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yaml
---
r: 13835
b: refs/heads/master
c: 6a438bb
h: refs/heads/master
i:
  13833: 1c361b3
  13831: dbe5414
v: v3
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Stephen Hemminger authored and David S. Miller committed Nov 11, 2005
1 parent c239d17 commit cd074ad
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Showing 6 changed files with 203 additions and 27 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: caa20d9abe810be2ede9612b6c9db6ce7d6edf80
refs/heads/master: 6a438bbe68c7013a42d9c5aee5a40d7dafdbe6ec
15 changes: 15 additions & 0 deletions trunk/include/linux/tcp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -307,6 +307,21 @@ 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 recv_sack_cache[4];

/* from STCP, retrans queue hinting */
struct sk_buff* lost_skb_hint;

struct sk_buff *scoreboard_skb_hint;
struct sk_buff *retransmit_skb_hint;
struct sk_buff *forward_skb_hint;
struct sk_buff *fastpath_skb_hint;

int fastpath_cnt_hint;
int lost_cnt_hint;
int retransmit_cnt_hint;
int forward_cnt_hint;

__u16 advmss; /* Advertised MSS */
__u16 prior_ssthresh; /* ssthresh saved at recovery start */
__u32 lost_out; /* Lost packets */
Expand Down
6 changes: 6 additions & 0 deletions trunk/include/net/sock.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1247,6 +1247,12 @@ static inline struct page *sk_stream_alloc_page(struct sock *sk)
(skb != (struct sk_buff *)&(sk)->sk_write_queue); \
skb = skb->next)

/*from STCP for fast SACK Process*/
#define sk_stream_for_retrans_queue_from(skb, sk) \
for (; (skb != (sk)->sk_send_head) && \
(skb != (struct sk_buff *)&(sk)->sk_write_queue); \
skb = skb->next)

/*
* Default write policy as shown to user space via poll/select/SIGIO
*/
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9 changes: 9 additions & 0 deletions trunk/include/net/tcp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1207,6 +1207,15 @@ static inline void tcp_mib_init(void)
TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1);
}

/*from STCP */
static inline void clear_all_retrans_hints(struct tcp_sock *tp){
tp->lost_skb_hint = NULL;
tp->scoreboard_skb_hint = NULL;
tp->retransmit_skb_hint = NULL;
tp->forward_skb_hint = NULL;
tp->fastpath_skb_hint = NULL;
}

/* /proc */
enum tcp_seq_states {
TCP_SEQ_STATE_LISTENING,
Expand Down
144 changes: 129 additions & 15 deletions trunk/net/ipv4/tcp_input.c
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Original file line number Diff line number Diff line change
Expand Up @@ -897,18 +897,32 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
int prior_fackets;
u32 lost_retrans = 0;
int flag = 0;
int dup_sack = 0;
int i;

if (!tp->sacked_out)
tp->fackets_out = 0;
prior_fackets = tp->fackets_out;

for (i=0; i<num_sacks; i++, sp++) {
struct sk_buff *skb;
__u32 start_seq = ntohl(sp->start_seq);
__u32 end_seq = ntohl(sp->end_seq);
int fack_count = 0;
int dup_sack = 0;
/* 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 */
flag = 1;
for (i = 0; i< num_sacks; i++) {
__u32 start_seq = ntohl(sp[i].start_seq);
__u32 end_seq = ntohl(sp[i].end_seq);

if (i == 0){
if (tp->recv_sack_cache[i].start_seq != start_seq)
flag = 0;
} else {
if ((tp->recv_sack_cache[i].start_seq != start_seq) ||
(tp->recv_sack_cache[i].end_seq != end_seq))
flag = 0;
}
tp->recv_sack_cache[i].start_seq = start_seq;
tp->recv_sack_cache[i].end_seq = end_seq;

/* Check for D-SACK. */
if (i == 0) {
Expand Down Expand Up @@ -940,15 +954,58 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
if (before(ack, prior_snd_una - tp->max_window))
return 0;
}
}

if (flag)
num_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 (j = 0; j < i; j++){
if (after(ntohl(sp[j].start_seq),
ntohl(sp[j+1].start_seq))){
sp[j].start_seq = htonl(tp->recv_sack_cache[j+1].start_seq);
sp[j].end_seq = htonl(tp->recv_sack_cache[j+1].end_seq);
sp[j+1].start_seq = htonl(tp->recv_sack_cache[j].start_seq);
sp[j+1].end_seq = htonl(tp->recv_sack_cache[j].end_seq);
}

}
}
}

/* clear flag as used for different purpose in following code */
flag = 0;

for (i=0; i<num_sacks; i++, sp++) {
struct sk_buff *skb;
__u32 start_seq = ntohl(sp->start_seq);
__u32 end_seq = ntohl(sp->end_seq);
int fack_count;

/* Use SACK fastpath hint if valid */
if (tp->fastpath_skb_hint) {
skb = tp->fastpath_skb_hint;
fack_count = tp->fastpath_cnt_hint;
} else {
skb = sk->sk_write_queue.next;
fack_count = 0;
}

/* Event "B" in the comment above. */
if (after(end_seq, tp->high_seq))
flag |= FLAG_DATA_LOST;

sk_stream_for_retrans_queue(skb, sk) {
sk_stream_for_retrans_queue_from(skb, sk) {
int in_sack, pcount;
u8 sacked;

tp->fastpath_skb_hint = skb;
tp->fastpath_cnt_hint = fack_count;

