From: Eric Dumazet edumazet@google.com
[ Upstream commit 40570375356c874b1578e05c1dcc3ff7c1322dbe ]
We had various bugs over the years with code breaking the assumption that tp->snd_cwnd is greater than zero.
Lately, syzbot reported the WARN_ON_ONCE(!tp->prior_cwnd) added in commit 8b8a321ff72c ("tcp: fix zero cwnd in tcp_cwnd_reduction") can trigger, and without a repro we would have to spend considerable time finding the bug.
Instead of complaining too late, we want to catch where and when tp->snd_cwnd is set to an illegal value.
Signed-off-by: Eric Dumazet edumazet@google.com Suggested-by: Yuchung Cheng ycheng@google.com Cc: Neal Cardwell ncardwell@google.com Acked-by: Yuchung Cheng ycheng@google.com Link: https://lore.kernel.org/r/20220405233538.947344-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/tcp.h | 19 +++++++++++++++---- include/trace/events/tcp.h | 2 +- net/core/filter.c | 2 +- net/ipv4/tcp.c | 8 ++++---- net/ipv4/tcp_bbr.c | 20 ++++++++++---------- net/ipv4/tcp_bic.c | 14 +++++++------- net/ipv4/tcp_cdg.c | 30 +++++++++++++++--------------- net/ipv4/tcp_cong.c | 18 +++++++++--------- net/ipv4/tcp_cubic.c | 22 +++++++++++----------- net/ipv4/tcp_dctcp.c | 11 ++++++----- net/ipv4/tcp_highspeed.c | 18 +++++++++--------- net/ipv4/tcp_htcp.c | 10 +++++----- net/ipv4/tcp_hybla.c | 18 +++++++++--------- net/ipv4/tcp_illinois.c | 12 +++++++----- net/ipv4/tcp_input.c | 36 ++++++++++++++++++------------------ net/ipv4/tcp_ipv4.c | 2 +- net/ipv4/tcp_lp.c | 6 +++--- net/ipv4/tcp_metrics.c | 12 ++++++------ net/ipv4/tcp_nv.c | 24 ++++++++++++------------ net/ipv4/tcp_output.c | 30 +++++++++++++++--------------- net/ipv4/tcp_rate.c | 2 +- net/ipv4/tcp_scalable.c | 4 ++-- net/ipv4/tcp_vegas.c | 21 +++++++++++---------- net/ipv4/tcp_veno.c | 24 ++++++++++++------------ net/ipv4/tcp_westwood.c | 3 ++- net/ipv4/tcp_yeah.c | 30 +++++++++++++++--------------- net/ipv6/tcp_ipv6.c | 2 +- 27 files changed, 208 insertions(+), 192 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h index cc1295037533..2d9a78b3beaa 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1215,9 +1215,20 @@ static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
#define TCP_INFINITE_SSTHRESH 0x7fffffff
+static inline u32 tcp_snd_cwnd(const struct tcp_sock *tp) +{ + return tp->snd_cwnd; +} + +static inline void tcp_snd_cwnd_set(struct tcp_sock *tp, u32 val) +{ + WARN_ON_ONCE((int)val <= 0); + tp->snd_cwnd = val; +} + static inline bool tcp_in_slow_start(const struct tcp_sock *tp) { - return tp->snd_cwnd < tp->snd_ssthresh; + return tcp_snd_cwnd(tp) < tp->snd_ssthresh; }
static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) @@ -1243,8 +1254,8 @@ static inline __u32 tcp_current_ssthresh(const struct sock *sk) return tp->snd_ssthresh; else return max(tp->snd_ssthresh, - ((tp->snd_cwnd >> 1) + - (tp->snd_cwnd >> 2))); + ((tcp_snd_cwnd(tp) >> 1) + + (tcp_snd_cwnd(tp) >> 2))); }
/* Use define here intentionally to get WARN_ON location shown at the caller */ @@ -1286,7 +1297,7 @@ static inline bool tcp_is_cwnd_limited(const struct sock *sk)
/* If in slow start, ensure cwnd grows to twice what was ACKed. */ if (tcp_in_slow_start(tp)) - return tp->snd_cwnd < 2 * tp->max_packets_out; + return tcp_snd_cwnd(tp) < 2 * tp->max_packets_out;
return tp->is_cwnd_limited; } diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h index 521059d8dc0a..edcd6369de10 100644 --- a/include/trace/events/tcp.h +++ b/include/trace/events/tcp.h @@ -279,7 +279,7 @@ TRACE_EVENT(tcp_probe, __entry->data_len = skb->len - __tcp_hdrlen(th); __entry->snd_nxt = tp->snd_nxt; __entry->snd_una = tp->snd_una; - __entry->snd_cwnd = tp->snd_cwnd; + __entry->snd_cwnd = tcp_snd_cwnd(tp); __entry->snd_wnd = tp->snd_wnd; __entry->rcv_wnd = tp->rcv_wnd; __entry->ssthresh = tcp_current_ssthresh(sk); diff --git a/net/core/filter.c b/net/core/filter.c index 966796b345e7..8847316ee20e 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -5173,7 +5173,7 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname, if (val <= 0 || tp->data_segs_out > tp->syn_data) ret = -EINVAL; else - tp->snd_cwnd = val; + tcp_snd_cwnd_set(tp, val); break; case TCP_BPF_SNDCWND_CLAMP: if (val <= 0) { diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index cf18fbcbf123..e31cf137c614 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -429,7 +429,7 @@ void tcp_init_sock(struct sock *sk) * algorithms that we must have the following bandaid to talk * efficiently to them. -DaveM */ - tp->snd_cwnd = TCP_INIT_CWND; + tcp_snd_cwnd_set(tp, TCP_INIT_CWND);
/* There's a bubble in the pipe until at least the first ACK. */ tp->app_limited = ~0U; @@ -3033,7 +3033,7 @@ int tcp_disconnect(struct sock *sk, int flags) icsk->icsk_rto_min = TCP_RTO_MIN; icsk->icsk_delack_max = TCP_DELACK_MAX; tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; - tp->snd_cwnd = TCP_INIT_CWND; + tcp_snd_cwnd_set(tp, TCP_INIT_CWND); tp->snd_cwnd_cnt = 0; tp->window_clamp = 0; tp->delivered = 0; @@ -3744,7 +3744,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info) info->tcpi_max_pacing_rate = rate64;
info->tcpi_reordering = tp->reordering; - info->tcpi_snd_cwnd = tp->snd_cwnd; + info->tcpi_snd_cwnd = tcp_snd_cwnd(tp);
if (info->tcpi_state == TCP_LISTEN) { /* listeners aliased fields : @@ -3915,7 +3915,7 @@ struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk, rate64 = tcp_compute_delivery_rate(tp); nla_put_u64_64bit(stats, TCP_NLA_DELIVERY_RATE, rate64, TCP_NLA_PAD);
- nla_put_u32(stats, TCP_NLA_SND_CWND, tp->snd_cwnd); + nla_put_u32(stats, TCP_NLA_SND_CWND, tcp_snd_cwnd(tp)); nla_put_u32(stats, TCP_NLA_REORDERING, tp->reordering); nla_put_u32(stats, TCP_NLA_MIN_RTT, tcp_min_rtt(tp));
diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c index 02e8626ccb27..c7d30a3bbd81 100644 --- a/net/ipv4/tcp_bbr.c +++ b/net/ipv4/tcp_bbr.c @@ -276,7 +276,7 @@ static void bbr_init_pacing_rate_from_rtt(struct sock *sk) } else { /* no RTT sample yet */ rtt_us = USEC_PER_MSEC; /* use nominal default RTT */ } - bw = (u64)tp->snd_cwnd * BW_UNIT; + bw = (u64)tcp_snd_cwnd(tp) * BW_UNIT; do_div(bw, rtt_us); sk->sk_pacing_rate = bbr_bw_to_pacing_rate(sk, bw, bbr_high_gain); } @@ -323,9 +323,9 @@ static void bbr_save_cwnd(struct sock *sk) struct bbr *bbr = inet_csk_ca(sk);
