[PATCH] tcp: documents timewait refcnt tricks
[safe/jmp/linux-2.6] / net / ipv4 / inet_connection_sock.c
index 3fe021f..ee16475 100644 (file)
@@ -13,7 +13,6 @@
  *             2 of the License, or(at your option) any later version.
  */
 
-#include <linux/config.h>
 #include <linux/module.h>
 #include <linux/jhash.h>
 
@@ -31,19 +30,40 @@ EXPORT_SYMBOL(inet_csk_timer_bug_msg);
 #endif
 
 /*
- * This array holds the first and last local port number.
- * For high-usage systems, use sysctl to change this to
- * 32768-61000
+ * This struct holds the first and last local port number.
  */
-int sysctl_local_port_range[2] = { 1024, 4999 };
+struct local_ports sysctl_local_ports __read_mostly = {
+       .lock = SEQLOCK_UNLOCKED,
+       .range = { 32768, 61000 },
+};
 
-static inline int inet_csk_bind_conflict(struct sock *sk, struct inet_bind_bucket *tb)
+void inet_get_local_port_range(int *low, int *high)
 {
-       const u32 sk_rcv_saddr = inet_rcv_saddr(sk);
+       unsigned seq;
+       do {
+               seq = read_seqbegin(&sysctl_local_ports.lock);
+
+               *low = sysctl_local_ports.range[0];
+               *high = sysctl_local_ports.range[1];
+       } while (read_seqretry(&sysctl_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)
+{
+       const __be32 sk_rcv_saddr = inet_rcv_saddr(sk);
        struct sock *sk2;
        struct hlist_node *node;
        int reuse = sk->sk_reuse;
 
+       /*
+        * 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, node, &tb->owners) {
                if (sk != sk2 &&
                    !inet_v6_ipv6only(sk2) &&
@@ -52,7 +72,7 @@ static inline int inet_csk_bind_conflict(struct sock *sk, struct inet_bind_bucke
                     sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
                        if (!reuse || !sk2->sk_reuse ||
                            sk2->sk_state == TCP_LISTEN) {
-                               const u32 sk2_rcv_saddr = inet_rcv_saddr(sk2);
+                               const __be32 sk2_rcv_saddr = inet_rcv_saddr(sk2);
                                if (!sk2_rcv_saddr || !sk_rcv_saddr ||
                                    sk2_rcv_saddr == sk_rcv_saddr)
                                        break;
@@ -62,30 +82,51 @@ static inline int inet_csk_bind_conflict(struct sock *sk, struct inet_bind_bucke
        return node != 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 inet_hashinfo *hashinfo,
-                     struct sock *sk, unsigned short snum)
+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 hlist_node *node;
        struct inet_bind_bucket *tb;
-       int ret;
+       int ret, attempts = 5;
+       struct net *net = sock_net(sk);
+       int smallest_size = -1, smallest_rover;
 
        local_bh_disable();
        if (!snum) {
-               int low = sysctl_local_port_range[0];
-               int high = sysctl_local_port_range[1];
-               int remaining = (high - low) + 1;
-               int rover = net_random() % (high - low) + low;
+               int remaining, rover, low, high;
+
+again:
+               inet_get_local_port_range(&low, &high);
+               remaining = (high - low) + 1;
+               smallest_rover = rover = net_random() % remaining + low;
 
+               smallest_size = -1;
                do {
-                       head = &hashinfo->bhash[inet_bhashfn(rover, hashinfo->bhash_size)];
+                       head = &hashinfo->bhash[inet_bhashfn(net, rover,
+                                       hashinfo->bhash_size)];
                        spin_lock(&head->lock);
                        inet_bind_bucket_for_each(tb, node, &head->chain)
-                               if (tb->port == rover)
+                               if (net_eq(ib_net(tb), net) && tb->port == rover) {
+                                       if (tb->fastreuse > 0 &&
+                                           sk->sk_reuse &&
+                                           sk->sk_state != TCP_LISTEN &&
+                                           (tb->num_owners < smallest_size || smallest_size == -1)) {
+                                               smallest_size = tb->num_owners;
+                                               smallest_rover = rover;
+                                               if (atomic_read(&hashinfo->bsockets) > (high - low) + 1) {
+                                                       spin_unlock(&head->lock);
+                                                       snum = smallest_rover;
+                                                       goto have_snum;
+                                               }
+                                       }
                                        goto next;
+                               }
                        break;
                next:
                        spin_unlock(&head->lock);
@@ -100,38 +141,50 @@ int inet_csk_get_port(struct inet_hashinfo *hashinfo,
                 * the top level, not from the 'break;' statement.
                 */
                ret = 1;
-               if (remaining <= 0)
+               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 {
-               head = &hashinfo->bhash[inet_bhashfn(snum, hashinfo->bhash_size)];
+have_snum:
+               head = &hashinfo->bhash[inet_bhashfn(net, snum,
+                               hashinfo->bhash_size)];
                spin_lock(&head->lock);
                inet_bind_bucket_for_each(tb, node, &head->chain)
-                       if (tb->port == snum)
+                       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 > 1)
-                       goto success;
                if (tb->fastreuse > 0 &&
-                   sk->sk_reuse && sk->sk_state != TCP_LISTEN) {
+                   sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
+                   smallest_size == -1) {
                        goto success;
                } else {
                        ret = 1;
-                       if (inet_csk_bind_conflict(sk, tb))
+                       if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb)) {
+                               if (sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
+                                   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, head, snum)) == NULL)
+       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)
@@ -144,8 +197,8 @@ tb_not_found:
 success:
        if (!inet_csk(sk)->icsk_bind_hash)
                inet_bind_hash(sk, tb, snum);
-       BUG_TRAP(inet_csk(sk)->icsk_bind_hash == tb);
-       ret = 0;
+       WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
+       ret = 0;
 
