diff options
Diffstat (limited to 'net/ipv4/tcp_input.c')
| -rw-r--r-- | net/ipv4/tcp_input.c | 612 |
1 files changed, 387 insertions, 225 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 257b61789eeb..cfa2aa128342 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -99,6 +99,7 @@ int sysctl_tcp_thin_dupack __read_mostly; int sysctl_tcp_moderate_rcvbuf __read_mostly = 1; int sysctl_tcp_abc __read_mostly; +int sysctl_tcp_early_retrans __read_mostly = 2; #define FLAG_DATA 0x01 /* Incoming frame contained data. */ #define FLAG_WIN_UPDATE 0x02 /* Incoming ACK was a window update. */ @@ -175,7 +176,7 @@ static void tcp_measure_rcv_mss(struct sock *sk, const struct sk_buff *skb) static void tcp_incr_quickack(struct sock *sk) { struct inet_connection_sock *icsk = inet_csk(sk); - unsigned quickacks = tcp_sk(sk)->rcv_wnd / (2 * icsk->icsk_ack.rcv_mss); + unsigned int quickacks = tcp_sk(sk)->rcv_wnd / (2 * icsk->icsk_ack.rcv_mss); if (quickacks == 0) quickacks = 2; @@ -195,9 +196,10 @@ static void tcp_enter_quickack_mode(struct sock *sk) * and the session is not interactive. */ -static inline int tcp_in_quickack_mode(const struct sock *sk) +static inline bool tcp_in_quickack_mode(const struct sock *sk) { const struct inet_connection_sock *icsk = inet_csk(sk); + return icsk->icsk_ack.quick && !icsk->icsk_ack.pingpong; } @@ -252,11 +254,11 @@ static inline void TCP_ECN_rcv_syn(struct tcp_sock *tp, const struct tcphdr *th) tp->ecn_flags &= ~TCP_ECN_OK; } -static inline int TCP_ECN_rcv_ecn_echo(const struct tcp_sock *tp, const struct tcphdr *th) +static bool TCP_ECN_rcv_ecn_echo(const struct tcp_sock *tp, const struct tcphdr *th) { if (th->ece && !th->syn && (tp->ecn_flags & TCP_ECN_OK)) - return 1; - return 0; + return true; + return false; } /* Buffer size and advertised window tuning. @@ -906,6 +908,7 @@ static void tcp_init_metrics(struct sock *sk) if (dst_metric(dst, RTAX_REORDERING) && tp->reordering != dst_metric(dst, RTAX_REORDERING)) { tcp_disable_fack(tp); + tcp_disable_early_retrans(tp); tp->reordering = dst_metric(dst, RTAX_REORDERING); } @@ -937,7 +940,7 @@ static void tcp_init_metrics(struct sock *sk) tcp_set_rto(sk); reset: if (tp->srtt == 0) { - /* RFC2988bis: We've failed to get a valid RTT sample from + /* RFC6298: 5.7 We've failed to get a valid RTT sample from * 3WHS. This is most likely due to retransmission, * including spurious one. Reset the RTO back to 3secs * from the more aggressive 1sec to avoid more spurious @@ -947,7 +950,7 @@ reset: inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK; } /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been - * retransmitted. In light of RFC2988bis' more aggressive 1sec + * retransmitted. In light of RFC6298 more aggressive 1sec * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK * retransmission has occurred. */ @@ -979,15 +982,18 @@ static void tcp_update_reordering(struct sock *sk, const int metric, NET_INC_STATS_BH(sock_net(sk), mib_idx); #if FASTRETRANS_DEBUG > 1 - printk(KERN_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, - tp->sacked_out, - tp->undo_marker ? tp->undo_retrans : 0); + 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, + tp->sacked_out, + tp->undo_marker ? tp->undo_retrans : 0); #endif tcp_disable_fack(tp); } + + if (metric > 0) + tcp_disable_early_retrans(tp); } /* This must be called before lost_out is incremented */ @@ -1118,36 +1124,36 @@ static void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, * the exact amount is rather hard to quantify. However, tp->max_window can * be used as an exaggerated estimate. */ -static int tcp_is_sackblock_valid(struct tcp_sock *tp, int is_dsack, - u32 start_seq, u32 end_seq) +static bool tcp_is_sackblock_valid(struct tcp_sock *tp, bool is_dsack, + u32 start_seq, u32 end_seq) { /* Too far in future, or reversed (interpretation is ambiguous) */ if (after(end_seq, tp->snd_nxt) || !before(start_seq, end_seq)) - return 0; + return false; /* Nasty start_seq wrap-around check (see comments above) */ if (!before(start_seq, tp->snd_nxt)) - return 0; + return false; /* In outstanding window? ...This is valid exit for D-SACKs too. * start_seq == snd_una is non-sensical (see comments above) */ if (after(start_seq, tp->snd_una)) - return 1; + return true; if (!is_dsack || !tp->undo_marker) - return 0; + return false; /* ...Then it's D-SACK, and must reside below snd_una completely */ if (after(end_seq, tp->snd_una)) - return 0; + return false; if (!before(start_seq, tp->undo_marker)) - return 1; + return true; /* Too old */ if (!after(end_seq, tp->undo_marker)) - return 0; + return false; /* Undo_marker boundary crossing (overestimates a lot). Known already: * start_seq < undo_marker and end_seq >= undo_marker. @@ -1219,17 +1225,17 @@ static void tcp_mark_lost_retrans(struct sock *sk) tp->lost_retrans_low = new_low_seq; } -static int tcp_check_dsack(struct sock *sk, const struct sk_buff *ack_skb, - struct tcp_sack_block_wire *sp, int num_sacks, - u32 prior_snd_una) +static bool tcp_check_dsack(struct sock *sk, const struct sk_buff *ack_skb, + struct tcp_sack_block_wire *sp, int num_sacks, + u32 prior_snd_una) { struct tcp_sock *tp = tcp_sk(sk); u32 start_seq_0 = get_unaligned_be32(&sp[0].start_seq); u32 end_seq_0 = get_unaligned_be32(&sp[0].end_seq); - int dup_sack = 0; + bool dup_sack = false; if (before(start_seq_0, TCP_SKB_CB(ack_skb)->ack_seq)) { - dup_sack = 1; + dup_sack = true; tcp_dsack_seen(tp); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPDSACKRECV); } else if (num_sacks > 1) { @@ -1238,7 +1244,7 @@ static int tcp_check_dsack(struct sock *sk, const struct sk_buff *ack_skb, if (!after(end_seq_0, end_seq_1) && !before(start_seq_0, start_seq_1)) { - dup_sack = 1; + dup_sack = true; tcp_dsack_seen(tp); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPDSACKOFORECV); @@ -1269,9 +1275,10 @@ struct tcp_sacktag_state { * FIXME: this could be merged to shift decision code */ static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb, - u32 start_seq, u32 end_seq) + u32 start_seq, u32 end_seq) { - int in_sack, err; + int err; + bool in_sack; unsigned int pkt_len; unsigned int mss; @@ -1317,7 +1324,7 @@ static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb, static u8 tcp_sacktag_one(struct sock *sk, struct tcp_sacktag_state *state, u8 sacked, u32 start_seq, u32 end_seq, - int dup_sack, int pcount) + bool dup_sack, int pcount) { struct tcp_sock *tp = tcp_sk(sk); int fack_count = state->fack_count; @@ -1397,10 +1404,10 @@ 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 int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb, - struct tcp_sacktag_state *state, - unsigned int pcount, int shifted, int mss, - int dup_sack) +static bool tcp_shifted_skb(struct sock *sk, 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); @@ -1450,7 +1457,7 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb, if (skb->len > 0) { BUG_ON(!tcp_skb_pcount(skb)); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SACKSHIFTED); - return 0; + return false; } /* Whole SKB was eaten :-) */ @@ -1473,7 +1480,7 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb, NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SACKMERGED); - return 1; + return true; } /* I wish gso_size would have a bit more sane initialization than @@ -1496,7 +1503,7 @@ static int skb_can_shift(const struct sk_buff *skb) static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb, struct tcp_sacktag_state *state, u32 start_seq, u32 end_seq, - int dup_sack) + bool dup_sack) { struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *prev; @@ -1635,14 +1642,14 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk, struct tcp_sack_block *next_dup, struct tcp_sacktag_state *state, u32 start_seq, u32 end_seq, - int dup_sack_in) + bool dup_sack_in) { struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *tmp; tcp_for_write_queue_from(skb, sk) { int in_sack = 0; - int dup_sack = dup_sack_in; + bool dup_sack = dup_sack_in; if (skb == tcp_send_head(sk)) break; @@ -1657,7 +1664,7 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk, next_dup->start_seq, next_dup->end_seq); if (in_sack > 0) - dup_sack = 1; + dup_sack = true; } /* skb reference here is a bit tricky to get right, since @@ -1762,7 +1769,7 @@ tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb, struct sk_buff *skb; int num_sacks = min(TCP_NUM_SACKS, (ptr[1] - TCPOLEN_SACK_BASE) >> 3); int used_sacks; - int found_dup_sack = 0; + bool found_dup_sack = false; int i, j; int first_sack_index; @@ -1793,7 +1800,7 @@ tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb, used_sacks = 0; first_sack_index = 0; for (i = 0; i < num_sacks; i++) { - int dup_sack = !i && found_dup_sack; + bool dup_sack = !i && found_dup_sack; sp[used_sacks].start_seq = get_unaligned_be32(&sp_wire[i].start_seq); sp[used_sacks].end_seq = get_unaligned_be32(&sp_wire[i].end_seq); @@ -1860,7 +1867,7 @@ tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb, while (i < used_sacks) { u32 start_seq = sp[i].start_seq; u32 end_seq = sp[i].end_seq; - int dup_sack = (found_dup_sack && (i == first_sack_index)); + bool dup_sack = (found_dup_sack && (i == first_sack_index)); struct tcp_sack_block *next_dup = NULL; if (found_dup_sack && ((i + 1) == first_sack_index)) @@ -1962,9 +1969,9 @@ out: } /* Limits sacked_out so that sum with lost_out isn't ever larger than - * packets_out. Returns zero if sacked_out adjustement wasn't necessary. + * packets_out. Returns false if sacked_out