On Thu, Jun 06, 2024 at 11:47:33AM +0200, Daniel Borkmann wrote:

[ Upstream commit 1cd4bc987abb2823836cbb8f887026011ccddc8a ]

Commit f58f45c1e5b9 ("vxlan: drop packets from invalid src-address") has recently been added to vxlan mainly in the context of source address snooping/learning so that when it is enabled, an entry in the FDB is not being created for an invalid address for the corresponding tunnel endpoint.

Before commit f58f45c1e5b9 vxlan was similarly behaving as geneve in that it passed through whichever macs were set in the L2 header. It turns out that this change in behavior breaks setups, for example, Cilium with netkit in L3 mode for Pods as well as tunnel mode has been passing before the change in f58f45c1e5b9 for both vxlan and geneve. After mentioned change it is only passing for geneve as in case of vxlan packets are dropped due to vxlan_set_mac() returning false as source and destination macs are zero which for E/W traffic via tunnel is totally fine.

Fix it by only opting into the is_valid_ether_addr() check in vxlan_set_mac() when in fact source address snooping/learning is actually enabled in vxlan. This is done by moving the check into vxlan_snoop(). With this change, the Cilium connectivity test suite passes again for both tunnel flavors.

Fixes: f58f45c1e5b9 ("vxlan: drop packets from invalid src-address") Signed-off-by: Daniel Borkmann daniel@iogearbox.net Cc: David Bauer mail@david-bauer.net Cc: Ido Schimmel idosch@nvidia.com Cc: Nikolay Aleksandrov razor@blackwall.org Cc: Martin KaFai Lau martin.lau@kernel.org Reviewed-by: Ido Schimmel idosch@nvidia.com Reviewed-by: Nikolay Aleksandrov razor@blackwall.org Reviewed-by: David Bauer mail@david-bauer.net Signed-off-by: David S. Miller davem@davemloft.net [ Backport note: vxlan snooping/learning not supported in 6.8 or older, so commit is simply a revert. ] Signed-off-by: Daniel Borkmann daniel@iogearbox.net

---

drivers/net/vxlan/vxlan_core.c | 4 ---- 1 file changed, 4 deletions(-)

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c index 0a0b4a9717ce..1d0688610189 100644 --- a/drivers/net/vxlan/vxlan_core.c +++ b/drivers/net/vxlan/vxlan_core.c @@ -1615,10 +1615,6 @@ static bool vxlan_set_mac(struct vxlan_dev *vxlan, if (ether_addr_equal(eth_hdr(skb)->h_source, vxlan->dev->dev_addr)) return false;

• /* Ignore packets from invalid src-address */
• if (!is_valid_ether_addr(eth_hdr(skb)->h_source))

• return false;
  

• /* Get address from the outer IP header */ if (vxlan_get_sk_family(vs) == AF_INET) { saddr.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;

-- 2.34.1

All now queued up, thanks.

greg k-h