int sysctl_tcp_window_scaling __read_mostly = 1;
int sysctl_tcp_sack __read_mostly = 1;
int sysctl_tcp_fack __read_mostly = 1;
-int sysctl_tcp_reordering __read_mostly = TCP_FASTRETRANS_THRESH;
int sysctl_tcp_max_reordering __read_mostly = 300;
-EXPORT_SYMBOL(sysctl_tcp_reordering);
int sysctl_tcp_dsack __read_mostly = 1;
int sysctl_tcp_app_win __read_mostly = 31;
int sysctl_tcp_adv_win_scale __read_mostly = 1;
#define TCP_REMNANT (TCP_FLAG_FIN|TCP_FLAG_URG|TCP_FLAG_SYN|TCP_FLAG_PSH)
#define TCP_HP_BITS (~(TCP_RESERVED_BITS|TCP_FLAG_PSH))
+#define REXMIT_NONE 0 /* no loss recovery to do */
+#define REXMIT_LOST 1 /* retransmit packets marked lost */
+#define REXMIT_NEW 2 /* FRTO-style transmit of unsent/new packets */
+
/* Adapt the MSS value used to make delayed ack decision to the
* real world.
*/
sacked |= TCPCB_SACKED_ACKED;
state->flag |= FLAG_DATA_SACKED;
tp->sacked_out += pcount;
+ tp->delivered += pcount; /* Out-of-order packets delivered */
fack_count += pcount;
static void tcp_add_reno_sack(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
+ u32 prior_sacked = tp->sacked_out;
+
tp->sacked_out++;
tcp_check_reno_reordering(sk, 0);
+ if (tp->sacked_out > prior_sacked)
+ tp->delivered++; /* Some out-of-order packet is delivered */
tcp_verify_left_out(tp);
}
if (acked > 0) {
/* One ACK acked hole. The rest eat duplicate ACKs. */
+ tp->delivered += max_t(int, acked - tp->sacked_out, 1);
if (acked - 1 >= tp->sacked_out)
tp->sacked_out = 0;
else
{
const struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
+ struct net *net = sock_net(sk);
struct sk_buff *skb;
bool new_recovery = icsk->icsk_ca_state < TCP_CA_Recovery;
bool is_reneg; /* is receiver reneging on SACKs? */
* suggests that the degree of reordering is over-estimated.
*/
if (icsk->icsk_ca_state <= TCP_CA_Disorder &&
- tp->sacked_out >= sysctl_tcp_reordering)
+ tp->sacked_out >= net->ipv4.sysctl_tcp_reordering)
tp->reordering = min_t(unsigned int, tp->reordering,
- sysctl_tcp_reordering);
+ net->ipv4.sysctl_tcp_reordering);
tcp_set_ca_state(sk, TCP_CA_Loss);
tp->high_seq = tp->snd_nxt;
tcp_ecn_queue_cwr(tp);
{
struct tcp_sock *tp = tcp_sk(sk);
__u32 packets_out;
+ int tcp_reordering = sock_net(sk)->ipv4.sysctl_tcp_reordering;
/* Trick#1: The loss is proven. */
if (tp->lost_out)
*/
packets_out = tp->packets_out;
if (packets_out <= tp->reordering &&
- tp->sacked_out >= max_t(__u32, packets_out/2, sysctl_tcp_reordering) &&
+ tp->sacked_out >= max_t(__u32, packets_out/2, tcp_reordering) &&
!tcp_may_send_now(sk)) {
/* We have nothing to send. This connection is limited
* either by receiver window or by application.
tcp_ecn_queue_cwr(tp);
}
-static void tcp_cwnd_reduction(struct sock *sk, const int prior_unsacked,
- int fast_rexmit, int flag)
+static void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked,
+ int flag)
{
struct tcp_sock *tp = tcp_sk(sk);
int sndcnt = 0;
int delta = tp->snd_ssthresh - tcp_packets_in_flight(tp);
- int newly_acked_sacked = prior_unsacked -
- (tp->packets_out - tp->sacked_out);
if (newly_acked_sacked <= 0 || WARN_ON_ONCE(!tp->prior_cwnd))
return;
} else {
sndcnt = min(delta, newly_acked_sacked);
}
- sndcnt = max(sndcnt, (fast_rexmit ? 1 : 0));
+ /* Force a fast retransmit upon entering fast recovery */
+ sndcnt = max(sndcnt, (tp->prr_out ? 0 : 1));
tp->snd_cwnd = tcp_packets_in_flight(tp) + sndcnt;
}
}
}
-static void tcp_try_to_open(struct sock *sk, int flag, const int prior_unsacked)
+static void tcp_try_to_open(struct sock *sk, int flag)
{
struct tcp_sock *tp = tcp_sk(sk);
if (inet_csk(sk)->icsk_ca_state != TCP_CA_CWR) {
tcp_try_keep_open(sk);
- } else {
- tcp_cwnd_reduction(sk, prior_unsacked, 0, flag);
}
}
/* Process an ACK in CA_Loss state. Move to CA_Open if lost data are
* recovered or spurious. Otherwise retransmits more on partial ACKs.
