static void remote_recv_cb(EV_P_ ev_io *w, int revents)
{
ssize_t r;
remote_ctx_t *remote_ctx = (remote_ctx_t *)w;
server_ctx_t *server_ctx = remote_ctx->server_ctx;
// server has been closed
if (server_ctx == NULL) {
LOGE("[udp] invalid server");
close_and_free_remote(EV_A_ remote_ctx);
return;
}
if (verbose) {
LOGI("[udp] remote receive a packet");
}
struct sockaddr_storage src_addr;
socklen_t src_addr_len = sizeof(src_addr);
memset(&src_addr, 0, src_addr_len);
buffer_t *buf = ss_malloc(sizeof(buffer_t));
balloc(buf, buf_size);
// recv
r = recvfrom(remote_ctx->fd, buf->array, buf_size, 0, (struct sockaddr *)&src_addr, &src_addr_len);
if (r == -1) {
// error on recv
// simply drop that packet
ERROR("[udp] remote_recv_recvfrom");
goto CLEAN_UP;
} else if (r > packet_size) {
LOGE("[udp] remote_recv_recvfrom fragmentation");
goto CLEAN_UP;
}
buf->len = r;
#ifdef MODULE_LOCAL
int err = ss_decrypt_all(buf, server_ctx->method, 0, buf_size);
if (err) {
// drop the packet silently
goto CLEAN_UP;
}
#ifdef MODULE_REDIR
struct sockaddr_storage dst_addr;
memset(&dst_addr, 0, sizeof(struct sockaddr_storage));
int len = parse_udprealy_header(buf->array, buf->len, NULL, NULL, NULL, &dst_addr);
if (dst_addr.ss_family != AF_INET && dst_addr.ss_family != AF_INET6) {
LOGI("[udp] ss-redir does not support domain name");
goto CLEAN_UP;
}
#else
int len = parse_udprealy_header(buf->array, buf->len, NULL, NULL, NULL, NULL);
#endif
if (len == 0) {
LOGI("[udp] error in parse header");
// error in parse header
goto CLEAN_UP;
}
// server may return using a different address type other than the type we
// have used during sending
#if defined(MODULE_TUNNEL) || defined(MODULE_REDIR)
// Construct packet
buf->len -= len;
memmove(buf->array, buf->array + len, buf->len);
#else
// Construct packet
brealloc(buf, buf->len + 3, buf_size);
memmove(buf->array + 3, buf->array, buf->len);
memset(buf->array, 0, 3);
buf->len += 3;
#endif
#endif
#ifdef MODULE_REMOTE
rx += buf->len;
char addr_header_buf[512];
char *addr_header = remote_ctx->addr_header;
int addr_header_len = remote_ctx->addr_header_len;
if (remote_ctx->af == AF_INET || remote_ctx->af == AF_INET6) {
addr_header_len = construct_udprealy_header(&src_addr, addr_header_buf);
addr_header = addr_header_buf;
}
// Construct packet
brealloc(buf, buf->len + addr_header_len, buf_size);
memmove(buf->array + addr_header_len, buf->array, buf->len);
memcpy(buf->array, addr_header, addr_header_len);
buf->len += addr_header_len;
int err = ss_encrypt_all(buf, server_ctx->method, 0, buf_size);
if (err) {
// drop the packet silently
goto CLEAN_UP;
}
#endif
if (buf->len > packet_size) {
LOGE("[udp] remote_recv_sendto fragmentation");
goto CLEAN_UP;
}
size_t remote_src_addr_len = get_sockaddr_len((struct sockaddr *)&remote_ctx->src_addr);
#ifdef MODULE_REDIR
size_t remote_dst_addr_len = get_sockaddr_len((struct sockaddr *)&dst_addr);
int src_fd = socket(remote_ctx->src_addr.ss_family, SOCK_DGRAM, 0);
if (src_fd < 0) {
ERROR("[udp] remote_recv_socket");
goto CLEAN_UP;
}
int opt = 1;
if (setsockopt(src_fd, SOL_IP, IP_TRANSPARENT, &opt, sizeof(opt))) {
ERROR("[udp] remote_recv_setsockopt");
close(src_fd);
goto CLEAN_UP;
}
if (setsockopt(src_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt))) {
ERROR("[udp] remote_recv_setsockopt");
close(src_fd);
goto CLEAN_UP;
}
#ifdef IP_TOS
// Set QoS flag
int tos = 46;
setsockopt(src_fd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
#endif
if (bind(src_fd, (struct sockaddr *)&dst_addr, remote_dst_addr_len) != 0) {
ERROR("[udp] remote_recv_bind");
close(src_fd);
goto CLEAN_UP;
}
int s = sendto(src_fd, buf->array, buf->len, 0,
(struct sockaddr *)&remote_ctx->src_addr, remote_src_addr_len);
if (s == -1) {
ERROR("[udp] remote_recv_sendto");
close(src_fd);
goto CLEAN_UP;
}
close(src_fd);
#else
int s = sendto(server_ctx->fd, buf->array, buf->len, 0,
(struct sockaddr *)&remote_ctx->src_addr, remote_src_addr_len);
if (s == -1) {
ERROR("[udp] remote_recv_sendto");
goto CLEAN_UP;
}
#endif
// handle the UDP packet successfully,
// triger the timer
ev_timer_again(EV_A_ & remote_ctx->watcher);
CLEAN_UP:
bfree(buf);
ss_free(buf);
}
static void server_recv_cb(EV_P_ ev_io *w, int revents)
{
server_ctx_t *server_ctx = (server_ctx_t *)w;
struct sockaddr_storage src_addr;
memset(&src_addr, 0, sizeof(struct sockaddr_storage));
buffer_t *buf = ss_malloc(sizeof(buffer_t));
