mdns.h File Reference

mDNS service discovery UI with terminal_screen rendering More...

Go to the source code of this file.

Data Structures
struct	ui_mdns_server_t
	Discovered server information from mDNS. More...
struct	ui_mdns_config_t
	Configuration for TUI discovery. More...

Macros
#define	TUI_MDNS_NAME_BUFFER_SIZE   256
#define	TUI_MDNS_SESSION_STRING_BUFFER_SIZE   256
#define	TUI_MDNS_ADDRESS_BUFFER_SIZE   256
#define	TUI_MDNS_IPV4_BUFFER_SIZE   16
#define	TUI_MDNS_IPV6_BUFFER_SIZE   46

Functions
void	ui_mdns_log_init (void)
	Discovered server information from mDNS.
void	ui_mdns_log_destroy (void)
	Destroy mDNS discovery log buffer.
void	ui_mdns_log_clear (void)
	Clear mDNS discovery log buffer.
void	ui_mdns_log_append (const char *message)
	Append message to mDNS discovery log buffer.
ui_mdns_server_t *	ui_mdns_query (const ui_mdns_config_t *config, int *out_count)
	Discover ascii-chat servers on the local network via mDNS.
void	ui_mdns_free_results (ui_mdns_server_t *servers)
	Free results from TUI discovery query.
int	ui_mdns_prompt_selection (const ui_mdns_server_t *servers, int count)
	Interactive server selection.
int	ui_mdns_select (const ui_mdns_server_t *servers, int count)
int	ui_mdns_select_until (const ui_mdns_server_t *servers, int count, uint64_t deadline)
int	ui_mdns_select_live (const ui_mdns_server_t *servers, int count, uint64_t deadline, ui_mdns_server_t *chosen)
const char *	ui_mdns_get_best_address (const ui_mdns_server_t *server)
	Get best address representation for a discovered server.

Detailed Description

mDNS service discovery UI with terminal_screen rendering

Implements interactive mDNS-based discovery of ascii-chat servers on the local network. Uses the shared terminal_screen infrastructure for consistent UI rendering with other modules.

Definition in file tui/mdns.h.

Macro Definition Documentation

TUI_MDNS_ADDRESS_BUFFER_SIZE

#define TUI_MDNS_ADDRESS_BUFFER_SIZE   256

Definition at line 14 of file tui/mdns.h.

TUI_MDNS_IPV4_BUFFER_SIZE

#define TUI_MDNS_IPV4_BUFFER_SIZE   16

Definition at line 15 of file tui/mdns.h.

TUI_MDNS_IPV6_BUFFER_SIZE

#define TUI_MDNS_IPV6_BUFFER_SIZE   46

Definition at line 16 of file tui/mdns.h.

TUI_MDNS_NAME_BUFFER_SIZE

#define TUI_MDNS_NAME_BUFFER_SIZE   256

Definition at line 12 of file tui/mdns.h.

TUI_MDNS_SESSION_STRING_BUFFER_SIZE

#define TUI_MDNS_SESSION_STRING_BUFFER_SIZE   256

Definition at line 13 of file tui/mdns.h.

Function Documentation

ui_mdns_free_results()

void ui_mdns_free_results

(

ui_mdns_server_t *

servers

)

Free results from TUI discovery query.

Releases memory allocated by ui_mdns_query().

Parameters

servers

Pointer to server array (safe to pass NULL)

Note

Safe to call multiple times or with NULL pointer

Free results from TUI discovery query.

Definition at line 100 of file tui/mdns.c.

                                                     {
  discovery_mdns_destroy(servers);
}

References discovery_mdns_destroy().

ui_mdns_get_best_address()

const char * ui_mdns_get_best_address

(

const ui_mdns_server_t *

server

)

Get best address representation for a discovered server.

Returns the most suitable address representation (IPv4 > IPv6 > hostname) for connecting to a discovered server.

Selection Priority:

1. IPv4 address (most universal)
2. IPv6 address
3. Advertised hostname (service labels are never connection destinations)

Parameters

server

Discovered server

Returns

Pointer to best address string (points to field in server struct)

Get best address representation for a discovered server.

