#define pr_fmt(fmt) "TCP: " fmt #include #include #include #include #include #include #include #include #include #include #include int sysctl_tcp_timestamps __read_mostly = 1; 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; EXPORT_SYMBOL(sysctl_tcp_reordering); int sysctl_tcp_ecn __read_mostly = 2; EXPORT_SYMBOL(sysctl_tcp_ecn); 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); 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_frto_response __read_mostly; int sysctl_tcp_nometrics_save __read_mostly; int sysctl_tcp_thin_dupack __read_mostly; int sysctl_tcp_moderate_rcvbuf __read_mostly = 1; int sysctl_tcp_abc __read_mostly; #define FLAG_DATA 0x01 #define FLAG_WIN_UPDATE 0x02 #define FLAG_DATA_ACKED 0x04 #define FLAG_RETRANS_DATA_ACKED 0x08 #define FLAG_SYN_ACKED 0x10 #define FLAG_DATA_SACKED 0x20 #define FLAG_ECE 0x40 #define FLAG_SLOWPATH 0x100 #define FLAG_ONLY_ORIG_SACKED 0x200 #define FLAG_SND_UNA_ADVANCED 0x400 #define FLAG_DSACKING_ACK 0x800 #define FLAG_NONHEAD_RETRANS_ACKED 0x1000 #define FLAG_SACK_RENEGING 0x2000 #define FLAG_ACKED (FLAG_DATA_ACKED|FLAG_SYN_ACKED) #define FLAG_NOT_DUP (FLAG_DATA|FLAG_WIN_UPDATE|FLAG_ACKED) #define FLAG_CA_ALERT (FLAG_DATA_SACKED|FLAG_ECE) #define FLAG_FORWARD_PROGRESS (FLAG_ACKED|FLAG_DATA_SACKED) #define FLAG_ANY_PROGRESS (FLAG_FORWARD_PROGRESS|FLAG_SND_UNA_ADVANCED) #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)) 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; unsigned int len; icsk->icsk_ack.last_seg_size = 0; len = skb_shinfo(skb)->gso_size ? : skb->len; if (len >= icsk->icsk_ack.rcv_mss) { icsk->icsk_ack.rcv_mss = len; } else { len += skb->data - skb_transport_header(skb); if (len >= TCP_MSS_DEFAULT + sizeof(struct tcphdr) || (len >= TCP_MIN_MSS + sizeof(struct tcphdr) && !(tcp_flag_word(tcp_hdr(skb)) & TCP_REMNANT))) { len -= tcp_sk(sk)->tcp_header_len; icsk->icsk_ack.last_seg_size = len; if (len == lss) { icsk->icsk_ack.rcv_mss = len; return; } } if (icsk->icsk_ack.pending & ICSK_ACK_PUSHED) icsk->icsk_ack.pending |= ICSK_ACK_PUSHED2; icsk->icsk_ack.pending |= ICSK_ACK_PUSHED; } } 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); if (quickacks == 0) quickacks = 2; if (quickacks > icsk->icsk_ack.quick) icsk->icsk_ack.quick = min(quickacks, TCP_MAX_QUICKACKS); } static void tcp_enter_quickack_mode(struct sock *sk) { struct inet_connection_sock *icsk = inet_csk(sk); tcp_incr_quickack(sk); icsk->icsk_ack.pingpong = 0; icsk->icsk_ack.ato = TCP_ATO_MIN; } static inline int 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; } static inline void TCP_ECN_queue_cwr(struct tcp_sock *tp) { if (tp->ecn_flags & TCP_ECN_OK) tp->ecn_flags |= TCP_ECN_QUEUE_CWR; } static inline void TCP_ECN_accept_cwr(struct tcp_sock *tp, const struct sk_buff *skb) { if (tcp_hdr(skb)->cwr) tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR; } static inline void TCP_ECN_withdraw_cwr(struct tcp_sock *tp) { tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR; } static inline void TCP_ECN_check_ce(struct tcp_sock *tp, const struct sk_buff *skb) { if (!(tp->ecn_flags & TCP_ECN_OK)) return; switch (TCP_SKB_CB(skb)->ip_dsfield & INET_ECN_MASK) { case INET_ECN_NOT_ECT: if (tp->ecn_flags & TCP_ECN_SEEN) tcp_enter_quickack_mode((struct sock *)tp); break; case INET_ECN_CE: tp->ecn_flags |= TCP_ECN_DEMAND_CWR; default: tp->ecn_flags |= TCP_ECN_SEEN; } } static inline void TCP_ECN_rcv_synack(struct tcp_sock *tp, const struct tcphdr *th) { if ((tp->ecn_flags & TCP_ECN_OK) && (!th->ece || th->cwr)) tp->ecn_flags &= ~TCP_ECN_OK; } static inline void TCP_ECN_rcv_syn(struct tcp_sock *tp, const struct tcphdr *th) { if ((tp->ecn_flags & TCP_ECN_OK) && (!th->ece || !th->cwr)) tp->ecn_flags &= ~TCP_ECN_OK; } static inline int 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; } static void tcp_fixup_sndbuf(struct sock *sk) { int sndmem = SKB_TRUESIZE(tcp_sk(sk)->rx_opt.mss_clamp + MAX_TCP_HEADER); sndmem *= TCP_INIT_CWND; if (sk->sk_sndbuf < sndmem) sk->sk_sndbuf = min(sndmem, sysctl_tcp_wmem[2]); } static int __tcp_grow_window(const struct sock *sk, const struct sk_buff *skb) { struct tcp_sock *tp = tcp_sk(sk); int truesize = tcp_win_from_space(skb->truesize) >> 1; int window = tcp_win_from_space(sysctl_tcp_rmem[2]) >> 1; while (tp->rcv_ssthresh <= window) { if (truesize <= skb->len) return 2 * inet_csk(sk)->icsk_ack.rcv_mss; truesize >>= 1; window >>= 1; } return 0; } static void tcp_grow_window(struct sock *sk, const struct sk_buff *skb) { struct tcp_sock *tp = tcp_sk(sk); if (tp->rcv_ssthresh < tp->window_clamp && (int)tp->rcv_ssthresh < tcp_space(sk) && !sk_under_memory_pressure(sk)) { int incr; if (tcp_win_from_space(skb->truesize) <= skb->len) incr = 2 * tp->advmss; else incr = __tcp_grow_window(sk, skb); if (incr) { incr = max_t(int, incr, 2 * skb->len); tp->rcv_ssthresh = min(tp->rcv_ssthresh + incr, tp->window_clamp); inet_csk(sk)->icsk_ack.quick |= 1; } } } static void tcp_fixup_rcvbuf(struct sock *sk) { u32 mss = tcp_sk(sk)->advmss; u32 icwnd = TCP_DEFAULT_INIT_RCVWND; int rcvmem; if (mss > 1460) icwnd = max_t(u32, (1460 * TCP_DEFAULT_INIT_RCVWND) / mss, 2); rcvmem = SKB_TRUESIZE(mss + MAX_TCP_HEADER); while (tcp_win_from_space(rcvmem) < mss) rcvmem += 128; rcvmem *= icwnd; if (sk->sk_rcvbuf < rcvmem) sk->sk_rcvbuf = min(rcvmem, sysctl_tcp_rmem[2]); } static void tcp_init_buffer_space(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); int maxwin; if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) tcp_fixup_rcvbuf(sk); if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK)) tcp_fixup_sndbuf(sk); tp->rcvq_space.space = tp->rcv_wnd; maxwin = tcp_full_space(sk); if (tp->window_clamp >= maxwin) { tp->window_clamp = maxwin; if (sysctl_tcp_app_win && maxwin > 4 * tp->advmss) tp->window_clamp = max(maxwin - (maxwin >> sysctl_tcp_app_win), 4 * tp->advmss); } if (sysctl_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); tp->rcv_ssthresh = min(tp->rcv_ssthresh, tp->window_clamp); tp->snd_cwnd_stamp = tcp_time_stamp; } static void tcp_clamp_window(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); struct inet_connection_sock *icsk = inet_csk(sk); icsk->icsk_ack.quick = 0; if (sk->sk_rcvbuf < sysctl_tcp_rmem[2] && !(sk->sk_userlocks & SOCK_RCVBUF_LOCK) && !sk_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]); } if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) tp->rcv_ssthresh = min(tp->window_clamp, 2U * tp->advmss); } void tcp_initialize_rcv_mss(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); unsigned int hint = min_t(unsigned int, tp->advmss, tp->mss_cache); hint = min(hint, tp->rcv_wnd / 2); hint = min(hint, TCP_MSS_DEFAULT); hint = max(hint, TCP_MIN_MSS); inet_csk(sk)->icsk_ack.rcv_mss = hint; } EXPORT_SYMBOL(tcp_initialize_rcv_mss); static void tcp_rcv_rtt_update(struct tcp_sock *tp, u32 sample, int win_dep) { u32 new_sample = tp->rcv_rtt_est.rtt; long m = sample; if (m == 0) m = 1; if (new_sample != 0) { if (!win_dep) { m -= (new_sample >> 3); new_sample += m; } else { m <<= 3; if (m < new_sample) new_sample = m; } } else { new_sample = m << 3; } if (tp->rcv_rtt_est.rtt != new_sample) tp->rcv_rtt_est.rtt = new_sample; } static inline void tcp_rcv_rtt_measure(struct tcp_sock *tp) { if (tp->rcv_rtt_est.time == 0) goto new_measure; if (before(tp->rcv_nxt, tp->rcv_rtt_est.seq)) return; tcp_rcv_rtt_update(tp, tcp_time_stamp - tp->rcv_rtt_est.time, 1); new_measure: tp->rcv_rtt_est.seq = tp->rcv_nxt + tp->rcv_wnd; tp->rcv_rtt_est.time = tcp_time_stamp; } static inline void tcp_rcv_rtt_measure_ts(struct sock *sk, const struct sk_buff *skb) { struct tcp_sock *tp = tcp_sk(sk); if (tp->rx_opt.rcv_tsecr && (TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq >= inet_csk(sk)->icsk_ack.rcv_mss)) tcp_rcv_rtt_update(tp, tcp_time_stamp - tp->rx_opt.rcv_tsecr, 0); } 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); if (tp->rcvq_space.space != space) { int rcvmem; tp->rcvq_space.space = space; if (sysctl_tcp_moderate_rcvbuf && !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { int new_clamp = space; space /= tp->advmss; if (!space) space = 1; rcvmem = SKB_TRUESIZE(tp->advmss + MAX_TCP_HEADER); while (tcp_win_from_space(rcvmem) < tp->advmss) rcvmem += 128; space *= rcvmem; space = min(space, sysctl_tcp_rmem[2]); if (space > sk->sk_rcvbuf) { sk->sk_rcvbuf = space; tp->window_clamp = new_clamp; } } } new_measure: tp->rcvq_space.seq = tp->copied_seq; tp->rcvq_space.time = tcp_time_stamp; } static void tcp_event_data_recv(struct sock *sk, struct sk_buff *skb) { struct tcp_sock *tp = tcp_sk(sk); struct inet_connection_sock *icsk = inet_csk(sk); u32 now; inet_csk_schedule_ack(sk); tcp_measure_rcv_mss(sk, skb); tcp_rcv_rtt_measure(tp); now = tcp_time_stamp; if (!icsk->icsk_ack.ato) { tcp_incr_quickack(sk); icsk->icsk_ack.ato = TCP_ATO_MIN; } else { int m = now - icsk->icsk_ack.lrcvtime; if (m <= TCP_ATO_MIN / 2) { icsk->icsk_ack.ato = (icsk->icsk_ack.ato >> 1) + TCP_ATO_MIN / 2; } else if (m < icsk->icsk_ack.ato) { icsk->icsk_ack.ato = (icsk->icsk_ack.ato >> 1) + m; if (icsk->icsk_ack.ato > icsk->icsk_rto) icsk->icsk_ack.ato = icsk->icsk_rto; } else if (m > icsk->icsk_rto) { tcp_incr_quickack(sk); sk_mem_reclaim(sk); } } icsk->icsk_ack.lrcvtime = now; TCP_ECN_check_ce(tp, skb); if (skb->len >= 128) tcp_grow_window(sk, skb); } static void tcp_rtt_estimator(struct sock *sk, const __u32 mrtt) { struct tcp_sock *tp = tcp_sk(sk); long m = mrtt; if (m == 0) m = 1; if (tp->srtt != 0) { m -= (tp->srtt >> 3); tp->srtt += m; if (m < 0) { m = -m; m -= (tp->mdev >> 2); if (m > 0) m >>= 3; } else { m -= (tp->mdev >> 2); } tp->mdev += m; if (tp->mdev > tp->mdev_max) { tp->mdev_max = tp->mdev; if (tp->mdev_max > tp->rttvar) tp->rttvar = tp->mdev_max; } if (after(tp->snd_una, tp->rtt_seq)) { if (tp->mdev_max < tp->rttvar) tp->rttvar -= (tp->rttvar - tp->mdev_max) >> 2; tp->rtt_seq = tp->snd_nxt; tp->mdev_max = tcp_rto_min(sk); } } else { tp->srtt = m << 3; tp->mdev = m << 1; tp->mdev_max = tp->rttvar = max(tp->mdev, tcp_rto_min(sk)); tp->rtt_seq = tp->snd_nxt; } } static inline void tcp_set_rto(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); inet_csk(sk)->icsk_rto = __tcp_set_rto(tp); tcp_bound_rto(sk); } void tcp_update_metrics(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); struct dst_entry *dst = __sk_dst_get(sk); if (sysctl_tcp_nometrics_save) return; dst_confirm(dst); if (dst && (dst->flags & DST_HOST)) { const struct inet_connection_sock *icsk = inet_csk(sk); int m; unsigned long rtt; if (icsk->icsk_backoff || !tp->srtt) { if (!(dst_metric_locked(dst, RTAX_RTT))) dst_metric_set(dst, RTAX_RTT, 0); return; } rtt = dst_metric_rtt(dst, RTAX_RTT); m = rtt - tp->srtt; if (!(dst_metric_locked(dst, RTAX_RTT))) { if (m <= 0) set_dst_metric_rtt(dst, RTAX_RTT, tp->srtt); else set_dst_metric_rtt(dst, RTAX_RTT, rtt - (m >> 3)); } if (!