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Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r--net/ipv4/tcp_input.c597
1 files changed, 266 insertions, 331 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 887585045b27..dabbf1d392fb 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -76,25 +76,10 @@
#include <linux/ipsec.h>
#include <asm/unaligned.h>
#include <linux/errqueue.h>
+#include <trace/events/tcp.h>
+#include <linux/static_key.h>
-int sysctl_tcp_fack __read_mostly;
-int sysctl_tcp_max_reordering __read_mostly = 300;
-int sysctl_tcp_dsack __read_mostly = 1;
-int sysctl_tcp_app_win __read_mostly = 31;
-int sysctl_tcp_adv_win_scale __read_mostly = 1;
-EXPORT_SYMBOL(sysctl_tcp_adv_win_scale);
-
-/* rfc5961 challenge ack rate limiting */
-int sysctl_tcp_challenge_ack_limit = 1000;
-
-int sysctl_tcp_stdurg __read_mostly;
-int sysctl_tcp_rfc1337 __read_mostly;
int sysctl_tcp_max_orphans __read_mostly = NR_FILE;
-int sysctl_tcp_frto __read_mostly = 2;
-int sysctl_tcp_min_rtt_wlen __read_mostly = 300;
-int sysctl_tcp_moderate_rcvbuf __read_mostly = 1;
-int sysctl_tcp_early_retrans __read_mostly = 3;
-int sysctl_tcp_invalid_ratelimit __read_mostly = HZ/2;
#define FLAG_DATA 0x01 /* Incoming frame contained data. */
#define FLAG_WIN_UPDATE 0x02 /* Incoming ACK was a window update. */
@@ -335,7 +320,7 @@ static void tcp_sndbuf_expand(struct sock *sk)
sndmem *= nr_segs * per_mss;
if (sk->sk_sndbuf < sndmem)
- sk->sk_sndbuf = min(sndmem, sysctl_tcp_wmem[2]);
+ sk->sk_sndbuf = min(sndmem, sock_net(sk)->ipv4.sysctl_tcp_wmem[2]);
}
/* 2. Tuning advertised window (window_clamp, rcv_ssthresh)
@@ -368,8 +353,8 @@ static int __tcp_grow_window(const struct sock *sk, const struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
/* Optimize this! */
- int truesize = tcp_win_from_space(skb->truesize) >> 1;
- int window = tcp_win_from_space(sysctl_tcp_rmem[2]) >> 1;
+ int truesize = tcp_win_from_space(sk, skb->truesize) >> 1;
+ int window = tcp_win_from_space(sk, sock_net(sk)->ipv4.sysctl_tcp_rmem[2]) >> 1;
while (tp->rcv_ssthresh <= window) {
if (truesize <= skb->len)
@@ -394,7 +379,7 @@ static void tcp_grow_window(struct sock *sk, const struct sk_buff *skb)
/* Check #2. Increase window, if skb with such overhead
* will fit to rcvbuf in future.
*/
- if (tcp_win_from_space(skb->truesize) <= skb->len)
+ if (tcp_win_from_space(sk, skb->truesize) <= skb->len)
incr = 2 * tp->advmss;
else
incr = __tcp_grow_window(sk, skb);
@@ -420,11 +405,11 @@ static void tcp_fixup_rcvbuf(struct sock *sk)
/* Dynamic Right Sizing (DRS) has 2 to 3 RTT latency
* Allow enough cushion so that sender is not limited by our window
*/
- if (sysctl_tcp_moderate_rcvbuf)
+ if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf)
rcvmem <<= 2;
if (sk->sk_rcvbuf < rcvmem)
- sk->sk_rcvbuf = min(rcvmem, sysctl_tcp_rmem[2]);
+ sk->sk_rcvbuf = min(rcvmem, sock_net(sk)->ipv4.sysctl_tcp_rmem[2]);
}
/* 4. Try to fixup all. It is made immediately after connection enters
@@ -432,6 +417,7 @@ static void tcp_fixup_rcvbuf(struct sock *sk)
*/
void tcp_init_buffer_space(struct sock *sk)
{
+ int tcp_app_win = sock_net(sk)->ipv4.sysctl_tcp_app_win;
struct tcp_sock *tp = tcp_sk(sk);
int maxwin;
@@ -450,14 +436,14 @@ void tcp_init_buffer_space(struct sock *sk)
if (tp->window_clamp >= maxwin) {
tp->window_clamp = maxwin;
- if (sysctl_tcp_app_win && maxwin > 4 * tp->advmss)
+ if (tcp_app_win && maxwin > 4 * tp->advmss)
tp->window_clamp = max(maxwin -
- (maxwin >> sysctl_tcp_app_win),
+ (maxwin >> tcp_app_win),
4 * tp->advmss);
}
