Acip_server

ACIP Packet Validation
asciichat_error_t	acip_server_validate_session_create (const acip_session_create_t *req)
	Validate ACIP session create request.
asciichat_error_t	acip_server_validate_session_join (const acip_session_join_t *req)
	Validate ACIP session join request.

ACIP Error Response Helpers
asciichat_error_t	acip_server_send_error (socket_t sockfd, acip_error_code_t error_code, const char *error_message)
	Send ACIP error response to client.

Detailed Description

Server-side ACIP (ASCII-Chat IP Protocol) utilities for:

• Packet validation and parsing
• Protocol compliance checking
• Error response generation
• Common server-side packet handling

ACIP Protocol Overview:

• Binary TCP protocol (not HTTP/JSON)
• Packet-based with CRC32 validation
• Ed25519 identity signatures
• Session management and WebRTC signaling

Primary Use Case: Library functions for building ACIP servers (like ACDS - ASCII-Chat Discovery Service). Provides reusable validation and packet handling logic that any ACIP server implementation can use.

Integration:

• Used by src/acds/ ACDS server implementation
• Can be used by custom ACIP server implementations
• Complements network/acip/client.h (client-side protocol)

Note

This module provides library-level utilities. The ACDS server application code is in src/acds/.

See also

network/acip/client.h for client-side ACIP library

network/acip/acds.h for ACDS message structures

network/acip/protocol.h for ACIP Packet Types types

Author

Zachary Fogg me@zf.nosp@m.o.gg

Date

January 2026

Version

1.0 (ACIP Protocol Refactoring)

Function Documentation

acip_server_send_error()

asciichat_error_t acip_server_send_error	(	socket_t	sockfd,
		acip_error_code_t	error_code,
		const char *	error_message
	)

#include <acds_server.h>

Send ACIP error response to client.

Parameters

sockfd	Client socket
error_code	ACIP error code
error_message	Human-readable error message (max 255 chars)

Returns

ASCIICHAT_OK on success, error code on failure

Sends PACKET_TYPE_ACIP_ERROR response to client with specified error code and message. Message will be truncated if longer than 255 characters.

Definition at line 77 of file acds_server.c.

                                                                                                                   {
  if (sockfd == INVALID_SOCKET_VALUE) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Invalid socket");
  }
 
  if (!error_message) {
    error_message = "Unknown error";
  }
 
  acip_error_t error_packet;
  memset(&error_packet, 0, sizeof(error_packet));
  error_packet.error_code = (uint8_t)error_code;
 
  // Safely copy error message (truncate if needed)
  size_t msg_len = strlen(error_message);
  if (msg_len >= sizeof(error_packet.error_message)) {
    msg_len = sizeof(error_packet.error_message) - 1;
  }
  memcpy(error_packet.error_message, error_message, msg_len);
  error_packet.error_message[msg_len] = '\0';
 
  // Send ACIP_ERROR packet
  int result = send_packet(sockfd, PACKET_TYPE_ACIP_ERROR, &error_packet, sizeof(error_packet));
  if (result < 0) {
    return SET_ERRNO(ERROR_NETWORK, "Failed to send ACIP error packet");
  }
 
  return ASCIICHAT_OK;
}

References acip_error_t, ASCIICHAT_OK, error_code, ERROR_INVALID_PARAM, ERROR_NETWORK, INVALID_SOCKET_VALUE, PACKET_TYPE_ACIP_ERROR, send_packet(), and SET_ERRNO.

acip_server_validate_session_create()

asciichat_error_t acip_server_validate_session_create

(

const acip_session_create_t *

req

)

#include <acds_server.h>

Validate ACIP session create request.

Parameters

req	Session create request packet

Returns

ASCIICHAT_OK if valid, error code if invalid

Validates that a SESSION_CREATE request has all required fields populated correctly (identity, signature, capabilities, etc.).

Definition at line 27 of file acds_server.c.

                                                                                        {
  if (!req) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Session create request is NULL");
  }
 
  // Validate capabilities (only bits 0-1 should be set)
  if (req->capabilities & ~0x03) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Invalid capabilities bits (only 0-1 allowed)");
  }
 
  // Validate max_participants (1-8)
  if (req->max_participants < 1 || req->max_participants > 8) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Invalid max_participants (must be 1-8)");
  }
 
  // Validate server address is not empty
  if (req->server_address[0] == '\0') {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Server address is empty");
  }
 
  // Validate server port is non-zero
  if (req->server_port == 0) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Server port is zero");
  }
 
  return ASCIICHAT_OK;
}

References ASCIICHAT_OK, ERROR_INVALID_PARAM, and SET_ERRNO.

acip_server_validate_session_join()

asciichat_error_t acip_server_validate_session_join

(

const acip_session_join_t *

req

)

#include <acds_server.h>

Validate ACIP session join request.

Parameters

req	Session join request packet

Returns

ASCIICHAT_OK if valid, error code if invalid

Validates that a SESSION_JOIN request has all required fields populated correctly (session string, identity, signature, etc.).

Definition at line 55 of file acds_server.c.

                                                                                    {
  if (!req) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Session join request is NULL");
  }
 
  // Validate session string length
  if (req->session_string_len == 0 || req->session_string_len > ACIP_MAX_SESSION_STRING_LEN) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Invalid session string length");
  }
 
  // Validate session string is not empty
  if (req->session_string[0] == '\0') {
    return SET_ERRNO(ERROR_INVALID_PARAM, "Session string is empty");
  }
 
  return ASCIICHAT_OK;
}

References ACIP_MAX_SESSION_STRING_LEN, ASCIICHAT_OK, ERROR_INVALID_PARAM, and SET_ERRNO.