balloc(buf, buf_size);
socklen_t src_addr_len = sizeof(struct sockaddr_storage);
unsigned int offset = 0;
#ifdef MODULE_REDIR
char control_buffer[64] = { 0 };
struct msghdr msg;
struct iovec iov[1];
struct sockaddr_storage dst_addr;
memset(&dst_addr, 0, sizeof(struct sockaddr_storage));
msg.msg_name = &src_addr;
msg.msg_namelen = src_addr_len;
msg.msg_control = control_buffer;
msg.msg_controllen = sizeof(control_buffer);
iov[0].iov_base = buf->array;
iov[0].iov_len = buf_size;
msg.msg_iov = iov;
msg.msg_iovlen = 1;
buf->len = recvmsg(server_ctx->fd, &msg, 0);
if (buf->len == -1) {
ERROR("[udp] server_recvmsg");
goto CLEAN_UP;
} else if (buf->len > packet_size) {
ERROR("[udp] UDP server_recv_recvmsg fragmentation");
goto CLEAN_UP;
}
if (get_dstaddr(&msg, &dst_addr)) {
LOGE("[udp] unable to get dest addr");
goto CLEAN_UP;
}
src_addr_len = msg.msg_namelen;
#else
ssize_t r;
r = recvfrom(server_ctx->fd, buf->array, buf_size,
0, (struct sockaddr *)&src_addr, &src_addr_len);
if (r == -1) {
// error on recv
// simply drop that packet
ERROR("[udp] server_recv_recvfrom");
goto CLEAN_UP;
} else if (r > packet_size) {
ERROR("[udp] server_recv_recvfrom fragmentation");
goto CLEAN_UP;
}
buf->len = r;
#endif
if (verbose) {
LOGI("[udp] server receive a packet");
}
#ifdef MODULE_REMOTE
tx += buf->len;
int err = ss_decrypt_all(buf, server_ctx->method, server_ctx->auth, buf_size);
if (err) {
// drop the packet silently
goto CLEAN_UP;
}
#endif
#ifdef MODULE_LOCAL
#if !defined(MODULE_TUNNEL) && !defined(MODULE_REDIR)
uint8_t frag = *(uint8_t *)(buf->array + 2);
offset += 3;
#endif
#endif
/*
*
* SOCKS5 UDP Request
* +----+------+------+----------+----------+----------+
* |RSV | FRAG | ATYP | DST.ADDR | DST.PORT | DATA |
* +----+------+------+----------+----------+----------+
* | 2 | 1 | 1 | Variable | 2 | Variable |
* +----+------+------+----------+----------+----------+
*
* SOCKS5 UDP Response
* +----+------+------+----------+----------+----------+
* |RSV | FRAG | ATYP | DST.ADDR | DST.PORT | DATA |
* +----+------+------+----------+----------+----------+
* | 2 | 1 | 1 | Variable | 2 | Variable |
* +----+------+------+----------+----------+----------+
*
* shadowsocks UDP Request (before encrypted)
* +------+----------+----------+----------+-------------+
* | ATYP | DST.ADDR | DST.PORT | DATA | HMAC-SHA1 |
* +------+----------+----------+----------+-------------+
* | 1 | Variable | 2 | Variable | 10 |
* +------+----------+----------+----------+-------------+
*
* If ATYP & ONETIMEAUTH_FLAG(0x10) == 1, Authentication (HMAC-SHA1) is enabled.
*
* The key of HMAC-SHA1 is (IV + KEY) and the input is the whole packet.
* The output of HMAC-SHA is truncated to 10 bytes (leftmost bits).
*
* shadowsocks UDP Response (before encrypted)
* +------+----------+----------+----------+
* | ATYP | DST.ADDR | DST.PORT | DATA |
* +------+----------+----------+----------+
* | 1 | Variable | 2 | Variable |
* +------+----------+----------+----------+
*
* shadowsocks UDP Request and Response (after encrypted)
* +-------+--------------+
* | IV | PAYLOAD |
* +-------+--------------+
* | Fixed | Variable |
* +-------+--------------+
*
*/
#ifdef MODULE_REDIR
char addr_header[512] = { 0 };
int addr_header_len = construct_udprealy_header(&dst_addr, addr_header);
if (addr_header_len == 0) {
LOGE("[udp] failed to parse tproxy addr");
goto CLEAN_UP;
}
// reconstruct the buffer
brealloc(buf, buf->len + addr_header_len, buf_size);
memmove(buf->array + addr_header_len, buf->array, buf->len);
memcpy(buf->array, addr_header, addr_header_len);
buf->len += addr_header_len;
#elif MODULE_TUNNEL
char addr_header[512] = { 0 };
char *host = server_ctx->tunnel_addr.host;
char *port = server_ctx->tunnel_addr.port;
uint16_t port_num = (uint16_t)atoi(port);
uint16_t port_net_num = htons(port_num);
int addr_header_len = 0;
struct cork_ip ip;
if (cork_ip_init(&ip, host) != -1) {
if (ip.version == 4) {
// send as IPv4
struct in_addr host_addr;
int host_len = sizeof(struct in_addr);
if (dns_pton(AF_INET, host, &host_addr) == -1) {
FATAL("IP parser error");
}
addr_header[addr_header_len++] = 1;
memcpy(addr_header + addr_header_len, &host_addr, host_len);
addr_header_len += host_len;
} else if (ip.version == 6) {
// send as IPv6
struct in6_addr host_addr;
int host_len = sizeof(struct in6_addr);
if (dns_pton(AF_INET6, host, &host_addr) == -1) {
FATAL("IP parser error");
