ipvlan: add ipvlan_route_v6_outbound() helper

Inspired by syzbot reports using a stack of multiple ipvlan devices.

Reduce stack size needed in ipvlan_process_v6_outbound() by moving
the flowi6 struct used for the route lookup in an non inlined
helper. ipvlan_route_v6_outbound() needs 120 bytes on the stack,
immediately reclaimed.

Also make sure ipvlan_process_v4_outbound() is not inlined.

We might also have to lower MAX_NEST_DEV, because only syzbot uses
setups with more than four stacked devices.

BUG: TASK stack guard page was hit at ffffc9000e803ff8 (stack is ffffc9000e804000..ffffc9000e808000)
stack guard page: 0000 [#1] SMP KASAN
CPU: 0 PID: 13442 Comm: syz-executor.4 Not tainted 6.1.52-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
RIP: 0010:kasan_check_range+0x4/0x2a0 mm/kasan/generic.c:188
Code: 48 01 c6 48 89 c7 e8 db 4e c1 03 31 c0 5d c3 cc 0f 0b eb 02 0f 0b b8 ea ff ff ff 5d c3 cc 00 00 cc cc 00 00 cc cc 55 48 89 e5 <41> 57 41 56 41 55 41 54 53 b0 01 48 85 f6 0f 84 a4 01 00 00 48 89
RSP: 0018:ffffc9000e804000 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff817e5bf2
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff887c6568
RBP: ffffc9000e804000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92001d0080c
R13: dffffc0000000000 R14: ffffffff87e6b100 R15: 0000000000000000
FS: 00007fd0c55826c0(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc9000e803ff8 CR3: 0000000170ef7000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<#DF>
</#DF>
<TASK>
[<ffffffff81f281d1>] __kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31
[<ffffffff817e5bf2>] instrument_atomic_read include/linux/instrumented.h:72 [inline]
[<ffffffff817e5bf2>] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
[<ffffffff817e5bf2>] cpumask_test_cpu include/linux/cpumask.h:506 [inline]
[<ffffffff817e5bf2>] cpu_online include/linux/cpumask.h:1092 [inline]
[<ffffffff817e5bf2>] trace_lock_acquire include/trace/events/lock.h:24 [inline]
[<ffffffff817e5bf2>] lock_acquire+0xe2/0x590 kernel/locking/lockdep.c:5632
[<ffffffff8563221e>] rcu_lock_acquire+0x2e/0x40 include/linux/rcupdate.h:306
[<ffffffff8561464d>] rcu_read_lock include/linux/rcupdate.h:747 [inline]
[<ffffffff8561464d>] ip6_pol_route+0x15d/0x1440 net/ipv6/route.c:2221
[<ffffffff85618120>] ip6_pol_route_output+0x50/0x80 net/ipv6/route.c:2606
[<ffffffff856f65b5>] pol_lookup_func include/net/ip6_fib.h:584 [inline]
[<ffffffff856f65b5>] fib6_rule_lookup+0x265/0x620 net/ipv6/fib6_rules.c:116
[<ffffffff85618009>] ip6_route_output_flags_noref+0x2d9/0x3a0 net/ipv6/route.c:2638
[<ffffffff8561821a>] ip6_route_output_flags+0xca/0x340 net/ipv6/route.c:2651
[<ffffffff838bd5a3>] ip6_route_output include/net/ip6_route.h:100 [inline]
[<ffffffff838bd5a3>] ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:473 [inline]
[<ffffffff838bd5a3>] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:529 [inline]
[<ffffffff838bd5a3>] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
[<ffffffff838bd5a3>] ipvlan_queue_xmit+0xc33/0x1be0 drivers/net/ipvlan/ipvlan_core.c:677
[<ffffffff838c2909>] ipvlan_start_xmit+0x49/0x100 drivers/net/ipvlan/ipvlan_main.c:229
[<ffffffff84d03900>] netdev_start_xmit include/linux/netdevice.h:4966 [inline]
[<ffffffff84d03900>] xmit_one net/core/dev.c:3644 [inline]
[<ffffffff84d03900>] dev_hard_start_xmit+0x320/0x980 net/core/dev.c:3660
[<ffffffff84d080e2>] __dev_queue_xmit+0x16b2/0x3370 net/core/dev.c:4324
[<ffffffff855ce4cd>] dev_queue_xmit include/linux/netdevice.h:3067 [inline]
[<ffffffff855ce4cd>] neigh_hh_output include/net/neighbour.h:529 [inline]
[<ffffffff855ce4cd>] neigh_output include/net/neighbour.h:543 [inline]
[<ffffffff855ce4cd>] ip6_finish_output2+0x160d/0x1ae0 net/ipv6/ip6_output.c:139
[<ffffffff855b8616>] __ip6_finish_output net/ipv6/ip6_output.c:200 [inline]
[<ffffffff855b8616>] ip6_finish_output+0x6c6/0xb10 net/ipv6/ip6_output.c:211
[<ffffffff855b7e3c>] NF_HOOK_COND include/linux/netfilter.h:298 [inline]
[<ffffffff855b7e3c>] ip6_output+0x2bc/0x3d0 net/ipv6/ip6_output.c:232
[<ffffffff8575d27f>] dst_output include/net/dst.h:444 [inline]
[<ffffffff8575d27f>] ip6_local_out+0x10f/0x140 net/ipv6/output_core.c:161
[<ffffffff838bdae4>] ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:483 [inline]
[<ffffffff838bdae4>] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:529 [inline]
[<ffffffff838bdae4>] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
[<ffffffff838bdae4>] ipvlan_queue_xmit+0x1174/0x1be0 drivers/net/ipvlan/ipvlan_core.c:677
[<ffffffff838c2909>] ipvlan_start_xmit+0x49/0x100 drivers/net/ipvlan/ipvlan_main.c:229
[<ffffffff84d03900>] netdev_start_xmit include/linux/netdevice.h:4966 [inline]
[<ffffffff84d03900>] xmit_one net/core/dev.c:3644 [inline]
[<ffffffff84d03900>] dev_hard_start_xmit+0x320/0x980 net/core/dev.c:3660
[<ffffffff84d080e2>] __dev_queue_xmit+0x16b2/0x3370 net/core/dev.c:4324
[<ffffffff855ce4cd>] dev_queue_xmit include/linux/netdevice.h:3067 [inline]
[<ffffffff855ce4cd>] neigh_hh_output include/net/neighbour.h:529 [inline]
[<ffffffff855ce4cd>] neigh_output include/net/neighbour.h:543 [inline]
[<ffffffff855ce4cd>] ip6_finish_output2+0x160d/0x1ae0 net/ipv6/ip6_output.c:139
[<ffffffff855b8616>] __ip6_finish_output net/ipv6/ip6_output.c:200 [inline]
[<ffffffff855b8616>] ip6_finish_output+0x6c6/0xb10 net/ipv6/ip6_output.c:211
[<ffffffff855b7e3c>] NF_HOOK_COND include/linux/netfilter.h:298 [inline]
[<ffffffff855b7e3c>] ip6_output+0x2bc/0x3d0 net/ipv6/ip6_output.c:232
[<ffffffff8575d27f>] dst_output include/net/dst.h:444 [inline]
[<ffffffff8575d27f>] ip6_local_out+0x10f/0x140 net/ipv6/output_core.c:161
[<ffffffff838bdae4>] ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:483 [inline]
[<ffffffff838bdae4>] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:529 [inline]
[<ffffffff838bdae4>] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
