bgpd: Enable BGP dynamic capability by default for datacenter profile

Dynamic capability provides more value without resetting the sessions for some
important other capabilities to exchange, like: graceful-restart, addpath, orf,
fqdn, etc.

Since we support it already, enable it by default.

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

bgpd/bgp_open.c

@@ -1975,7 +1975,7 @@ uint16_t bgp_open_capability(struct stream *s, struct peer *peer,
 	}
 
 	/* Dynamic capability. */
-	if (CHECK_FLAG(peer->flags, PEER_FLAG_DYNAMIC_CAPABILITY)) {
+	if (peergroup_flag_check(peer, PEER_FLAG_DYNAMIC_CAPABILITY)) {
 		SET_FLAG(peer->cap, PEER_CAP_DYNAMIC_ADV);
 		stream_putc(s, BGP_OPEN_OPT_CAP);
 		ext_opt_params

bgpd/bgp_vty.c

@@ -126,6 +126,10 @@ FRR_CFG_DEFAULT_BOOL(BGP_SOFT_VERSION_CAPABILITY,
 	{ .val_bool = true, .match_profile = "datacenter", },
 	{ .val_bool = false },
 );
+FRR_CFG_DEFAULT_BOOL(BGP_DYNAMIC_CAPABILITY,
+	{ .val_bool = true, .match_profile = "datacenter", },
+	{ .val_bool = false },
+);
 FRR_CFG_DEFAULT_BOOL(BGP_ENFORCE_FIRST_AS,
 	{ .val_bool = false, .match_version = "< 9.1", },
 	{ .val_bool = true },
@@ -623,6 +627,9 @@ int bgp_get_vty(struct bgp **bgp, as_t *as, const char *name,
 		if (DFLT_BGP_SOFT_VERSION_CAPABILITY)
 			SET_FLAG((*bgp)->flags,
 				 BGP_FLAG_SOFT_VERSION_CAPABILITY);
+		if (DFLT_BGP_DYNAMIC_CAPABILITY)
+			SET_FLAG((*bgp)->flags,
+				 BGP_FLAG_DYNAMIC_CAPABILITY);
 		if (DFLT_BGP_ENFORCE_FIRST_AS)
 			SET_FLAG((*bgp)->flags, BGP_FLAG_ENFORCE_FIRST_AS);
 
@@ -4298,6 +4305,24 @@ DEFPY (bgp_default_software_version_capability,
 	return CMD_SUCCESS;
 }
 
+DEFPY (bgp_default_dynamic_capability,
+       bgp_default_dynamic_capability_cmd,
+       "[no] bgp default dynamic-capability",
+       NO_STR
+       BGP_STR
+       "Configure BGP defaults\n"
+       "Advertise dynamic capability for all neighbors\n")
+{
+	VTY_DECLVAR_CONTEXT(bgp, bgp);
+
+	if (no)
+		UNSET_FLAG(bgp->flags, BGP_FLAG_DYNAMIC_CAPABILITY);
+	else
+		SET_FLAG(bgp->flags, BGP_FLAG_DYNAMIC_CAPABILITY);
+
+	return CMD_SUCCESS;
+}
+
 /* "bgp network import-check" configuration.  */
 DEFUN (bgp_network_import_check,
        bgp_network_import_check_cmd,
@@ -18383,9 +18408,15 @@ static void bgp_config_write_peer_global(struct vty *vty, struct bgp *bgp,
 		vty_out(vty, " neighbor %s timers delayopen %u\n", addr,
 			peer->bgp->default_delayopen);
 
-	/* capability dynamic */
+	/* capability software-version */
-	if (peergroup_flag_check(peer, PEER_FLAG_DYNAMIC_CAPABILITY))
+	if (CHECK_FLAG(bgp->flags, BGP_FLAG_DYNAMIC_CAPABILITY)) {
-		vty_out(vty, " neighbor %s capability dynamic\n", addr);
+		if (!peergroup_flag_check(peer, PEER_FLAG_DYNAMIC_CAPABILITY))
+			vty_out(vty, " no neighbor %s capability dynamic\n",
+				addr);
+	} else {
+		if (peergroup_flag_check(peer, PEER_FLAG_DYNAMIC_CAPABILITY))
+			vty_out(vty, " neighbor %s capability dynamic\n", addr);
+	}
 
 	/* capability extended-nexthop */
 	if (peergroup_flag_check(peer, PEER_FLAG_CAPABILITY_ENHE)) {
@@ -19076,6 +19107,15 @@ int bgp_config_write(struct vty *vty)
 					? ""
 					: "no ");
 
