From 2e6052941ae1f2f875d7d9092acb8836af1e0193 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Thu, 2 Aug 2007 19:46:58 -0700 Subject: [PATCH] [TCP]: Also handle snd_una changes in tcp_cwnd_down MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit tcp_cwnd_down must check for it too as it should be conservative in case of collapse stuff and also when receiver is trying to lie (though that wouldn't be very successful/useful anyway). Note: - Separated also is_dupack and do_lost in fast_retransalert * Much cleaner look-and-feel now * This time it really fixes cumulative ACK with many new SACK blocks recovery entry (I claimed this fixes with last patch but it wasn't). TCP will now call tcp_update_scoreboard regardless of is_dupack when in recovery as long as there is enough fackets_out. - Introduce FLAG_SND_UNA_ADVANCED * Some prior_snd_una arguments are unnecessary after it - Added helper FLAG_ANY_PROGRESS to avoid long FLAG...|FLAG... constructs Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 34 ++++++++++++++++++---------------- 1 file changed, 18 insertions(+), 16 deletions(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 378ca8a086a39..c3124e6de1d3b 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -102,11 +102,13 @@ int sysctl_tcp_abc __read_mostly; #define FLAG_DATA_LOST 0x80 /* SACK detected data lossage. */ #define FLAG_SLOWPATH 0x100 /* Do not skip RFC checks for window update.*/ #define FLAG_ONLY_ORIG_SACKED 0x200 /* SACKs only non-rexmit sent before RTO */ +#define FLAG_SND_UNA_ADVANCED 0x400 /* Snd_una was changed (!= FLAG_DATA_ACKED) */ #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 IsReno(tp) ((tp)->rx_opt.sack_ok == 0) #define IsFack(tp) ((tp)->rx_opt.sack_ok & 2) @@ -1856,7 +1858,7 @@ 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_FORWARD_PROGRESS) || + if ((flag&FLAG_ANY_PROGRESS) || (IsReno(tp) && !(flag&FLAG_NOT_DUP))) { tp->snd_cwnd_cnt = decr&1; decr >>= 1; @@ -2107,15 +2109,13 @@ static void tcp_mtup_probe_success(struct sock *sk, struct sk_buff *skb) * tcp_xmit_retransmit_queue(). */ static void -tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una, - int prior_packets, int flag) +tcp_fastretrans_alert(struct sock *sk, int prior_packets, int flag) { struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); - int is_dupack = (tp->snd_una == prior_snd_una && - (!(flag&FLAG_NOT_DUP) || - ((flag&FLAG_DATA_SACKED) && - (tp->fackets_out > tp->reordering)))); + int is_dupack = !(flag&(FLAG_SND_UNA_ADVANCED|FLAG_NOT_DUP)); + int do_lost = is_dupack || ((flag&FLAG_DATA_SACKED) && + (tp->fackets_out > tp->reordering)); /* Some technical things: * 1. Reno does not count dupacks (sacked_out) automatically. */ @@ -2192,14 +2192,14 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una, /* F. Process state. */ switch (icsk->icsk_ca_state) { case TCP_CA_Recovery: - if (prior_snd_una == tp->snd_una) { + if (!(flag & FLAG_SND_UNA_ADVANCED)) { if (IsReno(tp) && is_dupack) tcp_add_reno_sack(sk); } else { int acked = prior_packets - tp->packets_out; if (IsReno(tp)) tcp_remove_reno_sacks(sk, acked); - is_dupack = tcp_try_undo_partial(sk, acked); + do_lost = tcp_try_undo_partial(sk, acked); } break; case TCP_CA_Loss: @@ -2215,7 +2215,7 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una, /* Loss is undone; fall through to processing in Open state. */ default: if (IsReno(tp)) { - if (tp->snd_una != prior_snd_una) + if (flag & FLAG_SND_UNA_ADVANCED) tcp_reset_reno_sack(tp); if (is_dupack) tcp_add_reno_sack(sk); @@ -2264,7 +2264,7 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una, tcp_set_ca_state(sk, TCP_CA_Recovery); } - if (is_dupack || tcp_head_timedout(sk)) + if (do_lost || tcp_head_timedout(sk)) tcp_update_scoreboard(sk); tcp_cwnd_down(sk, flag); tcp_xmit_retransmit_queue(sk); @@ -2684,7 +2684,7 @@ static void tcp_undo_spur_to_response(struct sock *sk, int flag) * to prove that the RTO is indeed spurious. It transfers the control * from F-RTO to the conventional RTO recovery */ -static int tcp_process_frto(struct sock *sk, u32 prior_snd_una, int flag) +static int tcp_process_frto(struct sock *sk, int flag) { struct tcp_sock *tp = tcp_sk(sk); @@ -2704,8 +2704,7 @@ static int tcp_process_frto(struct sock *sk, u32 prior_snd_una, int flag) * ACK isn't duplicate nor advances window, e.g., opposite dir * data, winupdate */ - if ((tp->snd_una == prior_snd_una) && (flag&FLAG_NOT_DUP) && - !(flag&FLAG_FORWARD_PROGRESS)) + if (!(flag&FLAG_ANY_PROGRESS) && (flag&FLAG_NOT_DUP)) return 1; if (!(flag&FLAG_DATA_ACKED)) { @@ -2785,6 +2784,9 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag) if (before(ack, prior_snd_una)) goto old_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; @@ -2837,14 +2839,14 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag) flag |= tcp_clean_rtx_queue(sk, &seq_rtt); if (tp->frto_counter) - frto_cwnd = tcp_process_frto(sk, prior_snd_una, flag); + frto_cwnd = tcp_process_frto(sk, flag); if (tcp_ack_is_dubious(sk, flag)) { /* Advance CWND, if state allows this. */ if ((flag & FLAG_DATA_ACKED) && !frto_cwnd && tcp_may_raise_cwnd(sk, flag)) tcp_cong_avoid(sk, ack, prior_in_flight, 0); - tcp_fastretrans_alert(sk, prior_snd_una, prior_packets, flag); + tcp_fastretrans_alert(sk, prior_packets, flag); } else { if ((flag & FLAG_DATA_ACKED) && !frto_cwnd) tcp_cong_avoid(sk, ack, prior_in_flight, 1);