Support for rtnl_link_add()

API for adding virtual links

diff --git a/lib/route/link.c b/lib/route/link.c
index 3c5b219525ecc42e8a81181359624d591e510161..9dfa5e1b6499ee997f849cb7fbb8e33170230dd4 100644 (file)
--- a/lib/route/link.c
+++ b/lib/route/link.c
@@ -303,7 +303,8 @@ static void release_link_info(struct rtnl_link *link)
        struct rtnl_link_info_ops *io = link->l_info_ops;
 
        if (io != NULL) {
-               io->io_free(link);
+               if (io->io_free)
+                       io->io_free(link);
                rtnl_link_info_ops_put(io);
                link->l_info_ops = NULL;
        }
@@ -599,7 +600,7 @@ static int link_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who,
 
                        kind = nla_get_string(li[IFLA_INFO_KIND]);
                        ops = rtnl_link_info_ops_lookup(kind);
-                       if (ops != NULL) {
+                       if (ops && ops->io_parse) {
                                link->l_info_ops = ops;
                                err = ops->io_parse(link, li[IFLA_INFO_DATA],
                                                    li[IFLA_INFO_XSTATS]);
@@ -1071,8 +1072,7 @@ static int build_link_msg(int cmd, struct ifinfomsg *hdr,
        if (link->ce_mask & LINK_ATTR_IFALIAS)
                NLA_PUT_STRING(msg, IFLA_IFALIAS, link->l_ifalias);
 
-       if ((link->ce_mask & LINK_ATTR_LINKINFO) && link->l_info_ops &&
-           link->l_info_ops->io_put_attrs) {
+       if ((link->ce_mask & LINK_ATTR_LINKINFO) && link->l_info_ops) {
                struct nlattr *info;
 
                if (!(info = nla_nest_start(msg, IFLA_LINKINFO)))
@@ -1080,7 +1080,8 @@ static int build_link_msg(int cmd, struct ifinfomsg *hdr,
 
                NLA_PUT_STRING(msg, IFLA_INFO_KIND, link->l_info_ops->io_name);
 
-               if (link->l_info_ops->io_put_attrs(msg, link) < 0)
+               if (link->l_info_ops->io_put_attrs &&
+                   link->l_info_ops->io_put_attrs(msg, link) < 0)
                        goto nla_put_failure;
 
                nla_nest_end(msg, info);
@@ -1102,6 +1103,71 @@ nla_put_failure:
        return -NLE_MSGSIZE;
 }
 
+/**
+ * Build a netlink message requesting the addition of a new virtual link
+ * @arg link           new link to add
+ * @arg flags          additional netlink message flags
+ * @arg result         pointer to store resulting netlink message
+ *
+ * The behaviour of this function is identical to rtnl_link_add() with
+ * the exception that it will not send the message but return it in the
+ * provided return pointer instead.
+ *
+ * @see rtnl_link_add()
+ *
+ * @note This operation is not supported on all kernel versions.
+ *
+ * @return 0 on success or a negative error code.
+ */
+int rtnl_link_build_add_request(struct rtnl_link *link, int flags,
+                               struct nl_msg **result)
+{
+       struct ifinfomsg ifi = {
+               .ifi_family = link->l_family,
+               .ifi_index = link->l_index,
+               .ifi_flags = link->l_flags,
+       };
+
+       return build_link_msg(RTM_NEWLINK, &ifi, link, flags, result);
+}
+
+/**
+ * Add virtual link
+ * @arg sk             netlink socket.
+ * @arg link           new link to add
+ * @arg flags          additional netlink message flags
+ *
+ * Builds a \c RTM_NEWLINK netlink message requesting the addition of
+ * a new virtual link.
+ *
+ * After sending, the function will wait for the ACK or an eventual
+ * error message to be received and will therefore block until the
+ * operation has been completed.
+ *
+ * @note Disabling auto-ack (nl_socket_disable_auto_ack()) will cause
+ *       this function to return immediately after sending. In this case,
+ *       it is the responsibility of the caller to handle any error
+ *       messages returned.
+ *
+ * @return 0 on success or a negative error code.
+ */
+int rtnl_link_add(struct nl_sock *sk, struct rtnl_link *link, int flags)
+{
+       struct nl_msg *msg;
+       int err;
+       
+       err = rtnl_link_build_add_request(link, flags, &msg);
+       if (err < 0)
+               return err;
+
+       err = nl_send_auto_complete(sk, msg);
+       nlmsg_free(msg);
+       if (err < 0)
+               return err;
+
+       return wait_for_ack(sk);
+}
+
 /**
  * Build a netlink message requesting the modification of a link
  * @arg orig           original link to change
@@ -1928,9 +1994,10 @@ int rtnl_link_set_info_type(struct rtnl_link *link, const char *type)
        if (link->l_info_ops)
                release_link_info(link);
 
-       if ((err = io->io_alloc(link)) < 0)
+       if (io->io_alloc && (err = io->io_alloc(link)) < 0)
                return err;
 
+       link->ce_mask |= LINK_ATTR_LINKINFO;
        link->l_info_ops = io;
 
        return 0;