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#define _GNU_SOURCE
#include "logutils.h"
#include "netutils.h"
#include <uv.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#undef _GNU_SOURCE
#define IF_VERBOSE if (g_verbose)
#define DNS2TCP_VERSION "dns2tcp v1.0"
static bool g_verbose = false;
static uv_loop_t *g_evloop = NULL;
static uv_udp_t *g_udp_server = NULL;
static char g_listen_ipstr[IP6STRLEN] = {0};
static portno_t g_listen_portno = 0;
static skaddr6_t g_listen_skaddr = {0};
static char g_remote_ipstr[IP6STRLEN] = {0};
static portno_t g_remote_portno = 0;
static skaddr6_t g_remote_skaddr = {0};
static void udp_alloc_cb(uv_handle_t *udp_server, size_t sugsize, uv_buf_t *uvbuf);
static void udp_recv_cb(uv_udp_t *udp_server, ssize_t nread, const uv_buf_t *uvbuf, const skaddr_t *skaddr, unsigned flags);
static void tcp_connect_cb(uv_connect_t *connreq, int status);
static void tcp_write_cb(uv_write_t *writereq, int status);
static void tcp_alloc_cb(uv_handle_t *tcp_client, size_t sugsize, uv_buf_t *uvbuf);
static void tcp_read_cb(uv_stream_t *tcp_client, ssize_t nread, const uv_buf_t *uvbuf);
static void tcp_close_cb(uv_handle_t *tcp_client);
static void print_command_help(void) {
printf("usage: dns2tcp <-L LISTEN_ADDR> <-R REMOTE_ADDR> [-vVh]\n"
" -L <ip#port> udp listen address, it is required\n"
" -R <ip#port> tcp remote address, it is required\n"
" -v print verbose log, default: <disabled>\n"
" -V print version number of dns2tcp and exit\n"
" -h print help information of dns2tcp and exit\n"
"bug report: https://github.com/zfl9/dns2tcp. email: zfl9.com@gmail.com\n"
);
}
static void parse_address_opt(char *ip_port_str, bool is_listen_addr) {
const char *opt_name = is_listen_addr ? "listen" : "remote";
char *portstr = strchr(ip_port_str, '#');
if (!portstr) {
printf("[parse_address_opt] %s port is not specified\n", opt_name);
goto PRINT_HELP_AND_EXIT;
}
if (portstr == ip_port_str) {
printf("[parse_address_opt] %s addr is not specified\n", opt_name);
goto PRINT_HELP_AND_EXIT;
}
*portstr = 0; ++portstr;
if (strlen(portstr) + 1 > PORTSTRLEN) {
printf("[parse_address_opt] %s port is invalid: %s\n", opt_name, portstr);
goto PRINT_HELP_AND_EXIT;
}
portno_t portno = strtol(portstr, NULL, 10);
if (portno == 0) {
printf("[parse_address_opt] %s port is invalid: %s\n", opt_name, portstr);
goto PRINT_HELP_AND_EXIT;
}
char *ipstr = ip_port_str;
if (strlen(ipstr) + 1 > IP6STRLEN) {
printf("[parse_address_opt] %s addr is invalid: %s\n", opt_name, ipstr);
goto PRINT_HELP_AND_EXIT;
}
int ipfamily = get_ipstr_family(ipstr);
if (ipfamily == -1) {
printf("[parse_address_opt] %s addr is invalid: %s\n", opt_name, ipstr);
goto PRINT_HELP_AND_EXIT;
}
void *skaddr_ptr = is_listen_addr ? &g_listen_skaddr : &g_remote_skaddr;
if (ipfamily == AF_INET) {
build_ipv4_addr(skaddr_ptr, ipstr, portno);
} else {
build_ipv6_addr(skaddr_ptr, ipstr, portno);
}
if (is_listen_addr) {
strcpy(g_listen_ipstr, ipstr);
g_listen_portno = portno;
} else {
strcpy(g_remote_ipstr, ipstr);
g_remote_portno = portno;
}
return;
PRINT_HELP_AND_EXIT:
print_command_help();
exit(1);
}
static void parse_command_args(int argc, char *argv[]) {
char *opt_listen_addr = NULL;
char *opt_remote_addr = NULL;
opterr = 0;
int shortopt = -1;
const char *optstr = "L:R:vVh";
while ((shortopt = getopt(argc, argv, optstr)) != -1) {
switch (shortopt) {
case 'L':
opt_listen_addr = optarg;
break;
case 'R':
opt_remote_addr = optarg;
break;
case 'v':