}
addr_header[addr_header_len++] = 4;
memcpy(addr_header + addr_header_len, &host_addr, host_len);
addr_header_len += host_len;
} else {
FATAL("IP parser error");
}
} else {
// send as domain
int host_len = strlen(host);
addr_header[addr_header_len++] = 3;
addr_header[addr_header_len++] = host_len;
memcpy(addr_header + addr_header_len, host, host_len);
addr_header_len += host_len;
}
memcpy(addr_header + addr_header_len, &port_net_num, 2);
addr_header_len += 2;
// reconstruct the buffer
brealloc(buf, buf->len + addr_header_len, buf_size);
memmove(buf->array + addr_header_len, buf->array, buf->len);
memcpy(buf->array, addr_header, addr_header_len);
buf->len += addr_header_len;
#else
char host[257] = { 0 };
char port[64] = { 0 };
struct sockaddr_storage dst_addr;
memset(&dst_addr, 0, sizeof(struct sockaddr_storage));
int addr_header_len = parse_udprealy_header(buf->array + offset, buf->len - offset,
&server_ctx->auth, host, port,
&dst_addr);
if (addr_header_len == 0) {
// error in parse header
goto CLEAN_UP;
}
char *addr_header = buf->array + offset;
#endif
#ifdef MODULE_LOCAL
char *key = hash_key(server_ctx->remote_addr->sa_family, &src_addr);
#else
char *key = hash_key(dst_addr.ss_family, &src_addr);
#endif
struct cache *conn_cache = server_ctx->conn_cache;
remote_ctx_t *remote_ctx = NULL;
cache_lookup(conn_cache, key, HASH_KEY_LEN, (void *)&remote_ctx);
if (remote_ctx != NULL) {
if (sockaddr_cmp(&src_addr, &remote_ctx->src_addr, sizeof(src_addr))) {
remote_ctx = NULL;
}
}
// reset the timer
if (remote_ctx != NULL) {
ev_timer_again(EV_A_ & remote_ctx->watcher);
}
if (remote_ctx == NULL) {
if (verbose) {
#ifdef MODULE_REDIR
char src[SS_ADDRSTRLEN];
char dst[SS_ADDRSTRLEN];
strcpy(src, get_addr_str((struct sockaddr *)&src_addr));
strcpy(dst, get_addr_str((struct sockaddr *)&dst_addr));
LOGI("[udp] cache miss: %s <-> %s", dst, src);
#else
LOGI("[udp] cache miss: %s:%s <-> %s", host, port,
get_addr_str((struct sockaddr *)&src_addr));
#endif
}
} else {
if (verbose) {
#ifdef MODULE_REDIR
char src[SS_ADDRSTRLEN];
char dst[SS_ADDRSTRLEN];
strcpy(src, get_addr_str((struct sockaddr *)&src_addr));
strcpy(dst, get_addr_str((struct sockaddr *)&dst_addr));
LOGI("[udp] cache hit: %s <-> %s", dst, src);
#else
LOGI("[udp] cache hit: %s:%s <-> %s", host, port,
get_addr_str((struct sockaddr *)&src_addr));
#endif
}
}
#ifdef MODULE_LOCAL
#if !defined(MODULE_TUNNEL) && !defined(MODULE_REDIR)
if (frag) {
LOGE("[udp] drop a message since frag is not 0, but %d", frag);
goto CLEAN_UP;
}
#endif
const struct sockaddr *remote_addr = server_ctx->remote_addr;
const int remote_addr_len = server_ctx->remote_addr_len;
if (remote_ctx == NULL) {
// Bind to any port
int remotefd = create_remote_socket(remote_addr->sa_family == AF_INET6);
if (remotefd < 0) {
ERROR("[udp] udprelay bind() error");
goto CLEAN_UP;
}
setnonblocking(remotefd);
#ifdef SO_NOSIGPIPE
set_nosigpipe(remotefd);
#endif
#ifdef IP_TOS
// Set QoS flag
int tos = 46;
setsockopt(remotefd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
#endif
#ifdef SET_INTERFACE
if (server_ctx->iface) {
if (setinterface(remotefd, server_ctx->iface) == -1)
ERROR("setinterface");
}
#endif
#ifdef ANDROID
if (vpn) {
if (protect_socket(remotefd) == -1) {
ERROR("protect_socket");
close(remotefd);
goto CLEAN_UP;
}
}
#endif
// Init remote_ctx
remote_ctx = new_remote(remotefd, server_ctx);
remote_ctx->src_addr = src_addr;
remote_ctx->af = remote_addr->sa_family;
remote_ctx->addr_header_len = addr_header_len;
memcpy(remote_ctx->addr_header, addr_header, addr_header_len);
// Add to conn cache
cache_insert(conn_cache, key, HASH_KEY_LEN, (void *)remote_ctx);
// Start remote io
ev_io_start(EV_A_ & remote_ctx->io);
ev_timer_start(EV_A_ & remote_ctx->watcher);
}
if (offset > 0) {
buf->len -= offset;
memmove(buf->array, buf->array + offset, buf->len);
}
if (server_ctx->auth) {
buf->array[0] |= ONETIMEAUTH_FLAG;
}
int err = ss_encrypt_all(buf, server_ctx->method, server_ctx->auth, buf_size);
if (err) {
// drop the packet silently
goto CLEAN_UP;
}
if (buf->len > packet_size) {
LOGE("[udp] server_recv_sendto fragmentation");
goto CLEAN_UP;
}
int s = sendto(remote_ctx->fd, buf->array, buf->len, 0, remote_addr, remote_addr_len);
if (s == -1) {
ERROR("[udp] server_recv_sendto");
}
#else
int cache_hit = 0;
int need_query = 0;
if (buf->len - addr_header_len > packet_size) {