*/
-static void tcp_process_loss(struct sock *sk, int flag, bool is_dupack)
+static void tcp_process_loss(struct sock *sk, int flag, bool is_dupack,
+ int *rexmit)
{
struct tcp_sock *tp = tcp_sk(sk);
bool recovered = !before(tp->snd_una, tp->high_seq);
tp->frto = 0; /* Step 3.a. loss was real */
} else if (flag & FLAG_SND_UNA_ADVANCED && !recovered) {
tp->high_seq = tp->snd_nxt;
- __tcp_push_pending_frames(sk, tcp_current_mss(sk),
- TCP_NAGLE_OFF);
- if (after(tp->snd_nxt, tp->high_seq))
- return; /* Step 2.b */
+ /* Step 2.b. Try send new data (but deferred until cwnd
+ * is updated in tcp_ack()). Otherwise fall back to
+ * the conventional recovery.
+ */
+ if (tcp_send_head(sk) &&
+ after(tcp_wnd_end(tp), tp->snd_nxt)) {
+ *rexmit = REXMIT_NEW;
+ return;
+ }
tp->frto = 0;
}
}
else if (flag & FLAG_SND_UNA_ADVANCED)
tcp_reset_reno_sack(tp);
}
- tcp_xmit_retransmit_queue(sk);
+ *rexmit = REXMIT_LOST;
}
/* Undo during fast recovery after partial ACK. */
-static bool tcp_try_undo_partial(struct sock *sk, const int acked,
- const int prior_unsacked, int flag)
+static bool tcp_try_undo_partial(struct sock *sk, const int acked)
{
struct tcp_sock *tp = tcp_sk(sk);
* can undo. Otherwise we clock out new packets but do not
* mark more packets lost or retransmit more.
*/
- if (tp->retrans_out) {
- tcp_cwnd_reduction(sk, prior_unsacked, 0, flag);
+ if (tp->retrans_out)
return true;
- }
if (!tcp_any_retrans_done(sk))
tp->retrans_stamp = 0;
* taking into account both packets sitting in receiver's buffer and
* packets lost by network.
*
- * Besides that it does CWND reduction, when packet loss is detected
- * and changes state of machine.
+ * Besides that it updates the congestion state when packet loss or ECN
+ * is detected. But it does not reduce the cwnd, it is done by the
+ * congestion control later.
*
* 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,
- const int prior_unsacked,
- bool is_dupack, int flag)
+ 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));
- int fast_rexmit = 0;
if (WARN_ON(!tp->packets_out && tp->sacked_out))
tp->sacked_out = 0;
/* Use RACK to detect loss */
if (sysctl_tcp_recovery & TCP_RACK_LOST_RETRANS &&
- tcp_rack_mark_lost(sk))
+ tcp_rack_mark_lost(sk)) {
flag |= FLAG_LOST_RETRANS;
+ *ack_flag |= FLAG_LOST_RETRANS;
+ }
/* E. Process state. */
switch (icsk->icsk_ca_state) {
if (tcp_is_reno(tp) && is_dupack)
tcp_add_reno_sack(sk);
} else {
- if (tcp_try_undo_partial(sk, acked, prior_unsacked, flag))
+ if (tcp_try_undo_partial(sk, acked))
return;
/* Partial ACK arrived. Force fast retransmit. */
do_lost = tcp_is_reno(tp) ||
}
break;
case TCP_CA_Loss:
- tcp_process_loss(sk, flag, is_dupack);
+ tcp_process_loss(sk, flag, is_dupack, rexmit);
if (icsk->icsk_ca_state != TCP_CA_Open &&
!(flag & FLAG_LOST_RETRANS))
return;
tcp_try_undo_dsack(sk);
if (!tcp_time_to_recover(sk, flag)) {
- tcp_try_to_open(sk, flag, prior_unsacked);
+ tcp_try_to_open(sk, flag);
return;
}
if (do_lost)
tcp_update_scoreboard(sk, fast_rexmit);
- tcp_cwnd_reduction(sk, prior_unsacked, fast_rexmit, flag);
- tcp_xmit_retransmit_queue(sk);
+ *rexmit = REXMIT_LOST;
}
/* Kathleen Nichols' algorithm for tracking the minimum value of
* arrived at the other end.
