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Diffstat (limited to 'kernel/net/ipv4/inet_connection_sock.c')
-rw-r--r--kernel/net/ipv4/inet_connection_sock.c978
1 files changed, 978 insertions, 0 deletions
diff --git a/kernel/net/ipv4/inet_connection_sock.c b/kernel/net/ipv4/inet_connection_sock.c
new file mode 100644
index 000000000..8976ca423
--- /dev/null
+++ b/kernel/net/ipv4/inet_connection_sock.c
@@ -0,0 +1,978 @@
+/*
+ * INET An implementation of the TCP/IP protocol suite for the LINUX
+ * operating system. INET is implemented using the BSD Socket
+ * interface as the means of communication with the user level.
+ *
+ * Support for INET connection oriented protocols.
+ *
+ * Authors: See the TCP sources
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or(at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/jhash.h>
+
+#include <net/inet_connection_sock.h>
+#include <net/inet_hashtables.h>
+#include <net/inet_timewait_sock.h>
+#include <net/ip.h>
+#include <net/route.h>
+#include <net/tcp_states.h>
+#include <net/xfrm.h>
+#include <net/tcp.h>
+
+#ifdef INET_CSK_DEBUG
+const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
+EXPORT_SYMBOL(inet_csk_timer_bug_msg);
+#endif
+
+void inet_get_local_port_range(struct net *net, int *low, int *high)
+{
+ unsigned int seq;
+
+ do {
+ seq = read_seqbegin(&net->ipv4.ip_local_ports.lock);
+
+ *low = net->ipv4.ip_local_ports.range[0];
+ *high = net->ipv4.ip_local_ports.range[1];
+ } while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq));
+}
+EXPORT_SYMBOL(inet_get_local_port_range);
+
+int inet_csk_bind_conflict(const struct sock *sk,
+ const struct inet_bind_bucket *tb, bool relax)
+{
+ struct sock *sk2;
+ int reuse = sk->sk_reuse;
+ int reuseport = sk->sk_reuseport;
+ kuid_t uid = sock_i_uid((struct sock *)sk);
+
+ /*
+ * Unlike other sk lookup places we do not check
+ * for sk_net here, since _all_ the socks listed
+ * in tb->owners list belong to the same net - the
+ * one this bucket belongs to.
+ */
+
+ sk_for_each_bound(sk2, &tb->owners) {
+ if (sk != sk2 &&
+ !inet_v6_ipv6only(sk2) &&
+ (!sk->sk_bound_dev_if ||
+ !sk2->sk_bound_dev_if ||
+ sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
+ if ((!reuse || !sk2->sk_reuse ||
+ sk2->sk_state == TCP_LISTEN) &&
+ (!reuseport || !sk2->sk_reuseport ||
+ (sk2->sk_state != TCP_TIME_WAIT &&
+ !uid_eq(uid, sock_i_uid(sk2))))) {
+
+ if (!sk2->sk_rcv_saddr || !sk->sk_rcv_saddr ||
+ sk2->sk_rcv_saddr == sk->sk_rcv_saddr)
+ break;
+ }
+ if (!relax && reuse && sk2->sk_reuse &&
+ sk2->sk_state != TCP_LISTEN) {
+
+ if (!sk2->sk_rcv_saddr || !sk->sk_rcv_saddr ||
+ sk2->sk_rcv_saddr == sk->sk_rcv_saddr)
+ break;
+ }
+ }
+ }
+ return sk2 != NULL;
+}
+EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);
+
+/* Obtain a reference to a local port for the given sock,
+ * if snum is zero it means select any available local port.