/* Force reservation of one segment. */
- if (sysctl_tcp_app_win &&
+ if (tcp_app_win &&
tp->window_clamp > 2 * tp->advmss &&
tp->window_clamp + tp->advmss > maxwin)
tp->window_clamp = max(2 * tp->advmss, maxwin - tp->advmss);
@@ -471,15 +457,16 @@ static void tcp_clamp_window(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
+ struct net *net = sock_net(sk);
icsk->icsk_ack.quick = 0;
- if (sk->sk_rcvbuf < sysctl_tcp_rmem[2] &&
+ if (sk->sk_rcvbuf < net->ipv4.sysctl_tcp_rmem[2] &&
!(sk->sk_userlocks & SOCK_RCVBUF_LOCK) &&
!tcp_under_memory_pressure(sk) &&
sk_memory_allocated(sk) < sk_prot_mem_limits(sk, 0)) {
sk->sk_rcvbuf = min(atomic_read(&sk->sk_rmem_alloc),
- sysctl_tcp_rmem[2]);
+ net->ipv4.sysctl_tcp_rmem[2]);
}
if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf)
tp->rcv_ssthresh = min(tp->window_clamp, 2U * tp->advmss);
@@ -610,7 +597,7 @@ void tcp_rcv_space_adjust(struct sock *sk)
* <prev RTT . ><current RTT .. ><next RTT .... >
*/
- if (sysctl_tcp_moderate_rcvbuf &&
+ if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf &&
!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
int rcvwin, rcvmem, rcvbuf;
@@ -634,10 +621,11 @@ void tcp_rcv_space_adjust(struct sock *sk)
}
rcvmem = SKB_TRUESIZE(tp->advmss + MAX_TCP_HEADER);
- while (tcp_win_from_space(rcvmem) < tp->advmss)
+ while (tcp_win_from_space(sk, rcvmem) < tp->advmss)
rcvmem += 128;
- rcvbuf = min(rcvwin / tp->advmss * rcvmem, sysctl_tcp_rmem[2]);
+ rcvbuf = min(rcvwin / tp->advmss * rcvmem,
+ sock_net(sk)->ipv4.sysctl_tcp_rmem[2]);
if (rcvbuf > sk->sk_rcvbuf) {
sk->sk_rcvbuf = rcvbuf;
@@ -781,15 +769,6 @@ static void tcp_rtt_estimator(struct sock *sk, long mrtt_us)
tp->srtt_us = max(1U, srtt);
}
-/* Set the sk_pacing_rate to allow proper sizing of TSO packets.
- * Note: TCP stack does not yet implement pacing.
- * FQ packet scheduler can be used to implement cheap but effective
- * TCP pacing, to smooth the burst on large writes when packets
- * in flight is significantly lower than cwnd (or rwin)
- */
-int sysctl_tcp_pacing_ss_ratio __read_mostly = 200;
-int sysctl_tcp_pacing_ca_ratio __read_mostly = 120;
-
static void tcp_update_pacing_rate(struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
@@ -807,9 +786,9 @@ static void tcp_update_pacing_rate(struct sock *sk)
* end of slow start and should slow down.
*/
if (tp->snd_cwnd < tp->snd_ssthresh / 2)
- rate *= sysctl_tcp_pacing_ss_ratio;
+ rate *= sock_net(sk)->ipv4.sysctl_tcp_pacing_ss_ratio;
else
- rate *= sysctl_tcp_pacing_ca_ratio;
+ rate *= sock_net(sk)->ipv4.sysctl_tcp_pacing_ca_ratio;
rate *= max(tp->snd_cwnd, tp->packets_out);
@@ -863,60 +842,46 @@ __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst)
return min_t(__u32, cwnd, tp->snd_cwnd_clamp);
}
-/*
- * Packet counting of FACK is based on in-order assumptions, therefore TCP
- * disables it when reordering is detected
- */
-void tcp_disable_fack(struct tcp_sock *tp)
-{
- /* RFC3517 uses different metric in lost marker => reset on change */
- if (tcp_is_fack(tp))
- tp->lost_skb_hint = NULL;
- tp->rx_opt.sack_ok &= ~TCP_FACK_ENABLED;
-}
-
/* Take a notice that peer is sending D-SACKs */
static void tcp_dsack_seen(struct tcp_sock *tp)
{
tp->rx_opt.sack_ok |= TCP_DSACK_SEEN;
+ tp->rack.dsack_seen = 1;
}
-static void tcp_update_reordering(struct sock *sk, const int metric,
- const int ts)
+/* It's reordering when higher sequence was delivered (i.e. sacked) before
+ * some lower never-retransmitted sequence ("low_seq"). The maximum reordering
+ * distance is approximated in full-mss packet distance ("reordering").
