forked from Minki/linux
33 lines
965 B
C
33 lines
965 B
C
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#include <linux/tcp.h>
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#include <net/tcp.h>
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/* Record the most recently (re)sent time among the (s)acked packets */
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void tcp_rack_advance(struct tcp_sock *tp,
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const struct skb_mstamp *xmit_time, u8 sacked)
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{
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if (tp->rack.mstamp.v64 &&
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!skb_mstamp_after(xmit_time, &tp->rack.mstamp))
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return;
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if (sacked & TCPCB_RETRANS) {
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struct skb_mstamp now;
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/* If the sacked packet was retransmitted, it's ambiguous
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* whether the retransmission or the original (or the prior
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* retransmission) was sacked.
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*
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* If the original is lost, there is no ambiguity. Otherwise
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* we assume the original can be delayed up to aRTT + min_rtt.
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* the aRTT term is bounded by the fast recovery or timeout,
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* so it's at least one RTT (i.e., retransmission is at least
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* an RTT later).
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*/
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skb_mstamp_get(&now);
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if (skb_mstamp_us_delta(&now, xmit_time) < tcp_min_rtt(tp))
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return;
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}
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tp->rack.mstamp = *xmit_time;
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tp->rack.advanced = 1;
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}
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