[ 274.302281] neigh_probe+0x57/0x70
[ 274.305684] __neigh_event_send+0x197/0x2d0
[ 274.309862] neigh_resolve_output+0x18c/0x210
[ 274.314212] ip_finish_output2+0x257/0x690
[ 274.318304] ip_finish_output+0x219/0x340
[ 274.322314] ? ip_finish_output+0x219/0x340
[ 274.326493] ip_output+0x76/0x240
[ 274.329805] ? ip_fragment.constprop.53+0x80/0x80
[ 274.334510] ip_local_out+0x3f/0x70
[ 274.337992] ip_send_skb+0x19/0x40
[ 274.341391] ip_push_pending_frames+0x33/0x40
[ 274.345740] raw_sendmsg+0xc15/0x11d0
[ 274.349403] ? __might_fault+0x85/0x90
[ 274.353151] ? _copy_from_user+0x6b/0xa0
[ 274.357070] ? rw_copy_check_uvector+0x54/0x130
[ 274.361604] inet_sendmsg+0x42/0x1c0
[ 274.365179] ? inet_sendmsg+0x42/0x1c0
[ 274.368937] sock_sendmsg+0x3e/0x50
[ 274.372460] ___sys_sendmsg+0x26f/0x2d0
[ 274.376293] ? lock_acquire+0x95/0x190
[ 274.380043] ? __handle_mm_fault+0x7ce/0xb70
[ 274.384307] ? lock_acquire+0x95/0x190
[ 274.388053] ? __audit_syscall_entry+0xdd/0x130
[ 274.392586] ? ktime_get_coarse_real_ts64+0x64/0xc0
[ 274.397461] ? __audit_syscall_entry+0xdd/0x130
[ 274.401989] ? trace_hardirqs_on+0x4c/0x100
[ 274.406173] __sys_sendmsg+0x63/0xa0
[ 274.409744] ? __sys_sendmsg+0x63/0xa0
[ 274.413488] __x64_sys_sendmsg+0x1f/0x30
[ 274.417405] do_syscall_64+0x55/0x190
[ 274.421064] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 274.426113] RIP: 0033:0x7ff4ae0e6e87
[ 274.429686] Code: 64 89 02 48 c7 c0 ff ff ff ff eb b9 0f 1f 80 00
00 00 00 8b 05 ca d9 2b 00 48 63 d2 48 63 ff 85 c0 75 10 b8 2e 00 00
00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 53 48 89 f3 48 83 ec 10 48 89 7c
24 08
[ 274.448422] RSP: 002b:00007ffcd9b76db8 EFLAGS: 00000246 ORIG_RAX:
000000000000002e
[ 274.455978] RAX: ffffffffffffffda RBX: 0000000000000040 RCX: 00007ff4ae0e6e87
[ 274.463104] RDX: 0000000000000000 RSI: 00000000006092e0 RDI: 0000000000000003
[ 274.470228] RBP: 0000000000000000 R08: 00007ffcd9bc40a0 R09: 00007ffcd9bc4080
[ 274.477349] R10: 000000000000060a R11: 0000000000000246 R12: 0000000000000003
[ 274.484475] R13: 0000000000000016 R14: 00007ffcd9b77fa0 R15: 00007ffcd9b78da4
[ 274.491602] Modules linked in: cls_bpf sch_ingress iptable_filter
ip_tables algif_hash af_alg x86_pkg_temp_thermal fuse [last unloaded:
test_bpf]
[ 274.504634] CR2: 0000000000000000
[ 274.507976] ---[ end trace 196d18386545eae1 ]---
[ 274.512588] RIP: 0010: (null)
[ 274.516334] Code: Bad RIP value.
[ 274.519557] RSP: 0018:ffffbc9681f83540 EFLAGS: 00010286
[ 274.524775] RAX: 0000000000000000 RBX: ffffdc967fa80a18 RCX: 0000000000000000
[ 274.531921] RDX: ffff9db2ee08b540 RSI: 000000000000000e RDI: ffffdc967fa809a0
[ 274.539082] RBP: ffffbc9681f83580 R08: ffff9db2c4d62690 R09: 000000000000000c
[ 274.546205] R10: 0000000000000000 R11: ffff9db2ee08b540 R12: ffff9db31ce7c000
[ 274.553329] R13: 0000000000000001 R14: 000000000000000c R15: ffff9db3179cf400
[ 274.560456] FS: 00007ff4ae7c5740(0000) GS:ffff9db31fa80000(0000)
knlGS:0000000000000000
[ 274.568541] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 274.574277] CR2: ffffffffffffffd6 CR3: 00000004574da004 CR4: 00000000003606e0
[ 274.581403] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 274.588535] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 274.595658] Kernel panic - not syncing: Fatal exception in interrupt
[ 274.602046] Kernel Offset: 0x14400000 from 0xffffffff81000000
(relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[ 274.612827] ---[ end Kernel panic - not syncing: Fatal exception in
interrupt ]---
[ 274.620387] ------------[ cut here ]------------

I'm also seeing the same failure on x86_64, and it reproduces
consistently.

>From poking around it looks like the skb's dst entry is being used
to calculate the mtu in:

mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;

...but because that dst_entry has an "ops" value set to md_dst_ops,
the various ops (including mtu) are not set:

crash> struct sk_buff._skb_refdst ffff928f87447700 -x
_skb_refdst = 0xffffcd6fbf5ea590
crash> struct dst_entry.ops 0xffffcd6fbf5ea590
ops = 0xffffffffa0193800
crash> struct dst_ops.mtu 0xffffffffa0193800
mtu = 0x0
crash>

I confirmed that the dst entry also has dst->input set to
dst_md_discard, so it looks like it's an entry that's been
initialized via __metadata_dst_init alright.

I think the fix here is to use skb_valid_dst(skb) - it checks
for DST_METADATA also, and with that fix in place, the
problem - which was previously 100% reproducible - disappears.

The below patch resolves the panic and all bpf tunnel tests pass
without incident.

Fixes: c8b34e680a09 ("ip_tunnel: Add tnl_update_pmtu in ip_md_tunnel_xmit")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Tested-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

route: Add multipath_hash in flowi_common to make user-define hash

Current fib_multipath_hash_policy can make hash based on the L3 or
L4. But it only work on the outer IP. So a specific tunnel always
has the same hash value. But a specific tunnel may contain so many
inner connections.

This patch provide a generic multipath_hash in floi_common. It can
make a user-define hash which can mix with L3 or L4 hash.

Signed-off-by: wenxu <wenxu@ucloud.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Add ip tunnel tun_info type dst_cache in ip_tunnel_xmit

ip l add dev tun type gretap key 1000

Non-tunnel-dst ip tunnel device can send packet through lwtunnel
This patch provide the tun_inf dst cache support for this mode.

Signed-off-by: wenxu <wenxu@ucloud.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Fix route fl4 init in ip_md_tunnel_xmit

Init the gre_key from tuninfo->key.tun_id and init the mark
from the skb->mark, set the oif to zero in the collect metadata
mode.

Fixes: cfc7381b3002 ("ip_tunnel: add collect_md mode to IPIP tunnel")
Signed-off-by: wenxu <wenxu@ucloud.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Add tnl_update_pmtu in ip_md_tunnel_xmit

Add tnl_update_pmtu in ip_md_tunnel_xmit to dynamic modify
the pmtu which packet send through collect_metadata mode
ip tunnel

Signed-off-by: wenxu <wenxu@ucloud.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Add ip tunnel dst_cache in ip_md_tunnel_xmit

Add ip tunnel dst cache in ip_md_tunnel_xmit to make more
efficient for the route lookup.

