From 4aabd8ef8c43677cfee3e1e36c5a79edddb41942 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Mon, 9 Jul 2012 16:07:30 -0700 Subject: tcp: Move dynamnic metrics handling into seperate file. Signed-off-by: David S. Miller --- net/ipv4/tcp_metrics.c | 192 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 192 insertions(+) create mode 100644 net/ipv4/tcp_metrics.c (limited to 'net/ipv4/tcp_metrics.c') diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c new file mode 100644 index 000000000000..2793ecf928d3 --- /dev/null +++ b/net/ipv4/tcp_metrics.c @@ -0,0 +1,192 @@ +#include +#include + +#include +#include +#include +#include + +int sysctl_tcp_nometrics_save __read_mostly; + +/* Save metrics learned by this TCP session. This function is called + * only, when TCP finishes successfully i.e. when it enters TIME-WAIT + * or goes from LAST-ACK to CLOSE. + */ +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; + + if (dst && (dst->flags & DST_HOST)) { + const struct inet_connection_sock *icsk = inet_csk(sk); + int m; + unsigned long rtt; + + dst_confirm(dst); + + if (icsk->icsk_backoff || !tp->srtt) { + /* This session failed to estimate rtt. Why? + * Probably, no packets returned in time. + * Reset our results. + */ + 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 newly calculated rtt larger than stored one, + * store new one. Otherwise, use EWMA. Remember, + * rtt overestimation is always better than underestimation. + */ + 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; + + /* Scale deviation to rttvar fixed point */ + 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)) { + /* Slow start still did not finish. */ + 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) { + /* Cong. avoidance phase, cwnd is reliable. */ + 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 { + /* Else slow start did not finish, cwnd is non-sense, + ssthresh may be also invalid. + */ + 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); + } + } +} + +/* Initialize metrics on socket. */ + +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 { + /* ssthresh may have been reduced unnecessarily during. + * 3WHS. Restore it back to its initial default. + */ + tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; + } + if (dst_metric(dst, RTAX_REORDERING) && + tp->reordering != dst_metric(dst, RTAX_REORDERING)) { + tcp_disable_fack(tp); + tcp_disable_early_retrans(tp); + tp->reordering = dst_metric(dst, RTAX_REORDERING); + } + + if (dst_metric(dst, RTAX_RTT) == 0 || tp->srtt == 0) + goto reset; + + /* Initial rtt is determined from SYN,SYN-ACK. + * The segment is small and rtt may appear much + * less than real one. Use per-dst memory + * to make it more realistic. + * + * A bit of theory. RTT is time passed after "normal" sized packet + * is sent until it is ACKed. In normal circumstances sending small + * packets force peer to delay ACKs and calculation is correct too. + * The algorithm is adaptive and, provided we follow specs, it + * NEVER underestimate RTT. BUT! If peer tries to make some clever + * tricks sort of "quick acks" for time long enough to decrease RTT + * to low value, and then abruptly stops to do it and starts to delay + * ACKs, wait for troubles. + */ + 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) { + /* RFC6298: 5.7 We've failed to get a valid RTT sample from + * 3WHS. This is most likely due to retransmission, + * including spurious one. Reset the RTO back to 3secs + * from the more aggressive 1sec to avoid more spurious + * retransmission. + */ + tp->mdev = tp->mdev_max = tp->rttvar = TCP_TIMEOUT_FALLBACK; + inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK; + } + /* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been + * retransmitted. In light of RFC6298 more aggressive 1sec + * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK + * retransmission has occurred. + */ + 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; +} -- cgit v1.2.3 From ab92bb2f679d66c7e12a6b1c0cdd76fe308f6546 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Mon, 9 Jul 2012 16:19:30 -0700 Subject: tcp: Abstract back handling peer aliveness test into helper function. Signed-off-by: David S. Miller --- net/ipv4/tcp_metrics.