link: Support for IFLA_AF_SPEC

This feature isn't upstream yet. It's required to test a patch in
my local tree.

Makes the link parser understand IFLA_AF_SPEC and call the address
family specific parser.

include/linux/if_link.h

@@ -80,6 +80,24 @@ struct rtnl_link_ifmap {
 	__u8	port;
 };
 
+/*
+ * IFLA_AF_SPEC
+ *   Contains nested attributes for address family specific attributes.
+ *   Each address family may create a attribute with the address family
+ *   number as type and create its own attribute structure in it.
+ *
+ *   Example:
+ *   [IFLA_AF_SPEC] = {
+ *       [AF_INET6] = {
+ *           [IFLA_INET6_FLAGS] = ...,
+ *           [IFLA_INET6_CONF] = ...,
+ *       },
+ *       [AF_BRIDGE] = {
+ *           [IFLA_BRIDGE_PORT] = ...
+ *       }
+ *   }
+ */
+
 enum {
 	IFLA_UNSPEC,
 	IFLA_ADDRESS,
@@ -116,6 +134,7 @@ enum {
 	IFLA_STATS64,
 	IFLA_VF_PORTS,
 	IFLA_PORT_SELF,
+	IFLA_AF_SPEC,
 	__IFLA_MAX
 };
 

include/netlink/route/link/api.h

@@ -105,6 +105,11 @@ struct rtnl_link_af_ops
 	int		      (*ao_parse_protinfo)(struct rtnl_link *,
 						   struct nlattr *, void *);
 
+	/** Called if a IFLA_AF_SPEC attribute needs to be parsed. Typically
+	 * stores the parsed data in the address family specific buffer. */
+	int		      (*ao_parse_af)(struct rtnl_link *,
+					     struct nlattr *, void *);
+
 	/** Dump address family specific link attributes */
 	void		      (*ao_dump[NL_DUMP_MAX+1])(struct rtnl_link *,
 							struct nl_dump_params *,

lib/route/link.c

@@ -183,6 +183,26 @@ static struct nl_cache_ops rtnl_link_ops;
 static struct nl_object_ops link_obj_ops;
 /** @endcond */
 
+static struct rtnl_link_af_ops *af_lookup_and_alloc(struct rtnl_link *link,
+						    int family)
+{
+	struct rtnl_link_af_ops *af_ops;
+
+	af_ops = rtnl_link_af_ops_lookup(family);
+	if (!af_ops)
+		return NULL;
+
+	if (!link->l_af_data[family] && af_ops->ao_alloc) {
+		link->l_af_data[family] = af_ops->ao_alloc(link);
+		if (!link->l_af_data[family]) {
+			rtnl_link_af_ops_put(af_ops);
+			return NULL;
+		}
+	}
+
+	return af_ops;
+}
+
 static int af_free(struct rtnl_link *link, struct rtnl_link_af_ops *ops,
 		    void *data, void *arg)
 {
@@ -339,6 +359,7 @@ static struct nla_policy link_policy[IFLA_MAX+1] = {
 	[IFLA_MAP]	= { .minlen = sizeof(struct rtnl_link_ifmap) },
 	[IFLA_IFALIAS]	= { .type = NLA_STRING, .maxlen = IFALIASZ },
 	[IFLA_NUM_VF]	= { .type = NLA_U32 },
+	[IFLA_AF_SPEC]	= { .type = NLA_NESTED },
 };
 
 static struct nla_policy link_info_policy[IFLA_INFO_MAX+1] = {
@@ -377,15 +398,7 @@ static int link_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who,
 			  LINK_ATTR_ARPTYPE| LINK_ATTR_IFINDEX |
 			  LINK_ATTR_FLAGS | LINK_ATTR_CHANGE);
 
-	if ((af_ops = rtnl_link_af_ops_lookup(family))) {
-		if (af_ops->ao_alloc) {
-			link->l_af_data[family] = af_ops->ao_alloc(link);
-			if (!link->l_af_data[family]) {
-				err = -NLE_NOMEM;
-				goto errout;
-			}
-		}
-
+	if ((af_ops = af_lookup_and_alloc(link, family))) {
 		if (af_ops->ao_protinfo_policy) {
 			memcpy(&link_policy[IFLA_PROTINFO],
 			       af_ops->ao_protinfo_policy,
@@ -588,6 +601,26 @@ static int link_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who,
 			goto errout;
 	}
 
+	if (tb[IFLA_AF_SPEC]) {
+		struct nlattr *af_attr;
+		int remaining;
+
+		nla_for_each_nested(af_attr, tb[IFLA_AF_SPEC], remaining) {
+			af_ops = af_lookup_and_alloc(link, nla_type(af_attr));
+			if (af_ops && af_ops->ao_parse_af) {
+				char *af_data = link->l_af_data[nla_type(af_attr)];
+
+				err = af_ops->ao_parse_af(link, af_attr, af_data);
+
+				rtnl_link_af_ops_put(af_ops);
+
+				if (err < 0)
+					goto errout;
+			}
+
+		}
+	}
+
 	err = pp->pp_cb((struct nl_object *) link, pp);
 errout:
 	rtnl_link_af_ops_put(af_ops);

lib/route/link/inet6.c

@@ -311,6 +311,7 @@ static struct rtnl_link_af_ops inet6_ops = {
 	.ao_clone			= &inet6_clone,
 	.ao_free			= &inet6_free,
 	.ao_parse_protinfo		= &inet6_parse_protinfo,
+	.ao_parse_af			= &inet6_parse_protinfo,
 	.ao_dump[NL_DUMP_DETAILS]	= &inet6_dump_details,
 	.ao_dump[NL_DUMP_STATS]		= &inet6_dump_stats,
 	.ao_protinfo_policy		= &protinfo_policy,