struct remote *connect_to_remote(struct addrinfo *res, const char *iface)
{
int sockfd;
int opt = 1;
// initilize remote socks
sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (sockfd < 0)
{
ERROR("socket");
close(sockfd);
return NULL;
}
setsockopt(sockfd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt));
#ifdef SO_NOSIGPIPE
setsockopt(sockfd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
#endif
struct remote *remote = new_remote(sockfd);
// setup remote socks
setnonblocking(sockfd);
#ifdef SET_INTERFACE
if (iface) setinterface(sockfd, iface);
#endif
connect(sockfd, res->ai_addr, res->ai_addrlen);
return remote;
}
static void accept_cb(EV_P_ ev_io *w, int revents)
{
struct listen_ctx *listener = (struct listen_ctx *)w;
int serverfd = accept(listener->fd, NULL, NULL);
if (serverfd == -1) {
ERROR("accept");
return;
}
setnonblocking(serverfd);
int opt = 1;
setsockopt(serverfd, SOL_TCP, TCP_NODELAY, &opt, sizeof(opt));
#ifdef SO_NOSIGPIPE
setsockopt(serverfd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
#endif
int index = rand() % listener->remote_num;
struct sockaddr *remote_addr = listener->remote_addr[index];
int remotefd = socket(remote_addr->sa_family, SOCK_STREAM, IPPROTO_TCP);
if (remotefd < 0) {
ERROR("socket");
return;
}
#ifdef ANDROID
if (vpn) {
if (protect_socket(remotefd) == -1) {
ERROR("protect_socket");
close(remotefd);
return;
}
}
#endif
setsockopt(remotefd, SOL_TCP, TCP_NODELAY, &opt, sizeof(opt));
#ifdef SO_NOSIGPIPE
setsockopt(remotefd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
#endif
// Setup
setnonblocking(remotefd);
#ifdef SET_INTERFACE
if (listener->iface) {
setinterface(remotefd, listener->iface);
}
#endif
struct server *server = new_server(serverfd, listener->method);
struct remote *remote = new_remote(remotefd, listener->timeout);
server->destaddr = listener->tunnel_addr;
server->remote = remote;
remote->server = server;
connect(remotefd, remote_addr, get_sockaddr_len(remote_addr));
// listen to remote connected event
ev_io_start(EV_A_ & remote->send_ctx->io);
ev_timer_start(EV_A_ & remote->send_ctx->watcher);
}
static void accept_cb (EV_P_ ev_io *w, int revents)
{
struct listen_ctx *listener = (struct listen_ctx *)w;
int serverfd = accept(listener->fd, NULL, NULL);
if (serverfd == -1)
{
ERROR("accept");
return;
}
setnonblocking(serverfd);
int opt = 1;
setsockopt(serverfd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt));
#ifdef SO_NOSIGPIPE
setsockopt(serverfd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
#endif
struct addrinfo hints, *res;
int sockfd;
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
int index = rand() % listener->remote_num;
int err = getaddrinfo(listener->remote_host[index], listener->remote_port, &hints, &res);
if (err)
{
ERROR("getaddrinfo");
return;
}
sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (sockfd < 0)
{
ERROR("socket");
close(sockfd);
freeaddrinfo(res);
return;
}
setsockopt(sockfd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt));
#ifdef SO_NOSIGPIPE
setsockopt(sockfd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
#endif
// Setup
setnonblocking(sockfd);
#ifdef SET_INTERFACE
if (listener->iface) setinterface(sockfd, listener->iface);
#endif
struct server *server = new_server(serverfd, listener->method);
struct remote *remote = new_remote(sockfd, listener->timeout);
server->remote = remote;
remote->server = server;
connect(sockfd, res->ai_addr, res->ai_addrlen);
freeaddrinfo(res);
// listen to remote connected event
ev_io_start(EV_A_ &remote->send_ctx->io);
ev_timer_start(EV_A_ &remote->send_ctx->watcher);
}
struct remote *connect_to_remote(struct addrinfo *res, struct server *server)
{
int sockfd;
int opt = 1;
const char *iface = server->listen_ctx->iface;
// initilize remote socks
sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (sockfd < 0)
{
ERROR("socket");
close(sockfd);
return NULL;
}
setsockopt(sockfd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt));
#ifdef SO_NOSIGPIPE
setsockopt(sockfd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
#endif
struct remote *remote = new_remote(sockfd);
// setup remote socks
setnonblocking(sockfd);
#ifdef SET_INTERFACE
if (iface) setinterface(sockfd, iface);
#endif
#ifdef TCP_FASTOPEN
if (fast_open) {
ssize_t s = sendto(sockfd, server->buf + server->buf_idx, server->buf_len, MSG_FASTOPEN, res->ai_addr, res->ai_addrlen);
if (s == -1) {
if (errno == EAGAIN || errno == EWOULDBLOCK) {
// The remote server doesn't support tfo or it's the first connection to the server.
