kernel/linux.git/include/net/fib_rules.h, branch v6.19.11

net: fib_rules: Fix iif / oif matching on L3 master device

2025-04-16T00:54:56+00:00

Before commit 40867d74c374 ("net: Add l3mdev index to flow struct and avoid oif reset for port devices") it was possible to use FIB rules to match on a L3 domain. This was done by having a FIB rule match on iif / oif being a L3 master device. It worked because prior to the FIB rule lookup the iif / oif fields in the flow structure were reset to the index of the L3 master device to which the input / output device was enslaved to. The above scheme made it impossible to match on the original input / output device. Therefore, cited commit stopped overwriting the iif / oif fields in the flow structure and instead stored the index of the enslaving L3 master device in a new field ('flowi_l3mdev') in the flow structure. While the change enabled new use cases, it broke the original use case of matching on a L3 domain. Fix this by interpreting the iif / oif matching on a L3 master device as a match against the L3 domain. In other words, if the iif / oif in the FIB rule points to a L3 master device, compare the provided index against 'flowi_l3mdev' rather than 'flowi_{i,o}if'. Before cited commit, a FIB rule that matched on 'iif vrf1' would only match incoming traffic from devices enslaved to 'vrf1'. With the proposed change (i.e., comparing against 'flowi_l3mdev'), the rule would also match traffic originating from a socket bound to 'vrf1'. Avoid that by adding a new flow flag ('FLOWI_FLAG_L3MDEV_OIF') that indicates if the L3 domain was derived from the output interface or the input interface (when not set) and take this flag into account when evaluating the FIB rule against the flow structure. Avoid unnecessary checks in the data path by detecting that a rule matches on a L3 master device when the rule is installed and marking it as such. Tested using the following script [1]. Output before 40867d74c374 (v5.4.291): default dev dummy1 table 100 scope link default dev dummy1 table 200 scope link Output after 40867d74c374: default dev dummy1 table 300 scope link default dev dummy1 table 300 scope link Output with this patch: default dev dummy1 table 100 scope link default dev dummy1 table 200 scope link [1] #!/bin/bash ip link add name vrf1 up type vrf table 10 ip link add name dummy1 up master vrf1 type dummy sysctl -wq net.ipv4.conf.all.forwarding=1 sysctl -wq net.ipv4.conf.all.rp_filter=0 ip route add table 100 default dev dummy1 ip route add table 200 default dev dummy1 ip route add table 300 default dev dummy1 ip rule add prio 0 oif vrf1 table 100 ip rule add prio 1 iif vrf1 table 200 ip rule add prio 2 table 300 ip route get 192.0.2.1 oif dummy1 fibmatch ip route get 192.0.2.1 iif dummy1 from 198.51.100.1 fibmatch Fixes: 40867d74c374 ("net: Add l3mdev index to flow struct and avoid oif reset for port devices") Reported-by: hanhuihui Closes: https://lore.kernel.org/netdev/ec671c4f821a4d63904d0da15d604b75@huawei.com/ Signed-off-by: Ido Schimmel Acked-by: David Ahern Link: https://patch.msgid.link/20250414172022.242991-2-idosch@nvidia.com Signed-off-by: Jakub Kicinski

ipv4: fib_rules: Add port mask matching

2025-02-20T02:43:38+00:00

Extend IPv4 FIB rules to match on source and destination ports using a mask. Note that the mask is only set when not matching on a range. Reviewed-by: Petr Machata Signed-off-by: Ido Schimmel Reviewed-by: Guillaume Nault Reviewed-by: David Ahern Link: https://patch.msgid.link/20250217134109.311176-4-idosch@nvidia.com Signed-off-by: Jakub Kicinski

net: fib_rules: Add port mask support

2025-02-20T02:43:38+00:00

Add support for configuring and deleting rules that match on source and destination ports using a mask as well as support for dumping such rules to user space. Reviewed-by: Petr Machata Signed-off-by: Ido Schimmel Reviewed-by: Guillaume Nault Reviewed-by: David Ahern Link: https://patch.msgid.link/20250217134109.311176-3-idosch@nvidia.com Signed-off-by: Jakub Kicinski

net: fib_rules: Factorise fib_newrule() and fib_delrule().

