Commit 7a26dc9e authored by Menglong Dong's avatar Menglong Dong Committed by David S. Miller
Browse files

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: default avatarMengen Sun <mengensun@tencent.com>
Reviewed-by: default avatarHao Peng <flyingpeng@tencent.com>
Signed-off-by: default avatarMenglong Dong <imagedong@tencent.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 643b622b

include/linux/skbuff.h

+4 −0
Original line number Diff line number Diff line
@@ -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,

};

include/net/tcp.h

+2 −1
Original line number Diff line number Diff line
@@ -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);

include/trace/events/skb.h

+1 −0
Original line number Diff line number Diff line
@@ -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

net/ipv4/tcp_ipv4.c

+5 −2
Original line number Diff line number Diff line
@@ -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 @@ bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb) 


	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 @@ int tcp_v4_rcv(struct sk_buff *skb) 
	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);

net/ipv6/tcp_ipv6.c

+1 −1
Original line number Diff line number Diff line
@@ -1784,7 +1784,7 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb) 
	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);