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authorEric Dumazet <edumazet@google.com>2022-04-15 17:10:41 -0700
committerDavid S. Miller <davem@davemloft.net>2022-04-17 13:31:31 +0100
commitda40b613f89c43c58986e6f30560ad6573a4d569 (patch)
treea699f265917164364a0f3ba7cb33c4fc1c67199b
parentb5ec1e6205a1cb719ab188472f00ae81b0800f2e (diff)
downloadnet-next-da40b613f89c43c58986e6f30560ad6573a4d569.tar.gz
tcp: add drop reason support to tcp_validate_incoming()
Creates four new drop reasons for the following cases: 1) packet being rejected by RFC 7323 PAWS check 2) packet being rejected by SEQUENCE check 3) Invalid RST packet 4) Invalid SYN packet Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/skbuff.h6
-rw-r--r--include/trace/events/skb.h5
-rw-r--r--net/ipv4/tcp_input.c7
3 files changed, 17 insertions, 1 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 0ef11df1bc67f2..a903da1fa0ed89 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -381,6 +381,12 @@ enum skb_drop_reason {
* the ofo queue, corresponding to
* LINUX_MIB_TCPOFOMERGE
*/
+ SKB_DROP_REASON_TCP_RFC7323_PAWS, /* PAWS check, corresponding to
+ * LINUX_MIB_PAWSESTABREJECTED
+ */
+ 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_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 2da72a9a576462..820dacd14bad9e 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -37,6 +37,11 @@
EM(SKB_DROP_REASON_TCP_OLD_DATA, TCP_OLD_DATA) \
EM(SKB_DROP_REASON_TCP_OVERWINDOW, TCP_OVERWINDOW) \
EM(SKB_DROP_REASON_TCP_OFOMERGE, TCP_OFOMERGE) \
+ EM(SKB_DROP_REASON_TCP_RFC7323_PAWS, TCP_RFC7323_PAWS) \
+ EM(SKB_DROP_REASON_TCP_INVALID_SEQUENCE, \
+ 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_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 b2d5fbef6ce3ba..9a1cb3f48c3fb2 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5667,6 +5667,7 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
const struct tcphdr *th, int syn_inerr)
{
struct tcp_sock *tp = tcp_sk(sk);
+ SKB_DR(reason);
/* RFC1323: H1. Apply PAWS check first. */
if (tcp_fast_parse_options(sock_net(sk), skb, th, tp) &&
@@ -5678,6 +5679,7 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
LINUX_MIB_TCPACKSKIPPEDPAWS,
&tp->last_oow_ack_time))
tcp_send_dupack(sk, skb);
+ SKB_DR_SET(reason, TCP_RFC7323_PAWS);
goto discard;
}
/* Reset is accepted even if it did not pass PAWS. */
@@ -5701,6 +5703,7 @@ 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;
}
@@ -5743,6 +5746,7 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
sk->sk_state == TCP_ESTABLISHED)
tcp_fastopen_active_disable(sk);
tcp_send_challenge_ack(sk);
+ SKB_DR_SET(reason, TCP_RESET);
goto discard;
}
@@ -5757,6 +5761,7 @@ syn_challenge:
TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSYNCHALLENGE);
tcp_send_challenge_ack(sk);
+ SKB_DR_SET(reason, TCP_INVALID_SYN);
goto discard;
}
@@ -5765,7 +5770,7 @@ syn_challenge:
return true;
discard:
- tcp_drop(sk, skb);
+ tcp_drop_reason(sk, skb, reason);
return false;
reset: