sctp: clean up __sctp_connect

__sctp_connect is doing quit similar things as sctp_sendmsg_new_asoc.
To factor out common functions, this patch is to clean up their code
to make them look more similar:

  1. create the asoc and add a peer with the 1st addr.
  2. add peers with the other addrs into this asoc one by one.

while at it, also remove the unused 'addrcnt'.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/socket.c

@@ -1049,152 +1049,104 @@ static int sctp_setsockopt_bindx(struct sock *sk,
  * Common routine for handling connect() and sctp_connectx().
  * Connect will come in with just a single address.
  */
-static int __sctp_connect(struct sock *sk,
-			  struct sockaddr *kaddrs,
-			  int addrs_size, int flags,
-			  sctp_assoc_t *assoc_id)
+static int __sctp_connect(struct sock *sk, struct sockaddr *kaddrs,
+			  int addrs_size, int flags, sctp_assoc_t *assoc_id)
 {
-	struct net *net = sock_net(sk);
-	struct sctp_sock *sp;
-	struct sctp_endpoint *ep;
-	struct sctp_association *asoc = NULL;
-	struct sctp_association *asoc2;
+	struct sctp_association *old, *asoc;
+	struct sctp_sock *sp = sctp_sk(sk);
+	struct sctp_endpoint *ep = sp->ep;
 	struct sctp_transport *transport;
-	union sctp_addr to;
+	struct net *net = sock_net(sk);
+	void *addr_buf = kaddrs;
+	union sctp_addr *daddr;
 	enum sctp_scope scope;
+	struct sctp_af *af;
+	int walk_size, err;
 	long timeo;
-	int err = 0;
-	int addrcnt = 0;
-	int walk_size = 0;
-	union sctp_addr *sa_addr = NULL;
-	void *addr_buf;
-	unsigned short port;
 
-	sp = sctp_sk(sk);
-	ep = sp->ep;
-
-	/* connect() cannot be done on a socket that is already in ESTABLISHED
-	 * state - UDP-style peeled off socket or a TCP-style socket that
-	 * is already connected.
-	 * It cannot be done even on a TCP-style listening socket.
-	 */
 	if (sctp_sstate(sk, ESTABLISHED) || sctp_sstate(sk, CLOSING) ||
-	    (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))) {
-		err = -EISCONN;
-		goto out_free;
-	}
+	    (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)))
+		return -EISCONN;
 
-	/* Walk through the addrs buffer and count the number of addresses. */
-	addr_buf = kaddrs;
-	while (walk_size < addrs_size) {
-		struct sctp_af *af;
+	daddr = addr_buf;
+	af = sctp_get_af_specific(daddr->sa.sa_family);
+	if (!af || af->sockaddr_len > addrs_size)
+		return -EINVAL;
 
-		if (walk_size + sizeof(sa_family_t) > addrs_size) {
-			err = -EINVAL;
-			goto out_free;
-		}
+	err = sctp_verify_addr(sk, daddr, af->sockaddr_len);
+	if (err)
+		return err;
 
-		sa_addr = addr_buf;
-		af = sctp_get_af_specific(sa_addr->sa.sa_family);
+	asoc = sctp_endpoint_lookup_assoc(ep, daddr, &transport);
+	if (asoc)
+		return asoc->state >= SCTP_STATE_ESTABLISHED ? -EISCONN
+							     : -EALREADY;
 
-		/* If the address family is not supported or if this address
-		 * causes the address buffer to overflow return EINVAL.
-		 */
-		if (!af || (walk_size + af->sockaddr_len) > addrs_size) {
-			err = -EINVAL;
-			goto out_free;
-		}
+	if (sctp_endpoint_is_peeled_off(ep, daddr))
+		return -EADDRNOTAVAIL;
 
-		port = ntohs(sa_addr->v4.sin_port);
+	if (!ep->base.bind_addr.port) {
+		if (sctp_autobind(sk))
+			return -EAGAIN;
+	} else {
+		if (ep->base.bind_addr.port < inet_prot_sock(net) &&
+		    !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE))
+			return -EACCES;
+	}
 
-		/* Save current address so we can work with it */
-		memcpy(&to, sa_addr, af->sockaddr_len);
+	scope = sctp_scope(daddr);
+	asoc = sctp_association_new(ep, sk, scope, GFP_KERNEL);
+	if (!asoc)
+		return -ENOMEM;
 
-		err = sctp_verify_addr(sk, &to, af->sockaddr_len);
-		if (err)
+	err = sctp_assoc_set_bind_addr_from_ep(asoc, scope, GFP_KERNEL);
+	if (err < 0)
 		goto out_free;
 
-		/* Make sure the destination port is correctly set
-		 * in all addresses.
-		 */
-		if (asoc && asoc->peer.port && asoc->peer.port != port) {
-			err = -EINVAL;
+	transport = sctp_assoc_add_peer(asoc, daddr, GFP_KERNEL, SCTP_UNKNOWN);
+	if (!transport) {
+		err = -ENOMEM;
 		goto out_free;
 	}
 