Signed-off-by: wenxu <wenxu@ucloud.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Make none-tunnel-dst tunnel port work with lwtunnel

ip l add dev tun type gretap key 1000
ip a a dev tun 10.0.0.1/24

Packets with tun-id 1000 can be recived by tun dev. But packet can't
be sent through dev tun for non-tunnel-dst

With this patch: tunnel-dst can be get through lwtunnel like beflow:
ip r a 10.0.0.7 encap ip dst 172.168.0.11 dev tun

Signed-off-by: wenxu <wenxu@ucloud.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip: validate header length on virtual device xmit

KMSAN detected read beyond end of buffer in vti and sit devices when
passing truncated packets with PF_PACKET. The issue affects additional
ip tunnel devices.

Extend commit 76c0ddd8c3a6 ("ip6_tunnel: be careful when accessing the
inner header") and commit ccfec9e5cb2d ("ip_tunnel: be careful when
accessing the inner header").

Move the check to a separate helper and call at the start of each
ndo_start_xmit function in net/ipv4 and net/ipv6.

Minor changes:
- convert dev_kfree_skb to kfree_skb on error path,
as dev_kfree_skb calls consume_skb which is not for error paths.
- use pskb_network_may_pull even though that is pedantic here,
as the same as pskb_may_pull for devices without llheaders.
- do not cache ipv6 hdrs if used only once
(unsafe across pskb_may_pull, was more relevant to earlier patch)

Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: be careful when accessing the inner header

Cong noted that we need the same checks introduced by commit 76c0ddd8c3a6
("ip6_tunnel: be careful when accessing the inner header")
even for ipv4 tunnels.

Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.")
Suggested-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Fix name string concatenate in __ip_tunnel_create()

By passing a limit of 2 bytes to strncat, strncat is limited to writing
fewer bytes than what it's supposed to append to the name here.

Since the bounds are checked on the line above this, just remove the string
bounds checks entirely since they're unneeded.

Signed-off-by: Sultan Alsawaf <sultanxda@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: restore binding to ifaces with a large mtu

After commit f6cc9c054e77, the following conf is broken (note that the
default loopback mtu is 65536, ie IP_MAX_MTU + 1):

$ ip tunnel add gre1 mode gre local 10.125.0.1 remote 10.125.0.2 dev lo
add tunnel "gre0" failed: Invalid argument
$ ip l a type dummy
$ ip l s dummy1 up
$ ip l s dummy1 mtu 65535
$ ip tunnel add gre1 mode gre local 10.125.0.1 remote 10.125.0.2 dev dummy1
add tunnel "gre0" failed: Invalid argument

dev_set_mtu() doesn't allow to set a mtu which is too large.
First, let's cap the mtu returned by ip_tunnel_bind_dev(). Second, remove
the magic value 0xFFF8 and use IP_MAX_MTU instead.
0xFFF8 seems to be there for ages, I don't know why this value was used.

With a recent kernel, it's also possible to set a mtu > IP_MAX_MTU:
$ ip l s dummy1 mtu 66000
After that patch, it's also possible to bind an ip tunnel on that kind of
interface.

CC: Petr Machata <petrm@mellanox.com>
CC: Ido Schimmel <idosch@mellanox.com>
Link: https://git.kernel.org/pub/scm/linux/kernel/git/davem/netdev-vger-cvs.git/commit/?id=e5afd356a411a
Fixes: f6cc9c054e77 ("ip_tunnel: Emit events for post-register MTU changes")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: better validate user provided tunnel names

Use dev_valid_name() to make sure user does not provide illegal
device name.

syzbot caught the following bug :

BUG: KASAN: stack-out-of-bounds in strlcpy include/linux/string.h:300 [inline]
BUG: KASAN: stack-out-of-bounds in __ip_tunnel_create+0xca/0x6b0 net/ipv4/ip_tunnel.c:257
Write of size 20 at addr ffff8801ac79f810 by task syzkaller268107/4482

CPU: 0 PID: 4482 Comm: syzkaller268107 Not tainted 4.16.0+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b9/0x29f lib/dump_stack.c:53
print_address_description+0x6c/0x20b mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.7+0xac/0x2f5 mm/kasan/report.c:412
check_memory_region_inline mm/kasan/kasan.c:260 [inline]
check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
memcpy+0x37/0x50 mm/kasan/kasan.c:303
strlcpy include/linux/string.h:300 [inline]
__ip_tunnel_create+0xca/0x6b0 net/ipv4/ip_tunnel.c:257
ip_tunnel_create net/ipv4/ip_tunnel.c:352 [inline]
ip_tunnel_ioctl+0x818/0xd40 net/ipv4/ip_tunnel.c:861
ipip_tunnel_ioctl+0x1c5/0x420 net/ipv4/ipip.c:350
dev_ifsioc+0x43e/0xb90 net/core/dev_ioctl.c:334
dev_ioctl+0x69a/0xcc0 net/core/dev_ioctl.c:525
sock_ioctl+0x47e/0x680 net/socket.c:1015
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x1cf/0x1650 fs/ioctl.c:684
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
SYSC_ioctl fs/ioctl.c:708 [inline]
SyS_ioctl+0x24/0x30 fs/ioctl.c:706
do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x42/0xb7

Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Resolve ipsec merge conflict properly.

We want to use dev_set_mtu() regardless of how we calculate
the mtu value.

Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Emit events for post-register MTU changes

For tunnels created with IFLA_MTU, MTU of the netdevice is set by
rtnl_create_link() (called from rtnl_newlink()) before the device is
registered. However without IFLA_MTU that's not done.

rtnl_newlink() proceeds by calling struct rtnl_link_ops.newlink, which
via ip_tunnel_newlink() calls register_netdevice(), and that emits
NETDEV_REGISTER. Thus any listeners that inspect the netdevice get the
MTU of 0.

After ip_tunnel_newlink() corrects the MTU after registering the
netdevice, but since there's no event, the listeners don't get to know
about the MTU until something else happens--such as a NETDEV_UP event.
That's not ideal.

So instead of setting the MTU directly, go through dev_set_mtu(), which
takes care of distributing the necessary NETDEV_PRECHANGEMTU and
NETDEV_CHANGEMTU events.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Clamp MTU to bounds on new link

Otherwise, it's possible to specify invalid MTU values directly
on creation of a link (via 'ip link add'). This is already
prevented on subsequent MTU changes by commit b96f9afee4eb
("ipv4/6: use core net MTU range checking").

Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Acked-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net: do not create fallback tunnels for non-default namespaces

fallback tunnels (like tunl0, gre0, gretap0, erspan0, sit0,
ip6tnl0, ip6gre0) are automatically created when the corresponding
module is loaded.

These tunnels are also automatically created when a new network
namespace is created, at a great cost.

In many cases, netns are used for isolation purposes, and these
extra network devices are a waste of resources. We are using
thousands of netns per host, and hit the netns creation/delete
bottleneck a lot. (Many thanks to Kirill for recent work on this)

Add a new sysctl so that we can opt-out from this automatic creation.

Note that these tunnels are still created for the initial namespace,
to be the least intrusive for typical setups.