Get best address for a server

Definition at line 439 of file tui/mdns.c.

                                                                     {
  if (!server) {
    return "";
  }
 
  // The service instance name is a display label, not a resolvable hostname.
  if (server->ipv4[0] != '\0') {
    return server->ipv4;
  }
  if (server->ipv6[0] != '\0') {
    return server->ipv6;
  }
 
  return server->address; // Fallback to address field
}

References ui_mdns_server_t::address, ui_mdns_server_t::ipv4, and ui_mdns_server_t::ipv6.

ui_mdns_log_append()

void ui_mdns_log_append

(

const char *

message

)

Append message to mDNS discovery log buffer.

Delegates to the logging system which automatically captures to session log buffer.

Parameters

message

Log message to append

Definition at line 68 of file tui/mdns.c.

                                             {
  if (message) {
    log_info("%s", message);
  }
}

References log_info.

ui_mdns_log_clear()

void ui_mdns_log_clear

(

void

)

Clear mDNS discovery log buffer.

Delegates to terminal_screen log clear. Useful when starting fresh mDNS discovery screen.

Definition at line 64 of file tui/mdns.c.

                             {
  terminal_screen_log_clear();
}

References terminal_screen_log_clear().

ui_mdns_log_destroy()

void ui_mdns_log_destroy

(

void

)

Destroy mDNS discovery log buffer.

Delegates to terminal_screen log cleanup.

Definition at line 59 of file tui/mdns.c.

                               {
  log_clear_session_log_buffer();
  terminal_screen_log_destroy();
}

References log_clear_session_log_buffer(), and terminal_screen_log_destroy().

ui_mdns_log_init()

void ui_mdns_log_init

(

void

)

Discovered server information from mDNS.

Configuration for TUI discovery

Initialize log buffer for mDNS discovery UI

Delegates to terminal_screen log initialization. Call once at startup before rendering mDNS discovery screen.

Definition at line 52 of file tui/mdns.c.

                            {
  session_log_buffer_t *buf = terminal_screen_log_init();
  if (buf) {
    log_set_session_log_buffer(buf);
  }
}

References log_set_session_log_buffer(), and terminal_screen_log_init().

ui_mdns_prompt_selection()

int ui_mdns_prompt_selection	(	const ui_mdns_server_t *	servers,
		int	count )

Interactive server selection.

Interactive controller picker; Enter selects the highlighted row, Esc/q cancels. Redirected input never chooses a server implicitly. Returns -1 when a terminal is unavailable.

Definition at line 107 of file tui/mdns.c.

                                                                         {
  if (terminal_can_prompt_user(!GET_OPTION(snapshot_mode)))
    return ui_mdns_select(servers, count);
  if (!servers || count <= 0) {
    return -1;
  }
 
  log_error("Cannot select a discovered server without an interactive terminal; specify a server address.");
  return -1;
}

References GET_OPTION, log_error, and ui_mdns_select().

ui_mdns_query()

ui_mdns_server_t * ui_mdns_query	(	const ui_mdns_config_t *	config,
		int *	out_count )

Discover ascii-chat servers on the local network via mDNS.

Performs an mDNS query for _ascii-chat._tcp services on the local network. Collects responses and returns discovered servers to the caller.

Behavior:

• Sends multicast mDNS query for _ascii-chat._tcp.local services
• Waits for responses for the specified timeout period
• Collects all discovered servers with their addresses and ports
• Returns array of discovered servers

Memory Management:

• Caller is responsible for freeing the returned array with ui_mdns_free_results()
• Returned servers are valid until ui_mdns_free_results() is called

Error Handling:

• Returns NULL and sets errno on initialization failure
• Partial results returned if mDNS init fails but discovery was attempted
• Network errors logged but don't prevent continuation

Threading:

• Blocking operation - waits for full timeout period
• Safe to call from main thread
• Does not spawn background threads

