linux/drivers/net/vxlan, branch v6.17

vxlan: Fix NPD in {arp,neigh}_reduce() when using nexthop objects

2025-09-02T23:57:00Z

When the "proxy" option is enabled on a VXLAN device, the device will suppress ARP requests and IPv6 Neighbor Solicitation messages if it is able to reply on behalf of the remote host. That is, if a matching and valid neighbor entry is configured on the VXLAN device whose MAC address is not behind the "any" remote (0.0.0.0 / ::). The code currently assumes that the FDB entry for the neighbor's MAC address points to a valid remote destination, but this is incorrect if the entry is associated with an FDB nexthop group. This can result in a NPD [1][3] which can be reproduced using [2][4]. Fix by checking that the remote destination exists before dereferencing it. [1] BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] CPU: 4 UID: 0 PID: 365 Comm: arping Not tainted 6.17.0-rc2-virtme-g2a89cb21162c #2 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014 RIP: 0010:vxlan_xmit+0xb58/0x15f0 [...] Call Trace: dev_hard_start_xmit+0x5d/0x1c0 __dev_queue_xmit+0x246/0xfd0 packet_sendmsg+0x113a/0x1850 __sock_sendmsg+0x38/0x70 __sys_sendto+0x126/0x180 __x64_sys_sendto+0x24/0x30 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x4b/0x53 [2] #!/bin/bash ip address add 192.0.2.1/32 dev lo ip nexthop add id 1 via 192.0.2.2 fdb ip nexthop add id 10 group 1 fdb ip link add name vx0 up type vxlan id 10010 local 192.0.2.1 dstport 4789 proxy ip neigh add 192.0.2.3 lladdr 00:11:22:33:44:55 nud perm dev vx0 bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10 arping -b -c 1 -s 192.0.2.1 -I vx0 192.0.2.3 [3] BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] CPU: 13 UID: 0 PID: 372 Comm: ndisc6 Not tainted 6.17.0-rc2-virtmne-g6ee90cb26014 #3 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1v996), BIOS 1.17.0-4.fc41 04/01/2x014 RIP: 0010:vxlan_xmit+0x803/0x1600 [...] Call Trace: dev_hard_start_xmit+0x5d/0x1c0 __dev_queue_xmit+0x246/0xfd0 ip6_finish_output2+0x210/0x6c0 ip6_finish_output+0x1af/0x2b0 ip6_mr_output+0x92/0x3e0 ip6_send_skb+0x30/0x90 rawv6_sendmsg+0xe6e/0x12e0 __sock_sendmsg+0x38/0x70 __sys_sendto+0x126/0x180 __x64_sys_sendto+0x24/0x30 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7f383422ec77 [4] #!/bin/bash ip address add 2001:db8:1::1/128 dev lo ip nexthop add id 1 via 2001:db8:1::1 fdb ip nexthop add id 10 group 1 fdb ip link add name vx0 up type vxlan id 10010 local 2001:db8:1::1 dstport 4789 proxy ip neigh add 2001:db8:1::3 lladdr 00:11:22:33:44:55 nud perm dev vx0 bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10 ndisc6 -r 1 -s 2001:db8:1::1 -w 1 2001:db8:1::3 vx0 Fixes: 1274e1cc4226 ("vxlan: ecmp support for mac fdb entries") Reviewed-by: Petr Machata Signed-off-by: Ido Schimmel Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20250901065035.159644-3-idosch@nvidia.com Signed-off-by: Jakub Kicinski

vxlan: Fix NPD when refreshing an FDB entry with a nexthop object

2025-09-02T23:56:59Z

VXLAN FDB entries can point to either a remote destination or an FDB nexthop group. The latter is usually used in EVPN deployments where learning is disabled. However, when learning is enabled, an incoming packet might try to refresh an FDB entry that points to an FDB nexthop group and therefore does not have a remote. Such packets should be dropped, but they are only dropped after dereferencing the non-existent remote, resulting in a NPD [1] which can be reproduced using [2]. Fix by dropping such packets earlier. Remove the misleading comment from first_remote_rcu(). [1] BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] CPU: 13 UID: 0 PID: 361 Comm: mausezahn Not tainted 6.17.0-rc1-virtme-g9f6b606b6b37 #1 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014 RIP: 0010:vxlan_snoop+0x98/0x1e0 [...] Call Trace: vxlan_encap_bypass+0x209/0x240 encap_bypass_if_local+0xb1/0x100 vxlan_xmit_one+0x1375/0x17e0 vxlan_xmit+0x6b4/0x15f0 dev_hard_start_xmit+0x5d/0x1c0 __dev_queue_xmit+0x246/0xfd0 packet_sendmsg+0x113a/0x1850 __sock_sendmsg+0x38/0x70 __sys_sendto+0x126/0x180 __x64_sys_sendto+0x24/0x30 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x4b/0x53 [2] #!/bin/bash ip address add 192.0.2.1/32 dev lo ip address add 192.0.2.2/32 dev lo ip nexthop add id 1 via 192.0.2.3 fdb ip nexthop add id 10 group 1 fdb ip link add name vx0 up type vxlan id 10010 local 192.0.2.1 dstport 12345 localbypass ip link add name vx1 up type vxlan id 10020 local 192.0.2.2 dstport 54321 learning bridge fdb add 00:11:22:33:44:55 dev vx0 self static dst 192.0.2.2 port 54321 vni 10020 bridge fdb add 00:aa:bb:cc:dd:ee dev vx1 self static nhid 10 mausezahn vx0 -a 00:aa:bb:cc:dd:ee -b 00:11:22:33:44:55 -c 1 -q Fixes: 1274e1cc4226 ("vxlan: ecmp support for mac fdb entries") Reported-by: Marlin Cremers Reviewed-by: Petr Machata Signed-off-by: Ido Schimmel Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20250901065035.159644-2-idosch@nvidia.com Signed-off-by: Jakub Kicinski