if (bbr->prev_ca_state < TCP_CA_Recovery && bbr->mode != BBR_PROBE_RTT) - bbr->prior_cwnd = tp->snd_cwnd; /* this cwnd is good enough */ + bbr->prior_cwnd = tcp_snd_cwnd(tp); /* this cwnd is good enough */ else /* loss recovery or BBR_PROBE_RTT have temporarily cut cwnd */ - bbr->prior_cwnd = max(bbr->prior_cwnd, tp->snd_cwnd); + bbr->prior_cwnd = max(bbr->prior_cwnd, tcp_snd_cwnd(tp)); }
static void bbr_cwnd_event(struct sock *sk, enum tcp_ca_event event) @@ -482,7 +482,7 @@ static bool bbr_set_cwnd_to_recover_or_restore( struct tcp_sock *tp = tcp_sk(sk); struct bbr *bbr = inet_csk_ca(sk); u8 prev_state = bbr->prev_ca_state, state = inet_csk(sk)->icsk_ca_state; - u32 cwnd = tp->snd_cwnd; + u32 cwnd = tcp_snd_cwnd(tp);
/* An ACK for P pkts should release at most 2*P packets. We do this * in two steps. First, here we deduct the number of lost packets. @@ -520,7 +520,7 @@ static void bbr_set_cwnd(struct sock *sk, const struct rate_sample *rs, { struct tcp_sock *tp = tcp_sk(sk); struct bbr *bbr = inet_csk_ca(sk); - u32 cwnd = tp->snd_cwnd, target_cwnd = 0; + u32 cwnd = tcp_snd_cwnd(tp), target_cwnd = 0;
if (!acked) goto done; /* no packet fully ACKed; just apply caps */ @@ -544,9 +544,9 @@ static void bbr_set_cwnd(struct sock *sk, const struct rate_sample *rs, cwnd = max(cwnd, bbr_cwnd_min_target);
done: - tp->snd_cwnd = min(cwnd, tp->snd_cwnd_clamp); /* apply global cap */ + tcp_snd_cwnd_set(tp, min(cwnd, tp->snd_cwnd_clamp)); /* apply global cap */ if (bbr->mode == BBR_PROBE_RTT) /* drain queue, refresh min_rtt */ - tp->snd_cwnd = min(tp->snd_cwnd, bbr_cwnd_min_target); + tcp_snd_cwnd_set(tp, min(tcp_snd_cwnd(tp), bbr_cwnd_min_target)); }
/* End cycle phase if it's time and/or we hit the phase's in-flight target. */ @@ -856,7 +856,7 @@ static void bbr_update_ack_aggregation(struct sock *sk, bbr->ack_epoch_acked = min_t(u32, 0xFFFFF, bbr->ack_epoch_acked + rs->acked_sacked); extra_acked = bbr->ack_epoch_acked - expected_acked; - extra_acked = min(extra_acked, tp->snd_cwnd); + extra_acked = min(extra_acked, tcp_snd_cwnd(tp)); if (extra_acked > bbr->extra_acked[bbr->extra_acked_win_idx]) bbr->extra_acked[bbr->extra_acked_win_idx] = extra_acked; } @@ -914,7 +914,7 @@ static void bbr_check_probe_rtt_done(struct sock *sk) return;
bbr->min_rtt_stamp = tcp_jiffies32; /* wait a while until PROBE_RTT */ - tp->snd_cwnd = max(tp->snd_cwnd, bbr->prior_cwnd); + tcp_snd_cwnd_set(tp, max(tcp_snd_cwnd(tp), bbr->prior_cwnd)); bbr_reset_mode(sk); }
@@ -1093,7 +1093,7 @@ static u32 bbr_undo_cwnd(struct sock *sk) bbr->full_bw = 0; /* spurious slow-down; reset full pipe detection */ bbr->full_bw_cnt = 0; bbr_reset_lt_bw_sampling(sk); - return tcp_sk(sk)->snd_cwnd; + return tcp_snd_cwnd(tcp_sk(sk)); }
/* Entering loss recovery, so save cwnd for when we exit or undo recovery. */ diff --git a/net/ipv4/tcp_bic.c b/net/ipv4/tcp_bic.c index f5f588b1f6e9..58358bf92e1b 100644 --- a/net/ipv4/tcp_bic.c +++ b/net/ipv4/tcp_bic.c @@ -150,7 +150,7 @@ static void bictcp_cong_avoid(struct sock *sk, u32 ack, u32 acked) if (!acked) return; } - bictcp_update(ca, tp->snd_cwnd); + bictcp_update(ca, tcp_snd_cwnd(tp)); tcp_cong_avoid_ai(tp, ca->cnt, acked); }
@@ -166,16 +166,16 @@ static u32 bictcp_recalc_ssthresh(struct sock *sk) ca->epoch_start = 0; /* end of epoch */
/* Wmax and fast convergence */ - if (tp->snd_cwnd < ca->last_max_cwnd && fast_convergence) - ca->last_max_cwnd = (tp->snd_cwnd * (BICTCP_BETA_SCALE + beta)) + if (tcp_snd_cwnd(tp) < ca->last_max_cwnd && fast_convergence) + ca->last_max_cwnd = (tcp_snd_cwnd(tp) * (BICTCP_BETA_SCALE + beta)) / (2 * BICTCP_BETA_SCALE); else - ca->last_max_cwnd = tp->snd_cwnd; + ca->last_max_cwnd = tcp_snd_cwnd(tp);
- if (tp->snd_cwnd <= low_window) - return max(tp->snd_cwnd >> 1U, 2U); + if (tcp_snd_cwnd(tp) <= low_window) + return max(tcp_snd_cwnd(tp) >> 1U, 2U); else - return max((tp->snd_cwnd * beta) / BICTCP_BETA_SCALE, 2U); + return max((tcp_snd_cwnd(tp) * beta) / BICTCP_BETA_SCALE, 2U); }
static void bictcp_state(struct sock *sk, u8 new_state) diff --git a/net/ipv4/tcp_cdg.c b/net/ipv4/tcp_cdg.c index 709d23801823..ddc7ba0554bd 100644 --- a/net/ipv4/tcp_cdg.c +++ b/net/ipv4/tcp_cdg.c @@ -161,8 +161,8 @@ static void tcp_cdg_hystart_update(struct sock *sk) LINUX_MIB_TCPHYSTARTTRAINDETECT); NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPHYSTARTTRAINCWND, - tp->snd_cwnd); - tp->snd_ssthresh = tp->snd_cwnd; + tcp_snd_cwnd(tp)); + tp->snd_ssthresh = tcp_snd_cwnd(tp); return; } } @@ -180,8 +180,8 @@ static void tcp_cdg_hystart_update(struct sock *sk) LINUX_MIB_TCPHYSTARTDELAYDETECT); NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPHYSTARTDELAYCWND, - tp->snd_cwnd); - tp->snd_ssthresh = tp->snd_cwnd; + tcp_snd_cwnd(tp)); + tp->snd_ssthresh = tcp_snd_cwnd(tp); } } } @@ -252,7 +252,7 @@ static bool tcp_cdg_backoff(struct sock *sk, u32 grad) return false; }
- ca->shadow_wnd = max(ca->shadow_wnd, tp->snd_cwnd); + ca->shadow_wnd = max(ca->shadow_wnd, tcp_snd_cwnd(tp)); ca->state = CDG_BACKOFF; tcp_enter_cwr(sk); return true; @@ -285,14 +285,14 @@ static void tcp_cdg_cong_avoid(struct sock *sk, u32 ack, u32 acked) }
if (!tcp_is_cwnd_limited(sk)) { - ca->shadow_wnd = min(ca->shadow_wnd, tp->snd_cwnd); + ca->shadow_wnd = min(ca->shadow_wnd, tcp_snd_cwnd(tp)); return; }
- prior_snd_cwnd = tp->snd_cwnd; + prior_snd_cwnd = tcp_snd_cwnd(tp); tcp_reno_cong_avoid(sk, ack, acked);
- incr = tp->snd_cwnd - prior_snd_cwnd; + incr = tcp_snd_cwnd(tp) - prior_snd_cwnd; ca->shadow_wnd = max(ca->shadow_wnd, ca->shadow_wnd + incr); }
@@ -331,15 +331,15 @@ static u32 tcp_cdg_ssthresh(struct sock *sk) struct tcp_sock *tp = tcp_sk(sk);
if (ca->state == CDG_BACKOFF) - return max(2U, (tp->snd_cwnd * min(1024U, backoff_beta)) >> 10); + return max(2U, (tcp_snd_cwnd(tp) * min(1024U, backoff_beta)) >> 10);
if (ca->state == CDG_NONFULL && use_tolerance) - return tp->snd_cwnd; + return tcp_snd_cwnd(tp);
- ca->shadow_wnd = min(ca->shadow_wnd >> 1, tp->snd_cwnd); + ca->shadow_wnd = min(ca->shadow_wnd >> 1, tcp_snd_cwnd(tp)); if (use_shadow) - return max3(2U, ca->shadow_wnd, tp->snd_cwnd >> 1); - return max(2U, tp->snd_cwnd >> 1); + return max3(2U, ca->shadow_wnd, tcp_snd_cwnd(tp) >> 1); + return max(2U, tcp_snd_cwnd(tp) >> 1); }
