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// For rustc and libstd-rust version 1.48
use std::os::raw::{c_int, c_char};
use std::ffi::CStr;
use std::net::TcpStream;
use std::os::unix::io::{FromRawFd, IntoRawFd};
use std::io::Write;
use std::io::Read;
use std::io::ErrorKind;
use std::convert::TryFrom;
const REXMPP_SOCKS_BUF_LEN: usize = 300;
#[derive(PartialEq)]
#[repr(C)]
enum SocksIOState {
Writing,
Reading
}
#[derive(PartialEq)]
#[repr(C)]
enum SocksStage {
Auth,
Cmd,
Done
}
#[derive(PartialEq)]
#[repr(C)]
enum SocksErr {
Connected,
EAgain,
ETCP,
EReply,
EVersion,
ESocks,
EHost
}
#[repr(C)]
pub struct RexmppSocks {
fd: c_int,
host: *const c_char,
port: u16,
stage: SocksStage,
io_state: SocksIOState,
socks_error: c_int,
buf: [u8; REXMPP_SOCKS_BUF_LEN],
buf_len: usize,
buf_sent: usize
}
#[no_mangle]
extern "C" fn rexmpp_socks_proceed (s : &mut RexmppSocks) -> SocksErr {
if s.io_state == SocksIOState::Writing {
let mut stream : TcpStream = unsafe { TcpStream::from_raw_fd(s.fd) };
let ret = stream.write(&s.buf[s.buf_sent .. s.buf_len]);
// Make sure the connection is not closed by TcpStream.
TcpStream::into_raw_fd(stream);
match ret {
Ok(sent) => {
s.buf_sent += sent;
if s.buf_len == s.buf_sent {
s.buf_len = 0;
s.io_state = SocksIOState::Reading;
}
}
Err(error) => match error.kind() {
ErrorKind::WouldBlock => return SocksErr::EAgain,
_ => return SocksErr::ETCP
}
}
} else if s.io_state == SocksIOState::Reading {
let mut stream : TcpStream = unsafe { TcpStream::from_raw_fd(s.fd) };
let ret = stream.read(&mut s.buf[s.buf_len ..]);
// Make sure the connection is not closed by TcpStream.
TcpStream::into_raw_fd(stream);
match ret {
Ok(received) => {
s.buf_len += received;
if s.buf[0] != 5 {
return SocksErr::EVersion;
}
if s.buf_len >= 2 {
s.socks_error = s.buf[1].into();
}
if s.stage == SocksStage::Auth {
if s.buf_len > 2 {
return SocksErr::EReply;
}
if s.buf_len == 2 {
if s.socks_error != 0 {
return SocksErr::ESocks;
}
s.buf[0] = 5; // SOCKS version 5
s.buf[1] = 1; // Connect
s.buf[2] = 0; // Reserved
s.buf[3] = 3; // Domain name (todo: IP addresses)
let host_cstr : &CStr =
unsafe { CStr::from_ptr(s.host) };
let host_len = host_cstr.to_bytes().len();
match u8::try_from(host_len) {
Ok(u) => { s.buf[4] = u }
Err(_) => return SocksErr::EHost
}
s.buf[5 .. 5 + host_len].
copy_from_slice(&host_cstr.to_bytes());
s.buf[5 + host_len .. 7 + host_len].
copy_from_slice(&s.port.to_be_bytes());
s.buf_len = 7 + host_len;
s.buf_sent = 0;
s.stage = SocksStage::Cmd;
s.io_state = SocksIOState::Writing;
return rexmpp_socks_proceed(s);
}
} else if s.stage == SocksStage::Cmd {
if s.buf_len >= 5 {
let mut full_len : usize = 6;
match s.buf[3] {
// IPv4
1 => full_len += 4,
// Domain name
3 => full_len += usize::from(s.buf[4]) + 1,
// IPv6
4 => full_len += 16,
_ => return SocksErr::EReply
}
if s.buf_len > full_len {
return SocksErr::EReply;
}
if s.buf_len == full_len {
if s.socks_error != 0 {
return SocksErr::ESocks;
}
// We are done
s.stage = SocksStage::Done;
return SocksErr::Connected;
}
}
}
}
Err(error) => match error.kind() {
ErrorKind::WouldBlock => return SocksErr::EAgain,
_ => return SocksErr::ETCP
}
}
}
return SocksErr::EAgain
}
#[no_mangle]
extern "C" fn rexmpp_socks_init (
s : &mut RexmppSocks,
fd: c_int,
host: *const c_char,
port: u16
)
-> SocksErr
{
s.fd = fd;
s.host = host;
s.port = port;
s.socks_error = 0;
let host_cstr : &CStr = unsafe { CStr::from_ptr(host) };
if host_cstr.to_bytes().len() > 255 {
return SocksErr::EHost;
}
// Request authentication
s.stage = SocksStage::Auth;
s.io_state = SocksIOState::Writing;
s.buf[0] = 5; // SOCKS version 5
s.buf[1] = 1; // 1 supported method
s.buf[2] = 0; // No authentication required
s.buf_len = 3;
s.buf_sent = 0;
return rexmpp_socks_proceed(s);
}
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