Basic connection handling

4 files changed, 307 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..0ac4e99
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+*.swp
+websocksy
diff --git a/makefile b/makefile
new file mode 100644
index 0000000..a7a0b45
--- /dev/null
+++ b/makefile
@@ -0,0 +1,8 @@
+CFLAGS=-g -Wall -Wpedantic
+
+all: websocksy
+
+websocksy: websocksy.c websocksy.h
+
+clean:
+	rm websocksy
diff --git a/websocksy.c b/websocksy.c
new file mode 100644
index 0000000..dba8124
--- /dev/null
+++ b/websocksy.c
@@ -0,0 +1,272 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "websocksy.h"
+
+/* TODO
+ * - TLS
+ * - config parsing
+ */
+
+static size_t socks = 0;
+static websocket* sock = NULL;
+
+static volatile sig_atomic_t shutdown_requested = 0;
+
+void signal_handler(int signum){
+	shutdown_requested = 1;
+}
+
+int usage(char* fn){
+	fprintf(stderr, "\nwebsocksy - Proxy between websockets and 'real' sockets\n");
+	fprintf(stderr, "Usage:\n");
+	fprintf(stderr, "\t%s [-p <port>] [-l <listen address>] [-b <targeting backend>]\n", fn);
+	return EXIT_FAILURE;
+}
+
+int args_parse(int argc, char** argv){
+	//TODO
+	return 0;
+}
+
+int network_socket(char* host, char* port, int socktype, int listener){
+	int fd = -1, status, yes = 1, flags;
+	struct addrinfo hints = {
+		.ai_family = AF_UNSPEC,
+		.ai_socktype = socktype,
+		.ai_flags = (listener ? AI_PASSIVE : 0)
+	};
+	struct addrinfo *info, *addr_it;
+
+	status = getaddrinfo(host, port, &hints, &info);
+	if(status){
+		fprintf(stderr, "Failed to parse address %s port %s: %s\n", host, port, gai_strerror(status));
+		return -1;
+	}
+
+	//traverse the result list
+	for(addr_it = info; addr_it; addr_it = addr_it->ai_next){
+		fd = socket(addr_it->ai_family, addr_it->ai_socktype, addr_it->ai_protocol);
+		if(fd < 0){
+			continue;
+		}
+
+		//set required socket options
+		yes = 1;
+		if(setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (void*)&yes, sizeof(yes)) < 0){
+			fprintf(stderr, "Failed to enable SO_REUSEADDR on socket: %s\n", strerror(errno));
+		}
+
+		yes = 0;
+		if(setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, (void*)&yes, sizeof(yes)) < 0){
+			fprintf(stderr, "Failed to unset IPV6_V6ONLY on socket: %s\n", strerror(errno));
+		}
+
+		//TODO loop, bcast for udp
+
+		if(listener){
+			status = bind(fd, addr_it->ai_addr, addr_it->ai_addrlen);
+			if(status < 0){
+				close(fd);
+				continue;
+			}
+		}
+		else{
+			status = connect(fd, addr_it->ai_addr, addr_it->ai_addrlen);
+			if(status < 0){
+				close(fd);
+				continue;
+			}
+		}
+
+		break;
+	}
+	freeaddrinfo(info);
+
+	if(!addr_it){
+		fprintf(stderr, "Failed to create socket for %s port %s\n", host, port);
+		return -1;
+	}
+
+	//set nonblocking
+	flags = fcntl(fd, F_GETFL, 0);
+	if(fcntl(fd, F_SETFL, flags | O_NONBLOCK) < 0){
+		fprintf(stderr, "Failed to set socket nonblocking: %s\n", strerror(errno));
+		close(fd);
+		return -1;
+	}
+
+	if(!listener){
+		return fd;
+	}
+
+	if(socktype == SOCK_STREAM){
+		status = listen(fd, SOMAXCONN);
+		if(status < 0){
+			fprintf(stderr, "Failed to listen on socket: %s\n", strerror(errno));
+			close(fd);
+			return -1;
+		}
+	}
+
+	return fd;
+}
+
+int ws_accept(int listen_fd){
+	size_t n = 0;
+	struct sockaddr_storage sa_storage;
+	socklen_t sa_length;