// It will automatically fall back to conventional TCP.
}
else if (errno == EOPNOTSUPP || errno == EPROTONOSUPPORT || errno == ENOPROTOOPT) {
LOGE("fast open is not supported on this platform");
connect(sockfd, res->ai_addr, res->ai_addrlen);
}
else {
ERROR("sendto");
}
}
else if (s < server->buf_len) {
server->buf_idx += s;
server->buf_len -= s;
}
else {
server->buf_idx = 0;
server->buf_len = 0;
}
} else
#endif
connect(sockfd, res->ai_addr, res->ai_addrlen);
return remote;
}
static struct remote * connect_to_remote(struct listen_ctx *listener,
const char *host, const char *port)
{
int sockfd;
struct addrinfo *remote_res;
struct addrinfo hints;
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
int index = rand() % listener->remote_num;
int err;
if (host == NULL || port == NULL) {
if (verbose) {
LOGD("connect to server: %s:%s", listener->remote_addr[index].host,
listener->remote_addr[index].port);
}
err = getaddrinfo(listener->remote_addr[index].host,
listener->remote_addr[index].port, &hints,
&remote_res);
} else {
err = getaddrinfo(host, port, &hints, &remote_res);
}
if (err) {
ERROR("getaddrinfo");
return NULL;
}
sockfd = socket(remote_res->ai_family, remote_res->ai_socktype,
remote_res->ai_protocol);
if (sockfd < 0) {
ERROR("socket");
freeaddrinfo(remote_res);
return NULL;
}
#ifdef SO_NOSIGPIPE
int opt = 1;
setsockopt(sockfd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
#endif
// Setup
setnonblocking(sockfd);
#ifdef SET_INTERFACE
if (listener->iface) {
setinterface(sockfd, listener->iface);
}
#endif
struct remote *remote = new_remote(sockfd, listener->timeout);
remote->addr_info = remote_res;
return remote;
}
static remote_t *create_remote(listen_ctx_t *listener,
struct sockaddr *addr)
{
struct sockaddr *remote_addr;
int index = rand() % listener->remote_num;
if (addr == NULL) {
remote_addr = listener->remote_addr[index];
} else {
remote_addr = addr;
}
int remotefd = socket(remote_addr->sa_family, SOCK_STREAM, IPPROTO_TCP);
if (remotefd < 0) {
ERROR("socket");
return NULL;
}
int opt = 1;
setsockopt(remotefd, SOL_TCP, TCP_NODELAY, &opt, sizeof(opt));
#ifdef SO_NOSIGPIPE
setsockopt(remotefd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
#endif
// Setup
setnonblocking(remotefd);
#ifdef SET_INTERFACE
if (listener->iface) {
setinterface(remotefd, listener->iface);
}
#endif
remote_t *remote = new_remote(remotefd, listener->timeout);
remote->addr_len = get_sockaddr_len(remote_addr);
memcpy(&(remote->addr), remote_addr, remote->addr_len);
remote->remote_index = index;
return remote;
}
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;
memset(&msg, 0, sizeof(struct msghdr));
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->data;
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) {
if (verbose) {
LOGI("[udp] UDP server_recv_recvmsg fragmentation");
}
}
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->data, 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) {
if (verbose) {
LOGI("[udp] server_recv_recvfrom fragmentation");
}
}
buf->len = r;
#endif
if (verbose) {
LOGI("[udp] server receive a packet");
}
#ifdef MODULE_REMOTE
tx += buf->len;
int err = server_ctx->crypto->decrypt_all(buf, server_ctx->crypto->cipher, buf_size);
if (err) {
// drop the packet silently
goto CLEAN_UP;
}
#endif
#ifdef MODULE_LOCAL
