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Io.net: partial implementation of dns lookup

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This commit is contained in:
Andrew Kelley 2025-09-08 01:06:00 -07:00
parent 4e887625d4
commit e34bb9a413
8 changed files with 754 additions and 394 deletions
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2
lib/std/Io.zig
View file

@ -667,6 +667,8 @@ pub const VTable = struct {
netRead: *const fn (?*anyopaque, src: net.Stream, data: [][]u8) net.Stream.Reader.Error!usize,
netWrite: *const fn (?*anyopaque, dest: net.Stream, header: []const u8, data: []const []const u8, splat: usize) net.Stream.Writer.Error!usize,
netClose: *const fn (?*anyopaque, stream: net.Stream) void,
/// Equivalent to libc "if_nametoindex".
netInterfaceIndex: *const fn (?*anyopaque, name: []const u8) net.InterfaceIndexError!u32,
};
pub const Cancelable = error{

71
lib/std/Io/ThreadPool.zig
View file

@ -135,6 +135,7 @@ pub fn io(pool: *Pool) Io {
else => netWritePosix,
},
.netClose = netClose,
.netInterfaceIndex = netInterfaceIndex,
},
};
}
@ -1122,6 +1123,69 @@ fn netClose(userdata: ?*anyopaque, stream: Io.net.Stream) void {
return net_stream.close();
}
fn netInterfaceIndex(userdata: ?*anyopaque, name: []const u8) Io.net.InterfaceIndexError!u32 {
const pool: *Pool = @ptrCast(@alignCast(userdata));
try pool.checkCancel();
if (native_os == .linux) {
if (name.len >= posix.IFNAMESIZE) return error.InterfaceNotFound;
var ifr: posix.ifreq = undefined;
@memcpy(ifr.ifrn.name[0..name.len], name);
ifr.ifrn.name[name.len] = 0;
const rc = posix.system.socket(posix.AF.UNIX, posix.SOCK.DGRAM | posix.SOCK.CLOEXEC, 0);
const sock_fd: posix.fd_t = switch (posix.errno(rc)) {
.SUCCESS => @intCast(rc),
.ACCES => return error.AccessDenied,
.MFILE => return error.SystemResources,
.NFILE => return error.SystemResources,
.NOBUFS => return error.SystemResources,
.NOMEM => return error.SystemResources,
else => |err| return posix.unexpectedErrno(err),
};
defer posix.close(sock_fd);
while (true) {
try pool.checkCancel();
switch (posix.errno(posix.system.ioctl(sock_fd, posix.SIOCGIFINDEX, @intFromPtr(&ifr)))) {
.SUCCESS => return @bitCast(ifr.ifru.ivalue),
.INVAL => |err| return badErrno(err), // Bad parameters.
.NOTTY => |err| return badErrno(err),
.NXIO => |err| return badErrno(err),
.BADF => |err| return badErrno(err), // Always a race condition.
.FAULT => |err| return badErrno(err), // Bad pointer parameter.
.INTR => continue,
.IO => |err| return badErrno(err), // sock_fd is not a file descriptor
.NODEV => return error.InterfaceNotFound,
else => |err| return posix.unexpectedErrno(err),
}
}
}
if (native_os.isDarwin()) {
if (name.len >= posix.IFNAMESIZE) return error.InterfaceNotFound;
var if_name: [posix.IFNAMESIZE:0]u8 = undefined;
@memcpy(if_name[0..name.len], name);
if_name[name.len] = 0;
const if_slice = if_name[0..name.len :0];
const index = std.c.if_nametoindex(if_slice);
if (index == 0) return error.InterfaceNotFound;
return @bitCast(index);
}
if (native_os == .windows) {
if (name.len >= posix.IFNAMESIZE) return error.InterfaceNotFound;
var interface_name: [posix.IFNAMESIZE:0]u8 = undefined;
@memcpy(interface_name[0..name.len], name);
interface_name[name.len] = 0;
const index = std.os.windows.ws2_32.if_nametoindex(@as([*:0]const u8, &interface_name));
if (index == 0) return error.InterfaceNotFound;
return index;
}
@compileError("std.net.if_nametoindex unimplemented for this OS");
}
const PosixAddress = extern union {
any: posix.sockaddr,
in: posix.sockaddr.in,
@ -1187,3 +1251,10 @@ fn address6ToPosix(a: Io.net.Ip6Address) posix.sockaddr.in6 {
.scope_id = a.scope_id,
};
}
fn badErrno(err: posix.E) Io.UnexpectedError {
switch (builtin.mode) {
.Debug => std.debug.panic("programmer bug caused syscall error: {t}", .{err}),
else => return error.Unexpected,
}
}

306
lib/std/Io/net.zig
View file

@ -4,6 +4,8 @@ const std = @import("../std.zig");
const Io = std.Io;
const assert = std.debug.assert;
pub const HostName = @import("net/HostName.zig");
pub const ListenError = std.net.Address.ListenError || Io.Cancelable;
pub const ListenOptions = struct {
@ -17,298 +19,17 @@ pub const ListenOptions = struct {
force_nonblocking: bool = false,
};
/// An already-validated host name. A valid host name:
/// * Has length less than or equal to `max_len`.