adjustement wasn't necessary. */ -static int tcp_limit_reno_sacked(struct tcp_sock *tp) +static bool tcp_limit_reno_sacked(struct tcp_sock *tp) { u32 holes; @@ -1973,9 +1980,9 @@ static int tcp_limit_reno_sacked(struct tcp_sock *tp) if ((tp->sacked_out + holes) > tp->packets_out) { tp->sacked_out = tp->packets_out - holes; - return 1; + return true; } - return 0; + return false; } /* If we receive more dupacks than we expected counting segments @@ -2029,40 +2036,40 @@ static int tcp_is_sackfrto(const struct tcp_sock *tp) /* F-RTO can only be used if TCP has never retransmitted anything other than * head (SACK enhanced variant from Appendix B of RFC4138 is more robust here) */ -int tcp_use_frto(struct sock *sk) +bool tcp_use_frto(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); const struct inet_connection_sock *icsk = inet_csk(sk); struct sk_buff *skb; if (!sysctl_tcp_frto) - return 0; + return false; /* MTU probe and F-RTO won't really play nicely along currently */ if (icsk->icsk_mtup.probe_size) - return 0; + return false; if (tcp_is_sackfrto(tp)) - return 1; + return true; /* Avoid expensive walking of rexmit queue if possible */ if (tp->retrans_out > 1) - return 0; + return false; skb = tcp_write_queue_head(sk); if (tcp_skb_is_last(sk, skb)) - return 1; + return true; skb = tcp_write_queue_next(sk, skb); /* Skips head */ tcp_for_write_queue_from(skb, sk) { if (skb == tcp_send_head(sk)) break; if (TCP_SKB_CB(skb)->sacked & TCPCB_RETRANS) - return 0; + return false; /* Short-circuit when first non-SACKed skb has been checked */ if (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) break; } - return 1; + return true; } /* RTO occurred, but do not yet enter Loss state. Instead, defer RTO @@ -2298,7 +2305,7 @@ void tcp_enter_loss(struct sock *sk, int how) * * Do processing similar to RTO timeout. */ -static int tcp_check_sack_reneging(struct sock *sk, int flag) +static bool tcp_check_sack_reneging(struct sock *sk, int flag) { if (flag & FLAG_SACK_RENEGING) { struct inet_connection_sock *icsk = inet_csk(sk); @@ -2309,9 +2316,9 @@ static int tcp_check_sack_reneging(struct sock *sk, int flag) tcp_retransmit_skb(sk, tcp_write_queue_head(sk)); inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto, TCP_RTO_MAX); - return 1; + return true; } - return 0; + return false; } static inline int tcp_fackets_out(const struct tcp_sock *tp) @@ -2339,6 +2346,27 @@ static inline int tcp_dupack_heuristics(const struct tcp_sock *tp) return tcp_is_fack(tp) ? tp->fackets_out : tp->sacked_out + 1; } +static bool tcp_pause_early_retransmit(struct sock *sk, int flag) +{ + struct tcp_sock *tp = tcp_sk(sk); + unsigned long delay; + + /* Delay early retransmit and entering fast recovery for + * max(RTT/4, 2msec) unless ack has ECE mark, no RTT samples + * available, or RTO is scheduled to fire first. + */ + if (sysctl_tcp_early_retrans < 2 || (flag & FLAG_ECE) || !tp->srtt) + return false; + + delay = max_t(unsigned long, (tp->srtt >> 5), msecs_to_jiffies(2)); + if (!time_after(inet_csk(sk)->icsk_timeout, (jiffies + delay))) + return false; + + inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, delay, TCP_RTO_MAX); + tp->early_retrans_delayed = 1; + return true; +} + static inline int tcp_skb_timedout(const struct sock *sk, const struct sk_buff *skb) { @@ -2446,28 +2474,28 @@ static inline int tcp_head_timedout(const struct sock *sk) * Main question: may we further continue forward transmission * with the same cwnd? */ -static int tcp_time_to_recover(struct sock *sk) +static bool tcp_time_to_recover(struct sock *sk, int flag) { struct tcp_sock *tp = tcp_sk(sk); __u32 packets_out; /* Do not perform any recovery during F-RTO algorithm */ if (tp->frto_counter) - return 0; + return false; /* Trick#1: The loss is proven. */ if (tp->lost_out) - return 1; + return true; /* Not-A-Trick#2 : Classic rule... */ if (tcp_dupack_heuristics(tp) > tp->reordering) - return 1; + return true; /* Trick#3 : when we use RFC2988 timer restart, fast * retransmit can be triggered by timeout of queue head. */ if (tcp_is_fack(tp) && tcp_head_timedout(sk)) - return 1; + return true; /* Trick#4: It is still not OK... But will it be useful to delay * recovery more? @@ -2479,7 +2507,7 @@ static int tcp_time_to_recover(struct sock *sk) /* We have nothing to send. This connection is limited * either by receiver window or by application. */ - return 1; + return true; } /* If a thin stream is detected, retransmit after first @@ -2490,9 +2518,19 @@ static int tcp_time_to_recover(struct sock *sk) if ((tp->thin_dupack || sysctl_tcp_thin_dupack) && tcp_stream_is_thin(tp) && tcp_dupack_heuristics(tp) > 1 && tcp_is_sack(tp) && !tcp_send_head(sk)) - return 1; + return true; - return 0; + /* Trick#6: TCP