(dst_metric_locked(dst, RTAX_RTTVAR))) { unsigned long var; if (m < 0) m = -m; m >>= 1; if (m < tp->mdev) m = tp->mdev; var = dst_metric_rtt(dst, RTAX_RTTVAR); if (m >= var) var = m; else var -= (var - m) >> 2; set_dst_metric_rtt(dst, RTAX_RTTVAR, var); } if (tcp_in_initial_slowstart(tp)) { if (dst_metric(dst, RTAX_SSTHRESH) && !dst_metric_locked(dst, RTAX_SSTHRESH) && (tp->snd_cwnd >> 1) > dst_metric(dst, RTAX_SSTHRESH)) dst_metric_set(dst, RTAX_SSTHRESH, tp->snd_cwnd >> 1); if (!dst_metric_locked(dst, RTAX_CWND) && tp->snd_cwnd > dst_metric(dst, RTAX_CWND)) dst_metric_set(dst, RTAX_CWND, tp->snd_cwnd); } else if (tp->snd_cwnd > tp->snd_ssthresh && icsk->icsk_ca_state == TCP_CA_Open) { if (!dst_metric_locked(dst, RTAX_SSTHRESH)) dst_metric_set(dst, RTAX_SSTHRESH, max(tp->snd_cwnd >> 1, tp->snd_ssthresh)); if (!dst_metric_locked(dst, RTAX_CWND)) dst_metric_set(dst, RTAX_CWND, (dst_metric(dst, RTAX_CWND) + tp->snd_cwnd) >> 1); } else { if (!dst_metric_locked(dst, RTAX_CWND)) dst_metric_set(dst, RTAX_CWND, (dst_metric(dst, RTAX_CWND) + tp->snd_ssthresh) >> 1); if (dst_metric(dst, RTAX_SSTHRESH) && !dst_metric_locked(dst, RTAX_SSTHRESH) && tp->snd_ssthresh > dst_metric(dst, RTAX_SSTHRESH)) dst_metric_set(dst, RTAX_SSTHRESH, tp->snd_ssthresh); } if (!dst_metric_locked(dst, RTAX_REORDERING)) { if (dst_metric(dst, RTAX_REORDERING) < tp->reordering && tp->reordering != sysctl_tcp_reordering) dst_metric_set(dst, RTAX_REORDERING, tp->reordering); } } } __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst) { __u32 cwnd = (dst ? dst_metric(dst, RTAX_INITCWND) : 0); if (!cwnd) cwnd = TCP_INIT_CWND; return min_t(__u32, cwnd, tp->snd_cwnd_clamp); } void tcp_enter_cwr(struct sock *sk, const int set_ssthresh) { struct tcp_sock *tp = tcp_sk(sk); const struct inet_connection_sock *icsk = inet_csk(sk); tp->prior_ssthresh = 0; tp->bytes_acked = 0; if (icsk->icsk_ca_state < TCP_CA_CWR) { tp->undo_marker = 0; if (set_ssthresh) tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk); tp->snd_cwnd = min(tp->snd_cwnd, tcp_packets_in_flight(tp) + 1U); tp->snd_cwnd_cnt = 0; tp->high_seq = tp->snd_nxt; tp->snd_cwnd_stamp = tcp_time_stamp; TCP_ECN_queue_cwr(tp); tcp_set_ca_state(sk, TCP_CA_CWR); } } static void tcp_disable_fack(struct tcp_sock *tp) { if (tcp_is_fack(tp)) tp->lost_skb_hint = NULL; tp->rx_opt.sack_ok &= ~TCP_FACK_ENABLED; } static void tcp_dsack_seen(struct tcp_sock *tp) { tp->rx_opt.sack_ok |= TCP_DSACK_SEEN; } static void tcp_init_metrics(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); struct dst_entry *dst = __sk_dst_get(sk); if (dst == NULL) goto reset; dst_confirm(dst); if (dst_metric_locked(dst, RTAX_CWND)) tp->snd_cwnd_clamp = dst_metric(dst, RTAX_CWND); if (dst_metric(dst, RTAX_SSTHRESH)) { tp->snd_ssthresh = dst_metric(dst, RTAX_SSTHRESH); if (tp->snd_ssthresh > tp->snd_cwnd_clamp) tp->snd_ssthresh = tp->snd_cwnd_clamp; } else { tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; } if (dst_metric(dst, RTAX_REORDERING) && tp->reordering != dst_metric(dst, RTAX_REORDERING)) { tcp_disable_fack(tp); tp->reordering = dst_metric(dst, RTAX_REORDERING); } if (dst_metric(dst, RTAX_RTT) == 0 || tp->srtt == 0) goto reset; if (dst_metric_rtt(dst, RTAX_RTT) > tp->srtt) { tp->srtt = dst_metric_rtt(dst, RTAX_RTT); tp->rtt_seq = tp->snd_nxt; } if (dst_metric_rtt(dst, RTAX_RTTVAR) > tp->mdev) { tp->mdev = dst_metric_rtt(dst, RTAX_RTTVAR); tp->mdev_max = tp->rttvar = max(tp->mdev, tcp_rto_min(sk)); } tcp_set_rto(sk); reset: if (tp->srtt == 0) { tp->mdev = tp->mdev_max = tp->rttvar = TCP_TIMEOUT_FALLBACK; inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK; } if (tp->total_retrans > 1) tp->snd_cwnd = 1; else tp->snd_cwnd = tcp_init_cwnd(tp, dst); tp->snd_cwnd_stamp = tcp_time_stamp; } static void tcp_update_reordering(struct sock *sk, const int metric, const int ts) { struct tcp_sock *tp = tcp_sk(sk); if (metric > tp->reordering) { int mib_idx; tp->reordering = min(TCP_MAX_REORDERING, metric); 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_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); #endif tcp_disable_fack(tp); } } static void tcp_verify_retransmit_hint(struct tcp_sock *tp, struct sk_buff *skb) { if ((tp->retransmit_skb_hint == NULL) || before(TCP_SKB_CB(skb)->seq, TCP_SKB_CB(tp->retransmit_skb_hint)->seq)) tp->retransmit_skb_hint = skb; if (!tp->lost_out || after(TCP_SKB_CB(skb)->end_seq, tp->retransmit_high)) tp->retransmit_high = TCP_SKB_CB(skb)->end_seq; } static void tcp_skb_mark_lost(struct tcp_sock *tp, struct sk_buff *skb) { if (!(TCP_SKB_CB(skb)->sacked & (TCPCB_LOST|TCPCB_SACKED_ACKED))) { tcp_verify_retransmit_hint(tp, skb); tp->lost_out += tcp_skb_pcount(skb); TCP_SKB_CB(skb)->sacked |= TCPCB_LOST; } } static void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, struct sk_buff *skb) { tcp_verify_retransmit_hint(tp, skb); if (!(TCP_SKB_CB(skb)->sacked & (TCPCB_LOST|TCPCB_SACKED_ACKED))) { tp->lost_out += tcp_skb_pcount(skb); TCP_SKB_CB(skb)->sacked |= TCPCB_LOST; } } static int tcp_is_sackblock_valid(struct tcp_sock *tp, int is_dsack, u32 start_seq, u32 end_seq) { if (after(end_seq, tp->snd_nxt) || !before(start_seq, end_seq)) return 0; if (!before(start_seq, tp->snd_nxt)) return 0; if (after(start_seq, tp->snd_una)) return 1; if (!is_dsack || !tp->undo_marker) return 0; if (after(end_seq, tp->snd_una)) return 0; if (!before(start_seq, tp->undo_marker)) return 1; if (!after(end_seq, tp->undo_marker)) return 0; return !before(start_seq, end_seq - tp->max_window); } static void tcp_mark_lost_retrans(struct sock *sk) { const struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; int cnt = 0; u32 new_low_seq = tp->snd_nxt; u32 received_upto = tcp_highest_sack_seq(tp); if (!tcp_is_fack(tp) || !tp->retrans_out || !after(received_upto, tp->lost_retrans_low) || icsk->icsk_ca_state != TCP_CA_Recovery) return; tcp_for_write_queue(skb, sk) { u32 ack_seq = TCP_SKB_CB(skb)->ack_seq; if (skb == tcp_send_head(sk)) break; if (cnt == tp->retrans_out) break; if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una)) continue; if (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS)) continue; if (after(received_upto, ack_seq)) { TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS; tp->retrans_out -= tcp_skb_pcount(skb); tcp_skb_mark_lost_uncond_verify(tp, skb); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPLOSTRETRANSMIT); } else { if (before(ack_seq, new_low_seq)) new_low_seq = ack_seq; cnt += tcp_skb_pcount(skb); } } if (tp->retrans_out) 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) { 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; if (before(start_seq_0, TCP_SKB_CB(ack_skb)->ack_seq)) { dup_sack = 1; tcp_dsack_seen(tp); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPDSACKRECV); } else if (num_sacks > 1) { u32 end_seq_1 = get_unaligned_be32(&sp[1].end_seq); u32 start_seq_1 = get_unaligned_be32(&sp[1].start_seq); if (!after(end_seq_0, end_seq_1) && !before(start_seq_0, start_seq_1)) { dup_sack = 1; tcp_dsack_seen(tp); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPDSACKOFORECV); } } /* D-SACK for already forgotten data... Do dumb counting. */ if (dup_sack && tp->undo_marker && tp->undo_retrans > 0 && !after(end_seq_0, prior_snd_una) && after(end_seq_0, tp->undo_marker)) tp->undo_retrans--; return dup_sack; } struct tcp_sacktag_state { int reord; int fack_count; int flag; }; static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb, u32 start_seq, u32 end_seq) { int in_sack, err; unsigned int pkt_len; unsigned int mss; in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq) && !before(end_seq, TCP_SKB_CB(skb)->end_seq); if (tcp_skb_pcount(skb) > 1 && !in_sack && after(TCP_SKB_CB(skb)->end_seq, start_seq)) { mss = tcp_skb_mss(skb); in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq); if (!in_sack) { pkt_len = start_seq - TCP_SKB_CB(skb)->seq; if (pkt_len < mss) pkt_len = mss; } else { pkt_len = end_seq - TCP_SKB_CB(skb)->seq; if (pkt_len < mss) return -EINVAL; } if (pkt_len > mss) { unsigned int new_len = (pkt_len / mss) * mss; if (!in_sack && new_len < pkt_len) { new_len += mss; if (new_len >= skb->len) return 0; } pkt_len = new_len; } err = tcp_fragment(sk, skb, pkt_len, mss); if (err < 0) return err; } return in_sack; } 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) { struct tcp_sock *tp = tcp_sk(sk); int fack_count = state->fack_count; 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 (!after(end_seq, tp->snd_una)) return sacked; if (!(sacked & TCPCB_SACKED_ACKED)) { if (sacked & TCPCB_SACKED_RETRANS) { if (sacked & TCPCB_LOST) { sacked &= ~(TCPCB_LOST|TCPCB_SACKED_RETRANS); tp->lost_out -= pcount; tp->retrans_out -= pcount; } } else { if (!(sacked & TCPCB_RETRANS)) { if (before(start_seq, tcp_highest_sack_seq(tp))) state->reord = min(fack_count, state->reord); if (!after(end_seq, tp->frto_highmark)) state->flag |= FLAG_ONLY_ORIG_SACKED; } if (sacked & TCPCB_LOST) { sacked &= ~TCPCB_LOST; tp->lost_out -= pcount; } } sacked |= TCPCB_SACKED_ACKED; state->flag |= FLAG_DATA_SACKED; tp->sacked_out += pcount; fack_count += pcount; if (!tcp_is_fack(tp) && (tp->lost_skb_hint != NULL) && 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; } if (dup_sack && (sacked & TCPCB_SACKED_RETRANS)) { sacked &= ~TCPCB_SACKED_RETRANS; tp->retrans_out -= pcount; } return sacked; } 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) { 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; u32 end_seq = start_seq + shifted; BUG_ON(!pcount); tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked, start_seq, end_seq, dup_sack, pcount); if (skb == tp->lost_skb_hint) tp->lost_cnt_hint += pcount; TCP_SKB_CB(prev)->end_seq += shifted; TCP_SKB_CB(skb)->seq += shifted; skb_shinfo(prev)->gso_segs += pcount; BUG_ON(skb_shinfo(skb)->gso_segs < pcount); skb_shinfo(skb)->gso_segs -= pcount; if (!skb_shinfo(prev)->gso_size) { skb_shinfo(prev)->gso_size = mss; skb_shinfo(prev)->gso_type = sk->sk_gso_type; } if (skb_shinfo(skb)->gso_segs <= 1) { skb_shinfo(skb)->gso_size = 0; skb_shinfo(skb)->gso_type = 0; } TCP_SKB_CB(prev)->sacked |= (TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS); if (skb->len > 0) { BUG_ON(!tcp_skb_pcount(skb)); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SACKSHIFTED); return 0; } if (skb == tp->retransmit_skb_hint) tp->retransmit_skb_hint = prev; if (skb == tp->scoreboard_skb_hint) tp->scoreboard_skb_hint = prev; if (skb == tp->lost_skb_hint) { tp->lost_skb_hint = prev; tp->lost_cnt_hint -= tcp_skb_pcount(prev); } TCP_SKB_CB(skb)->tcp_flags |= TCP_SKB_CB(prev)->tcp_flags; if (skb == tcp_highest_sack(sk)) tcp_advance_highest_sack(sk, skb); tcp_unlink_write_queue(skb, sk); sk_wmem_free_skb(sk, skb); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SACKMERGED); return 1; } static int tcp_skb_seglen(const struct sk_buff *skb) { return tcp_skb_pcount(skb) == 1 ? skb->len : tcp_skb_mss(skb); } static int skb_can_shift(const struct sk_buff *skb) { return !skb_headlen(skb) && skb_is_nonlinear(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) { struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *prev; int mss; int pcount = 0; int len; int in_sack; if (!sk_can_gso(sk)) goto fallback; if (!dup_sack && (TCP_SKB_CB(skb)->sacked & (TCPCB_LOST|TCPCB_SACKED_RETRANS)) == TCPCB_SACKED_RETRANS) goto fallback; if (!skb_can_shift(skb)) goto fallback; if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una)) goto fallback; if (unlikely(skb == tcp_write_queue_head(sk))) goto fallback; prev = tcp_write_queue_prev(sk, skb); if ((TCP_SKB_CB(prev)->sacked & TCPCB_TAGBITS) != TCPCB_SACKED_ACKED) goto fallback; in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq) && !before(end_seq, TCP_SKB_CB(skb)->end_seq); if (in_sack) { len = skb->len; pcount = tcp_skb_pcount(skb); mss = tcp_skb_seglen(skb); if (mss != tcp_skb_seglen(prev)) goto fallback; } else { if (!after(TCP_SKB_CB(skb)->end_seq, start_seq)) goto noop; if (tcp_skb_pcount(skb) <= 1) goto noop; in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq); if (!in_sack) { goto fallback; } len = end_seq - TCP_SKB_CB(skb)->seq; BUG_ON(len < 0); BUG_ON(len > skb->len); mss = tcp_skb_mss(skb); if (mss != tcp_skb_seglen(prev)) goto fallback; if (len == mss) { pcount = 1; } else if (len < mss) { goto noop; } else { pcount = len / mss; len = pcount * mss; } } if (!after(TCP_SKB_CB(skb)->seq + len, tp->snd_una)) goto fallback; if (!skb_shift(prev, skb, len)) goto fallback; if (!tcp_shifted_skb(sk, skb, state, pcount, len, mss, dup_sack)) goto out; if (prev == tcp_write_queue_tail(sk)) 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; 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); } out: state->fack_count += pcount; return prev; noop: return skb; fallback: NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SACKSHIFTFALLBACK); return NULL; } 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) { 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; if (skb == tcp_send_head(sk)) break; if (!before(TCP_SKB_CB(skb)->seq, end_seq)) break; if ((next_dup != NULL) && before(TCP_SKB_CB(skb)->seq, next_dup->end_seq)) { in_sack = tcp_match_skb_to_sack(sk, skb, next_dup->start_seq, next_dup->end_seq); if (in_sack > 0) dup_sack = 1; } if (in_sack <= 0) { tmp = tcp_shift_skb_data(sk, skb, state, start_seq, end_seq, dup_sack); if (tmp != NULL) { if (tmp != skb) { skb = tmp; continue; } in_sack = 0; } else { in_sack = tcp_match_skb_to_sack(sk, skb, start_seq, end_seq); } } if (unlikely(in_sack < 0)) break; if (in_sack) { TCP_SKB_CB(skb)->sacked = tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq, dup_sack, tcp_skb_pcount(skb)); 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; } 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; state->fack_count += tcp_skb_pcount(skb); } return skb; } static struct sk_buff *tcp_maybe_skipping_dsack(struct sk_buff *skb, struct sock *sk, struct tcp_sack_block *next_dup, struct tcp_sacktag_state *state, u32 skip_to_seq) { if (next_dup == NULL) return skb; if (before(next_dup->start_seq, skip_to_seq)) { skb = tcp_sacktag_skip(skb, sk, state, next_dup->start_seq); skb = tcp_sacktag_walk(skb, sk, NULL, state, next_dup->start_seq, next_dup->end_seq, 1); } return skb; } static int tcp_sack_cache_ok(const struct tcp_sock *tp, const struct tcp_sack_block *cache) { return cache < tp->recv_sack_cache + ARRAY_SIZE(tp->recv_sack_cache); } static int tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb, u32 prior_snd_una) { const struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); const unsigned char *ptr = (skb_transport_header(ack_skb) + TCP_SKB_CB(ack_skb)->sacked); struct tcp_sack_block_wire *sp_wire = (struct tcp_sack_block_wire *)(ptr+2); struct tcp_sack_block sp[TCP_NUM_SACKS]; struct tcp_sack_block *cache; struct tcp_sacktag_state state; 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; int i, j; int first_sack_index; state.flag = 0; state.reord = tp->packets_out; if (!tp->sacked_out) { if (WARN_ON(tp->fackets_out)) tp->fackets_out = 0; tcp_highest_sack_reset(sk); } found_dup_sack = tcp_check_dsack(sk, ack_skb, sp_wire, num_sacks, prior_snd_una); if (found_dup_sack) state.flag |= FLAG_DSACKING_ACK; if (before(TCP_SKB_CB(ack_skb)->ack_seq, prior_snd_una - tp->max_window)) return 0; if (!tp->packets_out) goto out; used_sacks = 0; first_sack_index = 0; for (i = 0; i < num_sacks; i++) { int dup_sack = !i && found_dup_sack; sp[used_sacks].start_seq = get_unaligned_be32(&sp_wire[i].start_seq); sp[used_sacks].end_seq = get_unaligned_be32(&sp_wire[i].end_seq); if (!tcp_is_sackblock_valid(tp, dup_sack, sp[used_sacks].start_seq, sp[used_sacks].end_seq)) { int mib_idx; if (dup_sack) { if (!tp->undo_marker) mib_idx = LINUX_MIB_TCPDSACKIGNOREDNOUNDO; else mib_idx = LINUX_MIB_TCPDSACKIGNOREDOLD; } else { if ((TCP_SKB_CB(ack_skb)->ack_seq != tp->snd_una) && !after(sp[used_sacks].end_seq, tp->snd_una)) continue; mib_idx = LINUX_MIB_TCPSACKDISCARD; } NET_INC_STATS_BH(sock_net(sk), mib_idx); if (i == 0) first_sack_index = -1; continue; } if (!after(sp[used_sacks].end_seq, prior_snd_una)) continue; used_sacks++; } for (i = used_sacks - 1; i > 0; i--) { for (j = 0; j < i; j++) { if (after(sp[j].start_seq, sp[j + 1].start_seq)) { swap(sp[j], sp[j + 1]); if (j == first_sack_index) first_sack_index = j + 1; } } } skb = tcp_write_queue_head(sk); state.fack_count = 0; i = 0; if (!tp->sacked_out) { cache = tp->recv_sack_cache + ARRAY_SIZE(tp->recv_sack_cache); } else { cache = tp->recv_sack_cache; while (tcp_sack_cache_ok(tp, cache) && !cache->start_seq && !cache->end_seq) cache++; } 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)); struct tcp_sack_block *next_dup = NULL; if (found_dup_sack && ((i + 1) == first_sack_index)) next_dup = &sp[i + 1]; while (tcp_sack_cache_ok(tp, cache) && !before(start_seq, cache->end_seq)) cache++; if (tcp_sack_cache_ok(tp, cache) && !dup_sack && after(end_seq, cache->start_seq)) { if (before(start_seq, cache->start_seq)) { skb = tcp_sacktag_skip(skb, sk, &state, start_seq); skb = tcp_sacktag_walk(skb, sk, next_dup, &state, start_seq, cache->start_seq, dup_sack); } if (!after(end_seq, cache->end_seq)) goto advance_sp; skb = tcp_maybe_skipping_dsack(skb, sk, next_dup, &state, cache->end_seq); if (tcp_highest_sack_seq(tp) == cache->end_seq) { skb = tcp_highest_sack(sk); if (skb == NULL) break; state.fack_count = tp->fackets_out; cache++; goto walk; } skb = tcp_sacktag_skip(skb, sk, &state, cache->end_seq); cache++; continue; } if (!before(start_seq, tcp_highest_sack_seq(tp))) { skb = tcp_highest_sack(sk); if (skb == NULL) break; state.fack_count = tp->fackets_out; } skb = tcp_sacktag_skip(skb, sk, &state, start_seq); walk: skb = tcp_sacktag_walk(skb, sk, next_dup, &state, start_seq, end_seq, dup_sack); advance_sp: if (after(end_seq, tp->frto_highmark)) state.flag &= ~FLAG_ONLY_ORIG_SACKED; i++; } for (i = 0; i < ARRAY_SIZE(tp->recv_sack_cache) - used_sacks; i++) { tp->recv_sack_cache[i].start_seq = 0; tp->recv_sack_cache[i].end_seq = 0; } for (j = 0; j < used_sacks; j++) tp->recv_sack_cache[i++] = sp[j]; tcp_mark_lost_retrans(sk); tcp_verify_left_out(tp); if ((state.reord < tp->fackets_out) && ((icsk->icsk_ca_state != TCP_CA_Loss) || tp->undo_marker) && (!tp->frto_highmark || after(tp->snd_una, tp->frto_highmark))) tcp_update_reordering(sk, tp->fackets_out - state.reord, 0); out: #if FASTRETRANS_DEBUG > 0 WARN_ON((int)tp->sacked_out < 0); WARN_ON((int)tp->lost_out < 0); WARN_ON((int)tp->retrans_out < 0); WARN_ON((int)tcp_packets_in_flight(tp) < 0); #endif return state.flag; } static int tcp_limit_reno_sacked(struct tcp_sock *tp) { u32 holes; holes = max(tp->lost_out, 1U); holes = min(holes, tp->packets_out); if ((tp->sacked_out + holes) > tp->packets_out) { tp->sacked_out = tp->packets_out - holes; return 1; } return 0; } 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); } static void tcp_add_reno_sack(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); tp->sacked_out++; tcp_check_reno_reordering(sk, 0); tcp_verify_left_out(tp); } static void tcp_remove_reno_sacks(struct sock *sk, int acked) { struct tcp_sock *tp = tcp_sk(sk); if (acked > 0) { if (acked - 1 >= tp->sacked_out) tp->sacked_out = 0; else tp->sacked_out -= acked - 1; } tcp_check_reno_reordering(sk, acked); tcp_verify_left_out(tp); } static inline void tcp_reset_reno_sack(struct tcp_sock *tp) { tp->sacked_out = 0; } static int tcp_is_sackfrto(const struct tcp_sock *tp) { return (sysctl_tcp_frto == 0x2) && !tcp_is_reno(tp); } int 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; if (icsk->icsk_mtup.probe_size) return 0; if (tcp_is_sackfrto(tp)) return 1; if (tp->retrans_out > 1) return 0; skb = tcp_write_queue_head(sk); #ifdef CONFIG_HTC_NETWORK_MODIFY if (IS_ERR(skb) || (!skb)) printk(KERN_ERR "[NET] skb is NULL in %s!\n", __func__); #endif if (tcp_skb_is_last(sk, skb)) return 1; skb = tcp_write_queue_next(sk, skb); tcp_for_write_queue_from(skb, sk) { if (skb == tcp_send_head(sk)) break; if (TCP_SKB_CB(skb)->sacked & TCPCB_RETRANS) return 0; if (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) break; } return 1; } void tcp_enter_frto(struct sock *sk) { const struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; if ((!tp->frto_counter && icsk->icsk_ca_state <= TCP_CA_Disorder) || tp->snd_una == tp->high_seq || ((icsk->icsk_ca_state == TCP_CA_Loss || tp->frto_counter) && !icsk->icsk_retransmits)) { tp->prior_ssthresh = tcp_current_ssthresh(sk); if (tp->frto_counter) { u32 stored_cwnd; stored_cwnd = tp->snd_cwnd; tp->snd_cwnd = 2; tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk); tp->snd_cwnd = stored_cwnd; } else { tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk); } tcp_ca_event(sk, CA_EVENT_FRTO); } tp->undo_marker = tp->snd_una; tp->undo_retrans = 0; skb = tcp_write_queue_head(sk); #ifdef CONFIG_HTC_NETWORK_MODIFY if (IS_ERR(skb) || (!skb)) printk(KERN_ERR "[NET] skb is NULL in %s!\n", __func__); #endif if (TCP_SKB_CB(skb)->sacked & TCPCB_RETRANS) tp->undo_marker = 0; if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS) { TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS; tp->retrans_out -= tcp_skb_pcount(skb); } tcp_verify_left_out(tp); tp->snd_cwnd = min(tp->snd_cwnd, tcp_packets_in_flight(tp) + 1); if (tcp_is_sackfrto(tp) && (tp->frto_counter || ((1 << icsk->icsk_ca_state) & (TCPF_CA_Recovery|TCPF_CA_Loss))) && after(tp->high_seq, tp->snd_una)) { tp->frto_highmark = tp->high_seq; } else { tp->frto_highmark = tp->snd_nxt; } tcp_set_ca_state(sk, TCP_CA_Disorder); tp->high_seq = tp->snd_nxt; tp->frto_counter = 1; } static void tcp_enter_frto_loss(struct sock *sk, int allowed_segments, int flag) { struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; tp->lost_out = 0; tp->retrans_out = 0; if (tcp_is_reno(tp)) tcp_reset_reno_sack(tp); tcp_for_write_queue(skb, sk) { if (skb == tcp_send_head(sk)) break; TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST; if ((tp->frto_counter == 1) && !(flag & FLAG_DATA_ACKED)) { if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS) tp->retrans_out += tcp_skb_pcount(skb); flag |= FLAG_DATA_ACKED; } else { if (TCP_SKB_CB(skb)->sacked & TCPCB_RETRANS) tp->undo_marker = 0; TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS; } if (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) { TCP_SKB_CB(skb)->sacked |= TCPCB_LOST; tp->lost_out += tcp_skb_pcount(skb); tp->retransmit_high = TCP_SKB_CB(skb)->end_seq; } } tcp_verify_left_out(tp); tp->snd_cwnd = tcp_packets_in_flight(tp) + allowed_segments; tp->snd_cwnd_cnt = 0; tp->snd_cwnd_stamp = tcp_time_stamp; tp->frto_counter = 0; tp->bytes_acked = 0; tp->reordering = min_t(unsigned int, tp->reordering, sysctl_tcp_reordering); tcp_set_ca_state(sk, TCP_CA_Loss); tp->high_seq = tp->snd_nxt; TCP_ECN_queue_cwr(tp); tcp_clear_all_retrans_hints(tp); } static void tcp_clear_retrans_partial(struct tcp_sock *tp) { tp->retrans_out = 0; tp->lost_out = 0; tp->undo_marker = 0; tp->undo_retrans = -1; } void tcp_clear_retrans(struct tcp_sock *tp) { tcp_clear_retrans_partial(tp); tp->fackets_out = 0; tp->sacked_out = 0; } void tcp_enter_loss(struct sock *sk, int how) { const struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; 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->prior_ssthresh = tcp_current_ssthresh(sk); tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk); tcp_ca_event(sk, CA_EVENT_LOSS); } tp->snd_cwnd = 1; tp->snd_cwnd_cnt = 0; tp->snd_cwnd_stamp = tcp_time_stamp; tp->bytes_acked = 0; tcp_clear_retrans_partial(tp); if (tcp_is_reno(tp)) tcp_reset_reno_sack(tp); if (!how) { tp->undo_marker = tp->snd_una; } else { 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; if (TCP_SKB_CB(skb)->sacked & TCPCB_RETRANS) tp->undo_marker = 0; TCP_SKB_CB(skb)->sacked &= (~TCPCB_TAGBITS)|TCPCB_SACKED_ACKED; if (!