/// * Is valid UTF-8.
/// * Lacks ASCII characters other than alphanumeric, '-', and '.'.
pub const HostName = struct {
/// Externally managed memory. Already checked to be valid.
bytes: []const u8,
pub const max_len = 255;
pub const InitError = error{
NameTooLong,
InvalidHostName,
};
pub fn init(bytes: []const u8) InitError!HostName {
if (bytes.len > max_len) return error.NameTooLong;
if (!std.unicode.utf8ValidateSlice(bytes)) return error.InvalidHostName;
for (bytes) |byte| {
if (!std.ascii.isAscii(byte) or byte == '.' or byte == '-' or std.ascii.isAlphanumeric(byte)) {
continue;
}
return error.InvalidHostName;
}
return .{ .bytes = bytes };
}
pub const LookupOptions = struct {
port: u16,
/// Must have at least length 2.
addresses_buffer: []IpAddress,
/// If a buffer of at least `max_len` is not provided, `lookup` may
/// return successfully with zero-length `LookupResult.canonical_name_len`.
///
/// Suggestion: if not interested in canonical name, pass an empty buffer;
/// otherwise pass a buffer of size `max_len`.
canonical_name_buffer: []u8,
/// `null` means either.
family: ?IpAddress.Tag = null,
};
pub const LookupError = Io.Cancelable || Io.File.OpenError || Io.File.Reader.Error || error{
UnknownHostName,
};
pub const LookupResult = struct {
/// How many `LookupOptions.addresses_buffer` elements are populated.
addresses_len: usize = 0,
canonical_name: ?HostName = null,
};
pub fn lookup(host_name: HostName, io: Io, options: LookupOptions) LookupError!LookupResult {
const name = host_name.bytes;
assert(name.len <= max_len);
assert(options.addresses_buffer.len >= 2);
if (native_os == .windows) @compileError("TODO");
if (builtin.link_libc) @compileError("TODO");
if (native_os == .linux) {
if (options.family != .ip6) {
if (IpAddress.parseIp4(name, options.port)) |addr| {
options.addresses_buffer[0] = addr;
return .{ .addresses_len = 1 };
} else |_| {}
}
if (options.family != .ip4) {
if (IpAddress.parseIp6(name, options.port)) |addr| {
options.addresses_buffer[0] = addr;
return .{ .addresses_len = 1 };
} else |_| {}
}
{
const result = try lookupHosts(host_name, io, options);
if (result.addresses_len > 0) return sortLookupResults(options, result);
}
{
// RFC 6761 Section 6.3.3
// Name resolution APIs and libraries SHOULD recognize
// localhost names as special and SHOULD always return the IP
// loopback address for address queries and negative responses
// for all other query types.
// Check for equal to "localhost(.)" or ends in ".localhost(.)"
const localhost = if (name[name.len - 1] == '.') "localhost." else "localhost";
if (std.mem.endsWith(u8, name, localhost) and
(name.len == localhost.len or name[name.len - localhost.len] == '.'))
{
var i: usize = 0;
if (options.family != .ip6) {
options.addresses_buffer[i] = .{ .ip4 = .localhost(options.port) };
i += 1;
}
if (options.family != .ip4) {
options.addresses_buffer[i] = .{ .ip6 = .localhost(options.port) };
i += 1;
}
const canon_name = "localhost";
const canon_name_dest = options.canonical_name_buffer[0..canon_name.len];
canon_name_dest.* = canon_name.*;
return sortLookupResults(options, .{
.addresses_len = i,
.canonical_name = .{ .bytes = canon_name_dest },
});
}
}
{
const result = try lookupDns(io, options);
if (result.addresses_len > 0) return sortLookupResults(options, result);
}
return error.UnknownHostName;
}
@compileError("unimplemented");
}
fn sortLookupResults(options: LookupOptions, result: LookupResult) !LookupResult {
const addresses = options.addresses_buffer[0..result.addresses_len];
// No further processing is needed if there are fewer than 2 results or
// if there are only IPv4 results.
