v4.19.13 snapshot.
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
new file mode 100644
index 0000000..03b51cd
--- /dev/null
+++ b/net/ipv4/tcp_metrics.c
@@ -0,0 +1,1040 @@
+// SPDX-License-Identifier: GPL-2.0
+#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>
+
+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_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);
+ 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(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 net *net = sock_net(sk);
+ struct tcp_metrics_block *tm;
+ unsigned long rtt;
+ u32 val;
+ int m;
+
+ sk_dst_confirm(sk);
+ if (net->ipv4.sysctl_tcp_nometrics_save || !dst)
+ return;
+
+ 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 != net->ipv4.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 */
+
+ sk_dst_confirm(sk);
+ if (!dst)
+ goto reset;
+
+ 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)
+ 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_jiffies32;
+}
+
+bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst)
+{
+ struct tcp_metrics_block *tm;
+ bool ret;
+
+ if (!dst)
+ return 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;
+}
+
+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;
+ if (cookie->len <= 0 && tfom->try_exp == 1)
+ cookie->exp = true;
+ } 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;
+
+static const 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,
+ TCP_METRICS_ATTR_PAD) < 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,
+ TCP_METRICS_ATTR_PAD) < 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;
+ bool match;
+
+ spin_lock_bh(&tcp_metrics_lock);
+ pp = &hb->chain;
+ for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) {
+ match = net ? net_eq(tm_net(tm), net) :
+ !refcount_read(&tm_net(tm)->count);
+ if (match) {
+ *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 struct genl_family tcp_metrics_nl_family __ro_after_init = {
+ .hdrsize = 0,
+ .name = TCP_METRICS_GENL_NAME,
+ .version = TCP_METRICS_GENL_VERSION,
+ .maxattr = TCP_METRICS_ATTR_MAX,
+ .netnsok = true,
+ .module = THIS_MODULE,
+ .ops = tcp_metrics_nl_ops,
+ .n_ops = ARRAY_SIZE(tcp_metrics_nl_ops),
+};
+
+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 = kvzalloc(size, GFP_KERNEL);
+ if (!tcp_metrics_hash)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void __net_exit tcp_net_metrics_exit_batch(struct list_head *net_exit_list)
+{
+ tcp_metrics_flush_all(NULL);
+}
+
+static __net_initdata struct pernet_operations tcp_net_metrics_ops = {
+ .init = tcp_net_metrics_init,
+ .exit_batch = tcp_net_metrics_exit_batch,
+};
+
+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(&tcp_metrics_nl_family);
+ if (ret < 0)
+ panic("Could not register tcp_metrics generic netlink\n");
+}