/* The retransmission queue is always in order, so
* we can short-circuit the walk early.
*/
Expand Down Expand Up @@ -1023,6 +1080,9 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
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 {
/* New sack for not retransmitted frame,
Expand All @@ -1035,6 +1095,9 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
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;
}
}

Expand All @@ -1058,6 +1121,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
(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;
}
}
}
Expand Down Expand Up @@ -1085,6 +1149,9 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
tp->retrans_out -= tcp_skb_pcount(skb);

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

if (!(TCP_SKB_CB(skb)->sacked&(TCPCB_LOST|TCPCB_SACKED_ACKED))) {
tp->lost_out += tcp_skb_pcount(skb);
TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
Expand Down Expand Up @@ -1192,6 +1259,8 @@ static void tcp_enter_frto_loss(struct sock *sk)
tcp_set_ca_state(sk, TCP_CA_Loss);
tp->high_seq = tp->frto_highmark;
TCP_ECN_queue_cwr(tp);

clear_all_retrans_hints(tp);
}

void tcp_clear_retrans(struct tcp_sock *tp)
Expand Down Expand Up @@ -1258,6 +1327,8 @@ void tcp_enter_loss(struct sock *sk, int how)
tcp_set_ca_state(sk, TCP_CA_Loss);
tp->high_seq = tp->snd_nxt;
TCP_ECN_queue_cwr(tp);

clear_all_retrans_hints(tp);
}

static int tcp_check_sack_reneging(struct sock *sk)
Expand Down Expand Up @@ -1482,17 +1553,37 @@ static void tcp_mark_head_lost(struct sock *sk, struct tcp_sock *tp,
int packets, u32 high_seq)
{
struct sk_buff *skb;
int cnt = packets;
int cnt;

BUG_TRAP(cnt <= tp->packets_out);
BUG_TRAP(packets <= tp->packets_out);
if (tp->lost_skb_hint) {
skb = tp->lost_skb_hint;
cnt = tp->lost_cnt_hint;
} else {
skb = sk->sk_write_queue.next;
cnt = 0;
}

sk_stream_for_retrans_queue(skb, sk) {
cnt -= tcp_skb_pcount(skb);
if (cnt < 0 || after(TCP_SKB_CB(skb)->end_seq, high_seq))
sk_stream_for_retrans_queue_from(skb, sk) {
/* TODO: do this better */
/* this is not the most efficient way to do this... */
tp->lost_skb_hint = skb;
tp->lost_cnt_hint = cnt;
cnt += tcp_skb_pcount(skb);
if (cnt > packets || after(TCP_SKB_CB(skb)->end_seq, high_seq))
break;
if (!(TCP_SKB_CB(skb)->sacked&TCPCB_TAGBITS)) {
TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
tp->lost_out += tcp_skb_pcount(skb);

/* clear xmit_retransmit_queue hints
* if this is beyond hint */
if(tp->retransmit_skb_hint != NULL &&
before(TCP_SKB_CB(skb)->seq,
TCP_SKB_CB(tp->retransmit_skb_hint)->seq)) {

tp->retransmit_skb_hint = NULL;
}
}
}
tcp_sync_left_out(tp);
Expand All @@ -1519,13 +1610,28 @@ static void tcp_update_scoreboard(struct sock *sk, struct tcp_sock *tp)
if (tcp_head_timedout(sk, tp)) {
struct sk_buff *skb;

sk_stream_for_retrans_queue(skb, sk) {
if (tcp_skb_timedout(sk, skb) &&
!(TCP_SKB_CB(skb)->sacked&TCPCB_TAGBITS)) {
skb = tp->scoreboard_skb_hint ? tp->scoreboard_skb_hint
: sk->sk_write_queue.next;

sk_stream_for_retrans_queue_from(skb, sk) {
if (!tcp_skb_timedout(sk, skb))
break;

if (!(TCP_SKB_CB(skb)->sacked&TCPCB_TAGBITS)) {
TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
tp->lost_out += tcp_skb_pcount(skb);

/* clear xmit_retrans hint */
if (tp->retransmit_skb_hint &&
before(TCP_SKB_CB(skb)->seq,
TCP_SKB_CB(tp->retransmit_skb_hint)->seq))

tp->retransmit_skb_hint = NULL;
}
}

tp->scoreboard_skb_hint = skb;

tcp_sync_left_out(tp);
}
}
Expand Down Expand Up @@ -1605,6 +1711,10 @@ static void tcp_undo_cwr(struct sock *sk, const int undo)
}
tcp_moderate_cwnd(tp);
tp->snd_cwnd_stamp = tcp_time_stamp;

/* There is something screwy going on with the retrans hints after
an undo */
clear_all_retrans_hints(tp);
}

static inline int tcp_may_undo(struct tcp_sock *tp)
Expand Down Expand Up @@ -1688,6 +1798,9 @@ static int tcp_try_undo_loss(struct sock *sk, struct tcp_sock *tp)
sk_stream_for_retrans_queue(skb, sk) {
TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
}

clear_all_retrans_hints(tp);

DBGUNDO(sk, tp, "partial loss");
tp->lost_out = 0;
tp->left_out = tp->sacked_out;
Expand Down Expand Up @@ -2117,6 +2230,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
tcp_packets_out_dec(tp, skb);
__skb_unlink(skb, &sk->sk_write_queue);
sk_stream_free_skb(sk, skb);
clear_all_retrans_hints(tp);
}

if (acked&FLAG_ACKED) {
Expand Down
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