Manual Pages  — NETGDB

A netgdb session is started by using the netgdb -s server [-g gateway -c client -i iface ] command in ddb(4) to connect to a proxy server. When the connection is made, the proxy server logs a message that a netgdb client has connected. It subsequently establishes a TCP listening socket and logs a message specifying which port it is listening on. Then it waits for a GDB client to connect. The GDB command to connect is: target remote <proxyip:proxyport>

At this point, the server proxies traffic back and forth between netgdb and the ordinary GDB client, speaking the ordinary GDB remote protocol. The netgdb session is identical to any other kernel GDB sesssion from the perspective of the GDB debugger.

Unlike netdump(4), the initial HERALD port is 20025. Additionally, the proxy server sends responses to the source port of the client's initial HERALD, rather than a separate reserved port. netgdb message and acknowledgements are bidirectional. The sequence number and acknowledgement protocol is otherwise identical to the unidirectional version used by netdump; it just runs in both directions. Acknowledgements are sent to and from the same addresses and ports as regular messages.

The first version of the netgdb protocol uses the protocol number '0x2515f095' in the 32-bit aux2 parameter of the initial HERALD message.

The list of supported network drivers and protocol families is identical to that of netdump(4).