[<ffffffff838bdae4>] ipvlan_queue_xmit+0x1174/0x1be0 drivers/net/ipvlan/ipvlan_core.c:677
[<ffffffff838c2909>] ipvlan_start_xmit+0x49/0x100 drivers/net/ipvlan/ipvlan_main.c:229
[<ffffffff84d03900>] netdev_start_xmit include/linux/netdevice.h:4966 [inline]
[<ffffffff84d03900>] xmit_one net/core/dev.c:3644 [inline]
[<ffffffff84d03900>] dev_hard_start_xmit+0x320/0x980 net/core/dev.c:3660
[<ffffffff84d080e2>] __dev_queue_xmit+0x16b2/0x3370 net/core/dev.c:4324
[<ffffffff855ce4cd>] dev_queue_xmit include/linux/netdevice.h:3067 [inline]
[<ffffffff855ce4cd>] neigh_hh_output include/net/neighbour.h:529 [inline]
[<ffffffff855ce4cd>] neigh_output include/net/neighbour.h:543 [inline]
[<ffffffff855ce4cd>] ip6_finish_output2+0x160d/0x1ae0 net/ipv6/ip6_output.c:139
[<ffffffff855b8616>] __ip6_finish_output net/ipv6/ip6_output.c:200 [inline]
[<ffffffff855b8616>] ip6_finish_output+0x6c6/0xb10 net/ipv6/ip6_output.c:211
[<ffffffff855b7e3c>] NF_HOOK_COND include/linux/netfilter.h:298 [inline]
[<ffffffff855b7e3c>] ip6_output+0x2bc/0x3d0 net/ipv6/ip6_output.c:232
[<ffffffff8575d27f>] dst_output include/net/dst.h:444 [inline]
[<ffffffff8575d27f>] ip6_local_out+0x10f/0x140 net/ipv6/output_core.c:161
[<ffffffff838bdae4>] ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:483 [inline]
[<ffffffff838bdae4>] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:529 [inline]
[<ffffffff838bdae4>] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
[<ffffffff838bdae4>] ipvlan_queue_xmit+0x1174/0x1be0 drivers/net/ipvlan/ipvlan_core.c:677
[<ffffffff838c2909>] ipvlan_start_xmit+0x49/0x100 drivers/net/ipvlan/ipvlan_main.c:229
[<ffffffff84d03900>] netdev_start_xmit include/linux/netdevice.h:4966 [inline]
[<ffffffff84d03900>] xmit_one net/core/dev.c:3644 [inline]
[<ffffffff84d03900>] dev_hard_start_xmit+0x320/0x980 net/core/dev.c:3660
[<ffffffff84d080e2>] __dev_queue_xmit+0x16b2/0x3370 net/core/dev.c:4324
[<ffffffff855ce4cd>] dev_queue_xmit include/linux/netdevice.h:3067 [inline]
[<ffffffff855ce4cd>] neigh_hh_output include/net/neighbour.h:529 [inline]
[<ffffffff855ce4cd>] neigh_output include/net/neighbour.h:543 [inline]
[<ffffffff855ce4cd>] ip6_finish_output2+0x160d/0x1ae0 net/ipv6/ip6_output.c:139
[<ffffffff855b8616>] __ip6_finish_output net/ipv6/ip6_output.c:200 [inline]
[<ffffffff855b8616>] ip6_finish_output+0x6c6/0xb10 net/ipv6/ip6_output.c:211
[<ffffffff855b7e3c>] NF_HOOK_COND include/linux/netfilter.h:298 [inline]
[<ffffffff855b7e3c>] ip6_output+0x2bc/0x3d0 net/ipv6/ip6_output.c:232
[<ffffffff8575d27f>] dst_output include/net/dst.h:444 [inline]
[<ffffffff8575d27f>] ip6_local_out+0x10f/0x140 net/ipv6/output_core.c:161
[<ffffffff838bdae4>] ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:483 [inline]
[<ffffffff838bdae4>] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:529 [inline]
[<ffffffff838bdae4>] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
[<ffffffff838bdae4>] ipvlan_queue_xmit+0x1174/0x1be0 drivers/net/ipvlan/ipvlan_core.c:677
[<ffffffff838c2909>] ipvlan_start_xmit+0x49/0x100 drivers/net/ipvlan/ipvlan_main.c:229
[<ffffffff84d03900>] netdev_start_xmit include/linux/netdevice.h:4966 [inline]
[<ffffffff84d03900>] xmit_one net/core/dev.c:3644 [inline]
[<ffffffff84d03900>] dev_hard_start_xmit+0x320/0x980 net/core/dev.c:3660
[<ffffffff84d080e2>] __dev_queue_xmit+0x16b2/0x3370 net/core/dev.c:4324
[<ffffffff84d4a65e>] dev_queue_xmit include/linux/netdevice.h:3067 [inline]
[<ffffffff84d4a65e>] neigh_resolve_output+0x64e/0x750 net/core/neighbour.c:1560
[<ffffffff855ce503>] neigh_output include/net/neighbour.h:545 [inline]
[<ffffffff855ce503>] ip6_finish_output2+0x1643/0x1ae0 net/ipv6/ip6_output.c:139
[<ffffffff855b8616>] __ip6_finish_output net/ipv6/ip6_output.c:200 [inline]
[<ffffffff855b8616>] ip6_finish_output+0x6c6/0xb10 net/ipv6/ip6_output.c:211
[<ffffffff855b7e3c>] NF_HOOK_COND include/linux/netfilter.h:298 [inline]
[<ffffffff855b7e3c>] ip6_output+0x2bc/0x3d0 net/ipv6/ip6_output.c:232
[<ffffffff855b9ce4>] dst_output include/net/dst.h:444 [inline]
[<ffffffff855b9ce4>] NF_HOOK include/linux/netfilter.h:309 [inline]
[<ffffffff855b9ce4>] ip6_xmit+0x11a4/0x1b20 net/ipv6/ip6_output.c:352
[<ffffffff8597984e>] sctp_v6_xmit+0x9ae/0x1230 net/sctp/ipv6.c:250
[<ffffffff8594623e>] sctp_packet_transmit+0x25de/0x2bc0 net/sctp/output.c:653
[<ffffffff858f5142>] sctp_packet_singleton+0x202/0x310 net/sctp/outqueue.c:783
[<ffffffff858ea411>] sctp_outq_flush_ctrl net/sctp/outqueue.c:914 [inline]
[<ffffffff858ea411>] sctp_outq_flush+0x661/0x3d40 net/sctp/outqueue.c:1212
[<ffffffff858f02f9>] sctp_outq_uncork+0x79/0xb0 net/sctp/outqueue.c:764
[<ffffffff8589f060>] sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline]
[<ffffffff8589f060>] sctp_do_sm+0x55c0/0x5c30 net/sctp/sm_sideeffect.c:1170
[<ffffffff85941567>] sctp_primitive_ASSOCIATE+0x97/0xc0 net/sctp/primitive.c:73
[<ffffffff859408b2>] sctp_sendmsg_to_asoc+0xf62/0x17b0 net/sctp/socket.c:1839
[<ffffffff85910b5e>] sctp_sendmsg+0x212e/0x33b0 net/sctp/socket.c:2029
[<ffffffff8544d559>] inet_sendmsg+0x149/0x310 net/ipv4/af_inet.c:849
[<ffffffff84c6c4d2>] sock_sendmsg_nosec net/socket.c:716 [inline]
[<ffffffff84c6c4d2>] sock_sendmsg net/socket.c:736 [inline]
[<ffffffff84c6c4d2>] ____sys_sendmsg+0x572/0x8c0 net/socket.c:2504
[<ffffffff84c6ca91>] ___sys_sendmsg net/socket.c:2558 [inline]
[<ffffffff84c6ca91>] __sys_sendmsg+0x271/0x360 net/socket.c:2587
[<ffffffff84c6cbff>] __do_sys_sendmsg net/socket.c:2596 [inline]
[<ffffffff84c6cbff>] __se_sys_sendmsg net/socket.c:2594 [inline]
[<ffffffff84c6cbff>] __x64_sys_sendmsg+0x7f/0x90 net/socket.c:2594
[<ffffffff85b32553>] do_syscall_x64 arch/x86/entry/common.c:51 [inline]
[<ffffffff85b32553>] do_syscall_64+0x53/0x80 arch/x86/entry/common.c:84
[<ffffffff85c00087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: properly track tx_errors

Both ipvlan_process_v4_outbound() and ipvlan_process_v6_outbound()
increment dev->stats.tx_errors in case of errors.

