| /* |
| * 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> |
| #include <net/sock_reuseport.h> |
| #include <net/addrconf.h> |
| |
| #if IS_ENABLED(CONFIG_IPV6) |
| /* match_wildcard == true: IPV6_ADDR_ANY equals to any IPv6 addresses if IPv6 |
| * only, and any IPv4 addresses if not IPv6 only |
| * match_wildcard == false: addresses must be exactly the same, i.e. |
| * IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY, |
| * and 0.0.0.0 equals to 0.0.0.0 only |
| */ |
| static bool ipv6_rcv_saddr_equal(const struct in6_addr *sk1_rcv_saddr6, |
| const struct in6_addr *sk2_rcv_saddr6, |
| __be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr, |
| bool sk1_ipv6only, bool sk2_ipv6only, |
| bool match_wildcard) |
| { |
| int addr_type = ipv6_addr_type(sk1_rcv_saddr6); |
| int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED; |
| |
| /* if both are mapped, treat as IPv4 */ |
| if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) { |
| if (!sk2_ipv6only) { |
| if (sk1_rcv_saddr == sk2_rcv_saddr) |
| return true; |
| if (!sk1_rcv_saddr || !sk2_rcv_saddr) |
| return match_wildcard; |
| } |
| return false; |
| } |
| |
| if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY) |
| return true; |
| |
| if (addr_type2 == IPV6_ADDR_ANY && match_wildcard && |
| !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED)) |
| return true; |
| |
| if (addr_type == IPV6_ADDR_ANY && match_wildcard && |
| !(sk1_ipv6only && addr_type2 == IPV6_ADDR_MAPPED)) |
| return true; |
| |
| if (sk2_rcv_saddr6 && |
| ipv6_addr_equal(sk1_rcv_saddr6, sk2_rcv_saddr6)) |
| return true; |
| |
| return false; |
| } |
| #endif |
| |
| /* match_wildcard == true: 0.0.0.0 equals to any IPv4 addresses |
| * match_wildcard == false: addresses must be exactly the same, i.e. |
| * 0.0.0.0 only equals to 0.0.0.0 |
| */ |
| static bool ipv4_rcv_saddr_equal(__be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr, |
| bool sk2_ipv6only, bool match_wildcard) |
| { |
| if (!sk2_ipv6only) { |
| if (sk1_rcv_saddr == sk2_rcv_saddr) |
| return true; |
| if (!sk1_rcv_saddr || !sk2_rcv_saddr) |
| return match_wildcard; |
| } |
| return false; |
| } |
| |
| bool inet_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2, |
| bool match_wildcard) |
| { |
| #if IS_ENABLED(CONFIG_IPV6) |
| if (sk->sk_family == AF_INET6) |
| return ipv6_rcv_saddr_equal(&sk->sk_v6_rcv_saddr, |
| inet6_rcv_saddr(sk2), |
| sk->sk_rcv_saddr, |
| sk2->sk_rcv_saddr, |
| ipv6_only_sock(sk), |
| ipv6_only_sock(sk2), |
| match_wildcard); |
| #endif |
| return ipv4_rcv_saddr_equal(sk->sk_rcv_saddr, sk2->sk_rcv_saddr, |
| ipv6_only_sock(sk2), match_wildcard); |
| } |
| EXPORT_SYMBOL(inet_rcv_saddr_equal); |
| |
| bool inet_rcv_saddr_any(const struct sock *sk) |
| { |
| #if IS_ENABLED(CONFIG_IPV6) |
| if (sk->sk_family == AF_INET6) |
| return ipv6_addr_any(&sk->sk_v6_rcv_saddr); |
| #endif |
| return !sk->sk_rcv_saddr; |
| } |
| |
| 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); |
| |
| static int inet_csk_bind_conflict(const struct sock *sk, |
| const struct inet_bind_bucket *tb, |
| bool relax, bool reuseport_ok) |
| { |
| struct sock *sk2; |
| bool reuse = sk->sk_reuse; |
| bool reuseport = !!sk->sk_reuseport && reuseport_ok; |
| 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 && |
| (!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 || |
| rcu_access_pointer(sk->sk_reuseport_cb) || |
| (sk2->sk_state != TCP_TIME_WAIT && |
| !uid_eq(uid, sock_i_uid(sk2))))) { |
| if (inet_rcv_saddr_equal(sk, sk2, true)) |
| break; |
| } |
| if (!relax && reuse && sk2->sk_reuse && |