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'net/ipv4/tcp_metrics.c') diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 2793ecf928d3..9afe703c85cc 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -1,7 +1,9 @@ +#include #include #include #include +#include #include #include #include @@ -190,3 +192,11 @@ reset: tp->snd_cwnd = tcp_init_cwnd(tp, dst); tp->snd_cwnd_stamp = tcp_time_stamp; } + +bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst) +{ + if (!dst) + return false; + return dst_metric(dst, RTAX_RTT) ? true : false; +} +EXPORT_SYMBOL_GPL(tcp_peer_is_proven); -- cgit v1.2.3 From 51c5d0c4b169bf762f09e0d5b283a7f0b2a45739 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Tue, 10 Jul 2012 00:49:14 -0700 Subject: tcp: Maintain dynamic metrics in local cache. Maintain a local hash table of TCP dynamic metrics blobs. Computed TCP metrics are no longer maintained in the route metrics. The table uses RCU and an extremely simple hash so that it has low latency and low overhead. A simple hash is legitimate because we only make metrics blobs for fully established connections. Some tweaking of the default hash table sizes, metric timeouts, and the hash chain length limit certainly could use some tweaking. But the basic design seems sound. With help from Eric Dumazet and Joe Perches. Signed-off-by: David S. Miller --- net/ipv4/tcp_metrics.c | 555 ++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 462 insertions(+), 93 deletions(-) (limited to 'net/ipv4/tcp_metrics.c') diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 9afe703c85cc..56223bab251b 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -1,134 +1,431 @@ +#include +#include +#include +#include #include #include +#include +#include #include #include +#include #include +#include #include +#include #include #include int sysctl_tcp_nometrics_save __read_mostly; +enum tcp_metric_index { + TCP_METRIC_RTT, + TCP_METRIC_RTTVAR, + TCP_METRIC_SSTHRESH, + TCP_METRIC_CWND, + TCP_METRIC_REORDERING, + + /* Always last. */ + TCP_METRIC_MAX, +}; + +struct tcp_metrics_block { + struct tcp_metrics_block __rcu *tcpm_next; + struct inetpeer_addr tcpm_addr; + unsigned long tcpm_stamp; + u32 tcpm_lock; + u32 tcpm_vals[TCP_METRIC_MAX]; +}; + +static bool tcp_metric_locked(struct tcp_metrics_block *tm, + enum tcp_metric_index idx) +{ + return tm->tcpm_lock & (1 << idx); +} + +static u32 tcp_metric_get(struct tcp_metrics_block *tm, + enum tcp_metric_index idx) +{ + return tm->tcpm_vals[idx]; +} + +static u32 tcp_metric_get_jiffies(struct tcp_metrics_block *tm, + enum tcp_metric_index idx) +{ + return msecs_to_jiffies(tm->tcpm_vals[idx]); +} + +static void tcp_metric_set(struct tcp_metrics_block *tm, + enum tcp_metric_index idx, + u32 val) +{ + tm->tcpm_vals[idx] = val; +} + +static void tcp_metric_set_msecs(struct tcp_metrics_block *tm, + enum tcp_metric_index idx, + u32 val) +{ + tm->tcpm_vals[idx] = jiffies_to_msecs(val); +} + +static bool addr_same(const struct inetpeer_addr *a, + const struct inetpeer_addr *b) +{ + const struct in6_addr *a6, *b6; + + if (a->family != b->family) + return false; + if (a->family == AF_INET) + return a->addr.a4 == b->addr.a4; + + a6 = (const struct in6_addr *) &a->addr.a6[0]; + b6 = (const struct in6_addr *) &b->addr.a6[0]; + + return ipv6_addr_equal(a6, b6); +} + +struct tcpm_hash_bucket { + struct tcp_metrics_block __rcu *chain; +}; + +static DEFINE_SPINLOCK(tcp_metrics_lock); + +static void tcpm_suck_dst(struct tcp_metrics_block *tm, struct dst_entry *dst) +{ + u32 val; + + val = 0; + if (dst_metric_locked(dst, RTAX_RTT)) + val |= 1 << TCP_METRIC_RTT; + if (dst_metric_locked(dst, RTAX_RTTVAR)) + val |= 1 << TCP_METRIC_RTTVAR; + if (dst_metric_locked(dst, RTAX_SSTHRESH)) + val |= 1 << TCP_METRIC_SSTHRESH; + if (dst_metric_locked(dst, RTAX_CWND)) + val |= 1 << TCP_METRIC_CWND; + if (dst_metric_locked(dst, RTAX_REORDERING)) + val |= 1 << TCP_METRIC_REORDERING; + tm->tcpm_lock = val; + + tm->tcpm_vals[TCP_METRIC_RTT] = dst_metric_raw(dst, RTAX_RTT); + tm->tcpm_vals[TCP_METRIC_RTTVAR] = dst_metric_raw(dst, RTAX_RTTVAR); + tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH); + tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND); + tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING); +} + +static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, + struct inetpeer_addr *addr, + unsigned int hash, + bool reclaim) +{ + struct tcp_metrics_block *tm; + struct net *net; + + spin_lock_bh(&tcp_metrics_lock); + net = dev_net(dst->dev); + if (unlikely(reclaim)) { + struct tcp_metrics_block *oldest; + + oldest = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); + for (tm = rcu_dereference(oldest->tcpm_next); tm; + tm = rcu_dereference(tm->tcpm_next)) { + if (time_before(tm->tcpm_stamp, oldest->tcpm_stamp)) + oldest = tm; + } + tm = oldest; + } else { + tm = kmalloc(sizeof(*tm), GFP_ATOMIC); + if (!tm) + goto out_unlock; + } + tm->tcpm_addr = *addr; + tm->tcpm_stamp = jiffies; + + tcpm_suck_dst(tm, dst); + + if (likely(!reclaim)) { + tm->tcpm_next = net->ipv4.tcp_metrics_hash[hash].chain; + rcu_assign_pointer(net->ipv4.tcp_metrics_hash[hash].chain, tm); + } + +out_unlock: + spin_unlock_bh(&tcp_metrics_lock); + return tm; +} + +#define TCP_METRICS_TIMEOUT (60 * 60 * HZ) + +static void tcpm_check_stamp(struct tcp_metrics_block *tm, struct dst_entry *dst) +{ + if (tm && unlikely(time_after(jiffies, tm->tcpm_stamp + TCP_METRICS_TIMEOUT))) + tcpm_suck_dst(tm, dst); +} + +#define TCP_METRICS_RECLAIM_DEPTH 5 +#define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL + +static struct tcp_metrics_block *tcp_get_encode(struct