(TCP_SKB_CB(skb)->sacked&TCPCB_SACKED_ACKED) || how) { TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_ACKED; TCP_SKB_CB(skb)->sacked |= TCPCB_LOST; tp->lost_out += tcp_skb_pcount(skb); tp->retransmit_high = TCP_SKB_CB(skb)->end_seq; } } tcp_verify_left_out(tp); tp->reordering = min_t(unsigned int, tp->reordering, sysctl_tcp_reordering); tcp_set_ca_state(sk, TCP_CA_Loss); tp->high_seq = tp->snd_nxt; TCP_ECN_queue_cwr(tp); tp->frto_counter = 0; } static int tcp_check_sack_reneging(struct sock *sk, int flag) { if (flag & FLAG_SACK_RENEGING) { struct inet_connection_sock *icsk = inet_csk(sk); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSACKRENEGING); tcp_enter_loss(sk, 1); icsk->icsk_retransmits++; 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 0; } static inline int tcp_fackets_out(const struct tcp_sock *tp) { return tcp_is_reno(tp) ? tp->sacked_out + 1 : tp->fackets_out; } static inline int tcp_dupack_heuristics(const struct tcp_sock *tp) { return tcp_is_fack(tp) ? tp->fackets_out : tp->sacked_out + 1; } static inline int tcp_skb_timedout(const struct sock *sk, const struct sk_buff *skb) { return tcp_time_stamp - TCP_SKB_CB(skb)->when > inet_csk(sk)->icsk_rto; } static inline int tcp_head_timedout(const struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); return tp->packets_out && tcp_skb_timedout(sk, tcp_write_queue_head(sk)); } static int tcp_time_to_recover(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); __u32 packets_out; if (tp->frto_counter) return 0; if (tp->lost_out) return 1; if (tcp_dupack_heuristics(tp) > tp->reordering) return 1; if (tcp_is_fack(tp) && tcp_head_timedout(sk)) return 1; packets_out = tp->packets_out; if (packets_out <= tp->reordering && tp->sacked_out >= max_t(__u32, packets_out/2, sysctl_tcp_reordering) && !tcp_may_send_now(sk)) { return 1; } 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 0; } static void tcp_timeout_skbs(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; if (!tcp_is_fack(tp) || !tcp_head_timedout(sk)) return; skb = tp->scoreboard_skb_hint; if (tp->scoreboard_skb_hint == NULL) skb = tcp_write_queue_head(sk); #ifdef CONFIG_HTC_NETWORK_MODIFY if (IS_ERR(skb) || (!skb)) printk(KERN_ERR "[NET] skb is NULL in %s!\n", __func__); #endif tcp_for_write_queue_from(skb, sk) { if (skb == tcp_send_head(sk)) break; if (!tcp_skb_timedout(sk, skb)) break; tcp_skb_mark_lost(tp, skb); } tp->scoreboard_skb_hint = skb; tcp_verify_left_out(tp); } static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head) { struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; int cnt, oldcnt; int err; unsigned int mss; 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; if (mark_head && skb != tcp_write_queue_head(sk)) return; } else { skb = tcp_write_queue_head(sk); cnt = 0; } #ifdef CONFIG_HTC_NETWORK_MODIFY if (IS_ERR(skb) || (!skb)) printk(KERN_ERR "[NET] skb is NULL in %s!\n", __func__); #endif tcp_for_write_queue_from(skb, sk) { if (skb == tcp_send_head(sk)) break; tp->lost_skb_hint = skb; tp->lost_cnt_hint = cnt; if (after(TCP_SKB_CB(skb)->end_seq, loss_high)) break; oldcnt = cnt; if (tcp_is_fack(tp) || 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)) || (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED) || (oldcnt >= packets)) break; mss = skb_shinfo(skb)->gso_size; err = tcp_fragment(sk, skb, (packets - oldcnt) * mss, mss); if (err < 0) break; cnt = packets; } tcp_skb_mark_lost(tp, skb); if (mark_head) break; } tcp_verify_left_out(tp); } static void tcp_update_scoreboard(struct sock *sk, int fast_rexmit) { struct tcp_sock *tp = tcp_sk(sk); 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) tcp_mark_head_lost(sk, sacked_upto, 0); else if (fast_rexmit) tcp_mark_head_lost(sk, 1, 1); } tcp_timeout_skbs(sk); } static inline void tcp_moderate_cwnd(struct tcp_sock *tp) { tp->snd_cwnd = min(tp->snd_cwnd, tcp_packets_in_flight(tp) + tcp_max_burst(tp)); tp->snd_cwnd_stamp = tcp_time_stamp; } static inline u32 tcp_cwnd_min(const struct sock *sk) { const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; return ca_ops->min_cwnd ? ca_ops->min_cwnd(sk) : tcp_sk(sk)->snd_ssthresh; } static void tcp_cwnd_down(struct sock *sk, int flag) { struct tcp_sock *tp = tcp_sk(sk); int decr = tp->snd_cwnd_cnt + 1; if ((flag & (FLAG_ANY_PROGRESS | FLAG_DSACKING_ACK)) || (tcp_is_reno(tp) && !(flag & FLAG_NOT_DUP))) { tp->snd_cwnd_cnt = decr & 1; decr >>= 1; if (decr && tp->snd_cwnd > tcp_cwnd_min(sk)) tp->snd_cwnd -= decr; tp->snd_cwnd = min(tp->snd_cwnd, tcp_packets_in_flight(tp) + 1); tp->snd_cwnd_stamp = tcp_time_stamp; } } static inline int tcp_packet_delayed(const struct tcp_sock *tp) { return !tp->retrans_stamp || (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr && before(tp->rx_opt.rcv_tsecr, tp->retrans_stamp)); } #if FASTRETRANS_DEBUG > 1 static void DBGUNDO(struct sock *sk, const char *msg) { struct tcp_sock *tp = tcp_sk(sk); 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); } #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); } #endif } #else #define DBGUNDO(x...) do { } while (0) #endif static void tcp_undo_cwr(struct sock *sk, const bool undo_ssthresh) { struct tcp_sock *tp = tcp_sk(sk); if (tp->prior_ssthresh) { const struct inet_connection_sock *icsk = inet_csk(sk); if (icsk->icsk_ca_ops->undo_cwnd) tp->snd_cwnd = icsk->icsk_ca_ops->undo_cwnd(sk); else tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh << 1); if (undo_ssthresh && tp->prior_ssthresh > tp->snd_ssthresh) { tp->snd_ssthresh = tp->prior_ssthresh; TCP_ECN_withdraw_cwr(tp); } } else { tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh); } tp->snd_cwnd_stamp = tcp_time_stamp; } static inline int tcp_may_undo(const struct tcp_sock *tp) { return tp->undo_marker && (!tp->undo_retrans || tcp_packet_delayed(tp)); } static int tcp_try_undo_recovery(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); if (tcp_may_undo(tp)) { int mib_idx; DBGUNDO(sk, inet_csk(sk)->icsk_ca_state == TCP_CA_Loss ? "loss" : "retrans"); tcp_undo_cwr(sk, true); if (inet_csk(sk)->icsk_ca_state == TCP_CA_Loss) mib_idx = LINUX_MIB_TCPLOSSUNDO; else mib_idx = LINUX_MIB_TCPFULLUNDO; NET_INC_STATS_BH(sock_net(sk), mib_idx); tp->undo_marker = 0; } if (tp->snd_una == tp->high_seq && tcp_is_reno(tp)) { tcp_moderate_cwnd(tp); return 1; } tcp_set_ca_state(sk, TCP_CA_Open); return 0; } static void tcp_try_undo_dsack(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); if (tp->undo_marker && !tp->undo_retrans) { DBGUNDO(sk, "D-SACK"); tcp_undo_cwr(sk, true); tp->undo_marker = 0; NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPDSACKUNDO); } } static int 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; skb = tcp_write_queue_head(sk); if (unlikely(skb && TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS)) return 1; return 0; } static int tcp_try_undo_partial(struct sock *sk, int acked) { struct tcp_sock *tp = tcp_sk(sk); int failed = tcp_is_reno(tp) || (tcp_fackets_out(tp) > tp->reordering); if (tcp_may_undo(tp)) { if (!tcp_any_retrans_done(sk)) tp->retrans_stamp = 0; tcp_update_reordering(sk, tcp_fackets_out(tp) + acked, 1); DBGUNDO(sk, "Hoe"); tcp_undo_cwr(sk, false); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPPARTIALUNDO); failed = 0; } return failed; } static int tcp_try_undo_loss(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); if (tcp_may_undo(tp)) { struct sk_buff *skb; tcp_for_write_queue(skb, sk) { if (skb == tcp_send_head(sk)) break; TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST; } tcp_clear_all_retrans_hints(tp); DBGUNDO(sk, "partial loss"); tp->lost_out = 0; tcp_undo_cwr(sk, true); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPLOSSUNDO); inet_csk(sk)->icsk_retransmits = 0; tp->undo_marker = 0; if (tcp_is_sack(tp)) tcp_set_ca_state(sk, TCP_CA_Open); return 1; } return 0; } static inline void tcp_complete_cwr(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); if (tp->undo_marker) { if (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR) { tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh); tp->snd_cwnd_stamp = tcp_time_stamp; } else if (tp->snd_ssthresh < TCP_INFINITE_SSTHRESH) { tp->snd_cwnd = tp->snd_ssthresh; tp->snd_cwnd_stamp = tcp_time_stamp; } } tcp_ca_event(sk, CA_EVENT_COMPLETE_CWR); } static void tcp_try_keep_open(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); int state = TCP_CA_Open; if (tcp_left_out(tp) || tcp_any_retrans_done(sk)) state = TCP_CA_Disorder; if (inet_csk(sk)->icsk_ca_state != state) { tcp_set_ca_state(sk, state); tp->high_seq = tp->snd_nxt; } } static void tcp_try_to_open(struct sock *sk, int flag) { struct tcp_sock *tp = tcp_sk(sk); tcp_verify_left_out(tp); if (!tp->frto_counter && !tcp_any_retrans_done(sk)) tp->retrans_stamp = 0; if (flag & FLAG_ECE) tcp_enter_cwr(sk, 1); if (inet_csk(sk)->icsk_ca_state != TCP_CA_CWR) { tcp_try_keep_open(sk); if (inet_csk(sk)->icsk_ca_state != TCP_CA_Open) tcp_moderate_cwnd(tp); } else { tcp_cwnd_down(sk, flag); } } static void tcp_mtup_probe_failed(struct sock *sk) { struct inet_connection_sock *icsk = inet_csk(sk); icsk->icsk_mtup.search_high = icsk->icsk_mtup.probe_size - 1; icsk->icsk_mtup.probe_size = 0; } static void tcp_mtup_probe_success(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); struct inet_connection_sock *icsk = inet_csk(sk); tp->prior_ssthresh = tcp_current_ssthresh(sk); tp->snd_cwnd = tp->snd_cwnd * tcp_mss_to_mtu(sk, tp->mss_cache) / icsk->icsk_mtup.probe_size; tp->snd_cwnd_cnt = 0; tp->snd_cwnd_stamp = tcp_time_stamp; tp->snd_ssthresh = tcp_current_ssthresh(sk); icsk->icsk_mtup.search_low = icsk->icsk_mtup.probe_size; icsk->icsk_mtup.probe_size = 0; tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); } void tcp_simple_retransmit(struct sock *sk) { const struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; unsigned int mss = tcp_current_mss(sk); u32 prior_lost = tp->lost_out; tcp_for_write_queue(skb, sk) { if (skb == tcp_send_head(sk)) break; if (tcp_skb_seglen(skb) > mss && !(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) { if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS) { TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS; tp->retrans_out -= tcp_skb_pcount(skb); } tcp_skb_mark_lost_uncond_verify(tp, skb); } } tcp_clear_retrans_hints_partial(tp); if (prior_lost == tp->lost_out) return; if (tcp_is_reno(tp)) tcp_limit_reno_sacked(tp); tcp_verify_left_out(tp); if (icsk->icsk_ca_state != TCP_CA_Loss) { tp->high_seq = tp->snd_nxt; tp->snd_ssthresh = tcp_current_ssthresh(sk); tp->prior_ssthresh = 0; tp->undo_marker = 0; tcp_set_ca_state(sk, TCP_CA_Loss); } tcp_xmit_retransmit_queue(sk); } EXPORT_SYMBOL(tcp_simple_retransmit); static void tcp_update_cwnd_in_recovery(struct sock *sk, int newly_acked_sacked, int fast_rexmit, int flag) { struct tcp_sock *tp = tcp_sk(sk); int sndcnt = 0; int delta = tp->snd_ssthresh - tcp_packets_in_flight(tp); if (tcp_packets_in_flight(tp) > tp->snd_ssthresh) { u64 dividend = (u64)tp->snd_ssthresh * tp->prr_delivered + tp->prior_cwnd - 1; sndcnt = div_u64(dividend, tp->prior_cwnd) - tp->prr_out; } else { sndcnt = min_t(int, delta, max_t(int, tp->prr_delivered - tp->prr_out, newly_acked_sacked) + 1); } sndcnt = max(sndcnt, (fast_rexmit ? 1 : 0)); tp->snd_cwnd = tcp_packets_in_flight(tp) + sndcnt; } static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int newly_acked_sacked, bool is_dupack, int flag) { struct inet_connection_sock *icsk = inet_csk(sk); 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; if (WARN_ON(!tp->packets_out && tp->sacked_out)) tp->sacked_out = 0; if (WARN_ON(!tp->sacked_out && tp->fackets_out)) tp->fackets_out = 0; if (flag & FLAG_ECE) tp->prior_ssthresh = 0; if (tcp_check_sack_reneging(sk, flag)) return; tcp_verify_left_out(tp); if (icsk->icsk_ca_state == TCP_CA_Open) { WARN_ON(tp->retrans_out != 0); tp->retrans_stamp = 0; } else if (!before(tp->snd_una, tp->high_seq)) { switch (icsk->icsk_ca_state) { case TCP_CA_Loss: icsk->icsk_retransmits = 0; if (tcp_try_undo_recovery(sk)) return; break; case TCP_CA_CWR: if (tp->snd_una != tp->high_seq) { tcp_complete_cwr(sk); tcp_set_ca_state(sk, TCP_CA_Open); } break; case TCP_CA_Recovery: if (tcp_is_reno(tp)) tcp_reset_reno_sack(tp); if (tcp_try_undo_recovery(sk)) return; tcp_complete_cwr(sk); break; } } switch (icsk->icsk_ca_state) { case TCP_CA_Recovery: if (!