+
+	websocket ws = {
+		.fd = accept(listen_fd, (struct sockaddr*)&sa_storage, &sa_length)
+	};
+
+	//try to find a slot to occupy
+	for(n = 0; n < socks; n++){
+		if(sock[n].fd == -1){
+			break;
+		}
+	}
+
+	//none found, need to extend
+	if(n == socks){
+		sock = realloc(sock, (socks + 1) * sizeof(websocket));
+		if(!sock){
+			close(ws.fd);
+			fprintf(stderr, "Failed to allocate memory\n");
+			shutdown_requested = 1;
+			return 1;
+		}
+		socks++;
+	}
+
+	sock[n] = ws;
+
+	return 0;
+}
+
+int ws_data(websocket* ws){
+	//TODO
+	return -1;
+}
+
+int ws_peer_data(websocket* ws, size_t proto){
+	//TODO
+	return -1;
+}
+
+int ws_close(websocket* ws){
+	size_t p;
+
+	if(ws->fd >= 0){
+		close(ws->fd);
+		ws->fd = -1;
+	}
+
+	for(p = 0; p < ws->protocols; p++){
+		if(ws->protocol[p].fd >= 0){
+			close(ws->protocol[p].fd);
+			ws->protocol[p].fd = -1;
+			free(ws->protocol[p].name);
+		}
+	}
+
+	return 0;
+}
+
+int main(int argc, char** argv){
+	fd_set read_fds;
+	size_t n, p;
+	int listen_fd = -1, status, max_fd;
+
+	if(args_parse(argc - 1, argv + 1)){
+		exit(usage(argv[0]));
+	}
+
+	//open listening socket
+	listen_fd = network_socket(config.host, config.port, SOCK_STREAM, 1);
+	if(listen_fd < 0){
+		exit(usage(argv[0]));
+	}
+
+	//core loop
+	while(!shutdown_requested){
+		FD_ZERO(&read_fds);
+
+		FD_SET(listen_fd, &read_fds);
+		max_fd = listen_fd;
+
+		//push all fds to the select set
+		for(n = 0; n < socks; n++){
+			if(sock[n].fd >= 0){
+				FD_SET(sock[n].fd, &read_fds);
+				if(max_fd < sock[n].fd){
+					max_fd = sock[n].fd;
+				}
+
+				for(p = 0; p < sock[n].protocols; p++){
+					if(sock[n].protocol[p].fd >= 0){
+						FD_SET(sock[n].protocol[p].fd, &read_fds);
+						if(max_fd < sock[n].protocol[p].fd){
+							max_fd = sock[n].protocol[p].fd;
+						}
+					}
+				}
+			}
+		}
+
+		//block until something happens
+		status = select(max_fd + 1, &read_fds, NULL, NULL, NULL);
+		if(status < 0){
+			fprintf(stderr, "Failed to select: %s\n", strerror(errno));
+			break;
+		}
+		else if(status == 0){
+			//timeout in select - ignore for now
+		}
+		else{
+			//new websocket client
+			if(FD_ISSET(listen_fd, &read_fds)){
+				if(ws_accept(listen_fd)){
+					break;
+				}
+			}
+
+			//websocket & peer data
+			for(n = 0; n < socks; n++){
+				if(sock[n].fd >= 0){
+					if(FD_ISSET(sock[n].fd, &read_fds)){
+						if(ws_data(sock + n)){
+							break;
+						}
+					}
+
+					for(p = 0; p < sock[n].protocols; p++){
+						if(sock[n].protocol[p].fd >= 0 && FD_ISSET(sock[n].protocol[p].fd, &read_fds)){
+							if(ws_peer_data(sock + n, p)){
+								break;
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+
+	//cleanup
+	for(n = 0; n < socks; n++){
+		ws_close(sock + n);
+	}
+	free(sock);
+	socks = 0;
+	close(listen_fd);
+	return 0;
+}
diff --git a/websocksy.h b/websocksy.h
new file mode 100644
index 0000000..36a713d
--- /dev/null
+++ b/websocksy.h
@@ -0,0 +1,25 @@
+#include <stdint.h>
+#include <stdlib.h>
+
+struct {
+	char* host;
+	char* port;
+	struct {
+		char* name;
+	} backend;
+} config = {
+	.host = "::",
+	.port = "8001",
+	.backend.name = "internal"
+};
+
+typedef struct {
+	char* name;
+	int fd;
+} ws_proto;
+
+typedef struct /*_web_socket*/ {
+	int fd;
+	size_t protocols;
+	ws_proto* protocol;
+} websocket;