#if !defined(MODULE_TUNNEL) && !defined(MODULE_REDIR)
#ifdef __ANDROID__
tx += buf->len;
#endif
uint8_t frag = *(uint8_t *)(buf->data + 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 MODULE_REDIR
char addr_header[512] = { 0 };
int addr_header_len = construct_udprelay_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->data + addr_header_len, buf->data, buf->len);
memcpy(buf->data, 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;
memset(&host_addr, 0, sizeof(struct in_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;
memset(&host_addr, 0, sizeof(struct in6_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->data + addr_header_len, buf->data, buf->len);
memcpy(buf->data, 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_udprelay_header(buf->data + offset, buf->len - offset,
host, port, &dst_addr);
if (addr_header_len == 0) {
// error in parse header
goto CLEAN_UP;
}
char *addr_header = buf->data + 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->data, buf->data + offset, buf->len);
}
int err = server_ctx->crypto->encrypt_all(buf, server_ctx->crypto->cipher, buf_size);
if (err) {
// drop the packet silently
goto CLEAN_UP;
}
if (buf->len > packet_size) {
if (verbose) {
LOGI("[udp] server_recv_sendto fragmentation");
}
}
int s = sendto(remote_ctx->fd, buf->data, 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) {
if (verbose) {
LOGI("[udp] server_recv_sendto fragmentation");
}
}
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->data + 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(struct addrinfo));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_protocol = IPPROTO_UDP;
struct query_ctx *query_ctx = new_query_ctx(buf->data + 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
query_resolve_cb(struct sockaddr *addr, void *data)
{
struct query_ctx *query_ctx = (struct query_ctx *)data;
struct ev_loop *loop = query_ctx->server_ctx->loop;
if (verbose) {
LOGI("[udp] udns resolved");
}
query_ctx->query = NULL;
if (addr == NULL) {
LOGE("[udp] udns returned an error");
} else {
remote_ctx_t *remote_ctx = query_ctx->remote_ctx;
int cache_hit = 0;
// Lookup in the conn cache
if (remote_ctx == NULL) {
char *key = hash_key(AF_UNSPEC, &query_ctx->src_addr);
cache_lookup(query_ctx->server_ctx->conn_cache, key, HASH_KEY_LEN, (void *)&remote_ctx);
}
if (remote_ctx == NULL) {
int remotefd = create_remote_socket(addr->sa_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 (query_ctx->server_ctx->iface) {
if (setinterface(remotefd, query_ctx->server_ctx->iface) == -1)
ERROR("setinterface");
}
#endif
remote_ctx = new_remote(remotefd, query_ctx->server_ctx);
remote_ctx->src_addr = query_ctx->src_addr;
remote_ctx->server_ctx = query_ctx->server_ctx;
remote_ctx->addr_header_len = query_ctx->addr_header_len;
memcpy(remote_ctx->addr_header, query_ctx->addr_header,
query_ctx->addr_header_len);
} else {
ERROR("[udp] bind() error");
}
} else {
cache_hit = 1;
}
if (remote_ctx != NULL) {
memcpy(&remote_ctx->dst_addr, addr, sizeof(struct sockaddr_storage));
size_t addr_len = get_sockaddr_len(addr);
int s = sendto(remote_ctx->fd, query_ctx->buf->data, query_ctx->buf->len,
0, 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
char *key = hash_key(AF_UNSPEC, &remote_ctx->src_addr);
cache_insert(query_ctx->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);