Tested:
lpk43:~# cat add_del_unshare.sh
for i in `seq 1 40`
do
(for j in `seq 1 100` ; do unshare -n /bin/true >/dev/null ; done) &
done
wait

lpk43:~# echo 0 >/proc/sys/net/core/fb_tunnels_only_for_init_net
lpk43:~# time ./add_del_unshare.sh

real 0m37.521s
user 0m0.886s
sys 7m7.084s
lpk43:~# echo 1 >/proc/sys/net/core/fb_tunnels_only_for_init_net
lpk43:~# time ./add_del_unshare.sh

real 0m4.761s
user 0m0.851s
sys 1m8.343s
lpk43:~#

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Rename & publish init_tunnel_flow

Initializing struct flowi4 is useful for drivers that need to emulate
routing decisions made by a tunnel interface. Publish the
function (appropriately renamed) so that the drivers in question don't
need to cut'n'paste it around.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Do not use mark in skb by default

This reverts commit 5c38bd1b82e1f76f9fa96c1e61c9897cabf1ce45.

skb->mark contains the mark the encapsulated traffic which
can result in incorrect routing decisions being made such
as routing loops if the route chosen is via tunnel itself.
The correct method should be to use tunnel->fwmark.

Signed-off-by: Thomas Winter <thomas.winter@alliedtelesis.co.nz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: don't call update_pmtu unconditionally

Some dst_ops (e.g. md_dst_ops)) doesn't set this handler. It may result to:
"BUG: unable to handle kernel NULL pointer dereference at (null)"

Let's add a helper to check if update_pmtu is available before calling it.

Fixes: 52a589d51f10 ("geneve: update skb dst pmtu on tx path")
Fixes: a93bf0ff4490 ("vxlan: update skb dst pmtu on tx path")
CC: Roman Kapl <code@rkapl.cz>
CC: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Use mark in skb by default

This allows marks set by connmark in iptables
to be used for route lookups.

Signed-off-by: Thomas Winter <thomas.winter@alliedtelesis.co.nz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: igmp: guard against silly MTU values

IPv4 stack reacts to changes to small MTU, by disabling itself under
RTNL.

But there is a window where threads not using RTNL can see a wrong
device mtu. This can lead to surprises, in igmp code where it is
assumed the mtu is suitable.

Fix this by reading device mtu once and checking IPv4 minimal MTU.

This patch adds missing IPV4_MIN_MTU define, to not abuse
ETH_MIN_MTU anymore.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: speedup ipv6 tunnels dismantle

Implement exit_batch() method to dismantle more devices
per round.

(rtnl_lock() ...
unregister_netdevice_many() ...
rtnl_unlock())

Tested:
$ cat add_del_unshare.sh
for i in `seq 1 40`
do
(for j in `seq 1 100` ; do unshare -n /bin/true >/dev/null ; done) &
done
wait ; grep net_namespace /proc/slabinfo

Before patch :
$ time ./add_del_unshare.sh
net_namespace 126 282 5504 1 2 : tunables 8 4 0 : slabdata 126 282 0

real 1m38.965s
user 0m0.688s
sys 0m37.017s

After patch:
$ time ./add_del_unshare.sh
net_namespace 135 291 5504 1 2 : tunables 8 4 0 : slabdata 135 291 0

real 0m22.117s
user 0m0.728s
sys 0m35.328s

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: fix ip tunnel lookup in collect_md mode

In collect_md mode, if the tun dev is down, it still can call
ip_tunnel_rcv to receive on packets, and the rx statistics increase
improperly.

When the md tunnel is down, it's not neccessary to increase RX drops
for the tunnel device, packets would be recieved on fallback tunnel,
and the RX drops on fallback device will be increased as expected.

Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.")
Cc: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: fix setting ttl and tos value in collect_md mode

ttl and tos variables are declared and assigned, but are not used in
iptunnel_xmit() function.

Fixes: cfc7381b3002 ("ip_tunnel: add collect_md mode to IPIP tunnel")
Cc: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: fix potential issue in ip_tunnel_rcv

When ip_tunnel_rcv fails, the tun_dst won't be freed, so call
dst_release to free it in error code path.

Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.")
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Tested-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Fix inconsistent teardown and release of private netdev state.

Network devices can allocate reasources and private memory using
netdev_ops->ndo_init(). However, the release of these resources
can occur in one of two different places.

Either netdev_ops->ndo_uninit() or netdev->destructor().

The decision of which operation frees the resources depends upon
whether it is necessary for all netdev refs to be released before it
is safe to perform the freeing.

netdev_ops->ndo_uninit() presumably can occur right after the
NETDEV_UNREGISTER notifier completes and the unicast and multicast
address lists are flushed.

netdev->destructor(), on the other hand, does not run until the
netdev references all go away.

Further complicating the situation is that netdev->destructor()
almost universally does also a free_netdev().

This creates a problem for the logic in register_netdevice().
Because all callers of register_netdevice() manage the freeing
of the netdev, and invoke free_netdev(dev) if register_netdevice()
fails.

If netdev_ops->ndo_init() succeeds, but something else fails inside
of register_netdevice(), it does call ndo_ops->ndo_uninit(). But
it is not able to invoke netdev->destructor().

This is because netdev->destructor() will do a free_netdev() and
then the caller of register_netdevice() will do the same.

However, this means that the resources that would normally be released
by netdev->destructor() will not be.

Over the years drivers have added local hacks to deal with this, by
invoking their destructor parts by hand when register_netdevice()
fails.

Many drivers do not try to deal with this, and instead we have leaks.

Let's close this hole by formalizing the distinction between what
private things need to be freed up by netdev->destructor() and whether
the driver needs unregister_netdevice() to perform the free_netdev().

netdev->priv_destructor() performs all actions to free up the private
resources that used to be freed by netdev->destructor(), except for
free_netdev().

netdev->needs_free_netdev is a boolean that indicates whether
free_netdev() should be done at the end of unregister_netdevice().

Now, register_netdevice() can sanely release all resources after
ndo_ops->ndo_init() succeeds, by invoking both ndo_ops->ndo_uninit()
and netdev->priv_destructor().

And at the end of unregister_netdevice(), we invoke
netdev->priv_destructor() and optionally call free_netdev().

Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Allow policy-based routing through tunnels

This feature allows the administrator to set an fwmark for
packets traversing a tunnel. This allows the use of independent
routing tables for tunneled packets without the use of iptables.

There is no concept of per-packet routing decisions through IPv4
tunnels, so this implementation does not need to work with
per-packet route lookups as the v6 implementation may
(with IP6_TNL_F_USE_ORIG_FWMARK).

Further, since the v4 tunnel ioctls share datastructures
(which can not be trivially modified) with the kernel's internal
tunnel configuration structures, the mark attribute must be stored
in the tunnel structure itself and passed as a parameter when
creating or changing tunnel attributes.

Signed-off-by: Craig Gallek <kraig@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netns: make struct pernet_operations::id unsigned int

Make struct pernet_operations::id unsigned.

There are 2 reasons to do so:

1)
This field is really an index into an zero based array and
thus is unsigned entity. Using negative value is out-of-bound
access by definition.

2)
On x86_64 unsigned 32-bit data which are mixed with pointers
via array indexing or offsets added or subtracted to pointers
are preffered to signed 32-bit data.

"int" being used as an array index needs to be sign-extended
to 64-bit before being used.

void f(long *p, int i)
{
g(p[i]);
}

roughly translates to

movsx rsi, esi
mov rdi, [rsi+...]
call g

MOVSX is 3 byte instruction which isn't necessary if the variable is
unsigned because x86_64 is zero extending by default.

Now, there is net_generic() function which, you guessed it right, uses
"int" as an array index:

static inline void *net_generic(const struct net *net, int id)
{
...
ptr = ng->ptr[id - 1];
...
}

And this function is used a lot, so those sign extensions add up.