+ */
+static void tcp_check_sack_reordering(struct sock *sk, const u32 low_seq,
+ const int ts)
{
struct tcp_sock *tp = tcp_sk(sk);
- int mib_idx;
+ const u32 mss = tp->mss_cache;
+ u32 fack, metric;
- if (WARN_ON_ONCE(metric < 0))
+ fack = tcp_highest_sack_seq(tp);
+ if (!before(low_seq, fack))
return;
- if (metric > tp->reordering) {
- tp->reordering = min(sysctl_tcp_max_reordering, metric);
-
+ metric = fack - low_seq;
+ if ((metric > tp->reordering * mss) && mss) {
#if FASTRETRANS_DEBUG > 1
pr_debug("Disorder%d %d %u f%u s%u rr%d\n",
tp->rx_opt.sack_ok, inet_csk(sk)->icsk_ca_state,
tp->reordering,
- tp->fackets_out,
+ 0,
tp->sacked_out,
tp->undo_marker ? tp->undo_retrans : 0);
#endif
- tcp_disable_fack(tp);
+ tp->reordering = min_t(u32, (metric + mss - 1) / mss,
+ sock_net(sk)->ipv4.sysctl_tcp_max_reordering);
}
tp->rack.reord = 1;
-
/* This exciting event is worth to be remembered. 8) */
- if (ts)
- mib_idx = LINUX_MIB_TCPTSREORDER;
- else if (tcp_is_reno(tp))
- mib_idx = LINUX_MIB_TCPRENOREORDER;
- else if (tcp_is_fack(tp))
- mib_idx = LINUX_MIB_TCPFACKREORDER;
- else
- mib_idx = LINUX_MIB_TCPSACKREORDER;
-
- NET_INC_STATS(sock_net(sk), mib_idx);
+ NET_INC_STATS(sock_net(sk),
+ ts ? LINUX_MIB_TCPTSREORDER : LINUX_MIB_TCPSACKREORDER);
}
/* This must be called before lost_out is incremented */
@@ -990,7 +955,6 @@ void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, struct sk_buff *skb)
* 3. Loss detection event of two flavors:
* A. Scoreboard estimator decided the packet is lost.
* A'. Reno "three dupacks" marks head of queue lost.
- * A''. Its FACK modification, head until snd.fack is lost.
* B. SACK arrives sacking SND.NXT at the moment, when the
* segment was retransmitted.
* 4. D-SACK added new rule: D-SACK changes any tag to S.
@@ -1133,8 +1097,7 @@ static bool tcp_check_dsack(struct sock *sk, const struct sk_buff *ack_skb,
}
struct tcp_sacktag_state {
- int reord;
- int fack_count;
+ u32 reord;
/* Timestamps for earliest and latest never-retransmitted segment
* that was SACKed. RTO needs the earliest RTT to stay conservative,
* but congestion control should still get an accurate delay signal.
@@ -1143,6 +1106,7 @@ struct tcp_sacktag_state {
u64 last_sackt;
struct rate_sample *rate;
int flag;
+ unsigned int mss_now;
};
/* Check if skb is fully within the SACK block. In presence of GSO skbs,
@@ -1192,7 +1156,8 @@ static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb,
if (pkt_len >= skb->len && !in_sack)
return 0;
- err = tcp_fragment(sk, skb, pkt_len, mss, GFP_ATOMIC);
+ err = tcp_fragment(sk, TCP_FRAG_IN_RTX_QUEUE, skb,
+ pkt_len, mss, GFP_ATOMIC);
if (err < 0)
return err;
}
@@ -1208,15 +1173,15 @@ static u8 tcp_sacktag_one(struct sock *sk,
u64 xmit_time)
{
struct tcp_sock *tp = tcp_sk(sk);
- int fack_count = state->fack_count;
/* Account D-SACK for retransmitted packet. */
if (dup_sack && (sacked & TCPCB_RETRANS)) {
if (tp->undo_marker && tp->undo_retrans > 0 &&
after(end_seq, tp->undo_marker))
tp->undo_retrans--;
- if (sacked & TCPCB_SACKED_ACKED)
- state->reord = min(fack_count, state->reord);
+ if ((sacked & TCPCB_SACKED_ACKED) &&
+ before(start_seq, state->reord))
+ state->reord = start_seq;
}
/* Nothing to do; acked frame is about to be dropped (was ACKed). */
@@ -1242,9 +1207,10 @@ static u8 tcp_sacktag_one(struct sock *sk,
* which was in hole. It is reordering.
*/
if (before(start_seq,
- tcp_highest_sack_seq(tp)))
- state->reord = min(fack_count,
- state->reord);
+ tcp_highest_sack_seq(tp)) &&
+ before(start_seq, state->reord))
+ state->reord = start_seq;
+
if (!after(end_seq, tp->high_seq))
state->flag |= FLAG_ORIG_SACK_ACKED;
if (state->first_sackt == 0)
@@ -1263,15 +1229,10 @@ static u8 tcp_sacktag_one(struct sock *sk,
tp->sacked_out += pcount;
tp->delivered += pcount; /* Out-of-order packets delivered */
- fack_count += pcount;
-
/* Lost marker hint past SACKed? Tweak RFC3517 cnt */
- if (!tcp_is_fack(tp) && tp->lost_skb_hint &&
+ if (tp->lost_skb_hint &&
before(start_seq, TCP_SKB_CB(tp->lost_skb_hint)->seq))
tp->lost_cnt_hint += pcount;
-
- if (fack_count > tp->fackets_out)
- tp->fackets_out = fack_count;
}
/* D-SACK. We can detect redundant retransmission in S|R and plain R
@@ -1289,13 +1250,13 @@ static u8 tcp_sacktag_one(struct sock *sk,
/* Shift newly-SACKed bytes from this skb to the immediately previous
* already-SACKed sk_buff. Mark the newly-SACKed bytes as such.