Unfortunately there are two issues :

1) ipvlan_get_stats64() does not propagate dev->stats.tx_errors to user.

2) Increments are not atomic. KCSAN would complain eventually.

Use DEV_STATS_INC() to not miss an update, and change ipvlan_get_stats64()
to copy the value back to user.

Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Link: https://lore.kernel.org/r/20231026131446.3933175-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipvlan: Fix return value of ipvlan_queue_xmit()

ipvlan_queue_xmit() should return NET_XMIT_XXX, but
ipvlan_xmit_mode_l2/l3() returns rx_handler_result_t or NET_RX_XXX
in some cases. ipvlan_rcv_frame() will only return RX_HANDLER_CONSUMED
in ipvlan_xmit_mode_l2/l3() because 'local' is true. It's equal to
NET_XMIT_SUCCESS. But dev_forward_skb() can return NET_RX_SUCCESS or
NET_RX_DROP, and returning NET_RX_DROP(NET_XMIT_DROP) will increase
both ipvlan and ipvlan->phy_dev drops counter.

The skb to forward can be treated as xmitted successfully. This patch
makes ipvlan_queue_xmit() return NET_XMIT_SUCCESS for forward skb.

Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.")
Signed-off-by: Cambda Zhu <cambda@linux.alibaba.com>
Link: https://lore.kernel.org/r/20230626093347.7492-1-cambda@linux.alibaba.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

ipvlan: Remove NULL check before dev_{put, hold}

The call netdev_{put, hold} of dev_{put, hold} will check NULL,
so there is no need to check before using dev_{put, hold},
remove it to silence the warning:

./drivers/net/ipvlan/ipvlan_core.c:559:3-11: WARNING: NULL check before dev_{put, hold} functions is not needed.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=4930
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan:Fix out-of-bounds caused by unclear skb->cb

If skb enqueue the qdisc, fq_skb_cb(skb)->time_to_send is changed which
is actually skb->cb, and IPCB(skb_in)->opt will be used in
__ip_options_echo. It is possible that memcpy is out of bounds and lead
to stack overflow.
We should clear skb->cb before ip_local_out or ip6_local_out.

v2:
1. clean the stack info
2. use IPCB/IP6CB instead of skb->cb

crash on stable-5.10(reproduce in kasan kernel).
Stack info:
[ 2203.651571] BUG: KASAN: stack-out-of-bounds in
__ip_options_echo+0x589/0x800
[ 2203.653327] Write of size 4 at addr ffff88811a388f27 by task
swapper/3/0
[ 2203.655460] CPU: 3 PID: 0 Comm: swapper/3 Kdump: loaded Not tainted
5.10.0-60.18.0.50.h856.kasan.eulerosv2r11.x86_64 #1
[ 2203.655466] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.10.2-0-g5f4c7b1-20181220_000000-szxrtosci10000 04/01/2014
[ 2203.655475] Call Trace:
[ 2203.655481] <IRQ>
[ 2203.655501] dump_stack+0x9c/0xd3
[ 2203.655514] print_address_description.constprop.0+0x19/0x170
[ 2203.655530] __kasan_report.cold+0x6c/0x84
[ 2203.655586] kasan_report+0x3a/0x50
[ 2203.655594] check_memory_region+0xfd/0x1f0
[ 2203.655601] memcpy+0x39/0x60
[ 2203.655608] __ip_options_echo+0x589/0x800
[ 2203.655654] __icmp_send+0x59a/0x960
[ 2203.655755] nf_send_unreach+0x129/0x3d0 [nf_reject_ipv4]
[ 2203.655763] reject_tg+0x77/0x1bf [ipt_REJECT]
[ 2203.655772] ipt_do_table+0x691/0xa40 [ip_tables]
[ 2203.655821] nf_hook_slow+0x69/0x100
[ 2203.655828] __ip_local_out+0x21e/0x2b0
[ 2203.655857] ip_local_out+0x28/0x90
[ 2203.655868] ipvlan_process_v4_outbound+0x21e/0x260 [ipvlan]
[ 2203.655931] ipvlan_xmit_mode_l3+0x3bd/0x400 [ipvlan]
[ 2203.655967] ipvlan_queue_xmit+0xb3/0x190 [ipvlan]
[ 2203.655977] ipvlan_start_xmit+0x2e/0xb0 [ipvlan]
[ 2203.655984] xmit_one.constprop.0+0xe1/0x280
[ 2203.655992] dev_hard_start_xmit+0x62/0x100
[ 2203.656000] sch_direct_xmit+0x215/0x640
[ 2203.656028] __qdisc_run+0x153/0x1f0
[ 2203.656069] __dev_queue_xmit+0x77f/0x1030
[ 2203.656173] ip_finish_output2+0x59b/0xc20
[ 2203.656244] __ip_finish_output.part.0+0x318/0x3d0
[ 2203.656312] ip_finish_output+0x168/0x190
[ 2203.656320] ip_output+0x12d/0x220
[ 2203.656357] __ip_queue_xmit+0x392/0x880
[ 2203.656380] __tcp_transmit_skb+0x1088/0x11c0
[ 2203.656436] __tcp_retransmit_skb+0x475/0xa30
[ 2203.656505] tcp_retransmit_skb+0x2d/0x190
[ 2203.656512] tcp_retransmit_timer+0x3af/0x9a0
[ 2203.656519] tcp_write_timer_handler+0x3ba/0x510
[ 2203.656529] tcp_write_timer+0x55/0x180
[ 2203.656542] call_timer_fn+0x3f/0x1d0
[ 2203.656555] expire_timers+0x160/0x200
[ 2203.656562] run_timer_softirq+0x1f4/0x480
[ 2203.656606] __do_softirq+0xfd/0x402
[ 2203.656613] asm_call_irq_on_stack+0x12/0x20
[ 2203.656617] </IRQ>
[ 2203.656623] do_softirq_own_stack+0x37/0x50
[ 2203.656631] irq_exit_rcu+0x134/0x1a0
[ 2203.656639] sysvec_apic_timer_interrupt+0x36/0x80
[ 2203.656646] asm_sysvec_apic_timer_interrupt+0x12/0x20
[ 2203.656654] RIP: 0010:default_idle+0x13/0x20
[ 2203.656663] Code: 89 f0 5d 41 5c 41 5d 41 5e c3 cc cc cc cc cc cc cc
cc cc cc cc cc cc 0f 1f 44 00 00 0f 1f 44 00 00 0f 00 2d 9f 32 57 00 fb
f4 <c3> cc cc cc cc 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 54 be 08
[ 2203.656668] RSP: 0018:ffff88810036fe78 EFLAGS: 00000256
[ 2203.656676] RAX: ffffffffaf2a87f0 RBX: ffff888100360000 RCX:
ffffffffaf290191
[ 2203.656681] RDX: 0000000000098b5e RSI: 0000000000000004 RDI:
ffff88811a3c4f60
[ 2203.656686] RBP: 0000000000000000 R08: 0000000000000001 R09:
ffff88811a3c4f63
[ 2203.656690] R10: ffffed10234789ec R11: 0000000000000001 R12:
0000000000000003
[ 2203.656695] R13: ffff888100360000 R14: 0000000000000000 R15:
0000000000000000
[ 2203.656729] default_idle_call+0x5a/0x150
[ 2203.656735] cpuidle_idle_call+0x1c6/0x220
[ 2203.656780] do_idle+0xab/0x100
[ 2203.656786] cpu_startup_entry+0x19/0x20
[ 2203.656793] secondary_startup_64_no_verify+0xc2/0xcb

