Implement basic UDP broadcast/discovery

main.c

@@ -4,16 +4,20 @@
 
 #include "texture.h"
 #include "audio.h"
+#include "net.h"
 #include "log.h"
 
 #define SCREEN_WIDTH 640
 #define SCREEN_HEIGHT 480
 
+#define PORT 55555
+
 typedef enum {
 	SELECTING_DEVICE,
 	RECORDING,
 	RECORDED,
 	PLAYBACK,
+	SOCKET,
 } application_state;
 
 typedef struct {
@@ -45,7 +49,7 @@ int main(int argc, char* argv[])
 	char default_fmt[] = "Device selected: %i";
 
 	state state;
-	state.application_state = SELECTING_DEVICE;
+	state.application_state = SOCKET;
 	if (!audio_init(&state.audio)) return 1;
 	state.device_index = -1;
 	state.update_ui = 0;
@@ -203,6 +207,17 @@ int handle_input(SDL_Event* event, state* state)
 		}
 		break;
 
+	case SOCKET:
+		switch (keysym) {
+		case SDLK_1:
+			log_message(LOG_INFO, "Socket button 1 pressed");
+			net_broadcast();
+			break;
+		case SDLK_2:
+			log_message(LOG_INFO, "Socket button 2 pressed");
+			net_listen_clients();
+			break;
+		}
 	}
 	return 1;
 }
@@ -231,6 +246,8 @@ void handle_task(state* state)
 		}
 		break;
 
+	case SOCKET:
+		break;
 	}
 }
 
@@ -261,6 +278,8 @@ int init()
 		return 0;
 	}
 
+	net_init(PORT);
+
 	return 1;
 }
 
@@ -311,5 +330,8 @@ void application_state_to_string(application_state state, char* string)
 	case PLAYBACK:
 		sprintf(string, "Playing [ESC]: CANCEL");
 		break;
+	case SOCKET:
+		sprintf(string, "Socket");
+		break;
 	}
 }

net.c

@@ -0,0 +1,153 @@
+#include "net.h"
+#include "log.h"
+#include <stdio.h>
+
+typedef struct {
+	struct sockaddr_in addr;
+	int socket;
+	socklen_t addr_len;
+} net_info;
+
+static net_info broadcast_info;
+static net_info listen_info;
+static net_info peer_info;
+static int PORT;
+
+static int init = 0;
+
+int net_init(unsigned int port)
+{
+	PORT = port;
+	// broadcast socket init
+	broadcast_info.socket = socket(AF_INET, SOCK_DGRAM, 0);
+	if (broadcast_info.socket < 0) {
+		log_message(LOG_ERROR, "Error creating broadcast socket");
+		close(broadcast_info.socket);
+		return 0;
+	}
+
+	int broadcast_enable = 1;
+	if (setsockopt(broadcast_info.socket, SOL_SOCKET, SO_BROADCAST, &broadcast_enable, sizeof(broadcast_enable)) < 0) return 0;
+
+	memset(&broadcast_info.addr, 0, sizeof(broadcast_info.addr));
+	broadcast_info.addr.sin_family = AF_INET;
+	broadcast_info.addr.sin_addr.s_addr = inet_addr("255.255.255.255");
+	broadcast_info.addr.sin_port = htons(port);
+
+	broadcast_info.addr_len = sizeof(broadcast_info.addr);
+
+	// listen socket init
+	listen_info.socket = socket(AF_INET, SOCK_DGRAM, 0);
+	if (listen_info.socket < 0) {
+		log_message(LOG_ERROR, "Error creating listen socket", strerror(errno));
+		close(listen_info.socket);
+		return 0;
+	}
+
+	int reuse_enable = 1;
+	if (setsockopt(listen_info.socket, SOL_SOCKET, SO_REUSEADDR, &reuse_enable, sizeof(reuse_enable)) < 0) return 0;
+
+	memset(&listen_info.addr, 0, sizeof(listen_info.addr));
+	listen_info.addr.sin_family = AF_INET;
+	listen_info.addr.sin_addr.s_addr = INADDR_BROADCAST;
+	listen_info.addr.sin_port = htons(port);
+
+	listen_info.addr_len =sizeof(listen_info.addr);
+
+	struct timeval tv;
+	tv.tv_sec = 0;
+	tv.tv_usec = 100000;
+	setsockopt(listen_info.socket, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
+
+	if (bind(listen_info.socket, (const struct sockaddr*)&listen_info.addr, sizeof(listen_info.addr)) < 0) {
+		log_message(LOG_ERROR, "Socket bind failed: %s", strerror(errno));
+		close(listen_info.socket);
+		return 0;
+	}
+
+	peer_info.socket = -1;
+
+	init = 1;
+	return 1;
+}
+
+int net_broadcast()
+{
+	if (!init) return 0;;
+	const char* message = "broadcast message";
+	int retv = sendto(broadcast_info.socket, message,
+	                  strlen(message), 0,
+	                  (struct sockaddr*)&broadcast_info.addr,
+	                  broadcast_info.addr_len);
+	if (retv < 0) {
+		log_message(LOG_ERROR, "Failed to send broadcast message: %s", strerror(errno));
+		log_message(LOG_ERROR, "retv: %i", retv);
+		return 0;
+	}
+	log_message(LOG_INFO, "Broadcast message sent");
+	return 1;
+}
+
+int net_listen_clients()
+{
+	if (!init) return 0;
+
+	if (peer_info.socket >= 0) {
+		log_message(LOG_WARNING, "Peer socket already created");
+		log_message(LOG_INFO,
+		            "Peer socket address:\n%s:%d",
+		            inet_ntoa(peer_info.addr.sin_addr),
+		            ntohs(peer_info.addr.sin_port));
+		close(peer_info.socket);
+		peer_info.socket = -1;
+		//return 1;
+	}
+
+	peer_info.socket = socket(AF_INET, SOCK_DGRAM, 0);
+	if (peer_info.socket < 0) {
+		log_message(LOG_ERROR, "Error creating listen socket", strerror(errno));
+		close(peer_info.socket);
+		return 0;
+	}
+
+	char buffer[64];
+
+	memset(&peer_info.addr, 0, sizeof(peer_info.addr));
+	peer_info.addr.sin_family = AF_INET;
+	peer_info.addr.sin_addr.s_addr = INADDR_ANY;
+	peer_info.addr.sin_port = htons(PORT);
+
+	peer_info.addr_len = sizeof(peer_info.addr);
+
+	int retv = recvfrom(listen_info.socket, buffer, sizeof(buffer), 0,
+	                    (struct sockaddr*)&peer_info.addr,
+	                    &peer_info.addr_len);
+
+	if (retv < 0) {
+		log_message(LOG_ERROR, "Failed to receive broadcast message: %s", strerror(errno));
+		close(peer_info.socket);
+		peer_info.socket = -1;
+		return 0;
+	}
+
+	buffer[retv] = '\0';
+	log_message(LOG_INFO,
+	            "Broadcast message received from:\n%s:%d",
+	            inet_ntoa(peer_info.addr.sin_addr),
+	            ntohs(peer_info.addr.sin_port));
+	log_message(LOG_INFO, "%s", buffer);
+
+	return 1;
+}
+
+int net_send()
+{
+	if (!init) return 0;
+	return 1;
+}
+
+int net_receive()
+{
+	if (!init) return 0;
+	return 1;
+}

net.h

@@ -0,0 +1,16 @@
+#ifndef NET_H
+#define NET_H
+
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <ifaddrs.h>
+
+int net_init(unsigned int port);
+int net_broadcast();
+int net_listen_clients();
+int net_send();
+int net_receive();
+
+#endif