(flag & FLAG_SND_UNA_ADVANCED)) { if (tcp_is_reno(tp) && is_dupack) tcp_add_reno_sack(sk); } else do_lost = tcp_try_undo_partial(sk, pkts_acked); break; case TCP_CA_Loss: if (flag & FLAG_DATA_ACKED) icsk->icsk_retransmits = 0; if (tcp_is_reno(tp) && flag & FLAG_SND_UNA_ADVANCED) tcp_reset_reno_sack(tp); if (!tcp_try_undo_loss(sk)) { tcp_moderate_cwnd(tp); tcp_xmit_retransmit_queue(sk); return; } if (icsk->icsk_ca_state != TCP_CA_Open) return; default: if (tcp_is_reno(tp)) { if (flag & FLAG_SND_UNA_ADVANCED) tcp_reset_reno_sack(tp); if (is_dupack) tcp_add_reno_sack(sk); } if (icsk->icsk_ca_state <= TCP_CA_Disorder) tcp_try_undo_dsack(sk); if (!tcp_time_to_recover(sk)) { tcp_try_to_open(sk, flag); return; } if (icsk->icsk_ca_state < TCP_CA_CWR && icsk->icsk_mtup.probe_size && tp->snd_una == tp->mtu_probe.probe_seq_start) { tcp_mtup_probe_failed(sk); tp->snd_cwnd++; tcp_simple_retransmit(sk); return; } 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 ? : -1; 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); fast_rexmit = 1; } if (do_lost || (tcp_is_fack(tp) && tcp_head_timedout(sk))) tcp_update_scoreboard(sk, fast_rexmit); tp->prr_delivered += newly_acked_sacked; tcp_update_cwnd_in_recovery(sk, newly_acked_sacked, fast_rexmit, flag); tcp_xmit_retransmit_queue(sk); } void tcp_valid_rtt_meas(struct sock *sk, u32 seq_rtt) { tcp_rtt_estimator(sk, seq_rtt); tcp_set_rto(sk); inet_csk(sk)->icsk_backoff = 0; } EXPORT_SYMBOL(tcp_valid_rtt_meas); static void tcp_ack_saw_tstamp(struct sock *sk, int flag) { struct tcp_sock *tp = tcp_sk(sk); tcp_valid_rtt_meas(sk, tcp_time_stamp - tp->rx_opt.rcv_tsecr); } static void tcp_ack_no_tstamp(struct sock *sk, u32 seq_rtt, int flag) { if (flag & FLAG_RETRANS_DATA_ACKED) return; tcp_valid_rtt_meas(sk, seq_rtt); } static inline void tcp_ack_update_rtt(struct sock *sk, const int flag, const s32 seq_rtt) { const struct tcp_sock *tp = tcp_sk(sk); if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr) tcp_ack_saw_tstamp(sk, flag); else if (seq_rtt >= 0) tcp_ack_no_tstamp(sk, seq_rtt, flag); } static void tcp_cong_avoid(struct sock *sk, u32 ack, u32 in_flight) { const struct inet_connection_sock *icsk = inet_csk(sk); icsk->icsk_ca_ops->cong_avoid(sk, ack, in_flight); tcp_sk(sk)->snd_cwnd_stamp = tcp_time_stamp; } static void tcp_rearm_rto(struct sock *sk) { const 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); } } static u32 tcp_tso_acked(struct sock *sk, struct sk_buff *skb) { struct tcp_sock *tp = tcp_sk(sk); u32 packets_acked; BUG_ON(!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una)); packets_acked = tcp_skb_pcount(skb); if (tcp_trim_head(sk, skb, tp->snd_una - TCP_SKB_CB(skb)->seq)) return 0; packets_acked -= tcp_skb_pcount(skb); if (packets_acked) { BUG_ON(tcp_skb_pcount(skb) == 0); BUG_ON(!before(TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq)); } return packets_acked; } static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets, u32 prior_snd_una) { struct tcp_sock *tp = tcp_sk(sk); const struct inet_connection_sock *icsk = inet_csk(sk); struct sk_buff *skb; u32 now = tcp_time_stamp; int fully_acked = 1; int flag = 0; u32 pkts_acked = 0; u32 reord = tp->packets_out; u32 prior_sacked = tp->sacked_out; s32 seq_rtt = -1; s32 ca_seq_rtt = -1; ktime_t last_ackt = net_invalid_timestamp(); while ((skb = tcp_write_queue_head(sk)) && skb != tcp_send_head(sk)) { struct tcp_skb_cb *scb = TCP_SKB_CB(skb); u32 acked_pcount; u8 sacked = scb->sacked; if (after(scb->end_seq, tp->snd_una)) { if (tcp_skb_pcount(skb) == 1 || !after(tp->snd_una, scb->seq)) break; acked_pcount = tcp_tso_acked(sk, skb); if (!acked_pcount) break; fully_acked = 0; } else { acked_pcount = tcp_skb_pcount(skb); } if (sacked & TCPCB_RETRANS) { if (sacked & TCPCB_SACKED_RETRANS) tp->retrans_out -= acked_pcount; flag |= FLAG_RETRANS_DATA_ACKED; ca_seq_rtt = -1; seq_rtt = -1; if ((flag & FLAG_DATA_ACKED) || (acked_pcount > 1)) flag |= FLAG_NONHEAD_RETRANS_ACKED; } else { ca_seq_rtt = now - scb->when; last_ackt = skb->tstamp; if (seq_rtt < 0) { seq_rtt = ca_seq_rtt; } if (!(sacked & TCPCB_SACKED_ACKED)) reord = min(pkts_acked, reord); } if (sacked & TCPCB_SACKED_ACKED) tp->sacked_out -= acked_pcount; if (sacked & TCPCB_LOST) tp->lost_out -= acked_pcount; tp->packets_out -= acked_pcount; pkts_acked += acked_pcount; if (!(scb->tcp_flags & TCPHDR_SYN)) { flag |= FLAG_DATA_ACKED; } else { flag |= FLAG_SYN_ACKED; tp->retrans_stamp = 0; } if (!fully_acked) break; tcp_unlink_write_queue(skb, sk); sk_wmem_free_skb(sk, skb); tp->scoreboard_skb_hint = NULL; if (skb == tp->retransmit_skb_hint) tp->retransmit_skb_hint = NULL; if (skb == tp->lost_skb_hint) tp->lost_skb_hint = NULL; } if (likely(between(tp->snd_up, prior_snd_una, tp->snd_una))) tp->snd_up = tp->snd_una; if (skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) flag |= FLAG_SACK_RENEGING; if (flag & FLAG_ACKED) { const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; if (unlikely(icsk->icsk_mtup.probe_size && !after(tp->mtu_probe.probe_seq_end, tp->snd_una))) { tcp_mtup_probe_success(sk); } tcp_ack_update_rtt(sk, flag, seq_rtt); tcp_rearm_rto(sk); if (tcp_is_reno(tp)) { tcp_remove_reno_sacks(sk, pkts_acked); } else { int delta; if (reord < prior_fackets) tcp_update_reordering(sk, tp->fackets_out - reord, 0); delta = tcp_is_fack(tp) ? pkts_acked : prior_sacked - tp->sacked_out; tp->lost_cnt_hint -= min(tp->lost_cnt_hint, delta); } tp->fackets_out -= min(pkts_acked, tp->fackets_out); if (ca_ops->pkts_acked) { s32 rtt_us = -1; if (!(flag & FLAG_RETRANS_DATA_ACKED)) { if (ca_ops->flags & TCP_CONG_RTT_STAMP && !ktime_equal(last_ackt, net_invalid_timestamp())) rtt_us = ktime_us_delta(ktime_get_real(), last_ackt); else if (ca_seq_rtt >= 0) rtt_us = jiffies_to_usecs(ca_seq_rtt); } ca_ops->pkts_acked(sk, pkts_acked, rtt_us); } } #if FASTRETRANS_DEBUG > 0 WARN_ON((int)tp->sacked_out < 0); WARN_ON((int)tp->lost_out < 0); WARN_ON((int)tp->retrans_out < 0); 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); tp->lost_out = 0; } if (tp->sacked_out) { printk(KERN_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); tp->retrans_out = 0; } } #endif return flag; } static void tcp_ack_probe(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); struct inet_connection_sock *icsk = inet_csk(sk); if (!after(TCP_SKB_CB(tcp_send_head(sk))->end_seq, tcp_wnd_end(tp))) { icsk->icsk_backoff = 0; inet_csk_clear_xmit_timer(sk, ICSK_TIME_PROBE0); } else { inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0, min(icsk->icsk_rto << icsk->icsk_backoff, TCP_RTO_MAX), TCP_RTO_MAX); } } static inline int tcp_ack_is_dubious(const struct sock *sk, const int flag) { return !(flag & FLAG_NOT_DUP) || (flag & FLAG_CA_ALERT) || inet_csk(sk)->icsk_ca_state != TCP_CA_Open; } static inline int tcp_may_raise_cwnd(const struct sock *sk, const int flag) { const struct tcp_sock *tp = tcp_sk(sk); return (!(flag & FLAG_ECE) || tp->snd_cwnd < tp->snd_ssthresh) && !((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_Recovery | TCPF_CA_CWR)); } static inline int tcp_may_update_window(const struct tcp_sock *tp, const u32 ack, const u32 ack_seq, const u32 nwin) { return after(ack, tp->snd_una) || after(ack_seq, tp->snd_wl1) || (ack_seq == tp->snd_wl1 && nwin > tp->snd_wnd); } static int tcp_ack_update_window(struct sock *sk, const struct sk_buff *skb, u32 ack, u32 ack_seq) { struct tcp_sock *tp = tcp_sk(sk); int flag = 0; u32 nwin = ntohs(tcp_hdr(skb)->window); if (likely(!tcp_hdr(skb)->syn)) nwin <<= tp->rx_opt.snd_wscale; if (tcp_may_update_window(tp, ack, ack_seq, nwin)) { flag |= FLAG_WIN_UPDATE; tcp_update_wl(tp, ack_seq); if (tp->snd_wnd != nwin) { tp->snd_wnd = nwin; tp->pred_flags = 0; tcp_fast_path_check(sk); if (nwin > tp->max_window) { tp->max_window = nwin; tcp_sync_mss(sk, inet_csk(sk)->icsk_pmtu_cookie); } } } tp->snd_una = ack; return flag; } static void tcp_conservative_spur_to_response(struct tcp_sock *tp) { tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh); tp->snd_cwnd_cnt = 0; tp->bytes_acked = 0; TCP_ECN_queue_cwr(tp); tcp_moderate_cwnd(tp); } static void tcp_ratehalving_spur_to_response(struct sock *sk) { tcp_enter_cwr(sk, 0); } static void tcp_undo_spur_to_response(struct sock *sk, int flag) { if (flag & FLAG_ECE) tcp_ratehalving_spur_to_response(sk); else tcp_undo_cwr(sk, true); } static int tcp_process_frto(struct sock *sk, int flag) { struct tcp_sock *tp = tcp_sk(sk); tcp_verify_left_out(tp); if (flag & FLAG_DATA_ACKED) inet_csk(sk)->icsk_retransmits = 0; if ((flag & FLAG_NONHEAD_RETRANS_ACKED) || ((tp->frto_counter >= 2) && (flag & FLAG_RETRANS_DATA_ACKED))) tp->undo_marker = 0; if (!before(tp->snd_una, tp->frto_highmark)) { tcp_enter_frto_loss(sk, (tp->frto_counter == 1 ? 2 : 3), flag); return 1; } if (!tcp_is_sackfrto(tp)) { if (!(flag & FLAG_ANY_PROGRESS) && (flag & FLAG_NOT_DUP)) return 1; if (!(flag & FLAG_DATA_ACKED)) { tcp_enter_frto_loss(sk, (tp->frto_counter == 1 ? 0 : 3), flag); return 1; } } else { if (!(flag & FLAG_DATA_ACKED) && (tp->frto_counter == 1)) { tp->snd_cwnd = min(tp->snd_cwnd, tcp_packets_in_flight(tp)); return 1; } if ((tp->frto_counter >= 2) && (!(flag & FLAG_FORWARD_PROGRESS) || ((flag & FLAG_DATA_SACKED) && !(flag & FLAG_ONLY_ORIG_SACKED)))) { if (!(flag & FLAG_FORWARD_PROGRESS) && (flag & FLAG_NOT_DUP)) return 1; tcp_enter_frto_loss(sk, 3, flag); return 1; } } if (tp->frto_counter == 1) { tp->snd_cwnd = tcp_packets_in_flight(tp) + 2; tp->frto_counter = 2; if (!tcp_may_send_now(sk)) tcp_enter_frto_loss(sk, 2, flag); return 1; } else { switch (sysctl_tcp_frto_response) { case 2: tcp_undo_spur_to_response(sk, flag); break; case 1: tcp_conservative_spur_to_response(tp); break; default: tcp_ratehalving_spur_to_response(sk); break; } tp->frto_counter = 0; tp->undo_marker = 0; NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSPURIOUSRTOS); } return 0; } static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) { struct inet_connection_sock *icsk = NULL; struct tcp_sock *tp = NULL; u32 prior_snd_una = 0; u32 ack_seq = 0; u32 ack = 0; bool is_dupack = false; u32 prior_in_flight = 0; u32 prior_fackets = 0; int prior_packets = 0; int prior_sacked = 0; int pkts_acked = 0; int newly_acked_sacked = 0; int frto_cwnd = 0; if ((!sk) || IS_ERR(sk)) goto invalid_ack; if ((!skb) || IS_ERR(skb)) goto invalid_ack; icsk = inet_csk(sk); tp = tcp_sk(sk); prior_snd_una = tp->snd_una; ack_seq = TCP_SKB_CB(skb)->seq; ack = TCP_SKB_CB(skb)->ack_seq; prior_sacked = tp->sacked_out; if (before(ack, prior_snd_una)) goto old_ack; if (after(ack, tp->snd_nxt)) goto invalid_ack; if (after(ack, prior_snd_una)) flag |= FLAG_SND_UNA_ADVANCED; if (sysctl_tcp_abc) { if (icsk->icsk_ca_state < TCP_CA_CWR) tp->bytes_acked += ack - prior_snd_una; else if (icsk->icsk_ca_state == TCP_CA_Loss) tp->bytes_acked += min(ack - prior_snd_una, tp->mss_cache); } prior_fackets = tp->fackets_out; prior_in_flight = tcp_packets_in_flight(tp); if (!(flag & FLAG_SLOWPATH) && after(ack, prior_snd_una)) { tcp_update_wl(tp, ack_seq); tp->snd_una = ack; flag |= FLAG_WIN_UPDATE; tcp_ca_event(sk, CA_EVENT_FAST_ACK); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPHPACKS); } else { if (ack_seq != TCP_SKB_CB(skb)->end_seq) flag |= FLAG_DATA; else NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPPUREACKS); flag |= tcp_ack_update_window(sk, skb, ack, ack_seq); if (TCP_SKB_CB(skb)->sacked) flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una); if (TCP_ECN_rcv_ecn_echo(tp, tcp_hdr(skb))) flag |= FLAG_ECE; tcp_ca_event(sk, CA_EVENT_SLOW_ACK); } sk->sk_err_soft = 0; icsk->icsk_probes_out = 0; tp->rcv_tstamp = tcp_time_stamp; prior_packets = tp->packets_out; if (!prior_packets) goto no_queue; flag |= tcp_clean_rtx_queue(sk, prior_fackets, prior_snd_una); pkts_acked = prior_packets - tp->packets_out; newly_acked_sacked = (prior_packets - prior_sacked) - (tp->packets_out - tp->sacked_out); if (tp->frto_counter) frto_cwnd = tcp_process_frto(sk, flag); if (before(tp->frto_highmark, tp->snd_una)) tp->frto_highmark = 0; if (tcp_ack_is_dubious(sk, flag)) { if ((flag & FLAG_DATA_ACKED) && !frto_cwnd && tcp_may_raise_cwnd(sk, flag)) tcp_cong_avoid(sk, ack, prior_in_flight); is_dupack = !(flag & (FLAG_SND_UNA_ADVANCED | FLAG_NOT_DUP)); tcp_fastretrans_alert(sk, pkts_acked, newly_acked_sacked, is_dupack, flag); } else { if ((flag & FLAG_DATA_ACKED) && !frto_cwnd) tcp_cong_avoid(sk, ack, prior_in_flight); } if ((flag & FLAG_FORWARD_PROGRESS) || !