[ 2203.657409] The buggy address belongs to the page:
[ 2203.658648] page:0000000027a9842f refcount:1 mapcount:0
mapping:0000000000000000 index:0x0 pfn:0x11a388
[ 2203.658665] flags:
0x17ffffc0001000(reserved|node=0|zone=2|lastcpupid=0x1fffff)
[ 2203.658675] raw: 0017ffffc0001000 ffffea000468e208 ffffea000468e208
0000000000000000
[ 2203.658682] raw: 0000000000000000 0000000000000000 00000001ffffffff
0000000000000000
[ 2203.658686] page dumped because: kasan: bad access detected

To reproduce(ipvlan with IPVLAN_MODE_L3):
Env setting:
=======================================================
modprobe ipvlan ipvlan_default_mode=1
sysctl net.ipv4.conf.eth0.forwarding=1
iptables -t nat -A POSTROUTING -s 20.0.0.0/255.255.255.0 -o eth0 -j
MASQUERADE
ip link add gw link eth0 type ipvlan
ip -4 addr add 20.0.0.254/24 dev gw
ip netns add net1
ip link add ipv1 link eth0 type ipvlan
ip link set ipv1 netns net1
ip netns exec net1 ip link set ipv1 up
ip netns exec net1 ip -4 addr add 20.0.0.4/24 dev ipv1
ip netns exec net1 route add default gw 20.0.0.254
ip netns exec net1 tc qdisc add dev ipv1 root netem loss 10%
ifconfig gw up
iptables -t filter -A OUTPUT -p tcp --dport 8888 -j REJECT --reject-with
icmp-port-unreachable
=======================================================
And then excute the shell(curl any address of eth0 can reach):

for((i=1;i<=100000;i++))
do
ip netns exec net1 curl x.x.x.x:8888
done
=======================================================

Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.")
Signed-off-by: "t.feng" <fengtao40@huawei.com>
Suggested-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: use skb_ip_totlen in ipvlan_get_L3_hdr

ipvlan devices calls netif_inherit_tso_max() to get the tso_max_size/segs
from the lower device, so when lower device supports BIG TCP, the ipvlan
devices support it too. We also should consider its iph tot_len accessing.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipvlan: Fix out-of-bound bugs caused by unset skb->mac_header

If an AF_PACKET socket is used to send packets through ipvlan and the
default xmit function of the AF_PACKET socket is changed from
dev_queue_xmit() to packet_direct_xmit() via setsockopt() with the option
name of PACKET_QDISC_BYPASS, the skb->mac_header may not be reset and
remains as the initial value of 65535, this may trigger slab-out-of-bounds
bugs as following:

=================================================================
UG: KASAN: slab-out-of-bounds in ipvlan_xmit_mode_l2+0xdb/0x330 [ipvlan]
PU: 2 PID: 1768 Comm: raw_send Kdump: loaded Not tainted 6.0.0-rc4+ #6
ardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33
all Trace:
print_address_description.constprop.0+0x1d/0x160
print_report.cold+0x4f/0x112
kasan_report+0xa3/0x130
ipvlan_xmit_mode_l2+0xdb/0x330 [ipvlan]
ipvlan_start_xmit+0x29/0xa0 [ipvlan]
__dev_direct_xmit+0x2e2/0x380
packet_direct_xmit+0x22/0x60
packet_snd+0x7c9/0xc40
sock_sendmsg+0x9a/0xa0
__sys_sendto+0x18a/0x230
__x64_sys_sendto+0x74/0x90
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd

The root cause is:
1. packet_snd() only reset skb->mac_header when sock->type is SOCK_RAW
and skb->protocol is not specified as in packet_parse_headers()

2. packet_direct_xmit() doesn't reset skb->mac_header as dev_queue_xmit()

In this case, skb->mac_header is 65535 when ipvlan_xmit_mode_l2() is
called. So when ipvlan_xmit_mode_l2() gets mac header with eth_hdr() which
use "skb->head + skb->mac_header", out-of-bound access occurs.

This patch replaces eth_hdr() with skb_eth_hdr() in ipvlan_xmit_mode_l2()
and reset mac header in multicast to solve this out-of-bound bug.

Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.")
Signed-off-by: Lu Wei <luwei32@huawei.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: adopt u64_stats_t

As explained in commit 316580b69d0a ("u64_stats: provide u64_stats_t type")
we should use u64_stats_t and related accessors to avoid load/store tearing.

Add READ_ONCE() when reading rx_errs & tx_drps.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: add per-cpu storage and net->core_stats

Before adding yet another possibly contended atomic_long_t,
it is time to add per-cpu storage for existing ones:
dev->tx_dropped, dev->rx_dropped, and dev->rx_nohandler

Because many devices do not have to increment such counters,
allocate the per-cpu storage on demand, so that dev_get_stats()
does not have to spend considerable time folding zero counters.

Note that some drivers have abused these counters which
were supposed to be only used by core networking stack.

v4: should use per_cpu_ptr() in dev_get_stats() (Jakub)
v3: added a READ_ONCE() in netdev_core_stats_alloc() (Paolo)
v2: add a missing include (reported by kernel test robot <lkp@intel.com>)
Change in netdev_core_stats_alloc() (Jakub)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: jeffreyji <jeffreyji@google.com>
Reviewed-by: Brian Vazquez <brianvv@google.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20220311051420.2608812-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipvlan: Remove redundant if statements

The 'if (dev)' statement already move into dev_{put , hold}, so remove
redundant if statements.

Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: remove h from printk format specifier

This change fixes the checkpatch warning described in this commit
commit cbacb5ab0aa0 ("docs: printk-formats: Stop encouraging use of
unnecessary %h[xudi] and %hh[xudi]")

Standard integer promotion is already done and %hx and %hhx is useless
so do not encourage the use of %hh[xudi] or %h[xudi].

Cleanup output to use __func__ over explicit function strings.

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20210124190804.1964580-1-trix@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipvlan: do not use cond_resched_rcu() in ipvlan_process_multicast()

Commit e18b353f102e ("ipvlan: add cond_resched_rcu() while
processing muticast backlog") added a cond_resched_rcu() in a loop
using rcu protection to iterate over slaves.

This is breaking rcu rules, so lets instead use cond_resched()
at a point we can reschedule

Fixes: e18b353f102e ("ipvlan: add cond_resched_rcu() while processing muticast backlog")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: add cond_resched_rcu() while processing muticast backlog

If there are substantial number of slaves created as simulated by
Syzbot, the backlog processing could take much longer and result
into the issue found in the Syzbot report.

INFO: rcu_sched detected stalls on CPUs/tasks:
(detected by 1, t=10502 jiffies, g=5049, c=5048, q=752)
All QSes seen, last rcu_sched kthread activity 10502 (4294965563-4294955061), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor.1 R running task on cpu 1 10984 11210 3866 0x30020008 179034491270
Call Trace:
<IRQ>
[<ffffffff81497163>] _sched_show_task kernel/sched/core.c:8063 [inline]
[<ffffffff81497163>] _sched_show_task.cold+0x2fd/0x392 kernel/sched/core.c:8030
[<ffffffff8146a91b>] sched_show_task+0xb/0x10 kernel/sched/core.c:8073
[<ffffffff815c931b>] print_other_cpu_stall kernel/rcu/tree.c:1577 [inline]
[<ffffffff815c931b>] check_cpu_stall kernel/rcu/tree.c:1695 [inline]
[<ffffffff815c931b>] __rcu_pending kernel/rcu/tree.c:3478 [inline]
[<ffffffff815c931b>] rcu_pending kernel/rcu/tree.c:3540 [inline]
[<ffffffff815c931b>] rcu_check_callbacks.cold+0xbb4/0xc29 kernel/rcu/tree.c:2876
[<ffffffff815e3962>] update_process_times+0x32/0x80 kernel/time/timer.c:1635
[<ffffffff816164f0>] tick_sched_handle+0xa0/0x180 kernel/time/tick-sched.c:161
[<ffffffff81616ae4>] tick_sched_timer+0x44/0x130 kernel/time/tick-sched.c:1193
[<ffffffff815e75f7>] __run_hrtimer kernel/time/hrtimer.c:1393 [inline]
[<ffffffff815e75f7>] __hrtimer_run_queues+0x307/0xd90 kernel/time/hrtimer.c:1455
[<ffffffff815e90ea>] hrtimer_interrupt+0x2ea/0x730 kernel/time/hrtimer.c:1513
[<ffffffff844050f4>] local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1031 [inline]
[<ffffffff844050f4>] smp_apic_timer_interrupt+0x144/0x5e0 arch/x86/kernel/apic/apic.c:1056
[<ffffffff84401cbe>] apic_timer_interrupt+0x8e/0xa0 arch/x86/entry/entry_64.S:778
RIP: 0010:do_raw_read_lock+0x22/0x80 kernel/locking/spinlock_debug.c:153
RSP: 0018:ffff8801dad07ab8 EFLAGS: 00000a02 ORIG_RAX: ffffffffffffff12
RAX: 0000000000000000 RBX: ffff8801c4135680 RCX: 0000000000000000
RDX: 1ffff10038826afe RSI: ffff88019d816bb8 RDI: ffff8801c41357f0
RBP: ffff8801dad07ac0 R08: 0000000000004b15 R09: 0000000000310273
R10: ffff88019d816bb8 R11: 0000000000000001 R12: ffff8801c41357e8
R13: 0000000000000000 R14: ffff8801cfb19850 R15: ffff8801cfb198b0
[<ffffffff8101460e>] __raw_read_lock_bh include/linux/rwlock_api_smp.h:177 [inline]
[<ffffffff8101460e>] _raw_read_lock_bh+0x3e/0x50 kernel/locking/spinlock.c:240
[<ffffffff840d78ca>] ipv6_chk_mcast_addr+0x11a/0x6f0 net/ipv6/mcast.c:1006
[<ffffffff84023439>] ip6_mc_input+0x319/0x8e0 net/ipv6/ip6_input.c:482
[<ffffffff840211c8>] dst_input include/net/dst.h:449 [inline]
[<ffffffff840211c8>] ip6_rcv_finish+0x408/0x610 net/ipv6/ip6_input.c:78
[<ffffffff840214de>] NF_HOOK include/linux/netfilter.h:292 [inline]
[<ffffffff840214de>] NF_HOOK include/linux/netfilter.h:286 [inline]
[<ffffffff840214de>] ipv6_rcv+0x10e/0x420 net/ipv6/ip6_input.c:278
[<ffffffff83a29efa>] __netif_receive_skb_one_core+0x12a/0x1f0 net/core/dev.c:5303
[<ffffffff83a2a15c>] __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:5417
[<ffffffff83a2f536>] process_backlog+0x216/0x6c0 net/core/dev.c:6243
[<ffffffff83a30d1b>] napi_poll net/core/dev.c:6680 [inline]
[<ffffffff83a30d1b>] net_rx_action+0x47b/0xfb0 net/core/dev.c:6748
[<ffffffff846002c8>] __do_softirq+0x2c8/0x99a kernel/softirq.c:317
[<ffffffff813e656a>] invoke_softirq kernel/softirq.c:399 [inline]
[<ffffffff813e656a>] irq_exit+0x16a/0x1a0 kernel/softirq.c:439
[<ffffffff84405115>] exiting_irq arch/x86/include/asm/apic.h:561 [inline]
[<ffffffff84405115>] smp_apic_timer_interrupt+0x165/0x5e0 arch/x86/kernel/apic/apic.c:1058
[<ffffffff84401cbe>] apic_timer_interrupt+0x8e/0xa0 arch/x86/entry/entry_64.S:778
</IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:102
RSP: 0018:ffff880196033bd8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff12
RAX: ffff88019d8161c0 RBX: 00000000ffffffff RCX: ffffc90003501000
RDX: 0000000000000002 RSI: ffffffff816236d1 RDI: 0000000000000005
RBP: ffff880196033bd8 R08: ffff88019d8161c0 R09: 0000000000000000
R10: 1ffff10032c067f0 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000080 R14: 0000000000000000 R15: 0000000000000000
[<ffffffff816236d1>] do_futex+0x151/0x1d50 kernel/futex.c:3548
[<ffffffff816260f0>] C_SYSC_futex kernel/futex_compat.c:201 [inline]
[<ffffffff816260f0>] compat_SyS_futex+0x270/0x3b0 kernel/futex_compat.c:175
[<ffffffff8101da17>] do_syscall_32_irqs_on arch/x86/entry/common.c:353 [inline]
[<ffffffff8101da17>] do_fast_syscall_32+0x357/0xe1c arch/x86/entry/common.c:415
[<ffffffff84401a9b>] entry_SYSENTER_compat+0x8b/0x9d arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7f23c69
RSP: 002b:00000000f5d1f12c EFLAGS: 00000282 ORIG_RAX: 00000000000000f0
RAX: ffffffffffffffda RBX: 000000000816af88 RCX: 0000000000000080
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000816af8c
RBP: 00000000f5d1f228 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu_sched kthread starved for 10502 jiffies! g5049 c5048 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1
rcu_sched R running task on cpu 1 13048 8 2 0x90000000 179099587640
Call Trace:
[<ffffffff8147321f>] context_switch+0x60f/0xa60 kernel/sched/core.c:3209
[<ffffffff8100095a>] __schedule+0x5aa/0x1da0 kernel/sched/core.c:3934
[<ffffffff810021df>] schedule+0x8f/0x1b0 kernel/sched/core.c:4011
[<ffffffff8101116d>] schedule_timeout+0x50d/0xee0 kernel/time/timer.c:1803
[<ffffffff815c13f1>] rcu_gp_kthread+0xda1/0x3b50 kernel/rcu/tree.c:2327
[<ffffffff8144b318>] kthread+0x348/0x420 kernel/kthread.c:246
[<ffffffff84400266>] ret_from_fork+0x56/0x70 arch/x86/entry/entry_64.S:393

Fixes: ba35f8588f47 (“ipvlan: Defer multicast / broadcast processing to a work-queue”)
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: don't deref eth hdr before checking it's set

IPvlan in L3 mode discards outbound multicast packets but performs
the check before ensuring the ether-header is set or not. This is
an error that Eric found through code browsing.

Fixes: 2ad7bf363841 (“ipvlan: Initial check-in of the IPVLAN driver.”)
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ipvlan: decouple l3s mode dependencies from other modes

Right now ipvlan has a hard dependency on CONFIG_NETFILTER and
otherwise it cannot be built. However, the only ipvlan operation
mode that actually depends on netfilter is l3s, everything else
is independent of it. Break this hard dependency such that users
are able to use ipvlan l3 mode on systems where netfilter is not
compiled in.