static void tcp_cdg_cwnd_event(struct sock *sk, const enum tcp_ca_event ev) @@ -357,7 +357,7 @@ static void tcp_cdg_cwnd_event(struct sock *sk, const enum tcp_ca_event ev)
ca->gradients = gradients; ca->rtt_seq = tp->snd_nxt; - ca->shadow_wnd = tp->snd_cwnd; + ca->shadow_wnd = tcp_snd_cwnd(tp); break; case CA_EVENT_COMPLETE_CWR: ca->state = CDG_UNKNOWN; @@ -380,7 +380,7 @@ static void tcp_cdg_init(struct sock *sk) ca->gradients = kcalloc(window, sizeof(ca->gradients[0]), GFP_NOWAIT | __GFP_NOWARN); ca->rtt_seq = tp->snd_nxt; - ca->shadow_wnd = tp->snd_cwnd; + ca->shadow_wnd = tcp_snd_cwnd(tp); }
static void tcp_cdg_release(struct sock *sk) diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c index dc95572163df..d854bcfb9906 100644 --- a/net/ipv4/tcp_cong.c +++ b/net/ipv4/tcp_cong.c @@ -393,10 +393,10 @@ int tcp_set_congestion_control(struct sock *sk, const char *name, bool load, */ u32 tcp_slow_start(struct tcp_sock *tp, u32 acked) { - u32 cwnd = min(tp->snd_cwnd + acked, tp->snd_ssthresh); + u32 cwnd = min(tcp_snd_cwnd(tp) + acked, tp->snd_ssthresh);
- acked -= cwnd - tp->snd_cwnd; - tp->snd_cwnd = min(cwnd, tp->snd_cwnd_clamp); + acked -= cwnd - tcp_snd_cwnd(tp); + tcp_snd_cwnd_set(tp, min(cwnd, tp->snd_cwnd_clamp));
return acked; } @@ -410,7 +410,7 @@ void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked) /* If credits accumulated at a higher w, apply them gently now. */ if (tp->snd_cwnd_cnt >= w) { tp->snd_cwnd_cnt = 0; - tp->snd_cwnd++; + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + 1); }
tp->snd_cwnd_cnt += acked; @@ -418,9 +418,9 @@ void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked) u32 delta = tp->snd_cwnd_cnt / w;
tp->snd_cwnd_cnt -= delta * w; - tp->snd_cwnd += delta; + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + delta); } - tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_cwnd_clamp); + tcp_snd_cwnd_set(tp, min(tcp_snd_cwnd(tp), tp->snd_cwnd_clamp)); } EXPORT_SYMBOL_GPL(tcp_cong_avoid_ai);
@@ -445,7 +445,7 @@ void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked) return; } /* In dangerous area, increase slowly. */ - tcp_cong_avoid_ai(tp, tp->snd_cwnd, acked); + tcp_cong_avoid_ai(tp, tcp_snd_cwnd(tp), acked); } EXPORT_SYMBOL_GPL(tcp_reno_cong_avoid);
@@ -454,7 +454,7 @@ u32 tcp_reno_ssthresh(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk);
- return max(tp->snd_cwnd >> 1U, 2U); + return max(tcp_snd_cwnd(tp) >> 1U, 2U); } EXPORT_SYMBOL_GPL(tcp_reno_ssthresh);
@@ -462,7 +462,7 @@ u32 tcp_reno_undo_cwnd(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk);
- return max(tp->snd_cwnd, tp->prior_cwnd); + return max(tcp_snd_cwnd(tp), tp->prior_cwnd); } EXPORT_SYMBOL_GPL(tcp_reno_undo_cwnd);
diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c index 24d562dd6225..b0918839bee7 100644 --- a/net/ipv4/tcp_cubic.c +++ b/net/ipv4/tcp_cubic.c @@ -334,7 +334,7 @@ static void cubictcp_cong_avoid(struct sock *sk, u32 ack, u32 acked) if (!acked) return; } - bictcp_update(ca, tp->snd_cwnd, acked); + bictcp_update(ca, tcp_snd_cwnd(tp), acked); tcp_cong_avoid_ai(tp, ca->cnt, acked); }
@@ -346,13 +346,13 @@ static u32 cubictcp_recalc_ssthresh(struct sock *sk) ca->epoch_start = 0; /* end of epoch */
/* Wmax and fast convergence */ - if (tp->snd_cwnd < ca->last_max_cwnd && fast_convergence) - ca->last_max_cwnd = (tp->snd_cwnd * (BICTCP_BETA_SCALE + beta)) + if (tcp_snd_cwnd(tp) < ca->last_max_cwnd && fast_convergence) + ca->last_max_cwnd = (tcp_snd_cwnd(tp) * (BICTCP_BETA_SCALE + beta)) / (2 * BICTCP_BETA_SCALE); else - ca->last_max_cwnd = tp->snd_cwnd; + ca->last_max_cwnd = tcp_snd_cwnd(tp);
- return max((tp->snd_cwnd * beta) / BICTCP_BETA_SCALE, 2U); + return max((tcp_snd_cwnd(tp) * beta) / BICTCP_BETA_SCALE, 2U); }
static void cubictcp_state(struct sock *sk, u8 new_state) @@ -413,13 +413,13 @@ static void hystart_update(struct sock *sk, u32 delay) ca->found = 1; pr_debug("hystart_ack_train (%u > %u) delay_min %u (+ ack_delay %u) cwnd %u\n", now - ca->round_start, threshold, - ca->delay_min, hystart_ack_delay(sk), tp->snd_cwnd); + ca->delay_min, hystart_ack_delay(sk), tcp_snd_cwnd(tp)); NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPHYSTARTTRAINDETECT); NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPHYSTARTTRAINCWND, - tp->snd_cwnd); - tp->snd_ssthresh = tp->snd_cwnd; + tcp_snd_cwnd(tp)); + tp->snd_ssthresh = tcp_snd_cwnd(tp); } } } @@ -438,8 +438,8 @@ static void hystart_update(struct sock *sk, u32 delay) LINUX_MIB_TCPHYSTARTDELAYDETECT); NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPHYSTARTDELAYCWND, - tp->snd_cwnd); - tp->snd_ssthresh = tp->snd_cwnd; + tcp_snd_cwnd(tp)); + tp->snd_ssthresh = tcp_snd_cwnd(tp); } } } @@ -469,7 +469,7 @@ static void cubictcp_acked(struct sock *sk, const struct ack_sample *sample)
/* hystart triggers when cwnd is larger than some threshold */ if (!ca->found && tcp_in_slow_start(tp) && hystart && - tp->snd_cwnd >= hystart_low_window) + tcp_snd_cwnd(tp) >= hystart_low_window) hystart_update(sk, delay); }
diff --git a/net/ipv4/tcp_dctcp.c b/net/ipv4/tcp_dctcp.c index 1943a6630341..ab034a4e9324 100644 --- a/net/ipv4/tcp_dctcp.c +++ b/net/ipv4/tcp_dctcp.c @@ -106,8 +106,8 @@ static u32 dctcp_ssthresh(struct sock *sk) struct dctcp *ca = inet_csk_ca(sk); struct tcp_sock *tp = tcp_sk(sk);
- ca->loss_cwnd = tp->snd_cwnd; - return max(tp->snd_cwnd - ((tp->snd_cwnd * ca->dctcp_alpha) >> 11U), 2U); + ca->loss_cwnd = tcp_snd_cwnd(tp); + return max(tcp_snd_cwnd(tp) - ((tcp_snd_cwnd(tp) * ca->dctcp_alpha) >> 11U), 2U); }
static void dctcp_update_alpha(struct sock *sk, u32 flags) @@ -148,8 +148,8 @@ static void dctcp_react_to_loss(struct sock *sk) struct dctcp *ca = inet_csk_ca(sk); struct tcp_sock *tp = tcp_sk(sk);
- ca->loss_cwnd = tp->snd_cwnd; - tp->snd_ssthresh = max(tp->snd_cwnd >> 1U, 2U); + ca->loss_cwnd = tcp_snd_cwnd(tp); + tp->snd_ssthresh = max(tcp_snd_cwnd(tp) >> 1U, 2U); }
static void dctcp_state(struct sock *sk, u8 new_state) @@ -211,8 +211,9 @@ static size_t dctcp_get_info(struct sock *sk, u32 ext, int *attr, static u32 dctcp_cwnd_undo(struct sock *sk) { const struct dctcp *ca = inet_csk_ca(sk); + struct tcp_sock *tp = tcp_sk(sk);
- return max(tcp_sk(sk)->snd_cwnd, ca->loss_cwnd); + return max(tcp_snd_cwnd(tp), ca->loss_cwnd); }