if (addresses.len < 2) return result;
const all_ip4 = for (addresses) |a| switch (a) {
.ip4 => continue,
.ip6 => break false,
} else true;
if (all_ip4) return result;
// RFC 3484/6724 describes how destination address selection is
// supposed to work. However, to implement it requires making a bunch
// of networking syscalls, which is unnecessarily high latency,
// especially if implemented serially. Furthermore, rules 3, 4, and 7
// have excessive runtime and code size cost and dubious benefit.
//
// Therefore, this logic sorts only using values available without
// doing any syscalls, relying on the calling code to have a
// meta-strategy such as attempting connection to multiple results at
// once and keeping the fastest response while canceling the others.
const S = struct {
pub fn lessThan(s: @This(), lhs: IpAddress, rhs: IpAddress) bool {
return sortKey(s, lhs) < sortKey(s, rhs);
}
fn sortKey(s: @This(), a: IpAddress) i32 {
_ = s;
var da6: Ip6Address = .{
.port = 65535,
.bytes = undefined,
};
switch (a) {
.ip6 => |ip6| {
da6.bytes = ip6.bytes;
da6.scope_id = ip6.scope_id;
},
.ip4 => |ip4| {
da6.bytes[0..12].* = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff".*;
da6.bytes[12..].* = ip4.bytes;
},
}
const da6_scope: i32 = da6.scope();
const da6_prec: i32 = da6.policy().prec;
var key: i32 = 0;
key |= da6_prec << 20;
key |= (15 - da6_scope) << 16;
return key;
}
};
std.mem.sort(IpAddress, addresses, @as(S, .{}), S.lessThan);
return result;
}
fn lookupDns(io: Io, options: LookupOptions) !LookupResult {
_ = io;
_ = options;
@panic("TODO");
}
fn lookupHosts(host_name: HostName, io: Io, options: LookupOptions) !LookupResult {
const file = Io.File.openAbsolute(io, "/etc/hosts", .{}) catch |err| switch (err) {
error.FileNotFound,
error.NotDir,
error.AccessDenied,
=> return .{},
else => |e| return e,
};
defer file.close(io);
var line_buf: [512]u8 = undefined;
var file_reader = file.reader(io, &line_buf);
return lookupHostsReader(host_name, options, &file_reader.interface) catch |err| switch (err) {
error.ReadFailed => return file_reader.err.?,
};
}
fn lookupHostsReader(host_name: HostName, options: LookupOptions, reader: *Io.Reader) error{ReadFailed}!LookupResult {
var addresses_len: usize = 0;
var canonical_name: ?HostName = null;
while (true) {
const line = reader.takeDelimiterExclusive('\n') catch |err| switch (err) {
error.StreamTooLong => {
// Skip lines that are too long.
_ = reader.discardDelimiterInclusive('\n') catch |e| switch (e) {
error.EndOfStream => break,
error.ReadFailed => return error.ReadFailed,
};
continue;
},
error.ReadFailed => return error.ReadFailed,
error.EndOfStream => break,
};
var split_it = std.mem.splitScalar(u8, line, '#');
const no_comment_line = split_it.first();
var line_it = std.mem.tokenizeAny(u8, no_comment_line, " \t");
const ip_text = line_it.next() orelse continue;
var first_name_text: ?[]const u8 = null;
while (line_it.next()) |name_text| {
if (std.mem.eql(u8, name_text, host_name.bytes)) {
if (first_name_text == null) first_name_text = name_text;
break;
}
} else continue;
if (canonical_name == null) {
if (HostName.init(first_name_text.?)) |name_text| {
if (name_text.bytes.len <= options.canonical_name_buffer.len) {
const canonical_name_dest = options.canonical_name_buffer[0..name_text.bytes.len];
@memcpy(canonical_name_dest, name_text.bytes);
canonical_name = .{ .bytes = canonical_name_dest };
}
} else |_| {}
}
if (options.family != .ip6) {
if (IpAddress.parseIp4(ip_text, options.port)) |addr| {
options.addresses_buffer[addresses_len] = addr;
addresses_len += 1;
if (options.addresses_buffer.len - addresses_len == 0) return .{
