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Message-Id: <11921053184007-git-send-email-ilpo.jarvinen@helsinki.fi>
Date: Thu, 11 Oct 2007 15:21:56 +0300
From: "Ilpo Järvinen" <ilpo.jarvinen@...sinki.fi>
To: David Miller <davem@...emloft.net>
Cc: netdev@...r.kernel.org, TAKANO Ryousei <takano@...-inc.co.jp>,
--cc@...helsinki.fi
Subject: [PATCH 4/6] [TCP]: Earlier SACK block verification & simplify access to them
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...sinki.fi>
---
include/linux/tcp.h | 2 +-
net/ipv4/tcp_input.c | 75 ++++++++++++++++++++++++++++++-------------------
2 files changed, 47 insertions(+), 30 deletions(-)
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 0ec6bb6..3e412f2 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -330,7 +330,7 @@ struct tcp_sock {
struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
- struct tcp_sack_block_wire recv_sack_cache[4];
+ struct tcp_sack_block recv_sack_cache[4];
struct sk_buff *highest_sack; /* highest skb with SACK received
* (validity guaranteed only if
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 39d6a6a..c260642 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1350,9 +1350,11 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
struct tcp_sock *tp = tcp_sk(sk);
unsigned char *ptr = (skb_transport_header(ack_skb) +
TCP_SKB_CB(ack_skb)->sacked);
- struct tcp_sack_block_wire *sp = (struct tcp_sack_block_wire *)(ptr+2);
+ struct tcp_sack_block_wire *sp_wire = (struct tcp_sack_block_wire *)(ptr+2);
+ struct tcp_sack_block sp[4];
struct sk_buff *cached_skb;
int num_sacks = (ptr[1] - TCPOLEN_SACK_BASE)>>3;
+ int used_sacks;
struct tcp_sacktag_state state;
int found_dup_sack;
int cached_fack_count;
@@ -1367,7 +1369,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
tp->highest_sack = tcp_write_queue_head(sk);
}
- found_dup_sack = tcp_check_dsack(tp, ack_skb, sp, num_sacks, prior_snd_una);
+ found_dup_sack = tcp_check_dsack(tp, ack_skb, sp_wire, num_sacks, prior_snd_una);
if (found_dup_sack)
state.flag |= FLAG_DSACKING_ACK;
@@ -1378,14 +1380,46 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
if (before(TCP_SKB_CB(ack_skb)->ack_seq, prior_snd_una - tp->max_window))
return 0;
+ used_sacks = 0;
+ for (i = 0; i < num_sacks; i++) {
+ int dup_sack = !i && found_dup_sack;
+
+ sp[used_sacks].start_seq = ntohl(get_unaligned(&sp_wire[i].start_seq));
+ sp[used_sacks].end_seq = ntohl(get_unaligned(&sp_wire[i].end_seq));
+
+ if (!tcp_is_sackblock_valid(tp, dup_sack,
+ sp[used_sacks].start_seq,
+ sp[used_sacks].end_seq)) {
+ if (dup_sack) {
+ if (!tp->undo_marker)
+ NET_INC_STATS_BH(LINUX_MIB_TCPDSACKIGNOREDNOUNDO);
+ else
+ NET_INC_STATS_BH(LINUX_MIB_TCPDSACKIGNOREDOLD);
+ } else {
+ /* Don't count olds caused by ACK reordering */
+ if ((TCP_SKB_CB(ack_skb)->ack_seq != tp->snd_una) &&
+ !after(sp[used_sacks].end_seq, tp->snd_una))
+ continue;
+ NET_INC_STATS_BH(LINUX_MIB_TCPSACKDISCARD);
+ }
+ continue;
+ }
+
+ /* Ignore very old stuff early */
+ if (!after(sp[used_sacks].end_seq, prior_snd_una))
+ continue;
+
+ used_sacks++;
+ }
+
/* SACK fastpath:
* if the only SACK change is the increase of the end_seq of
* the first block then only apply that SACK block
* and use retrans queue hinting otherwise slowpath */
force_one_sack = 1;
- for (i = 0; i < num_sacks; i++) {
- __be32 start_seq = sp[i].start_seq;
- __be32 end_seq = sp[i].end_seq;
+ for (i = 0; i < used_sacks; i++) {
+ u32 start_seq = sp[i].start_seq;
+ u32 end_seq = sp[i].end_seq;
if (i == 0) {
if (tp->recv_sack_cache[i].start_seq != start_seq)
@@ -1406,17 +1440,16 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
state.first_sack_index = 0;
if (force_one_sack)
- num_sacks = 1;
+ used_sacks = 1;
else {
int j;
tp->fastpath_skb_hint = NULL;
/* order SACK blocks to allow in order walk of the retrans queue */
- for (i = num_sacks-1; i > 0; i--) {
+ for (i = used_sacks-1; i > 0; i--) {
for (j = 0; j < i; j++){
- if (after(ntohl(sp[j].start_seq),
- ntohl(sp[j+1].start_seq))){
- struct tcp_sack_block_wire tmp;
+ if (after(sp[j].start_seq, sp[j+1].start_seq)) {
+ struct tcp_sack_block tmp;
tmp = sp[j];
sp[j] = sp[j+1];
@@ -1443,29 +1476,13 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
state.prior_fackets = tp->fackets_out;
state.highest_sack_end_seq = 0;
- for (i=0; i<num_sacks; i++, sp++) {
+ for (i=0; i< used_sacks; i++) {
struct sk_buff *skb;
- __u32 start_seq = ntohl(sp->start_seq);
- __u32 end_seq = ntohl(sp->end_seq);
+ u32 start_seq = sp[i].start_seq;
+ u32 end_seq = sp[i].end_seq;
int fack_count;
int dup_sack = (found_dup_sack && (i == state.first_sack_index));
- if (!tcp_is_sackblock_valid(tp, dup_sack, start_seq, end_seq)) {
- if (dup_sack) {
- if (!tp->undo_marker)
- NET_INC_STATS_BH(LINUX_MIB_TCPDSACKIGNOREDNOUNDO);
- else
- NET_INC_STATS_BH(LINUX_MIB_TCPDSACKIGNOREDOLD);
- } else {
- /* Don't count olds caused by ACK reordering */
- if ((TCP_SKB_CB(ack_skb)->ack_seq != tp->snd_una) &&
- !after(end_seq, tp->snd_una))
- continue;
- NET_INC_STATS_BH(LINUX_MIB_TCPSACKDISCARD);
- }
- continue;
- }
-
skb = cached_skb;
fack_count = cached_fack_count;
--
1.5.0.6
-
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