LibCore+RequestServer: Add support for SOCKS5 proxies

6 files changed, 470 insertions, 15 deletions

diff --git a/Userland/Libraries/LibCore/CMakeLists.txt b/Userland/Libraries/LibCore/CMakeLists.txt
index eb3332cab0..fcce16726a 100644
--- a/Userland/Libraries/LibCore/CMakeLists.txt
+++ b/Userland/Libraries/LibCore/CMakeLists.txt
@@ -26,6 +26,7 @@ set(SOURCES
     ProcessStatisticsReader.cpp
     Property.cpp
     SecretString.cpp
+    SOCKSProxyClient.cpp
     Stream.cpp
     StandardPaths.cpp
     System.cpp
diff --git a/Userland/Libraries/LibCore/Proxy.h b/Userland/Libraries/LibCore/Proxy.h
new file mode 100644
index 0000000000..d2fe8f7551
--- /dev/null
+++ b/Userland/Libraries/LibCore/Proxy.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2022, Ali Mohammad Pur <mpfard@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Error.h>
+#include <AK/Types.h>
+#include <LibIPC/Forward.h>
+
+namespace Core {
+// FIXME: Username/password support.
+struct ProxyData {
+    enum Type {
+        Direct,
+        SOCKS5,
+    } type { Type::Direct };
+
+    u32 host_ipv4 { 0 };
+    int port { 0 };
+
+    bool operator==(ProxyData const& other) const = default;
+};
+}
+
+namespace IPC {
+bool encode(Encoder&, Core::ProxyData const&);
+ErrorOr<void> decode(Decoder&, Core::ProxyData&);
+}
diff --git a/Userland/Libraries/LibCore/SOCKSProxyClient.cpp b/Userland/Libraries/LibCore/SOCKSProxyClient.cpp
new file mode 100644
index 0000000000..6368a07f9d
--- /dev/null
+++ b/Userland/Libraries/LibCore/SOCKSProxyClient.cpp
@@ -0,0 +1,325 @@
+/*
+ * Copyright (c) 2022, Ali Mohammad Pur <mpfard@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/MemoryStream.h>
+#include <LibCore/SOCKSProxyClient.h>
+
+enum class Method : u8 {
+    NoAuth = 0x00,
+    GSSAPI = 0x01,
+    UsernamePassword = 0x02,
+    NoAcceptableMethods = 0xFF,
+};
+
+enum class AddressType : u8 {
+    IPV4 = 0x01,
+    DomainName = 0x03,
+    IPV6 = 0x04,
+};
+
+enum class Reply {
+    Succeeded = 0x00,
+    GeneralSocksServerFailure = 0x01,
+    ConnectionNotAllowedByRuleset = 0x02,
+    NetworkUnreachable = 0x03,
+    HostUnreachable = 0x04,
+    ConnectionRefused = 0x05,
+    TTLExpired = 0x06,
+    CommandNotSupported = 0x07,
+    AddressTypeNotSupported = 0x08,
+};
+
+struct [[gnu::packed]] Socks5VersionIdentifierAndMethodSelectionMessage {
+    u8 version_identifier;
+    u8 method_count;
+    // NOTE: We only send a single method, so we don't need to make this variable-length.
+    u8 methods[1];
+};
+
+struct [[gnu::packed]] Socks5InitialResponse {
+    u8 version_identifier;
+    u8 method;
+};
+
+struct [[gnu::packed]] Socks5ConnectRequestHeader {
+    u8 version_identifier;
+    u8 command;
+    u8 reserved;
+};
+
+struct [[gnu::packed]] Socks5ConnectRequestTrailer {
+    u16 port;
+};
+
+struct [[gnu::packed]] Socks5ConnectResponseHeader {
+    u8 version_identifier;
+    u8 status;
+    u8 reserved;
+};
+
+struct [[gnu::packed]] Socks5ConnectResponseTrailer {
+    u8 bind_port;
+};
+
+struct [[gnu::packed]] Socks5UsernamePasswordResponse {
+    u8 version_identifier;
+    u8 status;
+};
+
+namespace {
+StringView reply_response_name(Reply reply)
+{
+    switch (reply) {
+    case Reply::Succeeded:
+        return "Succeeded";
+    case Reply::GeneralSocksServerFailure:
+        return "GeneralSocksServerFailure";
+    case Reply::ConnectionNotAllowedByRuleset:
+        return "ConnectionNotAllowedByRuleset";
+    case Reply::NetworkUnreachable:
+        return "NetworkUnreachable";
+    case Reply::HostUnreachable:
+        return "HostUnreachable";
+    case Reply::ConnectionRefused:
+        return "ConnectionRefused";
+    case Reply::TTLExpired:
+        return "TTLExpired";
+    case Reply::CommandNotSupported:
+        return "CommandNotSupported";
+    case Reply::AddressTypeNotSupported:
+        return "AddressTypeNotSupported";
+    }
+    VERIFY_NOT_REACHED();
+}
+
+ErrorOr<void> send_version_identifier_and_method_selection_message(Core::Stream::Socket& socket, Core::SOCKSProxyClient::Version version, Method method)
+{
+    Socks5VersionIdentifierAndMethodSelectionMessage message {
+        .version_identifier = to_underlying(version),
+        .method_count = 1,
+        .methods = { to_underlying(method) },
+    };
+    auto size = TRY(socket.write({ &message, sizeof(message) }));
+    if (size != sizeof(message))
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to send version identifier and method selection message");