.addresses_len = addresses_len,
.canonical_name = canonical_name,
};
} else |_| {}
}
if (options.family != .ip4) {
if (IpAddress.parseIp6(ip_text, options.port)) |addr| {
options.addresses_buffer[addresses_len] = addr;
addresses_len += 1;
if (options.addresses_buffer.len - addresses_len == 0) return .{
.addresses_len = addresses_len,
.canonical_name = canonical_name,
};
} else |_| {}
}
}
return .{
.addresses_len = addresses_len,
.canonical_name = canonical_name,
};
}
pub const ConnectTcpError = LookupError || IpAddress.ConnectTcpError;
pub fn connectTcp(host_name: HostName, io: Io, port: u16) ConnectTcpError!Stream {
var addresses_buffer: [32]IpAddress = undefined;
const results = try lookup(host_name, .{
.port = port,
.addresses_buffer = &addresses_buffer,
.canonical_name_buffer = &.{},
});
const addresses = addresses_buffer[0..results.addresses_len];
if (addresses.len == 0) return error.UnknownHostName;
for (addresses) |addr| {
return addr.connectTcp(io) catch |err| switch (err) {
error.ConnectionRefused => continue,
else => |e| return e,
};
}
return error.ConnectionRefused;
}
};
pub const IpAddress = union(enum) {
ip4: Ip4Address,
ip6: Ip6Address,
pub const Tag = @typeInfo(IpAddress).@"union".tag_type.?;
pub const Family = @typeInfo(IpAddress).@"union".tag_type.?;
/// Parse the given IP address string into an `IpAddress` value.
pub fn parse(name: []const u8, port: u16) !IpAddress {
if (parseIp4(name, port)) |ip4| return ip4 else |err| switch (err) {
if (Ip4Address.parse(name, port)) |ip4| {
return .{ .ip4 = ip4 };
} else |err| switch (err) {
error.Overflow,
error.InvalidEnd,
error.InvalidCharacter,
@ -317,7 +38,9 @@ pub const IpAddress = union(enum) {
=> {},
}
if (parseIp6(name, port)) |ip6| return ip6 else |err| switch (err) {
if (Ip6Address.parse(name, port)) |ip6| {
return .{ .ip6 = ip6 };
} else |err| switch (err) {
error.Overflow,
error.InvalidEnd,
error.InvalidCharacter,
@ -859,3 +582,14 @@ pub const Server = struct {
return io.vtable.accept(io, s);
}
};
pub const InterfaceIndexError = error{
InterfaceNotFound,
AccessDenied,
SystemResources,
} || Io.UnexpectedError || Io.Cancelable;
/// Otherwise known as "if_nametoindex".
pub fn interfaceIndex(io: Io, name: []const u8) InterfaceIndexError!u32 {
return io.vtable.netInterfaceIndex(io.userdata, name);
}

631
lib/std/Io/net/HostName.zig Normal file
View file

@ -0,0 +1,631 @@
//! An already-validated host name. A valid host name:
//! * Has length less than or equal to `max_len`.
//! * Is valid UTF-8.
//! * Lacks ASCII characters other than alphanumeric, '-', and '.'.
const HostName = @This();
const builtin = @import("builtin");
const native_os = builtin.os.tag;
const std = @import("../../std.zig");
const Io = std.Io;
const IpAddress = Io.net.IpAddress;
const Ip6Address = Io.net.Ip6Address;
const assert = std.debug.assert;
const Stream = Io.net.Stream;
/// Externally managed memory. Already checked to be valid.
bytes: []const u8,
pub const max_len = 255;
pub const InitError = error{
NameTooLong,
InvalidHostName,
};
pub fn init(bytes: []const u8) InitError!HostName {
if (bytes.len > max_len) return error.NameTooLong;
if (!std.unicode.utf8ValidateSlice(bytes)) return error.InvalidHostName;
for (bytes) |byte| {
if (!std.ascii.isAscii(byte) or byte == '.' or byte == '-' or std.ascii.isAlphanumeric(byte)) {
continue;
}
return error.InvalidHostName;
}
return .{ .bytes = bytes };
}
/// TODO add a retry field here
pub const LookupOptions = struct {
port: u16,
/// Must have at least length 2.
addresses_buffer: []IpAddress,
canonical_name_buffer: *[max_len]u8,
/// `null` means either.
