Merge pull request #14140 from opensourcerouting/fix/handle_more_capabilities_via_dynamic_capability

bgpd: Handle software version capability dynamicaly

bgpd/bgp_packet.c

@@ -1199,6 +1199,8 @@ void bgp_capability_send(struct peer *peer, afi_t afi, safi_t safi,
 	struct stream *s;
 	iana_afi_t pkt_afi = IANA_AFI_IPV4;
 	iana_safi_t pkt_safi = IANA_SAFI_UNICAST;
+	unsigned long cap_len;
+	uint16_t len;
 
 	/* Convert AFI, SAFI to values for packet. */
 	bgp_map_afi_safi_int2iana(afi, safi, &pkt_afi, &pkt_safi);
@@ -1209,7 +1211,41 @@ void bgp_capability_send(struct peer *peer, afi_t afi, safi_t safi,
 	bgp_packet_set_marker(s, BGP_MSG_CAPABILITY);
 
 	/* Encode MP_EXT capability. */
-	if (capability_code == CAPABILITY_CODE_MP) {
+	switch (capability_code) {
+	case CAPABILITY_CODE_SOFT_VERSION:
+		SET_FLAG(peer->cap, PEER_CAP_SOFT_VERSION_ADV);
+		stream_putc(s, action);
+		stream_putc(s, CAPABILITY_CODE_SOFT_VERSION);
+		cap_len = stream_get_endp(s);
+		stream_putc(s, 0); /* Capability Length */
+
+		/* The Capability Length SHOULD be no greater than 64.
+		 * This is the limit to allow other capabilities as much
+		 * space as they require.
+		 */
+		const char *soft_version = cmd_software_version_get();
+
+		len = strlen(soft_version);
+		if (len > BGP_MAX_SOFT_VERSION)
+			len = BGP_MAX_SOFT_VERSION;
+
+		stream_putc(s, len);
+		stream_put(s, soft_version, len);
+
+		/* Software Version capability Len. */
+		len = stream_get_endp(s) - cap_len - 1;
+		stream_putc_at(s, cap_len, len);
+
+		if (bgp_debug_neighbor_events(peer))
+			zlog_debug("%pBP sending CAPABILITY has %s Software Version for afi/safi: %s/%s",
+				   peer,
+				   action == CAPABILITY_ACTION_SET
+					   ? "Advertising"
+					   : "Removing",
+				   iana_afi2str(pkt_afi),
+				   iana_safi2str(pkt_safi));
+		break;
+	case CAPABILITY_CODE_MP:
 		stream_putc(s, action);
 		stream_putc(s, CAPABILITY_CODE_MP);
 		stream_putc(s, CAPABILITY_CODE_MP_LEN);
@@ -1224,6 +1260,22 @@ void bgp_capability_send(struct peer *peer, afi_t afi, safi_t safi,
 				action == CAPABILITY_ACTION_SET ? "Advertising"
 								: "Removing",
 				iana_afi2str(pkt_afi), iana_safi2str(pkt_safi));
+		break;
+	case CAPABILITY_CODE_REFRESH:
+	case CAPABILITY_CODE_ORF:
+	case CAPABILITY_CODE_RESTART:
+	case CAPABILITY_CODE_AS4:
+	case CAPABILITY_CODE_DYNAMIC:
+	case CAPABILITY_CODE_ADDPATH:
+	case CAPABILITY_CODE_ENHANCED_RR:
+	case CAPABILITY_CODE_LLGR:
+	case CAPABILITY_CODE_FQDN:
+	case CAPABILITY_CODE_ENHE:
+	case CAPABILITY_CODE_EXT_MESSAGE:
+	case CAPABILITY_CODE_ROLE:
+		break;
+	default:
+		break;
 	}
 
 	/* Set packet size. */
@@ -2698,6 +2750,7 @@ static int bgp_capability_msg_parse(struct peer *peer, uint8_t *pnt,
 	afi_t afi;
 	iana_safi_t pkt_safi;
 	safi_t safi;
+	char soft_version[BGP_MAX_SOFT_VERSION + 1] = {};
 
 	end = pnt + length;
 