vxlan: remove redundant conversion of vni in vxlan_nl2conf

2025-07-24T00:09:29Z

The IFLA_VXLAN_ID data has been converted to local variable vni in vxlan_nl2conf(), there is no need to do it again when set conf->vni. Signed-off-by: Wang Liang Acked-by: Nikolay Aleksandrov Reviewed-by: Petr Machata Link: https://patch.msgid.link/20250722093049.1527505-1-wangliang74@huawei.com Signed-off-by: Jakub Kicinski

netlink: introduce type-checking attribute iteration for nlmsg

2025-07-02T22:39:04Z

Add the nlmsg_for_each_attr_type() macro to simplify iteration over attributes of a specific type in a Netlink message. Convert existing users in vxlan and nfsd to use the new macro. Suggested-by: Jakub Kicinski Signed-off-by: Carolina Jubran Signed-off-by: Mark Bloch Link: https://patch.msgid.link/20250629142138.361537-2-mbloch@nvidia.com Signed-off-by: Jakub Kicinski

vxlan: drop sock_lock

2025-06-19T01:53:51Z

We won't be able to sleep soon in vxlan_offload_rx_ports and won't be able to grab sock_lock. Instead of having separate spinlock to manage sockets, rely on rtnl lock. This is similar to how geneve manages its sockets. Signed-off-by: Stanislav Fomichev Reviewed-by: Ido Schimmel Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20250616162117.287806-3-stfomichev@gmail.com Signed-off-by: Jakub Kicinski

vxlan: Support MC routing in the underlay

2025-06-18T01:18:46Z

Locally-generated MC packets have so far not been subject to MC routing. Instead an MC-enabled installation would maintain the MC routing tables, and separately from that the list of interfaces to send packets to as part of the VXLAN FDB and MDB. In a previous patch, a ip_mr_output() and ip6_mr_output() routines were added for IPv4 and IPv6. All locally generated MC traffic is now passed through these functions. For reasons of backward compatibility, an SKB (IPCB / IP6CB) flag guards the actual MC routing. This patch adds logic to set the flag, and the UAPI to enable the behavior. Signed-off-by: Petr Machata Reviewed-by: Ido Schimmel Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/d899655bb7e9b2521ee8c793e67056b9fd02ba12.1750113335.git.petrm@nvidia.com Signed-off-by: Jakub Kicinski

net: ipv6: Add a flags argument to ip6tunnel_xmit(), udp_tunnel6_xmit_skb()

2025-06-18T01:18:45Z

ip6tunnel_xmit() erases the contents of the SKB control block. In order to be able to set particular IP6CB flags on the SKB, add a corresponding parameter, and propagate it to udp_tunnel6_xmit_skb() as well. In one of the following patches, VXLAN driver will use this facility to mark packets as subject to IPv6 multicast routing. Signed-off-by: Petr Machata Reviewed-by: Ido Schimmel Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/acb4f9f3e40c3a931236c3af08a720b017fbfbfb.1750113335.git.petrm@nvidia.com Signed-off-by: Jakub Kicinski

net: ipv4: Add a flags argument to iptunnel_xmit(), udp_tunnel_xmit_skb()

2025-06-18T01:18:44Z

iptunnel_xmit() erases the contents of the SKB control block. In order to be able to set particular IPCB flags on the SKB, add a corresponding parameter, and propagate it to udp_tunnel_xmit_skb() as well. In one of the following patches, VXLAN driver will use this facility to mark packets as subject to IP multicast routing. Signed-off-by: Petr Machata Reviewed-by: Ido Schimmel Reviewed-by: Nikolay Aleksandrov Acked-by: Antonio Quartulli Link: https://patch.msgid.link/89c9daf9f2dc088b6b92ccebcc929f51742de91f.1750113335.git.petrm@nvidia.com Signed-off-by: Jakub Kicinski

treewide, timers: Rename from_timer() to timer_container_of()

2025-06-08T07:07:37Z

Move this API to the canonical timer_*() namespace. [ tglx: Redone against pre rc1 ] Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2025-04-24T18:20:52Z

Cross-merge networking fixes after downstream PR (net-6.15-rc4). This pull includes wireless and a fix to vxlan which isn't in Linus's tree just yet. The latter creates with a silent conflict / build breakage, so merging it now to avoid causing problems. drivers/net/vxlan/vxlan_vnifilter.c 094adad91310 ("vxlan: Use a single lock to protect the FDB table") 087a9eb9e597 ("vxlan: vnifilter: Fix unlocked deletion of default FDB entry") https://lore.kernel.org/20250423145131.513029-1-idosch@nvidia.com No "normal" conflicts, or adjacent changes. Signed-off-by: Jakub Kicinski