#include <linux/rcupdate.h> #include <linux/spinlock.h> #include <linux/jiffies.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 <linux/tcp_metrics.h> #include <linux/vmalloc.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> #include <net/genetlink.h> int sysctl_tcp_nometrics_save __read_mostly; static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *saddr, const struct inetpeer_addr *daddr, struct net *net, unsigned int hash); struct tcp_fastopen_metrics { u16 mss; u16 syn_loss:10, /* Recurring Fast Open SYN losses */ try_exp:2; /* Request w/ exp. option (once) */ unsigned long last_syn_loss; /* Last Fast Open SYN loss */ struct tcp_fastopen_cookie cookie; }; /* TCP_METRIC_MAX includes 2 extra fields for userspace compatibility * Kernel only stores RTT and RTTVAR in usec resolution */ #define TCP_METRIC_MAX_KERNEL (TCP_METRIC_MAX - 2) struct tcp_metrics_block { struct tcp_metrics_block __rcu *tcpm_next; possible_net_t tcpm_net; struct inetpeer_addr tcpm_saddr; struct inetpeer_addr tcpm_daddr; unsigned long tcpm_stamp; u32 tcpm_ts; u32 tcpm_ts_stamp; u32 tcpm_lock; u32 tcpm_vals[TCP_METRIC_MAX_KERNEL + 1]; struct tcp_fastopen_metrics tcpm_fastopen; struct rcu_head rcu_head; }; static inline struct net *tm_net(struct tcp_metrics_block *tm) { return read_pnet(&tm->tcpm_net); } 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 void tcp_metric_set(struct tcp_metrics_block *tm, enum tcp_metric_index idx, u32 val) { tm->tcpm_vals[idx] = val; } static bool addr_same(const struct inetpeer_addr *a, const struct inetpeer_addr *b) { return inetpeer_addr_cmp(a, b) == 0; } struct tcpm_hash_bucket { struct tcp_metrics_block __rcu *chain; }; static struct tcpm_hash_bucket *tcp_metrics_hash __read_mostly; static unsigned int tcp_metrics_hash_log __read_mostly; static DEFINE_SPINLOCK(tcp_metrics_lock); static void tcpm_suck_dst(struct tcp_metrics_block *tm, const struct dst_entry *dst, bool fastopen_clear) { u32 msval; 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; msval = dst_metric_raw(dst, RTAX_RTT); tm->tcpm_vals[TCP_METRIC_RTT] = msval * USEC_PER_MSEC; msval = dst_metric_raw(dst, RTAX_RTTVAR); tm->tcpm_vals[TCP_METRIC_RTTVAR] = msval * USEC_PER_MSEC; 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; if (fastopen_clear) { tm->tcpm_fastopen.mss = 0; tm->tcpm_fastopen.syn_loss = 0; tm->tcpm_fastopen.try_exp = 0; tm->tcpm_fastopen.cookie.exp = false; tm->tcpm_fastopen.cookie.len = 0; } } #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, false); } #define TCP_METRICS_RECLAIM_DEPTH 5 #define TCP_METRICS_RECLAIM_PTR (struct tcp_metrics_block *) 0x1UL #define deref_locked(p) \ rcu_dereference_protected(p, lockdep_is_held(&tcp_metrics_lock)) static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst, struct inetpeer_addr *saddr, struct inetpeer_addr *daddr, unsigned int hash) { struct tcp_metrics_block *tm; struct net *net; bool reclaim = false; spin_lock_bh(&tcp_metrics_lock); net = dev_net(dst->dev); /* While waiting for the spin-lock the cache might have been populated * with this entry and so we have to check again. */ tm = __tcp_get_metrics(saddr, daddr, net, hash); if (tm == TCP_METRICS_RECLAIM_PTR) { reclaim = true; tm = NULL; } if (tm) { tcpm_check_stamp(tm, dst); goto out_unlock; } if (unlikely(reclaim)) { struct tcp_metrics_block *oldest; oldest = deref_locked(tcp_metrics_hash[hash].chain); for (tm = deref_locked(oldest->tcpm_next); tm; tm = deref_locked(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; } write_pnet(&tm->tcpm_net, net); tm->tcpm_saddr = *saddr; tm->tcpm_daddr = *daddr; tcpm_suck_dst(tm, dst, true); if (likely(!reclaim)) { tm->tcpm_next = tcp_metrics_hash[hash].chain; rcu_assign_pointer(tcp_metrics_hash[hash].chain, tm); } out_unlock: spin_unlock_bh(&tcp_metrics_lock); return tm; } 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 *saddr, const struct inetpeer_addr *daddr, struct net *net, unsigned int hash) { struct tcp_metrics_block *tm; int depth = 0; for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; tm = rcu_dereference(tm->tcpm_next)) { if (addr_same(&tm->tcpm_saddr, saddr) && addr_same(&tm->tcpm_daddr, daddr) && net_eq(tm_net(tm), net)) 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 saddr, daddr; unsigned int hash; struct net *net; saddr.family = req->rsk_ops->family; daddr.family = req->rsk_ops->family; switch (daddr.family) { case AF_INET: inetpeer_set_addr_v4(&saddr, inet_rsk(req)->ir_loc_addr); inetpeer_set_addr_v4(&daddr, inet_rsk(req)->ir_rmt_addr); hash = ipv4_addr_hash(inet_rsk(req)->ir_rmt_addr); break; #if IS_ENABLED(CONFIG_IPV6) case AF_INET6: inetpeer_set_addr_v6(&saddr, &inet_rsk(req)->ir_v6_loc_addr); inetpeer_set_addr_v6(&daddr, &inet_rsk(req)->ir_v6_rmt_addr); hash = ipv6_addr_hash(&inet_rsk(req)->ir_v6_rmt_addr); break; #endif default: return NULL; } net = dev_net(dst->dev); hash ^= net_hash_mix(net); hash = hash_32(hash, tcp_metrics_hash_log); for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; tm = rcu_dereference(tm->tcpm_next)) { if (addr_same(&tm->tcpm_saddr, &saddr) && addr_same(&tm->tcpm_daddr, &daddr) && net_eq(tm_net(tm), net)) break; } tcpm_check_stamp(tm, dst); return tm; } static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock *tw) { struct tcp_metrics_block *tm; struct inetpeer_addr saddr, daddr; unsigned int hash; struct net *net; if (tw->tw_family == AF_INET) { inetpeer_set_addr_v4(&saddr, tw->tw_rcv_saddr); inetpeer_set_addr_v4(&daddr, tw->tw_daddr); hash = ipv4_addr_hash(tw->tw_daddr); } #if IS_ENABLED(CONFIG_IPV6) else if (tw->tw_family == AF_INET6) { if (ipv6_addr_v4mapped(&tw->tw_v6_daddr)) { inetpeer_set_addr_v4(&saddr, tw->tw_rcv_saddr); inetpeer_set_addr_v4(&daddr, tw->tw_daddr); hash = ipv4_addr_hash(tw->tw_daddr); } else { inetpeer_set_addr_v6(&saddr, &tw->tw_v6_rcv_saddr); inetpeer_set_addr_v6(&daddr, &tw->tw_v6_daddr); hash = ipv6_addr_hash(&tw->tw_v6_daddr); } } #endif else return NULL; net = twsk_net(tw); hash ^= net_hash_mix(net); hash = hash_32(hash, tcp_metrics_hash_log); for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; tm = rcu_dereference(tm->tcpm_next)) { if (addr_same(&tm->tcpm_saddr, &saddr) && addr_same(&tm->tcpm_daddr, &daddr) && net_eq(tm_net(tm), net)) 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 saddr, daddr; unsigned int hash; struct net *net; if (sk->sk_family == AF_INET) { inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr); inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr); hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr); } #if