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Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r--net/ipv4/tcp_input.c221
1 files changed, 118 insertions, 103 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index c26076fb890e..1a14191687ac 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -50,9 +50,9 @@
* Andi Kleen: Make sure we never ack data there is not
* enough room for. Also make this condition
* a fatal error if it might still happen.
- * Andi Kleen: Add tcp_measure_rcv_mss to make
+ * Andi Kleen: Add tcp_measure_rcv_mss to make
* connections with MSS<min(MTU,ann. MSS)
- * work without delayed acks.
+ * work without delayed acks.
* Andi Kleen: Process packets with PSH set in the
* fast path.
* J Hadi Salim: ECN support
@@ -112,17 +112,17 @@ int sysctl_tcp_abc __read_mostly;
#define TCP_REMNANT (TCP_FLAG_FIN|TCP_FLAG_URG|TCP_FLAG_SYN|TCP_FLAG_PSH)
-/* Adapt the MSS value used to make delayed ack decision to the
+/* Adapt the MSS value used to make delayed ack decision to the
* real world.
- */
+ */
static void tcp_measure_rcv_mss(struct sock *sk,
const struct sk_buff *skb)
{
struct inet_connection_sock *icsk = inet_csk(sk);
- const unsigned int lss = icsk->icsk_ack.last_seg_size;
+ const unsigned int lss = icsk->icsk_ack.last_seg_size;
unsigned int len;
- icsk->icsk_ack.last_seg_size = 0;
+ icsk->icsk_ack.last_seg_size = 0;
/* skb->len may jitter because of SACKs, even if peer
* sends good full-sized frames.
@@ -440,15 +440,15 @@ void tcp_rcv_space_adjust(struct sock *sk)
struct tcp_sock *tp = tcp_sk(sk);
int time;
int space;
-
+
if (tp->rcvq_space.time == 0)
goto new_measure;
-
+
time = tcp_time_stamp - tp->rcvq_space.time;
if (time < (tp->rcv_rtt_est.rtt >> 3) ||
tp->rcv_rtt_est.rtt == 0)
return;
-
+
space = 2 * (tp->copied_seq - tp->rcvq_space.seq);
space = max(tp->rcvq_space.space, space);
@@ -483,7 +483,7 @@ void tcp_rcv_space_adjust(struct sock *sk)
}
}
}
-
+
new_measure:
tp->rcvq_space.seq = tp->copied_seq;
tp->rcvq_space.time = tcp_time_stamp;
@@ -509,7 +509,7 @@ static void tcp_event_data_recv(struct sock *sk, struct tcp_sock *tp, struct sk_
tcp_measure_rcv_mss(sk, skb);
tcp_rcv_rtt_measure(tp);
-
+
now = tcp_time_stamp;
if (!icsk->icsk_ack.ato) {
@@ -561,7 +561,7 @@ static void tcp_rtt_estimator(struct sock *sk, const __u32 mrtt)
/* The following amusing code comes from Jacobson's
* article in SIGCOMM '88. Note that rtt and mdev
* are scaled versions of rtt and mean deviation.
- * This is designed to be as fast as possible
+ * This is designed to be as fast as possible
* m stands for "measurement".
*
* On a 1990 paper the rto value is changed to:
@@ -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.
@@ -1234,8 +1249,8 @@ void tcp_enter_frto(struct sock *sk)
tp->frto_counter = 1;
if (icsk->icsk_ca_state <= TCP_CA_Disorder ||
- tp->snd_una == tp->high_seq ||
- (icsk->icsk_ca_state == TCP_CA_Loss && !icsk->icsk_retransmits)) {
+ tp->snd_una == tp->high_seq ||
+ (icsk->icsk_ca_state == TCP_CA_Loss && !icsk->icsk_retransmits)) {
tp->prior_ssthresh = tcp_current_ssthresh(sk);
tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk);
tcp_ca_event(sk, CA_EVENT_FRTO);
@@ -1954,11 +1969,11 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
* 1. Reno does not count dupacks (sacked_out) automatically. */
if (!tp->packets_out)
tp->sacked_out = 0;
- /* 2. SACK counts snd_fack in packets inaccurately. */
+ /* 2. SACK counts snd_fack in packets inaccurately. */
if (tp->sacked_out == 0)
tp->fackets_out = 0;
- /* Now state machine starts.
+ /* Now state machine starts.
