zebra: netlink rtm tunnel msg parsing

'bridge vni add vni <id> dev <vxlan device>'
generates new RTM_NEWTUNNEL and RTM_DELTUNNEL
to add or remove vni to l3vxlan device.

Register new RTNLGRP_TUNNEL group to receive
new netlink notification.
Callback for the new RTM_xxxTUNNEL.

kernel patches:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/
linux.git/commit/?h=v5.18-rc7&id=7b8135f4df98b155b23754b6065c157861e268f1

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/
linux.git/commit/?h=v5.18-rc7&id=f9c4bb0b245cee35ef66f75bf409c9573d934cf9

Ticket:#3073812
Testing Done:

Signed-off-by: Donald Sharp <sharpd@nvidia.com>
Signed-off-by: Chirag Shah <chirag@nvidia.com>

zebra/if_netlink.c

@@ -1182,6 +1182,14 @@ int interface_lookup_netlink(struct zebra_ns *zns)
 	if (ret < 0)
 		return ret;
 
+	ret = netlink_tunneldump_read(zns);
+	if (ret < 0)
+		return ret;
+	ret = netlink_parse_info(netlink_interface, netlink_cmd, &dp_info, 0,
+				 true);
+	if (ret < 0)
+		return ret;
+
 	/* fixup linkages */
 	zebra_if_update_all_links(zns);
 	return 0;
@@ -2274,4 +2282,62 @@ uint8_t if_netlink_get_frr_protodown_r_bit(void)
 	return frr_protodown_r_bit;
 }
 
+/**
+ * netlink_request_tunneldump() - Request all tunnels from the linux kernel
+ *
+ * @zns:	Zebra namespace
+ * @family:	AF_* netlink family
+ * @type:	RTM_* (RTM_GETTUNNEL) route type
+ *
+ * Return:	Result status
+ */
+static int netlink_request_tunneldump(struct zebra_ns *zns, int family,
+				      int ifindex)
+{
+	struct {
+		struct nlmsghdr n;
+		struct tunnel_msg tmsg;
+		char buf[256];
+	} req;
+
+	/* Form the request */
+	memset(&req, 0, sizeof(req));
+	req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct tunnel_msg));
+	req.n.nlmsg_type = RTM_GETTUNNEL;
+	req.n.nlmsg_flags = NLM_F_ROOT | NLM_F_MATCH | NLM_F_REQUEST;
+	req.tmsg.family = family;
+	req.tmsg.ifindex = ifindex;
+
+	return netlink_request(&zns->netlink_cmd, &req);
+}
+
+/*
+ * Currently we only ask for vxlan l3svd vni information.
+ * In the future this can be expanded.
+ */
+int netlink_tunneldump_read(struct zebra_ns *zns)
+{
+	int ret = 0;
+	struct zebra_dplane_info dp_info;
+	struct route_node *rn;
+	struct interface *tmp_if = NULL;
+	struct zebra_if *zif;
+
+	zebra_dplane_info_from_zns(&dp_info, zns, true /*is_cmd*/);
+
+	for (rn = route_top(zns->if_table); rn; rn = route_next(rn)) {
+		tmp_if = (struct interface *)rn->info;
+		if (!tmp_if)
+			continue;
+		zif = tmp_if->info;
+		if (!zif || zif->zif_type != ZEBRA_IF_VXLAN)
+			continue;
+
+		ret = netlink_request_tunneldump(zns, PF_BRIDGE,
+						 tmp_if->ifindex);
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
 #endif /* GNU_LINUX */

zebra/if_netlink.h

@@ -50,6 +50,7 @@ extern enum netlink_msg_status
 netlink_put_address_update_msg(struct nl_batch *bth,
 			       struct zebra_dplane_ctx *ctx);
 
+extern int netlink_tunneldump_read(struct zebra_ns *zns);
 extern enum netlink_msg_status
 netlink_put_intf_update_msg(struct nl_batch *bth, struct zebra_dplane_ctx *ctx);
 

zebra/kernel_netlink.c

@@ -111,6 +111,9 @@ static const struct message nlmsg_str[] = {{RTM_NEWROUTE, "RTM_NEWROUTE"},
 					   {RTM_GETNEXTHOP, "RTM_GETNEXTHOP"},
 					   {RTM_NEWNETCONF, "RTM_NEWNETCONF"},
 					   {RTM_DELNETCONF, "RTM_DELNETCONF"},
+					   {RTM_NEWTUNNEL, "RTM_NEWTUNNEL"},
+					   {RTM_DELTUNNEL, "RTM_DELTUNNEL"},
+					   {RTM_GETTUNNEL, "RTM_GETTUNNEL"},
 					   {0}};
 
 static const struct message rtproto_str[] = {
@@ -393,8 +396,10 @@ static int netlink_information_fetch(struct nlmsghdr *h, ns_id_t ns_id,
 	case RTM_DELADDR:
 	case RTM_NEWNETCONF:
 	case RTM_DELNETCONF:
+	case RTM_NEWTUNNEL:
+	case RTM_DELTUNNEL:
+	case RTM_GETTUNNEL:
 		return 0;
-
 	default:
 		/*
 		 * If we have received this message then