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nhrpd: Add topotest for retrying resolution request

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Modified nhrp_topo topotest to test for newly added resolution
request retry feature. Changes to the topotest include adding a spoke to the
existing nhrp_topo topotest so that a topology with two spokes and hub
can be used to create shortcuts and test the sending/resending of
resolution requests and responses between spoke and hub. The resolution
request retry feature was tested by blocking incoming resolution requests on a
receiving nodes to stop the creation of a successful shortcut - which
then triggered the sending spoke to retry sending resolution requests

Signed-off-by: Joshua Muthii <jmuthii@labn.net>
This commit is contained in:
Joshua Muthii 2024-10-29 12:05:59 -04:00
parent 56495a88df
commit d599aa1da6
10 changed files with 334 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

14
tests/topotests/nhrp_topo/r1/nhrp_shortcut_present.json Normal file
View file

@ -0,0 +1,14 @@
{
"attr":{
"entriesCount":1
},
"table":[
{
"type":"dynamic",
"prefix":"192.168.4.0\/24",
"via":"10.255.255.4",
"identity":""
}
]
}

1
tests/topotests/nhrp_topo/r1/zebra.conf
View file

@ -10,3 +10,4 @@ exit
interface r1-eth1
ip address 192.168.1.1/24
!
ip route 0.0.0.0/0 10.255.255.2

13
tests/topotests/nhrp_topo/r2/nhrp4_cache.json
View file

@ -1,8 +1,19 @@
{
"attr":{
"entriesCount":2
"entriesCount":3
},
"table":[
{
"interface":"r2-gre0",
"type":"dynamic",
"protocol":"10.255.255.4",
"nbma":"10.1.1.4",
"claimed_nbma":"10.1.1.4",
"used":false,
"timeout":true,
"auth":false,
"identity":""
},
{
"interface":"r2-gre0",
"type":"local",

26
tests/topotests/nhrp_topo/r2/nhrp_route4.json
View file

@ -12,7 +12,31 @@
"installed":true,
"internalNextHopNum":1,
"internalNextHopActiveNum":1,
"nexthops":[
"nexthops": [
{
"fib":true,
"directlyConnected":true,
"interfaceName":"r2-gre0",
"active":true
}
]
}
],
"10.255.255.4\/32": [
{
"prefix":"10.255.255.4\/32",
"prefixLen":32,
"protocol":"nhrp",
"vrfId":0,
"vrfName":"default",
"selected":true,
"destSelected":true,
"distance":10,
"metric":0,
"installed":true,
"internalNextHopNum":1,
"internalNextHopActiveNum":1,
"nexthops": [
{
"fib":true,
"directlyConnected":true,

3
tests/topotests/nhrp_topo/r2/zebra.conf
View file

@ -1,3 +1,4 @@
ip forwarding
interface r2-eth0
ip address 10.2.1.2/24
!
@ -10,3 +11,5 @@ interface r2-gre0
interface r2-eth1
ip address 192.168.2.2/24
!
ip route 192.168.4.4/24 10.255.255.4
ip route 192.168.1.1/24 10.255.255.1

30
tests/topotests/nhrp_topo/r4/nhrp4_cache.json Normal file
View file

@ -0,0 +1,30 @@
{
"attr":{
"entriesCount":2
},
"table":[
{
"interface":"r4-gre0",
"type":"local",
"protocol":"10.255.255.4",
"nbma":"10.1.1.4",
"claimed_nbma":"10.1.1.4",
"used":false,
"timeout":false,
"auth":false,
"identity":"-"
},
{
"interface":"r4-gre0",
"type":"nhs",
"protocol":"10.255.255.2",
"nbma":"10.2.1.2",
"claimed_nbma":"10.2.1.2",
"used":false,
"timeout":true,
"auth":false,
"identity":""
}
]
}

26
tests/topotests/nhrp_topo/r4/nhrp_route4.json Normal file
View file

@ -0,0 +1,26 @@
{
"10.255.255.2\/32": [
{
"prefix": "10.255.255.2\/32",
"prefixLen": 32,
"protocol": "nhrp",
"vrfId": 0,
"vrfName": "default",
"selected": true,
"destSelected": true,
"distance": 10,
"metric": 0,
"installed": true,
"internalNextHopNum": 1,
"internalNextHopActiveNum": 1,
"nexthops": [
{
"fib": true,
"directlyConnected": true,
"interfaceName": "r4-gre0",
"active": true
}
]
}
]
}

11
tests/topotests/nhrp_topo/r4/nhrpd.conf Normal file
View file

@ -0,0 +1,11 @@
log stdout debugging
debug nhrp all
interface r4-gre0
ip nhrp authentication secret
ip nhrp holdtime 10
ip nhrp shortcut
ip nhrp network-id 42
ip nhrp nhs dynamic nbma 10.2.1.2
ip nhrp registration no-unique
tunnel source r4-eth0
exit