tcp_metrics_block *tm, int depth) +{ + if (tm) + return tm; + if (depth > TCP_METRICS_RECLAIM_DEPTH) + return TCP_METRICS_RECLAIM_PTR; + return NULL; +} + +static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *addr, + struct net *net, unsigned int hash) +{ + struct tcp_metrics_block *tm; + int depth = 0; + + for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; + tm = rcu_dereference(tm->tcpm_next)) { + if (addr_same(&tm->tcpm_addr, addr)) + break; + depth++; + } + return tcp_get_encode(tm, depth); +} + +static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req, + struct dst_entry *dst) +{ + struct tcp_metrics_block *tm; + struct inetpeer_addr addr; + unsigned int hash; + struct net *net; + + addr.family = req->rsk_ops->family; + switch (addr.family) { + case AF_INET: + addr.addr.a4 = inet_rsk(req)->rmt_addr; + hash = (__force unsigned int) addr.addr.a4; + break; + case AF_INET6: + *(struct in6_addr *)addr.addr.a6 = inet6_rsk(req)->rmt_addr; + hash = ((__force unsigned int) addr.addr.a6[0] ^ + (__force unsigned int) addr.addr.a6[1] ^ + (__force unsigned int) addr.addr.a6[2] ^ + (__force unsigned int) addr.addr.a6[3]); + break; + default: + return NULL; + } + + hash ^= (hash >> 24) ^ (hash >> 16) ^ (hash >> 8); + + net = dev_net(dst->dev); + hash &= net->ipv4.tcp_metrics_hash_mask; + + for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; + tm = rcu_dereference(tm->tcpm_next)) { + if (addr_same(&tm->tcpm_addr, &addr)) + break; + } + tcpm_check_stamp(tm, dst); + return tm; +} + +static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk, + struct dst_entry *dst, + bool create) +{ + struct tcp_metrics_block *tm; + struct inetpeer_addr addr; + unsigned int hash; + struct net *net; + bool reclaim; + + addr.family = sk->sk_family; + switch (addr.family) { + case AF_INET: + addr.addr.a4 = inet_sk(sk)->inet_daddr; + hash = (__force unsigned int) addr.addr.a4; + break; + case AF_INET6: + *(struct in6_addr *)addr.addr.a6 = inet6_sk(sk)->daddr; + hash = ((__force unsigned int) addr.addr.a6[0] ^ + (__force unsigned int) addr.addr.a6[1] ^ + (__force unsigned int) addr.addr.a6[2] ^ + (__force unsigned int) addr.addr.a6[3]); + break; + default: + return NULL; + } + + hash ^= (hash >> 24) ^ (hash >> 16) ^ (hash >> 8); + + net = dev_net(dst->dev); + hash &= net->ipv4.tcp_metrics_hash_mask; + + tm = __tcp_get_metrics(&addr, net, hash); + reclaim = false; + if (tm == TCP_METRICS_RECLAIM_PTR) { + reclaim = true; + tm = NULL; + } + if (!tm && create) + tm = tcpm_new(dst, &addr, hash, reclaim); + else + tcpm_check_stamp(tm, dst); + + return tm; +} + /* Save metrics learned by this TCP session. This function is called * only, when TCP finishes successfully i.e. when it enters TIME-WAIT * or goes from LAST-ACK to CLOSE. */ void tcp_update_metrics(struct sock *sk) { - struct tcp_sock *tp = tcp_sk(sk); + const struct inet_connection_sock *icsk = inet_csk(sk); struct dst_entry *dst = __sk_dst_get(sk); + struct tcp_sock *tp = tcp_sk(sk); + struct tcp_metrics_block *tm; + unsigned long rtt; + u32 val; + int m; - if (sysctl_tcp_nometrics_save) + if (sysctl_tcp_nometrics_save || !dst) return; - if (dst && (dst->flags & DST_HOST)) { - const struct inet_connection_sock *icsk = inet_csk(sk); - int m; - unsigned long rtt; - + if (dst->flags & DST_HOST) dst_confirm(dst); - if (icsk->icsk_backoff || !tp->srtt) { - /* This session failed to estimate rtt. Why? - * Probably, no packets returned in time. - * Reset our results. - */ - if (!(dst_metric_locked(dst, RTAX_RTT))) - dst_metric_set(dst, RTAX_RTT, 0); - return; - } + rcu_read_lock(); + if (icsk->icsk_backoff || !tp->srtt) { + /* This session failed to estimate rtt. Why? + * Probably, no packets returned in time. Reset our + * results. + */ + tm = tcp_get_metrics(sk, dst, false); + if (tm && !tcp_metric_locked(tm, TCP_METRIC_RTT)) + tcp_metric_set(tm, TCP_METRIC_RTT, 0); + goto out_unlock; + } else + tm = tcp_get_metrics(sk, dst, true); - rtt = dst_metric_rtt(dst, RTAX_RTT); - m = rtt - tp->srtt; + if (!tm) + goto out_unlock; - /* If newly calculated rtt larger than stored one, - * store new one. Otherwise, use EWMA. Remember, - * rtt overestimation is always better than underestimation. - */ - 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)); - } + rtt = tcp_metric_get_jiffies(tm, TCP_METRIC_RTT); + m = rtt - tp->srtt; - if (!