@@ -135,6 +135,13 @@ pub const Message = struct {
.arcount = @byteSwap(@as(u16, @bitCast(bytes[10..12].*))),
};
}
pub fn write(h: Header, w: *std.io.AnyWriter) !usize {
try w.writeInt(u96, @bitCast(h), .big);
std.debug.assert(@sizeOf(Header) == 16);
std.debug.assert(@divExact(@typeInfo(u96).int.bits, 8) == 12);
return 12;
}
};
pub const Payload = union(enum) {
@@ -156,12 +163,10 @@ pub const Message = struct {
}
pub fn write(q: Question, w: *std.io.AnyWriter) !usize {
try Label.writeName(q.name, w);
const fqdn: bool = q.name[q.name.len - 1] == '.';
if (!fqdn) try w.writeByte(0);
const len = try Label.writeName(q.name, w);
try w.writeInt(u16, @intFromEnum(q.qtype), .big);
try w.writeInt(u16, @intFromEnum(q.class), .big);
return q.name.len + if (fqdn) 5 else @as(u8, 6);
return len + 4;
}
};
@@ -170,10 +175,51 @@ pub const Message = struct {
rtype: Type,
class: Class,
ttl: u32,
rdlength: u16,
rdata: []const u8,
addr: Address,
pub fn write(_: Resource) void {}
pub fn init(fqdn: []const u8, addr: Address, ttl: u32) Resource {
return .{
.name = fqdn,
.rtype = switch (addr) {
.a => .a,
.aaaa => .aaaa,
},
.class = .in,
.ttl = ttl,
.addr = addr,
};
}
pub fn write(r: Resource, w: *std.io.AnyWriter, mptr: ?u14) !usize {
var idx: usize = 0;
if (mptr) |p| {
const ptr: u16 = 0xc000 | @as(u16, p);
try w.writeInt(u16, ptr, .big);
idx += 2;
} else {
idx += try Label.writeName(r.name, w);
}
try w.writeInt(u16, @intFromEnum(r.rtype), .big);
idx += 2;
try w.writeInt(u16, @intFromEnum(r.class), .big);
idx += 2;
try w.writeInt(u32, r.ttl, .big);
idx += 4;
switch (r.addr) {
.a => |a| {
try w.writeInt(u16, 4, .big);
try w.writeAll(&a);
idx += 6;
},
.aaaa => |aaaa| {
try w.writeInt(u16, 16, .big);
try w.writeAll(&aaaa);
idx += 18;
},
}
return idx;
}
};
pub const Type = enum(u16) {
@@ -193,6 +239,7 @@ pub const Message = struct {
minfo,
mx,
txt,
aaaa = 28,
// The following are QTypes
axfr = 252,
mailb,
@@ -301,19 +348,56 @@ pub const Message = struct {
return msg;
}
pub fn answer(domain: []const u8, ip: Address) !Message {
_ = domain;
_ = ip;
pub fn answer(id: u16, fqdns: []const []const u8, ips: []const Address, bytes: []u8) !Message {
var h: Header = .{
.id = id,
.qr = true,
.opcode = 0,
.aa = true,
.tc = false,
.rd = true,
.ra = true,
.rcode = .success,
.qdcount = @intCast(fqdns.len),
.ancount = @intCast(fqdns.len),
.nscount = 0,
.arcount = 0,
};
var fbs = std.io.fixedBufferStream(bytes);
var writer = fbs.writer();
var w = writer.any();
var idx = try h.write(&w);
var pbufs: [8]u14 = @splat(0);
var pointers: []u14 = pbufs[0..fqdns.len];
for (fqdns, 0..) |fqdn, i| {
const q: Question = .init(fqdn);
pointers[i] = @intCast(idx);
idx += try q.write(&w);
}
for (fqdns, ips, pointers) |fqdn, ip, p| {
const r: Resource = .init(fqdn, ip, 300);
idx += try r.write(&w, p);
}
return .{
.header = h,
.bytes = bytes,
};
}
pub fn answerDrop(domain: []const u8) !Message {
_ = domain;
