Add Socks v5 support to daemon and wallet

(cherry picked from commit 23e29a5074f01cbb781f7e76b0c17ad2b6797af0)

1 files changed, 489 insertions, 26 deletions

diff --git a/src/net/socks.cpp b/src/net/socks.cpp
index 43d98024b..fc5be424e 100644
--- a/src/net/socks.cpp
+++ b/src/net/socks.cpp
@@ -31,6 +31,7 @@
 #include <algorithm>
 #include <boost/asio/bind_executor.hpp>
 #include <boost/asio/buffer.hpp>
+#include <boost/asio/coroutine.hpp>
 #include <boost/asio/dispatch.hpp>
 #include <boost/asio/read.hpp>
 #include <boost/asio/write.hpp>
@@ -38,8 +39,10 @@
 #include <boost/endian/conversion.hpp>
 #include <cstring>
 #include <limits>
+#include <numeric>
 #include <string>
 
+#include "net/parse.h"
 #include "net/net_utils_base.h"
 #include "net/tor_address.h"
 #include "net/i2p_address.h"
@@ -54,6 +57,16 @@ namespace socks
         constexpr const std::uint8_t v4tor_resolve_command = 0xf0;
         constexpr const std::uint8_t v4_request_granted = 90;
 
+        constexpr const std::uint8_t v5_noauth_method = 0;
+        constexpr const std::uint8_t v5_userpass_method = 2;
+        constexpr const std::uint8_t v5_connect_command = 1;
+        constexpr const std::uint8_t v5_reserved = 0;
+        constexpr const std::uint8_t v5_ipv4_type = 1;
+        constexpr const std::uint8_t v5_domain_type = 3;
+        constexpr const std::uint8_t v5_ipv6_type = 4;
+        constexpr const std::uint8_t v5_reply_success = 0;
+        constexpr const std::uint8_t v5_userpass_version = 1;
+
         struct v4_header
         {
             std::uint8_t version;
@@ -62,6 +75,114 @@ namespace socks
             boost::endian::big_uint32_t ip;
         };
 
+        struct v5_noauth_initial
+        {
+            std::uint8_t version;
+            std::uint8_t n_methods;
+            std::uint8_t method;
+
+            static constexpr v5_noauth_initial make() noexcept
+            {
+                return {5, 1, v5_noauth_method};
+            }
+        };
+
+        struct v5_auth_initial
+        {
+            std::uint8_t version;
+            std::uint8_t n_methods;
+            std::uint8_t method1;
+            std::uint8_t method2;
+
+            static constexpr v5_auth_initial make() noexcept
+            {
+                return {5, 2, v5_noauth_method, v5_userpass_method};
+            }
+        };
+
+        struct v5_response_initial
+        {
+            std::uint8_t version;
+            std::uint8_t method;
+        };
+
+        struct v5_ipv4_connect
+        {
+            std::uint8_t version;
+            std::uint8_t command;
+            std::uint8_t reserved;
+            std::uint8_t type;
+            boost::endian::big_uint32_t ip;
+            boost::endian::big_uint16_t port;
+
+            static v5_ipv4_connect make(const std::uint32_t ip, const std::uint16_t port) noexcept
+            {
+                return {5, v5_connect_command, v5_reserved, v5_ipv4_type, ip, port};
+            }
+        };
+
+        struct v5_domain_connect
+        {
+            std::uint8_t version;
+            std::uint8_t command;
+            std::uint8_t reserved;
+            std::uint8_t type;
+            std::uint8_t length;
+
+            static constexpr v5_domain_connect make(const std::uint8_t length) noexcept
+            {
+                return {5, v5_connect_command, v5_reserved, v5_domain_type, length};
+            }
+        };
+
+        struct v5_ipv6_connect
+        {
+            std::uint8_t version;
+            std::uint8_t command;
+            std::uint8_t reserved;
+            std::uint8_t type;
+            char ip[16];
+            boost::endian::big_uint16_t port;
+
+            static v5_ipv6_connect make(const boost::asio::ip::address_v6& ip, const std::uint16_t port)
+            {
+                v5_ipv6_connect out{5, v5_connect_command, v5_reserved, v5_ipv6_type};
+                out.port = port;
+
+                const auto ip_bytes = ip.to_bytes();
+                static_assert(sizeof(out.ip) == sizeof(ip_bytes), "unexpected ipv6 bytes size");
+                std::memcpy(std::addressof(out.ip), std::addressof(ip_bytes), sizeof(out.ip));
+
+                return out;
+            }
+        };
+
+        struct v5_response_auth
+        {
+            std::uint8_t version;
+            std::uint8_t status;
+        };
+
+        struct v5_response_connect
+        {
+            std::uint8_t version;
+            std::uint8_t reply;
+            std::uint8_t reserved;
+            std::uint8_t type;
+        };
+
+        struct v5_response_ipv4
+        {
+            boost::endian::big_uint32_t ip;
+            boost::endian::big_uint16_t port;
+        };
+
+        struct v5_response_ipv6
+        {
+            char ip[16];
+            boost::endian::big_uint16_t port;
+        };
+
         std::size_t write_domain_header(epee::span<std::uint8_t> out, const std::uint8_t command, const std::uint16_t port, const boost::string_ref domain)
         {
             if (std::numeric_limits<std::size_t>::max() - sizeof(v4_header) - 2 < domain.size())
@@ -86,6 +207,131 @@ namespace socks
             return buf_size;
         }
 
+        std::size_t write_v5_userpass(epee::span<std::uint8_t> out, const user_and_pass& userinfo)
+        {
+            static constexpr const std::uint8_t max_length = std::numeric_limits<std::uint8_t>::max();
+            if (max_length < userinfo.user.size())
+                return 0;
+            if (max_length < userinfo.pass.size())
+                return 0;
+
+            static_assert(max_length < std::numeric_limits<std::size_t>::max());
+            static_assert(max_length < std::numeric_limits<std::size_t>::max() - max_length);
+            static_assert(3 <= std::numeric_limits<std::size_t>::max() - max_length - max_length);
+
+            if (out.size() < 3 + userinfo.user.size() + userinfo.pass.size())
+                return 0;
+
+            const std::size_t initial = out.size();
+
+            out[0] = v5_userpass_version;
+            out[1] = std::uint8_t(userinfo.user.size());
+            out.remove_prefix(2);
+
+            std::memcpy(out.data(), userinfo.user.data(), userinfo.user.size());
+            out.remove_prefix(userinfo.user.size());
+
+            out[0] = std::uint8_t(userinfo.pass.size());
+            out.remove_prefix(1);
+
+            std::memcpy(out.data(), userinfo.pass.data(), userinfo.pass.size());
+            out.remove_prefix(userinfo.pass.size());
+            return initial - out.size();
+        }
+
+        std::array<std::uint16_t, 2> write_v5_initial(epee::span<std::uint8_t> out, const user_and_pass* userinfo)
+        {
+            std::array<std::uint16_t, 2> sizes{{}};
+
+            if (userinfo && (!userinfo->user.empty() || !userinfo->pass.empty()))
+            {
+                const auto header = v5_auth_initial::make();
+                if (out.size() < sizeof(header))
+                    return sizes;
+                std::memcpy(out.data(), std::addressof(header), sizeof(header));
+                out.remove_prefix(sizeof(header));
+
+                const std::size_t auth = write_v5_userpass(out, *userinfo);
+                if (!auth)
+                    return sizes;
+                out.remove_prefix(auth);
+
+                std::get<0>(sizes) = sizeof(header);
+                std::get<1>(sizes) = auth;
+            }
+            else
+            {
+                const auto header = v5_noauth_initial::make();
+                if (out.size() < sizeof(header))
+                    return sizes;
+                std::memcpy(out.data(), std::addressof(header), sizeof(header));
+                out.remove_prefix(sizeof(header));
+
+                std::get<0>(sizes) = sizeof(header);
+            }
+
+            return sizes;
+        }
+
+        template<typename T>
+        std::array<std::uint16_t, 3> write_v5_address_connect(epee::span<std::uint8_t> out, const T& address, const user_and_pass* userinfo)
+        {
+            std::array<std::uint16_t, 3> sizes{{}};
+
+            const auto result = write_v5_initial(out, userinfo);
+            if (!std::get<0>(result))
+                return sizes;
+
+            for (std::size_t length : result)
+                out.remove_prefix(length);
+
+            if (out.size() < sizeof(address))
+                return sizes;
+            std::memcpy(out.data(), std::addressof(address), sizeof(address));
+
+            std::get<0>(sizes) = std::get<0>(result);
+            std::get<1>(sizes) = std::get<1>(result);
+            std::get<2>(sizes) = sizeof(address);
+            return sizes;
+        }
+
+        std::array<std::uint16_t, 3> write_v5_domain_connect(epee::span<std::uint8_t> out, const std::uint16_t port, const boost::string_ref domain, const user_and_pass* userinfo)
+        {
+            std::array<std::uint16_t, 3> sizes{{}};
+            if (std::numeric_limits<std::uint8_t>::max() < domain.size())
+                return sizes;
+
+            const auto result = write_v5_initial(out, userinfo);
+            if (!std::get<0>(result))
+                return sizes;
+
+            for (std::size_t length : result)
+                out.remove_prefix(length);
+
+            const auto request = v5_domain_connect::make(std::uint8_t(domain.size()));
+            static_assert(sizeof(port) <= std::numeric_limits<std::size_t>::max() - sizeof(request));
+            if (std::numeric_limits<std::size_t>::max() - sizeof(request) - sizeof(port) < domain.size())
+                return sizes;
+
+            const std::size_t last_size = sizeof(request) + sizeof(port) + domain.size();
+            if (out.size() < last_size)
+                return sizes;
+
+            std::memcpy(out.data(), std::addressof(request), sizeof(request));
+            out.remove_prefix(sizeof(request));
+
+            std::memcpy(out.data(), domain.data(), domain.size());
+            out.remove_prefix(domain.size());
+
+            const boost::endian::big_uint16_t big_port{port};
+            std::memcpy(out.data(), std::addressof(big_port), sizeof(big_port));
+
+            std::get<0>(sizes) = std::get<0>(result);
+            std::get<1>(sizes) = std::get<1>(result);
+            std::get<2>(sizes) = last_size;
+            return sizes;
+        }
+
         struct socks_category : boost::system::error_category
         {
             explicit socks_category() noexcept
@@ -101,6 +347,23 @@ namespace socks
             {
                 switch (socks::error(value))
                 {
+                case socks::error::general_failure:
+                    return "Socks general server failure";
+                case socks::error::not_allowed:
+                    return "Socks connection not allowed by ruleset";
+                case socks::error::network_unreachable:
+                    return "Socks network unreachable";
+                case socks::error::host_unreachable:
+                    return "Socks host unreachable";
+                case socks::error::connection_refused:
+                    return "Socks connection refused";
+                case socks::error::ttl_expired:
+                    return "Socks TTL expired";
+                case socks::error::command_not_supported:
+                    return "Socks command not supported";
+                case socks::error::address_type_not_supported:
+                    return "Socks address type not supported";
+
                 case socks::error::rejected:
                     return "Socks request rejected or failed";
                 case socks::error::identd_connection:
@@ -108,6 +371,8 @@ namespace socks
                 case socks::error::identd_user:
                     return "Socks request rejected because the client program and identd report different user-ids";
 
