Add support for DHCP server/relay

This patch introduces a new yang yang model for DHCP server and relay,
using dnsmasq to provide the functionality on a per-interface basis.

Available DHCP options will be queried by confd on startup and can
then be configured in a flexible manner.

The DHCP option 82 feature has been realized by patching dnsmasq
(see patches/dnsmasq/2.90/0000-relay-agent-info.patch).

Signed-off-by: Stefan Schlosser <sgs@grmmbl.org>

src/statd/python/cli_pretty/cli_pretty.py

@@ -57,6 +57,12 @@ class PadSoftware:
     state = 10
     version = 23
 
+class PadDhcpServer:
+    iface = 7
+    ip = 17
+    mac = 19
+    host = 21
+    exp = 7
 
 class PadUsbPort:
     title = 30
@@ -350,6 +356,34 @@ class STPPortID:
         )
         return f"{prio:1x}.{pid:03x}"
 
+class DhcpServer:
+    def __init__(self, data):
+        self.data = data
+        self.iface = get_json_data('', self.data, 'if-name')
+        self.leases = []
+        now = datetime.now(timezone.utc)
+        for lease in get_json_data([], self.data, 'server', 'lease', 'host'):
+            dt = datetime.strptime(lease["expires"], "%Y-%m-%dT%H:%M:%S%z")
+            exp =  (dt - now).total_seconds()
+            self.leases.append({
+               "ip": lease["ip-address"],
+               "mac": lease["hardware-address"],
+               "host": lease["hostname"],
+               "exp": int(exp)
+            })
+
+    def print(self):
+        for lease in self.leases:
+            ip = lease["ip"]
+            mac = lease["mac"]
+            exp = "%ds" % lease["exp"]
+            host = lease["host"][:20]
+            row = f"{self.iface:<{PadDhcpServer.iface}}"
+            row += f"{ip:<{PadDhcpServer.ip}}"
+            row += f"{mac:<{PadDhcpServer.mac}}"
+            row += f"{host:<{PadDhcpServer.host}}"
+            row += f"{exp:<{PadDhcpServer.exp}}"
+            print(row)
 
 class Iface:
     def __init__(self, data):
@@ -1038,6 +1072,23 @@ def show_ntp(json):
         row += f"{source['poll']:>{PadNtpSource.poll}}"
         print(row)
 
+def show_dhcp_server(json):
+    if not json.get("infix-dhcp-server:dhcp-server"):
+        print("DHCP server not enabled.")
+        return
+
+    hdr = (f"{'IFACE':<{PadDhcpServer.iface}}"
+           f"{'IP':<{PadDhcpServer.ip}}"
+           f"{'MAC':<{PadDhcpServer.mac}}"
+           f"{'HOSTNAME':<{PadDhcpServer.host}}"
+           f"{'EXPIRES':<{PadDhcpServer.exp}}")
+    print(Decore.invert(hdr))
+
+    servers = get_json_data({}, json, "infix-dhcp-server:dhcp-server", "server-if")
+    for s in servers:
+        server = DhcpServer(s)
+        server.print()
+
 def main():
     global UNIT_TEST
 
@@ -1074,6 +1125,8 @@ def main():
 
     parser_show_boot_order = subparsers.add_parser('show-boot-order', help='Show NTP sources')
 
+    parser_show_routing_table = subparsers.add_parser('show-dhcp-server', help='Show DHCP server')
+
     args = parser.parse_args()
     UNIT_TEST = args.test
 
@@ -1091,6 +1144,8 @@ def main():
         show_hardware(json_data)
     elif args.command == "show-ntp":
         show_ntp(json_data)
+    elif args.command == "show-dhcp-server":
+        show_dhcp_server(json_data)
     else:
         print(f"Error, unknown command '{args.command}'")
         sys.exit(1)