2025-02-11T03:08:52+00:00

fib_nl_newrule() / fib_nl_delrule() is the doit() handler for RTM_NEWRULE / RTM_DELRULE but also called from vrf_newlink(). Currently, we hold RTNL on both paths but will not on the former. Also, we set dev_net(dev)->rtnl to skb->sk in vrf_fib_rule() because fib_nl_newrule() / fib_nl_delrule() fetch net as sock_net(skb->sk). Let's Factorise the two functions and pass net and rtnl_held flag. Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Reviewed-by: Ido Schimmel Tested-by: Ido Schimmel Link: https://patch.msgid.link/20250207072502.87775-6-kuniyu@amazon.com Signed-off-by: Jakub Kicinski

fib: rules: use READ_ONCE()/WRITE_ONCE() on ops->fib_rules_seq

2024-10-11T22:35:05+00:00

Using RTNL to protect ops->fib_rules_seq reads seems a big hammer. Writes are protected by RTNL. We can use READ_ONCE() on readers. Constify 'struct net' argument of fib_rules_seq_read() and lookup_rules_ops(). Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Reviewed-by: David Ahern Link: https://patch.msgid.link/20241009184405.3752829-2-edumazet@google.com Signed-off-by: Jakub Kicinski

fib: remove unnecessary input parameters in fib_default_rule_add

2024-01-04T00:42:48+00:00

When fib_default_rule_add is invoked, the value of the input parameter 'flags' is always 0. Rules uses kzalloc to allocate memory, so 'flags' has been initialized to 0. Therefore, remove the input parameter 'flags' in fib_default_rule_add. Signed-off-by: Zhengchao Shao Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240102071519.3781384-1-shaozhengchao@huawei.com Signed-off-by: Jakub Kicinski

fib: expand fib_rule_policy

2021-12-16T15:18:35+00:00

Now that there is only one fib nla_policy there is no need to keep the macro around. Place it where its used. Signed-off-by: Florian Westphal Reviewed-by: David Ahern Signed-off-by: Jakub Kicinski

fib: rules: remove duplicated nla policies

2021-12-16T15:18:35+00:00

The attributes are identical in all implementations so move the ipv4 one into the core and remove the per-family nla policies. Signed-off-by: Florian Westphal Reviewed-by: David Ahern Signed-off-by: Jakub Kicinski

ipv6: fix memory leak in fib6_rule_suppress

2021-11-29T14:43:35+00:00

The kernel leaks memory when a `fib` rule is present in IPv6 nftables firewall rules and a suppress_prefix rule is present in the IPv6 routing rules (used by certain tools such as wg-quick). In such scenarios, every incoming packet will leak an allocation in `ip6_dst_cache` slab cache. After some hours of `bpftrace`-ing and source code reading, I tracked down the issue to ca7a03c41753 ("ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule"). The problem with that change is that the generic `args->flags` always have `FIB_LOOKUP_NOREF` set[1][2] but the IPv6-specific flag `RT6_LOOKUP_F_DST_NOREF` might not be, leading to `fib6_rule_suppress` not decreasing the refcount when needed. How to reproduce: - Add the following nftables rule to a prerouting chain: meta nfproto ipv6 fib saddr . mark . iif oif missing drop This can be done with: sudo nft create table inet test sudo nft create chain inet test test_chain '{ type filter hook prerouting priority filter + 10; policy accept; }' sudo nft add rule inet test test_chain meta nfproto ipv6 fib saddr . mark . iif oif missing drop - Run: sudo ip -6 rule add table main suppress_prefixlength 0 - Watch `sudo slabtop -o | grep ip6_dst_cache` to see memory usage increase with every incoming ipv6 packet. This patch exposes the protocol-specific flags to the protocol specific `suppress` function, and check the protocol-specific `flags` argument for RT6_LOOKUP_F_DST_NOREF instead of the generic FIB_LOOKUP_NOREF when decreasing the refcount, like this. [1]: https://github.com/torvalds/linux/blob/ca7a03c4175366a92cee0ccc4fec0038c3266e26/net/ipv6/fib6_rules.c#L71 [2]: https://github.com/torvalds/linux/blob/ca7a03c4175366a92cee0ccc4fec0038c3266e26/net/ipv6/fib6_rules.c#L99 Link: https://bugzilla.kernel.org/show_bug.cgi?id=215105 Fixes: ca7a03c41753 ("ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule") Cc: stable@vger.kernel.org Signed-off-by: Jason A. Donenfeld Signed-off-by: David S. Miller

fib: use indirect call wrappers in the most common fib_rules_ops

2020-07-29T00:42:31+00:00

This avoids another inderect call per RX packet which save us around 20-40 ns. Changelog: v1 -> v2: - Move declaraions to fib_rules.h to remove warnings Reported-by: kernel test robot Signed-off-by: Brian Vazquez Signed-off-by: David S. Miller