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Commit a6df1ae9 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp: add OFO snmp counters 



Add three SNMP TCP counters, to better track TCP behavior
at global stage (netstat -s), when packets are received
Out Of Order (OFO)

TCPOFOQueue : Number of packets queued in OFO queue

TCPOFODrop  : Number of packets meant to be queued in OFO
              but dropped because socket rcvbuf limit hit.

TCPOFOMerge : Number of packets in OFO that were merged with
              other packets.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 141e369d

include/linux/snmp.h

+4 −1
Original line number Diff line number Diff line
@@ -234,6 +234,9 @@ enum 
	LINUX_MIB_TCPREQQFULLDROP,		/* TCPReqQFullDrop */

	LINUX_MIB_TCPRETRANSFAIL,		/* TCPRetransFail */

	LINUX_MIB_TCPRCVCOALESCE,		/* TCPRcvCoalesce */

	LINUX_MIB_TCPOFOQUEUE,			/* TCPOFOQueue */

	LINUX_MIB_TCPOFODROP,			/* TCPOFODrop */

	LINUX_MIB_TCPOFOMERGE,			/* TCPOFOMerge */

	__LINUX_MIB_MAX

};

net/ipv4/proc.c

+3 −0
Original line number Diff line number Diff line
@@ -258,6 +258,9 @@ static const struct snmp_mib snmp4_net_list[] = { 
	SNMP_MIB_ITEM("TCPReqQFullDrop", LINUX_MIB_TCPREQQFULLDROP),

	SNMP_MIB_ITEM("TCPRetransFail", LINUX_MIB_TCPRETRANSFAIL),

	SNMP_MIB_ITEM("TCPRcvCoalesce", LINUX_MIB_TCPRCVCOALESCE),

	SNMP_MIB_ITEM("TCPOFOQueue", LINUX_MIB_TCPOFOQUEUE),

	SNMP_MIB_ITEM("TCPOFODrop", LINUX_MIB_TCPOFODROP),

	SNMP_MIB_ITEM("TCPOFOMerge", LINUX_MIB_TCPOFOMERGE),

	SNMP_MIB_SENTINEL

};

net/ipv4/tcp_input.c

+5 −2
Original line number Diff line number Diff line
@@ -4397,8 +4397,8 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) 


	TCP_ECN_check_ce(tp, skb);



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

		/* TODO: should increment a counter */

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

		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPOFODROP);

		__kfree_skb(skb);

		return;

	}
@@ -4407,6 +4407,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) 
	tp->pred_flags = 0;

	inet_csk_schedule_ack(sk);



	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPOFOQUEUE);

	SOCK_DEBUG(sk, "out of order segment: rcv_next %X seq %X - %X\n",

		   tp->rcv_nxt, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
@@ -4460,6 +4461,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) 
	if (skb1 && before(seq, TCP_SKB_CB(skb1)->end_seq)) {

		if (!after(end_seq, TCP_SKB_CB(skb1)->end_seq)) {

			/* All the bits are present. Drop. */

			NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPOFOMERGE);

			__kfree_skb(skb);

			skb = NULL;

			tcp_dsack_set(sk, seq, end_seq);
@@ -4498,6 +4500,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) 
		__skb_unlink(skb1, &tp->out_of_order_queue);

		tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq,

				 TCP_SKB_CB(skb1)->end_seq);

		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPOFOMERGE);

		__kfree_skb(skb1);

	}