*/
static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
- u32 prior_snd_una,
+ u32 prior_snd_una, int *acked,
struct tcp_sacktag_state *sack)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
flag |= FLAG_ORIG_SACK_ACKED;
}
- if (sacked & TCPCB_SACKED_ACKED)
+ if (sacked & TCPCB_SACKED_ACKED) {
tp->sacked_out -= acked_pcount;
- else if (tcp_is_sack(tp) && !tcp_skb_spurious_retrans(tp, skb))
- tcp_rack_advance(tp, &skb->skb_mstamp, sacked);
+ } else if (tcp_is_sack(tp)) {
+ tp->delivered += acked_pcount;
+ if (!tcp_skb_spurious_retrans(tp, skb))
+ tcp_rack_advance(tp, &skb->skb_mstamp, sacked);
+ }
if (sacked & TCPCB_LOST)
tp->lost_out -= acked_pcount;
}
}
#endif
+ *acked = pkts_acked;
return flag;
}
/* Decide wheather to run the increase function of congestion control. */
static inline bool tcp_may_raise_cwnd(const struct sock *sk, const int flag)
{
- if (tcp_in_cwnd_reduction(sk))
- return false;
-
/* If reordering is high then always grow cwnd whenever data is
* delivered regardless of its ordering. Otherwise stay conservative
* and only grow cwnd on in-order delivery (RFC5681). A stretched ACK w/
* new SACK or ECE mark may first advance cwnd here and later reduce
* cwnd in tcp_fastretrans_alert() based on more states.
*/
- if (tcp_sk(sk)->reordering > sysctl_tcp_reordering)
+ if (tcp_sk(sk)->reordering > sock_net(sk)->ipv4.sysctl_tcp_reordering)
return flag & FLAG_FORWARD_PROGRESS;
return flag & FLAG_DATA_ACKED;
}
+/* The "ultimate" congestion control function that aims to replace the rigid
+ * cwnd increase and decrease control (tcp_cong_avoid,tcp_*cwnd_reduction).
+ * It's called toward the end of processing an ACK with precise rate
+ * information. All transmission or retransmission are delayed afterwards.
+ */
+static void tcp_cong_control(struct sock *sk, u32 ack, u32 acked_sacked,
+ int flag)
+{
+ if (tcp_in_cwnd_reduction(sk)) {
+ /* Reduce cwnd if state mandates */
+ tcp_cwnd_reduction(sk, acked_sacked, flag);
+ } else if (tcp_may_raise_cwnd(sk, flag)) {
+ /* Advance cwnd if state allows */
+ tcp_cong_avoid(sk, ack, acked_sacked);
+ }
+ tcp_update_pacing_rate(sk);
+}
+
/* Check that window update is acceptable.
* The function assumes that snd_una<=ack<=snd_next.
*/
icsk->icsk_ca_ops->in_ack_event(sk, flags);
}
+/* Congestion control has updated the cwnd already. So if we're in
+ * loss recovery then now we do any new sends (for FRTO) or
+ * retransmits (for CA_Loss or CA_recovery) that make sense.