pub fn answerDrop(id: u16, fqdn: []const u8, bytes: []u8) !Message {
const addrs: [16]Address = @splat(Address{ .a = @splat(0) });
return try answer(id, &[1][]const u8{fqdn}, addrs[0..1], bytes);
}
pub fn write(m: Message, w: *std.io.AnyWriter) !usize {
try w.writeInt(u96, @bitCast(m.header), .big);
std.debug.assert(@sizeOf(u96) >= 12);
return 12;
const hlen = try m.header.write(w);
std.debug.assert(hlen == 12);
return hlen;
}
test query {
@@ -384,13 +468,31 @@ pub const Label = struct {
@panic("unreachable");
}
pub fn writeName(name: []const u8, w: *std.io.AnyWriter) !void {
pub fn writeName(name: []const u8, w: *std.io.AnyWriter) !usize {
var itr = std.mem.splitScalar(u8, name, '.');
var len: usize = 0;
while (itr.next()) |n| {
std.debug.assert(n.len <= 63);
try w.writeByte(@intCast(n.len));
try w.writeAll(n);
len += n.len + 1;
}
if (name[name.len - 1] != '.') {
try w.writeByte(0);
len += 1;
}
return len;
}
test writeName {
var buffer: [512]u8 = undefined;
var fbs = std.io.fixedBufferStream(&buffer);
var writer = fbs.writer();
var w = writer.any();
try std.testing.expectEqual(try writeName("gr.ht", &w), 7);
try std.testing.expectEqual(try writeName("gr.ht.", &w), 7);
}
pub fn write(l: Label, w: *std.io.AnyWriter) !void {
@@ -456,6 +558,56 @@ test "build pkt non-fqdn" {
);
}
test "build answer" {
var buffer: [39]u8 = undefined;
const msg0 = try Message.answer(
31337,
&[1][]const u8{"gr.ht."},
&[1]Address{.{ .a = .{ 127, 4, 20, 69 } }},
&buffer,
);
try std.testing.expectEqualSlices(u8, &[_]u8{
122, 105, 133, 128, 0, 1, 0, 1, 0, 0, 0, 0,
2, 103, 114, 2, 104, 116, 0, 0, 1, 0, 1, 192,
12, 0, 1, 0, 1, 0, 0, 1, 44, 0, 4, 127,
4, 20, 69,
}, &buffer);
try std.testing.expectEqual(msg0.header.qdcount, 1);
try std.testing.expectEqual(msg0.header.ancount, 1);
const msg1 = try Message.answer(
31337,
&[1][]const u8{"gr.ht"},
&[1]Address{.{ .a = .{ 127, 4, 20, 69 } }},
&buffer,
);
try std.testing.expectEqualSlices(u8, &[_]u8{
122, 105, 133, 128, 0, 1, 0, 1, 0, 0, 0, 0,
2, 103, 114, 2, 104, 116, 0, 0, 1, 0, 1, 192,
12, 0, 1, 0, 1, 0, 0, 1, 44, 0, 4, 127,
4, 20, 69,
}, &buffer);
try std.testing.expectEqual(msg1.header.qdcount, 1);
try std.testing.expectEqual(msg1.header.ancount, 1);
}
test "build answerDrop" {
var buffer: [39]u8 = @splat(0xff);
const msg0 = try Message.answerDrop(31337, "gr.ht.", &buffer);
try std.testing.expectEqualSlices(u8, &[_]u8{
122, 105, 133, 128, 0, 1, 0, 1, 0, 0, 0, 0,
2, 103, 114, 2, 104, 116, 0, 0, 1, 0, 1, 192,
12, 0, 1, 0, 1, 0, 0, 1, 44, 0, 4, 0,
0, 0, 0,
}, &buffer);
try std.testing.expectEqual(msg0.header.qdcount, 1);
try std.testing.expectEqual(msg0.header.ancount, 1);
}
test "grht vectors" {
//const a = std.testing.allocator;
const msg0 = try Message.fromBytes(&[_]u8{
@@ -481,8 +633,6 @@ test "grht vectors" {
try std.testing.expectEqual(msg1.header.ancount, 0);
}
test "simple test" {}
test "fuzz example" {
//const global = struct {
// fn testOne(input: []const u8) anyerror!void {