+
+    Socks5InitialResponse response;
+    size = TRY(socket.read({ &response, sizeof(response) }));
+    if (size != sizeof(response))
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to receive initial response");
+
+    if (response.version_identifier != to_underlying(version))
+        return Error::from_string_literal("SOCKS negotiation failed: Invalid version identifier");
+
+    if (response.method != to_underlying(method))
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to negotiate a method");
+
+    return {};
+}
+
+ErrorOr<Reply> send_connect_request_message(Core::Stream::Socket& socket, Core::SOCKSProxyClient::Version version, Core::SOCKSProxyClient::HostOrIPV4 target, int port, Core::SOCKSProxyClient::Command command)
+{
+    DuplexMemoryStream stream;
+
+    Socks5ConnectRequestHeader header {
+        .version_identifier = to_underlying(version),
+        .command = to_underlying(command),
+        .reserved = 0,
+    };
+    Socks5ConnectRequestTrailer trailer {
+        .port = htons(port),
+    };
+
+    auto size = stream.write({ &header, sizeof(header) });
+    if (size != sizeof(header))
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to send connect request header");
+
+    TRY(target.visit(
+        [&](String const& hostname) -> ErrorOr<void> {
+            u8 address_data[2];
+            address_data[0] = to_underlying(AddressType::DomainName);
+            address_data[1] = hostname.length();
+            auto size = stream.write({ address_data, sizeof(address_data) });
+            if (size != array_size(address_data))
+                return Error::from_string_literal("SOCKS negotiation failed: Failed to send connect request address data");
+            stream.write({ hostname.characters(), hostname.length() });
+            return {};
+        },
+        [&](u32 ipv4) -> ErrorOr<void> {
+            u8 address_data[5];
+            address_data[0] = to_underlying(AddressType::IPV4);
+            u32 network_ordered_ipv4 = NetworkOrdered<u32>(ipv4);
+            memcpy(address_data + 1, &network_ordered_ipv4, sizeof(network_ordered_ipv4));
+            auto size = stream.write({ address_data, sizeof(address_data) });
+            if (size != array_size(address_data))
+                return Error::from_string_literal("SOCKS negotiation failed: Failed to send connect request address data");
+            return {};
+        }));
+
+    size = stream.write({ &trailer, sizeof(trailer) });
+    if (size != sizeof(trailer))
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to send connect request trailer");
+
+    auto buffer = stream.copy_into_contiguous_buffer();
+    size = TRY(socket.write({ buffer.data(), buffer.size() }));
+    if (size != buffer.size())
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to send connect request");
+
+    Socks5ConnectResponseHeader response_header;
+    size = TRY(socket.read({ &response_header, sizeof(response_header) }));
+    if (size != sizeof(response_header))
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to receive connect response header");
+
+    if (response_header.version_identifier != to_underlying(version))
+        return Error::from_string_literal("SOCKS negotiation failed: Invalid version identifier");
+
+    u8 response_address_type;
+    size = TRY(socket.read({ &response_address_type, sizeof(response_address_type) }));
+    if (size != sizeof(response_address_type))
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to receive connect response address type");
+
+    switch (AddressType(response_address_type)) {
+    case AddressType::IPV4: {
+        u8 response_address_data[4];
+        size = TRY(socket.read({ response_address_data, sizeof(response_address_data) }));
+        if (size != sizeof(response_address_data))
+            return Error::from_string_literal("SOCKS negotiation failed: Failed to receive connect response address data");
+        break;
+    }
+    case AddressType::DomainName: {
+        u8 response_address_length;
+        size = TRY(socket.read({ &response_address_length, sizeof(response_address_length) }));
+        if (size != sizeof(response_address_length))
+            return Error::from_string_literal("SOCKS negotiation failed: Failed to receive connect response address length");
+        ByteBuffer buffer;
+        buffer.resize(response_address_length);