static struct tcp_congestion_ops dctcp __read_mostly = { diff --git a/net/ipv4/tcp_highspeed.c b/net/ipv4/tcp_highspeed.c index 349069d6cd0a..c6de5ce79ad3 100644 --- a/net/ipv4/tcp_highspeed.c +++ b/net/ipv4/tcp_highspeed.c @@ -127,22 +127,22 @@ static void hstcp_cong_avoid(struct sock *sk, u32 ack, u32 acked) * snd_cwnd <= * hstcp_aimd_vals[ca->ai].cwnd */ - if (tp->snd_cwnd > hstcp_aimd_vals[ca->ai].cwnd) { - while (tp->snd_cwnd > hstcp_aimd_vals[ca->ai].cwnd && + if (tcp_snd_cwnd(tp) > hstcp_aimd_vals[ca->ai].cwnd) { + while (tcp_snd_cwnd(tp) > hstcp_aimd_vals[ca->ai].cwnd && ca->ai < HSTCP_AIMD_MAX - 1) ca->ai++; - } else if (ca->ai && tp->snd_cwnd <= hstcp_aimd_vals[ca->ai-1].cwnd) { - while (ca->ai && tp->snd_cwnd <= hstcp_aimd_vals[ca->ai-1].cwnd) + } else if (ca->ai && tcp_snd_cwnd(tp) <= hstcp_aimd_vals[ca->ai-1].cwnd) { + while (ca->ai && tcp_snd_cwnd(tp) <= hstcp_aimd_vals[ca->ai-1].cwnd) ca->ai--; }
/* Do additive increase */ - if (tp->snd_cwnd < tp->snd_cwnd_clamp) { + if (tcp_snd_cwnd(tp) < tp->snd_cwnd_clamp) { /* cwnd = cwnd + a(w) / cwnd */ tp->snd_cwnd_cnt += ca->ai + 1; - if (tp->snd_cwnd_cnt >= tp->snd_cwnd) { - tp->snd_cwnd_cnt -= tp->snd_cwnd; - tp->snd_cwnd++; + if (tp->snd_cwnd_cnt >= tcp_snd_cwnd(tp)) { + tp->snd_cwnd_cnt -= tcp_snd_cwnd(tp); + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + 1); } } } @@ -154,7 +154,7 @@ static u32 hstcp_ssthresh(struct sock *sk) struct hstcp *ca = inet_csk_ca(sk);
/* Do multiplicative decrease */ - return max(tp->snd_cwnd - ((tp->snd_cwnd * hstcp_aimd_vals[ca->ai].md) >> 8), 2U); + return max(tcp_snd_cwnd(tp) - ((tcp_snd_cwnd(tp) * hstcp_aimd_vals[ca->ai].md) >> 8), 2U); }
static struct tcp_congestion_ops tcp_highspeed __read_mostly = { diff --git a/net/ipv4/tcp_htcp.c b/net/ipv4/tcp_htcp.c index 55adcfcf96fe..52b1f2665dfa 100644 --- a/net/ipv4/tcp_htcp.c +++ b/net/ipv4/tcp_htcp.c @@ -124,7 +124,7 @@ static void measure_achieved_throughput(struct sock *sk,
ca->packetcount += sample->pkts_acked;
- if (ca->packetcount >= tp->snd_cwnd - (ca->alpha >> 7 ? : 1) && + if (ca->packetcount >= tcp_snd_cwnd(tp) - (ca->alpha >> 7 ? : 1) && now - ca->lasttime >= ca->minRTT && ca->minRTT > 0) { __u32 cur_Bi = ca->packetcount * HZ / (now - ca->lasttime); @@ -225,7 +225,7 @@ static u32 htcp_recalc_ssthresh(struct sock *sk) const struct htcp *ca = inet_csk_ca(sk);
htcp_param_update(sk); - return max((tp->snd_cwnd * ca->beta) >> 7, 2U); + return max((tcp_snd_cwnd(tp) * ca->beta) >> 7, 2U); }
static void htcp_cong_avoid(struct sock *sk, u32 ack, u32 acked) @@ -242,9 +242,9 @@ static void htcp_cong_avoid(struct sock *sk, u32 ack, u32 acked) /* In dangerous area, increase slowly. * In theory this is tp->snd_cwnd += alpha / tp->snd_cwnd */ - if ((tp->snd_cwnd_cnt * ca->alpha)>>7 >= tp->snd_cwnd) { - if (tp->snd_cwnd < tp->snd_cwnd_clamp) - tp->snd_cwnd++; + if ((tp->snd_cwnd_cnt * ca->alpha)>>7 >= tcp_snd_cwnd(tp)) { + if (tcp_snd_cwnd(tp) < tp->snd_cwnd_clamp) + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + 1); tp->snd_cwnd_cnt = 0; htcp_alpha_update(ca); } else diff --git a/net/ipv4/tcp_hybla.c b/net/ipv4/tcp_hybla.c index be39327e04e6..abd7d91807e5 100644 --- a/net/ipv4/tcp_hybla.c +++ b/net/ipv4/tcp_hybla.c @@ -54,7 +54,7 @@ static void hybla_init(struct sock *sk) ca->rho2_7ls = 0; ca->snd_cwnd_cents = 0; ca->hybla_en = true; - tp->snd_cwnd = 2; + tcp_snd_cwnd_set(tp, 2); tp->snd_cwnd_clamp = 65535;
/* 1st Rho measurement based on initial srtt */ @@ -62,7 +62,7 @@ static void hybla_init(struct sock *sk)
/* set minimum rtt as this is the 1st ever seen */ ca->minrtt_us = tp->srtt_us; - tp->snd_cwnd = ca->rho; + tcp_snd_cwnd_set(tp, ca->rho); }
static void hybla_state(struct sock *sk, u8 ca_state) @@ -137,31 +137,31 @@ static void hybla_cong_avoid(struct sock *sk, u32 ack, u32 acked) * as long as increment is estimated as (rho<<7)/window * it already is <<7 and we can easily count its fractions. */ - increment = ca->rho2_7ls / tp->snd_cwnd; + increment = ca->rho2_7ls / tcp_snd_cwnd(tp); if (increment < 128) tp->snd_cwnd_cnt++; }
odd = increment % 128; - tp->snd_cwnd += increment >> 7; + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + (increment >> 7)); ca->snd_cwnd_cents += odd;
/* check when fractions goes >=128 and increase cwnd by 1. */ while (ca->snd_cwnd_cents >= 128) { - tp->snd_cwnd++; + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + 1); ca->snd_cwnd_cents -= 128; tp->snd_cwnd_cnt = 0; } /* check when cwnd has not been incremented for a while */ - if (increment == 0 && odd == 0 && tp->snd_cwnd_cnt >= tp->snd_cwnd) { - tp->snd_cwnd++; + if (increment == 0 && odd == 0 && tp->snd_cwnd_cnt >= tcp_snd_cwnd(tp)) { + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + 1); tp->snd_cwnd_cnt = 0; } /* clamp down slowstart cwnd to ssthresh value. */ if (is_slowstart) - tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh); + tcp_snd_cwnd_set(tp, min(tcp_snd_cwnd(tp), tp->snd_ssthresh));
- tp->snd_cwnd = min_t(u32, tp->snd_cwnd, tp->snd_cwnd_clamp); + tcp_snd_cwnd_set(tp, min(tcp_snd_cwnd(tp), tp->snd_cwnd_clamp)); }
static struct tcp_congestion_ops tcp_hybla __read_mostly = { diff --git a/net/ipv4/tcp_illinois.c b/net/ipv4/tcp_illinois.c index 00e54873213e..c0c81a2c77fa 100644 --- a/net/ipv4/tcp_illinois.c +++ b/net/ipv4/tcp_illinois.c @@ -224,7 +224,7 @@ static void update_params(struct sock *sk) struct tcp_sock *tp = tcp_sk(sk); struct illinois *ca = inet_csk_ca(sk);
- if (tp->snd_cwnd < win_thresh) { + if (tcp_snd_cwnd(tp) < win_thresh) { ca->alpha = ALPHA_BASE; ca->beta = BETA_BASE; } else if (ca->cnt_rtt > 0) { @@ -284,9 +284,9 @@ static void tcp_illinois_cong_avoid(struct sock *sk, u32 ack, u32 acked) * tp->snd_cwnd += alpha/tp->snd_cwnd */ delta = (tp->snd_cwnd_cnt * ca->alpha) >> ALPHA_SHIFT; - if (delta >= tp->snd_cwnd) { - tp->snd_cwnd = min(tp->snd_cwnd + delta / tp->snd_cwnd, - (u32)tp->snd_cwnd_clamp); + if (delta >= tcp_snd_cwnd(tp)) { + tcp_snd_cwnd_set(tp, min(tcp_snd_cwnd(tp) + delta / tcp_snd_cwnd(tp), + (u32)tp->snd_cwnd_clamp)); tp->snd_cwnd_cnt = 0; } } @@ -296,9 +296,11 @@ static u32 tcp_illinois_ssthresh(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); struct illinois *ca = inet_csk_ca(sk); + u32 decr;