Parameters

config	Discovery configuration (NULL uses defaults)
out_count	Output parameter: number of discovered servers

Returns

Array of discovered servers, or NULL on error Must be freed with ui_mdns_free_results()

Note

Timeout includes network round-trip time, so 2000ms allows ~1.5s of actual waiting

Returns empty array (non-NULL with count=0) if no servers found, not NULL

Example:

ui_mdns_config_t config = {.timeout_ms = 2000, .max_servers = 20};
int count = 0;
ui_mdns_server_t *servers = ui_mdns_query(&config, &count);
 
if (servers && count > 0) {
    for (int i = 0; i < count; i++) {
        printf("%d: %s (%s:%d)\n", i+1, servers[i].name, servers[i].address, servers[i].port);
    }
    // User selects server...
    ui_mdns_free_results(servers);
}

Discover ascii-chat servers on the local network via mDNS.

TUI wrapper around core mDNS discovery

Calls discovery_mdns_query() from discovery.c with TUI-friendly configuration.

Definition at line 80 of file tui/mdns.c.

                                                                                {
  if (!out_count) {
    SET_ERRNO(ERROR_INVALID_PARAM, "out_count pointer is NULL");
    return NULL;
  }
 
  *out_count = 0;
 
  // Apply defaults if needed
  int timeout_ms = (config && config->timeout_ms > 0) ? config->timeout_ms : 2000;
  int max_servers = (config && config->max_servers > 0) ? config->max_servers : 20;
  bool quiet = (config && config->quiet);
 
  // Call the core mDNS discovery function from discovery.c
  return discovery_mdns_query(timeout_ms, max_servers, quiet, out_count);
}

References discovery_mdns_query(), ERROR_INVALID_PARAM, ui_mdns_config_t::max_servers, ui_mdns_config_t::quiet, SET_ERRNO, and ui_mdns_config_t::timeout_ms.

ui_mdns_select()

int ui_mdns_select	(	const ui_mdns_server_t *	servers,
		int	count )

Shared controller list: arrows/j/k move, Enter selects, digits choose by number, Esc/q cancels. Resizes retain the selection and scroll it into view. Returns -1 without waiting when no interactive terminal is available.

Definition at line 291 of file tui/mdns.c.

                                                               {
  if (!servers || count <= 0)
    return -1;
  return ui_mdns_select_until(servers, count, ui_input_deadline(30));
}

References ui_input_deadline(), and ui_mdns_select_until().

Referenced by ui_mdns_prompt_selection().

ui_mdns_select_live()

int ui_mdns_select_live	(	const ui_mdns_server_t *	servers,
		int	count,
		uint64_t	deadline,
		ui_mdns_server_t *	chosen )

Background LAN discovery while choosing; copies the selected endpoint into chosen. Returns 0 on selection, -1 on cancellation. Selection follows endpoint identity as the list changes; the worker is stopped and joined before returning.

Definition at line 419 of file tui/mdns.c.

                                                                                                                 {
  if (!chosen || count < 0 || count > MDNS_LIVE_CAPACITY || (count && !servers))
    return -1;
  mdns_refresh_t refresh = {0};
  refresh.count = count;
  if (count)
    memcpy(refresh.servers, servers, (size_t)count * sizeof(*servers));
  if (mutex_init(&refresh.mutex, "lan_results") != 0)
    return -1;
  int selected = select_mdns_until(servers, count, deadline, &refresh, chosen);
  mutex_destroy(&refresh.mutex);
  return selected < 0 ? -1 : 0;
}

References mdns_refresh_t::count, MDNS_LIVE_CAPACITY, mdns_refresh_t::mutex, and mdns_refresh_t::servers.

ui_mdns_select_until()

int ui_mdns_select_until	(	const ui_mdns_server_t *	servers,
		int	count,
		uint64_t	deadline )

Select with a caller-owned absolute monotonic deadline, retained across refreshes.

Definition at line 415 of file tui/mdns.c.

                                                                                        {
  return select_mdns_until(servers, count, deadline, NULL, NULL);
}

Referenced by ui_mdns_select().