early retransmit, per RFC5827. To avoid spurious + * retransmissions due to small network reorderings, we implement + * Mitigation A.3 in the RFC and delay the retransmission for a short + * interval if appropriate. + */ + if (tp->do_early_retrans && !tp->retrans_out && tp->sacked_out && + (tp->packets_out == (tp->sacked_out + 1) && tp->packets_out < 4) && + !tcp_may_send_now(sk)) + return !tcp_pause_early_retransmit(sk, flag); + + return false; } /* New heuristics: it is possible only after we switched to restart timer @@ -2680,22 +2718,22 @@ static void DBGUNDO(struct sock *sk, const char *msg) struct inet_sock *inet = inet_sk(sk); if (sk->sk_family == AF_INET) { - printk(KERN_DEBUG "Undo %s %pI4/%u c%u l%u ss%u/%u p%u\n", - msg, - &inet->inet_daddr, ntohs(inet->inet_dport), - tp->snd_cwnd, tcp_left_out(tp), - tp->snd_ssthresh, tp->prior_ssthresh, - tp->packets_out); + pr_debug("Undo %s %pI4/%u c%u l%u ss%u/%u p%u\n", + msg, + &inet->inet_daddr, ntohs(inet->inet_dport), + tp->snd_cwnd, tcp_left_out(tp), + tp->snd_ssthresh, tp->prior_ssthresh, + tp->packets_out); } #if IS_ENABLED(CONFIG_IPV6) else if (sk->sk_family == AF_INET6) { struct ipv6_pinfo *np = inet6_sk(sk); - printk(KERN_DEBUG "Undo %s %pI6/%u c%u l%u ss%u/%u p%u\n", - msg, - &np->daddr, ntohs(inet->inet_dport), - tp->snd_cwnd, tcp_left_out(tp), - tp->snd_ssthresh, tp->prior_ssthresh, - tp->packets_out); + pr_debug("Undo %s %pI6/%u c%u l%u ss%u/%u p%u\n", + msg, + &np->daddr, ntohs(inet->inet_dport), + tp->snd_cwnd, tcp_left_out(tp), + tp->snd_ssthresh, tp->prior_ssthresh, + tp->packets_out); } #endif } @@ -2731,7 +2769,7 @@ static inline int tcp_may_undo(const struct tcp_sock *tp) } /* People celebrate: "We love our President!" */ -static int tcp_try_undo_recovery(struct sock *sk) +static bool tcp_try_undo_recovery(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); @@ -2756,10 +2794,10 @@ static int tcp_try_undo_recovery(struct sock *sk) * is ACKed. For Reno it is MUST to prevent false * fast retransmits (RFC2582). SACK TCP is safe. */ tcp_moderate_cwnd(tp); - return 1; + return true; } tcp_set_ca_state(sk, TCP_CA_Open); - return 0; + return false; } /* Try to undo cwnd reduction, because D-SACKs acked all retransmitted data */ @@ -2789,19 +2827,19 @@ static void tcp_try_undo_dsack(struct sock *sk) * that successive retransmissions of a segment must not advance * retrans_stamp under any conditions. */ -static int tcp_any_retrans_done(const struct sock *sk) +static bool tcp_any_retrans_done(const struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; if (tp->retrans_out) - return 1; + return true; skb = tcp_write_queue_head(sk); if (unlikely(skb && TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS)) - return 1; + return true; - return 0; + return false; } /* Undo during fast recovery after partial ACK. */ @@ -2835,7 +2873,7 @@ static int tcp_try_undo_partial(struct sock *sk, int acked) } /* Undo during loss recovery after partial ACK. */ -static int tcp_try_undo_loss(struct sock *sk) +static bool tcp_try_undo_loss(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); @@ -2857,9 +2895,9 @@ static int tcp_try_undo_loss(struct sock *sk) tp->undo_marker = 0; if (tcp_is_sack(tp)) tcp_set_ca_state(sk, TCP_CA_Open); - return 1; + return true; } - return 0; + return false; } static inline void tcp_complete_cwr(struct sock *sk) @@ -3025,6 +3063,38 @@ static void tcp_update_cwnd_in_recovery(struct sock *sk, int newly_acked_sacked, tp->snd_cwnd = tcp_packets_in_flight(tp) + sndcnt; } +static void tcp_enter_recovery(struct sock *sk, bool ece_ack) +{ + struct tcp_sock *tp = tcp_sk(sk); + int mib_idx; + + if (tcp_is_reno(tp)) + mib_idx = LINUX_MIB_TCPRENORECOVERY; + else + mib_idx = LINUX_MIB_TCPSACKRECOVERY; + + NET_INC_STATS_BH(sock_net(sk), mib_idx); + + tp->high_seq = tp->snd_nxt; + tp->prior_ssthresh = 0; + tp->undo_marker = tp->snd_una; + tp->undo_retrans = tp->retrans_out; + + if (inet_csk(sk)->icsk_ca_state < TCP_CA_CWR) { + if (!ece_ack) + tp->prior_ssthresh = tcp_current_ssthresh(sk); + tp->snd_ssthresh = inet_csk(sk)->icsk_ca_ops->ssthresh(sk); + TCP_ECN_queue_cwr(tp); + } + + tp->bytes_acked = 0; + tp->snd_cwnd_cnt = 0; + tp->prior_cwnd = tp->snd_cwnd; + tp->prr_delivered = 0; + tp->prr_out = 0; + tcp_set_ca_state(sk, TCP_CA_Recovery); +} + /* 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 @@ -3044,7 +3114,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, struct tcp_sock *tp = tcp_sk(sk); int do_lost = is_dupack || ((flag & FLAG_DATA_SACKED) && (tcp_fackets_out(tp) > tp->reordering)); - int fast_rexmit = 0, mib_idx; + int fast_rexmit = 0; if (WARN_ON(!tp->packets_out && tp->sacked_out)) tp->sacked_out = 0; @@ -3128,7 +3198,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, if (icsk->icsk_ca_state <= TCP_CA_Disorder) tcp_try_undo_dsack(sk); - if (!tcp_time_to_recover(sk)) { + if (!tcp_time_to_recover(sk, flag)) { tcp_try_to_open(sk, flag); return; } @@ -3145,32 +3215,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, } /* Otherwise enter Recovery state */ - - if (tcp_is_reno(tp)) - mib_idx = LINUX_MIB_TCPRENORECOVERY; - else - mib_idx = LINUX_MIB_TCPSACKRECOVERY; - - NET_INC_STATS_BH(sock_net(sk), mib_idx); - - tp->high_seq = tp->snd_nxt; - tp->prior_ssthresh = 0; - tp->undo_marker = tp->snd_una; - tp->undo_retrans = tp->retrans_out; - - if (icsk->icsk_ca_state < TCP_CA_CWR) { - if (!