*/
-static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
+static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *prev,
+ struct sk_buff *skb,
struct tcp_sacktag_state *state,
unsigned int pcount, int shifted, int mss,
bool dup_sack)
{
struct tcp_sock *tp = tcp_sk(sk);
- struct sk_buff *prev = tcp_write_queue_prev(sk, skb);
u32 start_seq = TCP_SKB_CB(skb)->seq; /* start of newly-SACKed */
u32 end_seq = start_seq + shifted; /* end of newly-SACKed */
@@ -1364,8 +1325,7 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
if (unlikely(TCP_SKB_CB(prev)->tx.delivered_mstamp))
TCP_SKB_CB(prev)->tx.delivered_mstamp = 0;
- tcp_unlink_write_queue(skb, sk);
- sk_wmem_free_skb(sk, skb);
+ tcp_rtx_queue_unlink_and_free(skb, sk);
NET_INC_STATS(sock_net(sk), LINUX_MIB_SACKMERGED);
@@ -1415,9 +1375,9 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
goto fallback;
/* Can only happen with delayed DSACK + discard craziness */
- if (unlikely(skb == tcp_write_queue_head(sk)))
+ prev = skb_rb_prev(skb);
+ if (!prev)
goto fallback;
- prev = tcp_write_queue_prev(sk, skb);
if ((TCP_SKB_CB(prev)->sacked & TCPCB_TAGBITS) != TCPCB_SACKED_ACKED)
goto fallback;
@@ -1496,18 +1456,17 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
if (!skb_shift(prev, skb, len))
goto fallback;
- if (!tcp_shifted_skb(sk, skb, state, pcount, len, mss, dup_sack))
+ if (!tcp_shifted_skb(sk, prev, skb, state, pcount, len, mss, dup_sack))
goto out;
/* Hole filled allows collapsing with the next as well, this is very
* useful when hole on every nth skb pattern happens
*/
- if (prev == tcp_write_queue_tail(sk))
+ skb = skb_rb_next(prev);
+ if (!skb)
goto out;
- skb = tcp_write_queue_next(sk, prev);
if (!skb_can_shift(skb) ||
- (skb == tcp_send_head(sk)) ||
((TCP_SKB_CB(skb)->sacked & TCPCB_TAGBITS) != TCPCB_SACKED_ACKED) ||
(mss != tcp_skb_seglen(skb)))
goto out;
@@ -1515,11 +1474,11 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
len = skb->len;
if (skb_shift(prev, skb, len)) {
pcount += tcp_skb_pcount(skb);
- tcp_shifted_skb(sk, skb, state, tcp_skb_pcount(skb), len, mss, 0);
+ tcp_shifted_skb(sk, prev, skb, state, tcp_skb_pcount(skb),
+ len, mss, 0);
}
out:
- state->fack_count += pcount;
return prev;
noop:
@@ -1539,13 +1498,10 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk,
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *tmp;
- tcp_for_write_queue_from(skb, sk) {
+ skb_rbtree_walk_from(skb) {
int in_sack = 0;
bool dup_sack = dup_sack_in;
- if (skb == tcp_send_head(sk))
- break;
-
/* queue is in-order => we can short-circuit the walk early */
if (!before(TCP_SKB_CB(skb)->seq, end_seq))
break;
@@ -1594,34 +1550,48 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk,
tcp_skb_pcount(skb),
skb->skb_mstamp);
tcp_rate_skb_delivered(sk, skb, state->rate);
+ if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)
+ list_del_init(&skb->tcp_tsorted_anchor);
if (!before(TCP_SKB_CB(skb)->seq,
tcp_highest_sack_seq(tp)))
tcp_advance_highest_sack(sk, skb);
}
-
- state->fack_count += tcp_skb_pcount(skb);
}
return skb;
}
-/* Avoid all extra work that is being done by sacktag while walking in
- * a normal way
- */
+static struct sk_buff *tcp_sacktag_bsearch(struct sock *sk,
+ struct tcp_sacktag_state *state,
+ u32 seq)
+{
+ struct rb_node *parent, **p = &sk->tcp_rtx_queue.rb_node;
+ struct sk_buff *skb;
+
+ while (*p) {
+ parent = *p;
+ skb = rb_to_skb(parent);
+ if (before(seq, TCP_SKB_CB(skb)->seq)) {
+ p = &parent->rb_left;
+ continue;
+ }
+ if (!before(seq, TCP_SKB_CB(skb)->end_seq)) {
+ p = &parent->rb_right;
+ continue;
+ }
+ return skb;
+ }
+ return NULL;
+}
+
static struct sk_buff *tcp_sacktag_skip(struct sk_buff *skb, struct sock *sk,
struct tcp_sacktag_state *state,
u32 skip_to_seq)
{
- tcp_for_write_queue_from(skb, sk) {
- if (skb == tcp_send_head(sk))
- break;
-
- if (after(TCP_SKB_CB(skb)->end_seq, skip_to_seq))
- break;
+ if (skb && after(TCP_SKB_CB(skb)->seq, skip_to_seq))
+ return skb;
- state->fack_count += tcp_skb_pcount(skb);
- }
- return skb;
+ return tcp_sacktag_bsearch(sk, state, skip_to_seq);
}
static struct sk_buff *tcp_maybe_skipping_dsack(struct sk_buff *skb,
@@ -1666,13 +1636,10 @@ tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb,
int first_sack_index;