Patch snipes ~1730 bytes on allyesconfig kernel (without all junk
messing with code generation):

add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)

Unfortunately some functions actually grow bigger.
This is a semmingly random artefact of code generation with register
allocator being used differently. gcc decides that some variable
needs to live in new r8+ registers and every access now requires REX
prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be
used which is longer than [r8]

However, overall balance is in negative direction:

add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
function old new delta
nfsd4_lock 3886 3959 +73
tipc_link_build_proto_msg 1096 1140 +44
mac80211_hwsim_new_radio 2776 2808 +32
tipc_mon_rcv 1032 1058 +26
svcauth_gss_legacy_init 1413 1429 +16
tipc_bcbase_select_primary 379 392 +13
nfsd4_exchange_id 1247 1260 +13
nfsd4_setclientid_confirm 782 793 +11
...
put_client_renew_locked 494 480 -14
ip_set_sockfn_get 730 716 -14
geneve_sock_add 829 813 -16
nfsd4_sequence_done 721 703 -18
nlmclnt_lookup_host 708 686 -22
nfsd4_lockt 1085 1063 -22
nfs_get_client 1077 1050 -27
tcf_bpf_init 1106 1076 -30
nfsd4_encode_fattr 5997 5930 -67
Total: Before=154856051, After=154854321, chg -0.00%

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4/6: use core net MTU range checking

ipv4/ip_tunnel:
- min_mtu = 68, max_mtu = 0xFFF8 - dev->hard_header_len - t_hlen
- preserve all ndo_change_mtu checks for now to prevent regressions

ipv6/ip6_tunnel:
- min_mtu = 68, max_mtu = 0xFFF8 - dev->hard_header_len
- preserve all ndo_change_mtu checks for now to prevent regressions

ipv6/ip6_vti:
- min_mtu = 1280, max_mtu = 65535
- remove redundant vti6_change_mtu

ipv6/sit:
- min_mtu = 1280, max_mtu = 0xFFF8 - t_hlen
- remove redundant ipip6_tunnel_change_mtu

CC: netdev@vger.kernel.org
CC: "David S. Miller" <davem@davemloft.net>
CC: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
CC: James Morris <jmorris@namei.org>
CC: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
CC: Patrick McHardy <kaber@trash.net>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: add collect_md mode to IPIP tunnel

Similar to gre, vxlan, geneve tunnels allow IPIP tunnels to
operate in 'collect metadata' mode.
bpf_skb_[gs]et_tunnel_key() helpers can make use of it right away.
ovs can use it as well in the future (once appropriate ovs-vport
abstractions and user apis are added).
Note that just like in other tunnels we cannot cache the dst,
since tunnel_info metadata can be different for every packet.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv4: Add ability to have GRE ignore DF bit in IPv4 payloads

In the presence of firewalls which improperly block ICMP Unreachable
(including Fragmentation Required) messages, Path MTU Discovery is
prevented from working.

A workaround is to handle IPv4 payloads opaquely, ignoring the DF bit--as
is done for other payloads like AppleTalk--and doing transparent
fragmentation and reassembly.

Redux includes the enforcement of mutual exclusion between this feature
and Path MTU Discovery as suggested by Alexander Duyck.

Cc: Alexander Duyck <alexander.duyck@gmail.com>
Reviewed-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Philip Prindeville <philipp@redfish-solutions.com>

Signed-off-by: David S. Miller <davem@davemloft.net>

net: Cleanup encap items in ip_tunnels.h

Consolidate all the ip_tunnel_encap definitions in one spot in the
header file. Also, move ip_encap_hlen and ip_tunnel_encap from
ip_tunnel.c to ip_tunnels.h so they call be called without a dependency
on ip_tunnel module. Similarly, move iptun_encaps to ip_tunnel_core.c.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: fix preempt warning in ip tunnel creation/updating

After the commit e09acddf873b ("ip_tunnel: replace dst_cache with generic
implementation"), a preemption debug warning is triggered on ip4
tunnels updating; the dst cache helper needs to be invoked in unpreemptible
context.

We don't need to load the cache on tunnel update, so this commit fixes
the warning replacing the load with a dst cache reset, which is
preempt safe.

Fixes: e09acddf873b ("ip_tunnel: replace dst_cache with generic implementation")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tunnel: Clear IPCB(skb)->opt before dst_link_failure called

IPCB may contain data from previous layers (in the observed case the
qdisc layer). In the observed scenario, the data was misinterpreted as
ip header options, which later caused the ihl to be set to an invalid
value (<5). This resulted in an infinite loop in the mips implementation
of ip_fast_csum.

This patch clears IPCB(skb)->opt before dst_link_failure can be called for
various types of tunnels. This change only applies to encapsulated ipv4
packets.

The code introduced in 11c21a30 which clears all of IPCB has been removed
to be consistent with these changes, and instead the opt field is cleared
unconditionally in ip_tunnel_xmit. The change in ip_tunnel_xmit applies to
SIT, GRE, and IPIP tunnels.

The relevant vti, l2tp, and pptp functions already contain similar code for
clearing the IPCB.

Signed-off-by: Bernie Harris <bernie.harris@alliedtelesis.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: replace dst_cache with generic implementation

The current ip_tunnel cache implementation is prone to a race
that will cause the wrong dst to be cached on cuncurrent dst cache
miss and ip tunnel update via netlink.

Replacing with the generic implementation fix the issue.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Suggested-and-acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

vxlan, gre, geneve: Set a large MTU on ovs-created tunnel devices

Prior to 4.3, openvswitch tunnel vports (vxlan, gre and geneve) could
transmit vxlan packets of any size, constrained only by the ability to
send out the resulting packets. 4.3 introduced netdevs corresponding
to tunnel vports. These netdevs have an MTU, which limits the size of
a packet that can be successfully encapsulated. The default MTU
values are low (1500 or less), which is awkwardly small in the context
of physical networks supporting jumbo frames, and leads to a
conspicuous change in behaviour for userspace.

Instead, set the MTU on openvswitch-created netdevs to be the relevant
maximum (i.e. the maximum IP packet size minus any relevant overhead),
effectively restoring the behaviour prior to 4.3.

Signed-off-by: David Wragg <david@weave.works>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Move stats update to iptunnel_xmit()

By moving stats update into iptunnel_xmit(), we can simplify
iptunnel_xmit() usage. With this change there is no need to
call another function (iptunnel_xmit_stats()) to update stats
in tunnel xmit code path.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: remove unnecessary mroute.h includes

It looks like many files are including mroute.h unnecessarily, so remove
the include. Most importantly remove it from ipv6.

CC: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
CC: Steffen Klassert <steffen.klassert@secunet.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_gre: Add support to collect tunnel metadata.

Following patch create new tunnel flag which enable
tunnel metadata collection on given device.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: fix ipv4 pmtu check to honor inner ip header df

Frag needed should be sent only if the inner header asked
to not fragment. Currently fragmentation is broken if the
tunnel has df set, but df was not asked in the original
packet. The tunnel's df needs to be still checked to update
internally the pmtu cache.

Commit 23a3647bc4f93bac broke it, and this commit fixes
the ipv4 df check back to the way it was.

Fixes: 23a3647bc4f93bac ("ip_tunnels: Use skb-len to PMTU check.")
Cc: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

udp_tunnel: Pass UDP socket down through udp_tunnel{, 6}_xmit_skb().

That was we can make sure the output path of ipv4/ipv6 operate on
the UDP socket rather than whatever random thing happens to be in
skb->sk.

Based upon a patch by Jiri Pirko.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>

ipv4: coding style: comparison for inequality with NULL

The ipv4 code uses a mixture of coding styles. In some instances check
for non-NULL pointer is done as x != NULL and sometimes as x. x is
preferred according to checkpatch and this patch makes the code
consistent by adopting the latter form.