* A. ECE, hence prohibit cwnd undoing, the reduction is required. */
if (flag&FLAG_ECE)
tp->prior_ssthresh = 0;
@@ -2188,7 +2203,7 @@ static int tcp_tso_acked(struct sock *sk, struct sk_buff *skb,
__u32 now, __s32 *seq_rtt)
{
struct tcp_sock *tp = tcp_sk(sk);
- struct tcp_skb_cb *scb = TCP_SKB_CB(skb);
+ struct tcp_skb_cb *scb = TCP_SKB_CB(skb);
__u32 seq = tp->snd_una;
__u32 packets_acked;
int acked = 0;
@@ -2264,7 +2279,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
while ((skb = skb_peek(&sk->sk_write_queue)) &&
skb != sk->sk_send_head) {
- struct tcp_skb_cb *scb = TCP_SKB_CB(skb);
+ struct tcp_skb_cb *scb = TCP_SKB_CB(skb);
__u8 sacked = scb->sacked;
/* If our packet is before the ack sequence we can
@@ -2455,9 +2470,9 @@ static int tcp_ack_update_window(struct sock *sk, struct tcp_sock *tp,
static void tcp_process_frto(struct sock *sk, u32 prior_snd_una)
{
struct tcp_sock *tp = tcp_sk(sk);
-
+
tcp_sync_left_out(tp);
-
+
if (tp->snd_una == prior_snd_una ||
!before(tp->snd_una, tp->frto_highmark)) {
/* RTO was caused by loss, start retransmitting in
@@ -2612,7 +2627,7 @@ void tcp_parse_options(struct sk_buff *skb, struct tcp_options_received *opt_rx,
opt_rx->saw_tstamp = 0;
while(length>0) {
- int opcode=*ptr++;
+ int opcode=*ptr++;
int opsize;
switch (opcode) {
@@ -2627,7 +2642,7 @@ void tcp_parse_options(struct sk_buff *skb, struct tcp_options_received *opt_rx,
return;
if (opsize > length)
return; /* don't parse partial options */
- switch(opcode) {
+ switch(opcode) {
case TCPOPT_MSS:
if(opsize==TCPOLEN_MSS && th->syn && !estab) {
u16 in_mss = ntohs(get_unaligned((__be16 *)ptr));
@@ -2686,10 +2701,10 @@ void tcp_parse_options(struct sk_buff *skb, struct tcp_options_received *opt_rx,
*/
break;
#endif
- };
- ptr+=opsize-2;
- length-=opsize;
- };
+ };
+ ptr+=opsize-2;
+ length-=opsize;
+ };
}
}
@@ -3248,7 +3263,7 @@ drop:
TCP_SKB_CB(skb)->end_seq);
tcp_dsack_set(tp, TCP_SKB_CB(skb)->seq, tp->rcv_nxt);
-
+
/* If window is closed, drop tail of packet. But after
* remembering D-SACK for its head made in previous line.
*/
@@ -3327,7 +3342,7 @@ drop:
}
}
__skb_insert(skb, skb1, skb1->next, &tp->out_of_order_queue);
-
+
/* And clean segments covered by new one as whole. */
while ((skb1 = skb->next) !=
(struct sk_buff*)&tp->out_of_order_queue &&
@@ -3492,7 +3507,7 @@ static void tcp_collapse_ofo_queue(struct sock *sk)
*/
static int tcp_prune_queue(struct sock *sk)
{
- struct tcp_sock *tp = tcp_sk(sk);
+ struct tcp_sock *tp = tcp_sk(sk);
SOCK_DEBUG(sk, "prune_queue: c=%x\n", tp->copied_seq);
@@ -3602,7 +3617,7 @@ static void tcp_new_space(struct sock *sk)
struct tcp_sock *tp = tcp_sk(sk);
if (tcp_should_expand_sndbuf(sk, tp)) {
- int sndmem = max_t(u32, tp->rx_opt.mss_clamp, tp->mss_cache) +
+ int sndmem = max_t(u32, tp->rx_opt.mss_clamp, tp->mss_cache) +
MAX_TCP_HEADER + 16 + sizeof(struct sk_buff),
demanded = max_t(unsigned int, tp->snd_cwnd,
tp->reordering + 1);
@@ -3675,7 +3690,7 @@ static inline void tcp_ack_snd_check(struct sock *sk)
* For 1003.1g we should support a new option TCP_STDURG to permit
* either form (or just set the sysctl tcp_stdurg).
*/
-
+
static void tcp_check_urg(struct sock * sk, struct tcphdr * th)
{
struct tcp_sock *tp = tcp_sk(sk);
@@ -3756,7 +3771,7 @@ static void tcp_urg(struct sock *sk, struct sk_buff *skb, struct tcphdr *th)
u32 ptr = tp->urg_seq - ntohl(th->seq) + (th->doff * 4) -
th->syn;
- /* Is the urgent pointer pointing into this packet? */
+ /* Is the urgent pointer pointing into this packet? */
if (ptr < skb->len) {
u8 tmp;
if (skb_copy_bits(skb, ptr, &tmp, 1))
@@ -3820,7 +3835,7 @@ static int tcp_dma_try_early_copy(struct sock *sk, struct sk_buff *skb, int hlen
int copied_early = 0;
if (tp->ucopy.wakeup)
- return 0;
+ return 0;
if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
tp->ucopy.dma_chan = get_softnet_dma();
@@ -3856,26 +3871,26 @@ out:
#endif /* CONFIG_NET_DMA */
/*
- * TCP receive function for the ESTABLISHED state.
+ * TCP receive function for the ESTABLISHED state.
