[Devel] [PATCH RHEL9 COMMIT] net: tcp: use tcp_drop_reason() for tcp_rcv_established()

[Konstantin Khorenko]

The commit is pushed to "branch-rh9-5.14.0-162.6.1.vz9.18.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh9-5.14.0-162.6.1.vz9.18.2
------>
commit 8847f70af35315a5f7898bfb9e3a1f25e428ee88
Author: Menglong Dong <imagedong at tencent.com>
Date:   Tue Jan 3 17:39:11 2023 +0200

    net: tcp: use tcp_drop_reason() for tcp_rcv_established()
    
    Replace tcp_drop() used in tcp_rcv_established() with tcp_drop_reason().
    Following drop reasons are added:
    
    SKB_DROP_REASON_TCP_FLAGS
    
    Reviewed-by: Mengen Sun <mengensun at tencent.com>
    Reviewed-by: Hao Peng <flyingpeng at tencent.com>
    Signed-off-by: Menglong Dong <imagedong at tencent.com>
    Reviewed-by: Eric Dumazet <edumazet at google.com>
    Reviewed-by: David Ahern <dsahern at kernel.org>
    Signed-off-by: David S. Miller <davem at davemloft.net>
    Acked-by: Nikolay Borisov <nborisov at suse.com>
    Signed-off-by: Nikolay Borisov <nikolay.borisov at virtuozzo.com>
    
    ======
    Patchset description:
    ms/net: Annotate skb free sites with reason
    
    This series backports most of the patches that add a reason to skb free sites.
    
    https://jira.sw.ru/browse/PSBM-143302
    
    Feature: net: improve verbosity of dropped packets reporting
---
 include/linux/skbuff.h     | 6 +-----
 include/trace/events/skb.h | 1 +
 net/ipv4/tcp_input.c       | 9 +++++++--
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 700996e9987a..8febe5c6cb47 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -360,11 +360,7 @@ enum skb_drop_reason {
 					 * backlog (see
 					 * LINUX_MIB_TCPBACKLOGDROP)
 					 */
-
-
-
-
-
+	SKB_DROP_REASON_TCP_FLAGS,      /* TCP flags invalid */
 
 	SKB_DROP_REASON_MAX,
 };
diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index 841d0bfebf73..792e2ff696f7 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -32,6 +32,7 @@
 	   TCP_MD5UNEXPECTED)                                   \
 	EM(SKB_DROP_REASON_TCP_MD5FAILURE, TCP_MD5FAILURE)      \
 	EM(SKB_DROP_REASON_SOCKET_BACKLOG, SOCKET_BACKLOG)      \
+	EM(SKB_DROP_REASON_TCP_FLAGS, TCP_FLAGS)		\
 	EMe(SKB_DROP_REASON_MAX, MAX)
 
 #undef EM
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 09effcf4db7c..7e65ba089bf0 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5749,6 +5749,7 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
  */
 void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
 {
+	enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
 	const struct tcphdr *th = (const struct tcphdr *)skb->data;
 	struct tcp_sock *tp = tcp_sk(sk);
 	unsigned int len = skb->len;
@@ -5837,6 +5838,7 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
 				tp->rcv_rtt_last_tsecr = tp->rx_opt.rcv_tsecr;
 				return;
 			} else { /* Header too small */
+				reason = SKB_DROP_REASON_PKT_TOO_SMALL;
 				TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
 				goto discard;
 			}
@@ -5892,8 +5894,10 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
 	if (len < (th->doff << 2) || tcp_checksum_complete(skb))
 		goto csum_error;
 
-	if (!th->ack && !th->rst && !th->syn)
+	if (!th->ack && !th->rst && !th->syn) {
+		reason = SKB_DROP_REASON_TCP_FLAGS;
 		goto discard;
+	}
 
 	/*
 	 *	Standard slow path.
@@ -5919,12 +5923,13 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
 	return;
 
 csum_error:
+	reason = SKB_DROP_REASON_TCP_CSUM;
 	trace_tcp_bad_csum(skb);
 	TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
 	TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
 
 discard:
-	tcp_drop(sk, skb);
+	tcp_drop_reason(sk, skb, reason);
 }
 EXPORT_SYMBOL(tcp_rcv_established);