Therefore, this adds a hidden CONFIG_IPVLAN_L3S bool which is
defaulting to y when CONFIG_NETFILTER is set in order to retain
existing behavior for l3s. All l3s related code is refactored
into ipvlan_l3s.c that is compiled in when enabled.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Mahesh Bandewar <maheshb@google.com>
Cc: Florian Westphal <fw@strlen.de>
Cc: Martynas Pumputis <m@lambda.lt>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6: Pass skb to route lookup

IPv6 does path selection for multipath routes deep in the lookup
functions. The next patch adds L4 hash option and needs the skb
for the forward path. To get the skb to the relevant FIB lookup
functions it needs to go through the fib rules layer, so add a
lookup_data argument to the fib_lookup_arg struct.

Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: use per device spinlock to protect addrs list updates

This changeset moves ipvlan address under RCU protection, using
a per ipvlan device spinlock to protect list mutation and RCU
read access to protect list traversal.

Also explicitly use RCU read lock to traverse the per port
ipvlans list, so that we can now perform a full address lookup
without asserting the RTNL lock.

Overall this allows the ipvlan driver to check fully for duplicate
addresses - before this commit ipv6 addresses assigned by autoconf
via prefix delegation where accepted without any check - and avoid
the following rntl assertion failure still in the same code path:

RTNL: assertion failed at drivers/net/ipvlan/ipvlan_core.c (124)
WARNING: CPU: 15 PID: 0 at drivers/net/ipvlan/ipvlan_core.c:124 ipvlan_addr_busy+0x97/0xa0 [ipvlan]
Modules linked in: ipvlan(E) ixgbe
CPU: 15 PID: 0 Comm: swapper/15 Tainted: G E 4.16.0-rc2.ipvlan+ #1782
Hardware name: Dell Inc. PowerEdge R730/072T6D, BIOS 2.1.7 06/16/2016
RIP: 0010:ipvlan_addr_busy+0x97/0xa0 [ipvlan]
RSP: 0018:ffff881ff9e03768 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff881fdf2a9000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 00000000000000f6 RDI: 0000000000000300
RBP: ffff881fdf2a8000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: ffff881ff9e034c0 R12: ffff881fe07bcc00
R13: 0000000000000001 R14: ffffffffa02002b0 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff881ff9e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc5c1a4f248 CR3: 000000207e012005 CR4: 00000000001606e0
Call Trace:
<IRQ>
ipvlan_addr6_event+0x6c/0xd0 [ipvlan]
notifier_call_chain+0x49/0x90
atomic_notifier_call_chain+0x6a/0x100
ipv6_add_addr+0x5f9/0x720
addrconf_prefix_rcv_add_addr+0x244/0x3c0
addrconf_prefix_rcv+0x2f3/0x790
ndisc_router_discovery+0x633/0xb70
ndisc_rcv+0x155/0x180
icmpv6_rcv+0x4ac/0x5f0
ip6_input_finish+0x138/0x6a0
ip6_input+0x41/0x1f0
ipv6_rcv+0x4db/0x8d0
__netif_receive_skb_core+0x3d5/0xe40
netif_receive_skb_internal+0x89/0x370
napi_gro_receive+0x14f/0x1e0
ixgbe_clean_rx_irq+0x4ce/0x1020 [ixgbe]
ixgbe_poll+0x31a/0x7a0 [ixgbe]
net_rx_action+0x296/0x4f0
__do_softirq+0xcf/0x4f5
irq_exit+0xf5/0x110
do_IRQ+0x62/0x110
common_interrupt+0x91/0x91
</IRQ>

v1 -> v2: drop unneeded in_softirq check in ipvlan_addr6_validator_event()

Fixes: e9997c2938b2 ("ipvlan: fix check for IP addresses in control path")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: egress mcast packets are not exceptional

Currently, if IPv6 is enabled on top of an ipvlan device in l3
mode, the following warning message:

Dropped {multi|broad}cast of type= [86dd]

is emitted every time that a RS is generated and dmseg is soon
filled with irrelevant messages. Replace pr_warn with pr_debug,
to preserve debuggability, without scaring the sysadmin.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: drop ipv6 dependency

IPVlan has an hard dependency on IPv6, refactor the ipvlan code to allow
compiling it with IPv6 disabled, move duplicate code into addr_equal()
and refactor series of if-else into a switch.

Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: remove excessive packet scrubbing

IPvlan currently scrubs packets at every location where packets may be
crossing namespace boundary. Though this is desirable, currently IPvlan
does it more than necessary. e.g. packets that are going to take
dev_forward_skb() path will get scrubbed so no point in scrubbing them
before forwarding. Another side-effect of scrubbing is that pkt-type gets
set to PACKET_HOST which overrides what was already been set by the
earlier path making erroneous delivery of the packets.

Also scrubbing packets just before calling dev_queue_xmit() has detrimental
effects since packets lose skb->sk and because of that miss prio updates,
incorrect socket back-pressure and would even break TSQ.

Fixes: b93dd49c1a35 ('ipvlan: Scrub skb before crossing the namespace boundary')
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Revert "ipvlan: add L2 check for packets arriving via virtual devices"

This reverts commit 92ff42645028fa6f9b8aa767718457b9264316b4.

Even though the check added is not that taxing, it's not really needed.
First of all this will be per packet cost and second thing is that the
eth_type_trans() already does this correctly. The excessive scrubbing
in IPvlan was changing the pkt-type skb metadata of the packet which
made it necessary to re-check the mac. The subsequent patch in this
series removes the faulty packet-scrub.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: add L2 check for packets arriving via virtual devices

Packets that don't have dest mac as the mac of the master device should
not be entertained by the IPvlan rx-handler. This is mostly true as the
packet path mostly takes care of that, except when the master device is
a virtual device. As demonstrated in the following case -

ip netns add ns1
ip link add ve1 type veth peer name ve2
ip link add link ve2 name iv1 type ipvlan mode l2
ip link set dev iv1 netns ns1
ip link set ve1 up
ip link set ve2 up
ip -n ns1 link set iv1 up
ip addr add 192.168.10.1/24 dev ve1
ip -n ns1 addr 192.168.10.2/24 dev iv1
ping -c2 192.168.10.2
<Works!>
ip neigh show dev ve1
ip neigh show 192.168.10.2 lladdr <random> dev ve1
ping -c2 192.168.10.2
<Still works! Wrong!!>

This patch adds that missing check in the IPvlan rx-handler.

Reported-by: Amit Sikka <amit.sikka@ericsson.com>
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: Eliminate duplicated codes with existing function

The recv flow of ipvlan l2 mode performs as same as l3 mode for
non-multicast packet, so use the existing func ipvlan_handle_mode_l3
instead of these duplicated statements in non-multicast case.

Signed-off-by: Gao Feng <gfree.wind@vip.163.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: Add the skb->mark as flow4's member to lookup route

Current codes don't use skb->mark to assign flowi4_mark, it would
make the policy route rule with fwmark doesn't work as expected.

Signed-off-by: Gao Feng <gfree.wind@vip.163.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: Fix insufficient skb linear check for ipv6 icmp

In the function ipvlan_get_L3_hdr, current codes use pskb_may_pull to
make sure the skb header has enough linear room for ipv6 header. But it
would use the latter memory directly without linear check when it is icmp.
So it still may access the unepxected memory in ipvlan_addr_lookup.

Now invoke the pskb_may_pull again if it is ipv6 icmp.

Signed-off-by: Gao Feng <gfree.wind@vip.163.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: Fix insufficient skb linear check for arp

In the function ipvlan_get_L3_hdr, current codes use pskb_may_pull to
make sure the skb header has enough linear room for arp header. But it
would access the arp payload in func ipvlan_addr_lookup. So it still may
access the unepxected memory.

Now use arp_hdr_len(port->dev) instead of the arp header as the param.