13
tests/topotests/nhrp_topo/r4/zebra.conf Normal file
View file

@ -0,0 +1,13 @@
interface r4-eth0
ip address 10.1.1.4/24
!
ip route 10.2.1.0/24 10.1.1.3
interface r4-gre0
ip address 10.255.255.4/32
no link-detect
ipv6 nd suppress-ra
exit
interface r4-eth1
ip address 192.168.4.4/24
!
ip route 0.0.0.0/0 10.255.255.2

210
tests/topotests/nhrp_topo/test_nhrp_topo.py
View file

@ -33,18 +33,52 @@ from lib.common_config import required_linux_kernel_version, retry
# Required to instantiate the topology builder class.
pytestmark = [pytest.mark.nhrpd]
TOPOLOGY = """
192.168.2.0/24
-----+-----
|
|
|
+----------+
| |
| R2 |
| NHS |
+----------+
| .2
|
|
|
GRE P2MP Between + 10.2.1.0/24
Between Spokes and Hub |
|
10.255.255.x/32 +----+-----+
| |
| R3 |
| |
+----+-----+
|.3
|
|
+----------+ | +---------+
| | | | | | |
| |R1 | | | R4 | |
192.168.1.0/24 +-------------|NHC +---------+----------| NHC | ------+ 192.168.4.0/24
| | |.1 .4| | |
| +----------+ 10.1.1.0/24 +---------+ |
"""
def build_topo(tgen):
"Build function"
# Create 3 routers.
for routern in range(1, 4):
# Create 4 routers.
for routern in range(1, 5):
tgen.add_router("r{}".format(routern))
switch = tgen.add_switch("s1")
switch.add_link(tgen.gears["r1"])
switch.add_link(tgen.gears["r3"])
switch.add_link(tgen.gears["r4"])
switch = tgen.add_switch("s2")
switch.add_link(tgen.gears["r2"])
switch.add_link(tgen.gears["r3"])
@ -53,6 +87,9 @@ def build_topo(tgen):
switch = tgen.add_switch("s4")
switch.add_link(tgen.gears["r1"])
switch = tgen.add_switch("s5")
switch.add_link(tgen.gears["r4"])
def _populate_iface():
tgen = get_topogen()
@ -62,6 +99,7 @@ def _populate_iface():
"echo 0 > /proc/sys/net/ipv4/ip_forward_use_pmtu",
"echo 1 > /proc/sys/net/ipv6/conf/{0}-eth0/disable_ipv6",
"echo 1 > /proc/sys/net/ipv6/conf/{0}-gre0/disable_ipv6",
"iptables -A FORWARD -i {0}-gre0 -o {0}-gre0 -m hashlimit --hashlimit-upto 4/minute --hashlimit-burst 1 --hashlimit-mode srcip,dstip --hashlimit-srcmask 24 --hashlimit-dstmask 24 --hashlimit-name loglimit-0 -j NFLOG --nflog-group 1 --nflog-range 128",
]
cmds_tot = [
@ -84,10 +122,27 @@ def _populate_iface():
output = tgen.net["r1"].cmd(input)
logger.info("output: " + output)
input = cmd.format("r4", "4")
logger.info("input: " + input)
output = tgen.net["r4"].cmd(input)
logger.info("output: " + output)
def _verify_iptables():
tgen = get_topogen()
# Verify iptables is installed
# This is needed for creating shortcuts
for rname in ("r1", "r4"):
rc, _, _ = tgen.net[rname].cmd_status("iptables --version")
if rc == 127:
return False
return True
def setup_module(mod):
"Sets up the pytest environment"
logger.info("NHRP Topology : \n {}".format(TOPOLOGY))
result = required_linux_kernel_version("5.0")
if result is not True:
pytest.skip("Kernel requirements are not met")
@ -103,7 +158,7 @@ def setup_module(mod):
TopoRouter.RD_ZEBRA,
os.path.join(CWD, "{}/zebra.conf".format(rname)),
)
if rname in ("r1", "r2"):
if rname in ("r1", "r2", "r4"):
router.load_config(
TopoRouter.RD_NHRP, os.path.join(CWD, "{}/nhrpd.conf".format(rname))
)
@ -226,10 +281,10 @@ def test_nhrp_connection():
# force session to reinitialize
def relink_session():
for r in ["r1", "r2"]:
for r in ["r1", "r2", "r4"]:
tgen.gears[r].vtysh_cmd("clear ip nhrp cache")
tgen.net[r].cmd("ip l del {}-gre0".format(r));
_populate_iface();
tgen.net[r].cmd("ip l del {}-gre0".format(r))
_populate_iface()
@retry(retry_timeout=40, initial_wait=5)
def verify_same_password():
@ -255,24 +310,29 @@ def test_nhrp_connection():
### Passwords are different
logger.info("Modify password and send ping again, should drop")
hubrouter.vtysh_cmd("""
hubrouter.vtysh_cmd(
"""
configure
interface r2-gre0
ip nhrp authentication secret12
""")
"""
)
relink_session()
verify_mismatched_password()
### Passwords are the same - again
logger.info("Recover password and verify conectivity is back")
hubrouter.vtysh_cmd("""
hubrouter.vtysh_cmd(
"""
configure
interface r2-gre0
ip nhrp authentication secret
""")
"""
)
relink_session()
verify_same_password()
def test_route_install():
"Test use of NHRP routes by other protocols (sharpd here)."
tgen = get_topogen()
@ -305,6 +365,134 @@ def test_route_install():
assert result is None, assertmsg
# Initial wait of 30 second because that is
# what the default purge time is for nhrp -
# here we are testing that all of the expected
# retries are sent and logged before a
# shortcut is purged
@retry(retry_timeout=10, initial_wait=30)