/* Multiplicative decrease */ - return max(tp->snd_cwnd - ((tp->snd_cwnd * ca->beta) >> BETA_SHIFT), 2U); + decr = (tcp_snd_cwnd(tp) * ca->beta) >> BETA_SHIFT; + return max(tcp_snd_cwnd(tp) - decr, 2U); }
/* Extract info for Tcp socket info provided via netlink. */ diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 1f3ce7aea716..59593fba9e35 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -414,7 +414,7 @@ static void tcp_sndbuf_expand(struct sock *sk) per_mss = roundup_pow_of_two(per_mss) + SKB_DATA_ALIGN(sizeof(struct sk_buff));
- nr_segs = max_t(u32, TCP_INIT_CWND, tp->snd_cwnd); + nr_segs = max_t(u32, TCP_INIT_CWND, tcp_snd_cwnd(tp)); nr_segs = max_t(u32, nr_segs, tp->reordering + 1);
/* Fast Recovery (RFC 5681 3.2) : @@ -909,12 +909,12 @@ static void tcp_update_pacing_rate(struct sock *sk) * If snd_cwnd >= (tp->snd_ssthresh / 2), we are approaching * end of slow start and should slow down. */ - if (tp->snd_cwnd < tp->snd_ssthresh / 2) + if (tcp_snd_cwnd(tp) < tp->snd_ssthresh / 2) rate *= sock_net(sk)->ipv4.sysctl_tcp_pacing_ss_ratio; else rate *= sock_net(sk)->ipv4.sysctl_tcp_pacing_ca_ratio;
- rate *= max(tp->snd_cwnd, tp->packets_out); + rate *= max(tcp_snd_cwnd(tp), tp->packets_out);
if (likely(tp->srtt_us)) do_div(rate, tp->srtt_us); @@ -2147,12 +2147,12 @@ void tcp_enter_loss(struct sock *sk) !after(tp->high_seq, tp->snd_una) || (icsk->icsk_ca_state == TCP_CA_Loss && !icsk->icsk_retransmits)) { tp->prior_ssthresh = tcp_current_ssthresh(sk); - tp->prior_cwnd = tp->snd_cwnd; + tp->prior_cwnd = tcp_snd_cwnd(tp); tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk); tcp_ca_event(sk, CA_EVENT_LOSS); tcp_init_undo(tp); } - tp->snd_cwnd = tcp_packets_in_flight(tp) + 1; + tcp_snd_cwnd_set(tp, tcp_packets_in_flight(tp) + 1); tp->snd_cwnd_cnt = 0; tp->snd_cwnd_stamp = tcp_jiffies32;
@@ -2458,7 +2458,7 @@ static void DBGUNDO(struct sock *sk, const char *msg) pr_debug("Undo %s %pI4/%u c%u l%u ss%u/%u p%u\n", msg, &inet->inet_daddr, ntohs(inet->inet_dport), - tp->snd_cwnd, tcp_left_out(tp), + tcp_snd_cwnd(tp), tcp_left_out(tp), tp->snd_ssthresh, tp->prior_ssthresh, tp->packets_out); } @@ -2467,7 +2467,7 @@ static void DBGUNDO(struct sock *sk, const char *msg) pr_debug("Undo %s %pI6/%u c%u l%u ss%u/%u p%u\n", msg, &sk->sk_v6_daddr, ntohs(inet->inet_dport), - tp->snd_cwnd, tcp_left_out(tp), + tcp_snd_cwnd(tp), tcp_left_out(tp), tp->snd_ssthresh, tp->prior_ssthresh, tp->packets_out); } @@ -2492,7 +2492,7 @@ static void tcp_undo_cwnd_reduction(struct sock *sk, bool unmark_loss) if (tp->prior_ssthresh) { const struct inet_connection_sock *icsk = inet_csk(sk);
- tp->snd_cwnd = icsk->icsk_ca_ops->undo_cwnd(sk); + tcp_snd_cwnd_set(tp, icsk->icsk_ca_ops->undo_cwnd(sk));
if (tp->prior_ssthresh > tp->snd_ssthresh) { tp->snd_ssthresh = tp->prior_ssthresh; @@ -2599,7 +2599,7 @@ static void tcp_init_cwnd_reduction(struct sock *sk) tp->high_seq = tp->snd_nxt; tp->tlp_high_seq = 0; tp->snd_cwnd_cnt = 0; - tp->prior_cwnd = tp->snd_cwnd; + tp->prior_cwnd = tcp_snd_cwnd(tp); tp->prr_delivered = 0; tp->prr_out = 0; tp->snd_ssthresh = inet_csk(sk)->icsk_ca_ops->ssthresh(sk); @@ -2629,7 +2629,7 @@ void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, int newly_lost, } /* Force a fast retransmit upon entering fast recovery */ sndcnt = max(sndcnt, (tp->prr_out ? 0 : 1)); - tp->snd_cwnd = tcp_packets_in_flight(tp) + sndcnt; + tcp_snd_cwnd_set(tp, tcp_packets_in_flight(tp) + sndcnt); }
static inline void tcp_end_cwnd_reduction(struct sock *sk) @@ -2642,7 +2642,7 @@ static inline void tcp_end_cwnd_reduction(struct sock *sk) /* Reset cwnd to ssthresh in CWR or Recovery (unless it's undone) */ if (tp->snd_ssthresh < TCP_INFINITE_SSTHRESH && (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR || tp->undo_marker)) { - tp->snd_cwnd = tp->snd_ssthresh; + tcp_snd_cwnd_set(tp, tp->snd_ssthresh); tp->snd_cwnd_stamp = tcp_jiffies32; } tcp_ca_event(sk, CA_EVENT_COMPLETE_CWR); @@ -2709,9 +2709,9 @@ static void tcp_mtup_probe_success(struct sock *sk)
/* FIXME: breaks with very large cwnd */ 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; + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) * + tcp_mss_to_mtu(sk, tp->mss_cache) / + icsk->icsk_mtup.probe_size); tp->snd_cwnd_cnt = 0; tp->snd_cwnd_stamp = tcp_jiffies32; tp->snd_ssthresh = tcp_current_ssthresh(sk); @@ -3034,7 +3034,7 @@ static void tcp_fastretrans_alert(struct sock *sk, const u32 prior_snd_una, tp->snd_una == tp->mtu_probe.probe_seq_start) { tcp_mtup_probe_failed(sk); /* Restores the reduction we did in tcp_mtup_probe() */ - tp->snd_cwnd++; + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + 1); tcp_simple_retransmit(sk); return; } @@ -5437,7 +5437,7 @@ static bool tcp_should_expand_sndbuf(struct sock *sk) return false;
/* If we filled the congestion window, do not expand. */ - if (tcp_packets_in_flight(tp) >= tp->snd_cwnd) + if (tcp_packets_in_flight(tp) >= tcp_snd_cwnd(tp)) return false;
return true; @@ -6013,9 +6013,9 @@ void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb) * retransmission has occurred. */ if (tp->total_retrans > 1 && tp->undo_marker) - tp->snd_cwnd = 1; + tcp_snd_cwnd_set(tp, 1); else - tp->snd_cwnd = tcp_init_cwnd(tp, __sk_dst_get(sk)); + tcp_snd_cwnd_set(tp, tcp_init_cwnd(tp, __sk_dst_get(sk))); tp->snd_cwnd_stamp = tcp_jiffies32;
bpf_skops_established(sk, bpf_op, skb); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 457f5b5d5d4a..30a74e4eeab4 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2621,7 +2621,7 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i) jiffies_to_clock_t(icsk->icsk_rto), jiffies_to_clock_t(icsk->icsk_ack.ato), (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk), - tp->snd_cwnd, + tcp_snd_cwnd(tp), state == TCP_LISTEN ? fastopenq->max_qlen : (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)); diff --git a/net/ipv4/tcp_lp.c b/net/ipv4/tcp_lp.c index 82b36ec3f2f8..ae36780977d2 100644 --- a/net/ipv4/tcp_lp.c +++ b/net/ipv4/tcp_lp.c @@ -297,7 +297,7 @@ static void tcp_lp_pkts_acked(struct sock *sk, const struct ack_sample *sample) lp->flag &= ~LP_WITHIN_THR;
pr_debug("TCP-LP: %05o|%5u|%5u|%15u|%15u|%15u\n", lp->flag, - tp->snd_cwnd, lp->remote_hz, lp->owd_min, lp->owd_max, + tcp_snd_cwnd(tp), lp->remote_hz, lp->owd_min, lp->owd_max, lp->sowd >> 3);
