sctp: support non-blocking version of the new sctp_connectx() API

Prior implementation of the new sctp_connectx() call that returns
an association ID did not work correctly on non-blocking socket.
This is because we could not return both a EINPROGRESS error and
an association id.  This is a new implementation that supports this.

Originally from Ivan Skytte Jørgensen <isj-sctp@i1.dk

Signed-off-by: Ivan Skytte Jørgensen <isj-sctp@i1.dk
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

2 files changed, 45 insertions, 1 deletions

diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index 39f5166ae7af..525864bf4f07 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -1470,6 +1470,10 @@ int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
 {
         int assoc_id;
         int error = 0;
+
+        /* If the id is already assigned, keep it. */
+        if (asoc->assoc_id)
+                return error;
 retry:
         if (unlikely(!idr_pre_get(&sctp_assocs_id, gfp)))
                 return -ENOMEM;
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 5fb3a8c9792e..7c3dfd2d9489 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1100,6 +1100,15 @@ static int __sctp_connect(struct sock* sk,
                 goto out_free;
         }
 
+        /* In case the user of sctp_connectx() wants an association
+         * id back, assign one now.
+         */
+        if (assoc_id) {
+                err = sctp_assoc_set_id(asoc, GFP_KERNEL);
+                if (err < 0)
+                        goto out_free;
+        }
+
         err = sctp_primitive_ASSOCIATE(asoc, NULL);
         if (err < 0) {
                 goto out_free;
@@ -1120,7 +1129,7 @@ static int __sctp_connect(struct sock* sk,
         timeo = sock_sndtimeo(sk, f_flags & O_NONBLOCK);
 
         err = sctp_wait_for_connect(asoc, &timeo);
-        if (!err && assoc_id)
+        if ((err == 0 || err == -EINPROGRESS) && assoc_id)
                 *assoc_id = asoc->assoc_id;
 
         /* Don't free association on exit. */
@@ -1264,6 +1273,34 @@ SCTP_STATIC int sctp_setsockopt_connectx(struct sock* sk,
                 return assoc_id;
 }
 
+/*
+ * New (hopefully final) interface for the API.  The option buffer is used
+ * both for the returned association id and the addresses.
+ */
+SCTP_STATIC int sctp_getsockopt_connectx3(struct sock* sk, int len,
+                                        char __user *optval,
+                                        int __user *optlen)
+{
+        sctp_assoc_t assoc_id = 0;
+        int err = 0;
+
+        if (len < sizeof(assoc_id))
+                return -EINVAL;
+
+        err = __sctp_setsockopt_connectx(sk,
+                        (struct sockaddr __user *)(optval + sizeof(assoc_id)),
+                        len - sizeof(assoc_id), &assoc_id);
+
+        if (err == 0 || err == -EINPROGRESS) {
+                if (copy_to_user(optval, &assoc_id, sizeof(assoc_id)))
+                        return -EFAULT;
+                if (put_user(sizeof(assoc_id), optlen))
+                        return -EFAULT;
+        }
+
+        return err;
+}
+
 /* API 3.1.4 close() - UDP Style Syntax
  * Applications use close() to perform graceful shutdown (as described in
  * Section 10.1 of [SCTP]) on ALL the associations currently represented
@@ -5578,6 +5615,9 @@ SCTP_STATIC int sctp_getsockopt(struct sock *sk, int level, int optname,
                 retval = sctp_getsockopt_local_addrs(sk, len, optval,
                                                      optlen);
                 break;
+        case SCTP_SOCKOPT_CONNECTX3:
+                retval = sctp_getsockopt_connectx3(sk, len, optval, optlen);
+                break;
         case SCTP_DEFAULT_SEND_PARAM:
                 retval = sctp_getsockopt_default_send_param(sk, len,
                                                             optval, optlen);