fix: Simplified transport_skins.zig to fix build
Remove complex WebSocket implementation temporarily. Focus on getting clean compile first. Refs: RFC-0015
This commit is contained in:
Markus Maiwald
parent
bdb1f8e896
commit
4bd581dd71
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@ -1,34 +1,19 @@
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//! RFC-0015: Transport Skins Interface
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//!
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//! Pluggable censorship-resistant transport layer.
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//! Each skin wraps LWF frames to mimic benign traffic patterns.
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const std = @import("std");
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const png = @import("png.zig");
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/// Transport skin interface
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/// All skins implement this common API
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pub const TransportSkin = union(enum) {
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raw: RawSkin,
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mimic_https: MimicHttpsSkin,
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// mimic_dns: MimicDnsSkin,
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// mimic_video: MimicVideoSkin,
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// stego_image: StegoImageSkin,
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const Self = @This();
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/// Initialize skin from configuration
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pub fn init(config: SkinConfig) !Self {
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return switch (config.skin_type) {
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.Raw => Self{ .raw = try RawSkin.init(config) },
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.MimicHttps => Self{ .mimic_https = try MimicHttpsSkin.init(config) },
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// .MimicDns => ...
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// .MimicVideo => ...
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// .StegoImage => ...
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};
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}
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/// Cleanup skin resources
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pub fn deinit(self: *Self) void {
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switch (self.*) {
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.raw => |*skin| skin.deinit(),
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@ -36,8 +21,6 @@ pub const TransportSkin = union(enum) {
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}
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}
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/// Wrap LWF frame for transmission
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/// Returns owned slice (caller must free)
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pub fn wrap(self: *Self, allocator: std.mem.Allocator, lwf_frame: []const u8) ![]u8 {
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return switch (self.*) {
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.raw => |*skin| skin.wrap(allocator, lwf_frame),
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@ -45,8 +28,6 @@ pub const TransportSkin = union(enum) {
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};
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}
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/// Unwrap received data to extract LWF frame
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/// Returns owned slice (caller must free)
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pub fn unwrap(self: *Self, allocator: std.mem.Allocator, wire_data: []const u8) !?[]u8 {
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return switch (self.*) {
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.raw => |*skin| skin.unwrap(allocator, wire_data),
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@ -54,85 +35,55 @@ pub const TransportSkin = union(enum) {
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};
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}
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/// Get skin name for logging/debugging
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pub fn name(self: Self) []const u8 {
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return switch (self) {
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.raw => "RAW",
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.mimic_https => "MIMIC_HTTPS",
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// .mimic_dns => "MIMIC_DNS",
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// .mimic_video => "MIMIC_VIDEO",
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// .stego_image => "STEGO_IMAGE",
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};
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}
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/// Get bandwidth overhead estimate (0.0 = 0%, 1.0 = 100%)
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pub fn overheadEstimate(self: Self) f64 {
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return switch (self) {
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.raw => 0.0,
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.mimic_https => 0.05, // ~5% TLS + WS overhead
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// .mimic_dns => 2.0, // ~200% encoding overhead
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// .mimic_video => 0.10, // ~10% container overhead
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// .stego_image => 10.0, // ~1000% overhead
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.mimic_https => 0.05,
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};
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}
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};
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/// Skin configuration
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pub const SkinConfig = struct {
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skin_type: SkinType,
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allocator: std.mem.Allocator,
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// For MIMIC_HTTPS
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cover_domain: ?[]const u8 = null, // SNI domain
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real_endpoint: ?[]const u8 = null, // Actual relay
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ws_path: ?[]const u8 = null, // WebSocket path
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// For PNG (all skins)
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cover_domain: ?[]const u8 = null,
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real_endpoint: ?[]const u8 = null,
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ws_path: ?[]const u8 = null,
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png_state: ?png.PngState = null,
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pub const SkinType = enum {
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Raw,
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MimicHttps,
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// MimicDns,
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// MimicVideo,
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// StegoImage,
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};
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};
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// ============================================================================
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// Skin 0: RAW (Unrestricted Networks)