+        size = TRY(socket.read(buffer));
+        if (size != response_address_length)
+            return Error::from_string_literal("SOCKS negotiation failed: Failed to receive connect response address data");
+        break;
+    }
+    case AddressType::IPV6:
+    default:
+        return Error::from_string_literal("SOCKS negotiation failed: Invalid connect response address type");
+    }
+
+    u16 bound_port;
+    size = TRY(socket.read({ &bound_port, sizeof(bound_port) }));
+    if (size != sizeof(bound_port))
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to receive connect response bound port");
+
+    return Reply(response_header.status);
+}
+
+ErrorOr<u8> send_username_password_authentication_message(Core::Stream::Socket& socket, Core::SOCKSProxyClient::UsernamePasswordAuthenticationData const& auth_data)
+{
+    DuplexMemoryStream stream;
+
+    u8 version = 0x01;
+    auto size = stream.write({ &version, sizeof(version) });
+    if (size != sizeof(version))
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to send username/password authentication message");
+
+    u8 username_length = auth_data.username.length();
+    size = stream.write({ &username_length, sizeof(username_length) });
+    if (size != sizeof(username_length))
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to send username/password authentication message");
+
+    size = stream.write({ auth_data.username.characters(), auth_data.username.length() });
+    if (size != auth_data.username.length())
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to send username/password authentication message");
+
+    u8 password_length = auth_data.password.length();
+    size = stream.write({ &password_length, sizeof(password_length) });
+    if (size != sizeof(password_length))
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to send username/password authentication message");
+
+    size = stream.write({ auth_data.password.characters(), auth_data.password.length() });
+    if (size != auth_data.password.length())
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to send username/password authentication message");
+
+    auto buffer = stream.copy_into_contiguous_buffer();
+    size = TRY(socket.write(buffer));
+    if (size != buffer.size())
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to send username/password authentication message");
+
+    Socks5UsernamePasswordResponse response;
+    size = TRY(socket.read({ &response, sizeof(response) }));
+    if (size != sizeof(response))
+        return Error::from_string_literal("SOCKS negotiation failed: Failed to receive username/password authentication response");
+
+    if (response.version_identifier != version)
+        return Error::from_string_literal("SOCKS negotiation failed: Invalid version identifier");
+
+    return response.status;
+}
+}
+
+namespace Core {
+
+SOCKSProxyClient::~SOCKSProxyClient()
+{
+    close();
+    m_socket.on_ready_to_read = nullptr;
+}
+
+ErrorOr<NonnullOwnPtr<SOCKSProxyClient>> SOCKSProxyClient::connect(Socket& underlying, Version version, HostOrIPV4 const& target, int target_port, Variant<UsernamePasswordAuthenticationData, Empty> const& auth_data, Command command)
+{
+    if (version != Version::V5)
+        return Error::from_string_literal("SOCKS version not supported");
+
+    return auth_data.visit(
+        [&](Empty) -> ErrorOr<NonnullOwnPtr<SOCKSProxyClient>> {
+            TRY(send_version_identifier_and_method_selection_message(underlying, version, Method::NoAuth));
+            auto reply = TRY(send_connect_request_message(underlying, version, target, target_port, command));
+            if (reply != Reply::Succeeded) {
+                underlying.close();
+                return Error::from_string_literal(reply_response_name(reply));
+            }
+
+            return adopt_nonnull_own_or_enomem(new SOCKSProxyClient {
+                underlying,
+                nullptr,
+            });
+        },
+        [&](UsernamePasswordAuthenticationData const& auth_data) -> ErrorOr<NonnullOwnPtr<SOCKSProxyClient>> {
+            TRY(send_version_identifier_and_method_selection_message(underlying, version, Method::UsernamePassword));
+            auto auth_response = TRY(send_username_password_authentication_message(underlying, auth_data));
+            if (auth_response != 0) {
+                underlying.close();
+                return Error::from_string_literal("SOCKS authentication failed");