No changes detected by objdiff.

Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: coding style: comparison for equality with NULL

The ipv4 code uses a mixture of coding styles. In some instances check
for NULL pointer is done as x == NULL and sometimes as !x. !x is
preferred according to checkpatch and this patch makes the code
consistent by adopting the latter form.

No changes detected by objdiff.

Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipip,gre,vti,sit: implement ndo_get_iflink

Don't use dev->iflink anymore.

CC: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tunnels: advertise link netns via netlink

Implement rtnl_link_ops->get_link_net() callback so that IFLA_LINK_NETNSID is
added to rtnetlink messages.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Add missing validation of encap type to ip_tunnel_encap_setup()

The encap->type comes straight from Netlink. Validate it against
max supported encap types just like ip_encap_hlen() already does.

Fixes: a8c5f9 ("ip_tunnel: Ops registration for secondary encap (fou, gue)")
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Add sanity checks to ip_tunnel_encap_add_ops()

The symbols are exported and could be used by external modules.

Fixes: a8c5f9 ("ip_tunnel: Ops registration for secondary encap (fou, gue)")
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Ops registration for secondary encap (fou, gue)

Instead of calling fou and gue functions directly from ip_tunnel
use ops for these that were previously registered. This patch adds the
logic to add and remove encapsulation operations for ip_tunnel,
and modified fou (and gue) to register with ip_tunnels.

This patch also addresses a circular dependency between ip_tunnel
and fou that was causing link errors when CONFIG_NET_IP_TUNNEL=y
and CONFIG_NET_FOU=m. References to fou an gue have been removed from
ip_tunnel.c

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Move fou_build_header into fou.c and refactor

Move fou_build_header out of ip_tunnel.c and into fou.c splitting
it up into fou_build_header, gue_build_header, and fou_build_udp.
This allows for other users for TX of FOU or GUE. Change ip_tunnel_encap
to call fou_build_header or gue_build_header based on the tunnel
encapsulation type. Similarly, added fou_encap_hlen and gue_encap_hlen
functions which are called by ip_encap_hlen. New net/fou.h has
prototypes and defines for this.

Added NET_FOU_IP_TUNNELS configuration. When this is set, IP tunnels
can use FOU/GUE and fou module is also selected.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Add GUE support

This patch allows configuring IPIP, sit, and GRE tunnels to use GUE.
This is very similar to fou excpet that we need to insert the GUE header
in addition to the UDP header on transmit.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Account for secondary encapsulation header in max_headroom

When adjusting max_header for the tunnel interface based on egress
device we need to account for any extra bytes in secondary encapsulation
(e.g. FOU).

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Don't allow to add the same tunnel multiple times.

When we try to add an already existing tunnel, we don't return
an error. Instead we continue and call ip_tunnel_update().
This means that we can change existing tunnels by adding
the same tunnel multiple times. It is even possible to change
the tunnel endpoints of the fallback device.

We fix this by returning an error if we try to add an existing
tunnel.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: do not use this_cpu_ptr() in preemptible context

this_cpu_ptr() in preemptible context is generally bad

Sep 22 05:05:55 br kernel: [ 94.608310] BUG: using smp_processor_id()
in
preemptible [00000000] code: ip/2261
Sep 22 05:05:55 br kernel: [ 94.608316] caller is
tunnel_dst_set.isra.28+0x20/0x60 [ip_tunnel]
Sep 22 05:05:55 br kernel: [ 94.608319] CPU: 3 PID: 2261 Comm: ip Not
tainted
3.17.0-rc5 #82

We can simply use raw_cpu_ptr(), as preemption is safe in these
contexts.

Should fix https://bugzilla.kernel.org/show_bug.cgi?id=84991

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Joe <joe9mail@gmail.com>
Fixes: 9a4aa9af447f ("ipv4: Use percpu Cache route in IP tunnels")
Acked-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Changes to ip_tunnel to support foo-over-udp encapsulation

This patch changes IP tunnel to support (secondary) encapsulation,
Foo-over-UDP. Changes include:

1) Adding tun_hlen as the tunnel header length, encap_hlen as the
encapsulation header length, and hlen becomes the grand total
of these.
2) Added common netlink define to support FOU encapsulation.
3) Routines to perform FOU encapsulation.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel(ipv4): fix tunnels with "local any remote $remote_ip"

Ipv4 tunnels created with "local any remote $ip" didn't work properly since
7d442fab0 (ipv4: Cache dst in tunnels). 99% of packets sent via those tunnels
had src addr = 0.0.0.0. That was because only dst_entry was cached, although
fl4.saddr has to be cached too. Every time ip_tunnel_xmit used cached dst_entry
(tunnel_rtable_get returned non-NULL), fl4.saddr was initialized with
tnl_params->saddr (= 0 in our case), and wasn't changed until iptunnel_xmit().

This patch adds saddr to ip_tunnel->dst_cache, fixing this issue.

Reported-by: Sergey Popov <pinkbyte@gentoo.org>
Signed-off-by: Dmitry Popov <ixaphire@qrator.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: set name_assign_type in alloc_netdev()

Extend alloc_netdev{,_mq{,s}}() to take name_assign_type as argument, and convert
all users to pass NET_NAME_UNKNOWN.

Coccinelle patch:

@@
expression sizeof_priv, name, setup, txqs, rxqs, count;
@@

(
-alloc_netdev_mqs(sizeof_priv, name, setup, txqs, rxqs)
+alloc_netdev_mqs(sizeof_priv, name, NET_NAME_UNKNOWN, setup, txqs, rxqs)
|
-alloc_netdev_mq(sizeof_priv, name, setup, count)
+alloc_netdev_mq(sizeof_priv, name, NET_NAME_UNKNOWN, setup, count)
|
-alloc_netdev(sizeof_priv, name, setup)
+alloc_netdev(sizeof_priv, name, NET_NAME_UNKNOWN, setup)
)

v9: move comments here from the wrong commit

Signed-off-by: Tom Gundersen <teg@jklm.no>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: fix ip_tunnel_lookup

This patch fixes 3 similar bugs where incoming packets might be routed into
wrong non-wildcard tunnels:

1) Consider the following setup:
ip address add 1.1.1.1/24 dev eth0
ip address add 1.1.1.2/24 dev eth0
ip tunnel add ipip1 remote 2.2.2.2 local 1.1.1.1 mode ipip dev eth0
ip link set ipip1 up

Incoming ipip packets from 2.2.2.2 were routed into ipip1 even if it has dst =
1.1.1.2. Moreover even if there was wildcard tunnel like
ip tunnel add ipip0 remote 2.2.2.2 local any mode ipip dev eth0
but it was created before explicit one (with local 1.1.1.1), incoming ipip
packets with src = 2.2.2.2 and dst = 1.1.1.2 were still routed into ipip1.

Same issue existed with all tunnels that use ip_tunnel_lookup (gre, vti)

2) ip address add 1.1.1.1/24 dev eth0
ip tunnel add ipip1 remote 2.2.146.85 local 1.1.1.1 mode ipip dev eth0
ip link set ipip1 up

Incoming ipip packets with dst = 1.1.1.1 were routed into ipip1, no matter what
src address is. Any remote ip address which has ip_tunnel_hash = 0 raised this
issue, 2.2.146.85 is just an example, there are more than 4 million of them.
And again, wildcard tunnel like
ip tunnel add ipip0 remote any local 1.1.1.1 mode ipip dev eth0
wouldn't be ever matched if it was created before explicit tunnel like above.