if (lp->flag & LP_WITHIN_THR) @@ -313,12 +313,12 @@ static void tcp_lp_pkts_acked(struct sock *sk, const struct ack_sample *sample) /* happened within inference * drop snd_cwnd into 1 */ if (lp->flag & LP_WITHIN_INF) - tp->snd_cwnd = 1U; + tcp_snd_cwnd_set(tp, 1U);
/* happened after inference * cut snd_cwnd into half */ else - tp->snd_cwnd = max(tp->snd_cwnd >> 1U, 1U); + tcp_snd_cwnd_set(tp, max(tcp_snd_cwnd(tp) >> 1U, 1U));
/* record this drop time */ lp->last_drop = now; diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 0588b004ddac..7029b0e98edb 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -388,15 +388,15 @@ void tcp_update_metrics(struct sock *sk) if (!net->ipv4.sysctl_tcp_no_ssthresh_metrics_save && !tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); - if (val && (tp->snd_cwnd >> 1) > val) + if (val && (tcp_snd_cwnd(tp) >> 1) > val) tcp_metric_set(tm, TCP_METRIC_SSTHRESH, - tp->snd_cwnd >> 1); + tcp_snd_cwnd(tp) >> 1); } if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { val = tcp_metric_get(tm, TCP_METRIC_CWND); - if (tp->snd_cwnd > val) + if (tcp_snd_cwnd(tp) > val) tcp_metric_set(tm, TCP_METRIC_CWND, - tp->snd_cwnd); + tcp_snd_cwnd(tp)); } } else if (!tcp_in_slow_start(tp) && icsk->icsk_ca_state == TCP_CA_Open) { @@ -404,10 +404,10 @@ void tcp_update_metrics(struct sock *sk) if (!net->ipv4.sysctl_tcp_no_ssthresh_metrics_save && !tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) tcp_metric_set(tm, TCP_METRIC_SSTHRESH, - max(tp->snd_cwnd >> 1, tp->snd_ssthresh)); + max(tcp_snd_cwnd(tp) >> 1, tp->snd_ssthresh)); if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { val = tcp_metric_get(tm, TCP_METRIC_CWND); - tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1); + tcp_metric_set(tm, TCP_METRIC_CWND, (val + tcp_snd_cwnd(tp)) >> 1); } } else { /* Else slow start did not finish, cwnd is non-sense, diff --git a/net/ipv4/tcp_nv.c b/net/ipv4/tcp_nv.c index ab552356bdba..a60662f4bdf9 100644 --- a/net/ipv4/tcp_nv.c +++ b/net/ipv4/tcp_nv.c @@ -197,10 +197,10 @@ static void tcpnv_cong_avoid(struct sock *sk, u32 ack, u32 acked) }
if (ca->cwnd_growth_factor < 0) { - cnt = tp->snd_cwnd << -ca->cwnd_growth_factor; + cnt = tcp_snd_cwnd(tp) << -ca->cwnd_growth_factor; tcp_cong_avoid_ai(tp, cnt, acked); } else { - cnt = max(4U, tp->snd_cwnd >> ca->cwnd_growth_factor); + cnt = max(4U, tcp_snd_cwnd(tp) >> ca->cwnd_growth_factor); tcp_cong_avoid_ai(tp, cnt, acked); } } @@ -209,7 +209,7 @@ static u32 tcpnv_recalc_ssthresh(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk);
- return max((tp->snd_cwnd * nv_loss_dec_factor) >> 10, 2U); + return max((tcp_snd_cwnd(tp) * nv_loss_dec_factor) >> 10, 2U); }
static void tcpnv_state(struct sock *sk, u8 new_state) @@ -257,7 +257,7 @@ static void tcpnv_acked(struct sock *sk, const struct ack_sample *sample) return;
/* Stop cwnd growth if we were in catch up mode */ - if (ca->nv_catchup && tp->snd_cwnd >= nv_min_cwnd) { + if (ca->nv_catchup && tcp_snd_cwnd(tp) >= nv_min_cwnd) { ca->nv_catchup = 0; ca->nv_allow_cwnd_growth = 0; } @@ -371,7 +371,7 @@ static void tcpnv_acked(struct sock *sk, const struct ack_sample *sample) * if cwnd < max_win, grow cwnd * else leave the same */ - if (tp->snd_cwnd > max_win) { + if (tcp_snd_cwnd(tp) > max_win) { /* there is congestion, check that it is ok * to make a CA decision * 1. We should have at least nv_dec_eval_min_calls @@ -398,20 +398,20 @@ static void tcpnv_acked(struct sock *sk, const struct ack_sample *sample) ca->nv_allow_cwnd_growth = 0; tp->snd_ssthresh = (nv_ssthresh_factor * max_win) >> 3; - if (tp->snd_cwnd - max_win > 2) { + if (tcp_snd_cwnd(tp) - max_win > 2) { /* gap > 2, we do exponential cwnd decrease */ int dec;
- dec = max(2U, ((tp->snd_cwnd - max_win) * + dec = max(2U, ((tcp_snd_cwnd(tp) - max_win) * nv_cong_dec_mult) >> 7); - tp->snd_cwnd -= dec; + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) - dec); } else if (nv_cong_dec_mult > 0) { - tp->snd_cwnd = max_win; + tcp_snd_cwnd_set(tp, max_win); } if (ca->cwnd_growth_factor > 0) ca->cwnd_growth_factor = 0; ca->nv_no_cong_cnt = 0; - } else if (tp->snd_cwnd <= max_win - nv_pad_buffer) { + } else if (tcp_snd_cwnd(tp) <= max_win - nv_pad_buffer) { /* There is no congestion, grow cwnd if allowed*/ if (ca->nv_eval_call_cnt < nv_inc_eval_min_calls) return; @@ -444,8 +444,8 @@ static void tcpnv_acked(struct sock *sk, const struct ack_sample *sample) * (it wasn't before, if it is now is because nv * decreased it). */ - if (tp->snd_cwnd < nv_min_cwnd) - tp->snd_cwnd = nv_min_cwnd; + if (tcp_snd_cwnd(tp) < nv_min_cwnd) + tcp_snd_cwnd_set(tp, nv_min_cwnd); } }
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 1ca2f28c9981..5f91a9536e00 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -143,7 +143,7 @@ void tcp_cwnd_restart(struct sock *sk, s32 delta) { struct tcp_sock *tp = tcp_sk(sk); u32 restart_cwnd = tcp_init_cwnd(tp, __sk_dst_get(sk)); - u32 cwnd = tp->snd_cwnd; + u32 cwnd = tcp_snd_cwnd(tp);
tcp_ca_event(sk, CA_EVENT_CWND_RESTART);
@@ -152,7 +152,7 @@ void tcp_cwnd_restart(struct sock *sk, s32 delta)
while ((delta -= inet_csk(sk)->icsk_rto) > 0 && cwnd > restart_cwnd) cwnd >>= 1; - tp->snd_cwnd = max(cwnd, restart_cwnd); + tcp_snd_cwnd_set(tp, max(cwnd, restart_cwnd)); tp->snd_cwnd_stamp = tcp_jiffies32; tp->snd_cwnd_used = 0; } @@ -1014,7 +1014,7 @@ static void tcp_tsq_write(struct sock *sk) struct tcp_sock *tp = tcp_sk(sk);
if (tp->lost_out > tp->retrans_out && - tp->snd_cwnd > tcp_packets_in_flight(tp)) { + tcp_snd_cwnd(tp) > tcp_packets_in_flight(tp)) { tcp_mstamp_refresh(tp); tcp_xmit_retransmit_queue(sk); } @@ -1861,9 +1861,9 @@ static void tcp_cwnd_application_limited(struct sock *sk) /* Limited by application or receiver window. */ 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) { + if (win_used < tcp_snd_cwnd(tp)) { tp->snd_ssthresh = tcp_current_ssthresh(sk); - tp->snd_cwnd = (tp->snd_cwnd + win_used) >> 1; + tcp_snd_cwnd_set(tp, (tcp_snd_cwnd(tp) + win_used) >> 1); } tp->snd_cwnd_used = 0; } @@ -2044,7 +2044,7 @@ static inline unsigned int tcp_cwnd_test(const struct tcp_sock *tp, return 1;
