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Commit fd6dad61 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
Browse files

[TCP]: Earlier SACK block verification & simplify access to them 



Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9e10c47c

include/linux/tcp.h

+1 −1
Original line number Diff line number Diff line
@@ -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

net/ipv4/tcp_input.c

+51 −34
Original line number Diff line number Diff line
@@ -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);