tcp: add drop reasons to tcp_rcv_state_process()

Add basic support for drop reasons in tcp_rcv_state_process()

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 a903da1..6f1410b 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -387,6 +387,9 @@ enum skb_drop_reason {
        SKB_DROP_REASON_TCP_INVALID_SEQUENCE, /* Not acceptable SEQ field */
        SKB_DROP_REASON_TCP_RESET,      /* Invalid RST packet */
        SKB_DROP_REASON_TCP_INVALID_SYN, /* Incoming packet has unexpected SYN flag */
+       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_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 820dacd..fbe21ad 100644 (file)
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -42,6 +42,9 @@
           TCP_INVALID_SEQUENCE)                                \
        EM(SKB_DROP_REASON_TCP_RESET, TCP_RESET)                \
        EM(SKB_DROP_REASON_TCP_INVALID_SYN, TCP_INVALID_SYN)    \
+       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_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 f95a836..85fae79 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6413,21 +6413,26 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
        struct request_sock *req;
        int queued = 0;
        bool acceptable;
+       SKB_DR(reason);
 
        switch (sk->sk_state) {
        case TCP_CLOSE:
+               SKB_DR_SET(reason, TCP_CLOSE);
                goto discard;
 
        case TCP_LISTEN:
                if (th->ack)
                        return 1;
 
-               if (th->rst)
+               if (th->rst) {
+                       SKB_DR_SET(reason, TCP_RESET);
                        goto discard;
-
+               }
                if (th->syn) {
-                       if (th->fin)
+                       if (th->fin) {
+                               SKB_DR_SET(reason, TCP_FLAGS);
                                goto discard;
+                       }
                        /* It is possible that we process SYN packets from backlog,
                         * so we need to make sure to disable BH and RCU right there.
                         */
@@ -6442,6 +6447,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
                        consume_skb(skb);
                        return 0;
                }
+               SKB_DR_SET(reason, TCP_FLAGS);
                goto discard;
 
        case TCP_SYN_SENT:
@@ -6468,13 +6474,16 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
                WARN_ON_ONCE(sk->sk_state != TCP_SYN_RECV &&
                    sk->sk_state != TCP_FIN_WAIT1);
 
-               if (!tcp_check_req(sk, skb, req, true, &req_stolen))
+               if (!tcp_check_req(sk, skb, req, true, &req_stolen)) {
+                       SKB_DR_SET(reason, TCP_FASTOPEN);
                        goto discard;
+               }
        }
 
-       if (!th->ack && !th->rst && !th->syn)
+       if (!th->ack && !th->rst && !th->syn) {
+               SKB_DR_SET(reason, TCP_FLAGS);
                goto discard;
-
+       }
        if (!tcp_validate_incoming(sk, skb, th, 0))
                return 0;
 
@@ -6487,6 +6496,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
                if (sk->sk_state == TCP_SYN_RECV)
                        return 1;       /* send one RST */
                tcp_send_challenge_ack(sk);
+               SKB_DR_SET(reason, TCP_OLD_ACK);
                goto discard;
        }
        switch (sk->sk_state) {
@@ -6647,7 +6657,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
 
        if (!queued) {
 discard:
-               tcp_drop(sk, skb);
+               tcp_drop_reason(sk, skb, reason);
        }
        return 0;