*
- * It is split into a fast path and a slow path. The fast path is
+ * It is split into a fast path and a slow path. The fast path is
* disabled when:
* - A zero window was announced from us - zero window probing
- * is only handled properly in the slow path.
+ * is only handled properly in the slow path.
* - Out of order segments arrived.
* - Urgent data is expected.
* - There is no buffer space left
* - Unexpected TCP flags/window values/header lengths are received
- * (detected by checking the TCP header against pred_flags)
+ * (detected by checking the TCP header against pred_flags)
* - Data is sent in both directions. Fast path only supports pure senders
* or pure receivers (this means either the sequence number or the ack
* value must stay constant)
* - Unexpected TCP option.
*
- * When these conditions are not satisfied it drops into a standard
+ * When these conditions are not satisfied it drops into a standard
* receive procedure patterned after RFC793 to handle all cases.
* The first three cases are guaranteed by proper pred_flags setting,
- * the rest is checked inline. Fast processing is turned on in
+ * the rest is checked inline. Fast processing is turned on in
* tcp_data_queue when everything is OK.
*/
int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
@@ -3885,15 +3900,15 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
/*
* Header prediction.
- * The code loosely follows the one in the famous
+ * The code loosely follows the one in the famous
* "30 instruction TCP receive" Van Jacobson mail.
- *
- * Van's trick is to deposit buffers into socket queue
+ *
+ * Van's trick is to deposit buffers into socket queue
* on a device interrupt, to call tcp_recv function
* on the receive process context and checksum and copy
* the buffer to user space. smart...
*
- * Our current scheme is not silly either but we take the
+ * Our current scheme is not silly either but we take the
* extra cost of the net_bh soft interrupt processing...
* We do checksum and copy also but from device to kernel.
*/
@@ -3904,7 +3919,7 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
* if header_prediction is to be made
* 'S' will always be tp->tcp_header_len >> 2
* '?' will be 0 for the fast path, otherwise pred_flags is 0 to
- * turn it off (when there are holes in the receive
+ * turn it off (when there are holes in the receive
* space for instance)
* PSH flag is ignored.
*/
@@ -3928,7 +3943,7 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
goto slow_path;
tp->rx_opt.saw_tstamp = 1;
- ++ptr;
+ ++ptr;
tp->rx_opt.rcv_tsval = ntohl(*ptr);
++ptr;
tp->rx_opt.rcv_tsecr = ntohl(*ptr);
@@ -3960,7 +3975,7 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
* on entry.
*/
tcp_ack(sk, skb, 0);
- __kfree_skb(skb);
+ __kfree_skb(skb);
tcp_data_snd_check(sk, tp);
return 0;
} else { /* Header too small */
@@ -4378,11 +4393,11 @@ reset_and_undo:
/*
* This function implements the receiving procedure of RFC 793 for
- * all states except ESTABLISHED and TIME_WAIT.
+ * all states except ESTABLISHED and TIME_WAIT.
* It's called from both tcp_v4_rcv and tcp_v6_rcv and should be
* address independent.
*/
-
+
int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
struct tcphdr *th, unsigned len)
{
@@ -4407,19 +4422,19 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
if (icsk->icsk_af_ops->conn_request(sk, skb) < 0)
return 1;
- /* Now we have several options: In theory there is
- * nothing else in the frame. KA9Q has an option to
+ /* Now we have several options: In theory there is
+ * nothing else in the frame. KA9Q has an option to
* send data with the syn, BSD accepts data with the
- * syn up to the [to be] advertised window and
- * Solaris 2.1 gives you a protocol error. For now
- * we just ignore it, that fits the spec precisely
+ * syn up to the [to be] advertised window and
+ * Solaris 2.1 gives you a protocol error. For now
+ * we just ignore it, that fits the spec precisely
* and avoids incompatibilities. It would be nice in
* future to drop through and process the data.
*
- * Now that TTCP is starting to be used we ought to
+ * Now that TTCP is starting to be used we ought to
* queue this data.
* But, this leaves one open to an easy denial of
- * service attack, and SYN cookies can't defend
+ * service attack, and SYN cookies can't defend
* against this problem. So, we drop the data
* in the interest of security over speed unless
* it's still in use.
@@ -4609,7 +4624,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
case TCP_FIN_WAIT1:
case TCP_FIN_WAIT2:
/* RFC 793 says to queue data in these states,
- * RFC 1122 says we MUST send a reset.
+ * RFC 1122 says we MUST send a reset.
* BSD 4.4 also does reset.
*/
if (sk->sk_shutdown & RCV_SHUTDOWN) {
@@ -4621,7 +4636,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
}
}
/* Fall through */
- case TCP_ESTABLISHED:
+ case TCP_ESTABLISHED:
tcp_data_queue(sk, skb);
queued = 1;
break;
@@ -4633,7 +4648,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
tcp_ack_snd_check(sk);
}
- if (!queued) {
+ if (!queued) {
discard:
__kfree_skb(skb);
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-15 19:54:48 +0300