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tcp: fix tcp_grow_skb() vs tstamps 

I forgot to call tcp_skb_collapse_tstamp() in the
case we consume the second skb in write queue.

Neal suggested to create a common helper used by tcp_mtu_probe()
and tcp_grow_skb().

Fixes: 8ee602c635 ("tcp: try to send bigger TSO packets")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Link: https://lore.kernel.org/r/20240425193450.411640-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2024-04-25 19:34:50 +00:00 committed by Jakub Kicinski
parent 8880e2666f
commit 1bede0a12d
1 changed files with 19 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
net/ipv4/tcp_output.c
View File

@ -2403,6 +2403,21 @@ commit:
return 0;
}
/* tcp_mtu_probe() and tcp_grow_skb() can both eat an skb (src) if
* all its payload was moved to another one (dst).
* Make sure to transfer tcp_flags, eor, and tstamp.
*/
static void tcp_eat_one_skb(struct sock *sk,
struct sk_buff *dst,
struct sk_buff *src)
{
TCP_SKB_CB(dst)->tcp_flags |= TCP_SKB_CB(src)->tcp_flags;
TCP_SKB_CB(dst)->eor = TCP_SKB_CB(src)->eor;
tcp_skb_collapse_tstamp(dst, src);
tcp_unlink_write_queue(src, sk);
tcp_wmem_free_skb(sk, src);
}
/* Create a new MTU probe if we are ready.
* MTU probe is regularly attempting to increase the path MTU by
* deliberately sending larger packets. This discovers routing
@ -2508,16 +2523,7 @@ static int tcp_mtu_probe(struct sock *sk)
copy = min_t(int, skb->len, probe_size - len);
if (skb->len <= copy) {
/* We've eaten all the data from this skb.
* Throw it away. */
TCP_SKB_CB(nskb)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
/* If this is the last SKB we copy and eor is set
* we need to propagate it to the new skb.
*/
TCP_SKB_CB(nskb)->eor = TCP_SKB_CB(skb)->eor;
tcp_skb_collapse_tstamp(nskb, skb);
tcp_unlink_write_queue(skb, sk);
tcp_wmem_free_skb(sk, skb);
tcp_eat_one_skb(sk, nskb, skb);
} else {
TCP_SKB_CB(nskb)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags &
~(TCPHDR_FIN|TCPHDR_PSH);
@ -2705,11 +2711,10 @@ static void tcp_grow_skb(struct sock *sk, struct sk_buff *skb, int amount)
TCP_SKB_CB(next_skb)->seq += nlen;
if (!next_skb->len) {
/* In case FIN is set, we need to update end_seq */
TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(next_skb)->end_seq;
TCP_SKB_CB(skb)->eor = TCP_SKB_CB(next_skb)->eor;
TCP_SKB_CB(skb)->tcp_flags |= TCP_SKB_CB(next_skb)->tcp_flags;
tcp_unlink_write_queue(next_skb, sk);
tcp_wmem_free_skb(sk, next_skb);
tcp_eat_one_skb(sk, skb, next_skb);
}
}