| sk2->sk_state != TCP_LISTEN) { |
| if (inet_rcv_saddr_equal(sk, sk2, true)) |
| break; |
| } |
| } |
| } |
| return sk2 != NULL; |
| } |
| |
| /* |
| * Find an open port number for the socket. Returns with the |
| * inet_bind_hashbucket lock held. |
| */ |
| static struct inet_bind_hashbucket * |
| inet_csk_find_open_port(struct sock *sk, struct inet_bind_bucket **tb_ret, int *port_ret) |
| { |
| struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo; |
| int port = 0; |
| struct inet_bind_hashbucket *head; |
| struct net *net = sock_net(sk); |
| int i, low, high, attempt_half; |
| struct inet_bind_bucket *tb; |
| u32 remaining, offset; |
| int l3mdev; |
| |
| l3mdev = inet_sk_bound_l3mdev(sk); |
| attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0; |
| other_half_scan: |
| inet_get_local_port_range(net, &low, &high); |
| high++; /* [32768, 60999] -> [32768, 61000[ */ |
| if (high - low < 4) |
| attempt_half = 0; |
| if (attempt_half) { |
| int half = low + (((high - low) >> 2) << 1); |
| |
| if (attempt_half == 1) |
| high = half; |
| else |
| low = half; |
| } |
| remaining = high - low; |
| if (likely(remaining > 1)) |
| remaining &= ~1U; |
| |
| offset = prandom_u32() % remaining; |
| /* __inet_hash_connect() favors ports having @low parity |
| * We do the opposite to not pollute connect() users. |
| */ |
| offset |= 1U; |
| |
| other_parity_scan: |
| port = low + offset; |
| for (i = 0; i < remaining; i += 2, port += 2) { |
| if (unlikely(port >= high)) |
| port -= remaining; |
| if (inet_is_local_reserved_port(net, port)) |
| continue; |
| head = &hinfo->bhash[inet_bhashfn(net, port, |
| hinfo->bhash_size)]; |
| spin_lock_bh(&head->lock); |
| inet_bind_bucket_for_each(tb, &head->chain) |
| if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev && |
| tb->port == port) { |
| if (!inet_csk_bind_conflict(sk, tb, false, false)) |
| goto success; |
| goto next_port; |
| } |
| tb = NULL; |
| goto success; |
| next_port: |
| spin_unlock_bh(&head->lock); |
| cond_resched(); |
| } |
| |
| offset--; |
| if (!(offset & 1)) |
| goto other_parity_scan; |
| |
| if (attempt_half == 1) { |
| /* OK we now try the upper half of the range */ |
| attempt_half = 2; |
| goto other_half_scan; |
| } |
| return NULL; |
| success: |
| *port_ret = port; |
| *tb_ret = tb; |
| return head; |
| } |
| |
| static inline int sk_reuseport_match(struct inet_bind_bucket *tb, |
| struct sock *sk) |
| { |
| kuid_t uid = sock_i_uid(sk); |
| |
| if (tb->fastreuseport <= 0) |
| return 0; |
| if (!sk->sk_reuseport) |
| return 0; |
| if (rcu_access_pointer(sk->sk_reuseport_cb)) |
| return 0; |
| if (!uid_eq(tb->fastuid, uid)) |
| return 0; |
| /* We only need to check the rcv_saddr if this tb was once marked |
| * without fastreuseport and then was reset, as we can only know that |
| * the fast_*rcv_saddr doesn't have any conflicts with the socks on the |
| * owners list. |
| */ |
| if (tb->fastreuseport == FASTREUSEPORT_ANY) |
| return 1; |
| #if IS_ENABLED(CONFIG_IPV6) |
| if (tb->fast_sk_family == AF_INET6) |
| return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr, |
| inet6_rcv_saddr(sk), |
| tb->fast_rcv_saddr, |
| sk->sk_rcv_saddr, |
| tb->fast_ipv6_only, |
| ipv6_only_sock(sk), true); |
| #endif |
| return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr, |
| ipv6_only_sock(sk), true); |
| } |
| |
| /* Obtain a reference to a local port for the given sock, |
| * if snum is zero it means select any available local port. |
| * We try to allocate an odd port (and leave even ports for connect()) |
| */ |
