[Devel] [PATCH RHEL9 COMMIT] net: tcp: add skb drop reasons to tcp_v4_rcv()

[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 02d3236168eedad5dd47213a2ec7fc411091a94f
Author: Menglong Dong <imagedong at tencent.com>
Date:   Tue Jan 3 17:39:06 2023 +0200

    net: tcp: add skb drop reasons to tcp_v4_rcv()
    
    Use kfree_skb_reason() for some path in tcp_v4_rcv() that missed before,
    including:
    
    SKB_DROP_REASON_SOCKET_FILTER
    SKB_DROP_REASON_XFRM_POLICY
    
    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
---
 net/ipv4/tcp_ipv4.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 4af44bb8228c..0267b0cc1da0 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2043,6 +2043,8 @@ int tcp_v4_rcv(struct sk_buff *skb)
 			iph = ip_hdr(skb);
 			tcp_v4_fill_cb(skb, iph, th);
 			nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
+		} else {
+			drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
 		}
 		if (!nsk) {
 			reqsk_put(req);
@@ -2074,8 +2076,10 @@ int tcp_v4_rcv(struct sk_buff *skb)
 		goto discard_and_relse;
 	}
 
-	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
+	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
+		drop_reason = SKB_DROP_REASON_XFRM_POLICY;
 		goto discard_and_relse;
+	}
 
 	if (tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))
 		goto discard_and_relse;
@@ -2147,6 +2151,7 @@ int tcp_v4_rcv(struct sk_buff *skb)
 
 do_time_wait:
 	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
+		drop_reason = SKB_DROP_REASON_XFRM_POLICY;
 		inet_twsk_put(inet_twsk(sk));
 		goto discard_it;
 	}