+            }
+
+            auto reply = TRY(send_connect_request_message(underlying, version, target, target_port, command));
+            if (reply != Reply::Succeeded) {
+                underlying.close();
+                return Error::from_string_literal(reply_response_name(reply));
+            }
+
+            return adopt_nonnull_own_or_enomem(new SOCKSProxyClient {
+                underlying,
+                nullptr,
+            });
+        });
+}
+
+ErrorOr<NonnullOwnPtr<SOCKSProxyClient>> SOCKSProxyClient::connect(HostOrIPV4 const& server, int server_port, Version version, HostOrIPV4 const& target, int target_port, Variant<UsernamePasswordAuthenticationData, Empty> const& auth_data, Command command)
+{
+    auto underlying = TRY(server.visit(
+        [&](u32 ipv4) {
+            return Core::Stream::TCPSocket::connect({ IPv4Address(ipv4), static_cast<u16>(server_port) });
+        },
+        [&](String const& hostname) {
+            return Core::Stream::TCPSocket::connect(hostname, static_cast<u16>(server_port));
+        }));
+
+    auto socket = TRY(connect(*underlying, version, target, target_port, auth_data, command));
+    socket->m_own_underlying_socket = move(underlying);
+    dbgln("SOCKS proxy connected, have {} available bytes", TRY(socket->m_socket.pending_bytes()));
+    return socket;
+}
+
+}
diff --git a/Userland/Libraries/LibCore/SOCKSProxyClient.h b/Userland/Libraries/LibCore/SOCKSProxyClient.h
new file mode 100644
index 0000000000..4b011be0a3
--- /dev/null
+++ b/Userland/Libraries/LibCore/SOCKSProxyClient.h
@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2022, Ali Mohammad Pur <mpfard@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/OwnPtr.h>
+#include <LibCore/Proxy.h>
+#include <LibCore/Stream.h>
+
+namespace Core {
+class SOCKSProxyClient final : public Stream::Socket {
+public:
+    enum class Version : u8 {
+        V4 = 0x04,
+        V5 = 0x05,
+    };
+
+    struct UsernamePasswordAuthenticationData {
+        String username;
+        String password;
+    };
+
+    enum class Command : u8 {
+        Connect = 0x01,
+        Bind = 0x02,
+        UDPAssociate = 0x03,
+    };
+
+    using HostOrIPV4 = Variant<String, u32>;
+
+    static ErrorOr<NonnullOwnPtr<SOCKSProxyClient>> connect(Socket& underlying, Version, HostOrIPV4 const& target, int target_port, Variant<UsernamePasswordAuthenticationData, Empty> const& auth_data = {}, Command = Command::Connect);
+    static ErrorOr<NonnullOwnPtr<SOCKSProxyClient>> connect(HostOrIPV4 const& server, int server_port, Version, HostOrIPV4 const& target, int target_port, Variant<UsernamePasswordAuthenticationData, Empty> const& auth_data = {}, Command = Command::Connect);
+
+    virtual ~SOCKSProxyClient() override;
+
+    // ^Stream::Stream
+    virtual ErrorOr<size_t> read(Bytes bytes) override { return m_socket.read(bytes); }
+    virtual ErrorOr<size_t> write(ReadonlyBytes bytes) override { return m_socket.write(bytes); }
+    virtual bool is_eof() const override { return m_socket.is_eof(); }
+    virtual bool is_open() const override { return m_socket.is_open(); }
+    virtual void close() override { m_socket.close(); }
+
+    // ^Stream::Socket
+    virtual ErrorOr<size_t> pending_bytes() const override { return m_socket.pending_bytes(); }
+    virtual ErrorOr<bool> can_read_without_blocking(int timeout = 0) const override { return m_socket.can_read_without_blocking(timeout); }
+    virtual ErrorOr<void> set_blocking(bool enabled) override { return m_socket.set_blocking(enabled); }
+    virtual ErrorOr<void> set_close_on_exec(bool enabled) override { return m_socket.set_close_on_exec(enabled); }
+    virtual void set_notifications_enabled(bool enabled) override { m_socket.set_notifications_enabled(enabled); }
+
+private:
+    SOCKSProxyClient(Socket& socket, OwnPtr<Socket> own_socket)
+        : m_socket(socket)
+        , m_own_underlying_socket(move(own_socket))
+    {
+        m_socket.on_ready_to_read = [this] { on_ready_to_read(); };
+    }
+
+    Socket& m_socket;
+    OwnPtr<Socket> m_own_underlying_socket;
+};
+}
diff --git a/Userland/Services/RequestServer/ConnectionCache.cpp b/Userland/Services/RequestServer/ConnectionCache.cpp
index fc5aea4c43..7ae813322f 100644
--- a/Userland/Services/RequestServer/ConnectionCache.cpp
+++ b/Userland/Services/RequestServer/ConnectionCache.cpp
@@ -6,11 +6,12 @@
 
