1 files changed, 165 insertions, 0 deletions

diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
new file mode 100644
index 000000000000..e8d29fe736d2
--- /dev/null
+++ b/net/ipv4/inet_hashtables.c
@@ -0,0 +1,165 @@
+/*
+ * 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.
+ *
+ *              Generic INET transport hashtables
+ *
+ * Authors:     Lotsa people, from code originally in tcp
+ *
+ *      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/config.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+
+#include <net/inet_connection_sock.h>
+#include <net/inet_hashtables.h>
+
+/*
+ * Allocate and initialize a new local port bind bucket.
+ * The bindhash mutex for snum's hash chain must be held here.
+ */
+struct inet_bind_bucket *inet_bind_bucket_create(kmem_cache_t *cachep,
+                                                 struct inet_bind_hashbucket *head,
+                                                 const unsigned short snum)
+{
+        struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, SLAB_ATOMIC);
+
+        if (tb != NULL) {
+                tb->port      = snum;
+                tb->fastreuse = 0;
+                INIT_HLIST_HEAD(&tb->owners);
+                hlist_add_head(&tb->node, &head->chain);
+        }
+        return tb;
+}
+
+EXPORT_SYMBOL(inet_bind_bucket_create);
+
+/*
+ * Caller must hold hashbucket lock for this tb with local BH disabled
+ */
+void inet_bind_bucket_destroy(kmem_cache_t *cachep, struct inet_bind_bucket *tb)
+{
+        if (hlist_empty(&tb->owners)) {
+                __hlist_del(&tb->node);
+                kmem_cache_free(cachep, tb);
+        }
+}
+
+void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
+                    const unsigned short snum)
+{
+        inet_sk(sk)->num = snum;
+        sk_add_bind_node(sk, &tb->owners);
+        inet_csk(sk)->icsk_bind_hash = tb;
+}
+
+EXPORT_SYMBOL(inet_bind_hash);
+
+/*
+ * Get rid of any references to a local port held by the given sock.
+ */
+static void __inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk)
+{
+        const int bhash = inet_bhashfn(inet_sk(sk)->num, hashinfo->bhash_size);
+        struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
+        struct inet_bind_bucket *tb;
+
+        spin_lock(&head->lock);
+        tb = inet_csk(sk)->icsk_bind_hash;
+        __sk_del_bind_node(sk);
+        inet_csk(sk)->icsk_bind_hash = NULL;
+        inet_sk(sk)->num = 0;
+        inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
+        spin_unlock(&head->lock);
+}
+
+void inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk)
+{
+        local_bh_disable();
+        __inet_put_port(hashinfo, sk);
+        local_bh_enable();
+}
+
+EXPORT_SYMBOL(inet_put_port);
+
+/*
+ * This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP.
+ * Look, when several writers sleep and reader wakes them up, all but one
+ * immediately hit write lock and grab all the cpus. Exclusive sleep solves
+ * this, _but_ remember, it adds useless work on UP machines (wake up each
+ * exclusive lock release). It should be ifdefed really.
+ */
+void inet_listen_wlock(struct inet_hashinfo *hashinfo)
+{
+        write_lock(&hashinfo->lhash_lock);
+
+        if (atomic_read(&hashinfo->lhash_users)) {
+                DEFINE_WAIT(wait);
+
+                for (;;) {
+                        prepare_to_wait_exclusive(&hashinfo->lhash_wait,
+                                                  &wait, TASK_UNINTERRUPTIBLE);
+                        if (!atomic_read(&hashinfo->lhash_users))
+                                break;
+                        write_unlock_bh(&hashinfo->lhash_lock);
+                        schedule();
+                        write_lock_bh(&hashinfo->lhash_lock);
+                }
+
+                finish_wait(&hashinfo->lhash_wait, &wait);
+        }
+}
+
+EXPORT_SYMBOL(inet_listen_wlock);
+
+/*
+ * Don't inline this cruft. Here are some nice properties to exploit here. The
+ * BSD API does not allow a listening sock to specify the remote port nor the
+ * remote address for the connection. So always assume those are both
+ * wildcarded during the search since they can never be otherwise.
+ */
+struct sock *__inet_lookup_listener(const struct hlist_head *head, const u32 daddr,
+                                    const unsigned short hnum, const int dif)
+{
+        struct sock *result = NULL, *sk;
+        const struct hlist_node *node;
+        int hiscore = -1;
+
+        sk_for_each(sk, node, head) {
+                const struct inet_sock *inet = inet_sk(sk);
+
+                if (inet->num == hnum && !ipv6_only_sock(sk)) {
+                        const __u32 rcv_saddr = inet->rcv_saddr;
+                        int score = sk->sk_family == PF_INET ? 1 : 0;
+
+                        if (rcv_saddr) {
+                                if (rcv_saddr != daddr)
+                                        continue;
+                                score += 2;
+                        }
+                        if (sk->sk_bound_dev_if) {
+                                if (sk->sk_bound_dev_if != dif)
+                                        continue;
+                                score += 2;
+                        }
+                        if (score == 5)
+                                return sk;
+                        if (score > hiscore) {
+                                hiscore = score;
+                                result  = sk;
+                        }
+                }
+        }
+        return result;
+}
+
+EXPORT_SYMBOL_GPL(__inet_lookup_listener);