bgp, lib, yang: Extend route-map to support the DSCP tag

Signed-off-by: Volodymyr Huti <[email protected]>

bgpd/bgp_attr.c

@@ -1068,6 +1068,7 @@ struct attr *bgp_attr_default_set(struct attr *attr, struct bgp *bgp,
 	attr->flag |= ATTR_FLAG_BIT(BGP_ATTR_AS_PATH);
 	attr->weight = BGP_ATTR_DEFAULT_WEIGHT;
 	attr->tag = 0;
+	attr->dscp = 0;
 	attr->label_index = BGP_INVALID_LABEL_INDEX;
 	attr->label = MPLS_INVALID_LABEL;
 	attr->flag |= ATTR_FLAG_BIT(BGP_ATTR_NEXT_HOP);

bgpd/bgp_attr.h

@@ -302,6 +302,9 @@ struct attr {
 	/* SR-TE Color */
 	uint32_t srte_color;
 
+	/* DSCP tag, used by the QPPB plugin */
+	uint8_t dscp;
+
 	/* EVPN DF preference and algorithm for DF election on local ESs */
 	uint16_t df_pref;
 	uint8_t df_alg;

bgpd/bgp_route.c

@@ -16,6 +16,7 @@
 #include "stream.h"
 #include "filter.h"
 #include "log.h"
+#include "dscp.h"
 #include "routemap.h"
 #include "buffer.h"
 #include "sockunion.h"
@@ -10104,7 +10105,7 @@ void route_vty_out_detail(struct vty *vty, struct bgp *bgp, struct bgp_dest *bn,
 	json_object *json_peer = NULL;
 	json_object *json_string = NULL;
 	json_object *json_adv_to = NULL;
-	int first = 0;
+	int first = 0, dscp = attr->dscp >> 2;
 	struct listnode *node, *nnode;
 	struct peer *peer;
 	bool addpath_capable;
@@ -10776,6 +10777,18 @@ void route_vty_out_detail(struct vty *vty, struct bgp *bgp, struct bgp_dest *bn,
 		}
 	}
 
+	/* XXX: on Cisco
+	 * R1# sh ip cef 5.5.0.0 de
+	 * 5.5.0.0/24, epoch 0
+	 *     QOS: Precedence critical (5)
+	 *     recursive via ...
+	 *           nexthop ... iface
+	 */
+	if (dscp) {
+		vty_out(vty, "      QOS: Precedence %s (%d)\n",
+			dscp_enum_str(dscp), dscp);
+	}
+
 	/* Line 5 display Extended-community */
 	if (attr->flag & ATTR_FLAG_BIT(BGP_ATTR_EXT_COMMUNITIES)) {
 		if (json_paths) {

bgpd/bgp_routemap.c

@@ -107,6 +107,7 @@ o Cisco route-map
       metric-type       :  Not yet
       origin            :  Done
       tag               :  Done
+      dscp              :  Done
       weight            :  Done
       table             :  Done
 
@@ -3549,6 +3550,30 @@ static const struct route_map_rule_cmd route_set_tag_cmd = {
 	route_map_rule_tag_free,
 };
 
+/* Set dscp to object. object must be pointer to struct bgp_path_info */
+static enum route_map_cmd_result_t
+route_set_dscp(void *rule, const struct prefix *prefix, void *object)
+{
+	struct bgp_path_info *path;
+	uint8_t *rawDscp;
+
+	rawDscp = rule;
+	path = object;
+
+	/* Set dscp value */
+	path->attr->dscp = *rawDscp;
+
+	return RMAP_OKAY;
+}
+
+/* Route map commands for dscp set. */
+static const struct route_map_rule_cmd route_set_dscp_cmd = {
+	"dscp",
+	route_set_dscp,
+	route_map_rule_dscp_compile,
+	route_map_rule_dscp_free,
+};
+
 /* Set label-index to object. object must be pointer to struct bgp_path_info */
 static enum route_map_cmd_result_t
 route_set_label_index(void *rule, const struct prefix *prefix, void *object)
@@ -7796,6 +7821,9 @@ void bgp_route_map_init(void)
 	route_map_set_tag_hook(generic_set_add);
 	route_map_no_set_tag_hook(generic_set_delete);
 
