tcp: add two drop reasons for tcp_ack()

Add TCP_TOO_OLD_ACK and TCP_ACK_UNSENT_DATA drop
reasons so that tcp_rcv_established() can report
them.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 6f1410b..9ff5557 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -390,6 +390,8 @@ enum skb_drop_reason {
        SKB_DROP_REASON_TCP_CLOSE,      /* TCP socket in CLOSE state */
        SKB_DROP_REASON_TCP_FASTOPEN,   /* dropped by FASTOPEN request socket */
        SKB_DROP_REASON_TCP_OLD_ACK,    /* TCP ACK is old, but in window */
+       SKB_DROP_REASON_TCP_TOO_OLD_ACK, /* TCP ACK is too old */
+       SKB_DROP_REASON_TCP_ACK_UNSENT_DATA, /* TCP ACK for data we haven't sent yet */
        SKB_DROP_REASON_IP_OUTNOROUTES, /* route lookup failed */
        SKB_DROP_REASON_BPF_CGROUP_EGRESS,      /* dropped by
                                                 * BPF_PROG_TYPE_CGROUP_SKB

diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index fbe21ad..eab0b09 100644 (file)
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -45,6 +45,9 @@
        EM(SKB_DROP_REASON_TCP_CLOSE, TCP_CLOSE)                \
        EM(SKB_DROP_REASON_TCP_FASTOPEN, TCP_FASTOPEN)          \
        EM(SKB_DROP_REASON_TCP_OLD_ACK, TCP_OLD_ACK)            \
+       EM(SKB_DROP_REASON_TCP_TOO_OLD_ACK, TCP_TOO_OLD_ACK)    \
+       EM(SKB_DROP_REASON_TCP_ACK_UNSENT_DATA,                 \
+          TCP_ACK_UNSENT_DATA)                                 \
        EM(SKB_DROP_REASON_IP_OUTNOROUTES, IP_OUTNOROUTES)      \
        EM(SKB_DROP_REASON_BPF_CGROUP_EGRESS,                   \
           BPF_CGROUP_EGRESS)                                   \

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 85fae79..8a68785 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3766,7 +3766,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
                if (before(ack, prior_snd_una - tp->max_window)) {
                        if (!(flag & FLAG_NO_CHALLENGE_ACK))
                                tcp_send_challenge_ack(sk);
-                       return -1;
+                       return -SKB_DROP_REASON_TCP_TOO_OLD_ACK;
                }
                goto old_ack;
        }
@@ -3775,7 +3775,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
         * this segment (RFC793 Section 3.9).
         */
        if (after(ack, tp->snd_nxt))
-               return -1;
+               return -SKB_DROP_REASON_TCP_ACK_UNSENT_DATA;
 
        if (after(ack, prior_snd_una)) {
                flag |= FLAG_SND_UNA_ADVANCED;
@@ -5962,7 +5962,8 @@ slow_path:
                return;
 
 step5:
-       if (tcp_ack(sk, skb, FLAG_SLOWPATH | FLAG_UPDATE_TS_RECENT) < 0)
+       reason = tcp_ack(sk, skb, FLAG_SLOWPATH | FLAG_UPDATE_TS_RECENT);
+       if (reason < 0)
                goto discard;
 
        tcp_rcv_rtt_measure_ts(sk, skb);