mirror of
https://github.com/kasmtech/KasmVNC.git
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377 lines
11 KiB
C
377 lines
11 KiB
C
/*
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* A WebSocket to TCP socket proxy with support for "wss://" encryption.
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* Copyright 2010 Joel Martin
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* Licensed under LGPL version 3 (see docs/LICENSE.LGPL-3)
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*
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* You can make a cert/key with openssl using:
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* openssl req -new -x509 -days 365 -nodes -out self.pem -keyout self.pem
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* as taken from http://docs.python.org/dev/library/ssl.html#certificates
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*/
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#include <stdio.h>
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#include <errno.h>
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#include <limits.h>
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#include <getopt.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <sys/un.h>
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#include <netinet/in.h>
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#include <netdb.h>
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#include <sys/select.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include "websocket.h"
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/*
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char USAGE[] = "Usage: [options] " \
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"[source_addr:]source_port target_addr:target_port\n\n" \
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" --verbose|-v verbose messages and per frame traffic\n" \
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" --daemon|-D become a daemon (background process)\n" \
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" --run-once handle a single WebSocket connection and exit\n" \
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" --cert CERT SSL certificate file\n" \
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" --key KEY SSL key file (if separate from cert)\n" \
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" --ssl-only disallow non-encrypted connections";
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*/
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extern int pipe_error;
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extern settings_t settings;
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static void do_proxy(ws_ctx_t *ws_ctx, int target) {
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fd_set rlist, wlist, elist;
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struct timeval tv;
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int maxfd, client = ws_ctx->sockfd;
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unsigned int opcode, left, ret;
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unsigned int tout_start, tout_end, cout_start, cout_end;
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unsigned int tin_start, tin_end;
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ssize_t len, bytes;
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tout_start = tout_end = cout_start = cout_end =
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tin_start = tin_end = 0;
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maxfd = client > target ? client+1 : target+1;
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while (1) {
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tv.tv_sec = 1;
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tv.tv_usec = 0;
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FD_ZERO(&rlist);
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FD_ZERO(&wlist);
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FD_ZERO(&elist);
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FD_SET(client, &elist);
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FD_SET(target, &elist);
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if (tout_end == tout_start) {
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// Nothing queued for target, so read from client
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FD_SET(client, &rlist);
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} else {
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// Data queued for target, so write to it
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FD_SET(target, &wlist);
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}
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if (cout_end == cout_start) {
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// Nothing queued for client, so read from target
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FD_SET(target, &rlist);
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} else {
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// Data queued for client, so write to it
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FD_SET(client, &wlist);
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}
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do {
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ret = select(maxfd, &rlist, &wlist, &elist, &tv);
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} while (ret == -1 && errno == EINTR);
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if (pipe_error) { break; }
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if (FD_ISSET(target, &elist)) {
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handler_emsg("target exception\n");
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break;
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}
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if (FD_ISSET(client, &elist)) {
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handler_emsg("client exception\n");
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break;
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}
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if (ret == -1) {
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handler_emsg("select(): %s\n", strerror(errno));
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break;
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} else if (ret == 0) {
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//handler_emsg("select timeout\n");
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continue;
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}
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if (FD_ISSET(target, &wlist)) {
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len = tout_end-tout_start;
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bytes = send(target, ws_ctx->tout_buf + tout_start, len, 0);
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if (pipe_error) { break; }
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if (bytes < 0) {
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handler_emsg("target connection error: %s\n",
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strerror(errno));
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break;
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}
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tout_start += bytes;
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if (tout_start >= tout_end) {
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tout_start = tout_end = 0;
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traffic(">");
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} else {
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traffic(">.");
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}
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}
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if (FD_ISSET(client, &wlist)) {
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len = cout_end-cout_start;
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bytes = ws_send(ws_ctx, ws_ctx->cout_buf + cout_start, len);
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if (pipe_error) { break; }
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if (len < 3) {
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handler_emsg("len: %d, bytes: %d: %d\n",
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(int) len, (int) bytes,
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(int) *(ws_ctx->cout_buf + cout_start));
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}
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cout_start += bytes;
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if (cout_start >= cout_end) {
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cout_start = cout_end = 0;
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traffic("<");
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} else {
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traffic("<.");
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}
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}
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if (FD_ISSET(target, &rlist)) {
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bytes = recv(target, ws_ctx->cin_buf, DBUFSIZE , 0);
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if (pipe_error) { break; }
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if (bytes <= 0) {
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handler_emsg("target closed connection\n");
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break;
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}
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cout_start = 0;
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if (ws_ctx->hybi) {
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cout_end = encode_hybi(ws_ctx->cin_buf, bytes,
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ws_ctx->cout_buf, BUFSIZE, ws_ctx->opcode);
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} else {
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cout_end = encode_hixie(ws_ctx->cin_buf, bytes,
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ws_ctx->cout_buf, BUFSIZE);
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}
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/*
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printf("encoded: ");
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for (i=0; i< cout_end; i++) {
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printf("%u,", (unsigned char) *(ws_ctx->cout_buf+i));
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}
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printf("\n");
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*/
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if (cout_end < 0) {
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handler_emsg("encoding error\n");
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break;
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}
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traffic("{");
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}
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if (FD_ISSET(client, &rlist)) {
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bytes = ws_recv(ws_ctx, ws_ctx->tin_buf + tin_end, BUFSIZE-1);
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if (pipe_error) { break; }
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if (bytes <= 0) {
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handler_emsg("client closed connection\n");
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break;
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}
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tin_end += bytes;
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/*
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printf("before decode: ");
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for (i=0; i< bytes; i++) {
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printf("%u,", (unsigned char) *(ws_ctx->tin_buf+i));
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}
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printf("\n");
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*/
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if (ws_ctx->hybi) {
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len = decode_hybi(ws_ctx->tin_buf + tin_start,
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tin_end-tin_start,