+	route_map_set_dscp_hook(generic_set_add);
+	route_map_no_set_dscp_hook(generic_set_delete);
+
 	route_map_install_match(&route_match_peer_cmd);
 	route_map_install_match(&route_match_alias_cmd);
 	route_map_install_match(&route_match_local_pref_cmd);
@@ -7859,6 +7887,7 @@ void bgp_route_map_init(void)
 	route_map_install_set(&route_set_ecommunity_color_cmd);
 	route_map_install_set(&route_set_ecommunity_none_cmd);
 	route_map_install_set(&route_set_tag_cmd);
+	route_map_install_set(&route_set_dscp_cmd);
 	route_map_install_set(&route_set_label_index_cmd);
 	route_map_install_set(&route_set_l3vpn_nexthop_encapsulation_cmd);
 

bgpd/bgp_zebra.c

@@ -1254,6 +1254,7 @@ void bgp_zebra_announce(struct bgp_dest *dest, const struct prefix *p,
 	uint32_t ttl = 0;
 	uint32_t bos = 0;
 	uint32_t exp = 0;
+	uint8_t dscp;
 
 	/*
 	 * BGP is installing this route and bgp has been configured
@@ -1306,6 +1307,7 @@ void bgp_zebra_announce(struct bgp_dest *dest, const struct prefix *p,
 	}
 
 	tag = info->attr->tag;
+	dscp = info->attr->dscp;
 
 	if (peer->sort == BGP_PEER_IBGP || peer->sort == BGP_PEER_CONFED
 	    || info->sub_type == BGP_ROUTE_AGGREGATE) {
@@ -1404,11 +1406,17 @@ void bgp_zebra_announce(struct bgp_dest *dest, const struct prefix *p,
 						 p, mpinfo_cp))
 				continue;
 
-			/* metric/tag is only allowed to be
+			/* metric/tag/dscp is only allowed to be
 			 * overridden on 1st nexthop */
 			if (mpinfo == info) {
 				metric = mpinfo_cp->attr->med;
 				tag = mpinfo_cp->attr->tag;
+				/* used by hook from the QPPB plugin */
+				dscp = mpinfo_cp->attr->dscp;
+				/* expose value back to CLI `show bgp ipv4 nh`
+				 * displayed by route_vty_out_detail()`
+				 */
+				mpinfo->attr->dscp = dscp;
 			}
 		}
 

lib/routemap.c

@@ -20,6 +20,7 @@
 #include "table.h"
 #include "json.h"
 #include "jhash.h"
+#include "dscp.h"
 
 #include "lib/routemap_clippy.c"
 
@@ -446,6 +447,24 @@ void route_map_no_set_tag_hook(int (*func)(struct route_map_index *index,
 	rmap_match_set_hook.no_set_tag = func;
 }
 
+/* set dscp */
+void route_map_set_dscp_hook(int (*func)(struct route_map_index *index,
+					 const char *command, const char *arg,
+					 char *errmsg, size_t errmsg_len))
+{
+
+	rmap_match_set_hook.set_dscp = func;
+}
+
+/* no set dscp */
+void route_map_no_set_dscp_hook(int (*func)(struct route_map_index *index,
+					    const char *command,
+					    const char *arg, char *errmsg,
+					    size_t errmsg_len))
+{
+	rmap_match_set_hook.no_set_dscp = func;
+}
+
 int generic_match_add(struct route_map_index *index,
 		      const char *command, const char *arg,
 		      route_map_event_t type,
@@ -3250,6 +3269,33 @@ void *route_map_rule_tag_compile(const char *arg)
 	return tag;
 }
 