+                case socks::error::auth_failure:
+                    return "Socks authentication failure";
                 case socks::error::bad_read:
                     return "Socks boost::async_read read fewer bytes than expected";
                 case socks::error::bad_write:
@@ -125,6 +390,10 @@ namespace socks
             {
                 switch (socks::error(value))
                 {
+                case socks::error::network_unreachable:
+                    return boost::system::errc::host_unreachable;
+                case socks::error::connection_refused:
+                    return boost::system::errc::connection_refused;
                 case socks::error::bad_read:
                 case socks::error::bad_write:
                     return boost::system::errc::io_error;
@@ -158,18 +427,18 @@ namespace socks
             if (self_)
             {
                 client& self = *self_;
-                self.buffer_size_ = std::min(bytes, sizeof(self.buffer_));
+                std::get<0>(self.buffer_size_) = std::min(bytes, sizeof(self.buffer_));
 
                 if (error)
-                    self.done(error, std::move(self_));
-                else if (self.buffer().size() < sizeof(v4_header))
-                    self.done(socks::error::bad_read, std::move(self_));
+                    self.done(error, self_);
+                else if (std::get<0>(self.buffer_size_) < sizeof(v4_header))
+                    self.done(socks::error::bad_read, self_);
                 else if (self.buffer_[0] != 0) // response version
-                    self.done(socks::error::unexpected_version, std::move(self_));
+                    self.done(socks::error::unexpected_version, self_);
                 else if (self.buffer_[1] != v4_request_granted)
-                    self.done(socks::error(int(self.buffer_[1]) + 1), std::move(self_));
+                    self.done(socks::error(int(self.buffer_[1]) + 1), self_);
                 else
-                    self.done(boost::system::error_code{}, std::move(self_));
+                    self.done(boost::system::error_code{}, self_);
             }
         }
     };
@@ -181,6 +450,7 @@ namespace socks
         static boost::asio::mutable_buffer get_buffer(client& self) noexcept
         {
             static_assert(sizeof(v4_header) <= sizeof(self.buffer_), "buffer too small for v4 response");
+            std::get<0>(self.buffer_size_) = sizeof(v4_header);
             return boost::asio::buffer(self.buffer_, sizeof(v4_header));
         }
 