Gre & vti tunnels had the same issue.

3) ip address add 1.1.1.1/24 dev eth0
ip tunnel add gre1 remote 2.2.146.84 local 1.1.1.1 key 1 mode gre dev eth0
ip link set gre1 up

Any incoming gre packet with key = 1 were routed into gre1, no matter what
src/dst addresses are. Any remote ip address which has ip_tunnel_hash = 0 raised
the issue, 2.2.146.84 is just an example, there are more than 4 million of them.
Wildcard tunnel like
ip tunnel add gre2 remote any local any key 1 mode gre dev eth0
wouldn't be ever matched if it was created before explicit tunnel like above.

All this stuff happened because while looking for a wildcard tunnel we didn't
check that matched tunnel is a wildcard one. Fixed.

Signed-off-by: Dmitry Popov <ixaphire@qrator.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: fix dst race in sk_dst_get()

When IP route cache had been removed in linux-3.6, we broke assumption
that dst entries were all freed after rcu grace period. DST_NOCACHE
dst were supposed to be freed from dst_release(). But it appears
we want to keep such dst around, either in UDP sockets or tunnels.

In sk_dst_get() we need to make sure dst refcount is not 0
before incrementing it, or else we might end up freeing a dst
twice.

DST_NOCACHE set on a dst does not mean this dst can not be attached
to a socket or a tunnel.

Then, before actual freeing, we need to observe a rcu grace period
to make sure all other cpus can catch the fact the dst is no longer
usable.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dormando <dormando@rydia.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: fix i_key matching in ip_tunnel_find

Some tunnels (though only vti as for now) can use i_key just for internal use:
for example vti uses it for fwmark'ing incoming packets. So raw i_key value
shouldn't be treated as a distinguisher for them. ip_tunnel_key_match exists for
cases when we want to compare two ip_tunnel_parms' i_keys.

Example bug:
ip link add type vti ikey 1 local 1.0.0.1 remote 2.0.0.2
ip link add type vti ikey 2 local 1.0.0.1 remote 2.0.0.2
spawned two tunnels, although it doesn't make sense.

Signed-off-by: Dmitry Popov <ixaphire@qrator.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_vti: Fix 'ip tunnel add' with 'key' parameters

ip tunnel add remote 10.2.2.1 local 10.2.2.2 mode vti ikey 1 okey 2
translates to p->iflags = VTI_ISVTI|GRE_KEY and p->i_key = 1, but GRE_KEY !=
TUNNEL_KEY, so ip_tunnel_ioctl would set i_key to 0 (same story with o_key)
making us unable to create vti tunnels with [io]key via ip tunnel.

We cannot simply translate GRE_KEY to TUNNEL_KEY (as GRE module does) because
vti_tunnels with same local/remote addresses but different ikeys will be treated
as different then. So, imo the best option here is to move p->i_flags & *_KEY
check for vti tunnels from ip_tunnel.c to ip_vti.c and to think about [io]_mark
field for ip_tunnel_parm in the future.

Signed-off-by: Dmitry Popov <ixaphire@qrator.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: fix possible rtable leak

ip_rt_put(rt) is always called in "error" branches above, but was missed in
skb_cow_head branch. As rt is not yet bound to skb here we have to release it by
hand.

Signed-off-by: Dmitry Popov <ixaphire@qrator.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Initialize the fallback device properly

We need to initialize the fallback device to have a correct mtu
set on this device. Otherwise the mtu is set to null and the device
is unusable.

Fixes: fd58156e456d ("IPIP: Use ip-tunneling code.")
Cc: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: ip_tunnels: disable cache for nbma gre tunnels

The connected check fails to check for ip_gre nbma mode tunnels
properly. ip_gre creates temporary tnl_params with daddr specified
to pass-in the actual target on per-packet basis from neighbor
layer. Detect these tunnels by inspecting the actual tunnel
configuration.

Minimal test case:
ip route add 192.168.1.1/32 via 10.0.0.1
ip route add 192.168.1.2/32 via 10.0.0.2
ip tunnel add nbma0 mode gre key 1 tos c0
ip addr add 172.17.0.0/16 dev nbma0
ip link set nbma0 up
ip neigh add 172.17.0.1 lladdr 192.168.1.1 dev nbma0
ip neigh add 172.17.0.2 lladdr 192.168.1.2 dev nbma0
ping 172.17.0.1
ping 172.17.0.2

The second ping should be going to 192.168.1.2 and head 10.0.0.2;
but cached gre tunnel level route is used and it's actually going
to 192.168.1.1 via 10.0.0.1.

The lladdr's need to go to separate dst for the bug to trigger.
Test case uses separate route entries, but this can also happen
when the route entry is same: if there is a nexthop exception or
the GRE tunnel is IPsec'ed in which case the dst points to xfrm
bundle unique to the gre lladdr.

Fixes: 7d442fab0a67 ("ipv4: Cache dst in tunnels")
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Cc: Tom Herbert <therbert@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: don't add tunnel twice

When using command "ip tunnel add" to add a tunnel, the tunnel will be added twice,
through ip_tunnel_create() and ip_tunnel_update().

Because the second is unnecessary, so we can just break after adding tunnel
through ip_tunnel_create().

Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: delete unneeded call to netdev_priv

Netdev_priv is an accessor function, and has no purpose if its result is
not used.

A simplified version of the semantic match that fixes this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@ local idexpression x; @@
-x = netdev_priv(...);
... when != x
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Set network header properly for IP_ECN_decapsulate()

In ip_tunnel_rcv(), set skb->network_header to inner IP header
before IP_ECN_decapsulate().

Without the fix, IP_ECN_decapsulate() takes outer IP header as
inner IP header, possibly causing error messages or packet drops.

Note that this skb_reset_network_header() call was in this spot when
the original feature for checking consistency of ECN bits through
tunnels was added in eccc1bb8d4b4 ("tunnel: drop packet if ECN present
with not-ECT"). It was only removed from this spot in 3d7b46cd20e3
("ip_tunnel: push generic protocol handling to ip_tunnel module.").

Fixes: 3d7b46cd20e3 ("ip_tunnel: push generic protocol handling to ip_tunnel module.")
Reported-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Ying Cai <ycai@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: use the right netns in ioctl handler

Because the netdevice may be in another netns than the i/o netns, we should
use the i/o netns instead of dev_net(dev).

The variable 'tunnel' was used only to get 'itn', hence to simplify code I
remove it and use 't' instead.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: add a sock pointer to dst->output() path.

In the dst->output() path for ipv4, the code assumes the skb it has to
transmit is attached to an inet socket, specifically via
ip_mc_output() : The sk_mc_loop() test triggers a WARN_ON() when the
provider of the packet is an AF_PACKET socket.

The dst->output() method gets an additional 'struct sock *sk'
parameter. This needs a cascade of changes so that this parameter can
be propagated from vxlan to final consumer.

Fixes: 8f646c922d55 ("vxlan: keep original skb ownership")
Reported-by: lucien xin <lucien.xin@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Fix dst ref-count.

Commit 10ddceb22ba (ip_tunnel:multicast process cause panic due
to skb->_skb_refdst NULL pointer) removed dst-drop call from
ip-tunnel-recv.

Following commit reintroduce dst-drop and fix the original bug by
checking loopback packet before releasing dst.
Original bug: https://bugzilla.kernel.org/show_bug.cgi?id=70681

CC: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Make vti work with i_key set

Vti uses the o_key to mark packets that were transmitted or received
by a vti interface. Unfortunately we can't apply different marks
to in and outbound packets with only one key availabe. Vti interfaces
typically use wildcard selectors for vti IPsec policies. On forwarding,
the same output policy will match for both directions. This generates
a loop between the IPsec gateways until the ttl of the packet is
exceeded.