family: ?IpAddress.Family = null,
};
pub const LookupError = Io.Cancelable || Io.File.OpenError || Io.File.Reader.Error || error{
UnknownHostName,
ResolvConfParseFailed,
// TODO remove from error set; retry a few times then report a different error
TemporaryNameServerFailure,
InvalidDnsARecord,
InvalidDnsAAAARecord,
NameServerFailure,
};
pub const LookupResult = struct {
/// How many `LookupOptions.addresses_buffer` elements are populated.
addresses_len: usize,
canonical_name: HostName,
pub const empty: LookupResult = .{
.addresses_len = 0,
.canonical_name = undefined,
};
};
pub fn lookup(host_name: HostName, io: Io, options: LookupOptions) LookupError!LookupResult {
const name = host_name.bytes;
assert(name.len <= max_len);
assert(options.addresses_buffer.len >= 2);
if (native_os == .windows) @compileError("TODO");
if (builtin.link_libc) @compileError("TODO");
if (native_os == .linux) {
if (options.family != .ip6) {
if (IpAddress.parseIp4(name, options.port)) |addr| {
options.addresses_buffer[0] = addr;
return .{ .addresses_len = 1, .canonical_name = copyCanon(options.canonical_name_buffer, name) };
} else |_| {}
}
if (options.family != .ip4) {
if (IpAddress.parseIp6(name, options.port)) |addr| {
options.addresses_buffer[0] = addr;
return .{ .addresses_len = 1, .canonical_name = copyCanon(options.canonical_name_buffer, name) };
} else |_| {}
}
{
const result = try lookupHosts(host_name, io, options);
if (result.addresses_len > 0) return sortLookupResults(options, result);
}
{
// RFC 6761 Section 6.3.3
// Name resolution APIs and libraries SHOULD recognize
// localhost names as special and SHOULD always return the IP
// loopback address for address queries and negative responses
// for all other query types.
// Check for equal to "localhost(.)" or ends in ".localhost(.)"
const localhost = if (name[name.len - 1] == '.') "localhost." else "localhost";
if (std.mem.endsWith(u8, name, localhost) and
(name.len == localhost.len or name[name.len - localhost.len] == '.'))
{
var i: usize = 0;
if (options.family != .ip6) {
options.addresses_buffer[i] = .{ .ip4 = .localhost(options.port) };
i += 1;
}
if (options.family != .ip4) {
options.addresses_buffer[i] = .{ .ip6 = .localhost(options.port) };
i += 1;
}
const canon_name = "localhost";
const canon_name_dest = options.canonical_name_buffer[0..canon_name.len];
canon_name_dest.* = canon_name.*;
return sortLookupResults(options, .{
.addresses_len = i,
.canonical_name = .{ .bytes = canon_name_dest },
});
}
}
{
const result = try lookupDnsSearch(host_name, io, options);
if (result.addresses_len > 0) return sortLookupResults(options, result);
}
return error.UnknownHostName;
}
@compileError("unimplemented");
}
fn sortLookupResults(options: LookupOptions, result: LookupResult) !LookupResult {
const addresses = options.addresses_buffer[0..result.addresses_len];
// No further processing is needed if there are fewer than 2 results or
// if there are only IPv4 results.
if (addresses.len < 2) return result;
const all_ip4 = for (addresses) |a| switch (a) {
.ip4 => continue,
.ip6 => break false,
} else true;
if (all_ip4) return result;
// RFC 3484/6724 describes how destination address selection is
// supposed to work. However, to implement it requires making a bunch
// of networking syscalls, which is unnecessarily high latency,
// especially if implemented serially. Furthermore, rules 3, 4, and 7
// have excessive runtime and code size cost and dubious benefit.
//
// Therefore, this logic sorts only using values available without
// doing any syscalls, relying on the calling code to have a
// meta-strategy such as attempting connection to multiple results at
// once and keeping the fastest response while canceling the others.
const S = struct {
pub fn lessThan(s: @This(), lhs: IpAddress, rhs: IpAddress) bool {
return sortKey(s, lhs) < sortKey(s, rhs);
}
fn sortKey(s: @This(), a: IpAddress) i32 {
_ = s;
var da6: Ip6Address = .{
.port = 65535,
.bytes = undefined,
};
switch (a) {
.ip6 => |ip6| {
da6.bytes = ip6.bytes;
da6.scope_id = ip6.scope_id;
},
.ip4 => |ip4| {
da6.bytes[0..12].* = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff".*;
da6.bytes[12..].* = ip4.bytes;
},
}
const da6_scope: i32 = da6.scope();
const da6_prec: i32 = da6.policy().prec;
var key: i32 = 0;
key |= da6_prec << 20;
key |= (15 - da6_scope) << 16;
return key;
}
};
std.mem.sort(IpAddress, addresses, @as(S, .{}), S.lessThan);
return result;
}
fn lookupDnsSearch(host_name: HostName, io: Io, options: LookupOptions) !LookupResult {
const rc = ResolvConf.init(io) catch return error.ResolvConfParseFailed;
// Count dots, suppress search when >=ndots or name ends in
// a dot, which is an explicit request for global scope.