LOGE("[udp] server_recv_sendto fragmentation");
goto CLEAN_UP;
}
if (remote_ctx != NULL) {
cache_hit = 1;
// detect destination mismatch
if (remote_ctx->addr_header_len != addr_header_len
|| memcmp(addr_header, remote_ctx->addr_header, addr_header_len) != 0) {
if (dst_addr.ss_family != AF_INET && dst_addr.ss_family != AF_INET6) {
need_query = 1;
}
} else {
memcpy(&dst_addr, &remote_ctx->dst_addr, sizeof(struct sockaddr_storage));
}
} else {
if (dst_addr.ss_family == AF_INET || dst_addr.ss_family == AF_INET6) {
int remotefd = create_remote_socket(dst_addr.ss_family == AF_INET6);
if (remotefd != -1) {
setnonblocking(remotefd);
#ifdef SO_BROADCAST
set_broadcast(remotefd);
#endif
#ifdef SO_NOSIGPIPE
set_nosigpipe(remotefd);
#endif
#ifdef IP_TOS
// Set QoS flag
int tos = 46;
setsockopt(remotefd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
#endif
#ifdef SET_INTERFACE
if (server_ctx->iface) {
if (setinterface(remotefd, server_ctx->iface) == -1)
ERROR("setinterface");
}
#endif
remote_ctx = new_remote(remotefd, server_ctx);
remote_ctx->src_addr = src_addr;
remote_ctx->server_ctx = server_ctx;
remote_ctx->addr_header_len = addr_header_len;
memcpy(remote_ctx->addr_header, addr_header, addr_header_len);
memcpy(&remote_ctx->dst_addr, &dst_addr, sizeof(struct sockaddr_storage));
} else {
ERROR("[udp] bind() error");
goto CLEAN_UP;
}
}
}
if (remote_ctx != NULL && !need_query) {
size_t addr_len = get_sockaddr_len((struct sockaddr *)&dst_addr);
int s = sendto(remote_ctx->fd, buf->array + addr_header_len,
buf->len - addr_header_len, 0,
(struct sockaddr *)&dst_addr, addr_len);
if (s == -1) {
ERROR("[udp] sendto_remote");
if (!cache_hit) {
close_and_free_remote(EV_A_ remote_ctx);
}
} else {
if (!cache_hit) {
// Add to conn cache
remote_ctx->af = dst_addr.ss_family;
char *key = hash_key(remote_ctx->af, &remote_ctx->src_addr);
cache_insert(server_ctx->conn_cache, key, HASH_KEY_LEN, (void *)remote_ctx);
ev_io_start(EV_A_ & remote_ctx->io);
ev_timer_start(EV_A_ & remote_ctx->watcher);
}
}
} else {
struct addrinfo hints;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_protocol = IPPROTO_UDP;
struct query_ctx *query_ctx = new_query_ctx(buf->array + addr_header_len,
buf->len - addr_header_len);
query_ctx->server_ctx = server_ctx;
query_ctx->addr_header_len = addr_header_len;
query_ctx->src_addr = src_addr;
memcpy(query_ctx->addr_header, addr_header, addr_header_len);
if (need_query) {
query_ctx->remote_ctx = remote_ctx;
}
struct ResolvQuery *query = resolv_query(host, query_resolve_cb,
NULL, query_ctx, htons(atoi(port)));
if (query == NULL) {
ERROR("[udp] unable to create DNS query");
close_and_free_query(EV_A_ query_ctx);
goto CLEAN_UP;
}
query_ctx->query = query;
}
#endif
CLEAN_UP:
bfree(buf);
ss_free(buf);
}
static void server_recv_cb (EV_P_ ev_io *w, int revents)
{
struct server_ctx *server_ctx = (struct server_ctx *)w;
struct sockaddr src_addr;
char *buf = malloc(BUF_SIZE);
socklen_t addr_len = sizeof(src_addr);
unsigned int offset = 0;
ssize_t buf_len = recvfrom(server_ctx->fd, buf, BUF_SIZE, 0, &src_addr, &addr_len);
if (buf_len == -1)
{
// error on recv
// simply drop that packet
if (verbose)
{
ERROR("udprelay_server_recvfrom");
}
goto CLEAN_UP;
}
if (verbose)
{
LOGD("[udp] server receive a packet.");
}
#ifdef UDPRELAY_REMOTE
buf = ss_decrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method);
#endif
#ifdef UDPRELAY_LOCAL
uint8_t frag = *(uint8_t*)(buf + 2);
offset += 3;
#endif
/*
*
* SOCKS5 UDP Request
* +----+------+------+----------+----------+----------+
* |RSV | FRAG | ATYP | DST.ADDR | DST.PORT | DATA |
* +----+------+------+----------+----------+----------+
* | 2 | 1 | 1 | Variable | 2 | Variable |
* +----+------+------+----------+----------+----------+
*
* SOCKS5 UDP Response
* +----+------+------+----------+----------+----------+
* |RSV | FRAG | ATYP | DST.ADDR | DST.PORT | DATA |
* +----+------+------+----------+----------+----------+
* | 2 | 1 | 1 | Variable | 2 | Variable |
* +----+------+------+----------+----------+----------+
*
* shadowsocks UDP Request (before encrypted)
* +------+----------+----------+----------+
* | ATYP | DST.ADDR | DST.PORT | DATA |
* +------+----------+----------+----------+
* | 1 | Variable | 2 | Variable |
* +------+----------+----------+----------+
*
* shadowsocks UDP Response (before encrypted)
* +------+----------+----------+----------+
* | ATYP | DST.ADDR | DST.PORT | DATA |
