Commit a7ec3810 authored by Menglong Dong's avatar Menglong Dong Committed by David S. Miller
Browse files

net: tcp: use tcp_drop_reason() for tcp_data_queue() 



Replace tcp_drop() used in tcp_data_queue() with tcp_drop_reason().
Following drop reasons are introduced:

SKB_DROP_REASON_TCP_ZEROWINDOW
SKB_DROP_REASON_TCP_OLD_DATA
SKB_DROP_REASON_TCP_OVERWINDOW

SKB_DROP_REASON_TCP_OLD_DATA is used for the case that end_seq of skb
less than the left edges of receive window. (Maybe there is a better
name?)

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 2a968ef6

include/linux/skbuff.h

+13 −0
Original line number Diff line number Diff line
@@ -363,6 +363,19 @@ enum skb_drop_reason { 
					 * LINUX_MIB_TCPBACKLOGDROP)

					 */

	SKB_DROP_REASON_TCP_FLAGS,	/* TCP flags invalid */

	SKB_DROP_REASON_TCP_ZEROWINDOW,	/* TCP receive window size is zero,

					 * see LINUX_MIB_TCPZEROWINDOWDROP

					 */

	SKB_DROP_REASON_TCP_OLD_DATA,	/* the TCP data reveived is already

					 * received before (spurious retrans

					 * may happened), see

					 * LINUX_MIB_DELAYEDACKLOST

					 */

	SKB_DROP_REASON_TCP_OVERWINDOW,	/* the TCP data is out of window,

					 * the seq of the first byte exceed

					 * the right edges of receive

					 * window

					 */

	SKB_DROP_REASON_MAX,

};

include/trace/events/skb.h

+3 −0
Original line number Diff line number Diff line
@@ -33,6 +33,9 @@ 
	EM(SKB_DROP_REASON_TCP_MD5FAILURE, TCP_MD5FAILURE)	\

	EM(SKB_DROP_REASON_SOCKET_BACKLOG, SOCKET_BACKLOG)	\

	EM(SKB_DROP_REASON_TCP_FLAGS, TCP_FLAGS)		\

	EM(SKB_DROP_REASON_TCP_ZEROWINDOW, TCP_ZEROWINDOW)	\

	EM(SKB_DROP_REASON_TCP_OLD_DATA, TCP_OLD_DATA)		\

	EM(SKB_DROP_REASON_TCP_OVERWINDOW, TCP_OVERWINDOW)	\

	EMe(SKB_DROP_REASON_MAX, MAX)



#undef EM

net/ipv4/tcp_input.c

+11 −2
Original line number Diff line number Diff line
@@ -4988,6 +4988,7 @@ void tcp_data_ready(struct sock *sk) 
static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)

{

	struct tcp_sock *tp = tcp_sk(sk);

	enum skb_drop_reason reason;

	bool fragstolen;

	int eaten;
@@ -5006,6 +5007,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) 
	skb_dst_drop(skb);

	__skb_pull(skb, tcp_hdr(skb)->doff * 4);



	reason = SKB_DROP_REASON_NOT_SPECIFIED;

	tp->rx_opt.dsack = 0;



	/*  Queue data for delivery to the user.
@@ -5014,6 +5016,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) 
	 */

	if (TCP_SKB_CB(skb)->seq == tp->rcv_nxt) {

		if (tcp_receive_window(tp) == 0) {

			reason = SKB_DROP_REASON_TCP_ZEROWINDOW;

			NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPZEROWINDOWDROP);

			goto out_of_window;

		}
@@ -5023,6 +5026,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) 
		if (skb_queue_len(&sk->sk_receive_queue) == 0)

			sk_forced_mem_schedule(sk, skb->truesize);

		else if (tcp_try_rmem_schedule(sk, skb, skb->truesize)) {

			reason = SKB_DROP_REASON_PROTO_MEM;

			NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP);

			sk->sk_data_ready(sk);

			goto drop;
@@ -5059,6 +5063,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) 
	if (!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt)) {

		tcp_rcv_spurious_retrans(sk, skb);

		/* A retransmit, 2nd most common case.  Force an immediate ack. */

		reason = SKB_DROP_REASON_TCP_OLD_DATA;

		NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKLOST);

		tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
@@ -5066,13 +5071,16 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) 
		tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS);

		inet_csk_schedule_ack(sk);

drop:

		tcp_drop(sk, skb);

		tcp_drop_reason(sk, skb, reason);

		return;

	}



	/* Out of window. F.e. zero window probe. */

	if (!before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt + tcp_receive_window(tp)))

	if (!before(TCP_SKB_CB(skb)->seq,

		    tp->rcv_nxt + tcp_receive_window(tp))) {

		reason = SKB_DROP_REASON_TCP_OVERWINDOW;

		goto out_of_window;

	}



	if (before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) {

		/* Partial packet, seq < rcv_next < end_seq */
@@ -5082,6 +5090,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) 
		 * remembering D-SACK for its head made in previous line.

		 */

		if (!tcp_receive_window(tp)) {

			reason = SKB_DROP_REASON_TCP_ZEROWINDOW;

			NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPZEROWINDOWDROP);

			goto out_of_window;

		}