sctp: implement socket option SCTP_GET_ASSOC_ID_LIST

This patch Implement socket option SCTP_GET_ASSOC_ID_LIST.
SCTP Socket API Extension:

  8.2.6. Get the Current Identifiers of Associations
         (SCTP_GET_ASSOC_ID_LIST)

  This option gets the current list of SCTP association identifiers of
  the SCTP associations handled by a one-to-many style socket.

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

2 files changed, 65 insertions, 0 deletions

diff --git a/include/net/sctp/user.h b/include/net/sctp/user.h
index e73ebdae323d..793617ecbfdf 100644
--- a/include/net/sctp/user.h
+++ b/include/net/sctp/user.h
@@ -91,6 +91,7 @@ typedef __s32 sctp_assoc_t;
 #define SCTP_PEER_AUTH_CHUNKS   26      /* Read only */
 #define SCTP_LOCAL_AUTH_CHUNKS  27      /* Read only */
 #define SCTP_GET_ASSOC_NUMBER   28      /* Read only */
+#define SCTP_GET_ASSOC_ID_LIST  29      /* Read only */
 
 /* Internal Socket Options. Some of the sctp library functions are
  * implemented using these socket options.
@@ -669,6 +670,18 @@ struct sctp_authchunks {
 };
 
 /*
+ * 8.2.6. Get the Current Identifiers of Associations
+ *        (SCTP_GET_ASSOC_ID_LIST)
+ *
+ * This option gets the current list of SCTP association identifiers of
+ * the SCTP associations handled by a one-to-many style socket.
+ */
+struct sctp_assoc_ids {
+        __u32           gaids_number_of_ids;
+        sctp_assoc_t    gaids_assoc_id[];
+};
+
+/*
  * 8.3, 8.5 get all peer/local addresses in an association.
  * This parameter struct is used by SCTP_GET_PEER_ADDRS and 
  * SCTP_GET_LOCAL_ADDRS socket options used internally to implement
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 431b8905c570..f694ee116746 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -5277,6 +5277,55 @@ static int sctp_getsockopt_assoc_number(struct sock *sk, int len,
         return 0;
 }
 
+/*
+ * 8.2.6. Get the Current Identifiers of Associations
+ *        (SCTP_GET_ASSOC_ID_LIST)
+ *
+ * This option gets the current list of SCTP association identifiers of
+ * the SCTP associations handled by a one-to-many style socket.
+ */
+static int sctp_getsockopt_assoc_ids(struct sock *sk, int len,
+                                    char __user *optval, int __user *optlen)
+{
+        struct sctp_sock *sp = sctp_sk(sk);
+        struct sctp_association *asoc;
+        struct sctp_assoc_ids *ids;
+        u32 num = 0;
+
+        if (sctp_style(sk, TCP))
+                return -EOPNOTSUPP;
+
+        if (len < sizeof(struct sctp_assoc_ids))
+                return -EINVAL;
+
+        list_for_each_entry(asoc, &(sp->ep->asocs), asocs) {
+                num++;
+        }
+
+        if (len < sizeof(struct sctp_assoc_ids) + sizeof(sctp_assoc_t) * num)
+                return -EINVAL;
+
+        len = sizeof(struct sctp_assoc_ids) + sizeof(sctp_assoc_t) * num;
+
+        ids = kmalloc(len, GFP_KERNEL);
+        if (unlikely(!ids))
+                return -ENOMEM;
+
+        ids->gaids_number_of_ids = num;
+        num = 0;
+        list_for_each_entry(asoc, &(sp->ep->asocs), asocs) {
+                ids->gaids_assoc_id[num++] = asoc->assoc_id;
+        }
+
+        if (put_user(len, optlen) || copy_to_user(optval, ids, len)) {
+                kfree(ids);
+                return -EFAULT;
+        }
+
+        kfree(ids);
+        return 0;
+}
+
 SCTP_STATIC int sctp_getsockopt(struct sock *sk, int level, int optname,
                                 char __user *optval, int __user *optlen)
 {
@@ -5409,6 +5458,9 @@ SCTP_STATIC int sctp_getsockopt(struct sock *sk, int level, int optname,
         case SCTP_GET_ASSOC_NUMBER:
                 retval = sctp_getsockopt_assoc_number(sk, len, optval, optlen);
                 break;
+        case SCTP_GET_ASSOC_ID_LIST:
+                retval = sctp_getsockopt_assoc_ids(sk, len, optval, optlen);
+                break;
         default:
                 retval = -ENOPROTOOPT;
                 break;