+ */
+int inet_csk_get_port(struct sock *sk, unsigned short snum)
+{
+ struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
+ struct inet_bind_hashbucket *head;
+ struct inet_bind_bucket *tb;
+ int ret, attempts = 5;
+ struct net *net = sock_net(sk);
+ int smallest_size = -1, smallest_rover;
+ kuid_t uid = sock_i_uid(sk);
+
+ local_bh_disable();
+ if (!snum) {
+ int remaining, rover, low, high;
+
+again:
+ inet_get_local_port_range(net, &low, &high);
+ remaining = (high - low) + 1;
+ smallest_rover = rover = prandom_u32() % remaining + low;
+
+ smallest_size = -1;
+ do {
+ if (inet_is_local_reserved_port(net, rover))
+ goto next_nolock;
+ head = &hashinfo->bhash[inet_bhashfn(net, rover,
+ hashinfo->bhash_size)];
+ spin_lock(&head->lock);
+ inet_bind_bucket_for_each(tb, &head->chain)
+ if (net_eq(ib_net(tb), net) && tb->port == rover) {
+ if (((tb->fastreuse > 0 &&
+ sk->sk_reuse &&
+ sk->sk_state != TCP_LISTEN) ||
+ (tb->fastreuseport > 0 &&
+ sk->sk_reuseport &&
+ uid_eq(tb->fastuid, uid))) &&
+ (tb->num_owners < smallest_size || smallest_size == -1)) {
+ smallest_size = tb->num_owners;
+ smallest_rover = rover;
+ if (atomic_read(&hashinfo->bsockets) > (high - low) + 1 &&
+ !inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) {
+ snum = smallest_rover;
+ goto tb_found;
+ }
+ }
+ if (!inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) {
+ snum = rover;
+ goto tb_found;
+ }
+ goto next;
+ }
+ break;
+ next:
+ spin_unlock(&head->lock);
+ next_nolock:
+ if (++rover > high)
+ rover = low;
+ } while (--remaining > 0);
+
+ /* Exhausted local port range during search? It is not
+ * possible for us to be holding one of the bind hash
+ * locks if this test triggers, because if 'remaining'
+ * drops to zero, we broke out of the do/while loop at
+ * the top level, not from the 'break;' statement.
+ */
+ ret = 1;
+ if (remaining <= 0) {
+ if (smallest_size != -1) {
+ snum = smallest_rover;
+ goto have_snum;
+ }
+ goto fail;
+ }
+ /* OK, here is the one we will use. HEAD is
+ * non-NULL and we hold it's mutex.
+ */
+ snum = rover;
+ } else {
+have_snum:
+ head = &hashinfo->bhash[inet_bhashfn(net, snum,
+ hashinfo->bhash_size)];
+ spin_lock(&head->lock);
+ inet_bind_bucket_for_each(tb, &head->chain)
+ if (net_eq(ib_net(tb), net) && tb->port == snum)
+ goto tb_found;
+ }
+ tb = NULL;
+ goto tb_not_found;
+tb_found:
+ if (!hlist_empty(&tb->owners)) {
+ if (sk->sk_reuse == SK_FORCE_REUSE)
+ goto success;
+
+ if (((tb->fastreuse > 0 &&
+ sk->sk_reuse && sk->sk_state != TCP_LISTEN) ||
+ (tb->fastreuseport > 0 &&
+ sk->sk_reuseport && uid_eq(tb->fastuid, uid))) &&
+ smallest_size == -1) {
+ goto success;
+ } else {
+ ret = 1;
+ if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, true)) {
+ if (((sk->sk_reuse && sk->sk_state != TCP_LISTEN) ||
+ (tb->fastreuseport > 0 &&
+ sk->sk_reuseport && uid_eq(tb->fastuid, uid))) &&
+ smallest_size != -1 && --attempts >= 0) {
+ spin_unlock(&head->lock);
+ goto again;
+ }
+
+ goto fail_unlock;
+ }
+ }
+ }
+tb_not_found:
+ ret = 1;
+ if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep,
+ net, head, snum)) == NULL)
+ goto fail_unlock;
+ if (hlist_empty(&tb->owners)) {
+ if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
+ tb->fastreuse = 1;
+ else
+ tb->fastreuse = 0;
+ if (sk->sk_reuseport) {
+ tb->fastreuseport = 1;
+ tb->fastuid = uid;
+ } else
+ tb->fastreuseport = 0;
+ } else {
+ if (tb->fastreuse &&
+ (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
+ tb->fastreuse = 0;
+ if (tb->fastreuseport &&
+ (!sk->sk_reuseport || !uid_eq(tb->fastuid, uid)))
+ tb->fastreuseport = 0;
+ }
+success:
+ if (!inet_csk(sk)->icsk_bind_hash)
+ inet_bind_hash(sk, tb, snum);
+ WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
+ ret = 0;
+
+fail_unlock:
+ spin_unlock(&head->lock);
+fail:
+ local_bh_enable();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(inet_csk_get_port);
+
+/*
+ * Wait for an incoming connection, avoid race conditions. This must be called
+ * with the socket locked.
