static void
client_recv_cb(uv_udp_t *handle, ssize_t nread, const uv_buf_t *buf, const struct sockaddr *addr, unsigned flags) {
struct server_context *server = container_of(handle, struct server_context, udp);
if (nread > 0) {
char key[KEY_BYTES + 1] = {0};
crypto_generickey((uint8_t *)key, sizeof(key) -1, (uint8_t*)addr, sizeof(*addr), NULL, 0);
struct client_context *client = NULL;
uv_mutex_lock(&mutex);
cache_lookup(cache, key, (void *)&client);
uv_mutex_unlock(&mutex);
if (client == NULL) {
client = new_client();
client->addr = *addr;
client->local_handle = handle;
memcpy(client->key, key, sizeof(key));
uv_timer_init(handle->loop, client->timer);
uv_udp_init(handle->loop, &client->server_handle);
client->server_handle.data = client;
uv_udp_recv_start(&client->server_handle, server_alloc_cb, server_recv_cb);
uv_mutex_lock(&mutex);
cache_insert(cache, client->key, (void *)client);
uv_mutex_unlock(&mutex);
}
int clen = nread + PRIMITIVE_BYTES + addrlen;
int mlen = nread + addrlen;
uint8_t *c = (uint8_t *)buf->base - PRIMITIVE_BYTES - addrlen;
uint8_t *m = (uint8_t *)buf->base - addrlen;
if (server->dest_addr->sa_family == AF_INET) {
struct sockaddr_in *addr = (struct sockaddr_in *)server->dest_addr;
m[0] = 1;
memcpy(m + 1, &addr->sin_addr, 4);
memcpy(m + 1 + 4, &addr->sin_port, 2);
} else {
struct sockaddr_in6 *addr = (struct sockaddr_in6 *)server->dest_addr;
m[0] = 4;
memcpy(m + 1, &addr->sin6_addr, 16);
memcpy(m + 1 + 16, &addr->sin6_port, 2);
}
int rc = crypto_encrypt(c, m, mlen);
if (!rc) {
reset_timer(client);
forward_to_server(server->server_addr, client, c, clen);
}
} else {
goto error;
}
return;
error:
free(buf->base - addrlen - PRIMITIVE_BYTES);
}
/*
*
* SOCKS5 UDP Request
* +----+------+------+----------+----------+----------+
* |RSV | FRAG | ATYP | DST.ADDR | DST.PORT | DATA |
* +----+------+------+----------+----------+----------+
* | 2 | 1 | 1 | Variable | 2 | Variable |
* +----+------+------+----------+----------+----------+
*
*/
static void
client_recv_cb(uv_udp_t *handle, ssize_t nread, const uv_buf_t *buf, const struct sockaddr *addr, unsigned flags) {
struct server_context *server = container_of(handle, struct server_context, udp);
if (nread > 0) {
uint8_t frag = buf->base[2];
if (frag) {
logger_log(LOG_ERR, "don't support udp dgram frag");
goto err;
}
char key[KEY_BYTES + 1] = {0};
crypto_generickey((uint8_t *)key, sizeof(key) -1, (uint8_t*)addr, sizeof(*addr), NULL, 0);
struct client_context *client = NULL;
uv_mutex_lock(&mutex);
cache_lookup(cache, key, (void *)&client);
uv_mutex_unlock(&mutex);
if (client == NULL) {
client = new_client();
client->addr = *addr;
client->local_handle = handle;
memcpy(client->key, key, sizeof(key));
uv_timer_init(handle->loop, client->timer);
uv_udp_init(handle->loop, &client->server_handle);
client->server_handle.data = client;
uv_udp_recv_start(&client->server_handle, server_alloc_cb, server_recv_cb);
uv_mutex_lock(&mutex);
cache_insert(cache, client->key, (void *)client);
uv_mutex_unlock(&mutex);
}
int clen = nread - 3 + PRIMITIVE_BYTES;
uint8_t *c = (uint8_t *)buf->base - PRIMITIVE_BYTES;
int rc = crypto_encrypt(c, (uint8_t*)buf->base + 3, nread - 3);
if (!rc) {
reset_timer(client);
forward_to_server(server->server_addr, client, c, clen);
}
} else {
goto err;
}
return;
err:
free(buf->base - PRIMITIVE_BYTES);
}
static void
poll_cb(uv_poll_t *watcher, int status, int events) {
char buffer[1024] = {0};
char control_buffer[64] = {0};
struct iovec iov[1];
struct msghdr msg;
struct sockaddr client_addr;
struct server_context *server = container_of(watcher, struct server_context, watcher);
if (status >= 0) {
msg.msg_name = &client_addr;
msg.msg_namelen = sizeof(client_addr);
msg.msg_control = control_buffer;
msg.msg_controllen = sizeof(control_buffer);
iov[0].iov_base = buffer;
iov[0].iov_len = sizeof(buffer);
msg.msg_iov = iov;
msg.msg_iovlen = 1;
int msglen = recvmsg(watcher->io_watcher.fd, &msg, 0);
if (msglen <= 0) {
logger_stderr("receive from client error: %s", strerror(errno));
}
struct sockaddr dest_addr;
if (getdestaddr(&msg, &dest_addr)) {
logger_stderr("can not get destination address");
}
int addrlen = dest_addr.sa_family == AF_INET ? IPV4_HEADER_LEN : IPV6_HEADER_LEN;
int mlen = addrlen + msglen;
int clen = PRIMITIVE_BYTES + mlen;
uint8_t *c = malloc(clen);
uint8_t *m = c + PRIMITIVE_BYTES;
/*
*
* xsocks UDP Request
* +------+----------+----------+----------+
* | ATYP | DST.ADDR | DST.PORT | DATA |
* +------+----------+----------+----------+
* | 1 | Variable | 2 | Variable |
* +------+----------+----------+----------+
*
*/
if (dest_addr.sa_family == AF_INET) {
struct sockaddr_in *addr = (struct sockaddr_in *)&dest_addr;
m[0] = ATYP_IPV4;
memcpy(m + 1, &addr->sin_addr, 4);
memcpy(m + 1 + 4, &addr->sin_port, 2);
} else {
struct sockaddr_in6 *addr = (struct sockaddr_in6 *)&dest_addr;
m[0] = ATYP_IPV6;
memcpy(m + 1, &addr->sin6_addr, 16);
memcpy(m + 1 + 16, &addr->sin6_port, 2);
}
memcpy(m + addrlen, buffer, msglen);
int rc = crypto_encrypt(c, m, mlen);
if (!rc) {
char key[KEY_BYTES + 1] = {0};
crypto_generickey((uint8_t *)key, sizeof(key) -1, (uint8_t *)&client_addr, sizeof(client_addr), NULL, 0);
struct client_context *client = NULL;
uv_mutex_lock(&mutex);
cache_lookup(cache, key, (void *)&client);
uv_mutex_unlock(&mutex);
if (client == NULL) {
client = new_client();
client->addr = client_addr;
memcpy(client->key, key, sizeof(key));
uv_timer_init(watcher->loop, client->timer);
uv_udp_init(watcher->loop, &client->server_handle);
client->server_handle.data = client;
uv_udp_recv_start(&client->server_handle, server_alloc_cb, server_recv_cb);
uv_mutex_lock(&mutex);
cache_insert(cache, client->key, (void *)client);
uv_mutex_unlock(&mutex);
}
reset_timer(client);
forward_to_server(server->server_addr, client, c, clen);
}
}
}