+		if (!!CHECK_FLAG(bgp->flags, BGP_FLAG_DYNAMIC_CAPABILITY) !=
+		    SAVE_BGP_DYNAMIC_CAPABILITY)
+			vty_out(vty,
+				" %sbgp default dynamic-capability\n",
+				CHECK_FLAG(bgp->flags,
+					   BGP_FLAG_DYNAMIC_CAPABILITY)
+					? ""
+					: "no ");
+
 		/* BGP default subgroup-pkt-queue-max. */
 		if (bgp->default_subgroup_pkt_queue_max
 		    != BGP_DEFAULT_SUBGROUP_PKT_QUEUE_MAX)
@@ -20124,6 +20164,9 @@ void bgp_vty_init(void)
 	/* bgp default software-version-capability */
 	install_element(BGP_NODE, &bgp_default_software_version_capability_cmd);
 
+	/* bgp default dynamic-capability */
+	install_element(BGP_NODE, &bgp_default_dynamic_capability_cmd);
+
 	/* "bgp default subgroup-pkt-queue-max" commands. */
 	install_element(BGP_NODE, &bgp_default_subgroup_pkt_queue_max_cmd);
 	install_element(BGP_NODE, &no_bgp_default_subgroup_pkt_queue_max_cmd);

bgpd/bgpd.c

@@ -1544,6 +1544,9 @@ struct peer *peer_new(struct bgp *bgp)
 	if (CHECK_FLAG(bgp->flags, BGP_FLAG_SOFT_VERSION_CAPABILITY))
 		SET_FLAG(peer->flags, PEER_FLAG_CAPABILITY_SOFT_VERSION);
 
+	if (CHECK_FLAG(bgp->flags, BGP_FLAG_DYNAMIC_CAPABILITY))
+		SET_FLAG(peer->flags, PEER_FLAG_DYNAMIC_CAPABILITY);
+
 	SET_FLAG(peer->flags_invert, PEER_FLAG_CAPABILITY_FQDN);
 	SET_FLAG(peer->flags, PEER_FLAG_CAPABILITY_FQDN);
 
@@ -2919,6 +2922,13 @@ static void peer_group2peer_config_copy(struct peer_group *group,
 			SET_FLAG(peer->flags,
 				 PEER_FLAG_CAPABILITY_SOFT_VERSION);
 
+	/* capability dynamic apply */
+	if (!CHECK_FLAG(peer->flags_override,
+			PEER_FLAG_DYNAMIC_CAPABILITY))
+		if (CHECK_FLAG(conf->flags, PEER_FLAG_DYNAMIC_CAPABILITY))
+			SET_FLAG(peer->flags,
+				 PEER_FLAG_DYNAMIC_CAPABILITY);
+
 	/* password apply */
 	if (!CHECK_FLAG(peer->flags_override, PEER_FLAG_PASSWORD))
 		PEER_STR_ATTR_INHERIT(peer, group, password,

bgpd/bgpd.h

@@ -522,6 +522,7 @@ struct bgp {
 #define BGP_FLAG_LU_IPV6_EXPLICIT_NULL (1ULL << 34)
 #define BGP_FLAG_SOFT_VERSION_CAPABILITY (1ULL << 35)
 #define BGP_FLAG_ENFORCE_FIRST_AS (1ULL << 36)
+#define BGP_FLAG_DYNAMIC_CAPABILITY (1ULL << 37)
 
 	/* BGP default address-families.
 	 * New peers inherit enabled afi/safis from bgp instance.

doc/user/bgp.rst

@@ -1816,7 +1816,7 @@ Configuring Peers
    This includes changing graceful-restart (LLGR also) timers,
    enabling/disabling add-path, and other supported capabilities.
 
-.. clicmd:: neighbor PEER capability fqdn 
+.. clicmd:: neighbor PEER capability fqdn
 
    Allow BGP to negotiate the FQDN Capability with its peers.
 
@@ -1825,7 +1825,7 @@ Configuring Peers
 
    This capability is activated by default. The ``no neighbor PEER capability
    fqdn`` avoid negotiation of that capability. This is useful for peers who
-   are not supporting this capability or supporting BGP Capabilities 
+   are not supporting this capability or supporting BGP Capabilities
    Negotiation RFC 2842.
 
 .. clicmd:: neighbor <A.B.C.D|X:X::X:X|WORD> accept-own
@@ -1949,6 +1949,13 @@ Configuring Peers
    outputs. It's easier to troubleshoot if you have a number of BGP peers
    and a number of routes to check.
 
+.. clicmd:: bgp default dynamic-capability
+
+   This command enables dynamic capability advertisement by default
+   for all the neighbors.
+
+   For ``datacenter`` profile, this is enabled by default.
+
 .. clicmd:: bgp default software-version-capability
 
    This command enables software version capability advertisement by default
@@ -3219,7 +3226,7 @@ that the 2001:db8:2:2:: prefix is valid.
 
 .. code-block:: frr
 
-   r1# show bgp nexthop detail 
+   r1# show bgp nexthop detail
    Current BGP nexthop cache:
     2001:db8:2:2:: valid [IGP metric 0], #paths 4
      gate 2001:db8:12::2, if eth0