sctp: simplify sctp listening code

sctp_inet_listen() call is split between UDP and TCP style.  Looking
at the code, the two functions are almost the same and can be
merged into a single helper.  This also fixes a bug that was
fixed in the UDP function, but missed in the TCP function.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 50 insertions, 102 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index bbd3cd238d7f..5fb3a8c9792e 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -5843,37 +5843,28 @@ static int sctp_get_port(struct sock *sk, unsigned short snum)
 }
 
 /*
- * 3.1.3 listen() - UDP Style Syntax
- *
- *   By default, new associations are not accepted for UDP style sockets.
- *   An application uses listen() to mark a socket as being able to
- *   accept new associations.
+ *  Move a socket to LISTENING state.
  */
-SCTP_STATIC int sctp_seqpacket_listen(struct sock *sk, int backlog)
+SCTP_STATIC int sctp_listen_start(struct sock *sk, int backlog)
 {
         struct sctp_sock *sp = sctp_sk(sk);
         struct sctp_endpoint *ep = sp->ep;
+        struct crypto_hash *tfm = NULL;
 
-        /* Only UDP style sockets that are not peeled off are allowed to
-         * listen().
-         */
-        if (!sctp_style(sk, UDP))
-                return -EINVAL;
-
-        /* If backlog is zero, disable listening. */
-        if (!backlog) {
-                if (sctp_sstate(sk, CLOSED))
-                        return 0;
-
-                sctp_unhash_endpoint(ep);
-                sk->sk_state = SCTP_SS_CLOSED;
-                return 0;
+        /* Allocate HMAC for generating cookie. */
+        if (!sctp_sk(sk)->hmac && sctp_hmac_alg) {
+                tfm = crypto_alloc_hash(sctp_hmac_alg, 0, CRYPTO_ALG_ASYNC);
+                if (IS_ERR(tfm)) {
+                        if (net_ratelimit()) {
+                                printk(KERN_INFO
+                                       "SCTP: failed to load transform for %s: %ld\n",
+                                        sctp_hmac_alg, PTR_ERR(tfm));
+                        }
+                        return -ENOSYS;
+                }
+                sctp_sk(sk)->hmac = tfm;
         }
 
-        /* Return if we are already listening. */
-        if (sctp_sstate(sk, LISTENING))
-                return 0;
-
         /*
          * If a bind() or sctp_bindx() is not called prior to a listen()
          * call that allows new associations to be accepted, the system
@@ -5884,7 +5875,6 @@ SCTP_STATIC int sctp_seqpacket_listen(struct sock *sk, int backlog)
          * extensions draft, but follows the practice as seen in TCP
          * sockets.
          *
-         * Additionally, turn off fastreuse flag since we are not listening
          */
         sk->sk_state = SCTP_SS_LISTENING;
         if (!ep->base.bind_addr.port) {
@@ -5895,113 +5885,71 @@ SCTP_STATIC int sctp_seqpacket_listen(struct sock *sk, int backlog)
                         sk->sk_state = SCTP_SS_CLOSED;
                         return -EADDRINUSE;
                 }
-                sctp_sk(sk)->bind_hash->fastreuse = 0;
         }
 