}
}
}
}
// clean up
close_and_free_query(EV_A_ query_ctx);
}
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 query_resolve_cb(EV_P_ ev_timer *watcher, int revents)
{
int err;
struct addrinfo *result, *rp;
struct query_ctx *query_ctx = (struct query_ctx *)((void*)watcher);
asyncns_t *asyncns = query_ctx->server_ctx->asyncns;
asyncns_query_t *query = query_ctx->query;
if (asyncns == NULL || query == NULL)
{
LOGE("invalid dns query.");
close_and_free_query(EV_A_ query_ctx);
return;
}
if (asyncns_wait(asyncns, 0) == -1)
{
// asyncns error
FATAL("asyncns exit unexpectedly.");
}
if (!asyncns_isdone(asyncns, query))
{
// wait reolver
return;
}
if (verbose)
{
LOGD("[udp] asyncns resolved.");
}
ev_timer_stop(EV_A_ watcher);
err = asyncns_getaddrinfo_done(asyncns, query, &result);
if (err)
{
ERROR("getaddrinfo");
}
else
{
// Use IPV4 address if possible
for (rp = result; rp != NULL; rp = rp->ai_next)
{
if (rp->ai_family == AF_INET) break;
}
if (rp == NULL)
{
rp = result;
}
int remotefd = create_remote_socket(rp->ai_family == AF_INET6);
if (remotefd != -1)
{
setnonblocking(remotefd);
#ifdef SO_NOSIGPIPE
int opt = 1;
setsockopt(remotefd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
#endif
#ifdef SET_INTERFACE
if (query_ctx->server_ctx->iface)
setinterface(remotefd, query_ctx->server_ctx->iface);
#endif
struct remote_ctx *remote_ctx = new_remote(remotefd, query_ctx->server_ctx);
remote_ctx->src_addr = query_ctx->src_addr;
remote_ctx->dst_addr = *rp->ai_addr;
remote_ctx->server_ctx = query_ctx->server_ctx;
remote_ctx->addr_header_len = query_ctx->addr_header_len;
memcpy(remote_ctx->addr_header, query_ctx->addr_header, query_ctx->addr_header_len);
// Add to conn cache
char *key = hash_key(remote_ctx->addr_header,
remote_ctx->addr_header_len, &remote_ctx->src_addr);
cache_insert(query_ctx->server_ctx->conn_cache, key, (void *)remote_ctx);
ev_io_start(EV_A_ &remote_ctx->io);
int s = sendto(remote_ctx->fd, query_ctx->buf, query_ctx->buf_len, 0, &remote_ctx->dst_addr, sizeof(remote_ctx->dst_addr));
if (s == -1)
{
ERROR("udprelay_sendto_remote");
close_and_free_remote(EV_A_ remote_ctx);
}
}
else
{
ERROR("udprelay bind() error..");
}
}
// clean up
asyncns_freeaddrinfo(result);
close_and_free_query(EV_A_ query_ctx);
}
static void
accept_cb(EV_P_ ev_io *w, int revents)
{
struct listen_ctx *listener = (struct listen_ctx *)w;
int serverfd = accept(listener->fd, NULL, NULL);
if (serverfd == -1) {
ERROR("accept");
return;
}
setnonblocking(serverfd);
int opt = 1;
setsockopt(serverfd, SOL_TCP, TCP_NODELAY, &opt, sizeof(opt));
#ifdef SO_NOSIGPIPE
setsockopt(serverfd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
#endif
int index = rand() % listener->remote_num;
struct sockaddr *remote_addr = listener->remote_addr[index];
int remotefd = socket(remote_addr->sa_family, SOCK_STREAM, IPPROTO_TCP);
if (remotefd == -1) {
ERROR("socket");
return;
}
#ifdef ANDROID
if (vpn) {
int not_protect = 0;
if (remote_addr->sa_family == AF_INET) {
struct sockaddr_in *s = (struct sockaddr_in *)remote_addr;
if (s->sin_addr.s_addr == inet_addr("127.0.0.1"))
not_protect = 1;
}
if (!not_protect) {
if (protect_socket(remotefd) == -1) {
ERROR("protect_socket");
close(remotefd);
return;
}
}
}
#endif
setsockopt(remotefd, SOL_TCP, TCP_NODELAY, &opt, sizeof(opt));
