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[TCP]: Create tcp_sacktag_one().
Worker function that implements the main logic of the inner-most loop of tcp_sacktag_write_queue(). Idea was originally presented by David S. Miller. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ilpo Järvinen
David S. Miller
parent
b7d4815f35
commit
9e10c47cb9
@ -1240,6 +1240,99 @@ static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb,
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return in_sack;
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}
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static int tcp_sacktag_one(struct sk_buff *skb, struct tcp_sock *tp,
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int *reord, int dup_sack, int fack_count)
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{
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u8 sacked = TCP_SKB_CB(skb)->sacked;
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int flag = 0;
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/* Account D-SACK for retransmitted packet. */
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if (dup_sack && (sacked & TCPCB_RETRANS)) {
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if (after(TCP_SKB_CB(skb)->end_seq, tp->undo_marker))
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tp->undo_retrans--;
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if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una) &&
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(sacked & TCPCB_SACKED_ACKED))
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*reord = min(fack_count, *reord);
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}
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/* Nothing to do; acked frame is about to be dropped (was ACKed). */
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if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una))
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return flag;
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if (!(sacked & TCPCB_SACKED_ACKED)) {
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if (sacked & TCPCB_SACKED_RETRANS) {
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/* If the segment is not tagged as lost,
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* we do not clear RETRANS, believing
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* that retransmission is still in flight.
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*/
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if (sacked & TCPCB_LOST) {
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TCP_SKB_CB(skb)->sacked &=
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~(TCPCB_LOST|TCPCB_SACKED_RETRANS);
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tp->lost_out -= tcp_skb_pcount(skb);
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tp->retrans_out -= tcp_skb_pcount(skb);
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/* clear lost hint */
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tp->retransmit_skb_hint = NULL;
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}
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} else {
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if (!(sacked & TCPCB_RETRANS)) {
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/* New sack for not retransmitted frame,
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* which was in hole. It is reordering.
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*/
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if (before(TCP_SKB_CB(skb)->seq,
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tcp_highest_sack_seq(tp)))
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*reord = min(fack_count, *reord);
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/* SACK enhanced F-RTO (RFC4138; Appendix B) */
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if (!after(TCP_SKB_CB(skb)->end_seq, tp->frto_highmark))
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flag |= FLAG_ONLY_ORIG_SACKED;
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}
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if (sacked & TCPCB_LOST) {
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TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
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tp->lost_out -= tcp_skb_pcount(skb);
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/* clear lost hint */
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tp->retransmit_skb_hint = NULL;
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}
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}
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TCP_SKB_CB(skb)->sacked |= TCPCB_SACKED_ACKED;
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flag |= FLAG_DATA_SACKED;
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tp->sacked_out += tcp_skb_pcount(skb);
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fack_count += tcp_skb_pcount(skb);
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/* Lost marker hint past SACKed? Tweak RFC3517 cnt */
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if (!tcp_is_fack(tp) && (tp->lost_skb_hint != NULL) &&
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before(TCP_SKB_CB(skb)->seq,
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TCP_SKB_CB(tp->lost_skb_hint)->seq))
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tp->lost_cnt_hint += tcp_skb_pcount(skb);
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if (fack_count > tp->fackets_out)
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tp->fackets_out = fack_count;
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if (after(TCP_SKB_CB(skb)->seq, tcp_highest_sack_seq(tp)))
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tp->highest_sack = skb;
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} else {
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if (dup_sack && (sacked & TCPCB_RETRANS))
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*reord = min(fack_count, *reord);
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}
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/* D-SACK. We can detect redundant retransmission in S|R and plain R
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* frames and clear it. undo_retrans is decreased above, L|R frames
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* are accounted above as well.