* +------+----------+----------+----------+
* | 1 | Variable | 2 | Variable |
* +------+----------+----------+----------+
*
* shadowsocks UDP Request and Response (after encrypted)
* +-------+--------------+
* | IV | PAYLOAD |
* +-------+--------------+
* | Fixed | Variable |
* +-------+--------------+
*
*/
char host[256] = {0};
char port[64] = {0};
int addr_header_len = parse_udprealy_header(buf + offset,
buf_len - offset, host, port);
if (addr_header_len == 0)
{
// error in parse header
goto CLEAN_UP;
}
char *addr_header = buf + offset;
char *key = hash_key(addr_header, addr_header_len, &src_addr);
struct cache *conn_cache = server_ctx->conn_cache;
struct remote_ctx *remote_ctx = NULL;
cache_lookup(conn_cache, key, (void*)&remote_ctx);
if (remote_ctx == NULL)
{
if (verbose)
{
LOGD("[udp] cache missed: %s:%s", host, port);
}
}
else
{
if (verbose)
{
LOGD("[udp] cache hit: %s:%s", host, port);
}
}
#ifdef UDPRELAY_LOCAL
if (frag)
{
LOGE("drop a message since frag is not 0, but %d", frag);
goto CLEAN_UP;
}
if (remote_ctx == NULL)
{
struct addrinfo hints;
struct addrinfo *result;
memset(&hints, 0, sizeof(struct addrinfo));
hints.ai_family = AF_UNSPEC; /* Return IPv4 and IPv6 choices */
hints.ai_socktype = SOCK_DGRAM; /* We want a UDP socket */
int s = getaddrinfo(server_ctx->remote_host, server_ctx->remote_port,
&hints, &result);
if (s != 0 || result == NULL)
{
LOGE("getaddrinfo: %s", gai_strerror(s));
goto CLEAN_UP;
}
// Bind to any port
int remotefd = create_remote_socket(result->ai_family == AF_INET6);
if (remotefd < 0)
{
ERROR("udprelay bind() error..");
// remember to free addrinfo
freeaddrinfo(result);
goto CLEAN_UP;
}
setnonblocking(remotefd);
#ifdef SO_NOSIGPIPE
int opt = 1;
setsockopt(remotefd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
#endif
#ifdef SET_INTERFACE
if (server_ctx->iface)
setinterface(remotefd, server_ctx->iface);
#endif
// Init remote_ctx
remote_ctx = new_remote(remotefd, server_ctx);
remote_ctx->src_addr = src_addr;
remote_ctx->dst_addr = *result->ai_addr;
remote_ctx->addr_header_len = addr_header_len;
memcpy(remote_ctx->addr_header, addr_header, addr_header_len);
// Add to conn cache
cache_insert(conn_cache, key, (void *)remote_ctx);
// Start remote io
ev_io_start(EV_A_ &remote_ctx->io);
// clean up
freeaddrinfo(result);
}
buf_len -= offset;
memmove(buf, buf + offset, buf_len);
buf = ss_encrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method);
int s = sendto(remote_ctx->fd, buf, buf_len, 0, &remote_ctx->dst_addr, sizeof(remote_ctx->dst_addr));
if (s == -1)
{
ERROR("udprelay_sendto_remote");
}
#else
if (remote_ctx == NULL)
{
struct addrinfo hints;
asyncns_query_t *query;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
query = asyncns_getaddrinfo(server_ctx->asyncns,
host, port, &hints);
if (query == NULL)
{
ERROR("udp_asyncns_getaddrinfo");
goto CLEAN_UP;
}
struct query_ctx *query_ctx = new_query_ctx(query, buf + addr_header_len,
buf_len - addr_header_len);
query_ctx->server_ctx = server_ctx;
query_ctx->addr_header_len = addr_header_len;
query_ctx->src_addr = src_addr;
memcpy(query_ctx->addr_header, addr_header, addr_header_len);
ev_timer_start(EV_A_ &query_ctx->watcher);
}
else
{
int s = sendto(remote_ctx->fd, buf + addr_header_len,
buf_len - addr_header_len, 0, &remote_ctx->dst_addr, sizeof(remote_ctx->dst_addr));
if (s == -1)
{
ERROR("udprelay_sendto_remote");
}
}
#endif
CLEAN_UP:
free(buf);
}
static void remote_recv_cb (EV_P_ ev_io *w, int revents)
{
struct remote_ctx *remote_ctx = (struct remote_ctx *)w;
struct server_ctx *server_ctx = remote_ctx->server_ctx;
// server has been closed
if (server_ctx == NULL)
{
LOGE("invalid server.");
close_and_free_remote(EV_A_ remote_ctx);
return;
}
if (verbose)
{
LOGD("[udp] remote receive a packet");
}
// triger the timer
ev_timer_again(EV_A_ &remote_ctx->watcher);
struct sockaddr src_addr;
socklen_t addr_len = sizeof(src_addr);
unsigned int addr_header_len = remote_ctx->addr_header_len;
char *buf = malloc(BUF_SIZE);
// recv
ssize_t buf_len = recvfrom(remote_ctx->fd, buf, BUF_SIZE, 0, &src_addr, &addr_len);
if (buf_len == -1)
{
// error on recv
// simply drop that packet
if (verbose)
{
ERROR("udprelay_server_recvfrom");
}
goto CLEAN_UP;
}
#ifdef UDPRELAY_LOCAL
buf = ss_decrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method);
int len = parse_udprealy_header(buf, buf_len, NULL, NULL);
