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BPF_FIB_LOOKUP_VLAN resolves a VLAN egress. The reverse is also useful: an XDP program receiving a VLAN-tagged frame on a physical device wants the lookup to behave as if the packet had arrived on the corresponding VLAN subinterface, so iif-based policy routing and VRF table selection use the right ingress. Add BPF_FIB_LOOKUP_VLAN_INPUT. When set, params->h_vlan_proto and params->h_vlan_TCI are read as an input VLAN tag and the matching VLAN device of params->ifindex is resolved with __vlan_find_dev_deep_rcu(). The device must be up and in the same network namespace as params->ifindex (a VLAN device can be moved to another netns while registered on its parent; receive would deliver into that other namespace, which a lookup here cannot represent). If params->ifindex is itself a VLAN device, its inner (QinQ) subinterface is matched. For a bond or team, a tag on a port matches no device and returns NOT_FWDED; pass the master's ifindex. The lookup then runs with the resolved device as the ingress; params->ifindex itself is not modified on the input side. When the resolved device is enslaved to a VRF, both the full lookup (via the l3mdev rule) and BPF_FIB_LOOKUP_DIRECT (via l3mdev_fib_table_rcu()) select the VRF's table from the resolved ingress. That follows from feeding the resolved device to the flow as the ingress (fl4.flowi4_iif = dev->ifindex), which is what makes l3mdev resolve the VRF master from the subinterface rather than from params->ifindex. The two failure classes get different treatment on purpose. A h_vlan_proto other than 802.1Q/802.1ad is API misuse and returns -EINVAL, since it would otherwise reach the WARN in vlan_proto_idx() with a program-controlled value. An unmatched VID, a device that is down, or one in another namespace is a data outcome and returns BPF_FIB_LKUP_RET_NOT_FWDED, matching the DIRECT path when fib_get_table() finds no table and mirroring real ingress, where the receive path drops such frames. A VID of 0 (a priority tag) is looked up literally and normally fails the same way; receive instead processes such frames untagged, so callers should not set the flag for priority tags. Proceeding on the physical device for any of these would be fail-open for the policy-routing cases above. The h_vlan fields share a union with tbid, so the flag cannot be combined with BPF_FIB_LOOKUP_TBID. It describes ingress, so it also cannot be combined with BPF_FIB_LOOKUP_OUTPUT. Both combinations return -EINVAL; restricting now keeps a later relaxation backward compatible. Combining with BPF_FIB_LOOKUP_VLAN is allowed: the tag is consumed on the ingress side and the egress tag is written on success. Under !CONFIG_VLAN_8021Q the __vlan_find_dev_deep_rcu() stub returns NULL, so every lookup with a valid proto returns NOT_FWDED, which is correct since no VLAN device can exist. Suggested-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Avinash Duduskar <avinash.duduskar@gmail.com> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com> Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com> Link: https://lore.kernel.org/bpf/20260713162305.1237211-3-avinash.duduskar@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> |
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| 6lowpan | ||
| 9p | ||
| 802 | ||
| 8021q | ||
| atm | ||
| batman-adv | ||
| bluetooth | ||
| bpf | ||
| bridge | ||
| can | ||
| ceph | ||
| core | ||
| dcb | ||
| devlink | ||
| dns_resolver | ||
| dsa | ||
| ethernet | ||
| ethtool | ||
| handshake | ||
| hsr | ||
| ieee802154 | ||
| ife | ||
| ipv4 | ||
| ipv6 | ||
| iucv | ||
| kcm | ||
| key | ||
| l2tp | ||
| l3mdev | ||
| lapb | ||
| llc | ||
| mac80211 | ||
| mac802154 | ||
| mctp | ||
| mpls | ||
| mptcp | ||
| ncsi | ||
| netfilter | ||
| netlabel | ||
| netlink | ||
| nfc | ||
| nsh | ||
| openvswitch | ||
| packet | ||
| phonet | ||
| psample | ||
| psp | ||
| qrtr | ||
| rds | ||
| rfkill | ||
| rxrpc | ||
| sched | ||
| sctp | ||
| shaper | ||
| smc | ||
| strparser | ||
| sunrpc | ||
| switchdev | ||
| tipc | ||
| tls | ||
| unix | ||
| vmw_vsock | ||
| wireless | ||
| x25 | ||
| xdp | ||
| xfrm | ||
| compat.c | ||
| devres.c | ||
| Kconfig | ||
| Kconfig.debug | ||
| Makefile | ||
| socket.c | ||
| sysctl_net.c | ||