From 7a26dc9e7b43f5a24c4b843713e728582adf1c38 Mon Sep 17 00:00:00 2001 From: Menglong Dong Date: Sun, 20 Feb 2022 15:06:33 +0800 Subject: [PATCH] net: tcp: add skb drop reasons to tcp_add_backlog() Pass the address of drop_reason to tcp_add_backlog() to store the reasons for skb drops when fails. Following drop reasons are introduced: SKB_DROP_REASON_SOCKET_BACKLOG Reviewed-by: Mengen Sun Reviewed-by: Hao Peng Signed-off-by: Menglong Dong Reviewed-by: Eric Dumazet Reviewed-by: David Ahern Signed-off-by: David S. Miller --- include/linux/skbuff.h | 4 ++++ include/net/tcp.h | 3 ++- include/trace/events/skb.h | 1 + net/ipv4/tcp_ipv4.c | 7 +++++-- net/ipv6/tcp_ipv6.c | 2 +- 5 files changed, 13 insertions(+), 4 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 46678eb587ff..f7f33c79945b 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -358,6 +358,10 @@ enum skb_drop_reason { * corresponding to * LINUX_MIB_TCPMD5FAILURE */ + SKB_DROP_REASON_SOCKET_BACKLOG, /* failed to add skb to socket + * backlog (see + * LINUX_MIB_TCPBACKLOGDROP) + */ SKB_DROP_REASON_MAX, }; diff --git a/include/net/tcp.h b/include/net/tcp.h index eff2487d972d..04f4650e0ff0 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1367,7 +1367,8 @@ static inline bool tcp_checksum_complete(struct sk_buff *skb) __skb_checksum_complete(skb); } -bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb); +bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb, + enum skb_drop_reason *reason); #ifdef CONFIG_INET void __sk_defer_free_flush(struct sock *sk); diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h index 46c06b0be850..bfccd77e9071 100644 --- a/include/trace/events/skb.h +++ b/include/trace/events/skb.h @@ -31,6 +31,7 @@ EM(SKB_DROP_REASON_TCP_MD5UNEXPECTED, \ TCP_MD5UNEXPECTED) \ EM(SKB_DROP_REASON_TCP_MD5FAILURE, TCP_MD5FAILURE) \ + EM(SKB_DROP_REASON_SOCKET_BACKLOG, SOCKET_BACKLOG) \ EMe(SKB_DROP_REASON_MAX, MAX) #undef EM diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index d3c417119057..cbca8637ba2f 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1811,7 +1811,8 @@ int tcp_v4_early_demux(struct sk_buff *skb) return 0; } -bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb) +bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb, + enum skb_drop_reason *reason) { u32 limit, tail_gso_size, tail_gso_segs; struct skb_shared_info *shinfo; @@ -1837,6 +1838,7 @@ bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb) if (unlikely(tcp_checksum_complete(skb))) { bh_unlock_sock(sk); trace_tcp_bad_csum(skb); + *reason = SKB_DROP_REASON_TCP_CSUM; __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS); __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); return true; @@ -1925,6 +1927,7 @@ no_coalesce: if (unlikely(sk_add_backlog(sk, skb, limit))) { bh_unlock_sock(sk); + *reason = SKB_DROP_REASON_SOCKET_BACKLOG; __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP); return true; } @@ -2133,7 +2136,7 @@ process: if (!sock_owned_by_user(sk)) { ret = tcp_v4_do_rcv(sk, skb); } else { - if (tcp_add_backlog(sk, skb)) + if (tcp_add_backlog(sk, skb, &drop_reason)) goto discard_and_relse; } bh_unlock_sock(sk); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 1262b790b146..abf0ad547858 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1784,7 +1784,7 @@ process: if (!sock_owned_by_user(sk)) { ret = tcp_v6_do_rcv(sk, skb); } else { - if (tcp_add_backlog(sk, skb)) + if (tcp_add_backlog(sk, skb, &drop_reason)) goto discard_and_relse; } bh_unlock_sock(sk); -- 2.11.0