IS_ENABLED(CONFIG_IPV6) else if (sk->sk_family == AF_INET6) { if (ipv6_addr_v4mapped(&sk->sk_v6_daddr)) { inetpeer_set_addr_v4(&saddr, inet_sk(sk)->inet_saddr); inetpeer_set_addr_v4(&daddr, inet_sk(sk)->inet_daddr); hash = ipv4_addr_hash(inet_sk(sk)->inet_daddr); } else { inetpeer_set_addr_v6(&saddr, &sk->sk_v6_rcv_saddr); inetpeer_set_addr_v6(&daddr, &sk->sk_v6_daddr); hash = ipv6_addr_hash(&sk->sk_v6_daddr); } } #endif else return NULL; net = dev_net(dst->dev); hash ^= net_hash_mix(net); hash = hash_32(hash, tcp_metrics_hash_log); tm = __tcp_get_metrics(&saddr, &daddr, net, hash); if (tm == TCP_METRICS_RECLAIM_PTR) tm = NULL; if (!tm && create) tm = tcpm_new(dst, &saddr, &daddr, hash); 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_us) { /* 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(tm, TCP_METRIC_RTT); m = rtt - tp->srtt_us; /* 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_us; else rtt -= (m >> 3); tcp_metric_set(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_us) m = tp->mdev_us; var = tcp_metric_get(tm, TCP_METRIC_RTTVAR); if (m >= var) var = m; else var -= (var - m) >> 2; tcp_metric_set(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 (!tcp_in_slow_start(tp) && 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, crtt = 0; /* cached RTT scaled by 8 */ if (!dst) 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; } crtt = tcp_metric_get(tm, TCP_METRIC_RTT); rcu_read_unlock(); reset: /* The initial RTT measurement from the SYN/SYN-ACK is not ideal * to seed the RTO for later data packets because SYN packets are * small. Use the per-dst cached values to seed the RTO but keep * the RTT estimator variables intact (e.g., srtt, mdev, rttvar). * Later the RTO will be updated immediately upon obtaining the first * data RTT sample (tcp_rtt_estimator()). Hence the cached RTT only * influences the first RTO but not later RTT estimation. * * But if RTT is not available from the SYN (due to retransmits or * syn cookies) or the cache, force a conservative 3secs timeout. * * 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 (crtt > tp->srtt_us) { /* Set RTO like tcp_rtt_estimator(), but from cached RTT. */ crtt /= 8 * USEC_PER_SEC / HZ; inet_csk(sk)->icsk_rto = crtt + max(2 * crtt, tcp_rto_min(sk)); } else if (tp->srtt_us == 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->rttvar_us = jiffies_to_usecs(TCP_TIMEOUT_FALLBACK); tp->mdev_us = tp->mdev_max_us = tp->rttvar_us; 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, bool timestamps) { 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 || !timestamps)) 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; if (cookie->len <= 0 && tfom->try_exp == 1) cookie->exp = true; *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, u16 try_exp) { struct dst_entry *dst = __sk_dst_get(sk); struct tcp_metrics_block *tm; if (!dst) return; rcu_read_lock(); tm = tcp_get_metrics(sk, dst, true); if (tm) { struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; write_seqlock_bh(&fastopen_seqlock); if (mss) tfom->mss = mss; if (cookie && cookie->len > 0) tfom->cookie = *cookie; else if (try_exp > tfom->try_exp && tfom->cookie.len <= 0 && !tfom->cookie.exp) tfom->try_exp = try_exp; 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 struct genl_family tcp_metrics_nl_family = { .id = GENL_ID_GENERATE, .hdrsize = 0, .name = TCP_METRICS_GENL_NAME, .version = TCP_METRICS_GENL_VERSION, .maxattr = TCP_METRICS_ATTR_MAX, .netnsok = true, }; static struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = { [TCP_METRICS_ATTR_ADDR_IPV4] = { .type = NLA_U32, }, [TCP_METRICS_ATTR_ADDR_IPV6] = { .type = NLA_BINARY, .len = sizeof(struct in6_addr), }, /* Following attributes are not received for GET/DEL, * we keep them for reference */ #if 0 [TCP_METRICS_ATTR_AGE] = { .type = NLA_MSECS, }, [TCP_METRICS_ATTR_TW_TSVAL] = { .type = NLA_U32, }, [TCP_METRICS_ATTR_TW_TS_STAMP] = { .type = NLA_S32, }, [TCP_METRICS_ATTR_VALS] = { .type = NLA_NESTED, }, [TCP_METRICS_ATTR_FOPEN_MSS] = { .type = NLA_U16, }, [TCP_METRICS_ATTR_FOPEN_SYN_DROPS] = { .type = NLA_U16, }, [TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS] = { .type = NLA_MSECS, }, [TCP_METRICS_ATTR_FOPEN_COOKIE] = { .type = NLA_BINARY, .len = TCP_FASTOPEN_COOKIE_MAX, }, #endif }; /* Add attributes, caller cancels its header on failure */ static int tcp_metrics_fill_info(struct sk_buff *msg, struct tcp_metrics_block *tm) { struct nlattr *nest; int i; switch (tm->tcpm_daddr.family) { case AF_INET: if (nla_put_in_addr(msg, TCP_METRICS_ATTR_ADDR_IPV4, inetpeer_get_addr_v4(&tm->tcpm_daddr)) < 0) goto nla_put_failure; if (nla_put_in_addr(msg, TCP_METRICS_ATTR_SADDR_IPV4, inetpeer_get_addr_v4(&tm->tcpm_saddr)) < 0) goto nla_put_failure; break; case AF_INET6: if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_ADDR_IPV6, inetpeer_get_addr_v6(&tm->tcpm_daddr)) < 0) goto nla_put_failure; if (nla_put_in6_addr(msg, TCP_METRICS_ATTR_SADDR_IPV6, inetpeer_get_addr_v6(&tm->tcpm_saddr)) < 0) goto nla_put_failure; break; default: return -EAFNOSUPPORT; } if (nla_put_msecs(msg, TCP_METRICS_ATTR_AGE, jiffies - tm->tcpm_stamp) < 0) goto nla_put_failure; if (tm->tcpm_ts_stamp) { if (nla_put_s32(msg, TCP_METRICS_ATTR_TW_TS_STAMP, (s32) (get_seconds() - tm->tcpm_ts_stamp)) < 0) goto nla_put_failure; if (nla_put_u32(msg, TCP_METRICS_ATTR_TW_TSVAL, tm->tcpm_ts) < 0) goto nla_put_failure; } { int n = 0; nest = nla_nest_start(msg, TCP_METRICS_ATTR_VALS); if (!nest) goto nla_put_failure; for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) { u32 val = tm->tcpm_vals[i]; if (!val) continue; if (i == TCP_METRIC_RTT) { if (nla_put_u32(msg, TCP_METRIC_RTT_US + 1, val) < 0) goto nla_put_failure; n++; val = max(val / 1000, 1U); } if (i == TCP_METRIC_RTTVAR) { if (nla_put_u32(msg, TCP_METRIC_RTTVAR_US + 1, val) < 0) goto nla_put_failure; n++; val = max(val / 1000, 1U); } if (nla_put_u32(msg, i + 1, val) < 0) goto nla_put_failure; n++; } if (n) nla_nest_end(msg, nest); else nla_nest_cancel(msg, nest); } { struct tcp_fastopen_metrics tfom_copy[1], *tfom; unsigned int seq; do { seq = read_seqbegin(&fastopen_seqlock); tfom_copy[0] = tm->tcpm_fastopen; } while (read_seqretry(&fastopen_seqlock, seq)); tfom = tfom_copy; if (tfom->mss && nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_MSS, tfom->mss) < 0) goto nla_put_failure; if (tfom->syn_loss && (nla_put_u16(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROPS, tfom->syn_loss) < 0 || nla_put_msecs(msg, TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS, jiffies - tfom->last_syn_loss) < 0)) goto nla_put_failure; if (tfom->cookie.len > 0 && nla_put(msg, TCP_METRICS_ATTR_FOPEN_COOKIE, tfom->cookie.len, tfom->cookie.val) < 0) goto nla_put_failure; } return 0; nla_put_failure: return -EMSGSIZE; } static int tcp_metrics_dump_info(struct sk_buff *skb, struct netlink_callback *cb, struct tcp_metrics_block *tm) { void *hdr; hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, &tcp_metrics_nl_family, NLM_F_MULTI, TCP_METRICS_CMD_GET); if (!hdr) return -EMSGSIZE; if (tcp_metrics_fill_info(skb, tm) < 0) goto nla_put_failure; genlmsg_end(skb, hdr); return 0; nla_put_failure: genlmsg_cancel(skb, hdr); return -EMSGSIZE; } static int tcp_metrics_nl_dump(struct sk_buff *skb, struct netlink_callback *cb) { struct net *net = sock_net(skb->sk); unsigned int max_rows = 1U << tcp_metrics_hash_log; unsigned int row, s_row = cb->args[0]; int s_col = cb->args[1], col = s_col; for (row = s_row; row < max_rows; row++, s_col = 0) { struct tcp_metrics_block *tm; struct tcpm_hash_bucket *hb = tcp_metrics_hash + row; rcu_read_lock(); for (col = 0, tm = rcu_dereference(hb->chain); tm; tm = rcu_dereference(tm->tcpm_next), col++) { if (!net_eq(tm_net(tm), net)) continue; if (col < s_col) continue; if (tcp_metrics_dump_info(skb, cb, tm) < 0) { rcu_read_unlock(); goto done; } } rcu_read_unlock(); } done: cb->args[0] = row; cb->args[1] = col; return skb->len; } static int __parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, unsigned int *hash, int optional, int v4, int v6) { struct nlattr *a; a = info->attrs[v4]; if (a) { inetpeer_set_addr_v4(addr, nla_get_in_addr(a)); if (hash) *hash = ipv4_addr_hash(inetpeer_get_addr_v4(addr)); return 0; } a = info->attrs[v6]; if (a) { struct in6_addr in6; if (nla_len(a) != sizeof(struct in6_addr)) return -EINVAL; in6 = nla_get_in6_addr(a); inetpeer_set_addr_v6(addr, &in6); if (hash) *hash = ipv6_addr_hash(inetpeer_get_addr_v6(addr)); return 0; } return optional ? 1 : -EAFNOSUPPORT; } static int parse_nl_addr(struct genl_info *info, struct inetpeer_addr *addr, unsigned int *hash, int optional) { return __parse_nl_addr(info, addr, hash, optional, TCP_METRICS_ATTR_ADDR_IPV4, TCP_METRICS_ATTR_ADDR_IPV6); } static int parse_nl_saddr(struct genl_info *info, struct inetpeer_addr *addr) { return __parse_nl_addr(info, addr, NULL, 0, TCP_METRICS_ATTR_SADDR_IPV4, TCP_METRICS_ATTR_SADDR_IPV6); } static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info) { struct tcp_metrics_block *tm; struct inetpeer_addr saddr, daddr; unsigned int hash; struct sk_buff *msg; struct net *net = genl_info_net(info); void *reply; int ret; bool src = true; ret = parse_nl_addr(info, &daddr, &hash, 0); if (ret < 0) return ret; ret = parse_nl_saddr(info, &saddr); if (ret < 0) src = false; msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); if (!msg) return -ENOMEM; reply = genlmsg_put_reply(msg, info, &tcp_metrics_nl_family, 0, info->genlhdr->cmd); if (!reply) goto nla_put_failure; hash ^= net_hash_mix(net); hash = hash_32(hash, tcp_metrics_hash_log); ret = -ESRCH; rcu_read_lock(); for (tm = rcu_dereference(tcp_metrics_hash[hash].chain); tm; tm = rcu_dereference(tm->tcpm_next)) { if (addr_same(&tm->tcpm_daddr, &daddr) && (!src || addr_same(&tm->tcpm_saddr, &saddr)) && net_eq(tm_net(tm), net)) { ret = tcp_metrics_fill_info(msg, tm); break; } } rcu_read_unlock(); if (ret < 0) goto out_free; genlmsg_end(msg, reply); return genlmsg_reply(msg, info); nla_put_failure: ret = -EMSGSIZE; out_free: nlmsg_free(msg); return ret; } static void tcp_metrics_flush_all(struct net *net) { unsigned int max_rows = 1U << tcp_metrics_hash_log; struct tcpm_hash_bucket *hb = tcp_metrics_hash; struct tcp_metrics_block *tm; unsigned int row; for (row = 0; row < max_rows; row++, hb++) { struct tcp_metrics_block __rcu **pp; spin_lock_bh(&tcp_metrics_lock); pp = &hb->chain; for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { if (net_eq(tm_net(tm), net)) { *pp = tm->tcpm_next; kfree_rcu(tm, rcu_head); } else { pp = &tm->tcpm_next; } } spin_unlock_bh(&tcp_metrics_lock); } } static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info) { struct tcpm_hash_bucket *hb; struct tcp_metrics_block *tm; struct tcp_metrics_block __rcu **pp; struct inetpeer_addr saddr, daddr; unsigned int hash; struct net *net = genl_info_net(info); int ret; bool src = true, found = false; ret = parse_nl_addr(info, &daddr, &hash, 1); if (ret < 0) return ret; if (ret > 0) { tcp_metrics_flush_all(net); return 0; } ret = parse_nl_saddr(info, &saddr); if (ret < 0) src = false; hash ^= net_hash_mix(net); hash = hash_32(hash, tcp_metrics_hash_log); hb = tcp_metrics_hash + hash; pp = &hb->chain; spin_lock_bh(&tcp_metrics_lock); for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) { if (addr_same(&tm->tcpm_daddr, &daddr) && (!src || addr_same(&tm->tcpm_saddr, &saddr)) && net_eq(tm_net(tm), net)) { *pp = tm->tcpm_next; kfree_rcu(tm, rcu_head); found = true; } else { pp = &tm->tcpm_next; } } spin_unlock_bh(&tcp_metrics_lock); if (!found) return -ESRCH; return 0; } static const struct genl_ops tcp_metrics_nl_ops[] = { { .cmd = TCP_METRICS_CMD_GET, .doit = tcp_metrics_nl_cmd_get, .dumpit = tcp_metrics_nl_dump, .policy = tcp_metrics_nl_policy, }, { .cmd = TCP_METRICS_CMD_DEL, .doit = tcp_metrics_nl_cmd_del, .policy = tcp_metrics_nl_policy, .flags = GENL_ADMIN_PERM, }, }; 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; if (!net_eq(net, &init_net)) return 0; slots = tcpmhash_entries; if (!slots) { if (totalram_pages >= 128 * 1024) slots = 16 * 1024; else slots = 8 * 1024; } tcp_metrics_hash_log = order_base_2(slots); size = sizeof(struct tcpm_hash_bucket) << tcp_metrics_hash_log; tcp_metrics_hash = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); if (!tcp_metrics_hash) tcp_metrics_hash = vzalloc(size); if (!tcp_metrics_hash) return -ENOMEM; return 0; } static void __net_exit tcp_net_metrics_exit(struct net *net) { tcp_metrics_flush_all(net); } 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) { int ret; ret = register_pernet_subsys(&tcp_net_metrics_ops); if (ret < 0) panic("Could not allocate the tcp_metrics hash table\n"); ret = genl_register_family_with_ops(&tcp_metrics_nl_family, tcp_metrics_nl_ops); if (ret < 0) panic("Could not register tcp_metrics generic netlink\n"); }