 fail_unlock:
        spin_unlock(&head->lock);
@@ -237,7 +290,7 @@ struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
        }
 
        newsk = reqsk_queue_get_child(&icsk->icsk_accept_queue, sk);
-       BUG_TRAP(newsk->sk_state != TCP_SYN_RECV);
+       WARN_ON(newsk->sk_state == TCP_SYN_RECV);
 out:
        release_sock(sk);
        return newsk;
@@ -251,7 +304,7 @@ 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 
+ * We may wish use just one timer maintaining a list of expire jiffies
  * to optimize.
  */
 void inet_csk_init_xmit_timers(struct sock *sk,
@@ -261,18 +314,11 @@ void inet_csk_init_xmit_timers(struct sock *sk,
 {
        struct inet_connection_sock *icsk = inet_csk(sk);
 
-       init_timer(&icsk->icsk_retransmit_timer);
-       init_timer(&icsk->icsk_delack_timer);
-       init_timer(&sk->sk_timer);
-
-       icsk->icsk_retransmit_timer.function = retransmit_handler;
-       icsk->icsk_delack_timer.function     = delack_handler;
-       sk->sk_timer.function                = keepalive_handler;
-
-       icsk->icsk_retransmit_timer.data = 
-               icsk->icsk_delack_timer.data =
-                       sk->sk_timer.data  = (unsigned long)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;
 }
 
@@ -305,13 +351,14 @@ void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
 
 EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
 
-struct dst_entryinet_csk_route_req(struct sock *sk,
+struct dst_entry *inet_csk_route_req(struct sock *sk,
                                     const struct request_sock *req)
 {
        struct rtable *rt;
        const struct inet_request_sock *ireq = inet_rsk(req);
        struct ip_options *opt = inet_rsk(req)->opt;
        struct flowi fl = { .oif = sk->sk_bound_dev_if,
+                           .mark = sk->sk_mark,
                            .nl_u = { .ip4_u =
                                      { .daddr = ((opt && opt->srr) ?
                                                  opt->faddr :
@@ -319,28 +366,32 @@ struct dst_entry* inet_csk_route_req(struct sock *sk,
                                        .saddr = ireq->loc_addr,
                                        .tos = RT_CONN_FLAGS(sk) } },
                            .proto = sk->sk_protocol,
+                           .flags = inet_sk_flowi_flags(sk),
                            .uli_u = { .ports =
-                                      { .sport = inet_sk(sk)->sport,
+                                      { .sport = inet_sk(sk)->inet_sport,
                                         .dport = ireq->rmt_port } } };
+       struct net *net = sock_net(sk);
 
-       if (ip_route_output_flow(&rt, &fl, sk, 0)) {
-               IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
-               return NULL;
-       }
-       if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) {
-               ip_rt_put(rt);
-               IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
-               return NULL;
-       }
+       security_req_classify_flow(req, &fl);
+       if (ip_route_output_flow(net, &rt, &fl, sk, 0))
+               goto no_route;
+       if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway)
+               goto route_err;
        return &rt->u.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);
 
-static inline u32 inet_synq_hash(const u32 raddr, const u16 rport,
-                                const u32 rnd, const u16 synq_hsize)
+static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport,
+                                const u32 rnd, const u32 synq_hsize)
 {
-       return jhash_2words(raddr, (u32)rport, rnd) & (synq_hsize - 1);
+       return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1);
 }
 
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
@@ -351,8 +402,8 @@ static inline u32 inet_synq_hash(const u32 raddr, const u16 rport,
 
 struct request_sock *inet_csk_search_req(const struct sock *sk,
                                         struct request_sock ***prevp,
-                                        const __u16 rport, const __u32 raddr,
-                                        const __u32 laddr)
+                                        const __be16 rport, const __be32 raddr,
+                                        const __be32 laddr)
 {
        const struct inet_connection_sock *icsk = inet_csk(sk);
        struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
@@ -368,7 +419,7 @@ struct request_sock *inet_csk_search_req(const struct sock *sk,
                    ireq->rmt_addr == raddr &&
                    ireq->loc_addr == laddr &&
                    AF_INET_FAMILY(req->rsk_ops->family)) {
-                       BUG_TRAP(!req->sk);
+                       WARN_ON(req->sk);
                        *prevp = prev;
                        break;
                }
@@ -380,7 +431,7 @@ struct request_sock *inet_csk_search_req(const struct sock *sk,
 EXPORT_SYMBOL_GPL(inet_csk_search_req);
 