| int inet_csk_get_port(struct sock *sk, unsigned short snum) |
| { |
| bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN; |
| struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo; |
| int ret = 1, port = snum; |
| struct inet_bind_hashbucket *head; |
| struct net *net = sock_net(sk); |
| struct inet_bind_bucket *tb = NULL; |
| kuid_t uid = sock_i_uid(sk); |
| int l3mdev; |
| |
| l3mdev = inet_sk_bound_l3mdev(sk); |
| |
| if (!port) { |
| head = inet_csk_find_open_port(sk, &tb, &port); |
| if (!head) |
| return ret; |
| if (!tb) |
| goto tb_not_found; |
| goto success; |
| } |
| head = &hinfo->bhash[inet_bhashfn(net, port, |
| hinfo->bhash_size)]; |
| spin_lock_bh(&head->lock); |
| inet_bind_bucket_for_each(tb, &head->chain) |
| if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev && |
| tb->port == port) |
| goto tb_found; |
| tb_not_found: |
| tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, |
| net, head, port, l3mdev); |
| if (!tb) |
| goto fail_unlock; |
| tb_found: |
| if (!hlist_empty(&tb->owners)) { |
| if (sk->sk_reuse == SK_FORCE_REUSE) |
| goto success; |
| |
| if ((tb->fastreuse > 0 && reuse) || |
| sk_reuseport_match(tb, sk)) |
| goto success; |
| if (inet_csk_bind_conflict(sk, tb, true, true)) |
| goto fail_unlock; |
| } |
| success: |
| if (hlist_empty(&tb->owners)) { |
| tb->fastreuse = reuse; |
| if (sk->sk_reuseport) { |
| tb->fastreuseport = FASTREUSEPORT_ANY; |
| tb->fastuid = uid; |
| tb->fast_rcv_saddr = sk->sk_rcv_saddr; |
| tb->fast_ipv6_only = ipv6_only_sock(sk); |
| tb->fast_sk_family = sk->sk_family; |
| #if IS_ENABLED(CONFIG_IPV6) |
| tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr; |
| #endif |
| } else { |
| tb->fastreuseport = 0; |
| } |
| } else { |
| if (!reuse) |
| tb->fastreuse = 0; |
| if (sk->sk_reuseport) { |
| /* We didn't match or we don't have fastreuseport set on |
| * the tb, but we have sk_reuseport set on this socket |
| * and we know that there are no bind conflicts with |
| * this socket in this tb, so reset our tb's reuseport |
| * settings so that any subsequent sockets that match |
| * our current socket will be put on the fast path. |
| * |
| * If we reset we need to set FASTREUSEPORT_STRICT so we |
| * do extra checking for all subsequent sk_reuseport |
| * socks. |
| */ |
| if (!sk_reuseport_match(tb, sk)) { |
| tb->fastreuseport = FASTREUSEPORT_STRICT; |
| tb->fastuid = uid; |
| tb->fast_rcv_saddr = sk->sk_rcv_saddr; |
| tb->fast_ipv6_only = ipv6_only_sock(sk); |
| tb->fast_sk_family = sk->sk_family; |
| #if IS_ENABLED(CONFIG_IPV6) |
| tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr; |
| #endif |
| } |
| } else { |
| tb->fastreuseport = 0; |
| } |
| } |
| if (!inet_csk(sk)->icsk_bind_hash) |
| inet_bind_hash(sk, tb, port); |
| WARN_ON(inet_csk(sk)->icsk_bind_hash != tb); |
| ret = 0; |
| |
| fail_unlock: |
| spin_unlock_bh(&head->lock); |
| 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, bool kern) |
| { |
| 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, sk); |
| newsk = req->sk; |
| |
| if (sk->sk_protocol == IPPROTO_TCP && |
| tcp_rsk(req)->tfo_listener) { |
| 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)(struct timer_list *t), |
| void (*delack_handler)(struct timer_list *t), |
| void (*keepalive_handler)(struct timer_list *t)) |
| { |
| struct inet_connection_sock *icsk = inet_csk(sk); |
| |
| timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0); |
| timer_setup(&icsk->icsk_delack_timer, delack_handler, 0); |
| timer_setup(&sk->sk_timer, keepalive_handler, 0); |
| 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(const 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; |
