support reading network config from kernel command line

This adds support for suppling network configuration on the
kernel command line in 2 ways:
 a.) kernel command line includes 'network-config=<base64>'
     value of that parameter is base64 encoded json (or yaml)
     it is taken as network config yaml.
     In order to save space on kernel command line, it can be
     base64 encoded gzipped json also.

 b.) ip= paired with files authored by klibc's ipconfig tool
     When network devices are brought up in the initramfs, klibc's
     ipconfig tool writes files are named /run/net-<DEVNAME>.conf.
     The best documentation available on that tool is
     /usr/share/doc/libklibc/README.ipconfig.gz.

Also changes util.get_cmdline() to return the command line of
pid 1 if it is in a container.  That is to make it consistent with
The systemd generator, and allow passing a command line to lxd,
as lxd does not mask /proc/cmdline.

1 files changed, 127 insertions, 0 deletions

diff --git a/tests/unittests/test_net.py b/tests/unittests/test_net.py
new file mode 100644
index 00000000..dfb31710
--- /dev/null
+++ b/tests/unittests/test_net.py
@@ -0,0 +1,127 @@
+from cloudinit import util
+from cloudinit import net
+from .helpers import TestCase
+
+import base64
+import copy
+import io
+import gzip
+import json
+import os
+
+DHCP_CONTENT_1 = """
+DEVICE='eth0'
+PROTO='dhcp'
+IPV4ADDR='192.168.122.89'
+IPV4BROADCAST='192.168.122.255'
+IPV4NETMASK='255.255.255.0'
+IPV4GATEWAY='192.168.122.1'
+IPV4DNS0='192.168.122.1'
+IPV4DNS1='0.0.0.0'
+HOSTNAME='foohost'
+DNSDOMAIN=''
+NISDOMAIN=''
+ROOTSERVER='192.168.122.1'
+ROOTPATH=''
+filename=''
+UPTIME='21'
+DHCPLEASETIME='3600'
+DOMAINSEARCH='foo.com'
+"""
+
+DHCP_EXPECTED_1 = {
+    'name': 'eth0',
+    'type': 'physical',
+    'subnets': [{'broadcast': '192.168.122.255',
+                 'gateway': '192.168.122.1',
+                 'dns_search': ['foo.com'],
+                 'type': 'dhcp',
+                 'netmask': '255.255.255.0',
+                 'dns_nameservers': ['192.168.122.1']}],
+}
+
+
+STATIC_CONTENT_1 = """
+DEVICE='eth1'
+PROTO='static'
+IPV4ADDR='10.0.0.2'
+IPV4BROADCAST='10.0.0.255'
+IPV4NETMASK='255.255.255.0'
+IPV4GATEWAY='10.0.0.1'
+IPV4DNS0='10.0.1.1'
+IPV4DNS1='0.0.0.0'
+HOSTNAME='foohost'
+UPTIME='21'
+DHCPLEASETIME='3600'
+DOMAINSEARCH='foo.com'
+"""
+
+STATIC_EXPECTED_1 = {
+    'name': 'eth1',
+    'type': 'physical',
+    'subnets': [{'broadcast': '10.0.0.255', 'gateway': '10.0.0.1',
+                 'dns_search': ['foo.com'], 'type': 'static',
+                 'netmask': '255.255.255.0',
+                 'dns_nameservers': ['10.0.1.1']}],
+}
+
+
+class TestNetConfigParsing(TestCase):
+    simple_cfg = {
+        'config': [{"type": "physical", "name": "eth0",
+                    "mac_address": "c0:d6:9f:2c:e8:80",
+                    "subnets": [{"type": "dhcp"}]}]}
+
+    def test_klibc_convert_dhcp(self):
+        found = net._klibc_to_config_entry(DHCP_CONTENT_1)
+        self.assertEqual(found, ('eth0', DHCP_EXPECTED_1))
+
+    def test_klibc_convert_static(self):
+        found = net._klibc_to_config_entry(STATIC_CONTENT_1)
+        self.assertEqual(found, ('eth1', STATIC_EXPECTED_1))
+
+    def test_config_from_klibc_net_cfg(self):
+        files = []
+        pairs = (('net-eth0.cfg', DHCP_CONTENT_1),
+                 ('net-eth1.cfg', STATIC_CONTENT_1))
+
+        macs = {'eth1': 'b8:ae:ed:75:ff:2b',
+                'eth0': 'b8:ae:ed:75:ff:2a'}
+
+        dhcp = copy.deepcopy(DHCP_EXPECTED_1)
+        dhcp['mac_address'] = macs['eth0']
+
+        static = copy.deepcopy(STATIC_EXPECTED_1)
+        static['mac_address'] = macs['eth1']
+
+        expected = {'version': 1, 'config': [dhcp, static]}
+        with util.tempdir() as tmpd:
+            for fname, content in pairs:
+                fp = os.path.join(tmpd, fname)
+                files.append(fp)
+                util.write_file(fp, content)
+
+            found = net.config_from_klibc_net_cfg(files=files, mac_addrs=macs)
+            self.assertEqual(found, expected)
+
+    def test_cmdline_with_b64(self):
+        data = base64.b64encode(json.dumps(self.simple_cfg).encode())
+        encoded_text = data.decode()
+        cmdline = 'ro network-config=' + encoded_text + ' root=foo'
+        found = net.read_kernel_cmdline_config(cmdline=cmdline)
+        self.assertEqual(found, self.simple_cfg)
+
+    def test_cmdline_with_b64_gz(self):
+        data = _gzip_data(json.dumps(self.simple_cfg).encode())
+        encoded_text = base64.b64encode(data).decode()
+        cmdline = 'ro network-config=' + encoded_text + ' root=foo'
+        found = net.read_kernel_cmdline_config(cmdline=cmdline)
+        self.assertEqual(found, self.simple_cfg)
+
+
+def _gzip_data(data):
+    with io.BytesIO() as iobuf:
+        gzfp = gzip.GzipFile(mode="wb", fileobj=iobuf)
+        gzfp.write(data)
+        gzfp.close()
+        return iobuf.getvalue()