 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
-                                  const unsigned timeout)
+                                  unsigned long timeout)
 {
        struct inet_connection_sock *icsk = inet_csk(sk);
        struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
@@ -396,6 +447,28 @@ extern int sysctl_tcp_synack_retries;
 
 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
 
+/* 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->retrans >= thresh;
+               *resend = 1;
+               return;
+       }
+       *expire = req->retrans >= thresh &&
+                 (!inet_rsk(req)->acked || req->retrans >= 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->retrans >= rskq_defer_accept - 1;
+}
+
 void inet_csk_reqsk_queue_prune(struct sock *parent,
                                const unsigned long interval,
                                const unsigned long timeout,
@@ -451,9 +524,15 @@ void inet_csk_reqsk_queue_prune(struct sock *parent,
                reqp=&lopt->syn_table[i];
                while ((req = *reqp) != NULL) {
                        if (time_after_eq(now, req->expires)) {
-                               if ((req->retrans < thresh ||
-                                    (inet_rsk(req)->acked && req->retrans < max_retries))
-                                   && !req->rsk_ops->rtx_syn_ack(parent, req, NULL)) {
+                               int expire = 0, resend = 0;
+
+                               syn_ack_recalc(req, thresh, max_retries,
+                                              queue->rskq_defer_accept,
+                                              &expire, &resend);
+                               if (!expire &&
+                                   (!resend ||
+                                    !req->rsk_ops->rtx_syn_ack(parent, req, NULL) ||
+                                    inet_rsk(req)->acked)) {
                                        unsigned long timeo;
 
                                        if (req->retrans++ == 0)
@@ -496,7 +575,9 @@ struct sock *inet_csk_clone(struct sock *sk, const struct request_sock *req,
                newsk->sk_state = TCP_SYN_RECV;
                newicsk->icsk_bind_hash = NULL;
 
-               inet_sk(newsk)->dport = inet_rsk(req)->rmt_port;
+               inet_sk(newsk)->inet_dport = inet_rsk(req)->rmt_port;
+               inet_sk(newsk)->inet_num = ntohs(inet_rsk(req)->loc_port);
+               inet_sk(newsk)->inet_sport = inet_rsk(req)->loc_port;
                newsk->sk_write_space = sk_stream_write_space;
 
                newicsk->icsk_retransmits = 0;
@@ -505,6 +586,8 @@ struct sock *inet_csk_clone(struct sock *sk, const struct request_sock *req,
 
                /* 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;
 }
@@ -519,14 +602,14 @@ EXPORT_SYMBOL_GPL(inet_csk_clone);
  */
 void inet_csk_destroy_sock(struct sock *sk)
 {
-       BUG_TRAP(sk->sk_state == TCP_CLOSE);
-       BUG_TRAP(sock_flag(sk, SOCK_DEAD));
+       WARN_ON(sk->sk_state != TCP_CLOSE);
+       WARN_ON(!sock_flag(sk, SOCK_DEAD));
 
        /* It cannot be in hash table! */
-       BUG_TRAP(sk_unhashed(sk));
+       WARN_ON(!sk_unhashed(sk));
 
-       /* If it has not 0 inet_sk(sk)->num, it must be bound */
-       BUG_TRAP(!inet_sk(sk)->num || inet_csk(sk)->icsk_bind_hash);
+       /* 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);
 
@@ -536,7 +619,7 @@ void inet_csk_destroy_sock(struct sock *sk)
 
        sk_refcnt_debug_release(sk);
 
-       atomic_dec(sk->sk_prot->orphan_count);
+       percpu_counter_dec(sk->sk_prot->orphan_count);
        sock_put(sk);
 }
 
@@ -561,8 +644,8 @@ int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
         * after validation is complete.
         */
        sk->sk_state = TCP_LISTEN;
-       if (!sk->sk_prot->get_port(sk, inet->num)) {
-               inet->sport = htons(inet->num);
+       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);
@@ -609,14 +692,14 @@ void inet_csk_listen_stop(struct sock *sk)
 
                local_bh_disable();
                bh_lock_sock(child);
-               BUG_TRAP(!sock_owned_by_user(child));
+               WARN_ON(sock_owned_by_user(child));
                sock_hold(child);
 
                sk->sk_prot->disconnect(child, O_NONBLOCK);
 
                sock_orphan(child);
 
-               atomic_inc(sk->sk_prot->orphan_count);
+               percpu_counter_inc(sk->sk_prot->orphan_count);
 
                inet_csk_destroy_sock(child);
 
@@ -627,7 +710,49 @@ void inet_csk_listen_stop(struct sock *sk)
                sk_acceptq_removed(sk);
                __reqsk_free(req);
        }
-       BUG_TRAP(!sk->sk_ack_backlog);
+       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 != NULL)
+               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 != NULL)
+               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