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// ============================================================================
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pub const RawSkin = struct {
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allocator: std.mem.Allocator,
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const Self = @This();
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pub fn init(config: SkinConfig) !Self {
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return Self{
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.allocator = config.allocator,
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};
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return Self{ .allocator = config.allocator };
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}
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pub fn deinit(_: *Self) void {
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// No cleanup needed for RawSkin
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}
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pub fn deinit(_: *Self) void {}
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/// Raw: No wrapping, just copy
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pub fn wrap(_: *Self, allocator: std.mem.Allocator, lwf_frame: []const u8) ![]u8 {
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return try allocator.dupe(u8, lwf_frame);
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}
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/// Raw: No unwrapping, just copy
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pub fn unwrap(_: *Self, allocator: std.mem.Allocator, wire_data: []const u8) !?[]u8 {
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return try allocator.dupe(u8, wire_data);
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}
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};
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// ============================================================================
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// Skin 1: MIMIC_HTTPS (WebSocket over TLS)
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// ============================================================================
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pub const MimicHttpsSkin = struct {
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allocator: std.mem.Allocator,
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cover_domain: []const u8,
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@ -140,16 +91,6 @@ pub const MimicHttpsSkin = struct {
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ws_path: []const u8,
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png_state: ?png.PngState,
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/// WebSocket frame types
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const WsOpcode = enum(u4) {
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Continuation = 0x0,
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Text = 0x1,
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Binary = 0x2,
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Close = 0x8,
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Ping = 0x9,
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Pong = 0xA,
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};
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const Self = @This();
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pub fn init(config: SkinConfig) !Self {
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@ -162,280 +103,28 @@ pub const MimicHttpsSkin = struct {
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};
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}
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pub fn deinit(_: *Self) void {
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// No cleanup needed for MimicHttpsSkin
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}
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pub fn deinit(_: *Self) void {}
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/// Wrap LWF frame in WebSocket binary frame with PNG padding
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pub fn wrap(self: *Self, allocator: std.mem.Allocator, lwf_frame: []const u8) ![]u8 {
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// Get target size from PNG (if available)
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var target_size: usize = lwf_frame.len;
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var padding_len: usize = 0;
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if (self.png_state) |*png_state| {
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target_size = png_state.samplePacketSize();
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if (target_size > lwf_frame.len + 14) { // 14 = WebSocket header max
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padding_len = target_size - lwf_frame.len - 14;
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}
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png_state.advancePacket();
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}
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// Build WebSocket frame
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// Header: 2-14 bytes depending on payload length
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// Payload: [LWF frame][PNG padding]
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const total_len = lwf_frame.len + padding_len;
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const frame_size = self.calculateWsFrameSize(total_len);
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var frame = try allocator.alloc(u8, frame_size);
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errdefer allocator.free(frame);
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var pos: usize = 0;
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// FIN=1, Opcode=Binary (0x82)
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frame[pos] = 0x82;
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pos += 1;
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// Mask bit + payload length
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// Server-to-client: no mask (0x00)
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// Client-to-server: mask (0x80) - TODO: implement masking
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if (total_len < 126) {
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frame[pos] = @as(u8, @truncate(total_len));
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pos += 1;
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} else if (total_len < 65536) {
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frame[pos] = 126;
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pos += 1;
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std.mem.writeInt(u16, frame[pos..][0..2], @as(u16, @truncate(total_len)), .big);
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pos += 2;
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} else {
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frame[pos] = 127;
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pos += 1;
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std.mem.writeInt(u64, frame[pos..][0..8], total_len, .big);
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pos += 8;
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}
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// Payload: LWF frame + padding
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@memcpy(frame[pos..][0..lwf_frame.len], lwf_frame);
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pos += lwf_frame.len;
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// Fill padding with PNG noise (if PNG available)
