From c2a8376e2988bf32e84ead5632b7cdef0087970f Mon Sep 17 00:00:00 2001 From: zhou-run Date: Thu, 24 Oct 2024 11:09:37 +0800 Subject: [PATCH] isisd: When the ISIS types of the routers do not match on a P2P link, the neighbor status remains UP Test Scenario: RouterA and RouterB are in the same routing domain and have configured a P2P link. RouterA is configured with "is-type level-1" while RouterB is configured with "is-type level-1-2". They establish a level-1 UP neighborship. In this scenario, we expect that when RouterB's configuration is switched to "is-type level-2-only", the neighborship status on both RouterA and RouterB would be non-UP. However, RouterB still shows the neighbor as UP. Upon receiving a P2P Hello packet, the function "process_p2p_hello" is invoked. According to the ISO/IEC 10589 protocol specification, section 8.2.5.2 a) and tables 5 and 7, if the "iih->circ_type" of the neighbor's hello packet does not match one's own "circuit->is_type," we may choose to take no action. When establishing a neighborship for the first time, the neighbor's status can remain in the "Initializing" state. However, if the neighborship has already been established and one's own "circuit->is_type" changes, the neighbor's UP status cannot be reset. Therefore, when processing P2P Hello packets, we should be cognizant of changes in our own link adjacency type. Topotest has identified a core issue during testing. (gdb) bt "#0 0xb7efe579 in __kernel_vsyscall () \#1 0xb79f62f7 in ?? () \#2 0xbf981dd0 in ?? () \#3 \#4 0xb79f7722 in ?? () \#5 0xb7ed8634 in _DYNAMIC () from /home/z15467/isis_core/usr/lib/i386-linux-gnu/frr/libfrr.so.0.0.0 \#6 0x0001003c in ?? () \#7 0x00010000 in ?? () \#8 0xb7df3322 in _frr_mtx_lock (mutex=) at ../lib/frr_pthread.h:255 \#9 event_timer_remain_msec (thread=0x10000) at ../lib/event.c:734 \#10 event_timer_remain_msec (thread=) at ../lib/event.c:727 \#11 0x004fb4aa in _send_hello_sched (circuit=, threadp=0x2189de0, level=1, delay=) at ../isisd/isis_pdu.c:2116 \#12 0x004e8dbc in isis_circuit_up (circuit=) at ../isisd/isis_circuit.c:734 \#13 0x004ea8f7 in isis_csm_state_change (event=, circuit=, arg=) at ../isisd/isis_csm.c:98 \#14 0x004ea23f in isis_circuit_circ_type_set (circuit=, circ_type=) at ../isisd/isis_circuit.c:1578 \#15 0x0053aefa in lib_interface_isis_network_type_modify (args=) at ../isisd/isis_nb_config.c:4190 \#16 0xb7dbcc8d in nb_callback_modify (errmsg_len=8192, errmsg=0xbf982afc "", resource=0x2186220, dnode=, event=NB_EV_APPLY, nb_node=0x1fafe70, context=) at ../lib/northbound.c:1550 \#17 nb_callback_configuration (context=, event=NB_EV_APPLY, change=, errmsg=, errmsg_len=) at ../lib/northbound.c:1900 \#18 0xb7dbd646 in nb_transaction_process (errmsg_len=, errmsg=, transaction=, event=) at ../lib/northbound.c:2028 \#19 nb_candidate_commit_apply (transaction=, save_transaction=, transaction_id=, errmsg=, errmsg_len=) at ../lib/northbound.c:1368 \#20 0xb7dbdd68 in nb_candidate_commit (context=..., candidate=, save_transaction=, comment=, transaction_id=, errmsg=, errmsg_len=) at ../lib/northbound.c:1401 \#21 0xb7dc0cff in nb_cli_classic_commit (vty=vty@entry=0x21d6940) at ../lib/northbound_cli.c:57 \#22 0xb7dc0f46 in nb_cli_apply_changes_internal (vty=vty@entry=0x21d6940, xpath_base=xpath_base@entry=0xbf986b7c "/frr-interface:lib/interface[name='r5-eth0']", clear_pending=clear_pending@entry=false) at ../lib/northbound_cli.c:184 \#23 0xb7dc130b in nb_cli_apply_changes (vty=, xpath_base_fmt=) at ../lib/northbound_cli.c:240 \#24 0x00542c1d in isis_network_magic (self=, argc=, argv=, no=, vty=) at ../isisd/isis_cli.c:3101 \#25 isis_network (self=, vty=, argc=, argv=) at ./isisd/isis_cli_clippy.c:5499 \#26 0xb7d6d8f1 in cmd_execute_command_real (vline=vline@entry=0x219afa0, vty=vty@entry=0x21d6940, cmd=cmd@entry=0x0, up_level=) at ../lib/command.c:1003 \#27 0xb7d6d9e0 