diff options
| author | Eric Dumazet <edumazet@google.com> | 2023-07-19 06:47:54 +0000 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2023-07-20 12:49:40 +0200 |
| commit | b44693495af8f309b8ddec4b30833085d1c2d0c4 (patch) | |
| tree | 5ef6c99b79c43851bb837d7904fed7c6a2cab2f8 /net | |
| parent | af1e2cffbd2ef338b1d2e7318cb2516cc6380303 (diff) | |
tcp: add TCP_OLD_SEQUENCE drop reason
tcp_sequence() uses two conditions to decide to drop a packet,
and we currently report generic TCP_INVALID_SEQUENCE drop reason.
Duplicates are common, we need to distinguish them from
the other case.
I chose to not reuse TCP_OLD_DATA, and instead added
TCP_OLD_SEQUENCE drop reason.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230719064754.2794106-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_input.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index e2affdd147da..670c3dab24f2 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4312,10 +4312,16 @@ static inline bool tcp_paws_discard(const struct sock *sk, * (borrowed from freebsd) */ -static inline bool tcp_sequence(const struct tcp_sock *tp, u32 seq, u32 end_seq) +static enum skb_drop_reason tcp_sequence(const struct tcp_sock *tp, + u32 seq, u32 end_seq) { - return !before(end_seq, tp->rcv_wup) && - !after(seq, tp->rcv_nxt + tcp_receive_window(tp)); + if (before(end_seq, tp->rcv_wup)) + return SKB_DROP_REASON_TCP_OLD_SEQUENCE; + + if (after(seq, tp->rcv_nxt + tcp_receive_window(tp))) + return SKB_DROP_REASON_TCP_INVALID_SEQUENCE; + + return SKB_NOT_DROPPED_YET; } /* When we get a reset we do this. */ @@ -5738,7 +5744,8 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb, } /* Step 1: check sequence number */ - if (!tcp_sequence(tp, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq)) { + reason = tcp_sequence(tp, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq); + if (reason) { /* RFC793, page 37: "In all states except SYN-SENT, all reset * (RST) segments are validated by checking their SEQ-fields." * And page 69: "If an incoming segment is not acceptable, @@ -5755,7 +5762,6 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb, } else if (tcp_reset_check(sk, skb)) { goto reset; } - SKB_DR_SET(reason, TCP_INVALID_SEQUENCE); goto discard; } |