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#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 <ctype.h>
#include "websocksy.h"
#include "builtins.h"
#include "network.h"
#include "websocket.h"
/* TODO
* - TLS
* - config parsing
* - backend config
* - framing config / per peer?
* - per-connection framing state
* - framing function discovery / registry
*/
/* Main loop condition, to be set from signal handler */
static volatile sig_atomic_t shutdown_requested = 0;
/* Core client registry */
static size_t socks = 0;
static websocket* sock = NULL;
/* Lowercase input string in-place */
char* xstr_lower(char* in){
size_t n;
for(n = 0; n < strlen(in); n++){
in[n] = tolower(in[n]);
}
return in;
}
/* Daemon configuration */
static struct {
char* host;
char* port;
ws_backend backend;
} config = {
.host = "::",
.port = "8001",
/* Assign the built-in defaultpeer backend by default */
.backend.init = backend_defaultpeer_init,
.backend.config = backend_defaultpeer_configure,
.backend.query = backend_defaultpeer_query,
.backend.cleanup = backend_defaultpeer_cleanup
};
/* Push a new client to the registry */
int client_register(websocket* ws){
size_t n = 0;
//try to find a slot to occupy
for(n = 0; n < socks; n++){
if(sock[n].ws_fd == -1){
break;
}
}
//none found, need to extend
if(n == socks){
sock = realloc(sock, (socks + 1) * sizeof(websocket));
if(!sock){
close(ws->ws_fd);
fprintf(stderr, "Failed to allocate memory\n");
return 1;
}
socks++;
}
sock[n] = *ws;
return 0;
}
void client_cleanup(){
size_t n;
for(n = 0; n < socks; n++){
ws_close(sock + n, ws_close_shutdown, "Shutting down");
}
free(sock);
sock = NULL;
socks = 0;
}
/* Establish peer connection for negotiated websocket */
int client_connect(websocket* ws){
int rv = 1;
ws->peer = config.backend.query(ws->request_path, ws->protocols, ws->protocol, ws->headers, ws->header, ws);
if(!ws->peer.host || !ws->peer.port){
//no peer provided
return 1;
}
//assign default framing function if none provided
if(!ws->peer.framing){
ws->peer.framing = framing_auto;
}
//TODO connection establishment should be async in the future
switch(ws->peer.transport){
case peer_tcp_client:
ws->peer_fd = network_socket(ws->peer.host, ws->peer.port, SOCK_STREAM, 0);
break;
case peer_udp_client:
ws->peer_fd = network_socket(ws->peer.host, ws->peer.port, SOCK_DGRAM, 0);
break;
case peer_tcp_server:
//TODO implement tcp server mode
fprintf(stderr, "TCP Server mode not yet implemented\n");
rv = 1;
break;
case peer_udp_server:
ws->peer_fd = network_socket(ws->peer.host, ws->peer.port, SOCK_DGRAM, 1);
break;
case peer_fifo_tx:
case peer_fifo_rx:
case peer_unix:
default:
//TODO implement other peer modes
fprintf(stderr, "Peer connection mode not yet implemented\n");
rv = 1;
break;
}
rv = (ws->peer_fd == -1) ? 1 : 0;
return rv;
}
/*
* Signal handler, attached to SIGINT
*/
static void signal_handler(int signum){
shutdown_requested = 1;
}
/*
* Usage info
*/
static int usage(char* fn){
fprintf(stderr, "\nwebsocksy v%s - Proxy between websockets and 'real' sockets\n", WEBSOCKSY_VERSION);
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;
}
static int ws_peer_data(websocket* ws){
ssize_t bytes_read, bytes_left = sizeof(ws->peer_buffer) - ws->peer_buffer_offset;
int64_t bytes_framed;
//default to a binary frame
ws_operation opcode = ws_frame_binary;
bytes_read = recv(ws->peer_fd, ws->peer_buffer + ws->peer_buffer_offset, bytes_left - 1, 0);
if(bytes_read < 0){
fprintf(stderr, "Failed to receive from peer: %s\n", strerror(errno));
ws_close(ws, ws_close_unexpected, "Peer connection failed");
return 0;
}
else if(bytes_read == 0){
//peer closed connection
ws_close(ws, ws_close_normal, "Peer closed connection");
return 0;
}
ws->peer_buffer[ws->peer_buffer_offset + bytes_read] = 0;
do{
//call the framing function
bytes_framed = ws->peer.framing(ws->peer_buffer, ws->peer_buffer_offset + bytes_read, bytes_read, &opcode, &(ws->peer_framing_data), ws->peer.framing_config);
if(bytes_framed > 0){
if(bytes_framed > ws->peer_buffer_offset + bytes_read){
ws_close(ws, ws_close_unexpected, "Internal error");
fprintf(stderr, "Overrun by framing function, have %lu + %lu bytes, framed %lu\n", ws->peer_buffer_offset, bytes_read, bytes_framed);
return 0;
}
//send the indicated n bytes to the websocket peer
if(ws_send_frame(ws, opcode, ws->peer_buffer, bytes_framed)){
return 1;
}
//copy back
memmove(ws->peer_buffer, ws->peer_buffer + bytes_framed, (ws->peer_buffer_offset + bytes_read) - bytes_framed);
//this should not actually happen, but it might with some weird framing functions/protocols
if(bytes_framed < ws->peer_buffer_offset){
ws->peer_buffer_offset -= bytes_framed;
}
else{
bytes_framed -= ws->peer_buffer_offset;
bytes_read -= bytes_framed;
ws->peer_buffer_offset = 0;
}
}
else if(bytes_framed < 0){
//TODO handle framing errors
}
}
while(bytes_framed && (ws->peer_buffer_offset + bytes_read) > 0);
ws->peer_buffer_offset += bytes_read;
return 0;
}
int main(int argc, char** argv){
fd_set read_fds;
size_t n;
int listen_fd = -1, status, max_fd;
//parse command line arguments
if(args_parse(argc - 1, argv + 1)){
exit(usage(argv[0]));
}
//initialize the selected peer discovery backend
if(config.backend.init() != WEBSOCKSY_API_VERSION){
fprintf(stderr, "The selected backend was built for another API version than the core\n");
exit(EXIT_FAILURE);
}
//open listening socket
listen_fd = network_socket(config.host, config.port, SOCK_STREAM, 1);
if(listen_fd < 0){
exit(usage(argv[0]));
}
//attach signal handler to catch Ctrl-C
signal(SIGINT, signal_handler);
//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].ws_fd >= 0){
FD_SET(sock[n].ws_fd, &read_fds);
if(max_fd < sock[n].ws_fd){
max_fd = sock[n].ws_fd;
}
if(sock[n].peer_fd >= 0){
FD_SET(sock[n].peer_fd, &read_fds);
if(max_fd < sock[n].peer_fd){
max_fd = sock[n].peer_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 or peer data ready
for(n = 0; n < socks; n++){
if(sock[n].ws_fd >= 0){
if(FD_ISSET(sock[n].ws_fd, &read_fds)){
if(ws_data(sock + n)){
break;
}
}
if(sock[n].peer_fd >= 0 && FD_ISSET(sock[n].peer_fd, &read_fds)){
if(ws_peer_data(sock + n)){
break;
}
}
}
}
}
}
//cleanup
if(config.backend.cleanup){
config.backend.cleanup();
}
client_cleanup();
close(listen_fd);
return 0;
}
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