in_flight = tcp_packets_in_flight(tp); - cwnd = tp->snd_cwnd; + cwnd = tcp_snd_cwnd(tp); if (in_flight >= cwnd) return 0;
@@ -2197,12 +2197,12 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb, in_flight = tcp_packets_in_flight(tp);
BUG_ON(tcp_skb_pcount(skb) <= 1); - BUG_ON(tp->snd_cwnd <= in_flight); + BUG_ON(tcp_snd_cwnd(tp) <= in_flight);
send_win = tcp_wnd_end(tp) - TCP_SKB_CB(skb)->seq;
/* From in_flight test above, we know that cwnd > in_flight. */ - cong_win = (tp->snd_cwnd - in_flight) * tp->mss_cache; + cong_win = (tcp_snd_cwnd(tp) - in_flight) * tp->mss_cache;
limit = min(send_win, cong_win);
@@ -2216,7 +2216,7 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
win_divisor = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_tso_win_divisor); if (win_divisor) { - u32 chunk = min(tp->snd_wnd, tp->snd_cwnd * tp->mss_cache); + u32 chunk = min(tp->snd_wnd, tcp_snd_cwnd(tp) * tp->mss_cache);
/* If at least some fraction of a window is available, * just use it. @@ -2346,7 +2346,7 @@ static int tcp_mtu_probe(struct sock *sk) if (likely(!icsk->icsk_mtup.enabled || icsk->icsk_mtup.probe_size || inet_csk(sk)->icsk_ca_state != TCP_CA_Open || - tp->snd_cwnd < 11 || + tcp_snd_cwnd(tp) < 11 || tp->rx_opt.num_sacks || tp->rx_opt.dsack)) return -1;
@@ -2382,7 +2382,7 @@ static int tcp_mtu_probe(struct sock *sk) return 0;
/* Do we need to wait to drain cwnd? With none in flight, don't stall */ - if (tcp_packets_in_flight(tp) + 2 > tp->snd_cwnd) { + if (tcp_packets_in_flight(tp) + 2 > tcp_snd_cwnd(tp)) { if (!tcp_packets_in_flight(tp)) return -1; else @@ -2451,7 +2451,7 @@ static int tcp_mtu_probe(struct sock *sk) if (!tcp_transmit_skb(sk, nskb, 1, GFP_ATOMIC)) { /* Decrement cwnd here because we are sending * effectively two packets. */ - tp->snd_cwnd--; + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) - 1); tcp_event_new_data_sent(sk, nskb);
icsk->icsk_mtup.probe_size = tcp_mss_to_mtu(sk, nskb->len); @@ -2709,7 +2709,7 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle, else tcp_chrono_stop(sk, TCP_CHRONO_RWND_LIMITED);
- is_cwnd_limited |= (tcp_packets_in_flight(tp) >= tp->snd_cwnd); + is_cwnd_limited |= (tcp_packets_in_flight(tp) >= tcp_snd_cwnd(tp)); if (likely(sent_pkts || is_cwnd_limited)) tcp_cwnd_validate(sk, is_cwnd_limited);
@@ -2819,7 +2819,7 @@ void tcp_send_loss_probe(struct sock *sk) if (unlikely(!skb)) { WARN_ONCE(tp->packets_out, "invalid inflight: %u state %u cwnd %u mss %d\n", - tp->packets_out, sk->sk_state, tp->snd_cwnd, mss); + tp->packets_out, sk->sk_state, tcp_snd_cwnd(tp), mss); inet_csk(sk)->icsk_pending = 0; return; } @@ -3303,7 +3303,7 @@ void tcp_xmit_retransmit_queue(struct sock *sk) if (!hole) tp->retransmit_skb_hint = skb;
- segs = tp->snd_cwnd - tcp_packets_in_flight(tp); + segs = tcp_snd_cwnd(tp) - tcp_packets_in_flight(tp); if (segs <= 0) break; sacked = TCP_SKB_CB(skb)->sacked; diff --git a/net/ipv4/tcp_rate.c b/net/ipv4/tcp_rate.c index 9a8e014d9b5b..a8f6d9d06f2e 100644 --- a/net/ipv4/tcp_rate.c +++ b/net/ipv4/tcp_rate.c @@ -200,7 +200,7 @@ void tcp_rate_check_app_limited(struct sock *sk) /* Nothing in sending host's qdisc queues or NIC tx queue. */ sk_wmem_alloc_get(sk) < SKB_TRUESIZE(1) && /* We are not limited by CWND. */ - tcp_packets_in_flight(tp) < tp->snd_cwnd && + tcp_packets_in_flight(tp) < tcp_snd_cwnd(tp) && /* All lost packets have been retransmitted. */ tp->lost_out <= tp->retrans_out) tp->app_limited = diff --git a/net/ipv4/tcp_scalable.c b/net/ipv4/tcp_scalable.c index 5842081bc8a2..862b96248a92 100644 --- a/net/ipv4/tcp_scalable.c +++ b/net/ipv4/tcp_scalable.c @@ -27,7 +27,7 @@ static void tcp_scalable_cong_avoid(struct sock *sk, u32 ack, u32 acked) if (!acked) return; } - tcp_cong_avoid_ai(tp, min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT), + tcp_cong_avoid_ai(tp, min(tcp_snd_cwnd(tp), TCP_SCALABLE_AI_CNT), acked); }
@@ -35,7 +35,7 @@ static u32 tcp_scalable_ssthresh(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk);
- return max(tp->snd_cwnd - (tp->snd_cwnd>>TCP_SCALABLE_MD_SCALE), 2U); + return max(tcp_snd_cwnd(tp) - (tcp_snd_cwnd(tp)>>TCP_SCALABLE_MD_SCALE), 2U); }
static struct tcp_congestion_ops tcp_scalable __read_mostly = { diff --git a/net/ipv4/tcp_vegas.c b/net/ipv4/tcp_vegas.c index c8003c8aad2c..786848ad37ea 100644 --- a/net/ipv4/tcp_vegas.c +++ b/net/ipv4/tcp_vegas.c @@ -159,7 +159,7 @@ EXPORT_SYMBOL_GPL(tcp_vegas_cwnd_event);
static inline u32 tcp_vegas_ssthresh(struct tcp_sock *tp) { - return min(tp->snd_ssthresh, tp->snd_cwnd); + return min(tp->snd_ssthresh, tcp_snd_cwnd(tp)); }
static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack, u32 acked) @@ -217,14 +217,14 @@ static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack, u32 acked) * This is: * (actual rate in segments) * baseRTT */ - target_cwnd = (u64)tp->snd_cwnd * vegas->baseRTT; + target_cwnd = (u64)tcp_snd_cwnd(tp) * vegas->baseRTT; do_div(target_cwnd, rtt);
/* Calculate the difference between the window we had, * and the window we would like to have. This quantity * is the "Diff" from the Arizona Vegas papers. */ - diff = tp->snd_cwnd * (rtt-vegas->baseRTT) / vegas->baseRTT; + diff = tcp_snd_cwnd(tp) * (rtt-vegas->baseRTT) / vegas->baseRTT;
if (diff > gamma && tcp_in_slow_start(tp)) { /* Going too fast. Time to slow down @@ -238,7 +238,8 @@ static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack, u32 acked) * truncation robs us of full link * utilization. */ - tp->snd_cwnd = min(tp->snd_cwnd, (u32)target_cwnd+1); + tcp_snd_cwnd_set(tp, min(tcp_snd_cwnd(tp), + (u32)target_cwnd + 1)); tp->snd_ssthresh = tcp_vegas_ssthresh(tp);
} else if (tcp_in_slow_start(tp)) { @@ -254,14 +255,14 @@ static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack, u32 acked) /* The old window was too fast, so * we slow down. */ - tp->snd_cwnd--; + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) - 1); tp->snd_ssthresh = tcp_vegas_ssthresh(tp); } else if (diff < alpha) { /* We don't have enough extra packets * in the network, so speed up. */ - tp->snd_cwnd++; + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + 1); } else { /* Sending just as fast as we * should be. @@ -269,10 +270,10 @@ static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack, u32 acked) } }
