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refactor(ec2): simplify convert_ec2_metadata_network_config
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Fixes: GH-4861

Co-authored-by: Chad Smith <chad.smith@canonical.com>
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@aciba90 @blackboxsw
aciba90 and blackboxsw committed Mar 19, 2024
1 parent a3aa44f commit 02515b8
Showing 1 changed file with 93 additions and 81 deletions.
174 changes: 93 additions & 81 deletions cloudinit/sources/DataSourceEc2.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@
from cloudinit import dmi, net, sources
from cloudinit import url_helper as uhelp
from cloudinit import util, warnings
from cloudinit.distros import Distro
from cloudinit.event import EventScope, EventType
from cloudinit.net import activators
from cloudinit.net.dhcp import NoDHCPLeaseError
Expand Down Expand Up @@ -947,6 +948,82 @@ def _get_key_as_int_or(dikt, key, alt_value):
}


def _configure_policy_routing(
dev_config: dict,
*,
nic_name: str,
nic_metadata: dict,
distro: Distro,
is_ipv4: bool,
table: int,
) -> None:
"""
Configure policy-based routing on secondary NICs / secondary IPs to
ensure outgoing packets are routed via the correct interface.
@param: dev_config: network cfg v2 to be updated inplace.
@param: nic_name: nic name. Only used if ipv4.
@param: nic_metadata: nic metadata from IMDS.
@param: distro: Instance of Distro. Only used if ipv4.
@param: is_ipv4: Boolean indicating if we are acting over ipv4 or not.
@param: table: Routing table id.
"""
if not dev_config.get("routes"):
dev_config["routes"] = []
if is_ipv4:
subnet_prefix_routes = nic_metadata["subnet-ipv4-cidr-block"]
ips = nic_metadata["local-ipv4s"]
try:
lease = distro.dhcp_client.dhcp_discovery(nic_name, distro=distro)
gateway = lease["routers"]
except NoDHCPLeaseError as e:
LOG.warning(
"Could not perform dhcp discovery on %s to find its "
"gateway. Not adding default route via the gateway. "
"Error: %s",
nic_name,
e,
)
else:
# Add default route via the NIC's gateway
dev_config["routes"].append(
{
"to": "0.0.0.0/0",
"via": gateway,
"table": table,
},
)
else:
subnet_prefix_routes = nic_metadata["subnet-ipv6-cidr-blocks"]
ips = nic_metadata["ipv6s"]

subnet_prefix_routes = (
[subnet_prefix_routes]
if isinstance(subnet_prefix_routes, str)
else subnet_prefix_routes
)
for prefix_route in subnet_prefix_routes:
dev_config["routes"].append(
{
"to": prefix_route,
"table": table,
},
)

if not dev_config.get("routing-policy"):
dev_config["routing-policy"] = []
# Packets coming from any IP associated with the current NIC
# will be routed using `table` routing table
ips = [ips] if isinstance(ips, str) else ips
for ip in ips:
dev_config["routing-policy"].append(
{
"from": ip,
"table": table,
},
)


def convert_ec2_metadata_network_config(
network_md,
distro,
Expand Down Expand Up @@ -1013,74 +1090,29 @@ def convert_ec2_metadata_network_config(
"match": {"macaddress": mac.lower()},
"set-name": nic_name,
}
# Configure policy-based routing on secondary NICs / secondary IPs to
# ensure outgoing packets are routed via the correct interface.
#
# This config only works on systems using Netplan because Networking
# config V2 does not support `routing-policy`, but this config is
# passed through on systems using Netplan.
# See: https://github.com/canonical/cloud-init/issues/4862
#
# If device-number is not present (AliYun or other ec2-like platforms),
# do not configure source-routing as we cannot determine which is the
# primary NIC.
table = 100 + nic_idx
if (
is_netplan
and nic_metadata.get("device-number")
and not is_primary_nic
):
dhcp_override["use-routes"] = True
table = 100 + nic_idx
if not dev_config.get("routes"):
dev_config["routes"] = []
try:
lease = distro.dhcp_client.dhcp_discovery(
nic_name, distro=distro
)
gateway = lease["routers"]
except NoDHCPLeaseError as e:
LOG.warning(
"Could not perform dhcp discovery on %s to find its "
"gateway. Not adding default route via the gateway. "
"Error: %s",
nic_name,
e,
)
else:
# Add default route via the NIC's gateway
dev_config["routes"].append(
{
"to": "0.0.0.0/0",
"via": gateway,
"table": table,
},
)
subnet_prefix_routes = nic_metadata["subnet-ipv4-cidr-block"]
subnet_prefix_routes = (
[subnet_prefix_routes]
if isinstance(subnet_prefix_routes, str)
else subnet_prefix_routes
_configure_policy_routing(
dev_config,
distro=distro,
nic_name=nic_name,
nic_metadata=nic_metadata,
is_ipv4=True,
table=table,
)
for prefix_route in subnet_prefix_routes:
dev_config["routes"].append(
{
"to": prefix_route,
"table": table,
},
)

if not dev_config.get("routing-policy"):
dev_config["routing-policy"] = []
# Packets coming from any IPv4 associated with the current NIC
# will be routed using `table` routing table
ipv4s = nic_metadata["local-ipv4s"]
ipv4s = [ipv4s] if isinstance(ipv4s, str) else ipv4s
for ipv4 in ipv4s:
dev_config["routing-policy"].append(
{
"from": ipv4,
"table": table,
},
)
if nic_metadata.get("ipv6s"): # Any IPv6 addresses configured
dev_config["dhcp6"] = True
dev_config["dhcp6-overrides"] = dhcp_override
Expand All @@ -1089,34 +1121,14 @@ def convert_ec2_metadata_network_config(
and nic_metadata.get("device-number")
and not is_primary_nic
):
table = 100 + nic_idx
if not dev_config.get("routes"):
dev_config["routes"] = []
subnet_prefix_routes = nic_metadata["subnet-ipv6-cidr-blocks"]
subnet_prefix_routes = (
[subnet_prefix_routes]
if isinstance(subnet_prefix_routes, str)
else subnet_prefix_routes
_configure_policy_routing(
dev_config,
distro=distro,
nic_name=nic_name,
nic_metadata=nic_metadata,
is_ipv4=False,
table=table,
)
for prefix_route in subnet_prefix_routes:
dev_config["routes"].append(
{
"to": prefix_route,
"table": table,
},
)

if not dev_config.get("routing-policy"):
dev_config["routing-policy"] = []
ipv6s = nic_metadata["ipv6s"]
ipv6s = [ipv6s] if isinstance(ipv6s, str) else ipv6s
for ipv6 in ipv6s:
dev_config["routing-policy"].append(
{
"from": ipv6,
"table": table,
},
)
dev_config["addresses"] = get_secondary_addresses(nic_metadata, mac)
if not dev_config["addresses"]:
dev_config.pop("addresses") # Since we found none configured
Expand Down

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