From 10701108fecb36f7be7eb7ef5f1e54e63da5fb4e Mon Sep 17 00:00:00 2001 From: Christian Breunig Date: Wed, 20 Dec 2023 22:25:47 +0100 Subject: vrf: T591: define sysctl setting for net.vrf.strict_mode Enable/Disable VRF strict mode, when net.vrf.strict_mode=0 (default) it is possible to associate multiple VRF devices to the same table. Conversely, when net.vrf.strict_mode=1 a table can be associated to a single VRF device. A VRF table can be used by the VyOS CLI only once (ensured by verify()), this simply adds an additional Kernel safety net, but a requirement for IPv6 segment routing headers. --- src/conf_mode/vrf.py | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'src/conf_mode') diff --git a/src/conf_mode/vrf.py b/src/conf_mode/vrf.py index 37625142c..9b1b6355f 100755 --- a/src/conf_mode/vrf.py +++ b/src/conf_mode/vrf.py @@ -214,6 +214,18 @@ def apply(vrf): # Delete the VRF Kernel interface call(f'ip link delete dev {tmp}') + # Enable/Disable VRF strict mode + # When net.vrf.strict_mode=0 (default) it is possible to associate multiple + # VRF devices to the same table. Conversely, when net.vrf.strict_mode=1 a + # table can be associated to a single VRF device. + # + # A VRF table can be used by the VyOS CLI only once (ensured by verify()), + # this simply adds an additional Kernel safety net + strict_mode = '0' + # Set to 1 if any VRF is defined + if 'name' in vrf: strict_mode = '1' + sysctl_write('net.vrf.strict_mode', strict_mode) + if 'name' in vrf: # Separate VRFs in conntrack table # check if table already exists -- cgit v1.2.3 From 774cc97eda61eb0b91df820797fb3c705d0073d5 Mon Sep 17 00:00:00 2001 From: Christian Breunig Date: Wed, 20 Dec 2023 22:38:52 +0100 Subject: srv6: T591: enable SR enabled packet processing on defined interfaces The Linux Kernel needs to be told if IPv6 SR enabled packets whether should be processed or not. This is done using /proc/sys/net/conf//seg6_* variables: seg6_enabled - BOOL Accept or drop SR-enabled IPv6 packets on this interface. Relevant packets are those with SRH present and DA = local. 0 - disabled (default) not 0 - enabled Or the VyOS CLI command: * set protocols segment-routing interface eth0 srv6 --- .../protocols-segment-routing.xml.in | 48 ++++++++++++++++ .../scripts/cli/test_protocols_segment_routing.py | 42 ++++++++++++++ src/conf_mode/protocols_segment_routing.py | 66 ++++++++++++++++++---- src/etc/sysctl.d/30-vyos-router.conf | 3 + 4 files changed, 148 insertions(+), 11 deletions(-) (limited to 'src/conf_mode') diff --git a/interface-definitions/protocols-segment-routing.xml.in b/interface-definitions/protocols-segment-routing.xml.in index d461e9c5d..4308f0c91 100644 --- a/interface-definitions/protocols-segment-routing.xml.in +++ b/interface-definitions/protocols-segment-routing.xml.in @@ -8,6 +8,54 @@ 900 + + + Interface specific Segment Routing options + + + + + txt + Interface name + + + #include + + + + + + Accept SR-enabled IPv6 packets on this interface + + + + + Define HMAC policy for ingress SR-enabled packets on this interface + + accept drop ignore + + + accept + Accept packets without HMAC, validate packets with HMAC + + + drop + Drop packets without HMAC, validate packets with HMAC + + + ignore + Ignore HMAC field. + + + (accept|drop|ignore) + + + accept + + + + + Segment-Routing SRv6 configuration diff --git a/smoketest/scripts/cli/test_protocols_segment_routing.py b/smoketest/scripts/cli/test_protocols_segment_routing.py index 81d42b925..403c05924 100755 --- a/smoketest/scripts/cli/test_protocols_segment_routing.py +++ b/smoketest/scripts/cli/test_protocols_segment_routing.py @@ -20,8 +20,10 @@ import unittest from base_vyostest_shim import VyOSUnitTestSHIM from vyos.configsession import ConfigSessionError +from vyos.ifconfig import Section from vyos.utils.process import cmd from vyos.utils.process import process_named_running +from vyos.utils.system import sysctl_read base_path = ['protocols', 'segment-routing'] PROCESS_NAME = 'zebra' @@ -45,6 +47,7 @@ class TestProtocolsSegmentRouting(VyOSUnitTestSHIM.TestCase): self.assertEqual(self.daemon_pid, process_named_running(PROCESS_NAME)) def test_srv6(self): + interfaces = Section.interfaces('ethernet', vlan=False) locators = { 'foo' : { 'prefix' : '2001:a::/64' }, 'foo' : { 'prefix' : '2001:b::/64', 'usid' : {} }, @@ -55,8 +58,18 @@ class TestProtocolsSegmentRouting(VyOSUnitTestSHIM.TestCase): if 'usid' in locator_config: self.cli_set(base_path + ['srv6', 'locator', locator, 'behavior-usid']) + # verify() - SRv6 should be enabled on at least one interface! + with self.assertRaises(ConfigSessionError): + self.cli_commit() + for interface in interfaces: + self.cli_set(base_path + ['interface', interface, 'srv6']) + self.cli_commit() + for interface in interfaces: + self.assertEqual(sysctl_read(f'net.ipv6.conf.{interface}.seg6_enabled'), '1') + self.assertEqual(sysctl_read(f'net.ipv6.conf.{interface}.seg6_require_hmac'), '0') # default + frrconfig = self.getFRRconfig(f'segment-routing', daemon='zebra') self.assertIn(f'segment-routing', frrconfig) self.assertIn(f' srv6', frrconfig) @@ -65,6 +78,35 @@ class TestProtocolsSegmentRouting(VyOSUnitTestSHIM.TestCase): self.assertIn(f' locator {locator}', frrconfig) self.assertIn(f' prefix {locator_config["prefix"]} block-len 40 node-len 24 func-bits 16', frrconfig) + def test_srv6_sysctl(self): + interfaces = Section.interfaces('ethernet', vlan=False) + + # HMAC accept + for interface in interfaces: + self.cli_set(base_path + ['interface', interface, 'srv6']) + self.cli_set(base_path + ['interface', interface, 'srv6', 'hmac', 'ignore']) + self.cli_commit() + + for interface in interfaces: + self.assertEqual(sysctl_read(f'net.ipv6.conf.{interface}.seg6_enabled'), '1') + self.assertEqual(sysctl_read(f'net.ipv6.conf.{interface}.seg6_require_hmac'), '-1') # ignore + + # HMAC drop + for interface in interfaces: + self.cli_set(base_path + ['interface', interface, 'srv6']) + self.cli_set(base_path + ['interface', interface, 'srv6', 'hmac', 'drop']) + self.cli_commit() + + for interface in interfaces: + self.assertEqual(sysctl_read(f'net.ipv6.conf.{interface}.seg6_enabled'), '1') + self.assertEqual(sysctl_read(f'net.ipv6.conf.{interface}.seg6_require_hmac'), '1') # drop + + # Disable SRv6 on first interface + first_if = interfaces[-1] + self.cli_delete(base_path + ['interface', first_if]) + self.cli_commit() + + self.assertEqual(sysctl_read(f'net.ipv6.conf.{first_if}.seg6_enabled'), '0') if __name__ == '__main__': unittest.main(verbosity=2) diff --git a/src/conf_mode/protocols_segment_routing.py b/src/conf_mode/protocols_segment_routing.py index eb1653212..d865c2ac0 100755 --- a/src/conf_mode/protocols_segment_routing.py +++ b/src/conf_mode/protocols_segment_routing.py @@ -19,7 +19,10 @@ import os from sys import exit from vyos.config import Config +from vyos.configdict import node_changed from vyos.template import render_to_string +from vyos.utils.dict import dict_search +from vyos.utils.system import sysctl_write from vyos import ConfigError from vyos import frr from vyos import airbag @@ -32,33 +35,74 @@ def