if (len == 0 || len != addr_header_len)
{
// error in parse header
goto CLEAN_UP;
}
// Construct packet
char *tmpbuf = malloc(buf_len + 3);
memset(tmpbuf, 0, 3);
memcpy(tmpbuf + 3, buf, buf_len);
free(buf);
buf = tmpbuf;
buf_len += 3;
#endif
#ifdef UDPRELAY_REMOTE
// Construct packet
char *tmpbuf = malloc(buf_len + addr_header_len);
memcpy(tmpbuf, remote_ctx->addr_header, addr_header_len);
memcpy(tmpbuf + addr_header_len, buf, buf_len);
free(buf);
buf = tmpbuf;
buf_len += addr_header_len;
buf = ss_encrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method);
#endif
int s = sendto(server_ctx->fd, buf, buf_len, 0, &remote_ctx->src_addr, sizeof(remote_ctx->src_addr));
if (s == -1)
{
ERROR("udprelay_sendto_local");
}
CLEAN_UP:
free(buf);
}
static void remote_recv_cb(EV_P_ ev_io *w, int revents)
{
struct remote_ctx *remote_ctx = (struct remote_ctx *)w;
struct server_ctx *server_ctx = remote_ctx->server_ctx;
// server has been closed
if (server_ctx == NULL) {
LOGE("[udp] invalid server");
close_and_free_remote(EV_A_ remote_ctx);
return;
}
if (verbose) {
LOGI("[udp] remote receive a packet");
}
struct sockaddr_storage src_addr;
socklen_t src_addr_len = sizeof(src_addr);
memset(&src_addr, 0, src_addr_len);
char *buf = malloc(BUF_SIZE);
// recv
ssize_t buf_len = recvfrom(remote_ctx->fd, buf, BUF_SIZE, 0, (struct sockaddr *)&src_addr, &src_addr_len);
if (buf_len == -1) {
// error on recv
// simply drop that packet
if (verbose) {
ERROR("[udp] server_recvfrom");
}
goto CLEAN_UP;
}
#ifdef UDPRELAY_LOCAL
buf = ss_decrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method);
if (buf == NULL) {
if (verbose) {
ERROR("[udp] server_ss_decrypt_all");
}
goto CLEAN_UP;
}
#ifdef UDPRELAY_REDIR
struct sockaddr_storage dst_addr;
memset(&dst_addr, 0, sizeof(struct sockaddr_storage));
int len = parse_udprealy_header(buf, buf_len, NULL, NULL, &dst_addr);
if (dst_addr.ss_family != AF_INET && dst_addr.ss_family != AF_INET6) {
LOGI("[udp] ss-redir does not support domain name");
goto CLEAN_UP;
}
#else
int len = parse_udprealy_header(buf, buf_len, NULL, NULL, NULL);
#endif
if (len == 0) {
LOGI("[udp] error in parse header");
// error in parse header
goto CLEAN_UP;
}
// server may return using a different address type other than the type we
// have used during sending
#if defined(UDPRELAY_TUNNEL) || defined(UDPRELAY_REDIR)
// Construct packet
buf_len -= len;
memmove(buf, buf + len, buf_len);
#else
// Construct packet
buf = realloc(buf, buf_len + 3);
memmove(buf + 3, buf, buf_len);
memset(buf, 0, 3);
buf_len += 3;
#endif
#endif
#ifdef UDPRELAY_REMOTE
char addr_header_buf[256];
char *addr_header = remote_ctx->addr_header;
int addr_header_len = remote_ctx->addr_header_len;
if (remote_ctx->af == AF_INET || remote_ctx->af == AF_INET6) {
addr_header_len = construct_udprealy_header(&src_addr, addr_header_buf);
addr_header = addr_header_buf;
}
// Construct packet
buf = realloc(buf, buf_len + addr_header_len);
memmove(buf + addr_header_len, buf, buf_len);
memcpy(buf, addr_header, addr_header_len);
buf_len += addr_header_len;
buf = ss_encrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method);
#endif
size_t remote_src_addr_len = get_sockaddr_len((struct sockaddr *)&remote_ctx->src_addr);
#ifdef UDPRELAY_REDIR
size_t remote_dst_addr_len = get_sockaddr_len((struct sockaddr *)&dst_addr);
int src_fd = socket(remote_ctx->src_addr.ss_family, SOCK_DGRAM, 0);
if (src_fd < 0) {
ERROR("[udp] remote_recv_socket");
goto CLEAN_UP;
}
int opt = 1;
if (setsockopt(src_fd, SOL_IP, IP_TRANSPARENT, &opt, sizeof(opt))) {
ERROR("[udp] remote_recv_setsockopt");
close(src_fd);
goto CLEAN_UP;
}
if (setsockopt(src_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt))) {
ERROR("[udp] remote_recv_setsockopt");
close(src_fd);
goto CLEAN_UP;
}
if (bind(src_fd, (struct sockaddr *)&dst_addr, remote_dst_addr_len) != 0) {
ERROR("[udp] remote_recv_bind");
close(src_fd);
goto CLEAN_UP;
}
int s = sendto(src_fd, buf, buf_len, 0,
(struct sockaddr *)&remote_ctx->src_addr, remote_src_addr_len);
if (s == -1) {
ERROR("[udp] remote_recv_sendto");
close(src_fd);
goto CLEAN_UP;
}
close(src_fd);
#else
int s = sendto(server_ctx->fd, buf, buf_len, 0,
(struct sockaddr *)&remote_ctx->src_addr, remote_src_addr_len);
if (s == -1) {
ERROR("[udp] remote_recv_sendto");
goto CLEAN_UP;
}
#endif
// handle the UDP packet sucessfully,
// triger the timer
