net: Split dump_links into part

We'll need to dump links for another purpose, so prepare the
generic rtnl talker for that.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

net.c

@@ -109,7 +109,7 @@ static int dump_one_link(struct nlmsghdr *hdr, void *arg)
 	return ret;
 }
 
-static int dump_links(struct cr_fdset *fds)
+static int do_dump_links(int (*cb)(struct nlmsghdr *h, void *), void *arg)
 {
 	int sk, ret;
 	struct {
@@ -117,8 +117,6 @@ static int dump_links(struct cr_fdset *fds)
 		struct rtgenmsg g;
 	} req;
 
-	pr_info("Dumping netns links\n");
-
 	ret = sk = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
 	if (sk < 0) {
 		pr_perror("Can't open rtnl sock for net dump");
@@ -133,12 +131,19 @@ static int dump_links(struct cr_fdset *fds)
 	req.nlh.nlmsg_seq = CR_NLMSG_SEQ;
 	req.g.rtgen_family = AF_PACKET;
 
-	ret = do_rtnl_req(sk, &req, sizeof(req), dump_one_link, fds);
+	ret = do_rtnl_req(sk, &req, sizeof(req), cb, arg);
 	close(sk);
 out:
 	return ret;
 }
 
+static int dump_links(struct cr_fdset *fds)
+{
+	pr_info("Dumping netns links\n");
+
+	return do_dump_links(dump_one_link, fds);
+}
+
 static int restore_link_cb(struct nlmsghdr *hdr, void *arg)
 {
 	pr_info("Got responce on SETLINK =)\n");