Running on Ubuntu 22.04 ros2 humble

[leoguen]

Hi,

here is my experience to get the driver running on Ubuntu 22.04 and the Blueye X3 summarised by my AI and I. Thanks for this repo!

✅ Final Summary: Fixing Sonar-3D-15 ROS Driver on Ubuntu 22.04 + ROS 2 Humble

System Setup

OS: Ubuntu 22.04
ROS 2: Humble Hawksbill
Sonar: Waterlinked Sonar 3D-15

Network:
Sonar IP: 192.168.194.96
Host PC Ethernet IP: 192.168.1.90 & Netmask: 255.255.0.0

Interface: enp0s31f6

Problems Observed

• The ROS node blocked on:
  data, addr = self.sock.recvfrom(self.BUFFER_SIZE)

• tcpdump -i any showed no packets, and
  tcpdump -i enp0s31f6 host 224.0.0.96 and port 4747 neither

• The socket joined multicast with INADDR_ANY, which didn’t bind to the correct NIC.

• By default, the NIC was not accepting multicast packets.

---

Fixes Applied

1. Enable multicast on the NIC ("enp0s31f6" is mine, you can find yours with ifconfig)
   sudo ip link set enp0s31f6 multicast on
   After that tcpdump -i enp0s31f6 host 224.0.0.96 and port 4747 should show packages coming in

2. Join multicast on the correct IP (host IP, not INADDR_ANY)
   Replaced:
   mreq = struct.pack('4sL', group, socket.INADDR_ANY)
   self.sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)

   with:
   group = socket.inet_aton(self.MULTICAST_GROUP)
   local_ip = socket.inet_aton("192.168.1.90") # host PC IP
   mreq = struct.pack('4s4s', group, local_ip)
   self.sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
   self.get_logger().info("Joined multicast 224.0.0.96 on enp0s31f6 (192.168.1.90)")

3. Prevent blocking on empty reads
   self.sock.setblocking(False)
   try:
   data, addr = self.sock.recvfrom(self.BUFFER_SIZE)
   except BlockingIOError:
   return

---

Verification

• tcpdump -i enp0s31f6 host 224.0.0.96 and port 4747 shows steady UDP packets.
• ROS topics /sonar_point_cloud and /sonar_range_image now receive data.

---

Results

• Node now correctly receives multicast packets.
• recvfrom() no longer blocks.
• Sonar data is visible on ROS 2 topics and can be displayed in RViz once the Fixed Frame is set appropriately (so