g_verbose = true;
break;
case 'V':
printf(DNS2TCP_VERSION"\n");
exit(0);
case 'h':
print_command_help();
exit(0);
case '?':
if (!strchr(optstr, optopt)) {
printf("[parse_command_args] unknown option '-%c'\n", optopt);
} else {
printf("[parse_command_args] missing optval '-%c'\n", optopt);
}
goto PRINT_HELP_AND_EXIT;
}
}
if (!opt_listen_addr) {
printf("[parse_command_args] missing option: '-L'\n");
goto PRINT_HELP_AND_EXIT;
}
if (!opt_remote_addr) {
printf("[parse_command_args] missing option: '-R'\n");
goto PRINT_HELP_AND_EXIT;
}
parse_address_opt(opt_listen_addr, true);
parse_address_opt(opt_remote_addr, false);
return;
PRINT_HELP_AND_EXIT:
print_command_help();
exit(1);
}
int main(int argc, char *argv[]) {
signal(SIGPIPE, SIG_IGN);
setvbuf(stdout, NULL, _IOLBF, 256);
parse_command_args(argc, argv);
LOGINF("[main] udp listen addr: %s#%hu", g_listen_ipstr, g_listen_portno);
LOGINF("[main] tcp remote addr: %s#%hu", g_remote_ipstr, g_remote_portno);
IF_VERBOSE LOGINF("[main] verbose mode, affect performance");
g_evloop = uv_default_loop();
g_udp_server = &(uv_udp_t){0};
uv_udp_init(g_evloop, g_udp_server);
int retval = uv_udp_bind(g_udp_server, (void *)&g_listen_skaddr, 0);
if (retval < 0) {
LOGERR("[main] udp bind failed: (%d) %s", -retval, uv_strerror(retval));
return -retval;
}
uv_udp_recv_start(g_udp_server, udp_alloc_cb, udp_recv_cb);
uv_run(g_evloop, UV_RUN_DEFAULT);
return 0;
}
static void udp_alloc_cb(uv_handle_t *udp_server __attribute__((unused)), size_t sugsize __attribute__((unused)), uv_buf_t *uvbuf) {
uvbuf->base = malloc(DNS_PACKET_MAXSIZE + 2) + 2;
uvbuf->len = DNS_PACKET_MAXSIZE;
}
static void udp_recv_cb(uv_udp_t *udp_server __attribute__((unused)), ssize_t nread, const uv_buf_t *uvbuf, const skaddr_t *skaddr, unsigned flags) {
if (nread == 0) goto FREE_UVBUF;
if (nread < 0) {
LOGERR("[udp_recv_cb] udp recv failed: (%zd) %s", -nread, uv_strerror(nread));
goto FREE_UVBUF;
}
if (flags & UV_UDP_PARTIAL) {
LOGERR("[udp_recv_cb] received a corrupted(partial) udp packet");
goto FREE_UVBUF;
}
IF_VERBOSE {
char ipstr[IP6STRLEN]; portno_t portno;
if (skaddr->sa_family == AF_INET) {
parse_ipv4_addr((void *)skaddr, ipstr, &portno);
} else {
parse_ipv6_addr((void *)skaddr, ipstr, &portno);
}
LOGINF("[udp_recv_cb] recv %zd bytes data from %s#%hu", nread, ipstr, portno);
}
uv_tcp_t *tcp_client = malloc(sizeof(uv_tcp_t));
uv_tcp_init(g_evloop, tcp_client);
uv_tcp_nodelay(tcp_client, 1);
uint16_t *msglen_ptr = (void *)uvbuf->base - 2;
*msglen_ptr = htons(nread);
tcp_client->data = uvbuf->base - 2;
uv_connect_t *connreq = malloc(sizeof(uv_connect_t));
int retval = uv_tcp_connect(connreq, tcp_client, (void *)&g_remote_skaddr, tcp_connect_cb);
if (retval < 0) {
LOGERR("[udp_recv_cb] tcp connect failed: (%d) %s", -retval, uv_strerror(retval));
uv_close((void *)tcp_client, tcp_close_cb);
free(connreq);
return;
}
IF_VERBOSE LOGINF("[udp_recv_cb] try to connect to %s#%hu", g_remote_ipstr, g_remote_portno);
return;
FREE_UVBUF:
free(uvbuf->base - 2);
}
static void tcp_connect_cb(uv_connect_t *connreq, int status) {
// TODO
}
static void tcp_write_cb(uv_write_t *writereq, int status) {
// TODO
}
static void tcp_alloc_cb(uv_handle_t *tcp_client, size_t sugsize, uv_buf_t *uvbuf) {
// TODO
}
static void tcp_read_cb(uv_stream_t *tcp_client, ssize_t nread, const uv_buf_t *uvbuf) {
// TODO
}
static void tcp_close_cb(uv_handle_t *tcp_client) {
// TODO
}
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