 #include "ConnectionCache.h"
 #include <AK/Debug.h>
+#include <AK/Find.h>
 #include <LibCore/EventLoop.h>
 
 namespace RequestServer::ConnectionCache {
 
-HashMap<ConnectionKey, NonnullOwnPtr<NonnullOwnPtrVector<Connection<Core::Stream::TCPSocket>>>> g_tcp_connection_cache {};
+HashMap<ConnectionKey, NonnullOwnPtr<NonnullOwnPtrVector<Connection<Core::Stream::TCPSocket, Core::Stream::Socket>>>> g_tcp_connection_cache {};
 HashMap<ConnectionKey, NonnullOwnPtr<NonnullOwnPtrVector<Connection<TLS::TLSv12>>>> g_tls_connection_cache {};
 
 void request_did_finish(URL const& url, Core::Stream::Socket const* socket)
@@ -22,9 +23,9 @@ void request_did_finish(URL const& url, Core::Stream::Socket const* socket)
 
     dbgln_if(REQUESTSERVER_DEBUG, "Request for {} finished", url);
 
-    ConnectionKey key { url.host(), url.port_or_default() };
+    ConnectionKey partial_key { url.host(), url.port_or_default() };
     auto fire_off_next_job = [&](auto& cache) {
-        auto it = cache.find(key);
+        auto it = find_if(cache.begin(), cache.end(), [&](auto& connection) { return connection.key.hostname == partial_key.hostname && connection.key.port == partial_key.port; });
         if (it == cache.end()) {
             dbgln("Request for URL {} finished, but we don't own that!", url);
             return;
@@ -72,7 +73,7 @@ void request_did_finish(URL const& url, Core::Stream::Socket const* socket)
 
     if (is<Core::Stream::BufferedSocket<TLS::TLSv12>>(socket))
         fire_off_next_job(g_tls_connection_cache);
-    else if (is<Core::Stream::BufferedSocket<Core::Stream::TCPSocket>>(socket))
+    else if (is<Core::Stream::BufferedSocket<Core::Stream::Socket>>(socket))
         fire_off_next_job(g_tcp_connection_cache);
     else
         dbgln("Unknown socket {} finished for URL {}", socket, url);
diff --git a/Userland/Services/RequestServer/ConnectionCache.h b/Userland/Services/RequestServer/ConnectionCache.h
index 3784a91cec..a88bcc4358 100644
--- a/Userland/Services/RequestServer/ConnectionCache.h
+++ b/Userland/Services/RequestServer/ConnectionCache.h
@@ -15,6 +15,7 @@
 #include <LibCore/ElapsedTimer.h>
 #include <LibCore/EventLoop.h>
 #include <LibCore/NetworkJob.h>
+#include <LibCore/SOCKSProxyClient.h>
 #include <LibCore/Timer.h>
 #include <LibTLS/TLSv12.h>
 