+void *route_map_rule_dscp_compile(const char *dscp)
+{
+	unsigned long ul_dscp;
+	char *pend = NULL;
+	uint8_t *shifted_dscp;
+
+	assert(dscp);
+	ul_dscp = strtoul(dscp, &pend, 0);
+	if (pend && *pend)
+		ul_dscp = dscp_decode_enum(dscp);
+
+	if (ul_dscp > (DSFIELD_DSCP >> 2)) {
+		zlog_err("Invalid dscp value: %s%s", dscp,
+			((pend && *pend) ? "" : " (numeric value must be in range 0-63)"));
+		return NULL;
+	}
+
+	shifted_dscp = XMALLOC(MTYPE_ROUTE_MAP_COMPILED, sizeof(*shifted_dscp));
+	*shifted_dscp = (ul_dscp << 2) & DSFIELD_DSCP;
+	return shifted_dscp;
+}
+
+void route_map_rule_dscp_free(void *rule)
+{
+	XFREE(MTYPE_ROUTE_MAP_COMPILED, rule);
+}
+
 void route_map_rule_tag_free(void *rule)
 {
 	XFREE(MTYPE_ROUTE_MAP_COMPILED, rule);

lib/routemap.h

@@ -317,6 +317,7 @@ DECLARE_QOBJ_TYPE(route_map);
 #define IS_SET_MIN_METRIC(A) (strmatch(A, "frr-route-map:set-min-metric"))
 #define IS_SET_MAX_METRIC(A) (strmatch(A, "frr-route-map:set-max-metric"))
 #define IS_SET_TAG(A) (strmatch(A, "frr-route-map:set-tag"))
+#define IS_SET_DSCP(A) (strmatch(A, "frr-route-map:set-dscp"))
 #define IS_SET_SR_TE_COLOR(A)                                                  \
 	(strmatch(A, "frr-route-map:set-sr-te-color"))
 /* Zebra route-map set actions */
@@ -724,8 +725,22 @@ extern void route_map_no_set_tag_hook(int (*func)(struct route_map_index *index,
 						  char *errmsg,
 						  size_t errmsg_len));
 
+/* set dscp */
+extern void route_map_set_dscp_hook(int (*func)(struct route_map_index *index,
+						const char *command,
+						const char *arg, char *errmsg,
+						size_t errmsg_len));
+/* no set dscp */
+extern void route_map_no_set_dscp_hook(
+	int (*func)(struct route_map_index *index, const char *command,
+		    const char *arg, char *errmsg, size_t errmsg_len));
+
 extern void *route_map_rule_tag_compile(const char *arg);
 extern void route_map_rule_tag_free(void *rule);
+extern uint8_t route_map_decode_dscp_enum(const char *name);
+extern const char *route_map_dscp_enum_str(int dscp);
+extern void *route_map_rule_dscp_compile(const char *dscp);
+extern void route_map_rule_dscp_free(void *dscp);
 
 /* Increment the route-map used counter */
 extern void route_map_counter_increment(struct route_map *map);
@@ -976,6 +991,14 @@ struct route_map_match_set_hooks {
 	int (*no_set_tag)(struct route_map_index *index,
 			  const char *command, const char *arg,
 			  char *errmsg, size_t errmsg_len);
+
+	/* set dscp */
+	int (*set_dscp)(struct route_map_index *index, const char *command,
+			const char *arg, char *errmsg, size_t errmsg_len);
+
+	/* no set dscp */
+	int (*no_set_dscp)(struct route_map_index *index, const char *command,
+			   const char *arg, char *errmsg, size_t errmsg_len);
 };
 
 extern struct route_map_match_set_hooks rmap_match_set_hook;

