netfilter: Pass struct net into the netfilter hooks
authorEric W. Biederman <ebiederm@xmission.com>
Wed, 16 Sep 2015 01:04:16 +0000 (20:04 -0500)
committerDavid S. Miller <davem@davemloft.net>
Fri, 18 Sep 2015 00:18:37 +0000 (17:18 -0700)
commit29a26a56803855a79dbd028cd61abee56237d6e5
tree89fb3a95216d44417577e218a967ede09d676922
parent04eb44890e5bb3cc855e5c0f18a05eb7311364b7
netfilter: Pass struct net into the netfilter hooks

Pass a network namespace parameter into the netfilter hooks.  At the
call site of the netfilter hooks the path a packet is taking through
the network stack is well known which allows the network namespace to
be easily and reliabily.

This allows the replacement of magic code like
"dev_net(state->in?:state->out)" that appears at the start of most
netfilter hooks with "state->net".

In almost all cases the network namespace passed in is derived
from the first network device passed in, guaranteeing those
paths will not see any changes in practice.

The exceptions are:
xfrm/xfrm_output.c:xfrm_output_resume()         xs_net(skb_dst(skb)->xfrm)
ipvs/ip_vs_xmit.c:ip_vs_nat_send_or_cont()      ip_vs_conn_net(cp)
ipvs/ip_vs_xmit.c:ip_vs_send_or_cont()          ip_vs_conn_net(cp)
ipv4/raw.c:raw_send_hdrinc()                    sock_net(sk)
ipv6/ip6_output.c:ip6_xmit() sock_net(sk)
ipv6/ndisc.c:ndisc_send_skb()                   dev_net(skb->dev) not dev_net(dst->dev)
ipv6/raw.c:raw6_send_hdrinc()                   sock_net(sk)
br_netfilter_hooks.c:br_nf_pre_routing_finish() dev_net(skb->dev) before skb->dev is set to nf_bridge->physindev

In all cases these exceptions seem to be a better expression for the
network namespace the packet is being processed in then the historic
"dev_net(in?in:out)".  I am documenting them in case something odd
pops up and someone starts trying to track down what happened.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
31 files changed:
drivers/net/vrf.c
include/linux/netfilter.h
net/bridge/br_forward.c
net/bridge/br_input.c
net/bridge/br_multicast.c
net/bridge/br_netfilter_hooks.c
net/bridge/br_netfilter_ipv6.c
net/bridge/br_stp_bpdu.c
net/decnet/dn_neigh.c
net/decnet/dn_nsp_in.c
net/decnet/dn_route.c
net/ipv4/arp.c
net/ipv4/ip_forward.c
net/ipv4/ip_input.c
net/ipv4/ip_output.c
net/ipv4/ipmr.c
net/ipv4/raw.c
net/ipv4/xfrm4_input.c
net/ipv4/xfrm4_output.c
net/ipv6/ip6_input.c
net/ipv6/ip6_output.c
net/ipv6/ip6mr.c
net/ipv6/mcast.c
net/ipv6/ndisc.c
net/ipv6/netfilter/nf_defrag_ipv6_hooks.c
net/ipv6/output_core.c
net/ipv6/raw.c
net/ipv6/xfrm6_input.c
net/ipv6/xfrm6_output.c
net/netfilter/ipvs/ip_vs_xmit.c
net/xfrm/xfrm_output.c