@@ -2728,14 +2781,6 @@ static int bgp_capability_msg_parse(struct peer *peer, uint8_t *pnt,
 				"%s CAPABILITY has action: %d, code: %u, length %u",
 				peer->host, action, hdr->code, hdr->length);
 
-		if (hdr->length < sizeof(struct capability_mp_data)) {
-			zlog_info(
-				"%pBP Capability structure is not properly filled out, expected at least %zu bytes but header length specified is %d",
-				peer, sizeof(struct capability_mp_data),
-				hdr->length);
-			return BGP_Stop;
-		}
-
 		/* Capability length check. */
 		if ((pnt + hdr->length + 3) > end) {
 			zlog_info("%s Capability length error", peer->host);
@@ -2744,20 +2789,42 @@ static int bgp_capability_msg_parse(struct peer *peer, uint8_t *pnt,
 			return BGP_Stop;
 		}
 
-		/* Fetch structure to the byte stream. */
+		/* Ignore capability when override-capability is set. */
-		memcpy(&mpc, pnt + 3, sizeof(struct capability_mp_data));
+		if (CHECK_FLAG(peer->flags, PEER_FLAG_OVERRIDE_CAPABILITY))
-		pnt += hdr->length + 3;
+			continue;
 
-		/* We know MP Capability Code. */
+		switch (hdr->code) {
-		if (hdr->code == CAPABILITY_CODE_MP) {
+		case CAPABILITY_CODE_SOFT_VERSION:
+			if (action == CAPABILITY_ACTION_SET) {
+				SET_FLAG(peer->cap, PEER_CAP_SOFT_VERSION_RCV);
+
+				memcpy(&soft_version, pnt + 3, hdr->length);
+				soft_version[hdr->length] = '\0';
+
+				XFREE(MTYPE_BGP_SOFT_VERSION,
+				      peer->soft_version);
+				peer->soft_version =
+					XSTRDUP(MTYPE_BGP_SOFT_VERSION,
+						soft_version);
+			} else {
+				UNSET_FLAG(peer->cap, PEER_CAP_SOFT_VERSION_RCV);
+				XFREE(MTYPE_BGP_SOFT_VERSION,
+				      peer->soft_version);
+			}
+			break;
+		case CAPABILITY_CODE_MP:
+			if (hdr->length < sizeof(struct capability_mp_data)) {
+				zlog_info("%pBP Capability structure is not properly filled out, expected at least %zu bytes but header length specified is %d",
+					  peer,
+					  sizeof(struct capability_mp_data),
+					  hdr->length);
+				return BGP_Stop;
+			}
+
+			memcpy(&mpc, pnt + 3, sizeof(struct capability_mp_data));
 			pkt_afi = ntohs(mpc.afi);
 			pkt_safi = mpc.safi;
 
-			/* Ignore capability when override-capability is set. */
-			if (CHECK_FLAG(peer->flags,
-				       PEER_FLAG_OVERRIDE_CAPABILITY))
-				continue;
-
 			/* Convert AFI, SAFI to internal values. */
 			if (bgp_map_afi_safi_iana2int(pkt_afi, pkt_safi, &afi,
 						      &safi)) {
@@ -2797,12 +2864,29 @@ static int bgp_capability_msg_parse(struct peer *peer, uint8_t *pnt,
 				else
 					return BGP_Stop;
 			}
-		} else {
+			break;
+		case CAPABILITY_CODE_REFRESH:
+		case CAPABILITY_CODE_ORF:
+		case CAPABILITY_CODE_RESTART:
+		case CAPABILITY_CODE_AS4:
+		case CAPABILITY_CODE_DYNAMIC:
+		case CAPABILITY_CODE_ADDPATH:
+		case CAPABILITY_CODE_ENHANCED_RR:
+		case CAPABILITY_CODE_LLGR:
+		case CAPABILITY_CODE_FQDN:
+		case CAPABILITY_CODE_ENHE:
+		case CAPABILITY_CODE_EXT_MESSAGE:
+		case CAPABILITY_CODE_ROLE:
+			break;
+		default:
 			flog_warn(
 				EC_BGP_UNRECOGNIZED_CAPABILITY,
 				"%s unrecognized capability code: %d - ignored",
 				peer->host, hdr->code);
+			break;
 		}
+
+		pnt += hdr->length + 3;
 	}
 