+ */
+static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ DEFINE_WAIT(wait);
+ int err;
+
+ /*
+ * True wake-one mechanism for incoming connections: only
+ * one process gets woken up, not the 'whole herd'.
+ * Since we do not 'race & poll' for established sockets
+ * anymore, the common case will execute the loop only once.
+ *
+ * Subtle issue: "add_wait_queue_exclusive()" will be added
+ * after any current non-exclusive waiters, and we know that
+ * it will always _stay_ after any new non-exclusive waiters
+ * because all non-exclusive waiters are added at the
+ * beginning of the wait-queue. As such, it's ok to "drop"
+ * our exclusiveness temporarily when we get woken up without
+ * having to remove and re-insert us on the wait queue.
+ */
+ for (;;) {
+ prepare_to_wait_exclusive(sk_sleep(sk), &wait,
+ TASK_INTERRUPTIBLE);
+ release_sock(sk);
+ if (reqsk_queue_empty(&icsk->icsk_accept_queue))
+ timeo = schedule_timeout(timeo);
+ sched_annotate_sleep();
+ lock_sock(sk);
+ err = 0;
+ if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
+ break;
+ err = -EINVAL;
+ if (sk->sk_state != TCP_LISTEN)
+ break;
+ err = sock_intr_errno(timeo);
+ if (signal_pending(current))
+ break;
+ err = -EAGAIN;
+ if (!timeo)
+ break;
+ }
+ finish_wait(sk_sleep(sk), &wait);
+ return err;
+}
+
+/*
+ * This will accept the next outstanding connection.
+ */
+struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct request_sock_queue *queue = &icsk->icsk_accept_queue;
+ struct request_sock *req;
+ struct sock *newsk;
+ int error;
+
+ lock_sock(sk);
+
+ /* We need to make sure that this socket is listening,
+ * and that it has something pending.
+ */
+ error = -EINVAL;
+ if (sk->sk_state != TCP_LISTEN)
+ goto out_err;
+
+ /* Find already established connection */
+ if (reqsk_queue_empty(queue)) {
+ long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
+
+ /* If this is a non blocking socket don't sleep */
+ error = -EAGAIN;
+ if (!timeo)
+ goto out_err;
+
+ error = inet_csk_wait_for_connect(sk, timeo);
+ if (error)
+ goto out_err;
+ }
+ req = reqsk_queue_remove(queue);
+ newsk = req->sk;
+
+ sk_acceptq_removed(sk);
+ if (sk->sk_protocol == IPPROTO_TCP &&
+ tcp_rsk(req)->tfo_listener &&
+ queue->fastopenq) {
+ spin_lock_bh(&queue->fastopenq->lock);
+ if (tcp_rsk(req)->tfo_listener) {
+ /* We are still waiting for the final ACK from 3WHS
+ * so can't free req now. Instead, we set req->sk to
+ * NULL to signify that the child socket is taken
+ * so reqsk_fastopen_remove() will free the req
+ * when 3WHS finishes (or is aborted).
+ */
+ req->sk = NULL;
+ req = NULL;
+ }
+ spin_unlock_bh(&queue->fastopenq->lock);
+ }
+out:
+ release_sock(sk);
+ if (req)
+ reqsk_put(req);
+ return newsk;
+out_err:
+ newsk = NULL;
+ req = NULL;
+ *err = error;
+ goto out;
+}
+EXPORT_SYMBOL(inet_csk_accept);
+
+/*
+ * Using different timers for retransmit, delayed acks and probes
+ * We may wish use just one timer maintaining a list of expire jiffies
+ * to optimize.
