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socks5_proxy_server.c
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socks5_proxy_server.c
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/*
* socks5 proxy server
*
* @build: make examples
*
* @proxy_server bin/socks5_proxy_server 1080
* bin/socks5_proxy_server 1080 username password
*
* @proxy_client curl -v http://www.example.com/ --proxy socks5://127.0.0.1:1080
* curl -v http://www.example.com/ --proxy socks5://username:[email protected]:1080
*
*/
#include "hv.h"
#include "hloop.h"
static char proxy_host[64] = "0.0.0.0";
static int proxy_port = 1080;
static const char* auth_username = NULL;
static const char* auth_password = NULL;
#define SOCKS5_VERSION ((uint8_t)5)
#define SOCKS5_AUTH_VERSION ((uint8_t)1)
#define SOCKS5_AUTH_SUCCESS ((uint8_t)0)
#define SOCKS5_AUTH_FAILURE ((uint8_t)1)
typedef enum {
NoAuth = 0,
GssApiAuth = 1,
UserPassAuth = 2,
} socks5_auth_method;
typedef enum {
ConnectCommand = 1,
BindCommand = 2,
AssociateCommand= 3,
} socks5_command;
typedef enum {
IPv4Addr = 1,
FqdnAddr = 3,
IPv6Addr = 4,
} socks5_addr_type;
typedef enum {
SuccessReply = 0,
ServerFailure = 1,
RuleFailure = 2,
NetworkUnreachable = 3,
HostUnreachable = 4,
ConnectRefused = 5,
TtlExpired = 6,
CommandNotSupported = 7,
AddrTypeNotSupported= 8,
} socks5_reply_code;
typedef enum {
s_begin,
s_auth_methods_count,
s_auth_methods,
s_auth_username_len,
s_auth_username,
s_auth_password_len,
s_auth_password,
s_request,
s_dst_addr_type,
s_dst_addr_len,
s_dst_addr,
s_dst_port,
s_upstream,
s_end,
} socks5_state_e;
typedef struct {
hio_t* io;
socks5_state_e state;
socks5_addr_type addr_type;
sockaddr_u addr;
} socks5_conn_t;
/*
* workflow:
* hloop_new -> hloop_create_tcp_server -> hloop_run
* on_accept -> HV_ALLOC(socks5_conn_t) -> hio_readbytes(s_auth_methods_count:2) ->
* on_recv -> hio_readbytes(s_auth_methods) ->
* on_recv -> hio_write(auth_method) -> hio_readbytes(s_auth_username_len:2) ->
* on_recv -> hio_readbytes(s_auth_username) ->
* on_recv -> hio_readbytes(s_auth_password_len:1) ->
* on_recv -> hio_readbytes(s_auth_password) -> hio_write(auth_result) ->
* on_recv -> hio_readbytes(s_request:3) ->
* on_recv -> hio_readbytes(addr_type:1) ->
* on_recv -> hio_readbytes(addr_len:1) ->
* on_recv -> hio_readbytes(addr) ->
* on_recv -> hio_readbytes(port:2) ->
* on_recv -> hio_setup_tcp_upstream(io, addr, port) ->
* on_close -> hio_close_upstream -> HV_FREE(socks5_conn_t)
*
*/
static void on_upstream_connect(hio_t* upstream_io) {
// printf("on_upstream_connect connfd=%d\n", hio_fd(upstream_io));
socks5_conn_t* conn = (socks5_conn_t*)hevent_userdata(upstream_io);
sockaddr_u* localaddr = (sockaddr_u*)hio_localaddr(upstream_io);
uint8_t resp[32] = { SOCKS5_VERSION, SuccessReply, 0, IPv4Addr, 127,0,0,1, 0,80, 0 };
int resp_len = 3;
if (localaddr->sa.sa_family == AF_INET) {
resp[resp_len++] = IPv4Addr;
memcpy(resp + resp_len, &localaddr->sin.sin_addr, 4); resp_len += 4;
memcpy(resp + resp_len, &localaddr->sin.sin_port, 2); resp_len += 2;
} else if (localaddr->sa.sa_family == AF_INET6) {
resp[resp_len++] = IPv6Addr;
memcpy(resp + resp_len, &localaddr->sin6.sin6_addr, 16); resp_len += 16;
memcpy(resp + resp_len, &localaddr->sin6.sin6_port, 2); resp_len += 2;
}
hio_write(conn->io, resp, resp_len);
hio_setcb_read(upstream_io, hio_write_upstream);
hio_setcb_read(conn->io, hio_write_upstream);
hio_read(conn->io);
hio_read(upstream_io);
}
static void on_close(hio_t* io) {
// printf("on_close fd=%d error=%d\n", hio_fd(io), hio_error(io));
