tcp: fix false undo corner cases

[android-x86/kernel.git] / net / ipv4 / tcp_input.c

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 40661fc..40639c2 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1106,7 +1106,7 @@ static bool tcp_check_dsack(struct sock *sk, const struct sk_buff *ack_skb,
        }
 
        /* D-SACK for already forgotten data... Do dumb counting. */
-       if (dup_sack && tp->undo_marker && tp->undo_retrans &&
+       if (dup_sack && tp->undo_marker && tp->undo_retrans > 0 &&
            !after(end_seq_0, prior_snd_una) &&
            after(end_seq_0, tp->undo_marker))
                tp->undo_retrans--;
@@ -1162,7 +1162,7 @@ static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb,
                        unsigned int new_len = (pkt_len / mss) * mss;
                        if (!in_sack && new_len < pkt_len) {
                                new_len += mss;
-                               if (new_len > skb->len)
+                               if (new_len >= skb->len)
                                        return 0;
                        }
                        pkt_len = new_len;
@@ -1187,7 +1187,7 @@ static u8 tcp_sacktag_one(struct sock *sk,
 
        /* Account D-SACK for retransmitted packet. */
        if (dup_sack && (sacked & TCPCB_RETRANS)) {
-               if (tp->undo_marker && tp->undo_retrans &&
+               if (tp->undo_marker && tp->undo_retrans > 0 &&
                    after(end_seq, tp->undo_marker))
                        tp->undo_retrans--;
                if (sacked & TCPCB_SACKED_ACKED)
@@ -1893,7 +1893,7 @@ static void tcp_clear_retrans_partial(struct tcp_sock *tp)
        tp->lost_out = 0;
 
        tp->undo_marker = 0;
-       tp->undo_retrans = 0;
+       tp->undo_retrans = -1;
 }
 
 void tcp_clear_retrans(struct tcp_sock *tp)
@@ -2665,7 +2665,7 @@ static void tcp_enter_recovery(struct sock *sk, bool ece_ack)
 
        tp->prior_ssthresh = 0;
        tp->undo_marker = tp->snd_una;
-       tp->undo_retrans = tp->retrans_out;
+       tp->undo_retrans = tp->retrans_out ? : -1;
 
        if (inet_csk(sk)->icsk_ca_state < TCP_CA_CWR) {
                if (!ece_ack)