[INET]: Generalise tcp_v4_hash_connect

Renaming it to inet_hash_connect, making it possible to ditch
dccp_v4_hash_connect and share the same code with TCP instead.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 178 insertions, 0 deletions

diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index e8d29fe736d2..33228115cda4 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -15,12 +15,14 @@
 
 #include <linux/config.h>
 #include <linux/module.h>
+#include <linux/random.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/wait.h>
 
 #include <net/inet_connection_sock.h>
 #include <net/inet_hashtables.h>
+#include <net/ip.h>
 
 /*
  * Allocate and initialize a new local port bind bucket.
@@ -163,3 +165,179 @@ struct sock *__inet_lookup_listener(const struct hlist_head *head, const u32 dad
 }
 
 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
+
+/* called with local bh disabled */
+static int __inet_check_established(struct inet_timewait_death_row *death_row,
+                                    struct sock *sk, __u16 lport,
+                                    struct inet_timewait_sock **twp)
+{
+        struct inet_hashinfo *hinfo = death_row->hashinfo;
+        struct inet_sock *inet = inet_sk(sk);
+        u32 daddr = inet->rcv_saddr;
+        u32 saddr = inet->daddr;
+        int dif = sk->sk_bound_dev_if;
+        INET_ADDR_COOKIE(acookie, saddr, daddr)
+        const __u32 ports = INET_COMBINED_PORTS(inet->dport, lport);
+        unsigned int hash = inet_ehashfn(daddr, lport, saddr, inet->dport);
+        struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
+        struct sock *sk2;
+        const struct hlist_node *node;
+        struct inet_timewait_sock *tw;
+
+        prefetch(head->chain.first);
+        write_lock(&head->lock);
+
+        /* Check TIME-WAIT sockets first. */
+        sk_for_each(sk2, node, &(head + hinfo->ehash_size)->chain) {
+                tw = inet_twsk(sk2);
+
+                if (INET_TW_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif)) {
+                        if (twsk_unique(sk, sk2, twp))
+                                goto unique;
+                        else
+                                goto not_unique;
+                }
+        }
+        tw = NULL;
+
+        /* And established part... */
+        sk_for_each(sk2, node, &head->chain) {
+                if (INET_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif))
+                        goto not_unique;
+        }
+
+unique:
+        /* Must record num and sport now. Otherwise we will see
+         * in hash table socket with a funny identity. */
+        inet->num = lport;
+        inet->sport = htons(lport);
+        sk->sk_hash = hash;
+        BUG_TRAP(sk_unhashed(sk));
+        __sk_add_node(sk, &head->chain);
+        sock_prot_inc_use(sk->sk_prot);
+        write_unlock(&head->lock);
+
+        if (twp) {
+                *twp = tw;
+                NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
+        } else if (tw) {
+                /* Silly. Should hash-dance instead... */
+                inet_twsk_deschedule(tw, death_row);
+                NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
+
+                inet_twsk_put(tw);
+        }
+
+        return 0;
+
+not_unique:
+        write_unlock(&head->lock);
+        return -EADDRNOTAVAIL;
+}
+
+static inline u32 inet_sk_port_offset(const struct sock *sk)
+{
+        const struct inet_sock *inet = inet_sk(sk);
+        return secure_ipv4_port_ephemeral(inet->rcv_saddr, inet->daddr, 
+                                          inet->dport);
+}
+
+/*
+ * Bind a port for a connect operation and hash it.
+ */
+int inet_hash_connect(struct inet_timewait_death_row *death_row,
+                      struct sock *sk)
+{
+        struct inet_hashinfo *hinfo = death_row->hashinfo;
+        const unsigned short snum = inet_sk(sk)->num;
+        struct inet_bind_hashbucket *head;
+        struct inet_bind_bucket *tb;
+        int ret;
+
+        if (!snum) {
+                int low = sysctl_local_port_range[0];
+                int high = sysctl_local_port_range[1];
+                int range = high - low;
+                int i;
+                int port;
+                static u32 hint;
+                u32 offset = hint + inet_sk_port_offset(sk);
+                struct hlist_node *node;
+                struct inet_timewait_sock *tw = NULL;
+
+                local_bh_disable();
+                for (i = 1; i <= range; i++) {
+                        port = low + (i + offset) % range;
+                        head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)];
+                        spin_lock(&head->lock);
+
+                        /* Does not bother with rcv_saddr checks,
+                         * because the established check is already
+                         * unique enough.
+                         */
+                        inet_bind_bucket_for_each(tb, node, &head->chain) {
+                                if (tb->port == port) {
+                                        BUG_TRAP(!hlist_empty(&tb->owners));
+                                        if (tb->fastreuse >= 0)
+                                                goto next_port;
+                                        if (!__inet_check_established(death_row,
+                                                                      sk, port,
+                                                                      &tw))
+                                                goto ok;
+                                        goto next_port;
+                                }
+                        }
+
+                        tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, head, port);
+                        if (!tb) {
+                                spin_unlock(&head->lock);
+                                break;
+                        }
+                        tb->fastreuse = -1;
+                        goto ok;
+
+                next_port:
+                        spin_unlock(&head->lock);
+                }
+                local_bh_enable();
+
+                return -EADDRNOTAVAIL;
+
+ok:
+                hint += i;
+
+                /* Head lock still held and bh's disabled */
+                inet_bind_hash(sk, tb, port);
+                if (sk_unhashed(sk)) {
+                        inet_sk(sk)->sport = htons(port);
+                        __inet_hash(hinfo, sk, 0);
+                }
+                spin_unlock(&head->lock);
+
+                if (tw) {
+                        inet_twsk_deschedule(tw, death_row);;
+                        inet_twsk_put(tw);
+                }
+
+                ret = 0;
+                goto out;
+        }
+
+        head = &hinfo->bhash[inet_bhashfn(snum, hinfo->bhash_size)];
+        tb  = inet_csk(sk)->icsk_bind_hash;
+        spin_lock_bh(&head->lock);
+        if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
+                __inet_hash(hinfo, sk, 0);
+                spin_unlock_bh(&head->lock);
+                return 0;
+        } else {
+                spin_unlock(&head->lock);
+                /* No definite answer... Walk to established hash table */
+                ret = __inet_check_established(death_row, sk, snum, NULL);
+out:
+                local_bh_enable();
+                return ret;
+        }
+}
+
+EXPORT_SYMBOL_GPL(inet_hash_connect);