+ */
+void inet_csk_init_xmit_timers(struct sock *sk,
+ void (*retransmit_handler)(unsigned long),
+ void (*delack_handler)(unsigned long),
+ void (*keepalive_handler)(unsigned long))
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+
+ setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler,
+ (unsigned long)sk);
+ setup_timer(&icsk->icsk_delack_timer, delack_handler,
+ (unsigned long)sk);
+ setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk);
+ icsk->icsk_pending = icsk->icsk_ack.pending = 0;
+}
+EXPORT_SYMBOL(inet_csk_init_xmit_timers);
+
+void inet_csk_clear_xmit_timers(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+
+ icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
+
+ sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
+ sk_stop_timer(sk, &icsk->icsk_delack_timer);
+ sk_stop_timer(sk, &sk->sk_timer);
+}
+EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
+
+void inet_csk_delete_keepalive_timer(struct sock *sk)
+{
+ sk_stop_timer(sk, &sk->sk_timer);
+}
+EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
+
+void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
+{
+ sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
+}
+EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
+
+struct dst_entry *inet_csk_route_req(struct sock *sk,
+ struct flowi4 *fl4,
+ const struct request_sock *req)
+{
+ const struct inet_request_sock *ireq = inet_rsk(req);
+ struct net *net = read_pnet(&ireq->ireq_net);
+ struct ip_options_rcu *opt = ireq->opt;
+ struct rtable *rt;
+
+ flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
+ RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
+ sk->sk_protocol, inet_sk_flowi_flags(sk),
+ (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
+ ireq->ir_loc_addr, ireq->ir_rmt_port,
+ htons(ireq->ir_num));
+ security_req_classify_flow(req, flowi4_to_flowi(fl4));
+ rt = ip_route_output_flow(net, fl4, sk);
+ if (IS_ERR(rt))
+ goto no_route;
+ if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
+ goto route_err;
+ return &rt->dst;
+
+route_err:
+ ip_rt_put(rt);
+no_route:
+ IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(inet_csk_route_req);
+
+struct dst_entry *inet_csk_route_child_sock(struct sock *sk,
+ struct sock *newsk,
+ const struct request_sock *req)
+{
+ const struct inet_request_sock *ireq = inet_rsk(req);
+ struct net *net = read_pnet(&ireq->ireq_net);
+ struct inet_sock *newinet = inet_sk(newsk);
+ struct ip_options_rcu *opt;
+ struct flowi4 *fl4;
+ struct rtable *rt;
+
+ fl4 = &newinet->cork.fl.u.ip4;
+
+ rcu_read_lock();
+ opt = rcu_dereference(newinet->inet_opt);
+ flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
+ RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
+ sk->sk_protocol, inet_sk_flowi_flags(sk),
+ (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
+ ireq->ir_loc_addr, ireq->ir_rmt_port,
+ htons(ireq->ir_num));
+ security_req_classify_flow(req, flowi4_to_flowi(fl4));
+ rt = ip_route_output_flow(net, fl4, sk);
+ if (IS_ERR(rt))
+ goto no_route;
+ if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
+ goto route_err;
+ rcu_read_unlock();
+ return &rt->dst;
+
+route_err:
+ ip_rt_put(rt);
+no_route:
+ rcu_read_unlock();
+ IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
+
+static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport,
+ const u32 rnd, const u32 synq_hsize)
+{
+ return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1);
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+#define AF_INET_FAMILY(fam) ((fam) == AF_INET)
+#else
+#define AF_INET_FAMILY(fam) true
+#endif
+
+/* Note: this is temporary :
+ * req sock will no longer be in listener hash table
+*/
+struct request_sock *inet_csk_search_req(struct sock *sk,
