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Robby Zambito
2025-09-09 23:17:32 -04:00
parent c673401c2a
commit 30243db5c9
1 changed files with 161 additions and 33 deletions
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194
src/Client.zig
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@@ -29,47 +29,175 @@ pub fn deinit(self: *Self) void {
/// Used for relay messages and connection handshake.
/// Assumes Client .init has been called.
fn broadcastInitialInterestMessage(self: *Self, msg_bytes: []align(@alignOf(SaprusMessage)) u8) !void {
var packet_bytes: [max_message_size]u8 = comptime blk: {
var b: [max_message_size]u8 = @splat(0);
const writer = self.writer;
// Destination MAC addr to FF:FF:FF:FF:FF:FF
for (0..6) |i| {
b[i] = 0xff;
const UdpHeaders = packed struct {
dest_mac: u48, // [6]u8
src_mac: u48, // [6]u8
ether_type: u16,
ip_version: u4,
header_length: u4,
type_of_service: u8,
total_length: u16,
identification: u16,
ethernet_flags: u3,
fragment_offset: u13,
ttl: u8,
protocol: u8,
header_checksum: u16, // [2]u8
src_ip: u16, // [2]u8
dest_ip: u16, // [2]u8
src_port: u16, // [2]u8
dest_port: u16, // [2]u8
length: u16,
checksum: u16, // [2]u8
fn init(
in: struct {
dest_mac: [6]u8,
src_mac: [6]u8,
ether_type: u16,
ip_version: u4,
header_length: u4 = 0,
type_of_service: u4 = 0,
total_length: usize,
identification: u16 = 0,
ethernet_flags: u3 = 0,
fragment_offset: u13 = 0,
ttl: u8 = 0,
protocol: u8 = 0,
header_checksum: [2]u8 = .{ 0, 0 },
src_ip: [2]u8,
dest_ip: [2]u8,
src_port: [2]u8,
dest_port: [2]u8,
length: usize,
checksum: [2]u8 = .{ 0, 0 },
},
) @This() {
return .{
.dest_mac = @bitCast(in.dest_mac),
.src_mac = @bitCast(in.src_mac),
.ether_type = in.ether_type,
.ip_version = in.ip_version,
.header_length = in.header_length,
.type_of_service = in.type_of_service,
.total_length = @intCast(in.total_length),
.identification = in.identification,
.ethernet_flags = in.ethernet_flags,
.fragment_offset = in.fragment_offset,
.ttl = in.ttl,
.protocol = in.protocol,
.header_checksum = @bitCast(in.header_checksum),
.src_ip = @bitCast(in.src_ip),
.dest_ip = @bitCast(in.dest_ip),
.src_port = @bitCast(in.src_port),
.dest_port = @bitCast(in.dest_port),
.length = @intCast(in.length),
.checksum = @bitCast(in.checksum),
};
}
// Set Ethernet type to IPv4
b[0x0c] = 0x08;
b[0x0d] = 0x00;
// Set IPv4 version to 4
b[0x0e] = 0x45;
// Destination broadcast
for (0x1e..0x22) |i| {
b[i] = 0xff;
}
// Set TTL
b[0x16] = 0x40;
// Set IPv4 protocol to UDP
b[0x17] = 0x11;
// Set interest filter value to 8888.
b[0x24] = 0x22;
b[0x25] = 0xb8;
break :blk b;
};
const total_len = (@bitSizeOf(UdpHeaders) / 8) + msg_bytes.len;
std.debug.assert(writer.buffer.len >= total_len);
_ = writer.consumeAll();
const headers: UdpHeaders = .init(.{
.dest_mac = .{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
.src_mac = blk: {
const r_bytes = try writer.writableArray(6);
self.rand.bytes(r_bytes);
break :blk r_bytes.*;
},
.ether_type = 0x0800,
.ip_version = 0x4,
.header_length = 0x5,
.total_length = total_len - 8, // 8 is the ethernet frame length (macs + type)
.protocol = 0x11,
.src_ip = .{ 0, 0 },
.dest_ip = .{ 0, 0 },
.src_port = .{ 0, 0 },
.dest_port = .{ 0xb8, 0x22 },
.length = msg_bytes.len,
});
_ = try writer.write(&@as([@bitSizeOf(UdpHeaders) / 8]u8, @bitCast(headers)));
// try writer.writeStruct(headers, .big);
// // Ensure buffer is large enough
// std.debug.assert(writer.buffer.len > 38 + msg_bytes.len);
// // Ensure writer is clean
// writer.consumeAll();
// // Destination MAC addr to FF:FF:FF:FF:FF:FF
// try writer.write();
// // Source MAC to random bytes
// {
// }
// // 96 bits
// // Set EtherType to IPv4
// try writer.write(.{ 0x08, 0x00 });
// // 112 bits
// // Set IPv4 version to 4
// try writer.writeByte(0x45);
// // 120 bits
// // Unset section (Version, IHL, ToS)
// writer.advance(2);
// // 136 bits
// // Total length
// try write.writeInt(u16, 38 + msg_bytes.len);
// // Destination broadcast
// writer.splatByte(0xff, 0x22 - 0x1e);
// var packet_bytes: [_]u8 = comptime blk: {
// var b: [max_message_size]u8 = @splat(0);
// for (0x1e..0x22) |i| {
// b[i] = 0xff;
// }
// // Set TTL
// b[0x16] = 0x40;
// // Set IPv4 protocol to UDP
// b[0x17] = 0x11;
// // Set interest filter value to 8888.
// b[0x24] = 0x22;
// b[0x25] = 0xb8;
// break :blk &b;
// };
var msg: *SaprusMessage = try .bytesAsValue(msg_bytes);
try msg.networkFromNativeEndian();
defer msg.nativeFromNetworkEndian() catch unreachable;
// The byte position within the packet that the saprus message starts at.
const saprus_start_byte = 42;
@memcpy(packet_bytes[saprus_start_byte .. saprus_start_byte + msg_bytes.len], msg_bytes);
std.debug.print("headers: {x}\n", .{@as([@bitSizeOf(UdpHeaders) / 8]u8, @bitCast(headers))});
std.debug.print("bytes: {x}\n", .{writer.buffer[0..writer.end]});
_ = try writer.write(msg_bytes);
const writer = self.writer;
_ = try writer.write(packet_bytes[0 .. saprus_start_byte + msg_bytes.len]);
// The byte position within the packet that the saprus message starts at.
// const saprus_start_byte = 42;
// @memcpy(packet_bytes[saprus_start_byte .. saprus_start_byte + msg_bytes.len], msg_bytes);
// _ = try writer.write(packet_bytes[0 .. saprus_start_byte + msg_bytes.len]);
try writer.flush();
}