ev_timer_again(EV_A_ & remote_ctx->watcher);
CLEAN_UP:
free(buf);
}
static void server_recv_cb(EV_P_ ev_io *w, int revents)
{
struct server_ctx *server_ctx = (struct server_ctx *)w;
struct sockaddr_storage src_addr;
char *buf = malloc(BUF_SIZE);
socklen_t src_addr_len = sizeof(struct sockaddr_storage);
unsigned int offset = 0;
ssize_t buf_len =
recvfrom(server_ctx->fd, buf, BUF_SIZE, 0, (struct sockaddr *)&src_addr,
&src_addr_len);
if (buf_len == -1) {
// error on recv
// simply drop that packet
if (verbose) {
ERROR("[udp] server_recvfrom");
}
goto CLEAN_UP;
}
if (verbose) {
LOGD("[udp] server receive a packet.");
}
#ifdef UDPRELAY_REMOTE
buf = ss_decrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method);
if (buf == NULL) {
if (verbose) {
ERROR("[udp] server_ss_decrypt_all");
}
goto CLEAN_UP;
}
#endif
#ifdef UDPRELAY_LOCAL
#ifndef UDPRELAY_TUNNEL
uint8_t frag = *(uint8_t *)(buf + 2);
offset += 3;
#endif
#endif
/*
*
* SOCKS5 UDP Request
* +----+------+------+----------+----------+----------+
* |RSV | FRAG | ATYP | DST.ADDR | DST.PORT | DATA |
* +----+------+------+----------+----------+----------+
* | 2 | 1 | 1 | Variable | 2 | Variable |
* +----+------+------+----------+----------+----------+
*
* SOCKS5 UDP Response
* +----+------+------+----------+----------+----------+
* |RSV | FRAG | ATYP | DST.ADDR | DST.PORT | DATA |
* +----+------+------+----------+----------+----------+
* | 2 | 1 | 1 | Variable | 2 | Variable |
* +----+------+------+----------+----------+----------+
*
* shadowsocks UDP Request (before encrypted)
* +------+----------+----------+----------+
* | ATYP | DST.ADDR | DST.PORT | DATA |
* +------+----------+----------+----------+
* | 1 | Variable | 2 | Variable |
* +------+----------+----------+----------+
*
* shadowsocks UDP Response (before encrypted)
* +------+----------+----------+----------+
* | ATYP | DST.ADDR | DST.PORT | DATA |
* +------+----------+----------+----------+
* | 1 | Variable | 2 | Variable |
* +------+----------+----------+----------+
*
* shadowsocks UDP Request and Response (after encrypted)
* +-------+--------------+
* | IV | PAYLOAD |
* +-------+--------------+
* | Fixed | Variable |
* +-------+--------------+
*
*/
#ifdef UDPRELAY_TUNNEL
char addr_header[256] = { 0 };
char * host = server_ctx->tunnel_addr.host;
char * port = server_ctx->tunnel_addr.port;
int host_len = strlen(host);
uint16_t port_num = (uint16_t)atoi(port);
uint16_t port_net_num = htons(port_num);
int addr_header_len = 2 + host_len + 2;
// initialize the addr header
addr_header[0] = 3;
addr_header[1] = host_len;
memcpy(addr_header + 2, host, host_len);
memcpy(addr_header + 2 + host_len, &port_net_num, 2);
// reconstruct the buffer
char *tmp = malloc(buf_len + addr_header_len);
memcpy(tmp, addr_header, addr_header_len);
memcpy(tmp + addr_header_len, buf, buf_len);
free(buf);
buf = tmp;
buf_len += addr_header_len;
#else
char host[256] = { 0 };
char port[64] = { 0 };
int addr_header_len = parse_udprealy_header(buf + offset,
buf_len - offset, host, port);
if (addr_header_len == 0) {
// error in parse header
goto CLEAN_UP;
}
char *addr_header = buf + offset;
#endif
char *key = hash_key(addr_header, addr_header_len, &src_addr);
struct cache *conn_cache = server_ctx->conn_cache;
struct remote_ctx *remote_ctx = NULL;
cache_lookup(conn_cache, key, (void *)&remote_ctx);
if (remote_ctx != NULL) {
if (memcmp(&src_addr, &remote_ctx->src_addr, sizeof(src_addr))
|| strcmp(addr_header, remote_ctx->addr_header) != 0) {
remote_ctx = NULL;
}
}
if (remote_ctx == NULL) {
if (verbose) {
LOGD("[udp] cache missed: %s:%s <-> %s", host, port,
get_addr_str((struct sockaddr *)&src_addr));
}
} else {
if (verbose) {
LOGD("[udp] cache hit: %s:%s <-> %s", host, port,
get_addr_str((struct sockaddr *)&src_addr));
}
}
#ifdef UDPRELAY_LOCAL
#ifndef UDPRELAY_TUNNEL
if (frag) {
LOGE("[udp] drop a message since frag is not 0, but %d", frag);
goto CLEAN_UP;
}
#endif
if (remote_ctx == NULL) {
struct addrinfo hints;
struct addrinfo *result;
memset(&hints, 0, sizeof(struct addrinfo));
hints.ai_family = AF_UNSPEC; /* Return IPv4 and IPv6 choices */
hints.ai_socktype = SOCK_DGRAM; /* We want a UDP socket */
int s = getaddrinfo(server_ctx->remote_host, server_ctx->remote_port,
&hints, &result);
if (s != 0 || result == NULL) {
LOGE("[udp] getaddrinfo: %s", gai_strerror(s));
goto CLEAN_UP;
}
// Bind to any port