+ */
+static void tcp_xmit_recovery(struct sock *sk, int rexmit)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ if (rexmit == REXMIT_NONE)
+ return;
+
+ if (unlikely(rexmit == 2)) {
+ __tcp_push_pending_frames(sk, tcp_current_mss(sk),
+ TCP_NAGLE_OFF);
+ if (after(tp->snd_nxt, tp->high_seq))
+ return;
+ tp->frto = 0;
+ }
+ tcp_xmit_retransmit_queue(sk);
+}
+
/* This routine deals with incoming acks, but not outgoing ones. */
static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
{
bool is_dupack = false;
u32 prior_fackets;
int prior_packets = tp->packets_out;
- const int prior_unsacked = tp->packets_out - tp->sacked_out;
+ u32 prior_delivered = tp->delivered;
int acked = 0; /* Number of packets newly acked */
+ int rexmit = REXMIT_NONE; /* Flag to (re)transmit to recover losses */
sack_state.first_sackt.v64 = 0;
goto no_queue;
/* See if we can take anything off of the retransmit queue. */
- acked = tp->packets_out;
- flag |= tcp_clean_rtx_queue(sk, prior_fackets, prior_snd_una,
+ flag |= tcp_clean_rtx_queue(sk, prior_fackets, prior_snd_una, &acked,
&sack_state);
- acked -= tp->packets_out;
if (tcp_ack_is_dubious(sk, flag)) {
is_dupack = !(flag & (FLAG_SND_UNA_ADVANCED | FLAG_NOT_DUP));
- tcp_fastretrans_alert(sk, acked, prior_unsacked,
- is_dupack, flag);
+ tcp_fastretrans_alert(sk, acked, is_dupack, &flag, &rexmit);
}
if (tp->tlp_high_seq)
tcp_process_tlp_ack(sk, ack, flag);
- /* Advance cwnd if state allows */
- if (tcp_may_raise_cwnd(sk, flag))
- tcp_cong_avoid(sk, ack, acked);
-
if ((flag & FLAG_FORWARD_PROGRESS) || !(flag & FLAG_NOT_DUP)) {
struct dst_entry *dst = __sk_dst_get(sk);
if (dst)
if (icsk->icsk_pending == ICSK_TIME_RETRANS)
tcp_schedule_loss_probe(sk);
- tcp_update_pacing_rate(sk);
+ tcp_cong_control(sk, ack, tp->delivered - prior_delivered, flag);
+ tcp_xmit_recovery(sk, rexmit);
return 1;
no_queue:
/* If data was DSACKed, see if we can undo a cwnd reduction. */
if (flag & FLAG_DSACKING_ACK)
- tcp_fastretrans_alert(sk, acked, prior_unsacked,
- is_dupack, flag);
+ tcp_fastretrans_alert(sk, acked, is_dupack, &flag, &rexmit);
/* If this ack opens up a zero window, clear backoff. It was
* being used to time the probes, and is probably far higher than
* it needs to be for normal retransmission.
if (TCP_SKB_CB(skb)->sacked) {
flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una,
&sack_state);
- tcp_fastretrans_alert(sk, acked, prior_unsacked,
- is_dupack, flag);
+ tcp_fastretrans_alert(sk, acked, is_dupack, &flag, &rexmit);
+ tcp_xmit_recovery(sk, rexmit);
}
SOCK_DEBUG(sk, "Ack %u before %u:%u\n", ack, tp->snd_una, tp->snd_nxt);
*
* If we are in FINWAIT-2, a received FIN moves us to TIME-WAIT.
*/
-static void tcp_fin(struct sock *sk)
+void tcp_fin(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
tp->syn_data_acked = tp->syn_data;
if (tp->syn_data_acked)
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPFASTOPENACTIVE);
+
+ tcp_fastopen_add_skb(sk, synack);
+
return false;
}
struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
const char *msg = "Dropping request";
bool want_cookie = false;
+ struct net *net = sock_net(sk);
#ifdef CONFIG_SYN_COOKIES
- if (sysctl_tcp_syncookies) {
+ if (net->ipv4.sysctl_tcp_syncookies) {
msg = "Sending cookies";
want_cookie = true;
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);
if (!queue->synflood_warned &&
- sysctl_tcp_syncookies != 2 &&
+ net->ipv4.sysctl_tcp_syncookies != 2 &&
xchg(&queue->synflood_warned, 1) == 0)
pr_info("%s: Possible SYN flooding on port %d. %s. Check SNMP counters.\n",
proto, ntohs(tcp_hdr(skb)->dest), msg);
__u32 isn = TCP_SKB_CB(skb)->tcp_tw_isn;
struct tcp_options_received tmp_opt;
struct tcp_sock *tp = tcp_sk(sk);
+ struct net *net = sock_net(sk);
struct sock *fastopen_sk = NULL;
struct dst_entry *dst = NULL;
struct request_sock *req;
* limitations, they conserve resources and peer is
* evidently real one.
*/
- if ((sysctl_tcp_syncookies == 2 ||
+ if ((net->ipv4.sysctl_tcp_syncookies == 2 ||
inet_csk_reqsk_queue_is_full(sk)) && !isn) {
want_cookie = tcp_syn_flood_action(sk, skb, rsk_ops->slab_name);
if (!want_cookie)
}
}
/* Kill the following clause, if you dislike this way. */
- else if (!sysctl_tcp_syncookies &&
+ else if (!net->ipv4.sysctl_tcp_syncookies &&
(sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
(sysctl_max_syn_backlog >> 2)) &&
!tcp_peer_is_proven(req, dst, false,
projects / linux-2.6-block.git / blobdiff