diff options
Diffstat (limited to 'net/ipv4/tcp_input.c')
| -rw-r--r-- | net/ipv4/tcp_input.c | 105 |
1 files changed, 60 insertions, 45 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index c26076fb890..c6109895bb5 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -936,28 +936,58 @@ 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 = ack_skb->h.raw + TCP_SKB_CB(ack_skb)->sacked; struct tcp_sack_block_wire *sp = (struct tcp_sack_block_wire *)(ptr+2); + struct sk_buff *cached_skb; int num_sacks = (ptr[1] - TCPOLEN_SACK_BASE)>>3; int reord = tp->packets_out; int prior_fackets; u32 lost_retrans = 0; int flag = 0; int dup_sack = 0; + int cached_fack_count; int i; + int first_sack_index; if (!tp->sacked_out) tp->fackets_out = 0; prior_fackets = tp->fackets_out; + /* Check for D-SACK. */ + if (before(ntohl(sp[0].start_seq), TCP_SKB_CB(ack_skb)->ack_seq)) { + dup_sack = 1; + tp->rx_opt.sack_ok |= 4; + NET_INC_STATS_BH(LINUX_MIB_TCPDSACKRECV); + } else if (num_sacks > 1 && + !after(ntohl(sp[0].end_seq), ntohl(sp[1].end_seq)) && + !before(ntohl(sp[0].start_seq), ntohl(sp[1].start_seq))) { + dup_sack = 1; + tp->rx_opt.sack_ok |= 4; + NET_INC_STATS_BH(LINUX_MIB_TCPDSACKOFORECV); + } + + /* D-SACK for already forgotten data... + * Do dumb counting. */ + if (dup_sack && + !after(ntohl(sp[0].end_seq), prior_snd_una) && + after(ntohl(sp[0].end_seq), tp->undo_marker)) + tp->undo_retrans--; + + /* Eliminate too old ACKs, but take into + * account more or less fresh ones, they can + * contain valid SACK info. + */ + if (before(TCP_SKB_CB(ack_skb)->ack_seq, prior_snd_una - tp->max_window)) + return 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); + for (i = 0; i < num_sacks; i++) { + __be32 start_seq = sp[i].start_seq; + __be32 end_seq = sp[i].end_seq; - if (i == 0){ + if (i == 0) { if (tp->recv_sack_cache[i].start_seq != start_seq) flag = 0; } else { @@ -967,39 +997,14 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ } 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) { - u32 ack = TCP_SKB_CB(ack_skb)->ack_seq; - - if (before(start_seq, ack)) { - dup_sack = 1; - tp->rx_opt.sack_ok |= 4; - NET_INC_STATS_BH(LINUX_MIB_TCPDSACKRECV); - } else if (num_sacks > 1 && - !after(end_seq, ntohl(sp[1].end_seq)) && - !before(start_seq, ntohl(sp[1].start_seq))) { - dup_sack = 1; - tp->rx_opt.sack_ok |= 4; - NET_INC_STATS_BH(LINUX_MIB_TCPDSACKOFORECV); - } - - /* D-SACK for already forgotten data... - * Do dumb counting. */ - if (dup_sack && - !after(end_seq, prior_snd_una) && - after(end_seq, tp->undo_marker)) - tp->undo_retrans--; - - /* Eliminate too old ACKs, but take into - * account more or less fresh ones, they can - * contain valid SACK info. - */ - if (before(ack, prior_snd_una - tp->max_window)) - return 0; - } + } + /* Clear the rest of the cache sack blocks so they won't match mistakenly. */ + for (; i < ARRAY_SIZE(tp->recv_sack_cache); i++) { + tp->recv_sack_cache[i].start_seq = 0; + tp->recv_sack_cache[i].end_seq = 0; } + first_sack_index = 0; if (flag) num_sacks = 1; else { @@ -1016,6 +1021,10 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ tmp = sp[j]; sp[j] = sp[j+1]; sp[j+1] = tmp; + + /* Track where the first SACK block goes to */ + if (j == first_sack_index) + first_sack_index = j+1; } } @@ -1025,20 +1034,22 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ /* clear flag as used for different purpose in following code */ flag = 0; + /* Use SACK fastpath hint if valid */ + cached_skb = tp->fastpath_skb_hint; + cached_fack_count = tp->fastpath_cnt_hint; + if (!cached_skb) { + cached_skb = sk->sk_write_queue.next; + cached_fack_count = 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; - } + skb = cached_skb; + fack_count = cached_fack_count; /* Event "B" in the comment above. */ if (after(end_seq, tp->high_seq)) @@ -1048,8 +1059,12 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ int in_sack, pcount; u8 sacked; - tp->fastpath_skb_hint = skb; - tp->fastpath_cnt_hint = fack_count; + cached_skb = skb; + cached_fack_count = fack_count; + if (i == first_sack_index) { + 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. |