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*/
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if (dup_sack && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS)) {
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TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
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tp->retrans_out -= tcp_skb_pcount(skb);
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tp->retransmit_skb_hint = NULL;
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}
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return flag;
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}
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static int
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tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_una)
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{
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@ -1375,7 +1468,6 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
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tcp_for_write_queue_from(skb, sk) {
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int in_sack = 0;
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u8 sacked;
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if (skb == tcp_send_head(sk))
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break;
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@ -1413,102 +1505,10 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
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if (unlikely(in_sack < 0))
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break;
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if (!in_sack) {
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fack_count += tcp_skb_pcount(skb);
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continue;
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}
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if (in_sack)
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flag |= tcp_sacktag_one(skb, tp, &reord, dup_sack, fack_count);
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sacked = TCP_SKB_CB(skb)->sacked;
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/* Account D-SACK for retransmitted packet. */
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if (dup_sack && (sacked & TCPCB_RETRANS)) {
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if (after(TCP_SKB_CB(skb)->end_seq, tp->undo_marker))
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tp->undo_retrans--;
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if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una) &&
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(sacked & TCPCB_SACKED_ACKED))
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reord = min(fack_count, reord);
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}
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/* Nothing to do; acked frame is about to be dropped (was ACKed). */
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if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una)) {
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fack_count += tcp_skb_pcount(skb);
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continue;
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}
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if (!(sacked&TCPCB_SACKED_ACKED)) {
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if (sacked & TCPCB_SACKED_RETRANS) {
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/* If the segment is not tagged as lost,
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* we do not clear RETRANS, believing
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* that retransmission is still in flight.
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*/
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if (sacked & TCPCB_LOST) {
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TCP_SKB_CB(skb)->sacked &= ~(TCPCB_LOST|TCPCB_SACKED_RETRANS);
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tp->lost_out -= tcp_skb_pcount(skb);
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tp->retrans_out -= tcp_skb_pcount(skb);
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/* clear lost hint */
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tp->retransmit_skb_hint = NULL;
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}
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} else {
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if (!(sacked & TCPCB_RETRANS)) {
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/* New sack for not retransmitted frame,
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* which was in hole. It is reordering.
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*/
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if (before(TCP_SKB_CB(skb)->seq,
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tcp_highest_sack_seq(tp)))
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reord = min(fack_count, reord);
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/* SACK enhanced F-RTO (RFC4138; Appendix B) */
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if (!after(TCP_SKB_CB(skb)->end_seq, tp->frto_highmark))
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flag |= FLAG_ONLY_ORIG_SACKED;
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}
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if (sacked & TCPCB_LOST) {
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TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
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tp->lost_out -= tcp_skb_pcount(skb);
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/* clear lost hint */
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tp->retransmit_skb_hint = NULL;
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}
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}
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TCP_SKB_CB(skb)->sacked |= TCPCB_SACKED_ACKED;
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flag |= FLAG_DATA_SACKED;
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tp->sacked_out += tcp_skb_pcount(skb);
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fack_count += tcp_skb_pcount(skb);
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/* Lost marker hint past SACKed? Tweak RFC3517 cnt */
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if (!tcp_is_fack(tp) && (tp->lost_skb_hint != NULL) &&
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before(TCP_SKB_CB(skb)->seq,
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TCP_SKB_CB(tp->lost_skb_hint)->seq))
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tp->lost_cnt_hint += tcp_skb_pcount(skb);
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if (fack_count > tp->fackets_out)
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tp->fackets_out = fack_count;
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if (after(TCP_SKB_CB(skb)->seq, tcp_highest_sack_seq(tp)))
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tp->highest_sack = skb;
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} else {
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if (dup_sack && (sacked&TCPCB_RETRANS))
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reord = min(fack_count, reord);
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fack_count += tcp_skb_pcount(skb);
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}
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/* D-SACK. We can detect redundant retransmission
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* in S|R and plain R frames and clear it.
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* undo_retrans is decreased above, L|R frames
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* are accounted above as well.
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*/
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if (dup_sack &&
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(TCP_SKB_CB(skb)->sacked&TCPCB_SACKED_RETRANS)) {
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TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
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tp->retrans_out -= tcp_skb_pcount(skb);
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tp->retransmit_skb_hint = NULL;
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}
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fack_count += tcp_skb_pcount(skb);
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}
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/* SACK enhanced FRTO (RFC4138, Appendix B): Clearing correct
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