diff options
| -rw-r--r-- | include/linux/tcp.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/snmp.h | 1 | ||||
| -rw-r--r-- | net/ipv4/proc.c | 1 | ||||
| -rw-r--r-- | net/ipv4/tcp_input.c | 39 | ||||
| -rw-r--r-- | net/ipv4/tcp_minisocks.c | 1 | ||||
| -rw-r--r-- | net/ipv4/tcp_output.c | 9 | ||||
| -rw-r--r-- | net/ipv4/tcp_timer.c | 2 |
7 files changed, 54 insertions, 0 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 01860d74555..763c108ee03 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -204,6 +204,7 @@ struct tcp_sock { syn_data:1, /* SYN includes data */ syn_fastopen:1, /* SYN includes Fast Open option */ syn_data_acked:1;/* data in SYN is acked by SYN-ACK */ + u32 tlp_high_seq; /* snd_nxt at the time of TLP retransmit. */ /* RTT measurement */ u32 srtt; /* smoothed round trip time << 3 */ diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h index 290bed6b085..e00013a1deb 100644 --- a/include/uapi/linux/snmp.h +++ b/include/uapi/linux/snmp.h @@ -203,6 +203,7 @@ enum LINUX_MIB_TCPSLOWSTARTRETRANS, /* TCPSlowStartRetrans */ LINUX_MIB_TCPTIMEOUTS, /* TCPTimeouts */ LINUX_MIB_TCPLOSSPROBES, /* TCPLossProbes */ + LINUX_MIB_TCPLOSSPROBERECOVERY, /* TCPLossProbeRecovery */ LINUX_MIB_TCPRENORECOVERYFAIL, /* TCPRenoRecoveryFail */ LINUX_MIB_TCPSACKRECOVERYFAIL, /* TCPSackRecoveryFail */ LINUX_MIB_TCPSCHEDULERFAILED, /* TCPSchedulerFailed */ diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index 4c35911d935..b6f2ea17489 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -225,6 +225,7 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TCPSlowStartRetrans", LINUX_MIB_TCPSLOWSTARTRETRANS), SNMP_MIB_ITEM("TCPTimeouts", LINUX_MIB_TCPTIMEOUTS), SNMP_MIB_ITEM("TCPLossProbes", LINUX_MIB_TCPLOSSPROBES), + SNMP_MIB_ITEM("TCPLossProbeRecovery", LINUX_MIB_TCPLOSSPROBERECOVERY), SNMP_MIB_ITEM("TCPRenoRecoveryFail", LINUX_MIB_TCPRENORECOVERYFAIL), SNMP_MIB_ITEM("TCPSackRecoveryFail", LINUX_MIB_TCPSACKRECOVERYFAIL), SNMP_MIB_ITEM("TCPSchedulerFailed", LINUX_MIB_TCPSCHEDULERFAILED), diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index b794f89ac1f..836d74dd018 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2682,6 +2682,7 @@ static void tcp_init_cwnd_reduction(struct sock *sk, const bool set_ssthresh) struct tcp_sock *tp = tcp_sk(sk); tp->high_seq = tp->snd_nxt; + tp->tlp_high_seq = 0; tp->snd_cwnd_cnt = 0; tp->prior_cwnd = tp->snd_cwnd; tp->prr_delivered = 0; @@ -3569,6 +3570,38 @@ static void tcp_send_challenge_ack(struct sock *sk) } } +/* This routine deals with acks during a TLP episode. + * Ref: loss detection algorithm in draft-dukkipati-tcpm-tcp-loss-probe. + */ +static void tcp_process_tlp_ack(struct sock *sk, u32 ack, int flag) +{ + struct tcp_sock *tp = tcp_sk(sk); + bool is_tlp_dupack = (ack == tp->tlp_high_seq) && + !(flag & (FLAG_SND_UNA_ADVANCED | + FLAG_NOT_DUP | FLAG_DATA_SACKED)); + + /* Mark the end of TLP episode on receiving TLP dupack or when + * ack is after tlp_high_seq. + */ + if (is_tlp_dupack) { + tp->tlp_high_seq = 0; + return; + } + + if (after(ack, tp->tlp_high_seq)) { + tp->tlp_high_seq = 0; + /* Don't reduce cwnd if DSACK arrives for TLP retrans. */ + if (!(flag & FLAG_DSACKING_ACK)) { + tcp_init_cwnd_reduction(sk, true); + tcp_set_ca_state(sk, TCP_CA_CWR); + tcp_end_cwnd_reduction(sk); + tcp_set_ca_state(sk, TCP_CA_Open); + NET_INC_STATS_BH(sock_net(sk), + LINUX_MIB_TCPLOSSPROBERECOVERY); + } + } +} + /* This routine deals with incoming acks, but not outgoing ones. */ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) { @@ -3676,6 +3709,9 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) tcp_cong_avoid(sk, ack, prior_in_flight); } + if (tp->tlp_high_seq) + tcp_process_tlp_ack(sk, ack, flag); + if ((flag & FLAG_FORWARD_PROGRESS) || !(flag & FLAG_NOT_DUP)) { struct dst_entry *dst = __sk_dst_get(sk); if (dst) @@ -3697,6 +3733,9 @@ no_queue: */ if (tcp_send_head(sk)) tcp_ack_probe(sk); + + if (tp->tlp_high_seq) + tcp_process_tlp_ack(sk, ack, flag); return 1; invalid_ack: diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index b83a49cc381..4bdb09fca40 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -440,6 +440,7 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req, newtp->fackets_out = 0; newtp->snd_ssthresh = TCP_INFINITE_SSTHRESH; tcp_enable_early_retrans(newtp); + newtp->tlp_high_seq = 0; /* So many TCP implementations out there (incorrectly) count the * initial SYN frame in their delayed-ACK and congestion control diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index beb63dbc85f..8e7742f0b5d 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2132,6 +2132,7 @@ bool tcp_schedule_loss_probe(struct sock *sk) */ void tcp_send_loss_probe(struct sock *sk) { + struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; int pcount; int mss = tcp_current_mss(sk); @@ -2142,6 +2143,10 @@ void tcp_send_loss_probe(struct sock *sk) goto rearm_timer; } + /* At most one outstanding TLP retransmission. */ + if (tp->tlp_high_seq) + goto rearm_timer; + /* Retransmit last segment. */ skb = tcp_write_queue_tail(sk); if (WARN_ON(!skb)) @@ -2164,6 +2169,10 @@ void tcp_send_loss_probe(struct sock *sk) if (skb->len > 0) err = __tcp_retransmit_skb(sk, skb); + /* Record snd_nxt for loss detection. */ + if (likely(!err)) + tp->tlp_high_seq = tp->snd_nxt; + rearm_timer: inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, inet_csk(sk)->icsk_rto, diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index ecd61d54147..eeccf795e91 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -356,6 +356,8 @@ void tcp_retransmit_timer(struct sock *sk) WARN_ON(tcp_write_queue_empty(sk)); + tp->tlp_high_seq = 0; + if (!tp->snd_wnd && !sock_flag(sk, SOCK_DEAD) && !((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))) { /* Receiver dastardly shrinks window. Our retransmits |