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[TCP]: Create tcp_sacktag_one().
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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>
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Ilpo Järvinen authored and David S. Miller committed Jan 28, 2008
1 parent b7d4815 commit 9e10c47
Showing 1 changed file with 96 additions and 96 deletions.
192 changes: 96 additions & 96 deletions net/ipv4/tcp_input.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1240,6 +1240,99 @@ static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb,
return in_sack;
}

static int tcp_sacktag_one(struct sk_buff *skb, struct tcp_sock *tp,
int *reord, int dup_sack, int fack_count)
{
u8 sacked = TCP_SKB_CB(skb)->sacked;
int flag = 0;

/* Account D-SACK for retransmitted packet. */
if (dup_sack && (sacked & TCPCB_RETRANS)) {
if (after(TCP_SKB_CB(skb)->end_seq, tp->undo_marker))
tp->undo_retrans--;
if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una) &&
(sacked & TCPCB_SACKED_ACKED))
*reord = min(fack_count, *reord);
}

/* Nothing to do; acked frame is about to be dropped (was ACKed). */
if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una))
return flag;

if (!(sacked & TCPCB_SACKED_ACKED)) {
if (sacked & TCPCB_SACKED_RETRANS) {
/* If the segment is not tagged as lost,
* we do not clear RETRANS, believing
* that retransmission is still in flight.
*/
if (sacked & TCPCB_LOST) {
TCP_SKB_CB(skb)->sacked &=
~(TCPCB_LOST|TCPCB_SACKED_RETRANS);
tp->lost_out -= tcp_skb_pcount(skb);
tp->retrans_out -= tcp_skb_pcount(skb);

/* clear lost hint */
tp->retransmit_skb_hint = NULL;
}
} else {
if (!(sacked & TCPCB_RETRANS)) {
/* New sack for not retransmitted frame,
* which was in hole. It is reordering.
*/
if (before(TCP_SKB_CB(skb)->seq,
tcp_highest_sack_seq(tp)))
*reord = min(fack_count, *reord);

/* SACK enhanced F-RTO (RFC4138; Appendix B) */
if (!after(TCP_SKB_CB(skb)->end_seq, tp->frto_highmark))
flag |= FLAG_ONLY_ORIG_SACKED;
}

if (sacked & TCPCB_LOST) {
TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
tp->lost_out -= tcp_skb_pcount(skb);

/* clear lost hint */
tp->retransmit_skb_hint = NULL;
}
}

TCP_SKB_CB(skb)->sacked |= TCPCB_SACKED_ACKED;
flag |= FLAG_DATA_SACKED;
tp->sacked_out += tcp_skb_pcount(skb);

fack_count += tcp_skb_pcount(skb);

/* Lost marker hint past SACKed? Tweak RFC3517 cnt */
if (!tcp_is_fack(tp) && (tp->lost_skb_hint != NULL) &&
before(TCP_SKB_CB(skb)->seq,
TCP_SKB_CB(tp->lost_skb_hint)->seq))
tp->lost_cnt_hint += tcp_skb_pcount(skb);

if (fack_count > tp->fackets_out)
tp->fackets_out = fack_count;

if (after(TCP_SKB_CB(skb)->seq, tcp_highest_sack_seq(tp)))
tp->highest_sack = skb;

} else {
if (dup_sack && (sacked & TCPCB_RETRANS))
*reord = min(fack_count, *reord);
}

/* D-SACK. We can detect redundant retransmission in S|R and plain R
* frames and clear it. undo_retrans is decreased above, L|R frames
* are accounted above as well.
*/
if (dup_sack && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS)) {
TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
tp->retrans_out -= tcp_skb_pcount(skb);
tp->retransmit_skb_hint = NULL;
}

return flag;
}

static int
tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_una)
{
Expand Down Expand Up @@ -1375,7 +1468,6 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_

tcp_for_write_queue_from(skb, sk) {
int in_sack = 0;
u8 sacked;

if (skb == tcp_send_head(sk))
break;
Expand Down Expand Up @@ -1413,102 +1505,10 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
if (unlikely(in_sack < 0))
break;

if (!in_sack) {
fack_count += tcp_skb_pcount(skb);
continue;
}

sacked = TCP_SKB_CB(skb)->sacked;