-        sctp_hash_endpoint(ep);
-        return 0;
-}
-
-/*
- * 4.1.3 listen() - TCP Style Syntax
- *
- *   Applications uses listen() to ready the SCTP endpoint for accepting
- *   inbound associations.
- */
-SCTP_STATIC int sctp_stream_listen(struct sock *sk, int backlog)
-{
-        struct sctp_sock *sp = sctp_sk(sk);
-        struct sctp_endpoint *ep = sp->ep;
-
-        /* If backlog is zero, disable listening. */
-        if (!backlog) {
-                if (sctp_sstate(sk, CLOSED))
-                        return 0;
-
-                sctp_unhash_endpoint(ep);
-                sk->sk_state = SCTP_SS_CLOSED;
-                return 0;
-        }
-
-        if (sctp_sstate(sk, LISTENING))
-                return 0;
-
-        /*
-         * If a bind() or sctp_bindx() is not called prior to a listen()
-         * call that allows new associations to be accepted, the system
-         * picks an ephemeral port and will choose an address set equivalent
-         * to binding with a wildcard address.
-         *
-         * This is not currently spelled out in the SCTP sockets
-         * extensions draft, but follows the practice as seen in TCP
-         * sockets.
-         */
-        sk->sk_state = SCTP_SS_LISTENING;
-        if (!ep->base.bind_addr.port) {
-                if (sctp_autobind(sk))
-                        return -EAGAIN;
-        } else
-                sctp_sk(sk)->bind_hash->fastreuse = 0;
-
         sk->sk_max_ack_backlog = backlog;
         sctp_hash_endpoint(ep);
         return 0;
 }
 
 /*
+ * 4.1.3 / 5.1.3 listen()
+ *
+ *   By default, new associations are not accepted for UDP style sockets.
+ *   An application uses listen() to mark a socket as being able to
+ *   accept new associations.
+ *
+ *   On TCP style sockets, applications use listen() to ready the SCTP
+ *   endpoint for accepting inbound associations.
+ *
+ *   On both types of endpoints a backlog of '0' disables listening.
+ *
  *  Move a socket to LISTENING state.
  */
 int sctp_inet_listen(struct socket *sock, int backlog)
 {
         struct sock *sk = sock->sk;
-        struct crypto_hash *tfm = NULL;
+        struct sctp_endpoint *ep = sctp_sk(sk)->ep;
         int err = -EINVAL;
 
         if (unlikely(backlog < 0))
-                goto out;
+                return err;
 
         sctp_lock_sock(sk);
 
+        /* Peeled-off sockets are not allowed to listen().  */
+        if (sctp_style(sk, UDP_HIGH_BANDWIDTH))
+                goto out;
+
         if (sock->state != SS_UNCONNECTED)
                 goto out;
 
-        /* Allocate HMAC for generating cookie. */
-        if (!sctp_sk(sk)->hmac && sctp_hmac_alg) {
-                tfm = crypto_alloc_hash(sctp_hmac_alg, 0, CRYPTO_ALG_ASYNC);
-                if (IS_ERR(tfm)) {
-                        if (net_ratelimit()) {
-                                printk(KERN_INFO
-                                       "SCTP: failed to load transform for %s: %ld\n",
-                                        sctp_hmac_alg, PTR_ERR(tfm));
-                        }
-                        err = -ENOSYS;
+        /* If backlog is zero, disable listening. */
+        if (!backlog) {
+                if (sctp_sstate(sk, CLOSED))
                         goto out;
-                }
-        }
 
-        switch (sock->type) {
-        case SOCK_SEQPACKET:
-                err = sctp_seqpacket_listen(sk, backlog);
-                break;
-        case SOCK_STREAM:
-                err = sctp_stream_listen(sk, backlog);
-                break;
-        default:
-                break;
+                err = 0;
+                sctp_unhash_endpoint(ep);
+                sk->sk_state = SCTP_SS_CLOSED;
+                if (sk->sk_reuse)
+                        sctp_sk(sk)->bind_hash->fastreuse = 1;
+                goto out;
         }
 
-        if (err)
-                goto cleanup;
+        /* If we are already listening, just update the backlog */
+        if (sctp_sstate(sk, LISTENING))
+                sk->sk_max_ack_backlog = backlog;
+        else {
+                err = sctp_listen_start(sk, backlog);
+                if (err)
+                        goto out;
+        }
 
-        /* Store away the transform reference. */
-        if (!sctp_sk(sk)->hmac)
-                sctp_sk(sk)->hmac = tfm;
+        err = 0;
 out:
         sctp_release_sock(sk);
         return err;
-cleanup:
-        crypto_free_hash(tfm);
-        goto out;
 }
 
 /*