(flag & FLAG_ECE)) - tp->prior_ssthresh = tcp_current_ssthresh(sk); - tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk); - TCP_ECN_queue_cwr(tp); - } - - tp->bytes_acked = 0; - tp->snd_cwnd_cnt = 0; - tp->prior_cwnd = tp->snd_cwnd; - tp->prr_delivered = 0; - tp->prr_out = 0; - tcp_set_ca_state(sk, TCP_CA_Recovery); + tcp_enter_recovery(sk, (flag & FLAG_ECE)); fast_rexmit = 1; } @@ -3252,16 +3297,47 @@ static void tcp_cong_avoid(struct sock *sk, u32 ack, u32 in_flight) /* Restart timer after forward progress on connection. * RFC2988 recommends to restart timer to now+rto. */ -static void tcp_rearm_rto(struct sock *sk) +void tcp_rearm_rto(struct sock *sk) { - const struct tcp_sock *tp = tcp_sk(sk); + struct tcp_sock *tp = tcp_sk(sk); if (!tp->packets_out) { inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); } else { - inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, - inet_csk(sk)->icsk_rto, TCP_RTO_MAX); + u32 rto = inet_csk(sk)->icsk_rto; + /* Offset the time elapsed after installing regular RTO */ + if (tp->early_retrans_delayed) { + struct sk_buff *skb = tcp_write_queue_head(sk); + const u32 rto_time_stamp = TCP_SKB_CB(skb)->when + rto; + s32 delta = (s32)(rto_time_stamp - tcp_time_stamp); + /* delta may not be positive if the socket is locked + * when the delayed ER timer fires and is rescheduled. + */ + if (delta > 0) + rto = delta; + } + inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, rto, + TCP_RTO_MAX); } + tp->early_retrans_delayed = 0; +} + +/* This function is called when the delayed ER timer fires. TCP enters + * fast recovery and performs fast-retransmit. + */ +void tcp_resume_early_retransmit(struct sock *sk) +{ + struct tcp_sock *tp = tcp_sk(sk); + + tcp_rearm_rto(sk); + + /* Stop if ER is disabled after the delayed ER timer is scheduled */ + if (!tp->do_early_retrans) + return; + + tcp_enter_recovery(sk, false); + tcp_update_scoreboard(sk, 1); + tcp_xmit_retransmit_queue(sk); } /* If we get here, the whole TSO packet has not been acked. */ @@ -3296,7 +3372,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets, const struct inet_connection_sock *icsk = inet_csk(sk); struct sk_buff *skb; u32 now = tcp_time_stamp; - int fully_acked = 1; + int fully_acked = true; int flag = 0; u32 pkts_acked = 0; u32 reord = tp->packets_out; @@ -3320,7 +3396,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets, if (!acked_pcount) break; - fully_acked = 0; + fully_acked = false; } else { acked_pcount = tcp_skb_pcount(skb); } @@ -3437,18 +3513,18 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets, if (!tp->packets_out && tcp_is_sack(tp)) { icsk = inet_csk(sk); if (tp->lost_out) { - printk(KERN_DEBUG "Leak l=%u %d\n", - tp->lost_out, icsk->icsk_ca_state); + pr_debug("Leak l=%u %d\n", + tp->lost_out, icsk->icsk_ca_state); tp->lost_out = 0; } if (tp->sacked_out) { - printk(KERN_DEBUG "Leak s=%u %d\n", - tp->sacked_out, icsk->icsk_ca_state); + pr_debug("Leak s=%u %d\n", + tp->sacked_out, icsk->icsk_ca_state); tp->sacked_out = 0; } if (tp->retrans_out) { - printk(KERN_DEBUG "Leak r=%u %d\n", - tp->retrans_out, icsk->icsk_ca_state); + pr_debug("Leak r=%u %d\n", + tp->retrans_out, icsk->icsk_ca_state); tp->retrans_out = 0; } } @@ -3599,7 +3675,7 @@ static void tcp_undo_spur_to_response(struct sock *sk, int flag) * to prove that the RTO is indeed spurious. It transfers the control * from F-RTO to the conventional RTO recovery */ -static int tcp_process_frto(struct sock *sk, int flag) +static bool tcp_process_frto(struct sock *sk, int flag) { struct tcp_sock *tp = tcp_sk(sk); @@ -3615,7 +3691,7 @@ static int tcp_process_frto(struct sock *sk, int flag) if (!before(tp->snd_una, tp->frto_highmark)) { tcp_enter_frto_loss(sk, (tp->frto_counter == 1 ? 2 : 3), flag); - return 1; + return true; } if (!tcp_is_sackfrto(tp)) { @@ -3624,19 +3700,19 @@ static int tcp_process_frto(struct sock *sk, int flag) * data, winupdate */ if (!(flag & FLAG_ANY_PROGRESS) && (flag & FLAG_NOT_DUP)) - return 1; + return true; if (!(flag & FLAG_DATA_ACKED)) { tcp_enter_frto_loss(sk, (tp->frto_counter == 1 ? 0 : 3), flag); - return 1; + return true; } } else { if (!