docker-mac-routes-add.sh

#!/bin/bash

echoerr() { echo "ERROR: $@" 1>&2; }

# Check if the script is running on macOS
if [[ "$(uname)" != "Darwin" ]]; then
  echoerr "This script is intended to run on macOS only."
  exit 1
fi

echo "This tool supports Docker Desktop versions >= 4.26"

# Check if Docker Desktop is running
docker ps > /dev/null
if [ $? -ne 0 ]; then
  echoerr "Error with finding local Docker. Make sure Docker cli and Docker Desktop are installed."
  exit 1
fi


# Get IP of eth1 from BusyBox container with NET_ADMIN privileges
# Define the Docker command to get the IP address of eth1
DOCKER_COMMAND="ip addr show eth1 | grep 'inet ' | awk '{print \$2}' | cut -d/ -f1"

# Pull the BusyBox image if not already pulled
echo "Pulling BusyBox Docker image..."
docker pull busybox:latest

# Run the BusyBox container with network privileges (NET_ADMIN) and execute the command
echo "Running BusyBox container with network privileges (NET_ADMIN) to get IP address of eth1..."
IP_ADDRESS=$(docker run --rm --network host --cap-add NET_ADMIN busybox:latest sh -c "$DOCKER_COMMAND")

# Check if the IP address was successfully retrieved
if [ -n "$IP_ADDRESS" ]; then
  echo "IP address of eth1: $IP_ADDRESS"
else
  echoerr "Failed to retrieve IP address of eth1."
  echoerr "Make sure kernelForUDP is set, it is needed for this to work."
  echoerr "You can enable it manually from Docker Desktop GUI."
  echoerr "This is done from Settings(top right)->Resources->Network."
  echoerr "Enable 'Use kernel networking for UDP' in Docker Desktop."
  exit 1
fi

# List Docker networks with 'bridge' driver and display their subnets

echo "Listing Docker networks with 'bridge' driver and their subnets..."

# Get a list of all Docker networks with the 'bridge' driver
NETWORKS=$(docker network ls --filter driver=bridge --format "{{.ID}}")

# Iterate over each network and get its subnet
for NETWORK_ID in $NETWORKS; do
  # Inspect the network and extract the subnet information
  SUBNETS=$(docker network inspect --format '{{range .IPAM.Config}}{{.Subnet}}{{end}}' "$NETWORK_ID")

  # Get the network name for display purposes
  NETWORK_NAME=$(docker network inspect --format '{{.Name}}' "$NETWORK_ID")

  # Display the network name and its subnets
  if [ -n "$SUBNETS" ]; then
    echo "Network: $NETWORK_NAME (ID: $NETWORK_ID)"
    echo "  Subnet(s): $SUBNETS"

    # Check and Add/Remove Routes on macOS

    for SUBNET in $SUBNETS; do
      # Check if the route already exists
      echo "Checking for local routes already setup..."
      EXISTING_ROUTE=$(route -n get "$SUBNET" | grep destination: | grep -v default)

      if [ -n "$EXISTING_ROUTE" ]; then
        ROUTE_INFO=$(route -n get "$SUBNET")
        ROUTE_GATEWAY=$(echo "$ROUTE_INFO" | grep gateway: | awk '{print $2}')
        ROUTE_INTERFACE=$(echo "$ROUTE_INFO" | grep interface: | awk '{print $2}')
        echo "Route for subnet $SUBNET already exists:"
        echo "  subnet: $SUBNET gateway: $ROUTE_GATEWAY interface: $ROUTE_INTERFACE"
        # Check if the route to Docker VM already exists
        if [ "$ROUTE_GATEWAY" == "$IP_ADDRESS" ]; then
          echo "Skipping."
          continue
        fi

        # Ask to delete route to subnet before adding route to Docker VM
        read -p "Do you want to remove this existing route? (y/n): " CHOICE

        if [[ "$CHOICE" == "y" || "$CHOICE" == "Y" ]]; then
          # Remove the existing route
          echo "[NEED SUDO RIGHTS] Removing existing route for subnet $SUBNET..."
          sudo route -n delete -net $SUBNET
        else
          echo "Skipping route addition for subnet $SUBNET."
          continue
        fi
      fi

      # Add the new route for the subnet to the IP_ADDRESS
      echo "[NEED SUDO RIGHTS] Adding route to subnet $SUBNET via $IP_ADDRESS..."
      sudo route -n add -net $SUBNET $IP_ADDRESS
    done
  else
    echo "Network: $NETWORK_NAME (ID: $NETWORK_ID) has no defined subnets."
  fi
  echo "Done."
done