lib/routemap_cli.c

@@ -1004,6 +1004,39 @@ DEFPY_YANG(
 	return nb_cli_apply_changes(vty, NULL);
 }
 
+DEFPY_YANG(
+	set_dscp, set_dscp_cmd,
+	"set dscp DSCP$dscp",
+	SET_STR
+	"DSCP value for routing protocol\n"
+        "DSCP value\n")
+{
+	const char *xpath = "./set-action[action='frr-route-map:set-dscp']";
+	char xpath_value[XPATH_MAXLEN];
+
+	nb_cli_enqueue_change(vty, xpath, NB_OP_CREATE, NULL);
+	snprintf(xpath_value, sizeof(xpath_value), "%s/rmap-set-action/dscp",
+		 xpath);
+	nb_cli_enqueue_change(vty, xpath_value, NB_OP_MODIFY, dscp);
+
+	return nb_cli_apply_changes(vty, NULL);
+}
+
+DEFPY_YANG(
+	no_set_dscp, no_set_dscp_cmd,
+	"no set dscp [OPTVAL]",
+	NO_STR
+	SET_STR
+	"DSCP value for routing protocol\n"
+	"DSCP value\n")
+{
+	const char *xpath = "./set-action[action='frr-route-map:set-dscp']";
+
+	nb_cli_enqueue_change(vty, xpath, NB_OP_DESTROY, NULL);
+
+	return nb_cli_apply_changes(vty, NULL);
+}
+
 DEFUN_YANG (set_srte_color,
 	    set_srte_color_cmd,
 	    "set sr-te color (1-4294967295)",
@@ -1103,6 +1136,9 @@ void route_map_action_show(struct vty *vty, const struct lyd_node *dnode,
 	} else if (IS_SET_TAG(action)) {
 		vty_out(vty, " set tag %s\n",
 			yang_dnode_get_string(dnode, "./rmap-set-action/tag"));
+	} else if (IS_SET_DSCP(action)) {
+		vty_out(vty, " set dscp %s\n",
+			yang_dnode_get_string(dnode, "./rmap-set-action/dscp"));
 	} else if (IS_SET_SR_TE_COLOR(action)) {
 		vty_out(vty, " set sr-te color %s\n",
 			yang_dnode_get_string(dnode,
@@ -1669,6 +1705,9 @@ void route_map_cli_init(void)
 	install_element(RMAP_NODE, &set_tag_cmd);
 	install_element(RMAP_NODE, &no_set_tag_cmd);
 
+	install_element(RMAP_NODE, &set_dscp_cmd);
+	install_element(RMAP_NODE, &no_set_dscp_cmd);
+
 	install_element(RMAP_NODE, &set_srte_color_cmd);
 	install_element(RMAP_NODE, &no_set_srte_color_cmd);
 }

lib/routemap_northbound.c

@@ -1292,6 +1292,52 @@ lib_route_map_entry_set_action_tag_destroy(struct nb_cb_destroy_args *args)
 	return lib_route_map_entry_set_destroy(args);
 }
 
+/*
+ * XPath: /frr-route-map:lib/route-map/entry/set-action/dscp
+ */
+static int
+lib_route_map_entry_set_action_dscp_modify(struct nb_cb_modify_args *args)
+{
+	struct routemap_hook_context *rhc;
+	const char *dscp;
+	int rv;
+
+	/*
+	 * NOTE: validate if 'action' is 'dscp', currently it is not
+	 * necessary because this is the only implemented action. Other
+	 * actions might have different validations.
+	 */
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	/* Check for hook function. */
+	if (rmap_match_set_hook.set_dscp == NULL)
+		return NB_OK;
+
+	/* Add configuration. */
+	rhc = nb_running_get_entry(args->dnode, NULL, true);
+	dscp = yang_dnode_get_string(args->dnode, NULL);
+
+	/* Set destroy information. */
+	rhc->rhc_shook = rmap_match_set_hook.no_set_dscp;
+	rhc->rhc_rule = "dscp";
+
+	rv = rmap_match_set_hook.set_dscp(rhc->rhc_rmi, "dscp", dscp,
+					  args->errmsg, args->errmsg_len);
+	if (rv != CMD_SUCCESS) {
+		rhc->rhc_shook = NULL;
+		return NB_ERR_INCONSISTENCY;
+	}
+
+	return NB_OK;
+}
+
+static int
+lib_route_map_entry_set_action_dscp_destroy(struct nb_cb_destroy_args *args)
+{
+	return lib_route_map_entry_set_destroy(args);
+}
+
 /*
  * XPath: /frr-route-map:lib/route-map/entry/set-action/policy
  */
@@ -1537,6 +1583,13 @@ const struct frr_yang_module_info frr_route_map_info = {
 				.destroy = lib_route_map_entry_set_action_tag_destroy,
 			}
 		},
+		{
+			.xpath = "/frr-route-map:lib/route-map/entry/set-action/rmap-set-action/dscp",
+			.cbs = {
+				.modify = lib_route_map_entry_set_action_dscp_modify,
+				.destroy = lib_route_map_entry_set_action_dscp_destroy,
+			}
+		},
 		{
 			.xpath = "/frr-route-map:lib/route-map/entry/set-action/rmap-set-action/policy",
 			.cbs = {