@@ -190,22 +460,179 @@ namespace socks
             {
                 client& self = *self_;
                 if (error)
-                    self.done(error, std::move(self_));
-                else if (bytes < self.buffer().size())
-                    self.done(socks::error::bad_write, std::move(self_));
+                    self.done(error, self_);
+                else if (bytes < std::get<0>(self.buffer_size_))
+                    self.done(socks::error::bad_write, self_);
                 else
                     boost::asio::async_read(self.proxy_, get_buffer(self), boost::asio::bind_executor(self.strand_, completed{std::move(self_)}));
             }
         }
     };
 
+    struct client::process_v5 : boost::asio::coroutine
+    {
+        std::shared_ptr<client> self_;
+
+        explicit process_v5(std::shared_ptr<client> self)
+          : boost::asio::coroutine(), self_(std::move(self))
+        {}
+
+        static boost::asio::mutable_buffer get_read_buffer(client& self, const std::size_t size)
+        {
+            const std::size_t offset =
+                std::accumulate(self.buffer_size_.begin(), self.buffer_size_.end(), std::size_t(0));
+            if (sizeof(self.buffer_) < offset || sizeof(self.buffer_) - offset < size)
+                throw std::runtime_error{"Not enough room for reading socks v5 buffer"};
+            return boost::asio::buffer(self.buffer_ + offset, size);
+        }
+
+        template<unsigned I>
+        static boost::asio::const_buffer get_write_buffer(const client& self) noexcept
+        {
+            const std::size_t offset =
+                std::accumulate(self.buffer_size_.begin(), self.buffer_size_.begin() + I, std::size_t(0));
+            return boost::asio::buffer(
+                self.buffer_ + offset, std::get<I>(self.buffer_size_)
+            );
+        }
+
+        void operator()(const boost::system::error_code error, std::size_t bytes)
+        {
+            if (!self_)
+                return;
+
+            client& self = *self_;
+            if (error)
+            {
+                self.done(error, self_);
+                return;
+            }
+
+            bool send_userpass = false;
+            BOOST_ASIO_CORO_REENTER(this)
+            {
+                // initial header already written
+
+                BOOST_ASIO_CORO_YIELD boost::asio::async_read(
+                    self.proxy_,
+                    get_read_buffer(self, sizeof(v5_response_initial)),
+                    boost::asio::bind_executor(self.strand_, std::move(*this))
+                );
+                {
+                    v5_response_initial header{};
+
+                    assert(bytes == sizeof(header));
+                    const auto buf = get_read_buffer(self, sizeof(header));
+                    std::memcpy(std::addressof(header), buf.data(), sizeof(header));
+                    if (header.version != 5)
+                    {
+                        self.done(socks::error::unexpected_version, self_);
+                        return;
+                    }
+                    if (header.method != v5_noauth_method && header.method != v5_userpass_method)
+                    {
+                        self.done(socks::error::auth_failure, self_);
+                        return;
+                    }
+                    send_userpass = (header.method == v5_userpass_method);
+                }
+
+                if (send_userpass)
+                {
+                    if (!std::get<1>(self.buffer_size_))
+                    {
+                        self.done(socks::error::auth_failure, self_);
+                        return;
+                    }
+
+                    BOOST_ASIO_CORO_YIELD boost::asio::async_write(
+                        self.proxy_, get_write_buffer<1>(self), boost::asio::bind_executor(self.strand_, std::move(*this))
+                    );
+                    assert(bytes == std::get<1>(self.buffer_size_));
+
+                    BOOST_ASIO_CORO_YIELD boost::asio::async_read(
+                        self.proxy_,
+                        get_read_buffer(self, sizeof(v5_response_auth)),
+                        boost::asio::bind_executor(self.strand_, std::move(*this))
+                    );
+                    {
+                        v5_response_auth header{};
+
+                        assert(bytes == sizeof(header));
+                        const auto buf = get_read_buffer(self, sizeof(header));
+                        std::memcpy(std::addressof(header), buf.data(), sizeof(header));
+                        if (header.version != v5_userpass_version)
+                        {
+                            self.done(socks::error::unexpected_version, self_);
+                            return;
+                        }
+                        if (header.status != v5_reply_success)
+                        {
+                            self.done(socks::error::auth_failure, self_);
+                            return;
+                        }
+                    }
+                }
+
+                BOOST_ASIO_CORO_YIELD boost::asio::async_write(
+                    self.proxy_, get_write_buffer<2>(self), boost::asio::bind_executor(self.strand_, std::move(*this))
+                );
+                assert(bytes == std::get<2>(self.buffer_size_));
+
+                self.buffer_size_ = {};
+                BOOST_ASIO_CORO_YIELD boost::asio::async_read(
+                    self.proxy_,
+                    get_read_buffer(self, sizeof(v5_response_connect)),
+                    boost::asio::bind_executor(self.strand_, std::move(*this))
+                );
+                {
+                    v5_response_connect header{};
+
+                    assert(bytes == sizeof(header));
+                    const auto buf = get_read_buffer(self, sizeof(header));
+                    std::memcpy(std::addressof(header), buf.data(), sizeof(header));
+                    if (header.version != 5)
+                    {
+                        self.done(socks::error::unexpected_version, self_);
+                        return;
+                    }
+                    if (header.reply != v5_reply_success)
+                    {
+                        self.done(socks::error(int(header.reply)), self_);
+                        return;
+                    }
+
+                    if (header.type == v5_ipv4_type)
+                        bytes = sizeof(v5_response_ipv4);
+                    else if (header.type == v5_ipv6_type)
+                        bytes = sizeof(v5_response_ipv6);
+                    else
+                    {
+                        self.done(socks::error::unexpected_version, self_);
+                        return;
+                    }
+                }
+
+                std::get<0>(self.buffer_size_) = sizeof(v5_response_connect);
+                BOOST_ASIO_CORO_YIELD boost::asio::async_read(
+                    self.proxy_,
+                    get_read_buffer(self, bytes),
+                    boost::asio::bind_executor(self.strand_, std::move(*this))
+                );
+                std::get<0>(self.buffer_size_) =
+                    std::min(sizeof(self.buffer_), sizeof(v5_response_connect) + bytes);
+                self.done(error, self_);
+            }
+        }
+    };
+
     struct client::write
     {
         std::shared_ptr<client> self_;
 
