linux/net/bridge
Ido Schimmel 29cfb2aaa4 bridge: Add backup nexthop ID support
Add a new bridge port attribute that allows attaching a nexthop object
ID to an skb that is redirected to a backup bridge port with VLAN
tunneling enabled.

Specifically, when redirecting a known unicast packet, read the backup
nexthop ID from the bridge port that lost its carrier and set it in the
bridge control block of the skb before forwarding it via the backup
port. Note that reading the ID from the bridge port should not result in
a cache miss as the ID is added next to the 'backup_port' field that was
already accessed. After this change, the 'state' field still stays on
the first cache line, together with other data path related fields such
as 'flags and 'vlgrp':

struct net_bridge_port {
        struct net_bridge *        br;                   /*     0     8 */
        struct net_device *        dev;                  /*     8     8 */
        netdevice_tracker          dev_tracker;          /*    16     0 */
        struct list_head           list;                 /*    16    16 */
        long unsigned int          flags;                /*    32     8 */
        struct net_bridge_vlan_group * vlgrp;            /*    40     8 */
        struct net_bridge_port *   backup_port;          /*    48     8 */
        u32                        backup_nhid;          /*    56     4 */
        u8                         priority;             /*    60     1 */
        u8                         state;                /*    61     1 */
        u16                        port_no;              /*    62     2 */
        /* --- cacheline 1 boundary (64 bytes) --- */
[...]
} __attribute__((__aligned__(8)));

When forwarding an skb via a bridge port that has VLAN tunneling
enabled, check if the backup nexthop ID stored in the bridge control
block is valid (i.e., not zero). If so, instead of attaching the
pre-allocated metadata (that only has the tunnel key set), allocate a
new metadata, set both the tunnel key and the nexthop object ID and
attach it to the skb.

By default, do not dump the new attribute to user space as a value of
zero is an invalid nexthop object ID.

The above is useful for EVPN multihoming. When one of the links
composing an Ethernet Segment (ES) fails, traffic needs to be redirected
towards the host via one of the other ES peers. For example, if a host
is multihomed to three different VTEPs, the backup port of each ES link
needs to be set to the VXLAN device and the backup nexthop ID needs to
point to an FDB nexthop group that includes the IP addresses of the
other two VTEPs. The VXLAN driver will extract the ID from the metadata
of the redirected skb, calculate its flow hash and forward it towards
one of the other VTEPs. If the ID does not exist, or represents an
invalid nexthop object, the VXLAN driver will drop the skb. This
relieves the bridge driver from the need to validate the ID.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-07-19 10:53:49 +01:00
..
netfilter netfilter: bridge: introduce broute meta statement 2023-03-08 14:21:18 +01:00
br_arp_nd_proxy.c bridge: Add per-{Port, VLAN} neighbor suppression data path support 2023-04-21 08:25:50 +01:00
br_cfm_netlink.c bridge: cfm: Netlink Notifications. 2020-10-29 18:39:44 -07:00
br_cfm.c bridge: cfm: remove redundant return 2021-06-22 10:35:15 -07:00
br_device.c skbuff: bridge: Add layer 2 miss indication 2023-05-30 23:37:00 -07:00
br_fdb.c bridge: switchdev: Allow device drivers to install locked FDB entries 2022-11-09 19:06:13 -08:00
br_forward.c bridge: Add backup nexthop ID support 2023-07-19 10:53:49 +01:00
br_if.c net: bridge: keep ports without IFF_UNICAST_FLT in BR_PROMISC mode 2023-07-03 09:11:34 +01:00
br_input.c skbuff: bridge: Add layer 2 miss indication 2023-05-30 23:37:00 -07:00
br_ioctl.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2021-12-31 14:35:40 +00:00
br_mdb.c rtnetlink: bridge: mcast: Relax group address validation in common code 2023-03-17 08:05:49 +00:00
br_mrp_netlink.c bridge: mrp: Use hlist_head instead of list_head for mrp 2020-11-09 16:42:12 -08:00
br_mrp_switchdev.c bridge: mrp: Extend br_mrp_switchdev to detect better the errors 2021-02-16 14:47:46 -08:00
br_mrp.c net: bridge: mrp: Update the Test frames for MRA 2021-06-28 15:46:10 -07:00
br_mst.c net: bridge: mst: Add helper to query a port's MST state 2022-03-17 16:49:58 -07:00
br_multicast_eht.c treewide: Convert del_timer*() to timer_shutdown*() 2022-12-25 13:38:09 -08:00
br_multicast.c net: bridge: Add netlink knobs for number / maximum MDB entries 2023-02-06 08:48:26 +00:00
br_netfilter_hooks.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-04-20 16:29:51 -07:00
br_netfilter_ipv6.c netfilter: move br_nf_check_hbh_len to utils 2023-03-08 14:25:40 +01:00
br_netlink_tunnel.c net: bridge: Set strict_start_type at two policies 2023-02-06 08:48:25 +00:00
br_netlink.c bridge: Add backup nexthop ID support 2023-07-19 10:53:49 +01:00
br_nf_core.c net: dst: Switch to rcuref_t reference counting 2023-03-28 18:52:28 -07:00
br_private_cfm.h bridge: cfm: Kernel space implementation of CFM. CCM frame RX added. 2020-10-29 18:39:43 -07:00
br_private_mcast_eht.h net: bridge: multicast: use multicast contexts instead of bridge or port 2021-07-20 05:41:19 -07:00
br_private_mrp.h net: bridge: mrp: Update the Test frames for MRA 2021-06-28 15:46:10 -07:00
br_private_stp.h
br_private_tunnel.h bridge: always declare tunnel functions 2023-05-17 21:28:58 -07:00
br_private.h bridge: Add backup nexthop ID support 2023-07-19 10:53:49 +01:00
br_stp_bpdu.c net: bridge: add STP xstats 2019-12-14 20:02:36 -08:00
br_stp_if.c net: use eth_hw_addr_set() 2021-10-02 14:18:25 +01:00
br_stp_timer.c
br_stp.c net: bridge: mst: Multiple Spanning Tree (MST) mode 2022-03-17 16:49:57 -07:00
br_switchdev.c net: bridge: switchdev: don't notify FDB entries with "master dynamic" 2023-04-20 09:20:14 +02:00
br_sysfs_br.c bridge: Fix flushing of dynamic FDB entries 2022-11-02 20:47:09 -07:00
br_sysfs_if.c bridge: move from strlcpy with unused retval to strscpy 2022-08-22 17:57:30 -07:00
br_vlan_options.c bridge: vlan: Allow setting VLAN neighbor suppression state 2023-04-21 08:25:50 +01:00
br_vlan_tunnel.c bridge: Add backup nexthop ID support 2023-07-19 10:53:49 +01:00
br_vlan.c bridge: vlan: Allow setting VLAN neighbor suppression state 2023-04-21 08:25:50 +01:00
br.c bridge: switchdev: Allow device drivers to install locked FDB entries 2022-11-09 19:06:13 -08:00
Kconfig bridge: cfm: Add BRIDGE_CFM to Kconfig. 2020-10-29 18:39:43 -07:00
Makefile net: bridge: mst: Multiple Spanning Tree (MST) mode 2022-03-17 16:49:57 -07:00