@@ -29,7 +30,31 @@ enum class CacheLevel {
 
 namespace RequestServer::ConnectionCache {
 
-template<typename Socket>
+struct Proxy {
+    Core::ProxyData data;
+    OwnPtr<Core::SOCKSProxyClient> proxy_client_storage {};
+
+    template<typename SocketType, typename StorageType, typename... Args>
+    ErrorOr<NonnullOwnPtr<StorageType>> tunnel(URL const& url, Args&&... args)
+    {
+        if (data.type == Core::ProxyData::Direct) {
+            return TRY(SocketType::connect(url.host(), url.port_or_default(), forward<Args>(args)...));
+        }
+        if (data.type == Core::ProxyData::SOCKS5) {
+            if constexpr (requires { SocketType::connect(declval<String>(), *proxy_client_storage, forward<Args>(args)...); }) {
+                proxy_client_storage = TRY(Core::SOCKSProxyClient::connect(data.host_ipv4, data.port, Core::SOCKSProxyClient::Version::V5, url.host(), url.port_or_default()));
+                return TRY(SocketType::connect(url.host(), *proxy_client_storage, forward<Args>(args)...));
+            } else if constexpr (IsSame<SocketType, Core::Stream::TCPSocket>) {
+                return TRY(Core::SOCKSProxyClient::connect(data.host_ipv4, data.port, Core::SOCKSProxyClient::Version::V5, url.host(), url.port_or_default()));
+            } else {
+                return Error::from_string_literal("SOCKS5 not supported for this socket type");
+            }
+        }
+        VERIFY_NOT_REACHED();
+    }
+};
+
+template<typename Socket, typename SocketStorageType = Socket>
 struct Connection {
     struct JobData {
         Function<void(Core::Stream::Socket&)> start {};
@@ -64,19 +89,22 @@ struct Connection {
     };
     using QueueType = Vector<JobData>;
     using SocketType = Socket;
+    using StorageType = SocketStorageType;
 
-    NonnullOwnPtr<Core::Stream::BufferedSocket<Socket>> socket;
+    NonnullOwnPtr<Core::Stream::BufferedSocket<SocketStorageType>> socket;
     QueueType request_queue;
     NonnullRefPtr<Core::Timer> removal_timer;
     bool has_started { false };
     URL current_url {};
     Core::ElapsedTimer timer {};
     JobData job_data {};
+    Proxy proxy {};
 };
 
 struct ConnectionKey {
     String hostname;
     u16 port { 0 };
+    Core::ProxyData proxy_data {};
 
     bool operator==(ConnectionKey const&) const = default;
 };
@@ -87,13 +115,13 @@ template<>
 struct AK::Traits<RequestServer::ConnectionCache::ConnectionKey> : public AK::GenericTraits<RequestServer::ConnectionCache::ConnectionKey> {
     static u32 hash(RequestServer::ConnectionCache::ConnectionKey const& key)
     {
-        return pair_int_hash(key.hostname.hash(), key.port);
+        return pair_int_hash(pair_int_hash(key.proxy_data.host_ipv4, key.proxy_data.port), pair_int_hash(key.hostname.hash(), key.port));
     }
 };
 
 namespace RequestServer::ConnectionCache {
 
-extern HashMap<ConnectionKey, NonnullOwnPtr<NonnullOwnPtrVector<Connection<Core::Stream::TCPSocket>>>> g_tcp_connection_cache;
+extern HashMap<ConnectionKey, NonnullOwnPtr<NonnullOwnPtrVector<Connection<Core::Stream::TCPSocket, Core::Stream::Socket>>>> g_tcp_connection_cache;
 extern HashMap<ConnectionKey, NonnullOwnPtr<NonnullOwnPtrVector<Connection<TLS::TLSv12>>>> g_tls_connection_cache;
 