 	/* No FSM action necessary */

bgpd/bgp_vty.c

@@ -5725,17 +5725,29 @@ DEFPY(neighbor_capability_software_version,
       "Advertise Software Version capability to the peer\n")
 {
 	struct peer *peer;
+	int ret;
 
 	peer = peer_and_group_lookup_vty(vty, neighbor);
-	if (peer && peer->conf_if)
+	if (!peer)
-		return CMD_SUCCESS;
+		return CMD_WARNING_CONFIG_FAILED;
 
 	if (no)
-		return peer_flag_unset_vty(vty, neighbor,
+		ret = peer_flag_unset_vty(vty, neighbor,
 					  PEER_FLAG_CAPABILITY_SOFT_VERSION);
 	else
-		return peer_flag_set_vty(vty, neighbor,
+		ret = peer_flag_set_vty(vty, neighbor,
 					PEER_FLAG_CAPABILITY_SOFT_VERSION);
+
+	if (peer_established(peer)) {
+		if (CHECK_FLAG(peer->cap, PEER_CAP_DYNAMIC_RCV) &&
+		    CHECK_FLAG(peer->cap, PEER_CAP_DYNAMIC_ADV))
+			bgp_capability_send(peer, AFI_IP, SAFI_UNICAST,
+					    CAPABILITY_CODE_SOFT_VERSION,
+					    no ? CAPABILITY_ACTION_UNSET
+					       : CAPABILITY_ACTION_SET);
+	}
+
+	return ret;
 }
 
 static int peer_af_flag_modify_vty(struct vty *vty, const char *peer_str,

bgpd/bgpd.c

@@ -4449,7 +4449,7 @@ static const struct peer_flag_action peer_flag_action_list[] = {
 	{PEER_FLAG_PORT, 0, peer_change_reset},
 	{PEER_FLAG_AIGP, 0, peer_change_none},
 	{PEER_FLAG_GRACEFUL_SHUTDOWN, 0, peer_change_none},
-	{PEER_FLAG_CAPABILITY_SOFT_VERSION, 0, peer_change_reset},
+	{PEER_FLAG_CAPABILITY_SOFT_VERSION, 0, peer_change_none},
 	{0, 0, 0}};
 
 static const struct peer_flag_action peer_af_flag_action_list[] = {

tests/topotests/bgp_dynamic_capability/r1/bgpd.conf

@@ -0,0 +1,10 @@
+!
+!debug bgp neighbor
+!
+router bgp 65001
+ no bgp ebgp-requires-policy
+ neighbor 192.168.1.2 remote-as external
+ neighbor 192.168.1.2 timers 1 3
+ neighbor 192.168.1.2 timers connect 1
+ neighbor 192.168.1.2 capability dynamic
+!

tests/topotests/bgp_dynamic_capability/r1/zebra.conf

@@ -0,0 +1,4 @@
+!
+int r1-eth0
+ ip address 192.168.1.1/24
+!

tests/topotests/bgp_dynamic_capability/r2/bgpd.conf

@@ -0,0 +1,10 @@
+!
+!debug bgp neighbor
+!
+router bgp 65002
+ no bgp ebgp-requires-policy
+ neighbor 192.168.1.1 remote-as external
+ neighbor 192.168.1.1 timers 1 3
+ neighbor 192.168.1.1 timers connect 1
+ neighbor 192.168.1.1 capability dynamic
+!

tests/topotests/bgp_dynamic_capability/r2/zebra.conf

@@ -0,0 +1,4 @@
+!
+int r2-eth0
+ ip address 192.168.1.2/24
+!

tests/topotests/bgp_dynamic_capability/test_bgp_dynamic_capability_software_version.py

