void
connect_to_remote(struct remote_context *remote) {
remote->stage = XSTAGE_CONNECT;
remote->connect_req.data = remote;
int rc = uv_tcp_connect(&remote->connect_req, &remote->handle.tcp, &server_addr, remote_connect_cb);
if (rc) {
logger_log(LOG_ERR, "connect to server error: %s", uv_strerror(rc));
request_ack(remote->client, S5_REP_NETWORK_UNREACHABLE);
}
}
static void
remote_timer_expire(uv_timer_t *handle) {
struct remote_context *remote = handle->data;
struct client_context *client = remote->client;
if (verbose) {
char addrbuf[INET6_ADDRSTRLEN + 1] = {0};
uint16_t port = ip_name(&client->addr, addrbuf, sizeof addrbuf);
if (client->stage < XSTAGE_FORWARD) {
logger_log(LOG_WARNING, "%s:%d connection timeout", addrbuf, port);
} else {
logger_log(LOG_WARNING, "%s:%d <-> %s connection timeout", addrbuf, port, client->target_addr);
}
}
assert(client->stage != XSTAGE_TERMINATE);
request_ack(client, S5_REP_TTL_EXPIRED);
}
static void
remote_connect_cb(uv_connect_t *req, int status) {
struct remote_context *remote = (struct remote_context *)req->data;
struct client_context *client = remote->client;
if (status == 0) {
remote->stage = XSTAGE_FORWARD;
reset_timer(remote);
receive_from_client(client);
receive_from_remote(remote);
} else {
if (status != UV_ECANCELED) {
logger_log(LOG_ERR, "connect to server failed: %s", uv_strerror(status));
request_ack(client, S5_REP_HOST_UNREACHABLE);
}
}
}
static void
request_start(struct client_context *client, char *req_buf) {
struct socks5_request *req = (struct socks5_request *)req_buf;
struct remote_context *remote = client->remote;
assert(remote->stage == XSTAGE_FORWARD);
client->cmd = req->cmd;
if (req->cmd != S5_CMD_CONNECT && req->cmd != S5_CMD_UDP_ASSOCIATE) {
logger_log(LOG_ERR, "unsupported cmd: 0x%02x", req->cmd);
request_ack(client, S5_REP_CMD_NOT_SUPPORTED);
return;
}
if (req->cmd == S5_CMD_UDP_ASSOCIATE) {
request_ack(client, S5_REP_SUCCESSED);
return;
}
char buf[260] = {0};
size_t buflen;
uint16_t portlen = 2;
/*
*
* xsocks request
* +------+----------+----------+
* | ATYP | BND.ADDR | BND.PORT |
* +------+----------+----------+
* | 1 | Variable | 2 |
* +------+----------+----------+
*
*/
if (req->atyp == ATYP_IPV4) {
size_t in_addr_len = sizeof(struct in_addr);
buflen = sizeof(struct xsocks_request) + in_addr_len + portlen;
buf[0] = ATYP_IPV4;
memcpy(buf + 1, req->addr, in_addr_len);
memcpy(buf + 1 + in_addr_len, req->addr + in_addr_len, portlen);
uv_inet_ntop(AF_INET, (const void *)(req->addr), client->target_addr, INET_ADDRSTRLEN);
uint16_t port = read_size((uint8_t*)(req->addr + in_addr_len));
sprintf(client->target_addr, "%s:%u", client->target_addr, port);
} else if (req->atyp == ATYP_HOST) {
uint8_t namelen = *(uint8_t *)(req->addr);
if (namelen > 0xFF) {
logger_log(LOG_ERR, "unsupported address type: 0x%02x", req->atyp);
request_ack(client, S5_REP_ADDRESS_TYPE_NOT_SUPPORTED);
return;
}
buflen = sizeof(struct xsocks_request) + 1 + namelen + portlen;
buf[0] = ATYP_HOST;
memcpy(buf + 1, req->addr, 1 + namelen);
memcpy(buf + 1 + 1 + namelen, req->addr + 1 + namelen, portlen);
memcpy(client->target_addr, req->addr + 1, namelen);
uint16_t port = read_size((uint8_t*)(req->addr + 1 + namelen));
sprintf(client->target_addr, "%s:%u", client->target_addr, port);
} else if (req->atyp == ATYP_IPV6) {
size_t in6_addr_len = sizeof(struct in6_addr);
buflen = sizeof(struct xsocks_request) + in6_addr_len + portlen;
buf[0] = ATYP_IPV6;
memcpy(buf + 1, req->addr, in6_addr_len);
memcpy(buf + 1 + in6_addr_len, req->addr + in6_addr_len, portlen);
uv_inet_ntop(AF_INET6, (const void *)(req->addr), client->target_addr, INET_ADDRSTRLEN);
uint16_t port = read_size((uint8_t*)(req->addr + in6_addr_len));
sprintf(client->target_addr, "%s:%u", client->target_addr, port);
} else {
logger_log(LOG_ERR, "unsupported address type: 0x%02x", req->atyp);
request_ack(client, S5_REP_ADDRESS_TYPE_NOT_SUPPORTED);
return;
}
request_ack(client, S5_REP_SUCCESSED);
// TODO: handle UDP ASSOCIATE
if (req->cmd == S5_CMD_CONNECT) {
if (verbose) {
logger_log(LOG_INFO, "connect to %s", client->target_addr);
}
int clen = buflen + PRIMITIVE_BYTES;
uint8_t *c = client->buf + HEADER_BYTES;
int rc = crypto_encrypt(c, (uint8_t *)buf, buflen);
if (!rc) {
forward_to_remote(remote, c, clen);
}
}
}