state->flag = 0;
- state->reord = tp->packets_out;
+ state->reord = tp->snd_nxt;
- if (!tp->sacked_out) {
- if (WARN_ON(tp->fackets_out))
- tp->fackets_out = 0;
+ if (!tp->sacked_out)
tcp_highest_sack_reset(sk);
- }
found_dup_sack = tcp_check_dsack(sk, ack_skb, sp_wire,
num_sacks, prior_snd_una);
@@ -1743,8 +1710,8 @@ tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb,
}
}
- skb = tcp_write_queue_head(sk);
- state->fack_count = 0;
+ state->mss_now = tcp_current_mss(sk);
+ skb = NULL;
i = 0;
if (!tp->sacked_out) {
@@ -1801,7 +1768,6 @@ tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb,
skb = tcp_highest_sack(sk);
if (!skb)
break;
- state->fack_count = tp->fackets_out;
cache++;
goto walk;
}
@@ -1816,7 +1782,6 @@ tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb,
skb = tcp_highest_sack(sk);
if (!skb)
break;
- state->fack_count = tp->fackets_out;
}
skb = tcp_sacktag_skip(skb, sk, state, start_seq);
@@ -1836,9 +1801,8 @@ advance_sp:
for (j = 0; j < used_sacks; j++)
tp->recv_sack_cache[i++] = sp[j];
- if ((state->reord < tp->fackets_out) &&
- ((inet_csk(sk)->icsk_ca_state != TCP_CA_Loss) || tp->undo_marker))
- tcp_update_reordering(sk, tp->fackets_out - state->reord, 0);
+ if (inet_csk(sk)->icsk_ca_state != TCP_CA_Loss || tp->undo_marker)
+ tcp_check_sack_reordering(sk, state->reord, 0);
tcp_verify_left_out(tp);
out:
@@ -1876,8 +1840,13 @@ static bool tcp_limit_reno_sacked(struct tcp_sock *tp)
static void tcp_check_reno_reordering(struct sock *sk, const int addend)
{
struct tcp_sock *tp = tcp_sk(sk);
- if (tcp_limit_reno_sacked(tp))
- tcp_update_reordering(sk, tp->packets_out + addend, 0);
+
+ if (!tcp_limit_reno_sacked(tp))
+ return;
+
+ tp->reordering = min_t(u32, tp->packets_out + addend,
+ sock_net(sk)->ipv4.sysctl_tcp_max_reordering);
+ NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRENOREORDER);
}
/* Emulate SACKs for SACKless connection: account for a new dupack. */
@@ -1923,7 +1892,6 @@ void tcp_clear_retrans(struct tcp_sock *tp)
tp->lost_out = 0;
tp->undo_marker = 0;
tp->undo_retrans = -1;
- tp->fackets_out = 0;
tp->sacked_out = 0;
}
@@ -1968,19 +1936,15 @@ void tcp_enter_loss(struct sock *sk)
if (tcp_is_reno(tp))
tcp_reset_reno_sack(tp);
- skb = tcp_write_queue_head(sk);
+ skb = tcp_rtx_queue_head(sk);
is_reneg = skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED);
if (is_reneg) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSACKRENEGING);
tp->sacked_out = 0;
- tp->fackets_out = 0;
}
tcp_clear_all_retrans_hints(tp);
- tcp_for_write_queue(skb, sk) {
- if (skb == tcp_send_head(sk))
- break;
-
+ skb_rbtree_walk_from(skb) {
mark_lost = (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED) ||
is_reneg);
if (mark_lost)
@@ -2014,7 +1978,7 @@ void tcp_enter_loss(struct sock *sk)
* falsely raise the receive window, which results in repeated
* timeouts and stop-and-go behavior.
*/
- tp->frto = sysctl_tcp_frto &&
+ tp->frto = net->ipv4.sysctl_tcp_frto &&
(new_recovery || icsk->icsk_retransmits) &&
!inet_csk(sk)->icsk_mtup.probe_size;
}
@@ -2043,19 +2007,10 @@ static bool tcp_check_sack_reneging(struct sock *sk, int flag)
return false;
}
-static inline int tcp_fackets_out(const struct tcp_sock *tp)
-{
- return tcp_is_reno(tp) ? tp->sacked_out + 1 : tp->fackets_out;
-}
-
/* Heurestics to calculate number of duplicate ACKs. There's no dupACKs
* counter when SACK is enabled (without SACK, sacked_out is used for
* that purpose).
*
- * Instead, with FACK TCP uses fackets_out that includes both SACKed
- * segments up to the highest received SACK block so far and holes in
- * between them.
- *
* With reordering, holes may still be in flight, so RFC3517 recovery
* uses pure sacked_out (total number of SACKed segments) even though
* it violates the RFC that uses duplicate ACKs, often these are equal
@@ -2065,10 +2020,10 @@ static inline int tcp_fackets_out(const struct tcp_sock *tp)
*/
static inline int tcp_dupack_heuristics(const struct tcp_sock *tp)
{
- return tcp_is_fack(tp) ? tp->fackets_out : tp->sacked_out + 1;
+ return tp->sacked_out + 1;
}
-/* Linux NewReno/SACK/FACK/ECN state machine.
+/* Linux NewReno/SACK/ECN state machine.
* --------------------------------------
*
* "Open" Normal state, no dubious events, fast path.
