From fd6dad616d4fe2f08d690f25ca76b0102158fb3a Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ilpo=20J=C3=A4rvinen?= Date: Thu, 15 Nov 2007 19:49:47 -0800 Subject: [PATCH] [TCP]: Earlier SACK block verification & simplify access to them MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- include/linux/tcp.h | 2 +- net/ipv4/tcp_input.c | 85 ++++++++++++++++++++++++++------------------ 2 files changed, 52 insertions(+), 35 deletions(-) diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 34acee662230..794497c7d755 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 a62e0f90f566..a287747e9dd6 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -1340,9 +1340,11 @@ 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; int reord = tp->packets_out; int flag = 0; int found_dup_sack = 0; @@ -1357,7 +1359,7 @@ 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, + found_dup_sack = tcp_check_dsack(tp, ack_skb, sp_wire, num_sacks, prior_snd_una); if (found_dup_sack) flag |= FLAG_DSACKING_ACK; @@ -1372,14 +1374,49 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ if (!tp->packets_out) goto out; + used_sacks = 0; + first_sack_index = 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); + } + if (i == 0) + first_sack_index = -1; + 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) @@ -1398,19 +1435,17 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ tp->recv_sack_cache[i].end_seq = 0; } - 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]; @@ -1433,32 +1468,14 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ cached_fack_count = 0; } - for (i = 0; i < num_sacks; i++) { + 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 == first_sack_index)); int next_dup = (found_dup_sack && (i+1 == first_sack_index)); - sp++; - - 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; @@ -1489,8 +1506,8 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ /* Due to sorting DSACK may reside within this SACK block! */ if (next_dup) { - u32 dup_start = ntohl(sp->start_seq); - u32 dup_end = ntohl(sp->end_seq); + u32 dup_start = sp[i+1].start_seq; + u32 dup_end = sp[i+1].end_seq; if (before(TCP_SKB_CB(skb)->seq, dup_end)) { in_sack = tcp_match_skb_to_sack(sk, skb, dup_start, dup_end); -- 2.20.1