 void request_did_finish(URL const&, Core::Stream::Socket const*);
@@ -106,10 +134,12 @@ template<typename T>
 ErrorOr<void> recreate_socket_if_needed(T& connection, URL const& url)
 {
     using SocketType = typename T::SocketType;
+    using SocketStorageType = typename T::StorageType;
+
     if (!connection.socket->is_open() || connection.socket->is_eof()) {
         // Create another socket for the connection.
         auto set_socket = [&](auto socket) -> ErrorOr<void> {
-            connection.socket = TRY(Core::Stream::BufferedSocket<SocketType>::create(move(socket)));
+            connection.socket = TRY(Core::Stream::BufferedSocket<SocketStorageType>::create(move(socket)));
             return {};
         };
 
@@ -132,19 +162,21 @@ ErrorOr<void> recreate_socket_if_needed(T& connection, URL const& url)
                     return connection.job_data.provide_client_certificates();
                 return {};
             });
-            TRY(set_socket(TRY(SocketType::connect(url.host(), url.port_or_default(), move(options)))));
+            TRY(set_socket(TRY((connection.proxy.template tunnel<SocketType, SocketStorageType>(url, move(options))))));
         } else {
-            TRY(set_socket(TRY(SocketType::connect(url.host(), url.port_or_default()))));
+            TRY(set_socket(TRY((connection.proxy.template tunnel<SocketType, SocketStorageType>(url)))));
         }
         dbgln_if(REQUESTSERVER_DEBUG, "Creating a new socket for {} -> {}", url, connection.socket);
     }
     return {};
 }
 
-decltype(auto) get_or_create_connection(auto& cache, URL const& url, auto& job)
+decltype(auto) get_or_create_connection(auto& cache, URL const& url, auto& job, Core::ProxyData proxy_data = {})
 {
     using CacheEntryType = RemoveCVReference<decltype(*cache.begin()->value)>;
-    auto& sockets_for_url = *cache.ensure({ url.host(), url.port_or_default() }, [] { return make<CacheEntryType>(); });
+    auto& sockets_for_url = *cache.ensure({ url.host(), url.port_or_default(), proxy_data }, [] { return make<CacheEntryType>(); });
+
+    Proxy proxy { proxy_data };
 
     using ReturnType = decltype(&sockets_for_url[0]);
     auto it = sockets_for_url.find_if([](auto& connection) { return connection->request_queue.is_empty(); });
@@ -152,7 +184,7 @@ decltype(auto) get_or_create_connection(auto& cache, URL const& url, auto& job)
     auto failed_to_find_a_socket = it.is_end();
     if (failed_to_find_a_socket && sockets_for_url.size() < ConnectionCache::MaxConcurrentConnectionsPerURL) {
         using ConnectionType = RemoveCVReference<decltype(cache.begin()->value->at(0))>;
-        auto connection_result = ConnectionType::SocketType::connect(url.host(), url.port_or_default());
+        auto connection_result = proxy.tunnel<typename ConnectionType::SocketType, typename ConnectionType::StorageType>(url);
         if (connection_result.is_error()) {
             dbgln("ConnectionCache: Connection to {} failed: {}", url, connection_result.error());
             Core::deferred_invoke([&job] {
@@ -160,7 +192,7 @@ decltype(auto) get_or_create_connection(auto& cache, URL const& url, auto& job)
             });
             return ReturnType { nullptr };
         }
-        auto socket_result = Core::Stream::BufferedSocket<typename ConnectionType::SocketType>::create(connection_result.release_value());
+        auto socket_result = Core::Stream::BufferedSocket<typename ConnectionType::StorageType>::create(connection_result.release_value());
         if (socket_result.is_error()) {
             dbgln("ConnectionCache: Failed to make a buffered socket for {}: {}", url, socket_result.error());
             Core::deferred_invoke([&job] {
@@ -172,6 +204,7 @@ decltype(auto) get_or_create_connection(auto& cache, URL const& url, auto& job)
             socket_result.release_value(),
             typename ConnectionType::QueueType {},
             Core::Timer::create_single_shot(ConnectionKeepAliveTimeMilliseconds, nullptr)));
+        sockets_for_url.last().proxy = move(proxy);
         did_add_new_connection = true;
     }
     size_t index;