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Commit 2ad55f56 authored by Yuchung Cheng's avatar Yuchung Cheng Committed by David S. Miller
Browse files

tcp: new helper tcp_timeout_mark_lost 



Refactor using a new helper, tcp_timeout_mark_loss(), that marks packets
lost upon RTO.

Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: default avatarPriyaranjan Jha <priyarjha@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d716bfdb

net/ipv4/tcp_input.c

+29 −21
Original line number Diff line number Diff line
@@ -1917,18 +1917,43 @@ static inline void tcp_init_undo(struct tcp_sock *tp) 
	tp->undo_retrans = tp->retrans_out ? : -1;

}



/* Enter Loss state. If we detect SACK reneging, forget all SACK information

/* If we detect SACK reneging, forget all SACK information

 * and reset tags completely, otherwise preserve SACKs. If receiver

 * dropped its ofo queue, we will know this due to reneging detection.

 */

static void tcp_timeout_mark_lost(struct sock *sk)

{

	struct tcp_sock *tp = tcp_sk(sk);

	struct sk_buff *skb;

	bool is_reneg;			/* is receiver reneging on SACKs? */



	skb = tcp_rtx_queue_head(sk);

	is_reneg = skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED);

	if (is_reneg) {

		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSACKRENEGING);

		tp->sacked_out = 0;

		/* Mark SACK reneging until we recover from this loss event. */

		tp->is_sack_reneg = 1;

	} else if (tcp_is_reno(tp)) {

		tcp_reset_reno_sack(tp);

	}



	skb_rbtree_walk_from(skb) {

		if (is_reneg)

			TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_ACKED;

		tcp_mark_skb_lost(sk, skb);

	}

	tcp_verify_left_out(tp);

	tcp_clear_all_retrans_hints(tp);

}



/* Enter Loss state. */

void tcp_enter_loss(struct sock *sk)

{

	const struct inet_connection_sock *icsk = inet_csk(sk);

	struct tcp_sock *tp = tcp_sk(sk);

	struct net *net = sock_net(sk);

	struct sk_buff *skb;

	bool new_recovery = icsk->icsk_ca_state < TCP_CA_Recovery;

	bool is_reneg;			/* is receiver reneging on SACKs? */



	/* Reduce ssthresh if it has not yet been made inside this window. */

	if (icsk->icsk_ca_state <= TCP_CA_Disorder ||
@@ -1944,24 +1969,7 @@ void tcp_enter_loss(struct sock *sk) 
	tp->snd_cwnd_cnt   = 0;

	tp->snd_cwnd_stamp = tcp_jiffies32;



	if (tcp_is_reno(tp))

		tcp_reset_reno_sack(tp);



	skb = tcp_rtx_queue_head(sk);

	is_reneg = skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED);

	if (is_reneg) {

		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSACKRENEGING);

		tp->sacked_out = 0;

		/* Mark SACK reneging until we recover from this loss event. */

		tp->is_sack_reneg = 1;

	}

	skb_rbtree_walk_from(skb) {

		if (is_reneg)

			TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_ACKED;

		tcp_mark_skb_lost(sk, skb);

	}

	tcp_verify_left_out(tp);

	tcp_clear_all_retrans_hints(tp);

	tcp_timeout_mark_lost(sk);



	/* Timeout in disordered state after receiving substantial DUPACKs

	 * suggests that the degree of reordering is over-estimated.