| struct rtable *rt; |
| |
| rcu_read_lock(); |
| opt = rcu_dereference(ireq->ireq_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), sk->sk_uid); |
| 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_gw_family) |
| goto route_err; |
| rcu_read_unlock(); |
| return &rt->dst; |
| |
| route_err: |
| ip_rt_put(rt); |
| no_route: |
| rcu_read_unlock(); |
| __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(inet_csk_route_req); |
| |
| struct dst_entry *inet_csk_route_child_sock(const 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; |
| |
| opt = rcu_dereference(ireq->ireq_opt); |
| fl4 = &newinet->cork.fl.u.ip4; |
| |
| 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), sk->sk_uid); |
| 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_gw_family) |
| goto route_err; |
| return &rt->dst; |
| |
| route_err: |
| ip_rt_put(rt); |
| no_route: |
| __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(inet_csk_route_child_sock); |
| |
| #if IS_ENABLED(CONFIG_IPV6) |
| #define AF_INET_FAMILY(fam) ((fam) == AF_INET) |
| #else |
| #define AF_INET_FAMILY(fam) true |
| #endif |
| |
| /* 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(const 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 ehash table */ |
| static bool reqsk_queue_unlink(struct request_sock_queue *queue, |
| struct request_sock *req) |
| { |
| struct inet_hashinfo *hashinfo = req_to_sk(req)->sk_prot->h.hashinfo; |
| bool found = false; |
| |
| if (sk_hashed(req_to_sk(req))) { |
| spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash); |
| |
| spin_lock(lock); |
| found = __sk_nulls_del_node_init_rcu(req_to_sk(req)); |
| spin_unlock(lock); |
| } |
| if (timer_pending(&req->rsk_timer) && del_timer_sync(&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); |
| |
| void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req) |
| { |
| inet_csk_reqsk_queue_drop(sk, req); |
| reqsk_put(req); |
| } |
| EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put); |
| |
| static void reqsk_timer_handler(struct timer_list *t) |
| { |
| struct request_sock *req = from_timer(req, t, rsk_timer); |
| struct sock *sk_listener = req->rsk_listener; |
| struct net *net = sock_net(sk_listener); |
| struct inet_connection_sock *icsk = inet_csk(sk_listener); |
| struct request_sock_queue *queue = &icsk->icsk_accept_queue; |
| int qlen, expire = 0, resend = 0; |
| int max_retries, thresh; |
| u8 defer_accept; |
| |
| if (inet_sk_state_load(sk_listener) != TCP_LISTEN) |
| goto drop; |
| |
| max_retries = icsk->icsk_syn_retries ? : net->ipv4.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 = reqsk_queue_len(queue); |
| if ((qlen << 1) > max(8U, sk_listener->sk_max_ack_backlog)) { |
| int young = reqsk_queue_len_young(queue) << 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_dec(&queue->young); |
| timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX); |
| mod_timer(&req->rsk_timer, jiffies + timeo); |
| return; |
| } |
| drop: |
| inet_csk_reqsk_queue_drop_and_put(sk_listener, req); |
| } |
| |
| static void reqsk_queue_hash_req(struct request_sock *req, |
| unsigned long timeout) |
| { |
| req->num_retrans = 0; |
| req->num_timeout = 0; |
| req->sk = NULL; |
| |
| timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED); |
| mod_timer(&req->rsk_timer, jiffies + timeout); |
| |
| inet_ehash_insert(req_to_sk(req), NULL); |
| /* before letting lookups find us, make sure all req fields |
| * are committed to memory and refcnt initialized. |
| */ |
| smp_wmb(); |
| refcount_set(&req->rsk_refcnt, 2 + 1); |
