server.c File Reference

🌐 Client connection manager: TCP connection, reconnection with exponential backoff, and thread-safe transmission More...

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Macros
#define	DEBUG_NETWORK   1
#define	DEBUG_THREADS   1
#define	DEBUG_MEMORY   1
#define	MAX_RECONNECT_DELAY   (5 * 1000 * 1000)

Functions
int	server_connection_init ()
	Initialize the server connection management subsystem.
int	server_connection_establish (const char *address, int port, int reconnect_attempt, bool first_connection, bool has_ever_connected)
	Establish connection to ascii-chat server.
bool	server_connection_is_active ()
	Check if server connection is currently active.
socket_t	server_connection_get_socket ()
	Get current socket file descriptor.
acip_transport_t *	server_connection_get_transport (void)
	Get ACIP transport instance.
void	server_connection_set_transport (acip_transport_t *transport)
	Set ACIP transport instance from connection fallback.
uint32_t	server_connection_get_client_id ()
	Get client ID assigned by server.
const char *	server_connection_get_ip ()
	Get resolved server IP address.
void	server_connection_set_ip (const char *ip)
	Set the server IP address.
void	server_connection_close ()
	Close the server connection gracefully.
void	server_connection_shutdown ()
	Emergency connection shutdown for signal handlers.
void	server_connection_lost ()
	Signal that connection has been lost.
bool	server_connection_is_lost ()
	Check if connection loss has been detected.
void	server_connection_cleanup ()
	Cleanup connection management subsystem.
asciichat_error_t	threaded_send_packet (packet_type_t type, const void *data, size_t len)
	Thread-safe packet transmission.
int	threaded_send_audio_batch_packet (const float *samples, int num_samples, int batch_count)
	Thread-safe batched audio packet transmission.
asciichat_error_t	threaded_send_audio_opus (const uint8_t *opus_data, size_t opus_size, int sample_rate, int frame_duration)
	Thread-safe Opus audio frame transmission.
asciichat_error_t	threaded_send_audio_opus_batch (const uint8_t *opus_data, size_t opus_size, const uint16_t *frame_sizes, int frame_count)
	Thread-safe Opus audio batch packet transmission.
int	threaded_send_ping_packet (void)
	Thread-safe ping packet transmission.
int	threaded_send_pong_packet (void)
	Thread-safe pong packet transmission.
int	threaded_send_stream_start_packet (uint32_t stream_type)
	Thread-safe stream start packet transmission.
int	threaded_send_terminal_size_with_auto_detect (unsigned short width, unsigned short height)
	Thread-safe terminal size packet transmission with auto-detection.
int	threaded_send_client_join_packet (const char *display_name, uint32_t capabilities)
	Thread-safe client join packet transmission.

Variables
crypto_handshake_context_t	g_crypto_ctx = {0}
	Per-connection crypto handshake context.

Detailed Description

🌐 Client connection manager: TCP connection, reconnection with exponential backoff, and thread-safe transmission

The connection management follows a robust state machine:

1. Initialization: Socket creation and address resolution
2. Connection: TCP handshake with configurable timeout
3. Capability Exchange: Send terminal capabilities and client info
4. Active Monitoring: Health checks and keepalive management
5. Disconnection: Graceful or forced connection teardown
6. Reconnection: Exponential backoff retry logic

Thread Safety

All packet transmission functions use a global send mutex to prevent interleaved packets on the wire. The socket file descriptor is protected with atomic operations for thread-safe access across multiple threads.

Reconnection Strategy

Implements exponential backoff with jitter:

• Initial delay: 10ms
• Exponential growth: delay = 10ms + (200ms * attempt)
• Maximum delay: 5 seconds
• Jitter: Small random component to prevent thundering herd

Platform Compatibility

Uses platform abstraction layer for:

• Socket creation and management (Winsock vs BSD sockets)
• Network error handling and error string conversion
• Address resolution and connection timeout handling
• Socket options (keepalive, nodelay)

Integration Points

• main.c: Calls connection establishment and monitoring functions
• protocol.c: Uses thread-safe send functions for packet transmission
• keepalive.c: Monitors connection health and triggers reconnection
• capture.c: Sends media data through connection
• audio.c: Sends audio data through connection

Error Handling

Connection errors are classified into:

• Temporary: Network congestion, temporary DNS failures (retry)
• Permanent: Invalid address, authentication failure (report and exit)
• Timeout: Connection establishment timeout (retry with backoff)
• Loss: Existing connection broken (immediate reconnection attempt)

Author

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

Date

2025

Version

2.0

Definition in file src/client/server.c.

Macro Definition Documentation

DEBUG_MEMORY

#define DEBUG_MEMORY   1

Definition at line 96 of file src/client/server.c.

DEBUG_NETWORK

#define DEBUG_NETWORK   1

Definition at line 94 of file src/client/server.c.

DEBUG_THREADS

#define DEBUG_THREADS   1

Definition at line 95 of file src/client/server.c.

MAX_RECONNECT_DELAY

#define MAX_RECONNECT_DELAY   (5 * 1000 * 1000)

Maximum delay between reconnection attempts (microseconds)

Definition at line 215 of file src/client/server.c.