bgpd: Create `set distance XXX` command for routemaps

Allow bgp to set a local Administrative distance to use
for installing routes into the rib.

Example:
!
router bgp 9323
 bgp router-id 1.2.3.4
 neighbor enp0s8 interface remote-as external
 !
 address-family ipv4 unicast
  neighbor enp0s8 route-map DISTANCE in
 exit-address-family
!
route-map DISTANCE permit 10
 set distance 153
!
line vty
!
end
eva# show ip route
Codes: K - kernel route, C - connected, S - static, R - RIP,
       O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
       T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
       F - PBR, f - OpenFabric,
       > - selected route, * - FIB route, q - queued route, r - rejected route

B   0.0.0.0/0 [153/0] via fe80::a00:27ff:fe84:c2d6, enp0s8, 00:00:06
K>* 0.0.0.0/0 [0/100] via 10.0.2.2, enp0s3, 00:06:31
B>* 1.1.1.1/32 [153/0] via fe80::a00:27ff:fe84:c2d6, enp0s8, 00:00:06
B>* 1.1.1.2/32 [153/0] via fe80::a00:27ff:fe84:c2d6, enp0s8, 00:00:06
B>* 1.1.1.3/32 [153/0] via fe80::a00:27ff:fe84:c2d6, enp0s8, 00:00:06
C>* 10.0.2.0/24 is directly connected, enp0s3, 00:06:31
K>* 169.254.0.0/16 [0/1000] is directly connected, enp0s3, 00:06:31
eva#

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

4 files changed, 59 insertions, 3 deletions

diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index ab9dc3092..db12098de 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -519,8 +519,7 @@ unsigned int attrhash_key_make(const void *p)
 	MIX(attr->mp_nexthop_len);
 	key = jhash(attr->mp_nexthop_global.s6_addr, IPV6_MAX_BYTELEN, key);
 	key = jhash(attr->mp_nexthop_local.s6_addr, IPV6_MAX_BYTELEN, key);
-	MIX(attr->nh_ifindex);
-	MIX(attr->nh_lla_ifindex);
+	MIX3(attr->nh_ifindex, attr->nh_lla_ifindex, attr->distance);
 
 	return key;
 }
@@ -562,7 +561,8 @@ bool attrhash_cmp(const void *p1, const void *p2)
 				      &attr2->originator_id)
 		    && overlay_index_same(attr1, attr2)
 		    && attr1->nh_ifindex == attr2->nh_ifindex
-		    && attr1->nh_lla_ifindex == attr2->nh_lla_ifindex)
+		    && attr1->nh_lla_ifindex == attr2->nh_lla_ifindex
+		    && attr1->distance == attr2->distance)
 			return true;
 	}
 
diff --git a/bgpd/bgp_attr.h b/bgpd/bgp_attr.h
index f1a871fe4..cfa428a79 100644
--- a/bgpd/bgp_attr.h
+++ b/bgpd/bgp_attr.h
@@ -206,6 +206,9 @@ struct attr {
 
 	/* EVPN local router-mac */
 	struct ethaddr rmac;
+
+	/* Distance as applied by Route map */
+	uint8_t distance;
 };
 
 /* rmap_change_flags definition */
diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index 962f0b337..05974bb2b 100644
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -11877,6 +11877,9 @@ uint8_t bgp_distance_apply(struct prefix *p, struct bgp_path_info *pinfo,
 
 	peer = pinfo->peer;
 
+	if (pinfo->attr->distance)
+		return pinfo->attr->distance;
+
 	/* Check source address. */
 	sockunion2hostprefix(&peer->su, &q);
 	rn = bgp_node_match(bgp_distance_table[afi][safi], &q);
diff --git a/bgpd/bgp_routemap.c b/bgpd/bgp_routemap.c
index da702ec85..55b6e670b 100644
--- a/bgpd/bgp_routemap.c
+++ b/bgpd/bgp_routemap.c
@@ -1683,6 +1683,30 @@ struct route_map_rule_cmd route_set_weight_cmd = {
 	"weight", route_set_weight, route_value_compile, route_value_free,
 };
 
+/* `set distance DISTANCE */
+static enum route_map_cmd_result_t
+route_set_distance(void *rule, const struct prefix *prefix,
+		   route_map_object_t type, void *object)
+{
+	struct bgp_path_info *path = object;
+	struct rmap_value *rv = rule;
+
+	if (type != RMAP_BGP)
+		return RMAP_OKAY;
+
+	path->attr->distance = rv->value;
+
+	return RMAP_OKAY;
+}
+
+/* set distance rule structure */
+struct route_map_rule_cmd route_set_distance_cmd = {
+	"distance",
+	route_set_distance,
+	route_value_compile,
+	route_value_free,
+};
+
 /* `set metric METRIC' */
 
 /* Set metric to attribute. */
@@ -4064,6 +4088,29 @@ DEFUN (set_ip_nexthop_unchanged,
 		    "unchanged");
 }
 
+DEFUN (set_distance,
+       set_distance_cmd,
+       "set distance (0-255)",
+       SET_STR
+       "BGP Administrative Distance to use\n"
+       "Distance value\n")
+{
+	int idx_number = 2;
+
+	return generic_set_add(vty, VTY_GET_CONTEXT(route_map_index),
+			       "distance", argv[idx_number]->arg);
+}
+
+DEFUN (no_set_distance,
+       no_set_distance_cmd,
+       "no set distance [(0-255)]",
+       NO_STR SET_STR
+       "BGP Administrative Distance to use\n"
+       "Distance value\n")
+{
+	return generic_set_delete(vty, VTY_GET_CONTEXT(route_map_index),
+				  "distance", NULL);
+}
 
 DEFUN (set_local_pref,
        set_local_pref_cmd,
@@ -5119,6 +5166,7 @@ void bgp_route_map_init(void)
 	route_map_install_set(&route_set_weight_cmd);
 	route_map_install_set(&route_set_label_index_cmd);
 	route_map_install_set(&route_set_metric_cmd);
+	route_map_install_set(&route_set_distance_cmd);
 	route_map_install_set(&route_set_aspath_prepend_cmd);
 	route_map_install_set(&route_set_aspath_exclude_cmd);
 	route_map_install_set(&route_set_origin_cmd);
@@ -5172,6 +5220,8 @@ void bgp_route_map_init(void)
 	install_element(RMAP_NODE, &set_ip_nexthop_peer_cmd);
 	install_element(RMAP_NODE, &set_ip_nexthop_unchanged_cmd);
 	install_element(RMAP_NODE, &set_local_pref_cmd);
+	install_element(RMAP_NODE, &set_distance_cmd);
+	install_element(RMAP_NODE, &no_set_distance_cmd);
 	install_element(RMAP_NODE, &no_set_local_pref_cmd);
 	install_element(RMAP_NODE, &set_weight_cmd);
 	install_element(RMAP_NODE, &set_label_index_cmd);