+ const __be16 rport,
+ const __be32 raddr,
+ const __be32 laddr)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
+ struct request_sock *req;
+ u32 hash = inet_synq_hash(raddr, rport, lopt->hash_rnd,
+ lopt->nr_table_entries);
+
+ spin_lock(&icsk->icsk_accept_queue.syn_wait_lock);
+ for (req = lopt->syn_table[hash]; req != NULL; req = req->dl_next) {
+ const struct inet_request_sock *ireq = inet_rsk(req);
+
+ if (ireq->ir_rmt_port == rport &&
+ ireq->ir_rmt_addr == raddr &&
+ ireq->ir_loc_addr == laddr &&
+ AF_INET_FAMILY(req->rsk_ops->family)) {
+ atomic_inc(&req->rsk_refcnt);
+ WARN_ON(req->sk);
+ break;
+ }
+ }
+ spin_unlock(&icsk->icsk_accept_queue.syn_wait_lock);
+
+ return req;
+}
+EXPORT_SYMBOL_GPL(inet_csk_search_req);
+
+void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
+ unsigned long timeout)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
+ const u32 h = inet_synq_hash(inet_rsk(req)->ir_rmt_addr,
+ inet_rsk(req)->ir_rmt_port,
+ lopt->hash_rnd, lopt->nr_table_entries);
+
+ reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
+ inet_csk_reqsk_queue_added(sk, timeout);
+}
+EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
+
+/* Only thing we need from tcp.h */
+extern int sysctl_tcp_synack_retries;
+
+
+/* Decide when to expire the request and when to resend SYN-ACK */
+static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
+ const int max_retries,
+ const u8 rskq_defer_accept,
+ int *expire, int *resend)
+{
+ if (!rskq_defer_accept) {
+ *expire = req->num_timeout >= thresh;
+ *resend = 1;
+ return;
+ }
+ *expire = req->num_timeout >= thresh &&
+ (!inet_rsk(req)->acked || req->num_timeout >= max_retries);
+ /*
+ * Do not resend while waiting for data after ACK,
+ * start to resend on end of deferring period to give
+ * last chance for data or ACK to create established socket.
+ */
+ *resend = !inet_rsk(req)->acked ||
+ req->num_timeout >= rskq_defer_accept - 1;
+}
+
+int inet_rtx_syn_ack(struct sock *parent, struct request_sock *req)
+{
+ int err = req->rsk_ops->rtx_syn_ack(parent, req);
+
+ if (!err)
+ req->num_retrans++;
+ return err;
+}
+EXPORT_SYMBOL(inet_rtx_syn_ack);
+
+/* return true if req was found in the syn_table[] */
+static bool reqsk_queue_unlink(struct request_sock_queue *queue,
+ struct request_sock *req)
+{
+ struct listen_sock *lopt = queue->listen_opt;
+ struct request_sock **prev;
+ bool found = false;
+
+ spin_lock(&queue->syn_wait_lock);
+
+ for (prev = &lopt->syn_table[req->rsk_hash]; *prev != NULL;
+ prev = &(*prev)->dl_next) {
+ if (*prev == req) {
+ *prev = req->dl_next;
+ found = true;
+ break;
+ }
+ }
+
+ spin_unlock(&queue->syn_wait_lock);
+ if (del_timer(&req->rsk_timer))
+ reqsk_put(req);
+ return found;
+}
+
+void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
+{
+ if (reqsk_queue_unlink(&inet_csk(sk)->icsk_accept_queue, req)) {
+ reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
+ reqsk_put(req);
+ }
+}
+EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
+
+static void reqsk_timer_handler(unsigned long data)
+{
+ struct request_sock *req = (struct request_sock *)data;
+ struct sock *sk_listener = req->rsk_listener;
+ struct inet_connection_sock *icsk = inet_csk(sk_listener);
+ struct request_sock_queue *queue = &icsk->icsk_accept_queue;
+ struct listen_sock *lopt = queue->listen_opt;
+ int qlen, expire = 0, resend = 0;
+ int max_retries, thresh;
+ u8 defer_accept;
+
+ if (sk_listener->sk_state != TCP_LISTEN || !lopt) {
+ reqsk_put(req);
+ return;
+ }
+
+ max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries;
+ thresh = max_retries;
+ /* Normally all the openreqs are young and become mature
+ * (i.e. converted to established socket) for first timeout.