(flag & FLAG_DATA_ACKED) && (tp->frto_counter == 1)) { /* Prevent sending of new data. */ tp->snd_cwnd = min(tp->snd_cwnd, tcp_packets_in_flight(tp)); - return 1; + return true; } if ((tp->frto_counter >= 2) && @@ -3646,10 +3722,10 @@ static int tcp_process_frto(struct sock *sk, int flag) /* RFC4138 shortcoming (see comment above) */ if (!(flag & FLAG_FORWARD_PROGRESS) && (flag & FLAG_NOT_DUP)) - return 1; + return true; tcp_enter_frto_loss(sk, 3, flag); - return 1; + return true; } } @@ -3661,7 +3737,7 @@ static int tcp_process_frto(struct sock *sk, int flag) if (!tcp_may_send_now(sk)) tcp_enter_frto_loss(sk, 2, flag); - return 1; + return true; } else { switch (sysctl_tcp_frto_response) { case 2: @@ -3678,7 +3754,7 @@ static int tcp_process_frto(struct sock *sk, int flag) tp->undo_marker = 0; NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSPURIOUSRTOS); } - return 0; + return false; } /* This routine deals with incoming acks, but not outgoing ones. */ @@ -3696,7 +3772,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) int prior_sacked = tp->sacked_out; int pkts_acked = 0; int newly_acked_sacked = 0; - int frto_cwnd = 0; + bool frto_cwnd = false; /* If the ack is older than previous acks * then we can probably ignore it. @@ -3710,6 +3786,9 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) if (after(ack, tp->snd_nxt)) goto invalid_ack; + if (tp->early_retrans_delayed) + tcp_rearm_rto(sk); + if (after(ack, prior_snd_una)) flag |= FLAG_SND_UNA_ADVANCED; @@ -3875,10 +3954,9 @@ void tcp_parse_options(const struct sk_buff *skb, struct tcp_options_received *o __u8 snd_wscale = *(__u8 *)ptr; opt_rx->wscale_ok = 1; if (snd_wscale > 14) { - if (net_ratelimit()) - pr_info("%s: Illegal window scaling value %d >14 received\n", - __func__, - snd_wscale); + net_info_ratelimited("%s: Illegal window scaling value %d >14 received\n", + __func__, + snd_wscale); snd_wscale = 14; } opt_rx->snd_wscale = snd_wscale; @@ -3949,7 +4027,7 @@ void tcp_parse_options(const struct sk_buff *skb, struct tcp_options_received *o } EXPORT_SYMBOL(tcp_parse_options); -static int tcp_parse_aligned_timestamp(struct tcp_sock *tp, const struct tcphdr *th) +static bool tcp_parse_aligned_timestamp(struct tcp_sock *tp, const struct tcphdr *th) { const __be32 *ptr = (const __be32 *)(th + 1); @@ -3960,31 +4038,31 @@ static int tcp_parse_aligned_timestamp(struct tcp_sock *tp, const struct tcphdr tp->rx_opt.rcv_tsval = ntohl(*ptr); ++ptr; tp->rx_opt.rcv_tsecr = ntohl(*ptr); - return 1; + return true; } - return 0; + return false; } /* Fast parse options. This hopes to only see timestamps. * If it is wrong it falls back on tcp_parse_options(). */ -static int tcp_fast_parse_options(const struct sk_buff *skb, - const struct tcphdr *th, - struct tcp_sock *tp, const u8 **hvpp) +static bool tcp_fast_parse_options(const struct sk_buff *skb, + const struct tcphdr *th, + struct tcp_sock *tp, const u8 **hvpp) { /* In the spirit of fast parsing, compare doff directly to constant * values. Because equality is used, short doff can be ignored here. */ if (th->doff == (sizeof(*th) / 4)) { tp->rx_opt.saw_tstamp = 0; - return 0; + return false; } else if (tp->rx_opt.tstamp_ok && th->doff == ((sizeof(*th) + TCPOLEN_TSTAMP_ALIGNED) / 4)) { if (tcp_parse_aligned_timestamp(tp, th)) - return 1; + return true; } tcp_parse_options(skb, &tp->rx_opt, hvpp, 1); - return 1; + return true; } #ifdef CONFIG_TCP_MD5SIG @@ -4225,7 +4303,7 @@ static void tcp_fin(struct sock *sk) } } -static inline int tcp_sack_extend(struct tcp_sack_block *sp, u32 seq, +static inline bool tcp_sack_extend(struct tcp_sack_block *sp, u32 seq, u32 end_seq) { if (!after(seq, sp->end_seq) && !after(sp->start_seq, end_seq)) { @@ -4233,9 +4311,9 @@ static inline int tcp_sack_extend(struct tcp_sack_block *sp, u32 seq, sp->start_seq = seq; if (after(end_seq, sp->end_seq)) sp->end_seq = end_seq; - return 1; + return true; } - return 0; + return false; } static void tcp_dsack_set(struct sock *sk, u32 seq, u32 end_seq) @@ -4431,10 +4509,10 @@ static void tcp_ofo_queue(struct sock *sk) } } -static int tcp_prune_ofo_queue(struct sock *sk); +static bool tcp_prune_ofo_queue(struct sock *sk); static int tcp_prune_queue(struct sock *sk); -static inline int tcp_try_rmem_schedule(struct sock *sk, unsigned int size) +static int tcp_try_rmem_schedule(struct sock *sk, unsigned int size) { if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || !sk_rmem_schedule(sk, size)) { @@ -4453,6 +4531,41 @@ static inline int tcp_try_rmem_schedule(struct sock *sk, unsigned int size) return 0; } +/** + * tcp_try_coalesce - try to merge skb to prior one + * @sk: socket + * @to: prior buffer + * @from: buffer to add in queue + * @fragstolen: pointer