Add --ip and --port flags for remote connections

[ballle98]

Feature Request

Add command-line flags to enable spdm-emu to connect to SPDM bridges on remote machines.

Problem

Currently spdm-emu hardcodes connections to localhost:2323, making it impossible to test SPDM bridges running on remote hosts or different machines.

Proposed Solution

Add two new flags:

• --ip <ip_address> - Specify remote bridge IP address
• --port <port_number> - Specify custom port number

Use Case

• port 2323 falls within the 2280-2379 Hyper-V/WSL2 reserves port range
• Development workflows where SPDM responder runs on separate hardware

Backward Compatibility

Maintain current defaults (localhost:2323) when flags are not provided.

[steven-bellock]

@ballle98 please squash the three commits into one.

@p-b-o it looks like this is implementing request 1 from #467.

[p-b-o]

@steven-bellock Indeed, that's great!
@ballle98 Would that be possible for you to add support for spdm_responder_emu also?
And spdm_emu/spdm_device_attester_sample/spdm_device_attester_sample.c while at it.

--- a/spdm_emu/spdm_responder_emu/spdm_responder_emu.c
+++ b/spdm_emu/spdm_responder_emu/spdm_responder_emu.c
@@ -276,11 +276,14 @@ int main(int argc, char *argv[])
     }

     if (m_use_transport_layer == SOCKET_TRANSPORT_TYPE_TCP) {
-        /* The IANA has assigned port number 4194 for SPDM */
-        result = platform_server_routine(TCP_SPDM_PLATFORM_PORT);
+        /* Use custom port if specified, otherwise default to 4194 for TCP */
+        uint16_t port = (m_custom_port != 0) ? m_custom_port : TCP_SPDM_PLATFORM_PORT;
+        result = platform_server_routine(port);
     }
     else {
-        result = platform_server_routine(DEFAULT_SPDM_PLATFORM_PORT);
+        /* Use custom port if specified, otherwise default to 2323 for other transports */
+        uint16_t port = (m_custom_port != 0) ? m_custom_port : DEFAULT_SPDM_PLATFORM_PORT;
+        result = platform_server_routine(port);
     }

With this, I've been able to change port and it's working as expected.
Thanks!