+ * If synack was not acknowledged for 1 second, it means
+ * one of the following things: synack was lost, ack was lost,
+ * rtt is high or nobody planned to ack (i.e. synflood).
+ * When server is a bit loaded, queue is populated with old
+ * open requests, reducing effective size of queue.
+ * When server is well loaded, queue size reduces to zero
+ * after several minutes of work. It is not synflood,
+ * it is normal operation. The solution is pruning
+ * too old entries overriding normal timeout, when
+ * situation becomes dangerous.
+ *
+ * Essentially, we reserve half of room for young
+ * embrions; and abort old ones without pity, if old
+ * ones are about to clog our table.
+ */
+ qlen = listen_sock_qlen(lopt);
+ if (qlen >> (lopt->max_qlen_log - 1)) {
+ int young = listen_sock_young(lopt) << 1;
+
+ while (thresh > 2) {
+ if (qlen < young)
+ break;
+ thresh--;
+ young <<= 1;
+ }
+ }
+ defer_accept = READ_ONCE(queue->rskq_defer_accept);
+ if (defer_accept)
+ max_retries = defer_accept;
+ syn_ack_recalc(req, thresh, max_retries, defer_accept,
+ &expire, &resend);
+ req->rsk_ops->syn_ack_timeout(req);
+ if (!expire &&
+ (!resend ||
+ !inet_rtx_syn_ack(sk_listener, req) ||
+ inet_rsk(req)->acked)) {
+ unsigned long timeo;
+
+ if (req->num_timeout++ == 0)
+ atomic_inc(&lopt->young_dec);
+ timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
+ mod_timer_pinned(&req->rsk_timer, jiffies + timeo);
+ return;
+ }
+ inet_csk_reqsk_queue_drop(sk_listener, req);
+ reqsk_put(req);
+}
+
+void reqsk_queue_hash_req(struct request_sock_queue *queue,
+ u32 hash, struct request_sock *req,
+ unsigned long timeout)
+{
+ struct listen_sock *lopt = queue->listen_opt;
+
+ req->num_retrans = 0;
+ req->num_timeout = 0;
+ req->sk = NULL;
+
+ /* before letting lookups find us, make sure all req fields
+ * are committed to memory and refcnt initialized.
+ */
+ smp_wmb();
+ atomic_set(&req->rsk_refcnt, 2);
+ setup_timer(&req->rsk_timer, reqsk_timer_handler, (unsigned long)req);
+ req->rsk_hash = hash;
+
+ spin_lock(&queue->syn_wait_lock);
+ req->dl_next = lopt->syn_table[hash];
+ lopt->syn_table[hash] = req;
+ spin_unlock(&queue->syn_wait_lock);
+
+ mod_timer_pinned(&req->rsk_timer, jiffies + timeout);
+}
+EXPORT_SYMBOL(reqsk_queue_hash_req);
+
+/**
+ * inet_csk_clone_lock - clone an inet socket, and lock its clone
+ * @sk: the socket to clone
+ * @req: request_sock
+ * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
+ *
+ * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
+ */
+struct sock *inet_csk_clone_lock(const struct sock *sk,
+ const struct request_sock *req,
+ const gfp_t priority)
+{
+ struct sock *newsk = sk_clone_lock(sk, priority);
+
+ if (newsk) {
+ struct inet_connection_sock *newicsk = inet_csk(newsk);
+
+ newsk->sk_state = TCP_SYN_RECV;
+ newicsk->icsk_bind_hash = NULL;
+
+ inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
+ inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num;
+ inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
+ newsk->sk_write_space = sk_stream_write_space;
+
+ newsk->sk_mark = inet_rsk(req)->ir_mark;
+ atomic64_set(&newsk->sk_cookie,
+ atomic64_read(&inet_rsk(req)->ir_cookie));
+
+ newicsk->icsk_retransmits = 0;
+ newicsk->icsk_backoff = 0;
+ newicsk->icsk_probes_out = 0;
+
+ /* Deinitialize accept_queue to trap illegal accesses. */
+ memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
+
+ security_inet_csk_clone(newsk, req);
+ }
+ return newsk;
+}
+EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
+
+/*
+ * At this point, there should be no process reference to this
+ * socket, and thus no user references at all. Therefore we
+ * can assume the socket waitqueue is inactive and nobody will
+ * try to jump onto it.