int remotefd = create_remote_socket(result->ai_family == AF_INET6);
if (remotefd < 0) {
ERROR("[udp] udprelay bind() error..");
// remember to free addrinfo
freeaddrinfo(result);
goto CLEAN_UP;
}
setnonblocking(remotefd);
#ifdef SO_NOSIGPIPE
set_nosigpipe(remotefd);
#endif
#ifdef SET_INTERFACE
if (server_ctx->iface) {
setinterface(remotefd, server_ctx->iface);
}
#endif
// Init remote_ctx
remote_ctx = new_remote(remotefd, server_ctx);
remote_ctx->src_addr = src_addr;
remote_ctx->dst_addr = *((struct sockaddr_storage *)result->ai_addr);
remote_ctx->addr_header_len = addr_header_len;
memcpy(remote_ctx->addr_header, addr_header, addr_header_len);
// Add to conn cache
cache_insert(conn_cache, key, (void *)remote_ctx);
// Start remote io
ev_io_start(EV_A_ & remote_ctx->io);
// clean up
freeaddrinfo(result);
}
if (offset > 0) {
buf_len -= offset;
memmove(buf, buf + offset, buf_len);
}
buf = ss_encrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method);
size_t addr_len = sizeof(struct sockaddr_in);
if (remote_ctx->dst_addr.ss_family == AF_INET6) {
addr_len = sizeof(struct sockaddr_in6);
}
int s = sendto(remote_ctx->fd, buf, buf_len, 0,
(struct sockaddr *)&remote_ctx->dst_addr, addr_len);
if (s == -1) {
ERROR("[udp] sendto_remote");
}
#else
if (remote_ctx == NULL) {
struct addrinfo hints;
asyncns_query_t *query;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
query = asyncns_getaddrinfo(server_ctx->asyncns,
host, port, &hints);
if (query == NULL) {
ERROR("[udp] asyncns_getaddrinfo");
goto CLEAN_UP;
}
struct query_ctx *query_ctx = new_query_ctx(query,
buf + addr_header_len,
buf_len - addr_header_len);
query_ctx->server_ctx = server_ctx;
query_ctx->addr_header_len = addr_header_len;
query_ctx->src_addr = src_addr;
memcpy(query_ctx->addr_header, addr_header, addr_header_len);
asyncns_setuserdata(server_ctx->asyncns, query, query_ctx);
} else {
size_t addr_len = sizeof(struct sockaddr_in);
if (remote_ctx->dst_addr.ss_family == AF_INET6) {
addr_len = sizeof(struct sockaddr_in6);
}
int s = sendto(remote_ctx->fd, buf + addr_header_len,
buf_len - addr_header_len, 0,
(struct sockaddr *)&remote_ctx->dst_addr, addr_len);
if (s == -1) {
ERROR("[udp] sendto_remote");
}
}
#endif
CLEAN_UP:
free(buf);
}
static void remote_recv_cb(EV_P_ ev_io *w, int revents)
{
struct remote_ctx *remote_ctx = (struct remote_ctx *)w;
struct server_ctx *server_ctx = remote_ctx->server_ctx;
// server has been closed
if (server_ctx == NULL) {
LOGE("[udp] invalid server.");
close_and_free_remote(EV_A_ remote_ctx);
return;
}
if (verbose) {
LOGD("[udp] remote receive a packet");
}
// triger the timer
ev_timer_again(EV_A_ & remote_ctx->watcher);
struct sockaddr src_addr;
socklen_t src_addr_len = sizeof(src_addr);
char *buf = malloc(BUF_SIZE);
// recv
ssize_t buf_len = recvfrom(remote_ctx->fd, buf, BUF_SIZE, 0, &src_addr,
&src_addr_len);
if (buf_len == -1) {
// error on recv
// simply drop that packet
if (verbose) {
ERROR("[udp] server_recvfrom");
}
goto CLEAN_UP;
}
#ifdef UDPRELAY_LOCAL
buf = ss_decrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method);
if (buf == NULL) {
if (verbose) {
ERROR("[udp] server_ss_decrypt_all");
}
goto CLEAN_UP;
}
int len = parse_udprealy_header(buf, buf_len, NULL, NULL);
if (len == 0) {
LOGD("[udp] error in parse header");
// error in parse header
goto CLEAN_UP;
}
// server may return using a different address type other than the type we
// have used during sending
#ifdef UDPRELAY_TUNNEL
// Construct packet
buf_len -= len;
memmove(buf, buf + len, buf_len);
#else
// Construct packet
char *tmpbuf = malloc(buf_len + 3);
memset(tmpbuf, 0, 3);
memcpy(tmpbuf + 3, buf, buf_len);
free(buf);
buf = tmpbuf;
buf_len += 3;
#endif
#endif
#ifdef UDPRELAY_REMOTE
unsigned int addr_header_len = remote_ctx->addr_header_len;
// Construct packet
char *tmpbuf = malloc(buf_len + addr_header_len);
memcpy(tmpbuf, remote_ctx->addr_header, addr_header_len);
memcpy(tmpbuf + addr_header_len, buf, buf_len);
free(buf);
buf = tmpbuf;
buf_len += addr_header_len;
buf = ss_encrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method);
#endif
size_t addr_len = sizeof(struct sockaddr_in);
if (remote_ctx->src_addr.ss_family == AF_INET6) {
addr_len = sizeof(struct sockaddr_in6);
}
int s = sendto(server_ctx->fd, buf, buf_len, 0,
(struct sockaddr *)&remote_ctx->src_addr, addr_len);
if (s == -1) {
ERROR("[udp] sendto_local");
}
CLEAN_UP:
free(buf);
}