Prototype
pub fn res_mkquery( op: u4, dname: []const u8, class: u8, ty: u8, data: []const u8, newrr: ?[*]const u8, buf: []u8, ) usize
Source
pub fn res_mkquery(
op: u4,
dname: []const u8,
class: u8,
ty: u8,
data: []const u8,
newrr: ?[*]const u8,
buf: []u8,
) usize {
_ = data;
_ = newrr;
// This implementation is ported from musl libc.
// A more idiomatic "ziggy" implementation would be welcome.
var name = dname;
if (mem.endsWith(u8, name, ".")) name.len -= 1;
assert(name.len <= 253);
const n = 17 + name.len + @intFromBool(name.len != 0);
// Construct query template - ID will be filled later
var q: [280]u8 = undefined;
@memset(q[0..n], 0);
q[2] = @as(u8, op) * 8 + 1;
q[5] = 1;
@memcpy(q[13..][0..name.len], name);
var i: usize = 13;
var j: usize = undefined;
while (q[i] != 0) : (i = j + 1) {
j = i;
while (q[j] != 0 and q[j] != '.') : (j += 1) {}
// TODO determine the circumstances for this and whether or
// not this should be an error.
if (j - i - 1 > 62) unreachable;
q[i - 1] = @intCast(j - i);
}
q[i + 1] = ty;
q[i + 3] = class;
// Make a reasonably unpredictable id
const ts = clock_gettime(.REALTIME) catch unreachable;
const UInt = std.meta.Int(.unsigned, @bitSizeOf(@TypeOf(ts.nsec)));
const unsec: UInt = @bitCast(ts.nsec);
const id: u32 = @truncate(unsec + unsec / 65536);
q[0] = @truncate(id / 256);
q[1] = @truncate(id);
@memcpy(buf[0..n], q[0..n]);
return n;
}