Signed-off-by: Gao Feng <gfree.wind@vip.163.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: fix ipv6 outbound device

When process the outbound packet of ipv6, we should assign the master
device to output device other than input device.

Signed-off-by: Keefe Liu <liuqifa@huawei.com>
Acked-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: implement VEPA mode

This is very similar to the Macvlan VEPA mode, however, there is some
difference. IPvlan uses the mac-address of the lower device, so the VEPA
mode has implications of ICMP-redirects for packets destined for its
immediate neighbors sharing same master since the packets will have same
source and dest mac. The external switch/router will send redirect msg.

Having said that, this will be useful tool in terms of debugging
since IPvlan will not switch packets within its slaves and rely completely
on the external entity as intended in 802.1Qbg.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: introduce 'private' attribute for all existing modes.

IPvlan has always operated in bridge mode. However there are scenarios
where each slave should be able to talk through the master device but
not necessarily across each other. Think of an environment where each
of a namespace is a private and independant customer. In this scenario
the machine which is hosting these namespaces neither want to tell who
their neighbor is nor the individual namespaces care to talk to neighbor
on short-circuited network path.

This patch implements the mode that is very similar to the 'private' mode
in macvlan where individual slaves can send and receive traffic through
the master device, just that they can not talk among slave devices.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvtap: IP-VLAN based tap driver

This patch adds a tap character device driver that is based on the
IP-VLAN network interface, called ipvtap. An ipvtap device can be created
in the same way as an ipvlan device, using 'type ipvtap', and then accessed
using the tap user space interface.

Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

driver: ipvlan: Remove unnecessary ipvlan NULL check in ipvlan_count_rx

There are three functions which would invoke the ipvlan_count_rx. They
are ipvlan_process_multicast, ipvlan_rcv_frame, and ipvlan_nf_input.
The former two functions already use the ipvlan directly before
ipvlan_count_rx, and ipvlan_nf_input gets the ipvlan from
ipvl_addr->master, it is not possible to be NULL too.
So the ipvlan pointer check is unnecessary in ipvlan_count_rx.

Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: fix multicast processing

In an IPvlan setup when master is set in loopback mode e.g.

ethtool -K eth0 set loopback on

where eth0 is master device for IPvlan setup.

The failure is caused by the faulty logic that determines if the
packet is from TX-path vs. RX-path by just looking at the mac-
addresses on the packet while processing multicast packets.

In the loopback-mode where this crash was happening, the packets
that are sent out are reflected by the NIC and are processed on
the RX path, but mac-address check tricks into thinking this
packet is from TX path and falsely uses dev_forward_skb() to pass
packets to the slave (virtual) devices.

This patch records the path while queueing packets and eliminates
logic of looking at mac-addresses for the same decision.

------------[ cut here ]------------
kernel BUG at include/linux/skbuff.h:1737!
Call Trace:
[<ffffffff921fbbc2>] dev_forward_skb+0x92/0xd0
[<ffffffffc031ac65>] ipvlan_process_multicast+0x395/0x4c0 [ipvlan]
[<ffffffffc031a9a7>] ? ipvlan_process_multicast+0xd7/0x4c0 [ipvlan]
[<ffffffff91cdfea7>] ? process_one_work+0x147/0x660
[<ffffffff91cdff09>] process_one_work+0x1a9/0x660
[<ffffffff91cdfea7>] ? process_one_work+0x147/0x660
[<ffffffff91ce086d>] worker_thread+0x11d/0x360
[<ffffffff91ce0750>] ? rescuer_thread+0x350/0x350
[<ffffffff91ce960b>] kthread+0xdb/0xe0
[<ffffffff91c05c70>] ? _raw_spin_unlock_irq+0x30/0x50
[<ffffffff91ce9530>] ? flush_kthread_worker+0xc0/0xc0
[<ffffffff92348b7a>] ret_from_fork+0x9a/0xd0
[<ffffffff91ce9530>] ? flush_kthread_worker+0xc0/0xc0

Fixes: ba35f8588f47 ("ipvlan: Defer multicast / broadcast processing to a work-queue")
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
CC: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: fix various issues in ipvlan_process_multicast()

1) netif_rx() / dev_forward_skb() should not be called from process
context.

2) ipvlan_count_rx() should be called with preemption disabled.

3) We should check if ipvlan->dev is up before feeding packets
to netif_rx()

4) We need to prevent device from disappearing if some packets
are in the multicast backlog.

5) One kfree_skb() should be a consume_skb() eventually

Fixes: ba35f8588f47 ("ipvlan: Defer multicast / broadcast processing to
a work-queue")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: Introduce l3s mode

In a typical IPvlan L3 setup where master is in default-ns and
each slave is into different (slave) ns. In this setup egress
packet processing for traffic originating from slave-ns will
hit all NF_HOOKs in slave-ns as well as default-ns. However same
is not true for ingress processing. All these NF_HOOKs are
hit only in the slave-ns skipping them in the default-ns.
IPvlan in L3 mode is restrictive and if admins want to deploy
iptables rules in default-ns, this asymmetric data path makes it
impossible to do so.

This patch makes use of the l3_rcv() (added as part of l3mdev
enhancements) to perform input route lookup on RX packets without
changing the skb->dev and then uses nf_hook at NF_INET_LOCAL_IN
to change the skb->dev just before handing over skb to L4.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
CC: David Ahern <dsa@cumulusnetworks.com>
Reviewed-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: Scrub skb before crossing the namespace boundry

The earlier patch c3aaa06d5a63 (ipvlan: scrub skb before routing
in L3 mode.) did this but only for TX path in L3 mode. This
patch extends it for both the modes for TX/RX path.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: misc changes

1. scope correction for few functions that are used in single file.
2. Adjust variables that are used in fast-path to fit into single cacheline
3. Update rcv_frame() to skip shared check for frames coming over wire

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: scrub skb before routing in L3 mode.

Scrub skb before hitting the iptable hooks to ensure packets hit
these hooks. Set the xnet param only when the packet is crossing the
ns boundry so if the IPvlan slave and master belong to the same ns,
the param will be set to false.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
CC: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: fix use after free of skb

ipvlan_handle_frame is a rx_handler, and when it returns a value other
than RX_HANDLER_CONSUMED (here, NET_RX_DROP aka RX_HANDLER_ANOTHER),
__netif_receive_skb_core expects that the skb still exists and will
process it further, but we just freed it.

Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: fix leak in ipvlan_rcv_frame

Pass a **skb to ipvlan_rcv_frame so that if skb_share_check returns a
new skb, we actually use it during further processing.

It's safe to ignore the new skb in the ipvlan_xmit_* functions, because
they call ipvlan_rcv_frame with local == true, so that dev_forward_skb
is called and always takes ownership of the skb.

Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: read direct ifindex instead of iflink

In the ipv4 outbound path of an ipvlan device in l3 mode, the ifindex is
being grabbed from dev_get_iflink. This works for the physical device
case, since as the documentation of that function notes: "Physical
interfaces have the same 'ifindex' and 'iflink' values.". However, if
the master device is a veth, and the pairs are in separate net
namespaces, the route lookup will fail with -ENODEV due to outer veth
pair being in a separate namespace from the ipvlan master/routing
namespace.

ns0 | ns1 | ns2
veth0a--|--veth0b--|--ipvl0

In ipvlan_process_v4_outbound(), a packet sent from ipvl0 in the above
configuration will pass fl.flowi4_oif == veth0a to
ip_route_output_flow(), but *net == ns1.

Notice also that ipv6 processing is not using iflink. Since there is a
discrepancy in usage, fixup both v4 and v6 case to use local dev
variable.

Tested this with l3 ipvlan on top of veth, as well as with single
physical interface in the top namespace.

Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>
Reviewed-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4, ipv6: Pass net into ip_local_out and ip6_local_out

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: Cache net in ipvlan_process_v4_outbound and ipvlan_process_v6_outbound

Compute net once in ipvlan_process_v4_outbound and
ipvlan_process_v6_outbound and store it in a variable so that net does
not need to be recomputed next time it is used.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6: Merge ip6_local_out and ip6_local_out_sk

Stop hidding the sk parameter with an inline helper function and make
all of the callers pass it, so that it is clear what the function is
doing.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: Merge ip_local_out and ip_local_out_sk

It is confusing and silly hiding a parameter so modify all of
the callers to pass in the appropriate socket or skb->sk if
no socket is known.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: use rcu_deference_bh() in ipvlan_queue_xmit()

In tx path rcu_read_lock_bh() is held, so we need rcu_deference_bh().
This fixes the following warning:

===============================
[ INFO: suspicious RCU usage. ]
4.1.0-rc1+ #1007 Not tainted
-------------------------------
drivers/net/ipvlan/ipvlan.h:106 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 0
1 lock held by dhclient/1076:
#0: (rcu_read_lock_bh){......}, at: [<ffffffff817e8d84>] rcu_lock_acquire+0x0/0x26

stack backtrace:
CPU: 2 PID: 1076 Comm: dhclient Not tainted 4.1.0-rc1+ #1007
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
0000000000000001 ffff8800d381bac8 ffffffff81a4154f 000000003c1a3c19
ffff8800d4d0a690 ffff8800d381baf8 ffffffff810b849f ffff880117d41148
ffff880117d40000 ffff880117d40068 0000000000000156 ffff8800d381bb18
Call Trace:
[<ffffffff81a4154f>] dump_stack+0x4c/0x65
[<ffffffff810b849f>] lockdep_rcu_suspicious+0x107/0x110
[<ffffffff8165a522>] ipvlan_port_get_rcu+0x47/0x4e
[<ffffffff8165ad14>] ipvlan_queue_xmit+0x35/0x450
[<ffffffff817ea45d>] ? rcu_read_unlock+0x3e/0x5f
[<ffffffff810a20bf>] ? local_clock+0x19/0x22
[<ffffffff810b4781>] ? __lock_is_held+0x39/0x52
[<ffffffff8165b64c>] ipvlan_start_xmit+0x1b/0x44
[<ffffffff817edf7f>] dev_hard_start_xmit+0x2ae/0x467
[<ffffffff817ee642>] __dev_queue_xmit+0x50a/0x60c
[<ffffffff817ee7a7>] dev_queue_xmit_sk+0x13/0x15
[<ffffffff81997596>] dev_queue_xmit+0x10/0x12
[<ffffffff8199b41c>] packet_sendmsg+0xb6b/0xbdf
[<ffffffff810b5ea7>] ? mark_lock+0x2e/0x226
[<ffffffff810a1fcc>] ? sched_clock_cpu+0x9e/0xb7
[<ffffffff817d56f9>] sock_sendmsg_nosec+0x12/0x1d
[<ffffffff817d7257>] sock_sendmsg+0x29/0x2e
[<ffffffff817d72cc>] sock_write_iter+0x70/0x91
[<ffffffff81199563>] __vfs_write+0x7e/0xa7
[<ffffffff811996bc>] vfs_write+0x92/0xe8
[<ffffffff811997d7>] SyS_write+0x47/0x7e
[<ffffffff81a4d517>] system_call_fastpath+0x12/0x6f

Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.")
Cc: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Mahesh Bandewar <maheshb@google.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: unhash addresses without synchronize_rcu

All structures used in traffic forwarding are rcu-protected:
ipvl_addr, ipvl_dev and ipvl_port. Thus we can unhash addresses
without synchronization. We'll anyway hash it back into the same
bucket: in worst case lockless lookup will scan hash once again.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: Defer multicast / broadcast processing to a work-queue

Processing multicast / broadcast in fast path is performance draining
and having more links means more cloning and bringing performance
down further.

Broadcast; in particular, need to be given to all the virtual links.
Earlier tricks of enabling broadcast bit for IPv4 only interfaces are not
really working since it fails autoconf. Which means enabling broadcast
for all the links if protocol specific hacks do not have to be added into
the driver.

This patch defers all (incoming as well as outgoing) multicast traffic to
a work-queue leaving only the unicast traffic in the fast-path. Now if we
need to apply any additional tricks to further reduce the impact of this
(multicast / broadcast) type of traffic, it can be implemented while
processing this work without affecting the fast-path.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

dev: introduce dev_get_iflink()

The goal of this patch is to prepare the removal of the iflink field. It
introduces a new ndo function, which will be implemented by virtual interfaces.

There is no functional change into this patch. All readers of iflink field
now call dev_get_iflink().

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

ipvlan: fix check for IP addresses in control path

When an ipvlan interface is down, its addresses are not on the hash list.
Fix checks for existence of addresses not to depend on the hash list, walk
through all interface addresses instead.

Signed-off-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: protect against concurrent link removal

Adding and removing to the 'ipvlans' list is already done using _rcu list
operations.

Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: fix addr hash list corruption

When ipvlan interface with IP addresses attached is brought down and then
deleted, the assigned addresses are deleted twice from the address hash
list, first on the interface down and second on the link deletion.
Similarly, when an address is added while the interface is down, it is added
second time once the interface is brought up.

When the interface is down, the addresses should be kept off the hash list
for performance reasons. Ensure this is true, which also fixes the double add
problem. To fix the double free, check whether the address is hashed before
removing it.

Reported-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mark some potential candidates __read_mostly

They are all either written once or extremly rarely (e.g. from init
code), so we can move them to the .data..read_mostly section.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: fix incorrect usage of IS_ERR() macro in IPv6 code path.

The ip6_route_output() always returns a valid dst pointer unlike in IPv4
case. So the validation has to be different from the IPv4 path. Correcting
that error in this patch.

This was picked up by a static checker with a following warning -

drivers/net/ipvlan/ipvlan_core.c:380 ipvlan_process_v6_outbound()
warn: 'dst' isn't an ERR_PTR

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipvlan: Initial check-in of the IPVLAN driver.

This driver is very similar to the macvlan driver except that it
uses L3 on the frame to determine the logical interface while
functioning as packet dispatcher. It inherits L2 of the master
device hence the packets on wire will have the same L2 for all
the packets originating from all virtual devices off of the same
master device.

This driver was developed keeping the namespace use-case in
mind. Hence most of the examples given here take that as the
base setup where main-device belongs to the default-ns and
virtual devices are assigned to the additional namespaces.

The device operates in two different modes and the difference
in these two modes in primarily in the TX side.

(a) L2 mode : In this mode, the device behaves as a L2 device.
TX processing upto L2 happens on the stack of the virtual device
associated with (namespace). Packets are switched after that
into the main device (default-ns) and queued for xmit.

RX processing is simple and all multicast, broadcast (if
applicable), and unicast belonging to the address(es) are
delivered to the virtual devices.

(b) L3 mode : In this mode, the device behaves like a L3 device.
TX processing upto L3 happens on the stack of the virtual device
associated with (namespace). Packets are switched to the
main-device (default-ns) for the L2 processing. Hence the routing
table of the default-ns will be used in this mode.

RX processins is somewhat similar to the L2 mode except that in
this mode only Unicast packets are delivered to the virtual device
while main-dev will handle all other packets.

The devices can be added using the "ip" command from the iproute2
package -

ip link add link <master> <virtual> type ipvlan mode [ l2 | l3 ]

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Laurent Chavey <chavey@google.com>
Cc: Tim Hockin <thockin@google.com>
Cc: Brandon Philips <brandon.philips@coreos.com>
Cc: Pavel Emelianov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>