#ifdef SO_NOSIGPIPE
setsockopt(remotefd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
#endif
if (listener->mptcp == 1) {
int err = setsockopt(remotefd, SOL_TCP, MPTCP_ENABLED, &opt, sizeof(opt));
if (err == -1) {
ERROR("failed to enable multipath TCP");
}
}
// Setup
setnonblocking(remotefd);
#ifdef SET_INTERFACE
if (listener->iface) {
if (setinterface(remotefd, listener->iface) == -1)
ERROR("setinterface");
}
#endif
server_t *server = new_server(serverfd, listener->method);
remote_t *remote = new_remote(remotefd, listener->timeout);
server->destaddr = listener->tunnel_addr;
server->remote = remote;
remote->server = server;
int r = connect(remotefd, remote_addr, get_sockaddr_len(remote_addr));
if (r == -1 && errno != CONNECT_IN_PROGRESS) {
ERROR("connect");
close_and_free_remote(EV_A_ remote);
close_and_free_server(EV_A_ server);
return;
}
// listen to remote connected event
ev_io_start(EV_A_ & remote->send_ctx->io);
ev_timer_start(EV_A_ & remote->send_ctx->watcher);
}
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;
memset(&src_addr, 0, sizeof(struct sockaddr_storage));
char *buf = malloc(BUF_SIZE);
socklen_t src_addr_len = sizeof(struct sockaddr_storage);
unsigned int offset = 0;
#ifdef UDPRELAY_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;
iov[0].iov_len = BUF_SIZE;
msg.msg_iov = iov;
msg.msg_iovlen = 1;
ssize_t buf_len = recvmsg(server_ctx->fd, &msg, 0);
if (buf_len == -1) {
ERROR("[udp] server_recvmsg");
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 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
ERROR("[udp] server_recvfrom");
goto CLEAN_UP;
}
#endif
if (verbose) {
LOGI("[udp] server receive a packet");
}
#ifdef UDPRELAY_REMOTE
tx += buf_len;
buf = ss_decrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method, server_ctx->auth);
if (buf == NULL) {
ERROR("[udp] server_ss_decrypt_all");
goto CLEAN_UP;
}
#endif
#ifdef UDPRELAY_LOCAL
#if !defined(UDPRELAY_TUNNEL) && !defined(UDPRELAY_REDIR)
uint8_t frag = *(uint8_t *)(buf + 2);
offset += 3;
#endif
#endif
// packet size > default MTU
if (verbose && buf_len > MTU) {
LOGE("[udp] possible ip fragment, size: %d", (int)buf_len);
}
/*
*
* 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 UDPRELAY_REDIR
char addr_header[256] = { 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
if (BUF_SIZE < buf_len + addr_header_len) {
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;
char *key = hash_key(dst_addr.ss_family, &src_addr);
#elif UDPRELAY_TUNNEL
char addr_header[256] = { 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
if (BUF_SIZE < buf_len + addr_header_len) {
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;
char *key = hash_key(ip.version == 4 ? AF_INET : AF_INET6, &src_addr);
#else
char host[256] = { 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 + 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 + offset;
char *key = hash_key(dst_addr.ss_family, &src_addr);
#endif
struct cache *conn_cache = server_ctx->conn_cache;
struct remote_ctx *remote_ctx = NULL;
cache_lookup(conn_cache, key, HASH_KEY_LEN, (void *)&remote_ctx);
if (remote_ctx != NULL) {
if (memcmp(&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 UDPRELAY_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 UDPRELAY_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 UDPRELAY_LOCAL