         static boost::asio::const_buffer get_buffer(client const& self) noexcept
         {
-            return boost::asio::buffer(self.buffer_, self.buffer_size_);
+            return boost::asio::buffer(self.buffer_, std::get<0>(self.buffer_size_));
         }
 
         void operator()(const boost::system::error_code error)
@@ -214,20 +641,24 @@ namespace socks
             {
                 client& self = *self_;
                 if (error)
-                    self.done(error, std::move(self_));
+                    self.done(error, self_);
+                else if (self.ver_ == version::v5)
+                    boost::asio::async_write(self.proxy_, get_buffer(self), boost::asio::bind_executor(self.strand_, process_v5{std::move(self_)}));
                 else
                     boost::asio::async_write(self.proxy_, get_buffer(self), boost::asio::bind_executor(self.strand_, read{std::move(self_)}));
             }
         }
     };
 
+
+
     client::client(stream_type::socket&& proxy, socks::version ver)
-      : proxy_(std::move(proxy)), strand_(proxy_.get_executor()), buffer_size_(0), buffer_(), ver_(ver)
+      : proxy_(std::move(proxy)), strand_(proxy_.get_executor()), buffer_size_{{}}, buffer_(), ver_(ver)
     {}
 
     client::~client() {}
 
-    bool client::set_connect_command(const epee::net_utils::ipv4_network_address& address)
+    bool client::set_connect_command(const epee::net_utils::ipv4_network_address& address, const user_and_pass* userinfo)
     {
         switch (socks_version())
         {
@@ -235,6 +666,13 @@ namespace socks
         case version::v4a:
         case version::v4a_tor:
             break;
+        case version::v5:
+            buffer_size_ = write_v5_address_connect(
+                buffer_,
+                v5_ipv4_connect::make(boost::endian::big_to_native(address.ip()), address.port()),
+                userinfo
+            );
+            return std::get<0>(buffer_size_) != 0;
         default:
             return false;
         }
@@ -242,43 +680,64 @@ namespace socks
         static_assert(sizeof(v4_header) < sizeof(buffer_), "buffer size too small for request");
         static_assert(0 < sizeof(buffer_), "buffer size too small for null termination"); 
 