/* Account D-SACK for retransmitted packet. */
if (dup_sack && (sacked & TCPCB_RETRANS)) {
if (after(TCP_SKB_CB(skb)->end_seq, tp->undo_marker))
tp->undo_retrans--;
if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una) &&
(sacked & TCPCB_SACKED_ACKED))
reord = min(fack_count, reord);
}


/* Nothing to do; acked frame is about to be dropped (was ACKed). */
if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una)) {
fack_count += tcp_skb_pcount(skb);
continue;
}

if (!(sacked&TCPCB_SACKED_ACKED)) {
if (sacked & TCPCB_SACKED_RETRANS) {
/* If the segment is not tagged as lost,
* we do not clear RETRANS, believing
* that retransmission is still in flight.
*/
if (sacked & TCPCB_LOST) {
TCP_SKB_CB(skb)->sacked &= ~(TCPCB_LOST|TCPCB_SACKED_RETRANS);
tp->lost_out -= tcp_skb_pcount(skb);
tp->retrans_out -= tcp_skb_pcount(skb);

/* clear lost hint */
tp->retransmit_skb_hint = NULL;
}
} else {
if (!(sacked & TCPCB_RETRANS)) {
/* New sack for not retransmitted frame,
* which was in hole. It is reordering.
*/
if (before(TCP_SKB_CB(skb)->seq,
tcp_highest_sack_seq(tp)))
reord = min(fack_count, reord);

/* SACK enhanced F-RTO (RFC4138; Appendix B) */
if (!after(TCP_SKB_CB(skb)->end_seq, tp->frto_highmark))
flag |= FLAG_ONLY_ORIG_SACKED;
}

if (sacked & TCPCB_LOST) {
TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
tp->lost_out -= tcp_skb_pcount(skb);

/* clear lost hint */
tp->retransmit_skb_hint = NULL;
}
}

TCP_SKB_CB(skb)->sacked |= TCPCB_SACKED_ACKED;
flag |= FLAG_DATA_SACKED;
tp->sacked_out += tcp_skb_pcount(skb);

fack_count += tcp_skb_pcount(skb);

/* Lost marker hint past SACKed? Tweak RFC3517 cnt */
if (!tcp_is_fack(tp) && (tp->lost_skb_hint != NULL) &&
before(TCP_SKB_CB(skb)->seq,
TCP_SKB_CB(tp->lost_skb_hint)->seq))
tp->lost_cnt_hint += tcp_skb_pcount(skb);

if (fack_count > tp->fackets_out)
tp->fackets_out = fack_count;
if (in_sack)
flag |= tcp_sacktag_one(skb, tp, &reord, dup_sack, fack_count);

if (after(TCP_SKB_CB(skb)->seq, tcp_highest_sack_seq(tp)))
tp->highest_sack = skb;

} else {
if (dup_sack && (sacked&TCPCB_RETRANS))
reord = min(fack_count, reord);

fack_count += tcp_skb_pcount(skb);
}

/* D-SACK. We can detect redundant retransmission
* in S|R and plain R frames and clear it.
* undo_retrans is decreased above, L|R frames
* are accounted above as well.
*/
if (dup_sack &&
(TCP_SKB_CB(skb)->sacked&TCPCB_SACKED_RETRANS)) {
TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
tp->retrans_out -= tcp_skb_pcount(skb);
tp->retransmit_skb_hint = NULL;
}
fack_count += tcp_skb_pcount(skb);
}

/* SACK enhanced FRTO (RFC4138, Appendix B): Clearing correct
Expand Down

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