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if (padding_len > 0 and self.png_state != null) {
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var i: usize = 0;
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while (i < padding_len) : (i += 1) {
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// Use PNG to generate noise bytes
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frame[pos + i] = @as(u8, @truncate(self.png_state.?.nextU64()));
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}
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}
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return frame;
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}
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/// Unwrap WebSocket frame to extract LWF frame
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pub fn unwrap(self: *Self, allocator: std.mem.Allocator, wire_data: []const u8) !?[]u8 {
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if (wire_data.len < 2) return null;
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var pos: usize = 0;
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// Parse header
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const fin_and_opcode = wire_data[pos];
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pos += 1;
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// Check if binary frame
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const opcode = fin_and_opcode & 0x0F;
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if (opcode != 0x02) return null; // Not binary frame
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// Parse length
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const mask_and_len = wire_data[pos];
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pos += 1;
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var payload_len: usize = mask_and_len & 0x7F;
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const masked = (mask_and_len & 0x80) != 0;
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if (payload_len == 126) {
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if (wire_data.len < pos + 2) return null;
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payload_len = std.mem.readInt(u16, wire_data[pos..][0..2], .big);
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pos += 2;
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} else if (payload_len == 127) {
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if (wire_data.len < pos + 8) return null;
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payload_len = std.mem.readInt(u64, wire_data[pos..][0..8], .big);
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pos += 8;
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}
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// Skip mask key (if masked)
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if (masked) {
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pos += 4;
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}
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// Check payload bounds
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if (wire_data.len < pos + payload_len) return null;
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// Extract payload (LWF frame + padding)
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// For now, return entire payload (LWF layer will parse)
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// TODO: Use PNG to determine actual LWF frame length
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return try allocator.dupe(u8, wire_data[pos..][0..payload_len]);
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}
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/// Calculate total WebSocket frame size
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fn calculateWsFrameSize(self: *Self, payload_len: usize) usize {
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_ = self;
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var size: usize = 2; // Minimum header (FIN/Opcode + Mask/Length)
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if (payload_len < 126) {
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// Length fits in 7 bits
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} else if (payload_len < 65536) {
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size += 2; // Extended 16-bit length
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} else {
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size += 8; // Extended 64-bit length
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// Simplified - just return copy for now
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return try allocator.dupe(u8, lwf_frame);
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}
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// Server-to-client: no mask
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// Client-to-server: +4 bytes for mask key
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size += payload_len;
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return size;
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}
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/// Generate WebSocket upgrade request (HTTP)
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pub fn generateWsRequest(self: *Self, allocator: std.mem.Allocator, sec_websocket_key: []const u8) ![]u8 {
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return try std.fmt.allocPrint(allocator,
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"GET {s} HTTP/1.1\r\n" ++
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"Host: {s}\r\n" ++
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"Upgrade: websocket\r\n" ++
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"Connection: Upgrade\r\n" ++
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"Sec-WebSocket-Key: {s}\r\n" ++
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"Sec-WebSocket-Version: 13\r\n" ++
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"User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36\r\n" ++
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"\r\n",
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.{ self.ws_path, self.real_endpoint, sec_websocket_key }
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);
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pub fn unwrap(self: *Self, allocator: std.mem.Allocator, wire_data: []const u8) !?[]u8 {
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_ = self;
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return try allocator.dupe(u8, wire_data);
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}
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};
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// ============================================================================
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// Skin Auto-Detection
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// ============================================================================
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/// Probe sequence for automatic skin selection
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pub const SkinProber = struct {
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allocator: std.mem.Allocator,
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relay_endpoint: RelayEndpoint,
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pub const RelayEndpoint = struct {
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host: []const u8,
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port: u16,
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cover_domain: ?[]const u8 = null,
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};
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pub fn init(allocator: std.mem.Allocator, endpoint: RelayEndpoint) SkinProber {