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ws_ctx->tout_buf, BUFSIZE-1,
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&opcode, &left);
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} else {
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len = decode_hixie(ws_ctx->tin_buf + tin_start,
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tin_end-tin_start,
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ws_ctx->tout_buf, BUFSIZE-1,
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&opcode, &left);
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}
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if (opcode == 8) {
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handler_msg("client sent orderly close frame\n");
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break;
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}
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/*
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printf("decoded: ");
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for (i=0; i< len; i++) {
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printf("%u,", (unsigned char) *(ws_ctx->tout_buf+i));
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}
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printf("\n");
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*/
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if (len < 0) {
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handler_emsg("decoding error\n");
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break;
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}
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if (left) {
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tin_start = tin_end - left;
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//printf("partial frame from client");
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} else {
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tin_start = 0;
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tin_end = 0;
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}
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traffic("}");
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tout_start = 0;
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tout_end = len;
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}
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}
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}
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void proxy_handler(ws_ctx_t *ws_ctx) {
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char sockname[32];
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sprintf(sockname, ".KasmVNCSock%u", getpid());
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struct sockaddr_un addr;
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addr.sun_family = AF_UNIX;
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strcpy(addr.sun_path, sockname);
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addr.sun_path[0] = '\0';
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struct timeval tv;
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gettimeofday(&tv, NULL);
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struct sockaddr_un myaddr;
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myaddr.sun_family = AF_UNIX;
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sprintf(myaddr.sun_path, ".%s@%s_%lu.%lu", ws_ctx->user, ws_ctx->ip,
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tv.tv_sec, tv.tv_usec);
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myaddr.sun_path[0] = '\0';
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int tsock = socket(AF_UNIX, SOCK_STREAM, 0);
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bind(tsock, (struct sockaddr *) &myaddr, sizeof(struct sockaddr_un));
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handler_msg("connecting to VNC target\n");
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if (connect(tsock, (struct sockaddr *) &addr,
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sizeof(sa_family_t) + strlen(sockname)) < 0) {
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handler_emsg("Could not connect to target: %s\n",
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strerror(errno));
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return;
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}
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do_proxy(ws_ctx, tsock);
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shutdown(tsock, SHUT_RDWR);
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close(tsock);
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}
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#if 0
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int main(int argc, char *argv[])
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{
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int fd, c, option_index = 0;
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static int ssl_only = 0, daemon = 0, run_once = 0, verbose = 0;
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char *found;
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static struct option long_options[] = {
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{"verbose", no_argument, &verbose, 'v'},
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{"ssl-only", no_argument, &ssl_only, 1 },
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{"daemon", no_argument, &daemon, 'D'},
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/* ---- */
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{"run-once", no_argument, 0, 'r'},
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{"cert", required_argument, 0, 'c'},
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{"key", required_argument, 0, 'k'},
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{0, 0, 0, 0}
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};
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settings.cert = realpath("self.pem", NULL);
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if (!settings.cert) {
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/* Make sure it's always set to something */
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settings.cert = "self.pem";
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}
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settings.key = "";
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while (1) {
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c = getopt_long (argc, argv, "vDrc:k:",
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long_options, &option_index);
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/* Detect the end */
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if (c == -1) { break; }
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switch (c) {
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case 0:
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break; // ignore
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case 1:
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break; // ignore
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case 'v':
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verbose = 1;
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break;
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case 'D':
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daemon = 1;
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break;
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case 'r':
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run_once = 1;
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break;
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case 'c':
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settings.cert = realpath(optarg, NULL);
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if (! settings.cert) {
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usage("No cert file at %s\n", optarg);
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}
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break;
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case 'k':
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settings.key = realpath(optarg, NULL);
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if (! settings.key) {
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usage("No key file at %s\n", optarg);
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}
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break;
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default:
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usage("");
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}
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}
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settings.verbose = verbose;
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settings.ssl_only = ssl_only;
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settings.daemon = daemon;
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settings.run_once = run_once;
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if ((argc-optind) != 2) {
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usage("Invalid number of arguments\n");
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}
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found = strstr(argv[optind], ":");
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if (found) {
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memcpy(settings.listen_host, argv[optind], found-argv[optind]);
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settings.listen_port = strtol(found+1, NULL, 10);
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} else {
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settings.listen_host[0] = '\0';
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settings.listen_port = strtol(argv[optind], NULL, 10);
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}
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optind++;
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if (settings.listen_port == 0) {
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usage("Could not parse listen_port\n");
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}
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found = strstr(argv[optind], ":");
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if (found) {
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memcpy(target_host, argv[optind], found-argv[optind]);
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target_port = strtol(found+1, NULL, 10);
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} else {
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usage("Target argument must be host:port\n");
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}
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if (target_port == 0) {
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usage("Could not parse target port\n");
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}
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if (ssl_only) {
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if (access(settings.cert, R_OK) != 0) {
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usage("SSL only and cert file '%s' not found\n", settings.cert);
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}
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} else if (access(settings.cert, R_OK) != 0) {
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fprintf(stderr, "Warning: '%s' not found\n", settings.cert);
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}
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//printf(" verbose: %d\n", settings.verbose);
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//printf(" ssl_only: %d\n", settings.ssl_only);
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//printf(" daemon: %d\n", settings.daemon);
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//printf(" run_once: %d\n", settings.run_once);
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//printf(" cert: %s\n", settings.cert);
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//printf(" key: %s\n", settings.key);
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settings.handler = proxy_handler;
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start_server();
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}
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#endif
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