get_config(config=None): conf = Config() base = ['protocols', 'segment-routing'] - sr = conf.get_config_dict(base, key_mangling=('-', '_'), get_first_key=True, no_tag_node_value_mangle=True) + sr = conf.get_config_dict(base, key_mangling=('-', '_'), + get_first_key=True, + no_tag_node_value_mangle=True, + with_recursive_defaults=True) - # We have gathered the dict representation of the CLI, but there are default - # options which we need to update into the dictionary retrived. - sr = conf.merge_defaults(sr, recursive=True) + # FRR has VRF support for different routing daemons. As interfaces belong + # to VRFs - or the global VRF, we need to check for changed interfaces so + # that they will be properly rendered for the FRR config. Also this eases + # removal of interfaces from the running configuration. + interfaces_removed = node_changed(conf, base + ['interface']) + if interfaces_removed: + sr['interface_removed'] = list(interfaces_removed) + import pprint + pprint.pprint(sr) return sr -def verify(static): +def verify(sr): + if 'srv6' in sr: + srv6_enable = False + if 'interface' in sr: + for interface, interface_config in sr['interface'].items(): + if 'srv6' in interface_config: + srv6_enable = True + break + if not srv6_enable: + raise ConfigError('SRv6 should be enabled on at least one interface!') return None -def generate(static): - if not static: +def generate(sr): + if not sr: return None - static['new_frr_config'] = render_to_string('frr/zebra.segment_routing.frr.j2', static) + sr['new_frr_config'] = render_to_string('frr/zebra.segment_routing.frr.j2', sr) return None -def apply(static): +def apply(sr): zebra_daemon = 'zebra' + if 'interface_removed' in sr: + for interface in sr['interface_removed']: + # Disable processing of IPv6-SR packets + sysctl_write(f'net.ipv6.conf.{interface}.seg6_enabled', '0') + + if 'interface' in sr: + for interface, interface_config in sr['interface'].items(): + # Accept or drop SR-enabled IPv6 packets on this interface + if 'srv6' in interface_config: + sysctl_write(f'net.ipv6.conf.{interface}.seg6_enabled', '1') + # Define HMAC policy for ingress SR-enabled packets on this interface + # It's a redundant check as HMAC has a default value - but better safe + # then sorry + tmp = dict_search('srv6.hmac', interface_config) + if tmp == 'accept': + sysctl_write(f'net.ipv6.conf.{interface}.seg6_require_hmac', '0') + elif tmp == 'drop': + sysctl_write(f'net.ipv6.conf.{interface}.seg6_require_hmac', '1') + elif tmp == 'ignore': + sysctl_write(f'net.ipv6.conf.{interface}.seg6_require_hmac', '-1') + else: + sysctl_write(f'net.ipv6.conf.{interface}.seg6_enabled', '0') + # Save original configuration prior to starting any commit actions frr_cfg = frr.FRRConfig() frr_cfg.load_configuration(zebra_daemon) frr_cfg.modify_section(r'^segment-routing') - if 'new_frr_config' in static: - frr_cfg.add_before(frr.default_add_before, static['new_frr_config']) + if 'new_frr_config' in sr: + frr_cfg.add_before(frr.default_add_before, sr['new_frr_config']) frr_cfg.commit_configuration(zebra_daemon) return None diff --git a/src/etc/sysctl.d/30-vyos-router.conf b/src/etc/sysctl.d/30-vyos-router.conf index 1c9b8999f..6291be5f0 100644 --- a/src/etc/sysctl.d/30-vyos-router.conf +++ b/src/etc/sysctl.d/30-vyos-router.conf @@ -105,3 +105,6 @@ net.core.rps_sock_flow_entries = 32768 net.core.default_qdisc=fq_codel net.ipv4.tcp_congestion_control=bbr +# Disable IPv6 Segment Routing packets by default +net.ipv6.conf.all.seg6_enabled = 0 +net.ipv6.conf.default.seg6_enabled = 0 -- cgit v1.2.3