@@ -2133,16 +2088,6 @@ static inline int tcp_dupack_heuristics(const struct tcp_sock *tp)
* dynamically measured and adjusted. This is implemented in
* tcp_rack_mark_lost.
*
- * FACK (Disabled by default. Subsumbed by RACK):
- * It is the simplest heuristics. As soon as we decided
- * that something is lost, we decide that _all_ not SACKed
- * packets until the most forward SACK are lost. I.e.
- * lost_out = fackets_out - sacked_out and left_out = fackets_out.
- * It is absolutely correct estimate, if network does not reorder
- * packets. And it loses any connection to reality when reordering
- * takes place. We use FACK by default until reordering
- * is suspected on the path to this destination.
- *
* If the receiver does not support SACK:
*
* NewReno (RFC6582): in Recovery we assume that one segment
@@ -2191,7 +2136,7 @@ static bool tcp_time_to_recover(struct sock *sk, int flag)
}
/* Detect loss in event "A" above by marking head of queue up as lost.
- * For FACK or non-SACK(Reno) senders, the first "packets" number of segments
+ * For non-SACK(Reno) senders, the first "packets" number of segments
* are considered lost. For RFC3517 SACK, a segment is considered lost if it
* has at least tp->reordering SACKed seqments above it; "packets" refers to
* the maximum SACKed segments to pass before reaching this limit.
@@ -2206,20 +2151,18 @@ static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head)
const u32 loss_high = tcp_is_sack(tp) ? tp->snd_nxt : tp->high_seq;
WARN_ON(packets > tp->packets_out);
- if (tp->lost_skb_hint) {
- skb = tp->lost_skb_hint;
- cnt = tp->lost_cnt_hint;
+ skb = tp->lost_skb_hint;
+ if (skb) {
/* Head already handled? */
- if (mark_head && skb != tcp_write_queue_head(sk))
+ if (mark_head && after(TCP_SKB_CB(skb)->seq, tp->snd_una))
return;
+ cnt = tp->lost_cnt_hint;
} else {
- skb = tcp_write_queue_head(sk);
+ skb = tcp_rtx_queue_head(sk);
cnt = 0;
}
- tcp_for_write_queue_from(skb, sk) {
- if (skb == tcp_send_head(sk))
- break;
+ skb_rbtree_walk_from(skb) {
/* TODO: do this better */
/* this is not the most efficient way to do this... */
tp->lost_skb_hint = skb;
@@ -2229,12 +2172,12 @@ static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head)
break;
oldcnt = cnt;
- if (tcp_is_fack(tp) || tcp_is_reno(tp) ||
+ if (tcp_is_reno(tp) ||
(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))
cnt += tcp_skb_pcount(skb);
if (cnt > packets) {
- if ((tcp_is_sack(tp) && !tcp_is_fack(tp)) ||
+ if (tcp_is_sack(tp) ||
(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED) ||
(oldcnt >= packets))
break;
@@ -2243,7 +2186,8 @@ static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head)
/* If needed, chop off the prefix to mark as lost. */
lost = (packets - oldcnt) * mss;
if (lost < skb->len &&
- tcp_fragment(sk, skb, lost, mss, GFP_ATOMIC) < 0)
+ tcp_fragment(sk, TCP_FRAG_IN_RTX_QUEUE, skb,
+ lost, mss, GFP_ATOMIC) < 0)
break;
cnt = packets;
}
@@ -2264,11 +2208,6 @@ static void tcp_update_scoreboard(struct sock *sk, int fast_rexmit)
if (tcp_is_reno(tp)) {
tcp_mark_head_lost(sk, 1, 1);
- } else if (tcp_is_fack(tp)) {
- int lost = tp->fackets_out - tp->reordering;
- if (lost <= 0)
- lost = 1;
- tcp_mark_head_lost(sk, lost, 0);
} else {
int sacked_upto = tp->sacked_out - tp->reordering;
if (sacked_upto >= 0)
@@ -2327,16 +2266,16 @@ static bool tcp_any_retrans_done(const struct sock *sk)
if (tp->retrans_out)
return true;
- skb = tcp_write_queue_head(sk);
+ skb = tcp_rtx_queue_head(sk);
if (unlikely(skb && TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS))
return true;
return false;
}
-#if FASTRETRANS_DEBUG > 1
static void DBGUNDO(struct sock *sk, const char *msg)
{
+#if FASTRETRANS_DEBUG > 1
struct tcp_sock *tp = tcp_sk(sk);
struct inet_sock *inet = inet_sk(sk);
@@ -2358,10 +2297,8 @@ static void DBGUNDO(struct sock *sk, const char *msg)
tp->packets_out);
}
#endif
-}
-#else
-#define DBGUNDO(x...) do { } while (0)
#endif
+}
static void tcp_undo_cwnd_reduction(struct sock *sk, bool unmark_loss)
{
@@ -2370,9 +2307,7 @@ static void tcp_undo_cwnd_reduction(struct sock *sk, bool unmark_loss)