+ */
+void inet_csk_destroy_sock(struct sock *sk)
+{
+ WARN_ON(sk->sk_state != TCP_CLOSE);
+ WARN_ON(!sock_flag(sk, SOCK_DEAD));
+
+ /* It cannot be in hash table! */
+ WARN_ON(!sk_unhashed(sk));
+
+ /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
+ WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
+
+ sk->sk_prot->destroy(sk);
+
+ sk_stream_kill_queues(sk);
+
+ xfrm_sk_free_policy(sk);
+
+ sk_refcnt_debug_release(sk);
+
+ percpu_counter_dec(sk->sk_prot->orphan_count);
+ sock_put(sk);
+}
+EXPORT_SYMBOL(inet_csk_destroy_sock);
+
+/* This function allows to force a closure of a socket after the call to
+ * tcp/dccp_create_openreq_child().
+ */
+void inet_csk_prepare_forced_close(struct sock *sk)
+ __releases(&sk->sk_lock.slock)
+{
+ /* sk_clone_lock locked the socket and set refcnt to 2 */
+ bh_unlock_sock(sk);
+ sock_put(sk);
+
+ /* The below has to be done to allow calling inet_csk_destroy_sock */
+ sock_set_flag(sk, SOCK_DEAD);
+ percpu_counter_inc(sk->sk_prot->orphan_count);
+ inet_sk(sk)->inet_num = 0;
+}
+EXPORT_SYMBOL(inet_csk_prepare_forced_close);
+
+int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
+{
+ struct inet_sock *inet = inet_sk(sk);
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries);
+
+ if (rc != 0)
+ return rc;
+
+ sk->sk_max_ack_backlog = 0;
+ sk->sk_ack_backlog = 0;
+ inet_csk_delack_init(sk);
+
+ /* There is race window here: we announce ourselves listening,
+ * but this transition is still not validated by get_port().
+ * It is OK, because this socket enters to hash table only
+ * after validation is complete.
+ */
+ sk->sk_state = TCP_LISTEN;
+ if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
+ inet->inet_sport = htons(inet->inet_num);
+
+ sk_dst_reset(sk);
+ sk->sk_prot->hash(sk);
+
+ return 0;
+ }
+
+ sk->sk_state = TCP_CLOSE;
+ __reqsk_queue_destroy(&icsk->icsk_accept_queue);
+ return -EADDRINUSE;
+}
+EXPORT_SYMBOL_GPL(inet_csk_listen_start);
+
+/*
+ * This routine closes sockets which have been at least partially
+ * opened, but not yet accepted.
+ */
+void inet_csk_listen_stop(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct request_sock_queue *queue = &icsk->icsk_accept_queue;
+ struct request_sock *acc_req;
+ struct request_sock *req;
+
+ /* make all the listen_opt local to us */
+ acc_req = reqsk_queue_yank_acceptq(queue);
+
+ /* Following specs, it would be better either to send FIN
+ * (and enter FIN-WAIT-1, it is normal close)
+ * or to send active reset (abort).