- if (tp->snd_cwnd < 2) - tp->snd_cwnd = 2; - else if (tp->snd_cwnd > tp->snd_cwnd_clamp) - tp->snd_cwnd = tp->snd_cwnd_clamp; + if (tcp_snd_cwnd(tp) < 2) + tcp_snd_cwnd_set(tp, 2); + else if (tcp_snd_cwnd(tp) > tp->snd_cwnd_clamp) + tcp_snd_cwnd_set(tp, tp->snd_cwnd_clamp);
tp->snd_ssthresh = tcp_current_ssthresh(sk); } diff --git a/net/ipv4/tcp_veno.c b/net/ipv4/tcp_veno.c index cd50a61c9976..366ff6f214b2 100644 --- a/net/ipv4/tcp_veno.c +++ b/net/ipv4/tcp_veno.c @@ -146,11 +146,11 @@ static void tcp_veno_cong_avoid(struct sock *sk, u32 ack, u32 acked)
rtt = veno->minrtt;
- target_cwnd = (u64)tp->snd_cwnd * veno->basertt; + target_cwnd = (u64)tcp_snd_cwnd(tp) * veno->basertt; target_cwnd <<= V_PARAM_SHIFT; do_div(target_cwnd, rtt);
- veno->diff = (tp->snd_cwnd << V_PARAM_SHIFT) - target_cwnd; + veno->diff = (tcp_snd_cwnd(tp) << V_PARAM_SHIFT) - target_cwnd;
if (tcp_in_slow_start(tp)) { /* Slow start. */ @@ -164,15 +164,15 @@ static void tcp_veno_cong_avoid(struct sock *sk, u32 ack, u32 acked) /* In the "non-congestive state", increase cwnd * every rtt. */ - tcp_cong_avoid_ai(tp, tp->snd_cwnd, acked); + tcp_cong_avoid_ai(tp, tcp_snd_cwnd(tp), acked); } else { /* In the "congestive state", increase cwnd * every other rtt. */ - if (tp->snd_cwnd_cnt >= tp->snd_cwnd) { + if (tp->snd_cwnd_cnt >= tcp_snd_cwnd(tp)) { if (veno->inc && - tp->snd_cwnd < tp->snd_cwnd_clamp) { - tp->snd_cwnd++; + tcp_snd_cwnd(tp) < tp->snd_cwnd_clamp) { + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + 1); veno->inc = 0; } else veno->inc = 1; @@ -181,10 +181,10 @@ static void tcp_veno_cong_avoid(struct sock *sk, u32 ack, u32 acked) tp->snd_cwnd_cnt += acked; } done: - if (tp->snd_cwnd < 2) - tp->snd_cwnd = 2; - else if (tp->snd_cwnd > tp->snd_cwnd_clamp) - tp->snd_cwnd = tp->snd_cwnd_clamp; + if (tcp_snd_cwnd(tp) < 2) + tcp_snd_cwnd_set(tp, 2); + else if (tcp_snd_cwnd(tp) > tp->snd_cwnd_clamp) + tcp_snd_cwnd_set(tp, tp->snd_cwnd_clamp); } /* Wipe the slate clean for the next rtt. */ /* veno->cntrtt = 0; */ @@ -199,10 +199,10 @@ static u32 tcp_veno_ssthresh(struct sock *sk)
if (veno->diff < beta) /* in "non-congestive state", cut cwnd by 1/5 */ - return max(tp->snd_cwnd * 4 / 5, 2U); + return max(tcp_snd_cwnd(tp) * 4 / 5, 2U); else /* in "congestive state", cut cwnd by 1/2 */ - return max(tp->snd_cwnd >> 1U, 2U); + return max(tcp_snd_cwnd(tp) >> 1U, 2U); }
static struct tcp_congestion_ops tcp_veno __read_mostly = { diff --git a/net/ipv4/tcp_westwood.c b/net/ipv4/tcp_westwood.c index b2e05c4cea00..c6e97141eef2 100644 --- a/net/ipv4/tcp_westwood.c +++ b/net/ipv4/tcp_westwood.c @@ -244,7 +244,8 @@ static void tcp_westwood_event(struct sock *sk, enum tcp_ca_event event)
switch (event) { case CA_EVENT_COMPLETE_CWR: - tp->snd_cwnd = tp->snd_ssthresh = tcp_westwood_bw_rttmin(sk); + tp->snd_ssthresh = tcp_westwood_bw_rttmin(sk); + tcp_snd_cwnd_set(tp, tp->snd_ssthresh); break; case CA_EVENT_LOSS: tp->snd_ssthresh = tcp_westwood_bw_rttmin(sk); diff --git a/net/ipv4/tcp_yeah.c b/net/ipv4/tcp_yeah.c index 07c4c93b9fdb..18b07ff5d20e 100644 --- a/net/ipv4/tcp_yeah.c +++ b/net/ipv4/tcp_yeah.c @@ -71,11 +71,11 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack, u32 acked)
if (!yeah->doing_reno_now) { /* Scalable */ - tcp_cong_avoid_ai(tp, min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT), + tcp_cong_avoid_ai(tp, min(tcp_snd_cwnd(tp), TCP_SCALABLE_AI_CNT), acked); } else { /* Reno */ - tcp_cong_avoid_ai(tp, tp->snd_cwnd, acked); + tcp_cong_avoid_ai(tp, tcp_snd_cwnd(tp), acked); }
/* The key players are v_vegas.beg_snd_una and v_beg_snd_nxt. @@ -130,7 +130,7 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack, u32 acked) /* Compute excess number of packets above bandwidth * Avoid doing full 64 bit divide. */ - bw = tp->snd_cwnd; + bw = tcp_snd_cwnd(tp); bw *= rtt - yeah->vegas.baseRTT; do_div(bw, rtt); queue = bw; @@ -138,20 +138,20 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack, u32 acked) if (queue > TCP_YEAH_ALPHA || rtt - yeah->vegas.baseRTT > (yeah->vegas.baseRTT / TCP_YEAH_PHY)) { if (queue > TCP_YEAH_ALPHA && - tp->snd_cwnd > yeah->reno_count) { + tcp_snd_cwnd(tp) > yeah->reno_count) { u32 reduction = min(queue / TCP_YEAH_GAMMA , - tp->snd_cwnd >> TCP_YEAH_EPSILON); + tcp_snd_cwnd(tp) >> TCP_YEAH_EPSILON);
- tp->snd_cwnd -= reduction; + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) - reduction);
- tp->snd_cwnd = max(tp->snd_cwnd, - yeah->reno_count); + tcp_snd_cwnd_set(tp, max(tcp_snd_cwnd(tp), + yeah->reno_count));
- tp->snd_ssthresh = tp->snd_cwnd; + tp->snd_ssthresh = tcp_snd_cwnd(tp); }
if (yeah->reno_count <= 2) - yeah->reno_count = max(tp->snd_cwnd>>1, 2U); + yeah->reno_count = max(tcp_snd_cwnd(tp)>>1, 2U); else yeah->reno_count++;
@@ -176,7 +176,7 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack, u32 acked) */ yeah->vegas.beg_snd_una = yeah->vegas.beg_snd_nxt; yeah->vegas.beg_snd_nxt = tp->snd_nxt; - yeah->vegas.beg_snd_cwnd = tp->snd_cwnd; + yeah->vegas.beg_snd_cwnd = tcp_snd_cwnd(tp);
/* Wipe the slate clean for the next RTT. */ yeah->vegas.cntRTT = 0; @@ -193,16 +193,16 @@ static u32 tcp_yeah_ssthresh(struct sock *sk) if (yeah->doing_reno_now < TCP_YEAH_RHO) { reduction = yeah->lastQ;
- reduction = min(reduction, max(tp->snd_cwnd>>1, 2U)); + reduction = min(reduction, max(tcp_snd_cwnd(tp)>>1, 2U));
- reduction = max(reduction, tp->snd_cwnd >> TCP_YEAH_DELTA); + reduction = max(reduction, tcp_snd_cwnd(tp) >> TCP_YEAH_DELTA); } else - reduction = max(tp->snd_cwnd>>1, 2U); + reduction = max(tcp_snd_cwnd(tp)>>1, 2U);
yeah->fast_count = 0; yeah->reno_count = max(yeah->reno_count>>1, 2U);
- return max_t(int, tp->snd_cwnd - reduction, 2); + return max_t(int, tcp_snd_cwnd(tp) - reduction, 2); }
static struct tcp_congestion_ops tcp_yeah __read_mostly = { diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index faaddaf43c90..cbc5fff3d846 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -2044,7 +2044,7 @@ static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i) jiffies_to_clock_t(icsk->icsk_rto), jiffies_to_clock_t(icsk->icsk_ack.ato), (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sp), - tp->snd_cwnd, + tcp_snd_cwnd(tp), state == TCP_LISTEN ? fastopenq->max_qlen : (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)