socks5_conn_t* conn = (socks5_conn_t*)hevent_userdata(io);
if (conn) {
hevent_set_userdata(io, NULL);
HV_FREE(conn);
}
hio_close_upstream(io);
}
static void on_recv(hio_t* io, void* buf, int readbytes) {
socks5_conn_t* conn = (socks5_conn_t*)hevent_userdata(io);
const uint8_t* bytes = (uint8_t*)buf;
switch(conn->state) {
case s_begin:
// printf("s_begin\n");
conn->state = s_auth_methods_count;
case s_auth_methods_count:
// printf("s_auth_methods_count\n");
{
assert(readbytes == 2);
uint8_t version = bytes[0];
uint8_t methods_count = bytes[1];
if (version != SOCKS5_VERSION || methods_count == 0) {
fprintf(stderr, "Unsupprted socks version: %d\n", (int)version);
hio_close(io);
return;
}
conn->state = s_auth_methods;
hio_readbytes(io, methods_count);
}
break;
case s_auth_methods:
// printf("s_auth_methods\n");
{
// TODO: check auth methos
uint8_t auth_method = NoAuth;
if (auth_username && auth_password) {
auth_method = UserPassAuth;
} else {
// TODO: Implement more auth methods
}
// send auth mothod
uint8_t resp[2] = { SOCKS5_VERSION, NoAuth };
resp[1] = auth_method;
hio_write(io, resp, 2);
if (auth_method == NoAuth) {
conn->state = s_request;
hio_readbytes(io, 3);
} else if (auth_method == UserPassAuth) {
conn->state = s_auth_username_len;
hio_readbytes(io, 2);
}
}
break;
case s_auth_username_len:
// printf("s_auth_username_len\n");
{
assert(readbytes == 2);
uint8_t auth_version = bytes[0];
uint8_t username_len = bytes[1];
if (auth_version != SOCKS5_AUTH_VERSION || username_len == 0) {
fprintf(stderr, "Unsupported auth version: %d\n", (int)auth_version);
hio_close(io);
return;
}
conn->state = s_auth_username;
hio_readbytes(io, username_len);
}
break;
case s_auth_username:
// printf("s_auth_username\n");
{
char* username = (char*)bytes;
printf("username=%.*s\n", readbytes, username);
if (readbytes != strlen(auth_username) ||
strncmp(username, auth_username, readbytes) != 0) {
fprintf(stderr, "User authentication failed!\n");
uint8_t resp[2] = { SOCKS5_AUTH_VERSION, SOCKS5_AUTH_FAILURE };
hio_write(io, resp, 2);
hio_close(io);
return;
}
conn->state = s_auth_password_len;
hio_readbytes(io, 1);
}
break;
case s_auth_password_len:
// printf("s_auth_password_len\n");
{
assert(readbytes == 1);
uint8_t password_len = bytes[0];
if (password_len == 0) {
fprintf(stderr, "Miss password\n");
uint8_t resp[2] = { SOCKS5_AUTH_VERSION, SOCKS5_AUTH_FAILURE };
hio_write(io, resp, 2);
hio_close(io);
return;
}
conn->state = s_auth_password;
hio_readbytes(io, password_len);
}
break;
case s_auth_password:
// printf("s_auth_password\n");
{
char* password = (char*)bytes;
printf("password=%.*s\n", readbytes, password);
uint8_t resp[2] = { SOCKS5_AUTH_VERSION, SOCKS5_AUTH_SUCCESS };
if (readbytes != strlen(auth_password) ||
strncmp(password, auth_password, readbytes) != 0) {
fprintf(stderr, "User authentication failed!\n");
resp[1] = SOCKS5_AUTH_FAILURE;
hio_write(io, resp, 2);
hio_close(io);
return;
}
hio_write(io, resp, 2);
conn->state = s_request;
hio_readbytes(io, 3);
}
break;
case s_request:
// printf("s_request\n");
{
assert(readbytes == 3);
uint8_t version = bytes[0];
uint8_t cmd = bytes[1];
if (version != SOCKS5_VERSION || cmd != ConnectCommand) {
// TODO: Implement other commands
fprintf(stderr, "Unsupported command: %d\n", (int)cmd);
hio_close(io);
return;
}
conn->state = s_dst_addr_type;
hio_readbytes(io, 1);
}
break;
case s_dst_addr_type:
// printf("s_dst_addr_type\n");
{
assert(readbytes == 1);
conn->addr_type = (socks5_addr_type)bytes[0];
