staticd: Accept full blackhole typed keywords for ip_route_cmd

Before this patch we allow entering next-hop interface address as any string.

Like, we can type: `ip route 10.10.10.10/32 bla`, but this will create a blackhole
route instead of using an interface `bla`.

The same is with reject.

After the patch:

```
$ vtysh -c 'con' -c 'ip route 10.10.10.100/32 bla'
ERROR: SET_CONFIG request failed, Error: nexthop interface name must be (reject, blackhole)

$ ip link show dev bla
472: bla: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN mode DEFAULT group default qlen 1000
    link/ether fa:45:bd:f1:f8:f0 brd ff:ff:ff:ff:ff:ff

$ vtysh -c 'sh run | include ip route'
$ vtysh -c 'con' -c 'ip route 10.10.10.100/32 blac'
$ vtysh -c 'sh run | include ip route'
ip route 10.10.10.100/32 blackhole

$ vtysh -c 'con' -c 'no ip route 10.10.10.100/32 blac'
$ vtysh -c 'sh run | include ip route'
$ vtysh -c 'con' -c 'ip route 10.10.10.100/32 blackhole'
$ vtysh -c 'sh run | include ip route'
ip route 10.10.10.100/32 blackhole

$ vtysh -c 'con' -c 'no ip route 10.10.10.100/32 blackhole'
$ vtysh -c 'sh run | include ip route'
$ vtysh -c 'con' -c 'ip route 10.10.10.100/32 Null0'
$ vtysh -c 'sh run | include ip route'
ip route 10.10.10.100/32 Null0

$ vtysh -c 'con' -c 'no ip route 10.10.10.100/32 Null0'
$ vtysh -c 'sh run | include ip route'
$
```

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>

staticd/static_nb_config.c

@@ -135,7 +135,8 @@ static bool static_nexthop_create(struct nb_cb_create_args *args)
 	switch (args->event) {
 	case NB_EV_VALIDATE:
 		ifname = yang_dnode_get_string(args->dnode, "./interface");
-		if (ifname != NULL) {
+		nh_type = yang_dnode_get_enum(args->dnode, "./nh-type");
+		if (ifname != NULL && nh_type != STATIC_BLACKHOLE) {
 			if (strcasecmp(ifname, "Null0") == 0
 			    || strcasecmp(ifname, "reject") == 0
 			    || strcasecmp(ifname, "blackhole") == 0) {
@@ -371,10 +372,26 @@ static int static_nexthop_bh_type_modify(struct nb_cb_modify_args *args)
 {
 	struct static_nexthop *nh;
 	enum static_nh_type nh_type;
+	const char *nh_ifname;
+	const char *nh_vrf;
 
 	switch (args->event) {
 	case NB_EV_VALIDATE:
 		nh_type = yang_dnode_get_enum(args->dnode, "../nh-type");
+		nh_ifname = yang_dnode_get_string(args->dnode, "../interface");
+		nh_vrf = yang_dnode_get_string(args->dnode, "../vrf");
+		if (nh_ifname && nh_vrf) {
+			struct vrf *vrf = vrf_lookup_by_name(nh_vrf);
+			struct interface *ifp = if_lookup_by_name(nh_ifname,
+								  vrf->vrf_id);
+
+			if (ifp && (!strmatch(nh_ifname, "blackhole") ||
+				    !strmatch(nh_ifname, "reject"))) {
+				snprintf(args->errmsg, args->errmsg_len,
+					 "nexthop interface name must be (reject, blackhole)");
+				return NB_ERR_VALIDATION;
+			}
+		}
 		if (nh_type != STATIC_BLACKHOLE) {
 			snprintf(args->errmsg, args->errmsg_len,
 				 "nexthop type is not the blackhole type");

staticd/static_vty.c

@@ -58,6 +58,8 @@ struct static_route_args {
 	bool bfd_multi_hop;
 	const char *bfd_source;
 	const char *bfd_profile;
+
+	const char *input;
 };
 
 static int static_route_nb_run(struct vty *vty, struct static_route_args *args)
@@ -145,9 +147,20 @@ static int static_route_nb_run(struct vty *vty, struct static_route_args *args)
 	else
 		buf_gate_str = "";
 
-	if (args->gateway == NULL && args->interface_name == NULL)
+	if (args->gateway == NULL && args->interface_name == NULL) {
 		type = STATIC_BLACKHOLE;
-	else if (args->gateway && args->interface_name) {
+		/* If this is blackhole/reject flagged route, then
+		 * specify interface_name with the value of what was really
+		 * entered.
+		 * interface_name will be validated later in NB functions
+		 * to check if we don't create blackhole/reject routes that
+		 * match the real interface names.
+		 * E.g.: `ip route 10.0.0.1/32 bla` will create a blackhole
+		 * route despite the real interface named `bla` exists.
+		 */
+		if (args->input)
+			args->interface_name = args->input;
+	} else if (args->gateway && args->interface_name) {
 		if (args->afi == AFI_IP)
 			type = STATIC_IPV4_GATEWAY_IFNAME;
 		else
@@ -499,6 +512,8 @@ DEFPY_YANG(ip_route_blackhole,
       "Table to configure\n"
       "The table number to configure\n")
 {
+	int idx_flag = 0;
+
 	struct static_route_args args = {
 		.delete = !!no,
 		.afi = AFI_IP,
@@ -513,6 +528,9 @@ DEFPY_YANG(ip_route_blackhole,
 		.vrf = vrf,
 	};
 
+	if (flag && argv_find(argv, argc, flag, &idx_flag))
+		args.input = argv[idx_flag]->arg;
+
 	return static_route_nb_run(vty, &args);
 }
 
@@ -541,6 +559,8 @@ DEFPY_YANG(ip_route_blackhole_vrf,
       "Table to configure\n"
       "The table number to configure\n")
 {
+	int idx_flag = 0;
+
 	struct static_route_args args = {
 		.delete = !!no,
 		.afi = AFI_IP,
@@ -562,6 +582,9 @@ DEFPY_YANG(ip_route_blackhole_vrf,
 	 */
 	assert(args.prefix);
 
+	if (flag && argv_find(argv, argc, flag, &idx_flag))
+		args.input = argv[idx_flag]->arg;
+
 	return static_route_nb_run(vty, &args);
 }
 
@@ -852,6 +875,8 @@ DEFPY_YANG(ipv6_route_blackhole,
       "Table to configure\n"
       "The table number to configure\n")
 {
+	int idx_flag = 0;
+
 	struct static_route_args args = {
 		.delete = !!no,
 		.afi = AFI_IP6,
@@ -866,6 +891,9 @@ DEFPY_YANG(ipv6_route_blackhole,
 		.vrf = vrf,
 	};
 
+	if (flag && argv_find(argv, argc, flag, &idx_flag))
+		args.input = argv[idx_flag]->arg;
+
 	return static_route_nb_run(vty, &args);
 }
 
@@ -894,6 +922,8 @@ DEFPY_YANG(ipv6_route_blackhole_vrf,
       "Table to configure\n"
       "The table number to configure\n")
 {
+	int idx_flag = 0;
+
 	struct static_route_args args = {
 		.delete = !!no,
 		.afi = AFI_IP6,
@@ -915,6 +945,9 @@ DEFPY_YANG(ipv6_route_blackhole_vrf,
 	 */
 	assert(args.prefix);
 
+	if (flag && argv_find(argv, argc, flag, &idx_flag))
+		args.input = argv[idx_flag]->arg;
+
 	return static_route_nb_run(vty, &args);
 }