kernel/linux.git/net/ipv4/netfilter.c, branch v6.6.131

netfilter: Use l3mdev flow key when re-routing mangled packets

2022-05-16T11:03:29+00:00

Commit 40867d74c374 ("net: Add l3mdev index to flow struct and avoid oif reset for port devices") introduces a flow key specific for layer 3 domains, such as a VRF master device. This allows for explicit VRF domain selection instead of abusing the oif flow key. Update ip[6]_route_me_harder() to make use of that new key when re-routing mangled packets within VRFs instead of setting the flow oif, making it consistent with other users. Signed-off-by: Martin Willi Reviewed-by: David Ahern Signed-off-by: Pablo Neira Ayuso

netfilter: Dissect flow after packet mangling

2021-04-18T20:04:16+00:00

Netfilter tries to reroute mangled packets as a different route might need to be used following the mangling. When this happens, netfilter does not populate the IP protocol, the source port and the destination port in the flow key. Therefore, FIB rules that match on these fields are ignored and packets can be misrouted. Solve this by dissecting the outer flow and populating the flow key before rerouting the packet. Note that flow dissection only happens when FIB rules that match on these fields are installed, so in the common case there should not be a penalty. Reported-by: Michal Soltys Signed-off-by: Ido Schimmel Signed-off-by: Pablo Neira Ayuso

netfilter: use actual socket sk rather than skb sk when routing harder

2020-10-30T11:57:39+00:00

If netfilter changes the packet mark when mangling, the packet is rerouted using the route_me_harder set of functions. Prior to this commit, there's one big difference between route_me_harder and the ordinary initial routing functions, described in the comment above __ip_queue_xmit(): /* Note: skb->sk can be different from sk, in case of tunnels */ int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl, That function goes on to correctly make use of sk->sk_bound_dev_if, rather than skb->sk->sk_bound_dev_if. And indeed the comment is true: a tunnel will receive a packet in ndo_start_xmit with an initial skb->sk. It will make some transformations to that packet, and then it will send the encapsulated packet out of a *new* socket. That new socket will basically always have a different sk_bound_dev_if (otherwise there'd be a routing loop). So for the purposes of routing the encapsulated packet, the routing information as it pertains to the socket should come from that socket's sk, rather than the packet's original skb->sk. For that reason __ip_queue_xmit() and related functions all do the right thing. One might argue that all tunnels should just call skb_orphan(skb) before transmitting the encapsulated packet into the new socket. But tunnels do *not* do this -- and this is wisely avoided in skb_scrub_packet() too -- because features like TSQ rely on skb->destructor() being called when that buffer space is truely available again. Calling skb_orphan(skb) too early would result in buffers filling up unnecessarily and accounting info being all wrong. Instead, additional routing must take into account the new sk, just as __ip_queue_xmit() notes. So, this commit addresses the problem by fishing the correct sk out of state->sk -- it's already set properly in the call to nf_hook() in __ip_local_out(), which receives the sk as part of its normal functionality. So we make sure to plumb state->sk through the various route_me_harder functions, and then make correct use of it following the example of __ip_queue_xmit(). Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Jason A. Donenfeld Reviewed-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso

netfilter: ipv4: remove useless export_symbol

2019-01-28T10:32:58+00:00

Only one caller; place it where needed and get rid of the EXPORT_SYMBOL. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso

netfilter: utils: move nf_ip_checksum* from ipv4 to utils

2018-07-16T15:51:48+00:00

allows to make nf_ip_checksum_partial static, it no longer has an external caller. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso

netfilter: remove struct nf_afinfo and its helper functions

2018-01-08T17:11:02+00:00

This abstraction has no clients anymore, remove it. This is what remains from previous authors, so correct copyright statement after recent modifications and code removal. Signed-off-by: Pablo Neira Ayuso

netfilter: remove route_key_size field in struct nf_afinfo

2018-01-08T17:11:01+00:00

This is only needed by nf_queue, place this code where it belongs. Signed-off-by: Pablo Neira Ayuso

netfilter: move reroute indirection to struct nf_ipv6_ops

2018-01-08T17:10:53+00:00

We cannot make a direct call to nf_ip6_reroute() because that would result in autoloading the 'ipv6' module because of symbol dependencies. Therefore, define reroute indirection in nf_ipv6_ops where this really belongs to. For IPv4, we can indeed make a direct function call, which is faster, given IPv4 is built-in in the networking code by default. Still, CONFIG_INET=n and CONFIG_NETFILTER=y is possible, so define empty inline stub for IPv4 in such case. Signed-off-by: Pablo Neira Ayuso

netfilter: move route indirection to struct nf_ipv6_ops

2018-01-08T17:01:26+00:00

We cannot make a direct call to nf_ip6_route() because that would result in autoloading the 'ipv6' module because of symbol dependencies. Therefore, define route indirection in nf_ipv6_ops where this really belongs to. For IPv4, we can indeed make a direct function call, which is faster, given IPv4 is built-in in the networking code by default. Still, CONFIG_INET=n and CONFIG_NETFILTER=y is possible, so define empty inline stub for IPv4 in such case. Signed-off-by: Pablo Neira Ayuso

netfilter: remove saveroute indirection in struct nf_afinfo

2018-01-08T17:01:25+00:00

This is only used by nf_queue.c and this function comes with no symbol dependencies with IPv6, it just refers to structure layouts. Therefore, we can replace it by a direct function call from where it belongs. Signed-off-by: Pablo Neira Ayuso