if (conn->addr_type == IPv4Addr) {
conn->state = s_dst_addr;
hio_readbytes(io, 4);
} else if (conn->addr_type == FqdnAddr) {
conn->state = s_dst_addr_len;
hio_readbytes(io, 1);
} else if (conn->addr_type == IPv6Addr) {
conn->state = s_dst_addr;
hio_readbytes(io, 16);
} else {
fprintf(stderr, "Unsupported addr type: %d\n", (int)conn->addr_type);
hio_close(io);
return;
}
}
break;
case s_dst_addr_len:
// printf("s_dst_addr_len\n");
{
uint8_t addr_len = bytes[0];
if (addr_len == 0) {
fprintf(stderr, "Miss domain!\n");
hio_close(io);
return;
}
conn->state = s_dst_addr;
hio_readbytes(io, addr_len);
}
break;
case s_dst_addr:
// printf("s_dst_addr\n");
{
if (conn->addr_type == IPv4Addr) {
assert(readbytes == 4);
conn->addr.sa.sa_family = AF_INET;
memcpy(&conn->addr.sin.sin_addr, bytes, 4);
} else if (conn->addr_type == IPv6Addr) {
assert(readbytes == 16);
conn->addr.sa.sa_family = AF_INET6;
memcpy(&conn->addr.sin6.sin6_addr, bytes, 16);
} else {
char* host = NULL;
STACK_OR_HEAP_ALLOC(host, readbytes + 1, 256);
memcpy(host, bytes, readbytes);
host[readbytes] = '\0';
// TODO: async DNS
int ret = ResolveAddr(host, &conn->addr);
STACK_OR_HEAP_FREE(host);
if (ret != 0) {
fprintf(stderr, "Resolve %.*s failed!\n", readbytes, (char*)bytes);
hio_close(io);
return;
}
}
conn->state = s_dst_port;
hio_readbytes(io, 2);
}
break;
case s_dst_port:
// printf("s_dst_port\n");
{
assert(readbytes == 2);
uint16_t port = ((uint16_t)bytes[0]) << 8 | bytes[1];
// printf("port=%d\n", port);
sockaddr_set_port(&conn->addr, port);
hloop_t* loop = hevent_loop(io);
// hio_t* upstream_io = hio_setup_tcp_upstream(io, conn->host, conn->port, 0);
// hio_t* upstream_io = hio_create_socket(loop, conn->host, conn->port, HIO_TYPE_TCP, HIO_CLIENT_SIDE);
int sockfd = socket(conn->addr.sa.sa_family, SOCK_STREAM, 0);
if (sockfd < 0) {
perror("socket");
hio_close(io);
return;
}
hio_t* upstream_io = hio_get(loop, sockfd);
assert(upstream_io != NULL);
hio_set_peeraddr(upstream_io, &conn->addr.sa, sockaddr_len(&conn->addr));
hevent_set_userdata(upstream_io, conn);
// io <=> upstream_io
hio_setup_upstream(io, upstream_io);
hio_setcb_connect(upstream_io, on_upstream_connect);
hio_setcb_close(upstream_io, hio_close_upstream);
conn->state = s_upstream;
// printf("connect to ");
// SOCKADDR_PRINT(hio_peeraddr(upstream_io));
hio_connect(upstream_io);
}
break;
case s_upstream:
hio_write_upstream(io, buf, readbytes);
break;
case s_end:
break;
default:
break;
}
}
static void on_accept(hio_t* io) {
/*
printf("on_accept connfd=%d\n", hio_fd(io));
char localaddrstr[SOCKADDR_STRLEN] = {0};
char peeraddrstr[SOCKADDR_STRLEN] = {0};
printf("accept connfd=%d [%s] <= [%s]\n", hio_fd(io),
SOCKADDR_STR(hio_localaddr(io), localaddrstr),
SOCKADDR_STR(hio_peeraddr(io), peeraddrstr));
*/
hio_setcb_read(io, on_recv);
hio_setcb_close(io, on_close);
socks5_conn_t* conn = NULL;
HV_ALLOC_SIZEOF(conn);
conn->io = io;
hevent_set_userdata(io, conn);
// start read
conn->state = s_auth_methods_count;
hio_readbytes(io, 2);
}
int main(int argc, char** argv) {
if (argc < 2) {
printf("Usage: %s proxy_port [username] [password]\n", argv[0]);
return -10;
}
proxy_port = atoi(argv[1]);
if (argc > 3) {
auth_username = argv[2];
auth_password = argv[3];
}
hloop_t* loop = hloop_new(0);
hio_t* listenio = hloop_create_tcp_server(loop, proxy_host, proxy_port, on_accept);
if (listenio == NULL) {
return -20;
}
printf("socks5 proxy server listening on %s:%d, listenfd=%d\n", proxy_host, proxy_port, hio_fd(listenio));
hloop_run(loop);
hloop_free(&loop);
return 0;
}