(dst_metric_locked(dst, RTAX_RTTVAR))) { - unsigned long var; - if (m < 0) - m = -m; + /* If newly calculated rtt larger than stored one, store new + * one. Otherwise, use EWMA. Remember, rtt overestimation is + * always better than underestimation. + */ + if (!tcp_metric_locked(tm, TCP_METRIC_RTT)) { + if (m <= 0) + rtt = tp->srtt; + else + rtt -= (m >> 3); + tcp_metric_set_msecs(tm, TCP_METRIC_RTT, rtt); + } - /* Scale deviation to rttvar fixed point */ - m >>= 1; - if (m < tp->mdev) - m = tp->mdev; + if (!tcp_metric_locked(tm, TCP_METRIC_RTTVAR)) { + unsigned long var; - var = dst_metric_rtt(dst, RTAX_RTTVAR); - if (m >= var) - var = m; - else - var -= (var - m) >> 2; + if (m < 0) + m = -m; - set_dst_metric_rtt(dst, RTAX_RTTVAR, var); - } + /* Scale deviation to rttvar fixed point */ + m >>= 1; + if (m < tp->mdev) + m = tp->mdev; - if (tcp_in_initial_slowstart(tp)) { - /* Slow start still did not finish. */ - 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) { - /* Cong. avoidance phase, cwnd is reliable. */ - 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 { - /* Else slow start did not finish, cwnd is non-sense, - ssthresh may be also invalid. - */ - 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); - } + var = tcp_metric_get_jiffies(tm, TCP_METRIC_RTTVAR); + if (m >= var) + var = m; + else + var -= (var - m) >> 2; - if (!dst_metric_locked(dst, RTAX_REORDERING)) { - if (dst_metric(dst, RTAX_REORDERING) < tp->reordering && + tcp_metric_set_msecs(tm, TCP_METRIC_RTTVAR, var); + } + + if (tcp_in_initial_slowstart(tp)) { + /* Slow start still did not finish. */ + if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { + val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); + if (val && (tp->snd_cwnd >> 1) > val) + tcp_metric_set(tm, TCP_METRIC_SSTHRESH, + tp->snd_cwnd >> 1); + } + if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { + val = tcp_metric_get(tm, TCP_METRIC_CWND); + if (tp->snd_cwnd > val) + tcp_metric_set(tm, TCP_METRIC_CWND, + tp->snd_cwnd); + } + } else if (tp->snd_cwnd > tp->snd_ssthresh && + icsk->icsk_ca_state == TCP_CA_Open) { + /* Cong. avoidance phase, cwnd is reliable. */ + if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) + tcp_metric_set(tm, TCP_METRIC_SSTHRESH, + max(tp->snd_cwnd >> 1, tp->snd_ssthresh)); + if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { + val = tcp_metric_get(tm, TCP_METRIC_CWND); + tcp_metric_set(tm, RTAX_CWND, (val + tp->snd_cwnd) >> 1); + } + } else { + /* Else slow start did not finish, cwnd is non-sense, + * ssthresh may be also invalid. + */ + 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_ssthresh) >> 1); + } + if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { + val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); + if (val && tp->snd_ssthresh > val) + tcp_metric_set(tm, TCP_METRIC_SSTHRESH, + tp->snd_ssthresh); + } + if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) { + val = tcp_metric_get(tm, TCP_METRIC_REORDERING); + if (val < tp->reordering && tp->reordering != sysctl_tcp_reordering) - dst_metric_set(dst, RTAX_REORDERING, tp->reordering); + tcp_metric_set(tm, TCP_METRIC_REORDERING, + tp->reordering); } } + tm->tcpm_stamp = jiffies; +out_unlock: + rcu_read_unlock(); } /* Initialize metrics on socket. */ void tcp_init_metrics(struct sock *sk) { - struct tcp_sock *tp = tcp_sk(sk); struct dst_entry *dst = __sk_dst_get(sk); + struct tcp_sock *tp = tcp_sk(sk); + struct tcp_metrics_block *tm; + u32 val; 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); + rcu_read_lock(); + tm = tcp_get_metrics(sk, dst, true); + if (!tm) { + rcu_read_unlock(); + goto reset; + } + + if (tcp_metric_locked(tm, TCP_METRIC_CWND)) + tp->snd_cwnd_clamp = tcp_metric_get(tm, TCP_METRIC_CWND); + + val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); + if (val) { + tp->snd_ssthresh = val; if (tp->snd_ssthresh > tp->snd_cwnd_clamp) tp->snd_ssthresh = tp->snd_cwnd_clamp; } else { @@ -137,16 +434,18 @@ void tcp_init_metrics(struct sock *sk) */ tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; } - if (dst_metric(dst, RTAX_REORDERING) && - tp->reordering != dst_metric(dst, RTAX_REORDERING)) { + val = tcp_metric_get(tm, TCP_METRIC_REORDERING); + if (val && tp->reordering != val) { tcp_disable_fack(tp); tcp_disable_early_retrans(tp); - tp->reordering = dst_metric(dst, RTAX_REORDERING); + tp->reordering = val; } - if (dst_metric(dst, RTAX_RTT) == 0 || tp->srtt == 0) + val = tcp_metric_get(tm, TCP_METRIC_RTT); + if (val == 0 || tp->srtt == 0) { + rcu_read_unlock(); goto reset; - + } /* Initial rtt is determined from SYN,SYN-ACK. * The segment is small and rtt may appear much * less than real one. Use per-dst memory @@ -161,14 +460,18 @@ void tcp_init_metrics(struct sock *sk) * to low value, and then abruptly stops to do it and starts to delay * ACKs, wait for troubles. */ - if (dst_metric_rtt(dst, RTAX_RTT) > tp->srtt) { - tp->srtt = dst_metric_rtt(dst, RTAX_RTT); + val = msecs_to_jiffies(val); + if (val > tp->srtt) { + tp->srtt = val; tp->rtt_seq = tp->snd_nxt; } - if (dst_metric_rtt(dst, RTAX_RTTVAR) > tp->mdev) { - tp->mdev = dst_metric_rtt(dst, RTAX_RTTVAR); + val = tcp_metric_get_jiffies(tm, TCP_METRIC_RTTVAR); + if (val > tp->mdev) { + tp->mdev = val; tp->mdev_max = tp->rttvar = max(tp->mdev, tcp_rto_min(sk)); } + rcu_read_unlock(); + tcp_set_rto(sk); reset: if (tp->srtt == 0) { @@ -195,8 +498,74 @@ reset: bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst) { + struct tcp_metrics_block *tm; + bool ret; + if (!dst) return false; - return dst_metric(dst, RTAX_RTT) ? true : false; + + rcu_read_lock(); + tm = __tcp_get_metrics_req(req, dst); + if (tm && tcp_metric_get(tm, TCP_METRIC_RTT)) + ret = true; + else + ret = false; + rcu_read_unlock(); + + return ret; } EXPORT_SYMBOL_GPL(tcp_peer_is_proven); + +static unsigned long tcpmhash_entries; +static int __init set_tcpmhash_entries(char *str) +{ + ssize_t ret; + + if (!str) + return 0; + + ret = kstrtoul(str, 0, &tcpmhash_entries); + if (ret) + return 0; + + return 1; +} +__setup("tcpmhash_entries=", set_tcpmhash_entries); + +static int __net_init tcp_net_metrics_init(struct net *net) +{ + int slots, size; + + slots = tcpmhash_entries; + if (!slots) { + if (totalram_pages >= 128 * 1024) + slots = 16 * 1024; + else + slots = 8 * 1024; + } + + size = slots * sizeof(struct tcpm_hash_bucket); + + net->ipv4.tcp_metrics_hash = kzalloc(size, GFP_KERNEL); + if (!net->ipv4.tcp_metrics_hash) + return -ENOMEM; + + net->ipv4.tcp_metrics_hash_mask = (slots - 1); + + return 0; +} + +static void __net_exit tcp_net_metrics_exit(struct net *net) +{ + kfree(net->ipv4.tcp_metrics_hash); +} + +static __net_initdata struct pernet_operations tcp_net_metrics_ops = { + .init = tcp_net_metrics_init, + .exit = tcp_net_metrics_exit, +}; + +void __init tcp_metrics_init(void) +{ + register_pernet_subsys(&tcp_net_metrics_ops); +} -- cgit v1.2.3 From 81166dd6fa8eb780b2132d32fbc77eb6ac04e44e Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Tue, 10 Jul 2012 03:14:24 -0700 Subject: tcp: Move timestamps from inetpeer to metrics cache. With help from Lin Ming. Signed-off-by: David S. Miller --- net/ipv4/tcp_metrics.c | 136 +++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 131 insertions(+), 5 deletions(-) (limited to 'net/ipv4/tcp_metrics.c') diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 56223bab251b..1fd83d3118fe 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -34,6 +34,8 @@ struct tcp_metrics_block { struct tcp_metrics_block __rcu *tcpm_next; struct inetpeer_addr tcpm_addr; unsigned long tcpm_stamp; + u32 tcpm_ts; + u32 tcpm_ts_stamp; u32 tcpm_lock; u32 tcpm_vals[TCP_METRIC_MAX]; }; @@ -114,6 +116,8 @@ static void tcpm_suck_dst(struct tcp_metrics_block *tm, struct dst_entry *dst) tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH); tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND); tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING); + tm->tcpm_ts = 0; + tm->tcpm_ts_stamp = 0; } static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, @@ -230,6 +234,45 @@ static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req, return tm; } +static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock *tw) +{ + struct inet6_timewait_sock *tw6; + struct tcp_metrics_block *tm; + struct inetpeer_addr addr; + unsigned int hash; + struct net *net; + + addr.family = tw->tw_family; + switch (addr.family) { + case AF_INET: + addr.addr.a4 = tw->tw_daddr; + hash = (__force unsigned int) addr.addr.a4; + break; + case AF_INET6: + tw6 = inet6_twsk((struct sock *)tw); + *(struct in6_addr *)addr.addr.a6 = tw6->tw_v6_daddr; + hash = ((__force unsigned int) addr.addr.a6[0] ^ + (__force unsigned int) addr.addr.a6[1] ^ + (__force unsigned int) addr.addr.a6[2] ^ + (__force unsigned int) addr.addr.a6[3]); + break; + default: + return NULL; + } + + hash ^= (hash >> 24) ^ (hash >> 16) ^ (hash >> 8); + + net = twsk_net(tw); + hash &= net->ipv4.tcp_metrics_hash_mask; + + for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; + tm = rcu_dereference(tm->tcpm_next)) { + if (addr_same(&tm->tcpm_addr, &addr)) + break; + } + return tm; +} + static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk, struct dst_entry *dst, bool create) @@ -496,7 +539,7 @@ reset: tp->snd_cwnd_stamp = tcp_time_stamp; } -bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst) +bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, bool paws_check) { struct tcp_metrics_block *tm; bool ret; @@ -506,16 +549,99 @@ bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst) rcu_read_lock(); tm = __tcp_get_metrics_req(req, dst); - if (tm && tcp_metric_get(tm, TCP_METRIC_RTT)) - ret = true; - else - ret = false; + if (paws_check) { + if (tm && + (u32)get_seconds() - tm->tcpm_ts_stamp < TCP_PAWS_MSL && + (s32)(tm->tcpm_ts - req->ts_recent) > TCP_PAWS_WINDOW) + ret = false; + else + ret = true; + } else { + if (tm && tcp_metric_get(tm, TCP_METRIC_RTT) && tm->tcpm_ts_stamp) + ret = true; + else + ret = false; + } rcu_read_unlock(); return ret; } EXPORT_SYMBOL_GPL(tcp_peer_is_proven); +void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst) +{ + struct tcp_metrics_block *tm; + + rcu_read_lock(); + tm = tcp_get_metrics(sk, dst, true); + if (tm) { + struct tcp_sock *tp = tcp_sk(sk); + + if ((u32)get_seconds() - tm->tcpm_ts_stamp <= TCP_PAWS_MSL) { + tp->rx_opt.ts_recent_stamp = tm->tcpm_ts_stamp; + tp->rx_opt.ts_recent = tm->tcpm_ts; + } + } + rcu_read_unlock(); +} +EXPORT_SYMBOL_GPL(tcp_fetch_timewait_stamp); + +/* VJ's idea. Save last timestamp seen from this destination and hold + * it at least for normal timewait interval to use for duplicate + * segment detection in subsequent connections, before they enter + * synchronized state. + */ +bool tcp_remember_stamp(struct sock *sk) +{ + struct dst_entry *dst = __sk_dst_get(sk); + bool ret = false; + + if (dst) { + struct tcp_metrics_block *tm; + + rcu_read_lock(); + tm = tcp_get_metrics(sk, dst, true); + if (tm) { + struct tcp_sock *tp = tcp_sk(sk); + + if ((s32)(tm->tcpm_ts - tp->rx_opt.ts_recent) <= 0 || + ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL && + tm->tcpm_ts_stamp <= (u32)tp->rx_opt.ts_recent_stamp)) { + tm->tcpm_ts_stamp = (u32)tp->rx_opt.ts_recent_stamp; + tm->tcpm_ts = tp->rx_opt.ts_recent; + } + ret = true; + } + rcu_read_unlock(); + } + return ret; +} + +bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw) +{ + struct tcp_metrics_block *tm; + bool ret = false; + + rcu_read_lock(); + tm = __tcp_get_metrics_tw(tw); + if (tw) { + const struct tcp_timewait_sock *tcptw; + struct sock *sk = (struct sock *) tw; + + tcptw = tcp_twsk(sk); + if ((s32)(tm->tcpm_ts - tcptw->tw_ts_recent) <= 0 || + ((u32)get_seconds() - tm->tcpm_ts_stamp > TCP_PAWS_MSL && + tm->tcpm_ts_stamp <= (u32)tcptw->tw_ts_recent_stamp)) { + tm->tcpm_ts_stamp = (u32)tcptw->tw_ts_recent_stamp; + tm->tcpm_ts = tcptw->tw_ts_recent; + } + ret = true; + } + rcu_read_unlock(); + + return ret; +} + static unsigned long tcpmhash_entries; static int __init set_tcpmhash_entries(char *str) { -- cgit v1.2.3 From 2100844ca9d7055d5cddce2f8ed13af94c01f85b Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Wed, 11 Jul 2012 17:18:04 -0700 Subject: tcp: Fix out of bounds access to tcpm_vals The recent patch "tcp: Maintain dynamic metrics in local cache." introduced an out of bounds access due to what appears to be a typo. I believe this change should resolve the issue by replacing the access to RTAX_CWND with TCP_METRIC_CWND. Signed-off-by: Alexander Duyck Signed-off-by: David S. Miller --- net/ipv4/tcp_metrics.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/ipv4/tcp_metrics.c') diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 1fd83d3118fe..5a38a2d5a95b 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -412,7 +412,7 @@ void tcp_update_metrics(struct sock *sk) max(tp->snd_cwnd >> 1, tp->snd_ssthresh)); if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { val = tcp_metric_get(tm, TCP_METRIC_CWND); - tcp_metric_set(tm, RTAX_CWND, (val + tp->snd_cwnd) >> 1); + tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1); } } else { /* Else slow start did not finish, cwnd is non-sense, -- cgit v1.2.3 From ddbe503203855939946430e39bae58de11b70b69 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 18 Jul 2012 08:11:12 +0000 Subject: ipv6: add ipv6_addr_hash() helper Introduce ipv6_addr_hash() helper doing a XOR on all bits of an IPv6 address, with an optimized x86_64 version. Use it in flow dissector, as suggested by Andrew McGregor, to reduce hash collision probabilities in fq_codel (and other users of flow dissector) Use it in ip6_tunnel.c and use more bit shuffling, as suggested by David Laight, as existing hash was ignoring most of them. Use it in sunrpc and use more bit shuffling, using hash_32(). Use it in net/ipv6/addrconf.c, using hash_32() as well. As a cleanup, use it in net/ipv4/tcp_metrics.c Signed-off-by: Eric Dumazet Reported-by: Andrew McGregor Cc: Dave Taht Cc: Tom Herbert Cc: David Laight Cc: Joe Perches Signed-off-by: David S. Miller --- net/ipv4/tcp_metrics.c | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-) (limited to 'net/ipv4/tcp_metrics.c') diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 5a38a2d5a95b..1a115b665792 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -211,10 +211,7 @@ static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req, break; case AF_INET6: *(struct in6_addr *)addr.addr.a6 = inet6_rsk(req)->rmt_addr; - hash = ((__force unsigned int) addr.addr.a6[0] ^ - (__force unsigned int) addr.addr.a6[1] ^ - (__force unsigned int) addr.addr.a6[2] ^ - (__force unsigned int) addr.addr.a6[3]); + hash = ipv6_addr_hash(&inet6_rsk(req)->rmt_addr); break; default: return NULL; @@ -251,10 +248,7 @@ static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock case AF_INET6: tw6 = inet6_twsk((struct sock *)tw); *(struct in6_addr *)addr.addr.a6 = tw6->tw_v6_daddr; - hash = ((__force unsigned int) addr.addr.a6[0] ^ - (__force unsigned int) addr.addr.a6[1] ^ - (__force unsigned int) addr.addr.a6[2] ^ - (__force unsigned int) addr.addr.a6[3]); + hash = ipv6_addr_hash(&tw6->tw_v6_daddr); break; default: return NULL; @@ -291,10 +285,7 @@ static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk, break; case AF_INET6: *(struct in6_addr *)addr.addr.a6 = inet6_sk(sk)->daddr; - hash = ((__force unsigned int) addr.addr.a6[0] ^ - (__force unsigned int) addr.addr.a6[1] ^ - (__force unsigned int) addr.addr.a6[2] ^ - (__force unsigned int) addr.addr.a6[3]); + hash = ipv6_addr_hash(&inet6_sk(sk)->daddr); break; default: return NULL; -- cgit v1.2.3 From 1fe4c481ba637660793217769695c146a037bd54 Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Thu, 19 Jul 2012 06:43:06 +0000 Subject: net-tcp: Fast Open client - cookie cache With help from Eric Dumazet, add Fast Open metrics in tcp metrics cache. The basic ones are MSS and the cookies. Later patch will cache more to handle unfriendly middleboxes. Signed-off-by: Yuchung Cheng Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_metrics.