if (unmark_loss) {
struct sk_buff *skb;
- tcp_for_write_queue(skb, sk) {
- if (skb == tcp_send_head(sk))
- break;
+ skb_rbtree_walk(skb, &sk->tcp_rtx_queue) {
TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
}
tp->lost_out = 0;
@@ -2417,6 +2352,8 @@ static bool tcp_try_undo_recovery(struct sock *sk)
mib_idx = LINUX_MIB_TCPFULLUNDO;
NET_INC_STATS(sock_net(sk), mib_idx);
+ } else if (tp->rack.reo_wnd_persist) {
+ tp->rack.reo_wnd_persist--;
}
if (tp->snd_una == tp->high_seq && tcp_is_reno(tp)) {
/* Hold old state until something *above* high_seq
@@ -2436,6 +2373,8 @@ static bool tcp_try_undo_dsack(struct sock *sk)
struct tcp_sock *tp = tcp_sk(sk);
if (tp->undo_marker && !tp->undo_retrans) {
+ tp->rack.reo_wnd_persist = min(TCP_RACK_RECOVERY_THRESH,
+ tp->rack.reo_wnd_persist + 1);
DBGUNDO(sk, "D-SACK");
tcp_undo_cwnd_reduction(sk, false);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPDSACKUNDO);
@@ -2616,9 +2555,7 @@ void tcp_simple_retransmit(struct sock *sk)
struct sk_buff *skb;
unsigned int mss = tcp_current_mss(sk);
- tcp_for_write_queue(skb, sk) {
- if (skb == tcp_send_head(sk))
- break;
+ skb_rbtree_walk(skb, &sk->tcp_rtx_queue) {
if (tcp_skb_seglen(skb) > mss &&
!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) {
if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS) {
@@ -2712,7 +2649,7 @@ static void tcp_process_loss(struct sock *sk, int flag, bool is_dupack,
* is updated in tcp_ack()). Otherwise fall back to
* the conventional recovery.
*/
- if (tcp_send_head(sk) &&
+ if (!tcp_write_queue_empty(sk) &&
after(tcp_wnd_end(tp), tp->snd_nxt)) {
*rexmit = REXMIT_NEW;
return;
@@ -2739,15 +2676,15 @@ static void tcp_process_loss(struct sock *sk, int flag, bool is_dupack,
}
/* Undo during fast recovery after partial ACK. */
-static bool tcp_try_undo_partial(struct sock *sk, const int acked)
+static bool tcp_try_undo_partial(struct sock *sk, u32 prior_snd_una)
{
struct tcp_sock *tp = tcp_sk(sk);
if (tp->undo_marker && tcp_packet_delayed(tp)) {
/* Plain luck! Hole if filled with delayed
- * packet, rather than with a retransmit.
+ * packet, rather than with a retransmit. Check reordering.
*/
- tcp_update_reordering(sk, tcp_fackets_out(tp) + acked, 1);
+ tcp_check_sack_reordering(sk, prior_snd_una, 1);
/* We are getting evidence that the reordering degree is higher
* than we realized. If there are no retransmits out then we
@@ -2774,7 +2711,7 @@ static void tcp_rack_identify_loss(struct sock *sk, int *ack_flag)
struct tcp_sock *tp = tcp_sk(sk);
/* Use RACK to detect loss */
- if (sysctl_tcp_recovery & TCP_RACK_LOSS_DETECTION) {
+ if (sock_net(sk)->ipv4.sysctl_tcp_recovery & TCP_RACK_LOSS_DETECTION) {
u32 prior_retrans = tp->retrans_out;
tcp_rack_mark_lost(sk);
@@ -2783,6 +2720,14 @@ static void tcp_rack_identify_loss(struct sock *sk, int *ack_flag)
}
}
+static bool tcp_force_fast_retransmit(struct sock *sk)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ return after(tcp_highest_sack_seq(tp),
+ tp->snd_una + tp->reordering * tp->mss_cache);
+}
+
/* Process an event, which can update packets-in-flight not trivially.
* Main goal of this function is to calculate new estimate for left_out,
* taking into account both packets sitting in receiver's buffer and
@@ -2795,19 +2740,17 @@ static void tcp_rack_identify_loss(struct sock *sk, int *ack_flag)
* It does _not_ decide what to send, it is made in function
* tcp_xmit_retransmit_queue().
*/
-static void tcp_fastretrans_alert(struct sock *sk, const int acked,
+static void tcp_fastretrans_alert(struct sock *sk, const u32 prior_snd_una,
bool is_dupack, int *ack_flag, int *rexmit)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
int fast_rexmit = 0, flag = *ack_flag;
bool do_lost = is_dupack || ((flag & FLAG_DATA_SACKED) &&
- (tcp_fackets_out(tp) > tp->reordering));
+ tcp_force_fast_retransmit(sk));
- if (WARN_ON(!tp->packets_out && tp->sacked_out))
+ if (!tp->packets_out && tp->sacked_out)
tp->sacked_out = 0;
- if (WARN_ON(!tp->sacked_out && tp->fackets_out))
- tp->fackets_out = 0;
/* Now state machine starts.