def check_retry_debug_info(pingspoke=None):
tgen = get_topogen()
r1 = tgen.gears["r1"]
if pingspoke == None:
pingspoke = r1
logger.info(f"Check retries are being sent from {pingspoke.name}")
output = pingspoke.cmd("grep -c 'Retrying Resolution Request' nhrpd.log")
# Making sure that we see all expected retries for a 30 second purge time
assertmsg = f"Did not see all expected retries on {pingspoke.name}"
assert output.strip() == "6", assertmsg
logger.info("Check retries are being sent OK")
# Helper function to ping between spokes and
# check for either complete or incomplete shortcut
# based on whichever one you are expecting -
# expect_succesful_shortcut inidcates whether
# you are expecting to find a complete shortcut
# (True) or incomplete shortcut (False) as a
# result of the ping
@retry(retry_timeout=10, initial_wait=10)
def create_shortcut(expect_successful_shortcut=True, pingspoke=None, peer_addr=None):
tgen = get_topogen()
r1 = tgen.gears["r1"]
if pingspoke == None:
pingspoke = r1
if peer_addr == None:
peer_addr = "192.168.4.4"
# Pinging the other spoke in an attempt to create specified type of shortcut
output = pingspoke.cmd(f"ping -c 10 -i .5 {peer_addr}")
print(output)
output = pingspoke.vtysh_cmd("show ip nhrp shortcut")
if expect_successful_shortcut:
logger.info(f"Check shortcut creation from {pingspoke.name} to {peer_addr}")
else:
logger.info(
f"Check incomplete shortcut creation from {pingspoke.name} to {peer_addr}"
)
output = pingspoke.vtysh_cmd("show ip nhrp shortcut")
print(output)
if expect_successful_shortcut:
json_file = "{}/{}/nhrp_shortcut_present.json".format(CWD, pingspoke.name)
expected = json.loads(open(json_file).read())
test_func = partial(
topotest.router_json_cmp, pingspoke, "show ip nhrp shortcut json", expected
)
_, result = topotest.run_and_expect(test_func, None, count=40, wait=0.5)
if result is not None:
assertmsg = (
"Shortcut is not being made between spoke {} and peer {}".format(
pingspoke.name, peer_addr
)
)
assert 0, assertmsg
else:
logger.info("Shortcut creation between spokes OK")
else:
# Currentlly, 'show ip nhrp shortcut json' does not show incomplete shortcuts
# so an explicit check for for the 'incompete' keyword needed here
if "incomplete" not in output:
assertmsg = (
"Incomplete shortcut between spoke {} and peer {} is not seen".format(
pingspoke.name, peer_addr
)
)
assert 0, assertmsg
else:
logger.info("Incomplete shortcut creation between spokes OK")
# This function tests the NHRP resolution request retries by dropping
# incoming packets (including the NHRP resolution request packets)
# from a receiving spoke in order to stop the NHRP resolution
# responses from ever being sent from that receiving spoke - and in turn
# resolution responses will not reach the sending spoke.
# This will trigger the NHRP resolution request retries which
# can be viewed through log messages.
def test_nhrp_retry_resolution():
""" "
Verify resolution requests are retried when resolution responses
are not received by a spoke
"""
tgen = get_topogen()
if tgen.routers_have_failure():
pytest.skip(tgen.errors)
# iptables used to create shortcuts
# and subsequent resolution request retries
if not _verify_iptables():
pytest.skip("iptables is not installed")
r1 = tgen.gears["r1"]
r4 = tgen.gears["r4"]
logger.info("Testing retrying resolution request functionality")
# Make sure that shortcut creation between spokes work
create_shortcut(expect_successful_shortcut=True)
# Clearing shortcut information for spokes
r1.vtysh_cmd("clear ip nhrp shortcut")
r4.vtysh_cmd("clear ip nhrp shortcut")
# Setting iptables rules to stop incoming packets on r4
# This should stop resolution requests from reaching
# the receiving router (r4) and hence stop the
# creation of a complete shortcut
r4.cmd("iptables -A INPUT -i r4-eth0 -j DROP")
# Make sure that nhrp debugging is enabled to read the retry logs
r1.vtysh_cmd(
"""
configure
debug nhrp all
"""
)
create_shortcut(expect_successful_shortcut=False)
# Look for retry logging output for resolution request retries
check_retry_debug_info()
# Undo iptables rule
r4.cmd("iptables -D INPUT -i r4-eth0 -j DROP")
def test_memory_leak():
"Run the memory leak test and report results."
tgen = get_topogen()