(flag & FLAG_NOT_DUP)) dst_confirm(__sk_dst_get(sk)); return 1; no_queue: if (flag & FLAG_DSACKING_ACK) tcp_fastretrans_alert(sk, pkts_acked, newly_acked_sacked, is_dupack, flag); if (tcp_send_head(sk)) tcp_ack_probe(sk); return 1; invalid_ack: SOCK_DEBUG(sk, "Ack %u after %u:%u\n", ack, tp->snd_una, tp->snd_nxt); return -1; old_ack: if (TCP_SKB_CB(skb)->sacked) { flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una); newly_acked_sacked = tp->sacked_out - prior_sacked; tcp_fastretrans_alert(sk, pkts_acked, newly_acked_sacked, is_dupack, flag); } SOCK_DEBUG(sk, "Ack %u before %u:%u\n", ack, tp->snd_una, tp->snd_nxt); return 0; } void tcp_parse_options(const struct sk_buff *skb, struct tcp_options_received *opt_rx, const u8 **hvpp, int estab) { const unsigned char *ptr; const struct tcphdr *th = tcp_hdr(skb); int length = (th->doff * 4) - sizeof(struct tcphdr); ptr = (const unsigned char *)(th + 1); opt_rx->saw_tstamp = 0; while (length > 0) { int opcode = *ptr++; int opsize; switch (opcode) { case TCPOPT_EOL: return; case TCPOPT_NOP: length--; continue; default: opsize = *ptr++; if (opsize < 2) return; if (opsize > length) return; switch (opcode) { case TCPOPT_MSS: if (opsize == TCPOLEN_MSS && th->syn && !estab) { u16 in_mss = get_unaligned_be16(ptr); if (in_mss) { if (opt_rx->user_mss && opt_rx->user_mss < in_mss) in_mss = opt_rx->user_mss; opt_rx->mss_clamp = in_mss; } } break; case TCPOPT_WINDOW: if (opsize == TCPOLEN_WINDOW && th->syn && !estab && sysctl_tcp_window_scaling) { __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); snd_wscale = 14; } opt_rx->snd_wscale = snd_wscale; } break; case TCPOPT_TIMESTAMP: if ((opsize == TCPOLEN_TIMESTAMP) && ((estab && opt_rx->tstamp_ok) || (!estab && sysctl_tcp_timestamps))) { opt_rx->saw_tstamp = 1; opt_rx->rcv_tsval = get_unaligned_be32(ptr); opt_rx->rcv_tsecr = get_unaligned_be32(ptr + 4); } break; case TCPOPT_SACK_PERM: if (opsize == TCPOLEN_SACK_PERM && th->syn && !estab && sysctl_tcp_sack) { opt_rx->sack_ok = TCP_SACK_SEEN; tcp_sack_reset(opt_rx); } break; case TCPOPT_SACK: if ((opsize >= (TCPOLEN_SACK_BASE + TCPOLEN_SACK_PERBLOCK)) && !((opsize - TCPOLEN_SACK_BASE) % TCPOLEN_SACK_PERBLOCK) && opt_rx->sack_ok) { TCP_SKB_CB(skb)->sacked = (ptr - 2) - (unsigned char *)th; } break; #ifdef CONFIG_TCP_MD5SIG case TCPOPT_MD5SIG: break; #endif case TCPOPT_COOKIE: switch (opsize) { case TCPOLEN_COOKIE_BASE: break; case TCPOLEN_COOKIE_PAIR: break; case TCPOLEN_COOKIE_MIN+0: case TCPOLEN_COOKIE_MIN+2: case TCPOLEN_COOKIE_MIN+4: case TCPOLEN_COOKIE_MIN+6: case TCPOLEN_COOKIE_MAX: opt_rx->cookie_plus = opsize; *hvpp = ptr; break; default: break; } break; } ptr += opsize-2; length -= opsize; } } } EXPORT_SYMBOL(tcp_parse_options); static int tcp_parse_aligned_timestamp(struct tcp_sock *tp, const struct tcphdr *th) { const __be32 *ptr = (const __be32 *)(th + 1); if (*ptr == htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP)) { tp->rx_opt.saw_tstamp = 1; ++ptr; tp->rx_opt.rcv_tsval = ntohl(*ptr); ++ptr; tp->rx_opt.rcv_tsecr = ntohl(*ptr); return 1; } return 0; } static int tcp_fast_parse_options(const struct sk_buff *skb, const struct tcphdr *th, struct tcp_sock *tp, const u8 **hvpp) { if (th->doff == (sizeof(*th) / 4)) { tp->rx_opt.saw_tstamp = 0; return 0; } else if (tp->rx_opt.tstamp_ok && th->doff == ((sizeof(*th) + TCPOLEN_TSTAMP_ALIGNED) / 4)) { if (tcp_parse_aligned_timestamp(tp, th)) return 1; } tcp_parse_options(skb, &tp->rx_opt, hvpp, 1); return 1; } #ifdef CONFIG_TCP_MD5SIG const u8 *tcp_parse_md5sig_option(const struct tcphdr *th) { int length = (th->doff << 2) - sizeof(*th); const u8 *ptr = (const u8 *)(th + 1); if (length < TCPOLEN_MD5SIG) return NULL; while (length > 0) { int opcode = *ptr++; int opsize; switch(opcode) { case TCPOPT_EOL: return NULL; case TCPOPT_NOP: length--; continue; default: opsize = *ptr++; if (opsize < 2 || opsize > length) return NULL; if (opcode == TCPOPT_MD5SIG) return opsize == TCPOLEN_MD5SIG ? ptr : NULL; } ptr += opsize - 2; length -= opsize; } return NULL; } EXPORT_SYMBOL(tcp_parse_md5sig_option); #endif static inline void tcp_store_ts_recent(struct tcp_sock *tp) { tp->rx_opt.ts_recent = tp->rx_opt.rcv_tsval; tp->rx_opt.ts_recent_stamp = get_seconds(); } static inline void tcp_replace_ts_recent(struct tcp_sock *tp, u32 seq) { if (tp->rx_opt.saw_tstamp && !after(seq, tp->rcv_wup)) { if (tcp_paws_check(&tp->rx_opt, 0)) tcp_store_ts_recent(tp); } } static int tcp_disordered_ack(const struct sock *sk, const struct sk_buff *skb) { const struct tcp_sock *tp = tcp_sk(sk); const struct tcphdr *th = tcp_hdr(skb); u32 seq = TCP_SKB_CB(skb)->seq; u32 ack = TCP_SKB_CB(skb)->ack_seq; return ( (th->ack && seq == TCP_SKB_CB(skb)->end_seq && seq == tp->rcv_nxt) && ack == tp->snd_una && !tcp_may_update_window(tp, ack, seq, ntohs(th->window) << tp->rx_opt.snd_wscale) && (s32)(tp->rx_opt.ts_recent - tp->rx_opt.rcv_tsval) <= (inet_csk(sk)->icsk_rto * 1024) / HZ); } static inline int tcp_paws_discard(const struct sock *sk, const struct sk_buff *skb) { const struct tcp_sock *tp = tcp_sk(sk); return !tcp_paws_check(&tp->rx_opt, TCP_PAWS_WINDOW) && !tcp_disordered_ack(sk, skb); } static inline int tcp_sequence(const struct tcp_sock *tp, u32 seq, u32 end_seq) { return !before(end_seq, tp->rcv_wup) && !after(seq, tp->rcv_nxt + tcp_receive_window(tp)); } static void tcp_reset(struct sock *sk) { switch (sk->sk_state) { case TCP_SYN_SENT: sk->sk_err = ECONNREFUSED; break; case TCP_CLOSE_WAIT: sk->sk_err = EPIPE; break; case TCP_CLOSE: return; default: sk->sk_err = ECONNRESET; } smp_wmb(); if (!sock_flag(sk, SOCK_DEAD)) sk->sk_error_report(sk); tcp_done(sk); } static void tcp_fin(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); inet_csk_schedule_ack(sk); sk->sk_shutdown |= RCV_SHUTDOWN; sock_set_flag(sk, SOCK_DONE); switch (sk->sk_state) { case TCP_SYN_RECV: case TCP_ESTABLISHED: tcp_set_state(sk, TCP_CLOSE_WAIT); inet_csk(sk)->icsk_ack.pingpong = 1; break; case TCP_CLOSE_WAIT: case TCP_CLOSING: break; case TCP_LAST_ACK: break; case TCP_FIN_WAIT1: tcp_send_ack(sk); tcp_set_state(sk, TCP_CLOSING); break; case TCP_FIN_WAIT2: tcp_send_ack(sk); tcp_time_wait(sk, TCP_TIME_WAIT, 0); break; default: pr_err("%s: Impossible, sk->sk_state=%d\n", __func__, sk->sk_state); break; } __skb_queue_purge(&tp->out_of_order_queue); if (tcp_is_sack(tp)) tcp_sack_reset(&tp->rx_opt); sk_mem_reclaim(sk); if (!sock_flag(sk, SOCK_DEAD)) { sk->sk_state_change(sk); if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); else sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); } } static inline int 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)) { if (before(seq, sp->start_seq)) sp->start_seq = seq; if (after(end_seq, sp->end_seq)) sp->end_seq = end_seq; return 1; } return 0; } static void tcp_dsack_set(struct sock *sk, u32 seq, u32 end_seq) { struct tcp_sock *tp = tcp_sk(sk); if (tcp_is_sack(tp) && sysctl_tcp_dsack) { int mib_idx; if (before(seq, tp->rcv_nxt)) mib_idx = LINUX_MIB_TCPDSACKOLDSENT; else mib_idx = LINUX_MIB_TCPDSACKOFOSENT; NET_INC_STATS_BH(sock_net(sk), mib_idx); tp->rx_opt.dsack = 1; tp->duplicate_sack[0].start_seq = seq; tp->duplicate_sack[0].end_seq = end_seq; } } static void tcp_dsack_extend(struct sock *sk, u32 seq, u32 end_seq) { struct tcp_sock *tp = tcp_sk(sk); if (!tp->rx_opt.dsack) tcp_dsack_set(sk, seq, end_seq); else tcp_sack_extend(tp->duplicate_sack, seq, end_seq); } static void tcp_send_dupack(struct sock *sk, const struct sk_buff *skb) { struct tcp_sock *tp = tcp_sk(sk); if (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq && before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) { NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKLOST); tcp_enter_quickack_mode(sk); if (tcp_is_sack(tp) && sysctl_tcp_dsack) { u32 end_seq = TCP_SKB_CB(skb)->end_seq; if (after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt)) end_seq = tp->rcv_nxt; tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, end_seq); } } tcp_send_ack(sk); } static void tcp_sack_maybe_coalesce(struct tcp_sock *tp) { int this_sack; struct tcp_sack_block *sp = &tp->selective_acks[0]; struct tcp_sack_block *swalk = sp + 1; for (this_sack = 1; this_sack < tp->rx_opt.num_sacks;) { if (tcp_sack_extend(sp, swalk->start_seq, swalk->end_seq)) { int i; tp->rx_opt.num_sacks--; for (i = this_sack; i < tp->rx_opt.num_sacks; i++) sp[i] = sp[i + 1]; continue; } this_sack++, swalk++; } } static void tcp_sack_new_ofo_skb(struct sock *sk, u32 seq, u32 end_seq) { struct tcp_sock *tp = tcp_sk(sk); struct tcp_sack_block *sp = &tp->selective_acks[0]; int cur_sacks = tp->rx_opt.num_sacks; int this_sack; if (!cur_sacks) goto new_sack; for (this_sack = 0; this_sack < cur_sacks; this_sack++, sp++) { if (tcp_sack_extend(sp, seq, end_seq)) { for (; this_sack > 0; this_sack--, sp--) swap(*sp, *(sp - 1)); if (cur_sacks > 1) tcp_sack_maybe_coalesce(tp); return; } } if (this_sack >= TCP_NUM_SACKS) { this_sack--; tp->rx_opt.num_sacks--; sp--; } for (; this_sack > 0; this_sack--, sp--) *sp = *(sp - 1); new_sack: sp->start_seq = seq; sp->end_seq = end_seq; tp->rx_opt.num_sacks++; } static void tcp_sack_remove(struct tcp_sock *tp) { struct tcp_sack_block *sp = &tp->selective_acks[0]; int num_sacks = tp->rx_opt.num_sacks; int this_sack; if (skb_queue_empty(&tp->out_of_order_queue)) { tp->rx_opt.num_sacks = 0; return; } for (this_sack = 0; this_sack < num_sacks;) { if (!before(tp->rcv_nxt, sp->start_seq)) { int i; WARN_ON(before(tp->rcv_nxt, sp->end_seq)); for (i=this_sack+1; i < num_sacks; i++) tp->selective_acks[i-1] = tp->selective_acks[i]; num_sacks--; continue; } this_sack++; sp++; } tp->rx_opt.num_sacks = num_sacks; } static void tcp_ofo_queue(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); __u32 dsack_high = tp->rcv_nxt; struct sk_buff *skb; while ((skb = skb_peek(&tp->out_of_order_queue)) != NULL) { if (after(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) break; if (before(TCP_SKB_CB(skb)->seq, dsack_high)) { __u32 dsack = dsack_high; if (before(TCP_SKB_CB(skb)->end_seq, dsack_high)) dsack_high = TCP_SKB_CB(skb)->end_seq; tcp_dsack_extend(sk, TCP_SKB_CB(skb)->seq, dsack); } if (!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt)) { SOCK_DEBUG(sk, "ofo packet was already received\n"); __skb_unlink(skb, &tp->out_of_order_queue); __kfree_skb(skb); continue; } SOCK_DEBUG(sk, "ofo requeuing : rcv_next %X seq %X - %X\n", tp->rcv_nxt, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq); __skb_unlink(skb, &tp->out_of_order_queue); __skb_queue_tail(&sk->sk_receive_queue, skb); tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq; if (tcp_hdr(skb)->fin) tcp_fin(sk); } } static int 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) { if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || !sk_rmem_schedule(sk, size)) { if (tcp_prune_queue(sk) < 0) return -1; if (!sk_rmem_schedule(sk, size)) { if (!tcp_prune_ofo_queue(sk)) return -1; if (!sk_rmem_schedule(sk, size)) return -1; } } return 0; } static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) { struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb1; u32 seq, end_seq; TCP_ECN_check_ce(tp, skb); if (tcp_try_rmem_schedule(sk, skb->truesize)) { __kfree_skb(skb); return; } tp->pred_flags = 0; inet_csk_schedule_ack(sk); SOCK_DEBUG(sk, "out of order segment: rcv_next %X seq %X - %X\n", tp->rcv_nxt, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq); skb1 = skb_peek_tail(&tp->out_of_order_queue); if (!skb1) { if (tcp_is_sack(tp)) { tp->rx_opt.num_sacks = 1; tp->selective_acks[0].start_seq = TCP_SKB_CB(skb)->seq; tp->selective_acks[0].end_seq = TCP_SKB_CB(skb)->end_seq; } __skb_queue_head(&tp->out_of_order_queue, skb); goto end; } seq = TCP_SKB_CB(skb)->seq; end_seq = TCP_SKB_CB(skb)->end_seq; if (seq == TCP_SKB_CB(skb1)->end_seq) { 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 { __skb_queue_after(&tp->out_of_order_queue, skb1, skb); } if (!tp->rx_opt.num_sacks || tp->selective_acks[0].end_seq != seq) goto add_sack; tp->selective_acks[0].end_seq = end_seq; goto end; } while (1) { if (!after(TCP_SKB_CB(skb1)->seq, seq)) break; if (skb_queue_is_first(&tp->out_of_order_queue, skb1)) { skb1 = NULL; break; } skb1 = skb_queue_prev(&tp->out_of_order_queue, skb1); } if (skb1 && before(seq, TCP_SKB_CB(skb1)->end_seq)) { if (!after(end_seq, TCP_SKB_CB(skb1)->end_seq)) { __kfree_skb(skb); skb = NULL; tcp_dsack_set(sk, seq, end_seq); goto add_sack; } if (after(seq, TCP_SKB_CB(skb1)->seq)) { tcp_dsack_set(sk, seq, TCP_SKB_CB(skb1)->end_seq); } else { if (skb_queue_is_first(&tp->out_of_order_queue, skb1)) skb1 = NULL; else skb1 = skb_queue_prev( &tp->out_of_order_queue, skb1); } } if (!skb1) __skb_queue_head(&tp->out_of_order_queue, skb); else __skb_queue_after(&tp->out_of_order_queue, skb1, skb); while (!skb_queue_is_last(&tp->out_of_order_queue, skb)) { skb1 = skb_queue_next(&tp->out_of_order_queue, skb); if (!after(end_seq, TCP_SKB_CB(skb1)->seq)) break; if (before(end_seq, TCP_SKB_CB(skb1)->end_seq)) { tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq, end_seq); break; } __skb_unlink(skb1, &tp->out_of_order_queue); tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq, TCP_SKB_CB(skb1)->end_seq); __kfree_skb(skb1); } add_sack: if (tcp_is_sack(tp)) tcp_sack_new_ofo_skb(sk, seq, end_seq); end: if (skb) skb_set_owner_r(skb, sk); } 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; if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) goto drop; skb_dst_drop(skb); __skb_pull(skb, th->doff * 4); TCP_ECN_accept_cwr(tp, skb); tp->rx_opt.dsack = 0; if (TCP_SKB_CB(skb)->seq == tp->rcv_nxt) { if (tcp_receive_window(tp) == 0) goto out_of_window; if (tp->ucopy.task == current && tp->copied_seq == tp->rcv_nxt && tp->ucopy.len && sock_owned_by_user(sk) && !tp->urg_data) { int chunk = min_t(unsigned int, skb->len, tp->ucopy.len); __set_current_state(TASK_RUNNING); local_bh_enable(); if (!skb_copy_datagram_iovec(skb, 0, tp->ucopy.iov, chunk)) { tp->ucopy.len -= chunk; tp->copied_seq += chunk; eaten = (chunk == skb->len); tcp_rcv_space_adjust(sk); } local_bh_disable(); } if (eaten <= 0) { queue_and_out: if (eaten < 0 && tcp_try_rmem_schedule(sk, skb->truesize)) goto drop; skb_set_owner_r(skb, sk); __skb_queue_tail(&sk->sk_receive_queue, skb); } tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq; if (skb->len) tcp_event_data_recv(sk, skb); if (th->fin) tcp_fin(sk); if (!skb_queue_empty(&tp->out_of_order_queue)) { tcp_ofo_queue(sk); if (skb_queue_empty(&tp->out_of_order_queue)) inet_csk(sk)->icsk_ack.pingpong = 0; } if (tp->rx_opt.num_sacks) tcp_sack_remove(tp); tcp_fast_path_check(sk); if (eaten > 0) __kfree_skb(skb); else if (!sock_flag(sk, SOCK_DEAD)) sk->sk_data_ready(sk, 0); return; } if (!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt)) { NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKLOST); tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq); out_of_window: tcp_enter_quickack_mode(sk); inet_csk_schedule_ack(sk); drop: __kfree_skb(skb); return; } if (!before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt + tcp_receive_window(tp))) goto out_of_window; tcp_enter_quickack_mode(sk); if (before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) { SOCK_DEBUG(sk, "partial packet: rcv_next %X seq %X - %X\n", tp->rcv_nxt, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq); tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, tp->rcv_nxt); if (!tcp_receive_window(tp)) goto out_of_window; goto queue_and_out; } tcp_data_queue_ofo(sk, skb); } static struct sk_buff *tcp_collapse_one(struct sock *sk, struct sk_buff *skb, struct sk_buff_head *list) { struct sk_buff *next = NULL; if (!skb_queue_is_last(list, skb)) next = skb_queue_next(list, skb); __skb_unlink(skb, list); __kfree_skb(skb); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPRCVCOLLAPSED); return next; } static void tcp_collapse(struct sock *sk, struct sk_buff_head *list, struct sk_buff *head, struct sk_buff *tail, u32 start, u32 end) { struct sk_buff *skb, *n; bool end_of_skbs; skb = head; restart: end_of_skbs = true; skb_queue_walk_from_safe(list, skb, n) { if (skb == tail) break; if (!before(start, TCP_SKB_CB(skb)->end_seq)) { skb = tcp_collapse_one(sk, skb, list); if (!skb) break; goto restart; } if (!tcp_hdr(skb)->syn && !tcp_hdr(skb)->fin && (tcp_win_from_space(skb->truesize) > skb->len || before(TCP_SKB_CB(skb)->seq, start))) { end_of_skbs = false; break; } if (!skb_queue_is_last(list, skb)) { struct sk_buff *next = skb_queue_next(list, skb); if (next != tail && TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(next)->seq) { end_of_skbs = false; break; } } start = TCP_SKB_CB(skb)->end_seq; } if (end_of_skbs || tcp_hdr(skb)->syn || tcp_hdr(skb)->fin) return; while (before(start, end)) { struct sk_buff *nskb; unsigned int header = skb_headroom(skb); int copy = SKB_MAX_ORDER(header, 0); if (copy < 0) return; if (end - start < copy) copy = end - start; nskb = alloc_skb(copy + header, GFP_ATOMIC); if (!nskb) return; skb_set_mac_header(nskb, skb_mac_header(skb) - skb->head); skb_set_network_header(nskb, (skb_network_header(skb) - skb->head)); skb_set_transport_header(nskb, (skb_transport_header(skb) - skb->head)); skb_reserve(nskb, header); memcpy(nskb->head, skb->head, header); memcpy(nskb->cb, skb->cb, sizeof(skb->cb)); TCP_SKB_CB(nskb)->seq = TCP_SKB_CB(nskb)->end_seq = start; __skb_queue_before(list, skb, nskb); skb_set_owner_r(nskb, sk); while (copy > 0) { int offset = start - TCP_SKB_CB(skb)->seq; int size = TCP_SKB_CB(skb)->end_seq - start; BUG_ON(offset < 0); if (size > 0) { size = min(copy, size); if (skb_copy_bits(skb, offset, skb_put(nskb, size), size)) BUG(); TCP_SKB_CB(nskb)->end_seq += size; copy -= size; start += size; } if (!before(start, TCP_SKB_CB(skb)->end_seq)) { skb = tcp_collapse_one(sk, skb, list); if (!skb || skb == tail || tcp_hdr(skb)->syn || tcp_hdr(skb)->fin) return; } } } } static void tcp_collapse_ofo_queue(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb = skb_peek(&tp->out_of_order_queue); struct sk_buff *head; u32 start, end; if (skb == NULL) return; start = TCP_SKB_CB(skb)->seq; end = TCP_SKB_CB(skb)->end_seq; head = skb; for (;;) { struct sk_buff *next = NULL; if (!skb_queue_is_last(&tp->out_of_order_queue, skb)) next = skb_queue_next(&tp->out_of_order_queue, skb); skb = next; if (!skb || after(TCP_SKB_CB(skb)->seq, end) || before(TCP_SKB_CB(skb)->end_seq, start)) { tcp_collapse(sk, &tp->out_of_order_queue, head, skb, start, end); head = skb; if (!skb) break; start = TCP_SKB_CB(skb)->seq; end = TCP_SKB_CB(skb)->end_seq; } else { if (before(TCP_SKB_CB(skb)->seq, start)) start = TCP_SKB_CB(skb)->seq; if (after(TCP_SKB_CB(skb)->end_seq, end)) end = TCP_SKB_CB(skb)->end_seq; } } } static int tcp_prune_ofo_queue(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); int res = 0; if (!skb_queue_empty(&tp->out_of_order_queue)) { NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_OFOPRUNED); __skb_queue_purge(&tp->out_of_order_queue); if (tp->rx_opt.sack_ok) tcp_sack_reset(&tp->rx_opt); sk_mem_reclaim(sk); res = 1; } return res; } static int tcp_prune_queue(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); SOCK_DEBUG(sk, "prune_queue: c=%x\n", tp->copied_seq); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PRUNECALLED); if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) tcp_clamp_window(sk); else if (sk_under_memory_pressure(sk)) tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U * tp->advmss); tcp_collapse_ofo_queue(sk); if (!skb_queue_empty(&sk->sk_receive_queue)) tcp_collapse(sk, &sk->sk_receive_queue, skb_peek(&sk->sk_receive_queue), NULL, tp->copied_seq, tp->rcv_nxt); sk_mem_reclaim(sk); if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf) return 0; tcp_prune_ofo_queue(sk); if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf) return 0; NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_RCVPRUNED); tp->pred_flags = 0; return -1; } void tcp_cwnd_application_limited(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); if (inet_csk(sk)->icsk_ca_state == TCP_CA_Open && sk->sk_socket && !test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) { u32 init_win = tcp_init_cwnd(tp, __sk_dst_get(sk)); u32 win_used = max(tp->snd_cwnd_used, init_win); if (win_used < tp->snd_cwnd) { tp->snd_ssthresh = tcp_current_ssthresh(sk); tp->snd_cwnd = (tp->snd_cwnd + win_used) >> 1; } tp->snd_cwnd_used = 0; } tp->snd_cwnd_stamp = tcp_time_stamp; } static int tcp_should_expand_sndbuf(const struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); if (sk->sk_userlocks & SOCK_SNDBUF_LOCK) return 0; if (sk_under_memory_pressure(sk)) return 0; if (sk_memory_allocated(sk) >= sk_prot_mem_limits(sk, 0)) return 0; if (tp->packets_out >= tp->snd_cwnd) return 0; return 1; } static void tcp_new_space(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); if (tcp_should_expand_sndbuf(sk)) { int sndmem = SKB_TRUESIZE(max_t(u32, tp->rx_opt.mss_clamp, tp->mss_cache) + MAX_TCP_HEADER); int demanded = max_t(unsigned int, tp->snd_cwnd, tp->reordering + 1); sndmem *= 2 * demanded; if (sndmem > sk->sk_sndbuf) sk->sk_sndbuf = min(sndmem, sysctl_tcp_wmem[2]); tp->snd_cwnd_stamp = tcp_time_stamp; } sk->sk_write_space(sk); } static void tcp_check_space(struct sock *sk) { if (sock_flag(sk, SOCK_QUEUE_SHRUNK)) { sock_reset_flag(sk, SOCK_QUEUE_SHRUNK); if (sk->sk_socket && test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) tcp_new_space(sk); } } static inline void tcp_data_snd_check(struct sock *sk) { tcp_push_pending_frames(sk); tcp_check_space(sk); } static void __tcp_ack_snd_check(struct sock *sk, int ofo_possible) { struct tcp_sock *tp = tcp_sk(sk); if (((tp->rcv_nxt - tp->rcv_wup) > inet_csk(sk)->icsk_ack.rcv_mss && __tcp_select_window(sk) >= tp->rcv_wnd) || tcp_in_quickack_mode(sk) || (ofo_possible && skb_peek(&tp->out_of_order_queue))) { tcp_send_ack(sk); } else { tcp_send_delayed_ack(sk); } } static inline void tcp_ack_snd_check(struct sock *sk) { if (!inet_csk_ack_scheduled(sk)) { return; } __tcp_ack_snd_check(sk, 1); } static void tcp_check_urg(struct sock *sk, const struct tcphdr *th) { struct tcp_sock *tp = tcp_sk(sk); u32 ptr = ntohs(th->urg_ptr); if (ptr && !sysctl_tcp_stdurg) ptr--; ptr += ntohl(th->seq); if (after(tp->copied_seq, ptr)) return; if (before(ptr, tp->rcv_nxt)) return; if (tp->urg_data && !after(ptr, tp->urg_seq)) return; sk_send_sigurg(sk); if (tp->urg_seq == tp->copied_seq && tp->urg_data && !sock_flag(sk, SOCK_URGINLINE) && tp->copied_seq != tp->rcv_nxt) { struct sk_buff *skb = skb_peek(&sk->sk_receive_queue); tp->copied_seq++; if (skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq)) { __skb_unlink(skb, &sk->sk_receive_queue); __kfree_skb(skb); } } tp->urg_data = TCP_URG_NOTYET; tp->urg_seq = ptr; tp->pred_flags = 0; } static void tcp_urg(struct sock *sk, struct sk_buff *skb, const struct tcphdr *th) { struct tcp_sock *tp = tcp_sk(sk); if (th->urg) tcp_check_urg(sk, th); if (tp->urg_data == TCP_URG_NOTYET) { u32 ptr = tp->urg_seq - ntohl(th->seq) + (th->doff * 4) - th->syn; if (ptr < skb->len) { u8 tmp; if (skb_copy_bits(skb, ptr, &tmp, 1)) BUG(); tp->urg_data = TCP_URG_VALID | tmp; if (!sock_flag(sk, SOCK_DEAD)) sk->sk_data_ready(sk, 0); } } } static int tcp_copy_to_iovec(struct sock *sk, struct sk_buff *skb, int hlen) { struct tcp_sock *tp = tcp_sk(sk); int chunk = skb->len - hlen; int err; local_bh_enable(); if (skb_csum_unnecessary(skb)) err = skb_copy_datagram_iovec(skb, hlen, tp->ucopy.iov, chunk); else err = skb_copy_and_csum_datagram_iovec(skb, hlen, tp->ucopy.iov); if (!err) { tp->ucopy.len -= chunk; tp->copied_seq += chunk; tcp_rcv_space_adjust(sk); } local_bh_disable(); return err; } static __sum16 __tcp_checksum_complete_user(struct sock *sk, struct sk_buff *skb) { __sum16 result; if (sock_owned_by_user(sk)) { local_bh_enable(); result = __tcp_checksum_complete(skb); local_bh_disable(); } else { result = __tcp_checksum_complete(skb); } return result; } static inline int tcp_checksum_complete_user(struct sock *sk, struct sk_buff *skb) { return !skb_csum_unnecessary(skb) && __tcp_checksum_complete_user(sk, skb); } #ifdef CONFIG_NET_DMA static int 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; if (tp->ucopy.wakeup) return 0; if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list) tp->ucopy.dma_chan = net_dma_find_channel(); if (tp->ucopy.dma_chan && skb_csum_unnecessary(skb)) { dma_cookie = dma_skb_copy_datagram_iovec(tp->ucopy.dma_chan, skb, hlen, tp->ucopy.iov, chunk, tp->ucopy.pinned_list); if (dma_cookie < 0) goto out; tp->ucopy.dma_cookie = dma_cookie; copied_early = 1; tp->ucopy.len -= chunk; tp->copied_seq += chunk; tcp_rcv_space_adjust(sk); if ((tp->ucopy.len == 0) || (tcp_flag_word(tcp_hdr(skb)) & TCP_FLAG_PSH) || (atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1))) { tp->ucopy.wakeup = 1; sk->sk_data_ready(sk, 0); } } else if (chunk > 0) { tp->ucopy.wakeup = 1; sk->sk_data_ready(sk, 0); } out: return copied_early; } #endif static int tcp_validate_incoming(struct sock *sk, struct sk_buff *skb, const struct tcphdr *th, int syn_inerr) { const u8 *hash_location; struct tcp_sock *tp = tcp_sk(sk); if (tcp_fast_parse_options(skb, th, tp, &hash_location) && tp->rx_opt.saw_tstamp && tcp_paws_discard(sk, skb)) { if (!th->rst) { NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSESTABREJECTED); tcp_send_dupack(sk, skb); goto discard; } } if (!tcp_sequence(tp, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq)) { if (!th->rst) tcp_send_dupack(sk, skb); goto discard; } if (th->rst) { tcp_reset(sk); goto discard; } tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq); if (th->syn && !before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) { if (syn_inerr) TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONSYN); tcp_reset(sk); return -1; } return 1; discard: __kfree_skb(skb); return 0; } int tcp_rcv_established(struct sock *sk, struct sk_buff *skb, const struct tcphdr *th, unsigned int len) { struct tcp_sock *tp = tcp_sk(sk); int res; tp->rx_opt.saw_tstamp = 0; if ((tcp_flag_word(th) & TCP_HP_BITS) == tp->pred_flags && TCP_SKB_CB(skb)->seq == tp->rcv_nxt && !after(TCP_SKB_CB(skb)->ack_seq, tp->snd_nxt)) { int tcp_header_len = tp->tcp_header_len; if (tcp_header_len == sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED) { if (!tcp_parse_aligned_timestamp(tp, th)) goto slow_path; if ((s32)(tp->rx_opt.rcv_tsval - tp->rx_opt.ts_recent) < 0) goto slow_path; } if (len <= tcp_header_len) { if (len == tcp_header_len) { if (tcp_header_len == (sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED) && tp->rcv_nxt == tp->rcv_wup) tcp_store_ts_recent(tp); tcp_ack(sk, skb, 0); __kfree_skb(skb); tcp_data_snd_check(sk); return 0; } else { TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS); goto discard; } } else { int eaten = 0; int copied_early = 0; if (tp->copied_seq == tp->rcv_nxt && len - tcp_header_len <= tp->ucopy.len) { #ifdef CONFIG_NET_DMA if (tp->ucopy.task == current && sock_owned_by_user(sk) && tcp_dma_try_early_copy(sk, skb, tcp_header_len)) { copied_early = 1; eaten = 1; } #endif if (tp->ucopy.task == current && sock_owned_by_user(sk) && !copied_early) { __set_current_state(TASK_RUNNING); if (!tcp_copy_to_iovec(sk, skb, tcp_header_len)) eaten = 1; } if (eaten) { if (tcp_header_len == (sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED) && tp->rcv_nxt == tp->rcv_wup) tcp_store_ts_recent(tp); tcp_rcv_rtt_measure_ts(sk, skb); __skb_pull(skb, tcp_header_len); tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq; NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPHPHITSTOUSER); } if (copied_early) tcp_cleanup_rbuf(sk, skb->len); } if (!eaten) { if (tcp_checksum_complete_user(sk, skb)) goto csum_error; if (tcp_header_len == (sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED) && tp->rcv_nxt == tp->rcv_wup) tcp_store_ts_recent(tp); tcp_rcv_rtt_measure_ts(sk, skb); if ((int)skb->truesize > sk->sk_forward_alloc) goto step5; NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPHPHITS); __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; } tcp_event_data_recv(sk, skb); if (TCP_SKB_CB(skb)->ack_seq != tp->snd_una) { tcp_ack(sk, skb, FLAG_DATA); tcp_data_snd_check(sk); if (!inet_csk_ack_scheduled(sk)) goto no_ack; } if (!copied_early || tp->rcv_nxt != tp->rcv_wup) __tcp_ack_snd_check(sk, 0); no_ack: #ifdef CONFIG_NET_DMA if (copied_early) __skb_queue_tail(&sk->sk_async_wait_queue, skb); else #endif if (eaten) __kfree_skb(skb); else sk->sk_data_ready(sk, 0); return 0; } } slow_path: if (len < (th->doff << 2) || tcp_checksum_complete_user(sk, skb)) goto csum_error; res = tcp_validate_incoming(sk, skb, th, 1); if (res <= 0) return -res; step5: if (th->ack && tcp_ack(sk, skb, FLAG_SLOWPATH) < 0) goto discard; tcp_rcv_rtt_measure_ts(sk, skb); tcp_urg(sk, skb, th); tcp_data_queue(sk, skb); tcp_data_snd_check(sk); tcp_ack_snd_check(sk); return 0; csum_error: TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS); discard: __kfree_skb(skb); return 0; } EXPORT_SYMBOL(tcp_rcv_established); static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, const struct tcphdr *th, unsigned int len) { const u8 *hash_location; struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); struct tcp_cookie_values *cvp = tp->cookie_values; int saved_clamp = tp->rx_opt.mss_clamp; tcp_parse_options(skb, &tp->rx_opt, &hash_location, 0); if (th->ack) { if (TCP_SKB_CB(skb)->ack_seq != tp->snd_nxt) goto reset_and_undo; if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr && !between(tp->rx_opt.rcv_tsecr, tp->retrans_stamp, tcp_time_stamp)) { NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSACTIVEREJECTED); goto reset_and_undo; } if (th->rst) { tcp_reset(sk); goto discard; } if (!th->syn) goto discard_and_undo; TCP_ECN_rcv_synack(tp, th); tp->snd_wl1 = TCP_SKB_CB(skb)->seq; tcp_ack(sk, skb, FLAG_SLOWPATH); tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1; tp->rcv_wup = TCP_SKB_CB(skb)->seq + 1; tp->snd_wnd = ntohs(th->window); tcp_init_wl(tp, TCP_SKB_CB(skb)->seq); if (!tp->rx_opt.wscale_ok) { tp->rx_opt.snd_wscale = tp->rx_opt.rcv_wscale = 0; tp->window_clamp = min(tp->window_clamp, 65535U); } if (tp->rx_opt.saw_tstamp) { tp->rx_opt.tstamp_ok = 1; tp->tcp_header_len = sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED; tp->advmss -= TCPOLEN_TSTAMP_ALIGNED; tcp_store_ts_recent(tp); } else { tp->tcp_header_len = sizeof(struct tcphdr); } if (tcp_is_sack(tp) && sysctl_tcp_fack) tcp_enable_fack(tp); tcp_mtup_init(sk); tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); tcp_initialize_rcv_mss(sk); tp->copied_seq = tp->rcv_nxt; if (cvp != NULL && cvp->cookie_pair_size > 0 && tp->rx_opt.cookie_plus > 0) { int cookie_size = tp->rx_opt.cookie_plus - TCPOLEN_COOKIE_BASE; int cookie_pair_size = cookie_size + cvp->cookie_desired; if (sizeof(cvp->cookie_pair) >= cookie_pair_size) { memcpy(&cvp->cookie_pair[cvp->cookie_desired], hash_location, cookie_size); cvp->cookie_pair_size = cookie_pair_size; } } smp_mb(); tcp_set_state(sk, TCP_ESTABLISHED); security_inet_conn_established(sk, skb); icsk->icsk_af_ops->rebuild_header(sk); tcp_init_metrics(sk); tcp_init_congestion_control(sk); 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); } if (sk->sk_write_pending || icsk->icsk_accept_queue.rskq_defer_accept || icsk->icsk_ack.pingpong) { 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); discard: __kfree_skb(skb); return 0; } else { tcp_send_ack(sk); } return -1; } if (th->rst) { goto discard_and_undo; } if (tp->rx_opt.ts_recent_stamp && tp->rx_opt.saw_tstamp && tcp_paws_reject(&tp->rx_opt, 0)) goto discard_and_undo; if (th->syn) { tcp_set_state(sk, TCP_SYN_RECV); if (tp->rx_opt.saw_tstamp) { tp->rx_opt.tstamp_ok = 1; tcp_store_ts_recent(tp); tp->tcp_header_len = sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED; } else { tp->tcp_header_len = sizeof(struct tcphdr); } tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1; tp->rcv_wup = TCP_SKB_CB(skb)->seq + 1; tp->snd_wnd = ntohs(th->window); tp->snd_wl1 = TCP_SKB_CB(skb)->seq; tp->max_window = tp->snd_wnd; TCP_ECN_rcv_syn(tp, th); tcp_mtup_init(sk); tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); tcp_initialize_rcv_mss(sk); tcp_send_synack(sk); #if 0 return -1; #else goto discard; #endif } discard_and_undo: tcp_clear_options(&tp->rx_opt); tp->rx_opt.mss_clamp = saved_clamp; goto discard; reset_and_undo: tcp_clear_options(&tp->rx_opt); tp->rx_opt.mss_clamp = saved_clamp; return 1; } int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, const struct tcphdr *th, unsigned int len) { struct tcp_sock *tp = tcp_sk(sk); struct inet_connection_sock *icsk = inet_csk(sk); int queued = 0; int res; tp->rx_opt.saw_tstamp = 0; switch (sk->sk_state) { case TCP_CLOSE: goto discard; case TCP_LISTEN: if (th->ack) return 1; if (th->rst) goto discard; if (th->syn) { if (th->fin) goto discard; if (icsk->icsk_af_ops->conn_request(sk, skb) < 0) return 1; kfree_skb(skb); return 0; } goto discard; case TCP_SYN_SENT: queued = tcp_rcv_synsent_state_process(sk, skb, th, len); if (queued >= 0) return queued; tcp_urg(sk, skb, th); __kfree_skb(skb); tcp_data_snd_check(sk); return 0; } res = tcp_validate_incoming(sk, skb, th, 0); if (res <= 0) return -res; if (th->ack) { int acceptable = tcp_ack(sk, skb, FLAG_SLOWPATH) > 0; switch (sk->sk_state) { case TCP_SYN_RECV: if (acceptable) { tp->copied_seq = tp->rcv_nxt; smp_mb(); tcp_set_state(sk, TCP_ESTABLISHED); sk->sk_state_change(sk); if (sk->sk_socket) sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); tp->snd_una = TCP_SKB_CB(skb)->ack_seq; tp->snd_wnd = ntohs(th->window) << tp->rx_opt.snd_wscale; tcp_init_wl(tp, TCP_SKB_CB(skb)->seq); if (tp->rx_opt.tstamp_ok) tp->advmss -= TCPOLEN_TSTAMP_ALIGNED; icsk->icsk_af_ops->rebuild_header(sk); tcp_init_metrics(sk); tcp_init_congestion_control(sk); tp->lsndtime = tcp_time_stamp; tcp_mtup_init(sk); tcp_initialize_rcv_mss(sk); tcp_init_buffer_space(sk); tcp_fast_path_on(tp); } else { return 1; } break; case TCP_FIN_WAIT1: if (tp->snd_una == tp->write_seq) { tcp_set_state(sk, TCP_FIN_WAIT2); sk->sk_shutdown |= SEND_SHUTDOWN; dst_confirm(__sk_dst_get(sk)); if (!sock_flag(sk, SOCK_DEAD)) sk->sk_state_change(sk); else { int tmo; if (tp->linger2 < 0 || (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq && after(TCP_SKB_CB(skb)->end_seq - th->fin, tp->rcv_nxt))) { tcp_done(sk); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONDATA); return 1; } tmo = tcp_fin_time(sk); if (tmo > TCP_TIMEWAIT_LEN) { inet_csk_reset_keepalive_timer(sk, tmo - TCP_TIMEWAIT_LEN); } else if (th->fin || sock_owned_by_user(sk)) { inet_csk_reset_keepalive_timer(sk, tmo); } else { tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); goto discard; } } } break; case TCP_CLOSING: if (tp->snd_una == tp->write_seq) { tcp_time_wait(sk, TCP_TIME_WAIT, 0); goto discard; } break; case TCP_LAST_ACK: if (tp->snd_una == tp->write_seq) { tcp_update_metrics(sk); tcp_done(sk); goto discard; } break; } } else goto discard; tcp_urg(sk, skb, th); switch (sk->sk_state) { case TCP_CLOSE_WAIT: case TCP_CLOSING: case TCP_LAST_ACK: if (!before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) break; case TCP_FIN_WAIT1: case TCP_FIN_WAIT2: if (sk->sk_shutdown & RCV_SHUTDOWN) { if (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq && after(TCP_SKB_CB(skb)->end_seq - th->fin, tp->rcv_nxt)) { NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONDATA); tcp_reset(sk); return 1; } } case TCP_ESTABLISHED: tcp_data_queue(sk, skb); queued = 1; break; } if (sk->sk_state != TCP_CLOSE) { tcp_data_snd_check(sk); tcp_ack_snd_check(sk); } if (!queued) { discard: __kfree_skb(skb); } return 0; } EXPORT_SYMBOL(tcp_rcv_state_process);