-		/* Check if there already is a matching association on the
-		 * endpoint (other than the one created here).
-		 */
-		asoc2 = sctp_endpoint_lookup_assoc(ep, &to, &transport);
-		if (asoc2 && asoc2 != asoc) {
-			if (asoc2->state >= SCTP_STATE_ESTABLISHED)
-				err = -EISCONN;
-			else
-				err = -EALREADY;
+	addr_buf += af->sockaddr_len;
+	walk_size = af->sockaddr_len;
+	while (walk_size < addrs_size) {
+		err = -EINVAL;
+		if (walk_size + sizeof(sa_family_t) > addrs_size)
 			goto out_free;
-		}
 
-		/* If we could not find a matching association on the endpoint,
-		 * make sure that there is no peeled-off association matching
-		 * the peer address even on another socket.
-		 */
-		if (sctp_endpoint_is_peeled_off(ep, &to)) {
-			err = -EADDRNOTAVAIL;
+		daddr = addr_buf;
+		af = sctp_get_af_specific(daddr->sa.sa_family);
+		if (!af || af->sockaddr_len + walk_size > addrs_size)
 			goto out_free;
-		}
 
-		if (!asoc) {
-			/* If a bind() or sctp_bindx() is not called prior to
-			 * an sctp_connectx() call, the system picks an
-			 * ephemeral port and will choose an address set
-			 * equivalent to binding with a wildcard address.
-			 */
-			if (!ep->base.bind_addr.port) {
-				if (sctp_autobind(sk)) {
-					err = -EAGAIN;
-					goto out_free;
-				}
-			} else {
-				/*
-				 * If an unprivileged user inherits a 1-many
-				 * style socket with open associations on a
-				 * privileged port, it MAY be permitted to
-				 * accept new associations, but it SHOULD NOT
-				 * be permitted to open new associations.
-				 */
-				if (ep->base.bind_addr.port <
-				    inet_prot_sock(net) &&
-				    !ns_capable(net->user_ns,
-				    CAP_NET_BIND_SERVICE)) {
-					err = -EACCES;
+		if (asoc->peer.port != ntohs(daddr->v4.sin_port))
 			goto out_free;
-				}
-			}
 
-			scope = sctp_scope(&to);
-			asoc = sctp_association_new(ep, sk, scope, GFP_KERNEL);
-			if (!asoc) {
-				err = -ENOMEM;
+		err = sctp_verify_addr(sk, daddr, af->sockaddr_len);
+		if (err)
 			goto out_free;
-			}
 
-			err = sctp_assoc_set_bind_addr_from_ep(asoc, scope,
-							      GFP_KERNEL);
-			if (err < 0) {
+		old = sctp_endpoint_lookup_assoc(ep, daddr, &transport);
+		if (old && old != asoc) {
+			err = old->state >= SCTP_STATE_ESTABLISHED ? -EISCONN
+								   : -EALREADY;
 			goto out_free;
 		}
 
+		if (sctp_endpoint_is_peeled_off(ep, daddr)) {
+			err = -EADDRNOTAVAIL;
+			goto out_free;
 		}
 
-		/* Prime the peer's transport structures.  */
-		transport = sctp_assoc_add_peer(asoc, &to, GFP_KERNEL,
+		transport = sctp_assoc_add_peer(asoc, daddr, GFP_KERNEL,
 						SCTP_UNKNOWN);
 		if (!transport) {
 			err = -ENOMEM;
 			goto out_free;
 		}
 
-		addrcnt++;
 		addr_buf  += af->sockaddr_len;
 		walk_size += af->sockaddr_len;
 	}
@@ -1209,39 +1161,24 @@ static int __sctp_connect(struct sock *sk,
 	}
 
 	err = sctp_primitive_ASSOCIATE(net, asoc, NULL);
-	if (err < 0) {
+	if (err < 0)
 		goto out_free;
-	}
 
 	/* Initialize sk's dport and daddr for getpeername() */
 	inet_sk(sk)->inet_dport = htons(asoc->peer.port);
-	sp->pf->to_sk_daddr(sa_addr, sk);
+	sp->pf->to_sk_daddr(daddr, sk);
 	sk->sk_err = 0;
 
-	timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
-
 	if (assoc_id)
 		*assoc_id = asoc->assoc_id;
 
-	err = sctp_wait_for_connect(asoc, &timeo);
-	/* Note: the asoc may be freed after the return of
-	 * sctp_wait_for_connect.
-	 */
-
-	/* Don't free association on exit. */
-	asoc = NULL;
+	timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
+	return sctp_wait_for_connect(asoc, &timeo);
 
 out_free:
 	pr_debug("%s: took out_free path with asoc:%p kaddrs:%p err:%d\n",
 		 __func__, asoc, kaddrs, err);
-
-	if (asoc) {
-		/* sctp_primitive_ASSOCIATE may have added this association
-		 * To the hash table, try to unhash it, just in case, its a noop
-		 * if it wasn't hashed so we're safe
-		 */
 	sctp_association_free(asoc);
-	}
 	return err;
 }