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Commit b8fef65a authored by Yuchung Cheng's avatar Yuchung Cheng Committed by David S. Miller
Browse files

tcp: new helper tcp_rack_skb_timeout 



Create and export a new helper tcp_rack_skb_timeout and move tcp_is_rack
to prepare the final RTO change.

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 c77d62ff

include/net/tcp.h

+2 −0
Original line number Diff line number Diff line
@@ -1879,6 +1879,8 @@ void tcp_init(void); 
/* tcp_recovery.c */

void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb);

void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced);

extern s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb,

				u32 reo_wnd);

extern void tcp_rack_mark_lost(struct sock *sk);

extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq,

			     u64 xmit_time);

net/ipv4/tcp_input.c

+5 −5
Original line number Diff line number Diff line
@@ -1917,6 +1917,11 @@ static inline void tcp_init_undo(struct tcp_sock *tp) 
	tp->undo_retrans = tp->retrans_out ? : -1;

}



static bool tcp_is_rack(const struct sock *sk)

{

	return sock_net(sk)->ipv4.sysctl_tcp_recovery & TCP_RACK_LOSS_DETECTION;

}



/* 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.
@@ -2031,11 +2036,6 @@ static inline int tcp_dupack_heuristics(const struct tcp_sock *tp) 
	return tp->sacked_out + 1;

}



static bool tcp_is_rack(const struct sock *sk)

{

	return sock_net(sk)->ipv4.sysctl_tcp_recovery & TCP_RACK_LOSS_DETECTION;

}



/* Linux NewReno/SACK/ECN state machine.

 * --------------------------------------

 *

net/ipv4/tcp_recovery.c

+7 −2
Original line number Diff line number Diff line
@@ -47,6 +47,12 @@ u32 tcp_rack_reo_wnd(const struct sock *sk) 
		   tp->srtt_us >> 3);

}



s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, u32 reo_wnd)

{

	return tp->rack.rtt_us + reo_wnd -

	       tcp_stamp_us_delta(tp->tcp_mstamp, skb->skb_mstamp);

}



/* RACK loss detection (IETF draft draft-ietf-tcpm-rack-01):

 *

 * Marks a packet lost, if some packet sent later has been (s)acked.
@@ -92,8 +98,7 @@ static void tcp_rack_detect_loss(struct sock *sk, u32 *reo_timeout) 
		/* A packet is lost if it has not been s/acked beyond

		 * the recent RTT plus the reordering window.

		 */

		remaining = tp->rack.rtt_us + reo_wnd -

			    tcp_stamp_us_delta(tp->tcp_mstamp, skb->skb_mstamp);

		remaining = tcp_rack_skb_timeout(tp, skb, reo_wnd);

		if (remaining <= 0) {

			tcp_mark_skb_lost(sk, skb);

			list_del_init(&skb->tcp_tsorted_anchor);