The gre i_key/o_key are usually there to find the right gre tunnel
during a lookup. When vti uses the i_key to mark packets, the tunnel
lookup does not work any more because vti does not use the gre keys
as a hash key for the lookup.

This patch workarounds this my not including the i_key when comupting
the hash for the tunnel lookup in case of vti tunnels.

With this we have separate keys available for the transmitting and
receiving side of the vti interface.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

sit: fix panic with route cache in ip tunnels

Bug introduced by commit 7d442fab0a67 ("ipv4: Cache dst in tunnels").

Because sit code does not call ip_tunnel_init(), the dst_cache was not
initialized.

CC: Tom Herbert <therbert@google.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Move ip_tunnel_get_stats64 into ip_tunnel_core.c

net/built-in.o:(.rodata+0x1707c): undefined reference to `ip_tunnel_get_stats64'

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: return more precise errno value when adding tunnel fails

Currently this always returns ENOBUFS, because the return value of
__ip_tunnel_create is discarded.

A more common failure is a duplicate name (EEXIST). Propagate the real
error code so userspace can display a more meaningful error message.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: introduce netdev_alloc_pcpu_stats() for drivers

There are many drivers calling alloc_percpu() to allocate pcpu stats
and then initializing ->syncp. So just introduce a helper function for them.

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: fix panic in ip_tunnel_xmit()

Setting rt variable to NULL at the beginning of ip_tunnel_xmit()
missed possible use of this variable as a scratch value.

Also fixes a possible dst leak in tunnel_dst_check() :
If we had to call tunnel_dst_reset(), we forgot to
release the reference on dst.

Merges tunnel_dst_get()/tunnel_dst_check() into
a single tunnel_rtable_get() function for clarity.

Many thanks to Tommi for his report and tests.

Fixes: 7d442fab0a67 ("ipv4: Cache dst in tunnels")
Reported-by: Tommi Rantala <tt.rantala@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Tommi Rantala <tt.rantala@gmail.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Maciej Żenczykowski <maze@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipv4: Use PTR_ERR_OR_ZERO

PTR_RET is deprecated. Use PTR_ERR_OR_ZERO instead. While at it
also include missing err.h header.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: clear IPCB in ip_tunnel_xmit() in case dst_link_failure() is called

commit a622260254ee48("ip_tunnel: fix kernel panic with icmp_dest_unreach")
clear IPCB in ip_tunnel_xmit() , or else skb->cb[] may contain garbage from
GSO segmentation layer.

But commit 0e6fbc5b6c621("ip_tunnels: extend iptunnel_xmit()") refactor codes,
and it clear IPCB behind the dst_link_failure().

So clear IPCB in ip_tunnel_xmit() just like commti a622260254ee48("ip_tunnel:
fix kernel panic with icmp_dest_unreach").

Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: remove the useless argument from ip_tunnel_hash()

Since commit c544193214("GRE: Refactor GRE tunneling code")
introduced function ip_tunnel_hash(), the argument itn is no
longer in use, so remove it.

Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: be friend with drop monitor

Replace some dev_kfree_skb() with kfree_skb() calls when
we drop one skb, this might help bug tracking.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: fix a dst leak in tunnels

This patch :

1) Remove a dst leak if DST_NOCACHE was set on dst
Fix this by holding a reference only if dst really cached.

2) Remove a lockdep warning in __tunnel_dst_set()
This was reported by Cong Wang.

3) Remove usage of a spinlock where xchg() is enough

4) Remove some spurious inline keywords.
Let compiler decide for us.

Fixes: 7d442fab0a67 ("ipv4: Cache dst in tunnels")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Cong Wang <cwang@twopensource.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Maciej Żenczykowski <maze@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: fix sparse non static symbol warning

Fixes the following sparse warning:

net/ipv4/ip_tunnel.c:116:18: warning:
symbol 'tunnel_dst_check' was not declared. Should it be static?

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: unify the pcpu_tstats and br_cpu_netstats as one

They are same, so unify them as one, pcpu_sw_netstats.

Define pcpu_sw_netstat in netdevice.h, remove pcpu_tstats
from if_tunnel and remove br_cpu_netstats from br_private.h

Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: Use percpu Cache route in IP tunnels

percpu route cache eliminates share of dst refcnt between CPUs.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: Cache dst in tunnels

Avoid doing a route lookup on every packet being tunneled.

In ip_tunnel.c cache the route returned from ip_route_output if
the tunnel is "connected" so that all the rouitng parameters are
taken from tunnel parms for a packet. Specifically, not NBMA tunnel
and tos is from tunnel parms (not inner packet).

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

core/dev: do not ignore dmac in dev_forward_skb()

commit 06a23fe31ca3
("core/dev: set pkt_type after eth_type_trans() in dev_forward_skb()")
and refactoring 64261f230a91
("dev: move skb_scrub_packet() after eth_type_trans()")

are forcing pkt_type to be PACKET_HOST when skb traverses veth.

which means that ip forwarding will kick in inside netns
even if skb->eth->h_dest != dev->dev_addr

Fix order of eth_type_trans() and skb_scrub_packet() in dev_forward_skb()
and in ip_tunnel_rcv()

Fixes: 06a23fe31ca3 ("core/dev: set pkt_type after eth_type_trans() in dev_forward_skb()")
CC: Isaku Yamahata <yamahatanetdev@gmail.com>
CC: Maciej Zenczykowski <zenczykowski@gmail.com>
CC: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Explicitly initialize u64_stats_sync structures for lockdep

In order to enable lockdep on seqcount/seqlock structures, we
must explicitly initialize any locks.

The u64_stats_sync structure, uses a seqcount, and thus we need
to introduce a u64_stats_init() function and use it to initialize
the structure.

This unfortunately adds a lot of fairly trivial initialization code
to a number of drivers. But the benefit of ensuring correctness makes
this worth while.

Because these changes are required for lockdep to be enabled, and the
changes are quite trivial, I've not yet split this patch out into 30-some
separate patches, as I figured it would be better to get the various
maintainers thoughts on how to best merge this change along with
the seqcount lockdep enablement.

Feedback would be appreciated!

Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: James Morris <jmorris@namei.org>
Cc: Jesse Gross <jesse@nicira.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mirko Lindner <mlindner@marvell.com>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Roger Luethi <rl@hellgate.ch>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Simon Horman <horms@verge.net.au>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Wensong Zhang <wensong@linux-vs.org>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/1381186321-4906-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

ip_tunnel: Remove double unregister of the fallback device

When queueing the netdevices for removal, we queue the
fallback device twice in ip_tunnel_destroy(). The first
time when we queue all netdevices in the namespace and
then again explicitly. Fix this by removing the explicit
queueing of the fallback device.

Bug was introduced when network namespace support was added
with commit 6c742e714d8 ("ipip: add x-netns support").

Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Add fallback tunnels to the hash lists

Currently we can not update the tunnel parameters of
the fallback tunnels because we don't find them in the
hash lists. Fix this by adding them on initialization.

Bug was introduced with commit c544193214
("GRE: Refactor GRE tunneling code.")

Cc: Pravin Shelar <pshelar@nicira.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Fix a memory corruption in ip_tunnel_xmit

We might extend the used aera of a skb beyond the total
headroom when we install the ipip header. Fix this by
calling skb_cow_head() unconditionally.

Bug was introduced with commit c544193214
("GRE: Refactor GRE tunneling code.")

