It is maintained only in during slowpath of tcp_ack(). In most
cases this seqno is available in the last ACK but there is no
guarantee for that. The new fast recovery loss marking algorithm
needs this as entry point.
Signed-off-by: Ilpo Järvinen <[EMAIL PROTECTED]>
---
Now rebased these two patches against the latest net-2.6.22 (no additional
patches are needed as DaveM included RB-tree there).
include/linux/tcp.h | 2 ++
net/ipv4/tcp_input.c | 12 ++++++++++++
net/ipv4/tcp_minisocks.c | 1 +
3 files changed, 15 insertions(+), 0 deletions(-)
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index b73687a..807fc96 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -320,6 +320,8 @@ #endif
struct tcp_sack_block_wire recv_sack_cache[4];
+ u32 highest_sack; /* Start seq of globally highest revd SACK
(valid only in slowpath) */
+
/* from STCP, retrans queue hinting */
struct sk_buff* lost_skb_hint;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 22d0bb0..d738f8e 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1188,6 +1188,10 @@ tcp_sacktag_write_queue(struct sock *sk,
if (fack_count > tp->fackets_out)
tp->fackets_out = fack_count;
+
+ if (after(TCP_SKB_CB(skb)->seq,
+ tp->highest_sack))
+ tp->highest_sack = TCP_SKB_CB(skb)->seq;
} else {
if (dup_sack && (sacked&TCPCB_RETRANS))
reord = min(fack_count, reord);
@@ -2762,10 +2766,18 @@ static int tcp_ack(struct sock *sk, stru
else
NET_INC_STATS_BH(LINUX_MIB_TCPPUREACKS);
+ /* RFC: Transition from fast to slow path, is this a correct
+ * way to detect it?
+ */
+ if (tp->pred_flags)
+ tp->highest_sack = tp->snd_una;
+
flag |= tcp_ack_update_window(sk, tp, skb, ack, ack_seq);
if (TCP_SKB_CB(skb)->sacked)
flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una);
+ else if (before(tp->highest_sack, tp->snd_una))
+ tp->highest_sack = tp->snd_una;
if (TCP_ECN_rcv_ecn_echo(tp, skb->h.th))
flag |= FLAG_ECE;
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 0a57c36..68d0000 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -389,6 +389,7 @@ struct sock *tcp_create_openreq_child(st
newtp->pred_flags = 0;
newtp->rcv_wup = newtp->copied_seq = newtp->rcv_nxt =
treq->rcv_isn + 1;
newtp->snd_sml = newtp->snd_una = newtp->snd_nxt =
treq->snt_isn + 1;
+ newtp->highest_sack = treq->snt_isn + 1;
tcp_prequeue_init(newtp);
--
1.4.2