in cmd_execute_command (vline=, vty=, cmd=, vtysh=) at ../lib/command.c:1061 \#28 0xb7d6dc60 in cmd_execute (vty=, cmd=, matched=, vtysh=) at ../lib/command.c:1228 \#29 0xb7dfb58a in vty_command (vty=vty@entry=0x21d6940, buf=0x21e0ff0 ' ' , "isis network point-to-point") at ../lib/vty.c:625 \#30 0xb7dfc560 in vty_execute (vty=vty@entry=0x21d6940) at ../lib/vty.c:1388 \#31 0xb7dfdc8d in vtysh_read (thread=) at ../lib/vty.c:2400 \#32 0xb7df4d47 in event_call (thread=) at ../lib/event.c:2019 \#33 0xb7d9a831 in frr_run (master=) at ../lib/libfrr.c:1232 \#34 0x004e4758 in main (argc=7, argv=0xbf989a24, envp=0xbf989a44) at ../isisd/isis_main.c:354 (gdb) f 9 \#9 event_timer_remain_msec (thread=0x10000) at ../lib/event.c:734 734 ../lib/event.c: No such file or directory. (gdb) p pthread No symbol "pthread" in current context. (gdb) p thread $1 = (struct event *) 0x10000 When LAN links and P2P links share the` circuit->u` of a neighbor, if one link is no longer in use and the union is not cleared, the other link is unable to pass the non-empty check, resulting in accessing an invalid pointer. Unfortunately, for non-DIS devices in LAN links, `circuit->u.bc.run_dr_elect[x]` is essentially always 1, but in `isis_circuit_down()`,` circuit->u.bc.run_dr_elect[x] `will not be cleared because `circuit->u.bc.is_dr[x]` is always 0. Consequently, when switching to a P2P link, `isis_circuit_circ_type_set()` does not reset the link in a non-C_STATE_UP state, leading to subsequent accesses of `circuit->u.p2p.t_send_p2p_hello` resulting in a non-empty yet invalid address. I believe that in `isis_circuit_down()`, the LAN link should unconditionally clear `circuit->u.bc.run_dr_elect[x]`. Signed-off-by: zhou-run --- isisd/isis_pdu.c | 3 +- tests/topotests/isis_topo1/test_isis_topo1.py | 161 ++++++++++++++++++ 2 files changed, 163 insertions(+), 1 deletion(-) diff --git a/isisd/isis_pdu.c b/isisd/isis_pdu.c index 23238d314a20..c2ada459eb1c 100644 --- a/isisd/isis_pdu.c +++ b/isisd/isis_pdu.c @@ -231,7 +231,8 @@ static int process_p2p_hello(struct iih_info *iih) return ISIS_OK; } } - if (!adj || adj->level != iih->calculated_type) { + if (!adj || adj->level != iih->calculated_type || + !(iih->circuit->is_type & iih->circ_type)) { if (!adj) { adj = isis_new_adj(iih->sys_id, NULL, iih->calculated_type, iih->circuit); diff --git a/tests/topotests/isis_topo1/test_isis_topo1.py b/tests/topotests/isis_topo1/test_isis_topo1.py index fe3d8655657b..e02fb07dafe2 100644 --- a/tests/topotests/isis_topo1/test_isis_topo1.py +++ b/tests/topotests/isis_topo1/test_isis_topo1.py @@ -12,6 +12,7 @@ """ test_isis_topo1.py: Test ISIS topology. """ +import time import datetime import functools import json @@ -314,6 +315,107 @@ def test_isis_neighbor_json(): ), assertmsg +def test_isis_neighbor_state(): + "Check that the neighbor states remain normal when the ISIS type is switched." + + tgen = get_topogen() + # Don't run this test if we have any failure. + if tgen.routers_have_failure(): + pytest.skip(tgen.errors) + + logger.info("Checking 'show isis neighbor state on a p2p link'") + + # Establish a P2P link + # When the IS-IS type of r3 is set to level-1-2 and the IS-IS type of r5 is set to level-1, + # it is expected that all neighbors exist and are in the Up state + r3 = tgen.gears["r3"] + r3.vtysh_cmd( + """ + configure + router isis 1 + no redistribute ipv4 connected level-1 + no redistribute ipv4 connected level-2 + no redistribute ipv6 connected level-1 + no redistribute ipv6 connected level-2 + interface r3-eth1 + no isis circuit-type + isis network point-to-point + end + """ + ) + r5 = tgen.gears["r5"] + r5.vtysh_cmd( + """ + configure + router isis 1 + no redistribute ipv4 connected level-1 + no redistribute ipv6 connected level-1 + no redistribute ipv4 table 20 level-1 + interface r5-eth0 + no isis circuit-type + isis network