netfilter: propagate net to nf_bridge_get_physindev

This is a preparation patch for replacing physindev with physinif on
nf_bridge_info structure. We will use dev_get_by_index_rcu to resolve
device, when needed, and it requires net to be available.

Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: use skb_ip_totlen and iph_totlen

There are also quite some places in netfilter that may process IPv4 TCP
GSO packets, we need to replace them too.

In length_mt(), we have to use u_int32_t/int to accept skb_ip_totlen()
return value, otherwise it may overflow and mismatch. This change will
also help us add selftest for IPv4 BIG TCP in the following patch.

Note that we don't need to replace the one in tcpmss_tg4(), as it will
return if there is data after tcphdr in tcpmss_mangle_packet(). The
same in mangle_contents() in nf_nat_helper.c, it returns false when
skb->len + extra > 65535 in enlarge_skb().

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

netfilter: nf_log: incorrect offset to network header

NFPROTO_ARP is expecting to find the ARP header at the network offset.

In the particular case of ARP, HTYPE= field shows the initial bytes of
the ethernet header destination MAC address.

netdev out: IN= OUT=bridge0 MACSRC=c2:76:e5:71:e1:de MACDST=36:b0:4a:e2:72:ea MACPROTO=0806 ARP HTYPE=14000 PTYPE=0x4ae2 OPCODE=49782

NFPROTO_NETDEV egress hook is also expecting to find the IP headers at
the network offset.

Fixes: 35b9395104d5 ("netfilter: add generic ARP packet logger")
Reported-by: Tom Yan <tom.ty89@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_log_syslog: Consolidate entry checks

Every syslog logging callback has to perform the same check to cover for
rogue containers, introduce a helper for clarity. Drop the FIXME as
there is a viable solution since commit 2851940ffee31 ("netfilter: allow
logging from non-init namespaces").

Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_log_syslog: Don't ignore unknown protocols

With netdev and bridge nfprotos, loggers may see arbitrary ethernet
frames. Print at least basic info like interfaces and MAC header data.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_log_syslog: Merge MAC header dumpers

The functions for IPv4 and IPv6 were almost identical apart from extra
SIT tunnel device handling in the latter.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_log_syslog: Unset bridge logger in pernet exit

Without this, a stale pointer remains in pernet loggers after module
unload causing a kernel oops during dereference. Easily reproduced by:

| # modprobe nf_log_syslog
| # rmmod nf_log_syslog
| # cat /proc/net/netfilter/nf_log

Fixes: 77ccee96a6742 ("netfilter: nf_log_bridge: merge with nf_log_syslog")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_log_common: merge with nf_log_syslog

Remove nf_log_common. Now that all per-af modules have been merged
there is no longer a need to provide a helper module.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_log_bridge: merge with nf_log_syslog

Provide bridge log support from nf_log_syslog.

After the merge there is no need to load the "real packet loggers",
all of them now reside in the same module.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_log_netdev: merge with nf_log_syslog

Provide netdev family support from the nf_log_syslog module.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_log_ipv6: merge with nf_log_syslog

This removes the nf_log_ipv6 module, the functionality is now
provided by nf_log_syslog.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_log_arp: merge with nf_log_syslog

similar to previous change: nf_log_syslog now covers ARP logging
as well, the old nf_log_arp module is removed.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_log_ipv4: rename to nf_log_syslog

Netfilter has multiple log modules:
nf_log_arp
nf_log_bridge
nf_log_ipv4
nf_log_ipv6
nf_log_netdev
nfnetlink_log
nf_log_common

With the exception of nfnetlink_log (packet is sent to userspace for
dissection/logging), all of them log to the kernel ringbuffer.

This is the first part of a series to merge all modules except
nfnetlink_log into a single module: nf_log_syslog.

This allows to reduce code. After the series, only two log modules remain:
nfnetlink_log and nf_log_syslog. The latter provides the same
functionality as the old per-af log modules.

This renames nf_log_ipv4 to nf_log_syslog.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>