+        if (userinfo && (!userinfo->user.empty() || !userinfo->pass.empty()))
+            return false;
+
         // version 4
         const v4_header temp{4, v4_connect_command, address.port(), boost::endian::big_to_native(address.ip())};
         std::memcpy(std::addressof(buffer_), std::addressof(temp), sizeof(temp));
         buffer_[sizeof(temp)] = 0;
-        buffer_size_ = sizeof(temp) + 1;
+
+        buffer_size_ = {};
+        std::get<0>(buffer_size_) = sizeof(temp) + 1;
 
         return true;
     }
 
-    bool client::set_connect_command(const boost::string_ref domain, std::uint16_t port)
+    bool client::set_connect_command(const epee::net_utils::ipv6_network_address& address, const user_and_pass* userinfo)
+    {
+        if (socks_version() != version::v5)
+            return false;
+        buffer_size_ = write_v5_address_connect(
+            buffer_, v5_ipv6_connect::make(address.ip(), address.port()), userinfo
+        );
+        return std::get<0>(buffer_size_) != 0;
+    }
+
+    bool client::set_connect_command(const boost::string_ref domain, std::uint16_t port, const user_and_pass* userinfo)
     {
         switch (socks_version())
         {
         case version::v4a:
         case version::v4a_tor:
             break;
-
+        case version::v5:
+            buffer_size_ = write_v5_domain_connect(buffer_, port, domain, userinfo);
+            return std::get<0>(buffer_size_) != 0;
         default:
             return false;
         }
 
+        if (userinfo && (!userinfo->user.empty() || !userinfo->pass.empty()))
+            return false;
+
         const std::size_t buf_used = write_domain_header(buffer_, v4_connect_command, port, domain);
-        buffer_size_ = buf_used;
+        buffer_size_ = {};
+        std::get<0>(buffer_size_) = buf_used;
         return buf_used != 0;
     }
 
-    bool client::set_connect_command(const net::tor_address& address)
+    bool client::set_connect_command(const net::tor_address& address, const user_and_pass* userinfo)
     {
         if (!address.is_unknown())
-            return set_connect_command(address.host_str(), address.port());
+            return set_connect_command(address.host_str(), address.port(), userinfo);
         return false;
     }
 
-    bool client::set_connect_command(const net::i2p_address& address)
+    bool client::set_connect_command(const net::i2p_address& address, const user_and_pass* userinfo)
     {
         if (!address.is_unknown())
-            return set_connect_command(address.host_str(), address.port());
+            return set_connect_command(address.host_str(), address.port(), userinfo);
         return false;
     }
 
@@ -288,13 +747,14 @@ namespace socks
             return false;
 
         const std::size_t buf_used = write_domain_header(buffer_, v4tor_resolve_command, 0, domain);
-        buffer_size_ = buf_used;
+        buffer_size_ = {};
+        std::get<0>(buffer_size_) = buf_used;
         return buf_used != 0;
     }
 
     bool client::connect_and_send(std::shared_ptr<client> self, const stream_type::endpoint& proxy_address)
     {
-        if (self && !self->buffer().empty())
+        if (self && std::get<0>(self->buffer_size_))
         {
             client& alias = *self;
             alias.proxy_.async_connect(proxy_address, boost::asio::bind_executor(alias.strand_, write{std::move(self)}));
@@ -305,10 +765,13 @@ namespace socks
 
     bool client::send(std::shared_ptr<client> self)
     {
-        if (self && !self->buffer().empty())
+        if (self && std::get<0>(self->buffer_size_))
         {
             client& alias = *self;
-            boost::asio::async_write(alias.proxy_, write::get_buffer(alias), boost::asio::bind_executor(alias.strand_, read{std::move(self)}));
+            if (alias.ver_ == version::v5)
+                boost::asio::async_write(alias.proxy_, write::get_buffer(alias), boost::asio::bind_executor(alias.strand_, process_v5{std::move(self)}));
+            else
+                boost::asio::async_write(alias.proxy_, write::get_buffer(alias), boost::asio::bind_executor(alias.strand_, read{std::move(self)}));
             return true;
         }
         return false;