point-to-point + end + """ + ) + result = _check_isis_neighbor_json("r3", "r5", True, "Up") + assert result is True, result + result = _check_isis_neighbor_json("r5", "r3", True, "Up") + assert result is True, result + + # Remove the configuration that affects the switch of IS-IS type. + # Configure the IS-IS type of r3 to transition from level-1-2 to level-2-only, + # while maintaining the IS-IS type of r5 as level-1. + # In this scenario, + # the expectation is that some neighbors do not exist or are in the Initializing state + r3.vtysh_cmd( + """ + configure + router isis 1 + is-type level-2-only + end + """ + ) + result = _check_isis_neighbor_json("r3", "r5", False, "Initializing") + assert result is True, result + result = _check_isis_neighbor_json("r5", "r3", False, "Initializing") + assert result is True, result + + # Restore to initial configuration + logger.info("Checking 'restore to initial configuration'") + r3.vtysh_cmd( + """ + configure + interface r3-eth1 + isis circuit-type level-1 + no isis network point-to-point + router isis 1 + no is-type + redistribute ipv4 connected level-1 + redistribute ipv4 connected level-2 + redistribute ipv6 connected level-1 + redistribute ipv6 connected level-2 + end + """ + ) + r5.vtysh_cmd( + """ + configure + interface r5-eth0 + isis circuit-type level-1 + no isis network point-to-point + router isis 1 + redistribute ipv4 connected level-1 + redistribute ipv6 connected level-1 + redistribute ipv4 table 20 level-1 + end + """ + ) + result = _check_isis_neighbor_json("r3", "r5", True, "Up") + assert result is True, result + result = _check_isis_neighbor_json("r5", "r3", True, "Up") + assert result is True, result + + def test_isis_database_json(): "Check json struct in show isis database json" @@ -623,6 +725,65 @@ def test_isis_hello_padding_during_adjacency_formation(): assert result is True, result +def _check_isis_neighbor_json( + self, neighbor, neighbor_expected, neighbor_state_expected +): + tgen = get_topogen() + router = tgen.gears[self] + logger.info( + f"check_isis_neighbor_json {router} {neighbor} {neighbor_expected} {neighbor_state_expected}" + ) + + result = _check_isis_neighbor_exist(self, neighbor) + if result == True: + return _check_isis_neighbor_state(self, neighbor, neighbor_state_expected) + elif neighbor_expected == True: + return "{} with expected neighbor {} got none ".format(router.name, neighbor) + else: + return True + + +@retry(retry_timeout=60) +def _check_isis_neighbor_exist(self, neighbor): + tgen = get_topogen() + router = tgen.gears[self] + logger.info(f"check_isis_neighbor_exist {router} {neighbor}") + neighbor_json = router.vtysh_cmd("show isis neighbor json", isjson=True) + + circuits = neighbor_json.get("areas", [])[0].get("circuits", []) + for circuit in circuits: + if "adj" in circuit and circuit["adj"] == neighbor: + return True + + return "The neighbor {} of router {} has not been learned yet ".format( + neighbor, router.name + ) + + +@retry(retry_timeout=5) +def _check_isis_neighbor_state(self, neighbor, neighbor_state_expected): + tgen = get_topogen() + router = tgen.gears[self] + logger.info( + f"check_isis_neighbor_state {router} {neighbor} {neighbor_state_expected}" + ) + neighbor_json = router.vtysh_cmd( + "show isis neighbor {} json".format(neighbor), isjson=True + ) + + circuits = neighbor_json.get("areas", [])[0].get("circuits", []) + for circuit in circuits: + interface = circuit.get("interface", {}) + if "state" in interface: + neighbor_state = interface["state"] + if neighbor_state == neighbor_state_expected: + return True + + return "{} peer with expected neighbor_state {} got {} ".format( + router.name, neighbor_state_expected, neighbor_state + ) + + @retry(retry_timeout=10) def check_last_iih_packet_for_padding(router, expect_padding): logfilename = "{}/{}".format(router.gearlogdir, "isisd.log")