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| author | Martin Willi <martin@strongswan.org> | 2021-04-19 16:15:59 +0200 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2021-04-22 23:18:02 +0200 |
| commit | 22b6034323fd736f260e00b9ea85c634abeb3446 (patch) | |
| tree | ffde46e4c1596f6588240f869ec84d2335b6039d /net/core | |
| parent | d044d9fc1380b66917dcb418ef4ec7e59dd6e597 (diff) | |
| download | linux-22b6034323fd736f260e00b9ea85c634abeb3446.tar.gz linux-22b6034323fd736f260e00b9ea85c634abeb3446.tar.bz2 linux-22b6034323fd736f260e00b9ea85c634abeb3446.zip | |
net, xdp: Update pkt_type if generic XDP changes unicast MAC
If a generic XDP program changes the destination MAC address from/to
multicast/broadcast, the skb->pkt_type is updated to properly handle
the packet when passed up the stack. When changing the MAC from/to
the NICs MAC, PACKET_HOST/OTHERHOST is not updated, though, making
the behavior different from that of native XDP.
Remember the PACKET_HOST/OTHERHOST state before calling the program
in generic XDP, and update pkt_type accordingly if the destination
MAC address has changed. As eth_type_trans() assumes a default
pkt_type of PACKET_HOST, restore that before calling it.
The use case for this is when a XDP program wants to push received
packets up the stack by rewriting the MAC to the NICs MAC, for
example by cluster nodes sharing MAC addresses.
Fixes: 297249569932 ("net: fix generic XDP to handle if eth header was mangled")
Signed-off-by: Martin Willi <martin@strongswan.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210419141559.8611-1-martin@strongswan.org
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/dev.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index b4c67a5be606..6a1ef7a15bed 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4723,10 +4723,10 @@ static u32 netif_receive_generic_xdp(struct sk_buff *skb, void *orig_data, *orig_data_end, *hard_start; struct netdev_rx_queue *rxqueue; u32 metalen, act = XDP_DROP; + bool orig_bcast, orig_host; u32 mac_len, frame_sz; __be16 orig_eth_type; struct ethhdr *eth; - bool orig_bcast; int off; /* Reinjected packets coming from act_mirred or similar should @@ -4773,6 +4773,7 @@ static u32 netif_receive_generic_xdp(struct sk_buff *skb, orig_data_end = xdp->data_end; orig_data = xdp->data; eth = (struct ethhdr *)xdp->data; + orig_host = ether_addr_equal_64bits(eth->h_dest, skb->dev->dev_addr); orig_bcast = is_multicast_ether_addr_64bits(eth->h_dest); orig_eth_type = eth->h_proto; @@ -4800,8 +4801,11 @@ static u32 netif_receive_generic_xdp(struct sk_buff *skb, /* check if XDP changed eth hdr such SKB needs update */ eth = (struct ethhdr *)xdp->data; if ((orig_eth_type != eth->h_proto) || + (orig_host != ether_addr_equal_64bits(eth->h_dest, + skb->dev->dev_addr)) || (orig_bcast != is_multicast_ether_addr_64bits(eth->h_dest))) { __skb_push(skb, ETH_HLEN); + skb->pkt_type = PACKET_HOST; skb->protocol = eth_type_trans(skb, skb->dev); } |