#if !defined(UDPRELAY_TUNNEL) && !defined(UDPRELAY_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 SET_INTERFACE
if (server_ctx->iface) {
setinterface(remotefd, server_ctx->iface);
}
#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, buf + offset, buf_len);
}
if (server_ctx->auth) {
buf[0] |= ONETIMEAUTH_FLAG;
}
buf = ss_encrypt_all(BUF_SIZE, buf, &buf_len, server_ctx->method, server_ctx->auth);
int s = sendto(remote_ctx->fd, buf, buf_len, 0, remote_addr, remote_addr_len);
if (s == -1) {
ERROR("[udp] sendto_remote");
}
#else
int cache_hit = 0;
int need_query = 0;
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 {
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 SET_INTERFACE
if (server_ctx->iface) {
setinterface(remotefd, server_ctx->iface);
}
#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);
} 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 + 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 + 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:
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 query_resolve_cb(EV_P_ ev_io *w, int revents)
{
int err;
struct addrinfo *result, *rp;
struct resolve_ctx *resolve_ctx = (struct resolve_ctx *)w;
asyncns_t *asyncns = resolve_ctx->asyncns;
err = asyncns_handle(asyncns);
if (err == ASYNCNS_HANDLE_AGAIN) {
// try again
return;
} else if (err == ASYNCNS_HANDLE_ERROR) {
// asyncns error
FATAL("[udp] asyncns exit unexpectedly.");
}
asyncns_query_t *query = asyncns_getnext(asyncns);
struct query_ctx *query_ctx = (struct query_ctx *)asyncns_getuserdata(
asyncns, query);
if (!asyncns_isdone(asyncns, query)) {
// wait reolver
return;
}
if (verbose) {
LOGD("[udp] asyncns resolved.");
}
query_ctx->query = NULL;
err = asyncns_getaddrinfo_done(asyncns, query, &result);
if (err) {
ERROR("[udp] asysncns_getaddrinfo");
} else {
// Use IPV4 address if possible
for (rp = result; rp != NULL; rp = rp->ai_next) {
if (rp->ai_family == AF_INET) {
break;
}
}
if (rp == NULL) {
rp = result;
}
int remotefd = create_remote_socket(rp->ai_family == AF_INET6);
if (remotefd != -1) {
setnonblocking(remotefd);
#ifdef SO_BROADCAST
set_broadcast(remotefd);
#endif
#ifdef SO_NOSIGPIPE
set_nosigpipe(remotefd);
#endif
#ifdef SET_INTERFACE
if (query_ctx->server_ctx->iface) {
setinterface(remotefd, query_ctx->server_ctx->iface);
}
#endif
struct remote_ctx *remote_ctx = new_remote(remotefd,
query_ctx->server_ctx);
remote_ctx->src_addr = query_ctx->src_addr;
remote_ctx->dst_addr = *((struct sockaddr_storage *)rp->ai_addr);
remote_ctx->server_ctx = query_ctx->server_ctx;
remote_ctx->addr_header_len = query_ctx->addr_header_len;
memcpy(remote_ctx->addr_header, query_ctx->addr_header,
query_ctx->addr_header_len);
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, query_ctx->buf, query_ctx->buf_len,
0, (struct sockaddr *)&remote_ctx->dst_addr,
addr_len);
if (s == -1) {
ERROR("[udp] sendto_remote");
close_and_free_remote(EV_A_ remote_ctx);
} else {
// Add to conn cache
char *key = hash_key(remote_ctx->addr_header,
remote_ctx->addr_header_len,
&remote_ctx->src_addr);
cache_insert(query_ctx->server_ctx->conn_cache, key,
(void *)remote_ctx);
ev_io_start(EV_A_ & remote_ctx->io);
}
} else {
ERROR("[udp] bind() error..");
}
}
// clean up
asyncns_freeaddrinfo(result);
close_and_free_query(EV_A_ query_ctx);
}