net: make new module from {forwarding,ssh,telnet}.py

net/forwarding.py

@@ -0,0 +1,51 @@
+import click
+import logging
+
+from exec.cmd import run_root_cmd
+from wrapper import check_programs_wrap
+
+from .ssh import run_ssh_command
+
+
+@click.command(name='forwarding')
+def cmd_forwarding():
+    """Enable network forwarding for a usb-attached device"""
+    check_programs_wrap(['syctl', 'iptables'])
+
+    logging.info("Enabling ipv4 forwarding with sysctl")
+    result = run_root_cmd([
+        'sysctl',
+        'net.ipv4.ip_forward=1',
+    ])
+    if result.returncode != 0:
+        click.Abort('Failed to enable ipv4 forward via sysctl')
+
+    logging.info("Enabling ipv4 forwarding with iptables")
+    result = run_root_cmd([
+        'iptables',
+        '-P',
+        'FORWARD',
+        'ACCEPT',
+    ])
+    if result.returncode != 0:
+        click.Abort('Failed set iptables rule')
+
+    logging.info("Enabling ipv4 NATting with iptables")
+    result = run_root_cmd([
+        'iptables',
+        '-A',
+        'POSTROUTING',
+        '-t',
+        'nat',
+        '-j',
+        'MASQUERADE',
+        '-s',
+        '172.16.42.0/24',
+    ])
+    if result.returncode != 0:
+        click.Abort('Failed set iptables rule')
+
+    logging.info("Setting default route on device via ssh")
+    result = run_ssh_command(cmd=['sudo -S route add default gw 172.16.42.2'], alloc_tty=True)
+    if result.returncode != 0:
+        click.Abort('Failed to add gateway over ssh')