diff options
Diffstat (limited to 'net/ipv4/tcp_metrics.c')
| -rw-r--r-- | net/ipv4/tcp_metrics.c | 745 |
1 files changed, 745 insertions, 0 deletions
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c new file mode 100644 index 00000000000..2288a6399e1 --- /dev/null +++ b/net/ipv4/tcp_metrics.c @@ -0,0 +1,745 @@ +#include <linux/rcupdate.h> +#include <linux/spinlock.h> +#include <linux/jiffies.h> +#include <linux/bootmem.h> +#include <linux/module.h> +#include <linux/cache.h> +#include <linux/slab.h> +#include <linux/init.h> +#include <linux/tcp.h> +#include <linux/hash.h> + +#include <net/inet_connection_sock.h> +#include <net/net_namespace.h> +#include <net/request_sock.h> +#include <net/inetpeer.h> +#include <net/sock.h> +#include <net/ipv6.h> +#include <net/dst.h> +#include <net/tcp.h> + +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_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; +}; + +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]; + struct tcp_fastopen_metrics tcpm_fastopen; +}; + +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; + + tm->tcpm_stamp = jiffies; + + 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); + 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; +} + +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; + + 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 = ipv6_addr_hash(&inet6_rsk(req)->rmt_addr); + break; + default: + return NULL; + } + + net = dev_net(dst->dev); + 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)) { + if (addr_same(&tm->tcpm_addr, &addr)) + break; + } + tcpm_check_stamp(tm, dst); + 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 = ipv6_addr_hash(&tw6->tw_v6_daddr); + break; + default: + return NULL; + } + + net = twsk_net(tw); + 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)) { + 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) +{ + 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 = ipv6_addr_hash(&inet6_sk(sk)->daddr); + break; + default: + return NULL; + } + + net = dev_net(dst->dev); + hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log); + + 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) +{ + 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 || !dst) + return; + + if (dst->flags & DST_HOST) + dst_confirm(dst); + + 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); + + if (!tm) + goto out_unlock; + + rtt = tcp_metric_get_jiffies(tm, TCP_METRIC_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 (!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); + } + + if (!tcp_metric_locked(tm, TCP_METRIC_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 = tcp_metric_get_jiffies(tm, TCP_METRIC_RTTVAR); + if (m >= var) + var = m; + else + var -= (var - m) >> 2; + + 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, TCP_METRIC_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) + 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 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); + + 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 { + /* ssthresh may have been reduced unnecessarily during. + * 3WHS. Restore it back to its initial default. + */ + tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; + } + val = tcp_metric_get(tm, TCP_METRIC_REORDERING); + if (val && tp->reordering != val) { + tcp_disable_fack(tp); + tcp_disable_early_retrans(tp); + tp->reordering = val; + } + + 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 + * 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. + */ + val = msecs_to_jiffies(val); + if (val > tp->srtt) { + tp->srtt = val; + tp->rtt_seq = tp->snd_nxt; + } + 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) { + /* 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; +} + +bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, bool paws_check) +{ + struct tcp_metrics_block *tm; + bool ret; + + if (!dst) + return false; + + rcu_read_lock(); + tm = __tcp_get_metrics_req(req, dst); + 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 (tm) { + 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 DEFINE_SEQLOCK(fastopen_seqlock); + +void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, + struct tcp_fastopen_cookie *cookie, + int *syn_loss, unsigned long *last_syn_loss) +{ + 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; + *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, bool syn_lost) +{ + 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; + if (syn_lost) { + ++tfom->syn_loss; + tfom->last_syn_loss = jiffies; + } else + tfom->syn_loss = 0; + write_sequnlock_bh(&fastopen_seqlock); + } + rcu_read_unlock(); +} + +static unsigned int tcpmhash_entries; +static int __init set_tcpmhash_entries(char *str) +{ + ssize_t ret; + + if (!str) + return 0; + + ret = kstrtouint(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) +{ + size_t size; + unsigned int slots; + + slots = tcpmhash_entries; + if (!slots) { + if (totalram_pages >= 128 * 1024) + slots = 16 * 1024; + else + slots = 8 * 1024; + } + + 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; + + 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); +} |