@@ -0,0 +1,153 @@
+#!/usr/bin/env python
+# SPDX-License-Identifier: ISC
+
+# Copyright (c) 2023 by
+# Donatas Abraitis <donatas@opensourcerouting.org>
+#
+
+"""
+Test if software version capability is exchanged dynamically.
+"""
+
+import os
+import re
+import sys
+import json
+import pytest
+import functools
+
+pytestmark = pytest.mark.bgpd
+
+CWD = os.path.dirname(os.path.realpath(__file__))
+sys.path.append(os.path.join(CWD, "../"))
+
+# pylint: disable=C0413
+from lib import topotest
+from lib.topogen import Topogen, TopoRouter, get_topogen
+from lib.common_config import step
+
+pytestmark = [pytest.mark.bgpd]
+
+
+def setup_module(mod):
+    topodef = {"s1": ("r1", "r2")}
+    tgen = Topogen(topodef, mod.__name__)
+    tgen.start_topology()
+
+    router_list = tgen.routers()
+
+    for i, (rname, router) in enumerate(router_list.items(), 1):
+        router.load_config(
+            TopoRouter.RD_ZEBRA, os.path.join(CWD, "{}/zebra.conf".format(rname))
+        )
+        router.load_config(
+            TopoRouter.RD_BGP, os.path.join(CWD, "{}/bgpd.conf".format(rname))
+        )
+
+    tgen.start_router()
+
+
+def teardown_module(mod):
+    tgen = get_topogen()
+    tgen.stop_topology()
+
+
+def test_bgp_dynamic_capability():
+    tgen = get_topogen()
+
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    r1 = tgen.gears["r1"]
+    r2 = tgen.gears["r2"]
+
+    def _bgp_converge():
+        output = json.loads(r1.vtysh_cmd("show bgp neighbor json"))
+        expected = {
+            "192.168.1.2": {
+                "bgpState": "Established",
+                "neighborCapabilities": {
+                    "dynamic": "advertisedAndReceived",
+                    "softwareVersion": {
+                        "advertisedSoftwareVersion": None,
+                        "receivedSoftwareVersion": None,
+                    },
+                },
+                "connectionsEstablished": 1,
+                "connectionsDropped": 0,
+            }
+        }
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(
+        _bgp_converge,
+    )
+    _, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert result is None, "Can't converge"
+
+    step("Enable software version capability and check if it's exchanged dynamically")
+
+    r1.vtysh_cmd(
+        """
+    configure terminal
+    router bgp
+      neighbor 192.168.1.2 capability software-version
+    """
+    )
+
+    r2.vtysh_cmd(
+        """
+    configure terminal
+    router bgp
+      neighbor 192.168.1.1 capability software-version
+    """
+    )
+
+    def _bgp_check_if_session_not_reset():
+        def _bgp_software_version():
+            try:
+                versions = output["192.168.1.2"]["neighborCapabilities"][
+                    "softwareVersion"
+                ]
+                adv = versions["advertisedSoftwareVersion"]
+                rcv = versions["receivedSoftwareVersion"]
+
+                if not adv and not rcv:
+                    return ""
+
+                pattern = "FRRouting/\\d.+"
+                if re.search(pattern, adv) and re.search(pattern, rcv):
+                    return adv, rcv
+            except:
+                return ""
+
+        output = json.loads(r1.vtysh_cmd("show bgp neighbor json"))
+        adv, rcv = _bgp_software_version()
+        expected = {
+            "192.168.1.2": {
+                "bgpState": "Established",
+                "neighborCapabilities": {
+                    "dynamic": "advertisedAndReceived",
+                    "softwareVersion": {
+                        "advertisedSoftwareVersion": adv,
+                        "receivedSoftwareVersion": rcv,
+                    },
+                },
+                "connectionsEstablished": 1,
+                "connectionsDropped": 0,
+            }
+        }
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(
+        _bgp_check_if_session_not_reset,
+    )
+    _, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert (
+        result is None
+    ), "Session was reset after enabling software version capability"
+
+
+if __name__ == "__main__":
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))