+ * Certainly, it is pretty dangerous while synflood, but it is
+ * bad justification for our negligence 8)
+ * To be honest, we are not able to make either
+ * of the variants now. --ANK
+ */
+ reqsk_queue_destroy(queue);
+
+ while ((req = acc_req) != NULL) {
+ struct sock *child = req->sk;
+
+ acc_req = req->dl_next;
+
+ local_bh_disable();
+ bh_lock_sock(child);
+ WARN_ON(sock_owned_by_user(child));
+ sock_hold(child);
+
+ sk->sk_prot->disconnect(child, O_NONBLOCK);
+
+ sock_orphan(child);
+
+ percpu_counter_inc(sk->sk_prot->orphan_count);
+
+ if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
+ BUG_ON(tcp_sk(child)->fastopen_rsk != req);
+ BUG_ON(sk != req->rsk_listener);
+
+ /* Paranoid, to prevent race condition if
+ * an inbound pkt destined for child is
+ * blocked by sock lock in tcp_v4_rcv().
+ * Also to satisfy an assertion in
+ * tcp_v4_destroy_sock().
+ */
+ tcp_sk(child)->fastopen_rsk = NULL;
+ }
+ inet_csk_destroy_sock(child);
+
+ bh_unlock_sock(child);
+ local_bh_enable();
+ sock_put(child);
+
+ sk_acceptq_removed(sk);
+ reqsk_put(req);
+ }
+ if (queue->fastopenq) {
+ /* Free all the reqs queued in rskq_rst_head. */
+ spin_lock_bh(&queue->fastopenq->lock);
+ acc_req = queue->fastopenq->rskq_rst_head;
+ queue->fastopenq->rskq_rst_head = NULL;
+ spin_unlock_bh(&queue->fastopenq->lock);
+ while ((req = acc_req) != NULL) {
+ acc_req = req->dl_next;
+ reqsk_put(req);
+ }
+ }
+ WARN_ON(sk->sk_ack_backlog);
+}
+EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
+
+void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
+{
+ struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
+ const struct inet_sock *inet = inet_sk(sk);
+
+ sin->sin_family = AF_INET;
+ sin->sin_addr.s_addr = inet->inet_daddr;
+ sin->sin_port = inet->inet_dport;
+}
+EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
+
+#ifdef CONFIG_COMPAT
+int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
+ char __user *optval, int __user *optlen)
+{
+ const struct inet_connection_sock *icsk = inet_csk(sk);
+
+ if (icsk->icsk_af_ops->compat_getsockopt)
+ return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
+ optval, optlen);
+ return icsk->icsk_af_ops->getsockopt(sk, level, optname,
+ optval, optlen);
+}
+EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
+
+int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
+ char __user *optval, unsigned int optlen)
+{
+ const struct inet_connection_sock *icsk = inet_csk(sk);
+
+ if (icsk->icsk_af_ops->compat_setsockopt)
+ return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
+ optval, optlen);
+ return icsk->icsk_af_ops->setsockopt(sk, level, optname,
+ optval, optlen);
+}
+EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
+#endif
+
+static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
+{
+ const struct inet_sock *inet = inet_sk(sk);
+ const struct ip_options_rcu *inet_opt;
+ __be32 daddr = inet->inet_daddr;
+ struct flowi4 *fl4;
+ struct rtable *rt;
+
+ rcu_read_lock();
+ inet_opt = rcu_dereference(inet->inet_opt);
+ if (inet_opt && inet_opt->opt.srr)
+ daddr = inet_opt->opt.faddr;
+ fl4 = &fl->u.ip4;
+ rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
+ inet->inet_saddr, inet->inet_dport,
+ inet->inet_sport, sk->sk_protocol,
+ RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
+ if (IS_ERR(rt))
+ rt = NULL;
+ if (rt)
+ sk_setup_caps(sk, &rt->dst);
+ rcu_read_unlock();
+
+ return &rt->dst;
+}
+
+struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
+{
+ struct dst_entry *dst = __sk_dst_check(sk, 0);
+ struct inet_sock *inet = inet_sk(sk);
+
+ if (!dst) {
+ dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
+ if (!dst)
+ goto out;
+ }
+ dst->ops->update_pmtu(dst, sk, NULL, mtu);
+
+ dst = __sk_dst_check(sk, 0);
+ if (!dst)
+ dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
+out:
+ return dst;
+}
+EXPORT_SYMBOL_GPL(inet_csk_update_pmtu);