to boolean + * + * Before queueing skb @from after @to, try to merge them + * to reduce overall memory use and queue lengths, if cost is small. + * Packets in ofo or receive queues can stay a long time. + * Better try to coalesce them right now to avoid future collapses. + * Returns true if caller should free @from instead of queueing it + */ +static bool tcp_try_coalesce(struct sock *sk, + struct sk_buff *to, + struct sk_buff *from, + bool *fragstolen) +{ + int delta; + + *fragstolen = false; + + if (tcp_hdr(from)->fin) + return false; + if (!skb_try_coalesce(to, from, fragstolen, &delta)) + return false; + + atomic_add(delta, &sk->sk_rmem_alloc); + sk_mem_charge(sk, delta); + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPRCVCOALESCE); + TCP_SKB_CB(to)->end_seq = TCP_SKB_CB(from)->end_seq; + TCP_SKB_CB(to)->ack_seq = TCP_SKB_CB(from)->ack_seq; + return true; +} + static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) { struct tcp_sock *tp = tcp_sk(sk); @@ -4491,23 +4604,13 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) end_seq = TCP_SKB_CB(skb)->end_seq; if (seq == TCP_SKB_CB(skb1)->end_seq) { - /* Packets in ofo can stay in queue a long time. - * Better try to coalesce them right now - * to avoid future tcp_collapse_ofo_queue(), - * probably the most expensive function in tcp stack. - */ - if (skb->len <= skb_tailroom(skb1) && !tcp_hdr(skb)->fin) { - NET_INC_STATS_BH(sock_net(sk), - LINUX_MIB_TCPRCVCOALESCE); - BUG_ON(skb_copy_bits(skb, 0, - skb_put(skb1, skb->len), - skb->len)); - TCP_SKB_CB(skb1)->end_seq = end_seq; - TCP_SKB_CB(skb1)->ack_seq = TCP_SKB_CB(skb)->ack_seq; - __kfree_skb(skb); - skb = NULL; - } else { + bool fragstolen; + + if (!tcp_try_coalesce(sk, skb1, skb, &fragstolen)) { __skb_queue_after(&tp->out_of_order_queue, skb1, skb); + } else { + kfree_skb_partial(skb, fragstolen); + skb = NULL; } if (!tp->rx_opt.num_sacks || @@ -4583,12 +4686,65 @@ end: skb_set_owner_r(skb, sk); } +static int __must_check tcp_queue_rcv(struct sock *sk, struct sk_buff *skb, int hdrlen, + bool *fragstolen) +{ + int eaten; + struct sk_buff *tail = skb_peek_tail(&sk->sk_receive_queue); + + __skb_pull(skb, hdrlen); + eaten = (tail && + tcp_try_coalesce(sk, tail, skb, fragstolen)) ? 1 : 0; + tcp_sk(sk)->rcv_nxt = TCP_SKB_CB(skb)->end_seq; + if (!eaten) { + __skb_queue_tail(&sk->sk_receive_queue, skb); + skb_set_owner_r(skb, sk); + } + return eaten; +} + +int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size) +{ + struct sk_buff *skb; + struct tcphdr *th; + bool fragstolen; + + if (tcp_try_rmem_schedule(sk, size + sizeof(*th))) + goto err; + + skb = alloc_skb(size + sizeof(*th), sk->sk_allocation); + if (!skb) + goto err; + + th = (struct tcphdr *)skb_put(skb, sizeof(*th)); + skb_reset_transport_header(skb); + memset(th, 0, sizeof(*th)); + + if (memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size)) + goto err_free; + + TCP_SKB_CB(skb)->seq = tcp_sk(sk)->rcv_nxt; + TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq + size; + TCP_SKB_CB(skb)->ack_seq = tcp_sk(sk)->snd_una - 1; + + if (tcp_queue_rcv(sk, skb, sizeof(*th), &fragstolen)) { + WARN_ON_ONCE(fragstolen); /* should not happen */ + __kfree_skb(skb); + } + return size; + +err_free: + kfree_skb(skb); +err: + return -ENOMEM; +} static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) { const struct tcphdr *th = tcp_hdr(skb); struct tcp_sock *tp = tcp_sk(sk); int eaten = -1; + bool fragstolen = false; if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) goto drop; @@ -4633,8 +4789,7 @@ queue_and_out: tcp_try_rmem_schedule(sk, skb->truesize)) goto drop; - skb_set_owner_r(skb, sk); - __skb_queue_tail(&sk->sk_receive_queue, skb); + eaten = tcp_queue_rcv(sk, skb, 0, &fragstolen); } tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq; if (skb->len) @@ -4658,7 +4813,7 @@ queue_and_out: tcp_fast_path_check(sk); if (eaten > 0) - __kfree_skb(skb); + kfree_skb_partial(skb, fragstolen); else if (!sock_flag(sk, SOCK_DEAD)) sk->sk_data_ready(sk, 0); return; @@ -4878,10 +5033,10 @@ static void tcp_collapse_ofo_queue(struct sock *sk) * Purge the out-of-order queue. * Return true if queue was pruned. */ -static int tcp_prune_ofo_queue(struct sock *sk) +static bool tcp_prune_ofo_queue(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); - int res = 0; + bool res = false; if (!skb_queue_empty(&tp->out_of_order_queue)) { NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_OFOPRUNED); @@ -4895,7 +5050,7 @@ static int tcp_prune_ofo_queue(struct sock *sk) if (tp->rx_opt.sack_ok) tcp_sack_reset(&tp->rx_opt); sk_mem_reclaim(sk); - res = 1; + res = true; } return res; } @@ -4972,7 +5127,7 @@ void tcp_cwnd_application_limited(struct sock *sk) tp->snd_cwnd_stamp = tcp_time_stamp; } -static