| } |
| |
| void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req, |
| unsigned long timeout) |
| { |
| reqsk_queue_hash_req(req, timeout); |
| inet_csk_reqsk_queue_added(sk); |
| } |
| EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add); |
| |
| /** |
| * 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); |
| |
| inet_sk_set_state(newsk, 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); |
| |
| /* listeners have SOCK_RCU_FREE, not the children */ |
| sock_reset_flag(newsk, SOCK_RCU_FREE); |
| |
| inet_sk(newsk)->mc_list = NULL; |
| |
| 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, int backlog) |
| { |
| struct inet_connection_sock *icsk = inet_csk(sk); |
| struct inet_sock *inet = inet_sk(sk); |
| int err = -EADDRINUSE; |
| |
| reqsk_queue_alloc(&icsk->icsk_accept_queue); |
| |
| 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. |
| */ |
| inet_sk_state_store(sk, TCP_LISTEN); |
| if (!sk->sk_prot->get_port(sk, inet->inet_num)) { |
| inet->inet_sport = htons(inet->inet_num); |
| |
| sk_dst_reset(sk); |
| err = sk->sk_prot->hash(sk); |
| |
| if (likely(!err)) |
| return 0; |
| } |
| |
| inet_sk_set_state(sk, TCP_CLOSE); |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(inet_csk_listen_start); |
| |
| static void inet_child_forget(struct sock *sk, struct request_sock *req, |
| struct sock *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); |
| } |
| |
| struct sock *inet_csk_reqsk_queue_add(struct sock *sk, |
| struct request_sock *req, |
| struct sock *child) |
| { |
| struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue; |
| |
| spin_lock(&queue->rskq_lock); |
| if (unlikely(sk->sk_state != TCP_LISTEN)) { |
| inet_child_forget(sk, req, child); |
| child = NULL; |
| } else { |
| req->sk = child; |
| req->dl_next = NULL; |
| if (queue->rskq_accept_head == NULL) |
| queue->rskq_accept_head = req; |
| else |
| queue->rskq_accept_tail->dl_next = req; |
| queue->rskq_accept_tail = req; |
| sk_acceptq_added(sk); |
| } |
| spin_unlock(&queue->rskq_lock); |
| return child; |
| } |
| EXPORT_SYMBOL(inet_csk_reqsk_queue_add); |
| |
| struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child, |
| struct request_sock *req, bool own_req) |
| { |
| if (own_req) { |
| inet_csk_reqsk_queue_drop(sk, req); |
| reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req); |
| if (inet_csk_reqsk_queue_add(sk, req, child)) |
| return child; |
| } |
| /* Too bad, another child took ownership of the request, undo. */ |
| bh_unlock_sock(child); |
| sock_put(child); |
| return NULL; |
| } |
| EXPORT_SYMBOL(inet_csk_complete_hashdance); |
| |
| /* |
| * 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 *next, *req; |
| |
| /* 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 |
| */ |
| while ((req = reqsk_queue_remove(queue, sk)) != NULL) { |
| struct sock *child = req->sk; |
| |
| local_bh_disable(); |
| bh_lock_sock(child); |
| WARN_ON(sock_owned_by_user(child)); |
| sock_hold(child); |
| |
| inet_child_forget(sk, req, child); |
| reqsk_put(req); |
| bh_unlock_sock(child); |
| local_bh_enable(); |
| sock_put(child); |
| |
| cond_resched(); |
| } |
| if (queue->fastopenq.rskq_rst_head) { |
| /* Free all the reqs queued in rskq_rst_head. */ |
| spin_lock_bh(&queue->fastopenq.lock); |
| req = queue->fastopenq.rskq_rst_head; |
| queue->fastopenq.rskq_rst_head = NULL; |
| spin_unlock_bh(&queue->fastopenq.lock); |
| while (req != NULL) { |
| next = req->dl_next; |
| reqsk_put(req); |
| req = next; |
| } |
| } |
| WARN_ON_ONCE(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); |