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) (limited to 'net/ipv4/tcp_metrics.c') diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 1a115b665792..d02ff3777785 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -30,6 +30,11 @@ enum tcp_metric_index { TCP_METRIC_MAX, }; +struct tcp_fastopen_metrics { + u16 mss; + struct tcp_fastopen_cookie cookie; +}; + struct tcp_metrics_block { struct tcp_metrics_block __rcu *tcpm_next; struct inetpeer_addr tcpm_addr; @@ -38,6 +43,7 @@ struct tcp_metrics_block { u32 tcpm_ts_stamp; u32 tcpm_lock; u32 tcpm_vals[TCP_METRIC_MAX]; + struct tcp_fastopen_metrics tcpm_fastopen; }; static bool tcp_metric_locked(struct tcp_metrics_block *tm, @@ -118,6 +124,8 @@ static void tcpm_suck_dst(struct tcp_metrics_block *tm, struct dst_entry *dst) tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING); tm->tcpm_ts = 0; tm->tcpm_ts_stamp = 0; + tm->tcpm_fastopen.mss = 0; + tm->tcpm_fastopen.cookie.len = 0; } static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, @@ -633,6 +641,49 @@ bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw) return ret; } +static DEFINE_SEQLOCK(fastopen_seqlock); + +void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, + struct tcp_fastopen_cookie *cookie) +{ + struct tcp_metrics_block *tm; + + rcu_read_lock(); + tm = tcp_get_metrics(sk, __sk_dst_get(sk), false); + if (tm) { + struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; + unsigned int seq; + + do { + seq = read_seqbegin(&fastopen_seqlock); + if (tfom->mss) + *mss = tfom->mss; + *cookie = tfom->cookie; + } while (read_seqretry(&fastopen_seqlock, seq)); + } + rcu_read_unlock(); +} + + +void tcp_fastopen_cache_set(struct sock *sk, u16 mss, + struct tcp_fastopen_cookie *cookie) +{ + struct tcp_metrics_block *tm; + + rcu_read_lock(); + tm = tcp_get_metrics(sk, __sk_dst_get(sk), true); + if (tm) { + struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; + + write_seqlock_bh(&fastopen_seqlock); + tfom->mss = mss; + if (cookie->len > 0) + tfom->cookie = *cookie; + write_sequnlock_bh(&fastopen_seqlock); + } + rcu_read_unlock(); +} + static unsigned long tcpmhash_entries; static int __init set_tcpmhash_entries(char *str) { -- cgit v1.2.3 From aab4874355679c70f93993cf3b3fd74643b9ac33 Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Thu, 19 Jul 2012 06:43:10 +0000 Subject: net-tcp: Fast Open client - detecting SYN-data drops On paths with firewalls dropping SYN with data or experimental TCP options, Fast Open connections will have experience SYN timeout and bad performance. The solution is to track such incidents in the cookie cache and disables Fast Open temporarily. Since only the original SYN includes data and/or Fast Open option, the SYN-ACK has some tell-tale sign (tcp_rcv_fastopen_synack()) to detect such drops. If a path has recurring Fast Open SYN drops, Fast Open is disabled for 2^(recurring_losses) minutes starting from four minutes up to roughly one and half day. sendmsg with MSG_FASTOPEN flag will succeed but it behaves as connect() then write(). Signed-off-by: Yuchung Cheng Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_metrics.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'net/ipv4/tcp_metrics.c') diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index d02ff3777785..99779ae44f64 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -32,6 +32,8 @@ enum tcp_metric_index { struct tcp_fastopen_metrics { u16 mss; + u16 syn_loss:10; /* Recurring Fast Open SYN losses */ + unsigned long last_syn_loss; /* Last Fast Open SYN loss */ struct tcp_fastopen_cookie cookie; }; @@ -125,6 +127,7 @@ static void tcpm_suck_dst(struct tcp_metrics_block *tm, struct dst_entry *dst) tm->tcpm_ts = 0; tm->tcpm_ts_stamp = 0; tm->tcpm_fastopen.mss = 0; + tm->tcpm_fastopen.syn_loss = 0; tm->tcpm_fastopen.cookie.len = 0; } @@ -644,7 +647,8 @@ bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw) static DEFINE_SEQLOCK(fastopen_seqlock); void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, - struct tcp_fastopen_cookie *cookie) + struct tcp_fastopen_cookie *cookie, + int *syn_loss, unsigned long *last_syn_loss) { struct tcp_metrics_block *tm; @@ -659,14 +663,15 @@ void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, if (tfom->mss) *mss = tfom->mss; *cookie = tfom->cookie; + *syn_loss = tfom->syn_loss; + *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0; } while (read_seqretry(&fastopen_seqlock, seq)); } rcu_read_unlock(); } - void tcp_fastopen_cache_set(struct sock *sk, u16 mss, - struct tcp_fastopen_cookie *cookie) + struct tcp_fastopen_cookie *cookie, bool syn_lost) { struct tcp_metrics_block *tm; @@ -679,6 +684,11 @@ void tcp_fastopen_cache_set(struct sock *sk, u16 mss, tfom->mss = mss; if (cookie->len > 0) tfom->cookie = *cookie; + if (syn_lost) { + ++tfom->syn_loss; + tfom->last_syn_loss = jiffies; + } else + tfom->syn_loss = 0; write_sequnlock_bh(&fastopen_seqlock); } rcu_read_unlock(); -- cgit v1.2.3 From 5815d5e7aae3cc9c5e85af83094d4d6498c3f4fc Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 19 Jul 2012 23:02:34 +0000 Subject: tcp: use hash_32() in tcp_metrics Fix a missing roundup_pow_of_two(), since tcpmhash_entries is not guaranteed to be a power of two. Uses hash_32() instead of custom hash. tcpmhash_entries should be an unsigned int. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_metrics.c | 25 ++++++++++--------------- 1 file changed, 10 insertions(+), 15 deletions(-) (limited to 'net/ipv4/tcp_metrics.c') diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 99779ae44f64..992f1bff4fc6 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include @@ -228,10 +229,8 @@ static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req, return NULL; } - hash ^= (hash >> 24) ^ (hash >> 16) ^ (hash >> 8); - net = dev_net(dst->dev); - hash &= net->ipv4.tcp_metrics_hash_mask; + hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; tm = rcu_dereference(tm->tcpm_next)) { @@ -265,10 +264,8 @@ static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock return NULL; } - hash ^= (hash >> 24) ^ (hash >> 16) ^ (hash >> 8); - net = twsk_net(tw); - hash &= net->ipv4.tcp_metrics_hash_mask; + hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm; tm = rcu_dereference(tm->tcpm_next)) { @@ -302,10 +299,8 @@ static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk, return NULL; } - hash ^= (hash >> 24) ^ (hash >> 16) ^ (hash >> 8); - net = dev_net(dst->dev); - hash &= net->ipv4.tcp_metrics_hash_mask; + hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); tm = __tcp_get_metrics(&addr, net, hash); reclaim = false; @@ -694,7 +689,7 @@ void tcp_fastopen_cache_set(struct sock *sk, u16 mss, rcu_read_unlock(); } -static unsigned long tcpmhash_entries; +static unsigned int tcpmhash_entries; static int __init set_tcpmhash_entries(char *str) { ssize_t ret; @@ -702,7 +697,7 @@ static int __init set_tcpmhash_entries(char *str) if (!str) return 0; - ret = kstrtoul(str, 0, &tcpmhash_entries); + ret = kstrtouint(str, 0, &tcpmhash_entries); if (ret) return 0; @@ -712,7 +707,8 @@ __setup("tcpmhash_entries=", set_tcpmhash_entries); static int __net_init tcp_net_metrics_init(struct net *net) { - int slots, size; + size_t size; + unsigned int slots; slots = tcpmhash_entries; if (!slots) { @@ -722,14 +718,13 @@ static int __net_init tcp_net_metrics_init(struct net *net) slots = 8 * 1024; } - size = slots * sizeof(struct tcpm_hash_bucket); + net->ipv4.tcp_metrics_hash_log = order_base_2(slots); + size = sizeof(struct tcpm_hash_bucket) << net->ipv4.tcp_metrics_hash_log; net->ipv4.tcp_metrics_hash = kzalloc(size, GFP_KERNEL); if (!net->ipv4.tcp_metrics_hash) return -ENOMEM; - net->ipv4.tcp_metrics_hash_mask = (slots - 1); - return 0; } -- cgit v1.2.3 From 9a0a9502cbf19d31f7387e3066f3d1a491bef616 Mon Sep 17 00:00:00 2001 From: Julian Anastasov Date: Mon, 23 Jul 2012 10:46:38 +0300 Subject: tcp: avoid oops in tcp_metrics and reset tcpm_stamp In tcp_tw_remember_stamp we incorrectly checked tw instead of tm, it can lead to oops if the cached entry is not found. tcpm_stamp was not updated in tcpm_check_stamp when tcpm_suck_dst was called, move the update into tcpm_suck_dst, so that we do not call it infinitely on every next cache hit after TCP_METRICS_TIMEOUT. Signed-off-by: Julian Anastasov Signed-off-by: David S. Miller --- net/ipv4/tcp_metrics.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'net/ipv4/tcp_metrics.c') diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 992f1bff4fc6..2288a6399e1e 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -107,6 +107,8 @@ static void tcpm_suck_dst(struct tcp_metrics_block *tm, struct dst_entry *dst) { u32 val; + tm->tcpm_stamp = jiffies; + val = 0; if (dst_metric_locked(dst, RTAX_RTT)) val |= 1 << TCP_METRIC_RTT; @@ -158,7 +160,6 @@ static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, goto out_unlock; } tm->tcpm_addr = *addr; - tm->tcpm_stamp = jiffies; tcpm_suck_dst(tm, dst); @@ -621,7 +622,7 @@ bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw) rcu_read_lock(); tm = __tcp_get_metrics_tw(tw); - if (tw) { + if (tm) { const struct tcp_timewait_sock *tcptw; struct sock *sk = (struct sock *) tw; -- cgit v1.2.3