* A. ECE, hence prohibit cwnd undoing, the reduction is required. */
@@ -2854,11 +2797,11 @@ static void tcp_fastretrans_alert(struct sock *sk, const int acked,
if (tcp_is_reno(tp) && is_dupack)
tcp_add_reno_sack(sk);
} else {
- if (tcp_try_undo_partial(sk, acked))
+ if (tcp_try_undo_partial(sk, prior_snd_una))
return;
/* Partial ACK arrived. Force fast retransmit. */
do_lost = tcp_is_reno(tp) ||
- tcp_fackets_out(tp) > tp->reordering;
+ tcp_force_fast_retransmit(sk);
}
if (tcp_try_undo_dsack(sk)) {
tcp_try_keep_open(sk);
@@ -2873,6 +2816,7 @@ static void tcp_fastretrans_alert(struct sock *sk, const int acked,
(*ack_flag & FLAG_LOST_RETRANS)))
return;
/* Change state if cwnd is undone or retransmits are lost */
+ /* fall through */
default:
if (tcp_is_reno(tp)) {
if (flag & FLAG_SND_UNA_ADVANCED)
@@ -2913,8 +2857,8 @@ static void tcp_fastretrans_alert(struct sock *sk, const int acked,
static void tcp_update_rtt_min(struct sock *sk, u32 rtt_us)
{
+ u32 wlen = sock_net(sk)->ipv4.sysctl_tcp_min_rtt_wlen * HZ;
struct tcp_sock *tp = tcp_sk(sk);
- u32 wlen = sysctl_tcp_min_rtt_wlen * HZ;
minmax_running_min(&tp->rtt_min, wlen, tcp_jiffies32,
rtt_us ? : jiffies_to_usecs(1));
@@ -3056,28 +3000,31 @@ static void tcp_ack_tstamp(struct sock *sk, struct sk_buff *skb,
shinfo = skb_shinfo(skb);
if (!before(shinfo->tskey, prior_snd_una) &&
- before(shinfo->tskey, tcp_sk(sk)->snd_una))
- __skb_tstamp_tx(skb, NULL, sk, SCM_TSTAMP_ACK);
+ before(shinfo->tskey, tcp_sk(sk)->snd_una)) {
+ tcp_skb_tsorted_save(skb) {
+ __skb_tstamp_tx(skb, NULL, sk, SCM_TSTAMP_ACK);
+ } tcp_skb_tsorted_restore(skb);
+ }
}
/* Remove acknowledged frames from the retransmission queue. If our packet
* is before the ack sequence we can discard it as it's confirmed to have
* arrived at the other end.
*/
-static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
- u32 prior_snd_una, int *acked,
+static int tcp_clean_rtx_queue(struct sock *sk, u32 prior_fack,
+ u32 prior_snd_una,
struct tcp_sacktag_state *sack)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
u64 first_ackt, last_ackt;
struct tcp_sock *tp = tcp_sk(sk);
u32 prior_sacked = tp->sacked_out;
- u32 reord = tp->packets_out;
+ u32 reord = tp->snd_nxt; /* lowest acked un-retx un-sacked seq */
+ struct sk_buff *skb, *next;
bool fully_acked = true;
long sack_rtt_us = -1L;
long seq_rtt_us = -1L;
long ca_rtt_us = -1L;
- struct sk_buff *skb;
u32 pkts_acked = 0;
u32 last_in_flight = 0;
bool rtt_update;
@@ -3085,8 +3032,9 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
first_ackt = 0;
- while ((skb = tcp_write_queue_head(sk)) && skb != tcp_send_head(sk)) {
+ for (skb = skb_rb_first(&sk->tcp_rtx_queue); skb; skb = next) {
struct tcp_skb_cb *scb = TCP_SKB_CB(skb);
+ const u32 start_seq = scb->seq;
u8 sacked = scb->sacked;
u32 acked_pcount;
@@ -3103,8 +3051,6 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
break;
fully_acked = false;
} else {
- /* Speedup tcp_unlink_write_queue() and next loop */
- prefetchw(skb->next);
acked_pcount = tcp_skb_pcount(skb);
}
@@ -3119,7 +3065,8 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
first_ackt = last_ackt;
last_in_flight = TCP_SKB_CB(skb)->tx.in_flight;
- reord = min(pkts_acked, reord);
+ if (before(start_seq, reord))
+ reord = start_seq;
if (!after(scb->end_seq, tp->high_seq))
flag |= FLAG_ORIG_SACK_ACKED;
}
@@ -3156,12 +3103,12 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
if (!fully_acked)
break;
- tcp_unlink_write_queue(skb, sk);
- sk_wmem_free_skb(sk, skb);
+ next = skb_rb_next(skb);
if (unlikely(skb == tp->retransmit_skb_hint))
tp->retransmit_skb_hint = NULL;
if (unlikely(skb == tp->lost_skb_hint))
tp->lost_skb_hint = NULL;
+ tcp_rtx_queue_unlink_and_free(skb, sk);
}
if (!skb)
@@ -3197,16 +3144,12 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
int delta;
/* Non-retransmitted hole got filled? That's reordering */
- if (reord < prior_fackets && reord <= tp->fackets_out)
- tcp_update_reordering(sk, tp->fackets_out - reord, 0);
+ if (before(reord, prior_fack))
+ tcp_check_sack_reordering(sk, reord, 0);
- delta = tcp_is_fack(tp) ? pkts_acked :
- prior_sacked - tp->sacked_out;
+ delta = prior_sacked - tp->sacked_out;
tp->lost_cnt_hint -= min(tp->lost_cnt_hint, delta);
}
-
- tp->fackets_out -= min(pkts_acked, tp->fackets_out);
-
} e