diff options
| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2018-04-14 05:27:19 +0200 |
|---|---|---|
| committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2018-04-15 15:45:13 +0200 |
| commit | 0b12a85f27e9a41f8fd10536ebd23768f0d97519 (patch) | |
| tree | bb981631edcee904820cc64c3b4e584799176f62 /src/device.c | |
| parent | b11f5f47bd663361f2a5d82a073fbf7d7178e37b (diff) | |
send: account for route-based MTU
It might be that a particular route has a different MTU than the
interface, via `ip route add ... dev wg0 mtu 1281`, for example. In this
case, it's important that we don't accidently pad beyond the end of the
MTU. We accomplish that in this patch by carrying forward the MTU from
the dst if it exists. We also add a unit test for this issue.
Reported-by: Roman Mamedov <rm.wg@romanrm.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'src/device.c')
| -rw-r--r-- | src/device.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/src/device.c b/src/device.c index 1614d61..d64653d 100644 --- a/src/device.c +++ b/src/device.c @@ -120,6 +120,7 @@ static netdev_tx_t xmit(struct sk_buff *skb, struct net_device *dev) struct sk_buff *next; struct sk_buff_head packets; sa_family_t family; + u32 mtu; int ret; if (unlikely(skb_examine_untrusted_ip_hdr(skb) != skb->protocol)) { @@ -142,6 +143,8 @@ static netdev_tx_t xmit(struct sk_buff *skb, struct net_device *dev) goto err_peer; } + mtu = dst_mtu(skb_dst(skb)); + __skb_queue_head_init(&packets); if (!skb_is_gso(skb)) skb->next = NULL; @@ -168,6 +171,8 @@ static netdev_tx_t xmit(struct sk_buff *skb, struct net_device *dev) */ skb_dst_drop(skb); + PACKET_CB(skb)->mtu = mtu; + __skb_queue_tail(&packets, skb); } while ((skb = next) != NULL); |