int tcp_should_expand_sndbuf(const struct sock *sk) +static bool tcp_should_expand_sndbuf(const struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); @@ -4980,21 +5135,21 @@ static int tcp_should_expand_sndbuf(const struct sock *sk) * not modify it. */ if (sk->sk_userlocks & SOCK_SNDBUF_LOCK) - return 0; + return false; /* If we are under global TCP memory pressure, do not expand. */ if (sk_under_memory_pressure(sk)) - return 0; + return false; /* If we are under soft global TCP memory pressure, do not expand. */ if (sk_memory_allocated(sk) >= sk_prot_mem_limits(sk, 0)) - return 0; + return false; /* If we filled the congestion window, do not expand. */ if (tp->packets_out >= tp->snd_cwnd) - return 0; + return false; - return 1; + return true; } /* When incoming ACK allowed to free some skb from write_queue, @@ -5220,16 +5375,16 @@ static inline int tcp_checksum_complete_user(struct sock *sk, } #ifdef CONFIG_NET_DMA -static int tcp_dma_try_early_copy(struct sock *sk, struct sk_buff *skb, +static bool tcp_dma_try_early_copy(struct sock *sk, struct sk_buff *skb, int hlen) { struct tcp_sock *tp = tcp_sk(sk); int chunk = skb->len - hlen; int dma_cookie; - int copied_early = 0; + bool copied_early = false; if (tp->ucopy.wakeup) - return 0; + return false; if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list) tp->ucopy.dma_chan = net_dma_find_channel(); @@ -5245,7 +5400,7 @@ static int tcp_dma_try_early_copy(struct sock *sk, struct sk_buff *skb, goto out; tp->ucopy.dma_cookie = dma_cookie; - copied_early = 1; + copied_early = true; tp->ucopy.len -= chunk; tp->copied_seq += chunk; @@ -5437,6 +5592,7 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb, } else { int eaten = 0; int copied_early = 0; + bool fragstolen = false; if (tp->copied_seq == tp->rcv_nxt && len - tcp_header_len <= tp->ucopy.len) { @@ -5494,10 +5650,8 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb, NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPHPHITS); /* Bulk data transfer: receiver */ - __skb_pull(skb, tcp_header_len); - __skb_queue_tail(&sk->sk_receive_queue, skb); - skb_set_owner_r(skb, sk); - tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq; + eaten = tcp_queue_rcv(sk, skb, tcp_header_len, + &fragstolen); } tcp_event_data_recv(sk, skb); @@ -5519,7 +5673,7 @@ no_ack: else #endif if (eaten) - __kfree_skb(skb); + kfree_skb_partial(skb, fragstolen); else sk->sk_data_ready(sk, 0); return 0; @@ -5563,6 +5717,44 @@ discard: } EXPORT_SYMBOL(tcp_rcv_established); +void tcp_finish_connect(struct sock *sk, struct sk_buff *skb) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct inet_connection_sock *icsk = inet_csk(sk); + + tcp_set_state(sk, TCP_ESTABLISHED); + + if (skb != NULL) + security_inet_conn_established(sk, skb); + + /* Make sure socket is routed, for correct metrics. */ + icsk->icsk_af_ops->rebuild_header(sk); + + tcp_init_metrics(sk); + + tcp_init_congestion_control(sk); + + /* Prevent spurious tcp_cwnd_restart() on first data + * packet. + */ + tp->lsndtime = tcp_time_stamp; + + tcp_init_buffer_space(sk); + + if (sock_flag(sk, SOCK_KEEPOPEN)) + inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tp)); + + if (!tp->rx_opt.snd_wscale) + __tcp_fast_path_on(tp, tp->snd_wnd); + else + tp->pred_flags = 0; + + if (!sock_flag(sk, SOCK_DEAD)) { + sk->sk_state_change(sk); + sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); + } +} + static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, const struct tcphdr *th, unsigned int len) { @@ -5695,36 +5887,8 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, } smp_mb(); - tcp_set_state(sk, TCP_ESTABLISHED); - - security_inet_conn_established(sk, skb); - - /* Make sure socket is routed, for correct metrics. */ - icsk->icsk_af_ops->rebuild_header(sk); - - tcp_init_metrics(sk); - tcp_init_congestion_control(sk); - - /* Prevent spurious tcp_cwnd_restart() on first data - * packet. - */ - tp->lsndtime = tcp_time_stamp; - - tcp_init_buffer_space(sk); - - if (sock_flag(sk, SOCK_KEEPOPEN)) - inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tp)); - - if (!tp->rx_opt.snd_wscale) - __tcp_fast_path_on(tp, tp->snd_wnd); - else - tp->pred_flags = 0; - - if (!sock_flag(sk, SOCK_DEAD)) { - sk->sk_state_change(sk); - sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); - } + tcp_finish_connect(sk, skb); if (sk->sk_write_pending || icsk->icsk_accept_queue.rskq_defer_accept || @@ -5738,8 +5902,6 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, */ inet_csk_schedule_ack(sk); icsk->icsk_ack.lrcvtime = tcp_time_stamp; - icsk->icsk_ack.ato = TCP_ATO_MIN; - tcp_incr_quickack(sk); tcp_enter_quickack_mode(sk); inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, TCP_DELACK_MAX, TCP_RTO_MAX); |