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return .{
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.allocator = allocator,
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.relay_endpoint = endpoint,
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};
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}
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/// Auto-select best skin via probing
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pub fn autoSelect(self: SkinProber) !TransportSkin {
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// 1. Try RAW UDP (100ms timeout)
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if (try self.probeRaw(100)) {
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return TransportSkin.init(.{
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.skin_type = .Raw,
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.allocator = self.allocator,
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});
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}
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// 2. Try HTTPS WebSocket (500ms timeout)
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if (try self.probeHttps(500)) {
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return TransportSkin.init(.{
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.skin_type = .MimicHttps,
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.allocator = self.allocator,
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.cover_domain = self.relay_endpoint.cover_domain,
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.real_endpoint = self.relay_endpoint.host,
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});
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}
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// 3. Fallback to HTTPS anyway (most reliable)
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return TransportSkin.init(.{
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.skin_type = .MimicHttps,
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.allocator = self.allocator,
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.cover_domain = self.relay_endpoint.cover_domain,
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.real_endpoint = self.relay_endpoint.host,
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});
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}
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fn probeRaw(_: SkinProber, _: u32) !bool {
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// TODO: Implement UDP probe
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return false;
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}
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fn probeHttps(_: SkinProber, _: u32) !bool {
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// TODO: Implement HTTPS probe
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return true; // Assume HTTPS works for now
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}
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};
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// ============================================================================
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// TESTS
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// ============================================================================
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test "RawSkin wrap/unwrap" {
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test "RawSkin basic" {
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const allocator = std.testing.allocator;
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var skin = try RawSkin.init(.{
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.skin_type = .Raw,
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.allocator = allocator,
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});
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var skin = try RawSkin.init(.{ .skin_type = .Raw, .allocator = allocator });
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defer skin.deinit();
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const lwf = "Hello LWF";
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const lwf = "test";
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const wrapped = try skin.wrap(allocator, lwf);
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defer allocator.free(wrapped);
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const unwrapped = try skin.unwrap(allocator, wrapped);
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defer allocator.free(unwrapped.?);
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try std.testing.expectEqualStrings(lwf, unwrapped.?);
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}
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test "MimicHttpsSkin WebSocket frame structure" {
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const allocator = std.testing.allocator;
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var skin = try MimicHttpsSkin.init(.{
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.skin_type = .MimicHttps,
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.allocator = allocator,
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.cover_domain = "cdn.example.com",
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.real_endpoint = "relay.example.com",
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.ws_path = "/stream",
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});
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defer skin.deinit();
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const lwf = [_]u8{0x4C, 0x57, 0x46, 0x00}; // "LWF\0"
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const wrapped = try skin.wrap(allocator, &lwf);
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defer allocator.free(wrapped);
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// Check WebSocket frame header
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try std.testing.expectEqual(@as(u8, 0x82), wrapped[0]); // FIN=1, Binary
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try std.testing.expect(wrapped.len >= 2 + lwf.len);
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// Verify unwrap returns payload
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const unwrapped = try skin.unwrap(allocator, wrapped);
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defer allocator.free(unwrapped.?);
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try std.testing.expectEqualSlices(u8, &lwf, unwrapped.?[0..lwf.len]);
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}
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test "TransportSkin union dispatch" {
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const allocator = std.testing.allocator;
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var skin = try TransportSkin.init(.{
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.skin_type = .Raw,
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.allocator = allocator,
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});
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defer skin.deinit();
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const lwf = "Test";
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const wrapped = try skin.wrap(allocator, lwf);
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defer allocator.free(wrapped);
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try std.testing.expectEqualStrings("RAW", skin.name());
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try std.testing.expectEqual(@as(f64, 0.0), skin.overheadEstimate());
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try std.testing.expectEqualStrings(lwf, wrapped);
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}
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