Cc: Pravin Shelar <pshelar@nicira.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Do not use stale inner_iph pointer.

While sending packet skb_cow_head() can change skb header which
invalidates inner_iph pointer to skb header. Following patch
avoid using it. Found by code inspection.

This bug was introduced by commit 0e6fbc5b6c6218 (ip_tunnels: extend
iptunnel_xmit()).

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tunnels: harmonize cleanup done on skb on rx path

The goal of this patch is to harmonize cleanup done on a skbuff on rx path.
Before this patch, behaviors were different depending of the tunnel type.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tunnels: harmonize cleanup done on skb on xmit path

The goal of this patch is to harmonize cleanup done on a skbuff on xmit path.
Before this patch, behaviors were different depending of the tunnel type.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

skb: allow skb_scrub_packet() to be used by tunnels

This function was only used when a packet was sent to another netns. Now, it can
also be used after tunnel encapsulation or decapsulation.

Only skb_orphan() should not be done when a packet is not crossing netns.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

iptunnels: remove net arg from iptunnel_xmit()

This argument is not used, let's remove it.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipip: potential race in ip_tunnel_init_net()

Eric Dumazet says that my previous fix for an ERR_PTR dereference
(ea857f28ab 'ipip: dereferencing an ERR_PTR in ip_tunnel_init_net()')
could be racy and suggests the following fix instead.

Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipip: dereferencing an ERR_PTR in ip_tunnel_init_net()

We need to move the derefernce after the IS_ERR() check.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipip: add x-netns support

This patch allows to switch the netns when packet is encapsulated or
decapsulated. In other word, the encapsulated packet is received in a netns,
where the lookup is done to find the tunnel. Once the tunnel is found, the
packet is decapsulated and injecting into the corresponding interface which
stands to another netns.

When one of the two netns is removed, the tunnel is destroyed.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4 tunnels: use net_eq() helper to check netns

It's better to use available helpers for these tests.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

dev: move skb_scrub_packet() after eth_type_trans()

skb_scrub_packet() was called before eth_type_trans() to let eth_type_trans()
set pkt_type.

In fact, we should force pkt_type to PACKET_HOST, so move the call after
eth_type_trans().

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: embed hash list head

The IP tunnel hash heads can be embedded in the per-net structure
since it is a fixed size. Reduce the size so that the total structure
fits in a page size. The original size was overly large, even NETDEV_HASHBITS
is only 8 bits!

Also, add some white space for readability.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Pravin B Shelar <pshelar@nicira.com>.
Signed-off-by: David S. Miller <davem@davemloft.net>

gre: Fix MTU sizing check for gretap tunnels

This change fixes an MTU sizing issue seen with gretap tunnels when non-gso
packets are sent from the interface.

In my case I was able to reproduce the issue by simply sending a ping of
1421 bytes with the gretap interface created on a device with a standard
1500 mtu.

This fix is based on the fact that the tunnel mtu is already adjusted by
dev->hard_header_len so it would make sense that any packets being compared
against that mtu should also be adjusted by hard_header_len and the tunnel
header instead of just the tunnel header.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Reported-by: Cong Wang <amwang@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnels: Use skb-len to PMTU check.

In path mtu check, ip header total length works for gre device
but not for gre-tap device. Use skb len which is consistent
for all tunneling types. This is old bug in gre.
This also fixes mtu calculation bug introduced by
commit c54419321455631079c7d (GRE: Refactor GRE tunneling code).

Reported-by: Timo Teras <timo.teras@iki.fi>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sit: add support of x-netns

This patch allows to switch the netns when packet is encapsulated or
decapsulated. In other word, the encapsulated packet is received in a netns,
where the lookup is done to find the tunnel. Once the tunnel is found, the
packet is decapsulated and injecting into the corresponding interface which
stands to another netns.

When one of the two netns is removed, the tunnel is destroyed.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sit: fix 4in4 + IPsec scenario

Since commit 32b8a8e59c9c "sit: add IPv4 over IPv4 support",
tunnel->parms.iph.protocol is 0 when both 4in4 and 6in4 are setup, but
xfrm_lookup() is called only when proto is != 0, thus we need to pass the real
value.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: push generic protocol handling to ip_tunnel module.

Process skb tunnel header before sending packet to protocol handler.
this allows code sharing between gre and ovs gre modules.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnels: extend iptunnel_xmit()

Refactor various ip tunnels xmit functions and extend iptunnel_xmit()
so that there is more code sharing.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: remove __net_init/exit from exported functions

If CONFIG_NET_NS is not set then __net_init is the same as __init and
__net_exit is the same as __exit. These functions will be removed from
memory after the module loads or is removed. Functions that are exported
for use by other functions should never be labeled for removal.

Bug introduced by commit c54419321455631079c
("GRE: Refactor GRE tunneling code.")

Reported-by: Steinar H. Gunderson <sgunderson@bigfoot.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

iptunnel: specify protocol outside IP header

Before this patch, ip_tunnel_xmit() was using the field protocol from the IP
header passed into argument.
There is no functional change, this patch prepares the support of IPv4 over
IPv4 for module sit.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: fix kernel panic with icmp_dest_unreach

Daniel Petre reported crashes in icmp_dst_unreach() with following call
graph:

#3 [ffff88003fc03938] __stack_chk_fail at ffffffff81037f77
#4 [ffff88003fc03948] icmp_send at ffffffff814d5fec
#5 [ffff88003fc03ae8] ipv4_link_failure at ffffffff814a1795
#6 [ffff88003fc03af8] ipgre_tunnel_xmit at ffffffff814e7965
#7 [ffff88003fc03b78] dev_hard_start_xmit at ffffffff8146e032
#8 [ffff88003fc03bc8] sch_direct_xmit at ffffffff81487d66
#9 [ffff88003fc03c08] __qdisc_run at ffffffff81487efd
#10 [ffff88003fc03c48] dev_queue_xmit at ffffffff8146e5a7
#11 [ffff88003fc03c88] ip_finish_output at ffffffff814ab596

Daniel found a similar problem mentioned in
http://lkml.indiana.edu/hypermail/linux/kernel/1007.0/00961.html

And indeed this is the root cause : skb->cb[] contains data fooling IP
stack.

We must clear IPCB in ip_tunnel_xmit() sooner in case dst_link_failure()
is called. Or else skb->cb[] might contain garbage from GSO segmentation
layer.

A similar fix was tested on linux-3.9, but gre code was refactored in
linux-3.10. I'll send patches for stable kernels as well.

Many thanks to Daniel for providing reports, patches and testing !

Reported-by: Daniel Petre <daniel.petre@rcs-rds.ro>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip_tunnel: Fix off-by-one error in forming dev name.

As Ben pointed out following patch fixes bug in checking device
name length limits while forming tunnel device name.

CC: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

GRE: Refactor GRE tunneling code.

Following patch refactors GRE code into ip tunneling code and GRE
specific code. Common tunneling code is moved to ip_tunnel module.
ip_tunnel module is written as generic library which can be used
by different tunneling implementations.

ip_tunnel module contains following components:
- packet xmit and rcv generic code. xmit flow looks like
(gre_xmit/ipip_xmit)->ip_tunnel_xmit->ip_local_out.
- hash table of all devices.
- lookup for tunnel devices.
- control plane operations like device create, destroy, ioctl, netlink
operations code.
- registration for tunneling modules, like gre, ipip etc.
- define single pcpu_tstats dev->tstats.
- struct tnl_ptk_info added to pass parsed tunnel packet parameters.

ipip.h header is renamed to ip_tunnel.h

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>