const dots = std.mem.countScalar(u8, host_name.bytes, '.');
const search_len = if (dots >= rc.ndots or std.mem.endsWith(u8, host_name.bytes, ".")) 0 else rc.search_len;
const search = rc.search_buffer[0..search_len];
var canon_name = host_name.bytes;
// Strip final dot for canon, fail if multiple trailing dots.
if (std.mem.endsWith(u8, canon_name, ".")) canon_name.len -= 1;
if (std.mem.endsWith(u8, canon_name, ".")) return error.UnknownHostName;
// Name with search domain appended is set up in `canon_name`. This
// both provides the desired default canonical name (if the requested
// name is not a CNAME record) and serves as a buffer for passing the
// full requested name to `lookupDns`.
@memcpy(options.canonical_name_buffer[0..canon_name.len], canon_name);
options.canonical_name_buffer[canon_name.len] = '.';
var it = std.mem.tokenizeAny(u8, search, " \t");
while (it.next()) |token| {
@memcpy(options.canonical_name_buffer[canon_name.len + 1 ..][0..token.len], token);
const lookup_canon_name = options.canonical_name_buffer[0 .. canon_name.len + 1 + token.len];
const result = try lookupDns(io, lookup_canon_name, &rc, options);
if (result.addresses_len > 0) return sortLookupResults(options, result);
}
const lookup_canon_name = options.canonical_name_buffer[0..canon_name.len];
return lookupDns(io, lookup_canon_name, &rc, options);
}
fn lookupDns(io: Io, lookup_canon_name: []const u8, rc: *const ResolvConf, options: LookupOptions) !LookupResult {
const family_records: [2]struct { af: IpAddress.Family, rr: u8 } = .{
.{ .af = .ip6, .rr = std.posix.RR.A },
.{ .af = .ip4, .rr = std.posix.RR.AAAA },
};
var query_buffers: [2][280]u8 = undefined;
var queries_buffer: [2][]const u8 = undefined;
var answer_buffers: [2][512]u8 = undefined;
var answers_buffer: [2][]u8 = .{ &answer_buffers[0], &answer_buffers[1] };
var nq: usize = 0;
for (family_records) |fr| {
if (options.family != fr.af) {
const len = writeResolutionQuery(&query_buffers[nq], 0, lookup_canon_name, 1, fr.rr);
queries_buffer[nq] = query_buffers[nq][0..len];
nq += 1;
}
}
const queries = queries_buffer[0..nq];
const replies = answers_buffer[0..nq];
try rc.sendMessage(io, queries, replies);
for (replies) |reply| {
if (reply.len < 4 or (reply[3] & 15) == 2) return error.TemporaryNameServerFailure;
if ((reply[3] & 15) == 3) return .empty;
if ((reply[3] & 15) != 0) return error.UnknownHostName;
}
var addresses_len: usize = 0;
var canonical_name: ?HostName = null;
for (replies) |reply| {
var it = DnsResponse.init(reply) catch {
// TODO accept a diagnostics struct and append warnings
continue;
};
while (it.next() catch {
// TODO accept a diagnostics struct and append warnings
continue;
}) |answer| switch (answer.rr) {
std.posix.RR.A => {
if (answer.data.len != 4) return error.InvalidDnsARecord;
options.addresses_buffer[addresses_len] = .{ .ip4 = .{
.bytes = answer.data[0..4].*,
.port = options.port,
} };
addresses_len += 1;
},
std.posix.RR.AAAA => {
if (answer.data.len != 16) return error.InvalidDnsAAAARecord;
options.addresses_buffer[addresses_len] = .{ .ip6 = .{
.bytes = answer.data[0..16].*,
.port = options.port,
} };
addresses_len += 1;
},
std.posix.RR.CNAME => {
_ = &canonical_name;
@panic("TODO");
//var tmp: [256]u8 = undefined;
//// Returns len of compressed name. strlen to get canon name.
//_ = try posix.dn_expand(packet, answer.data, &tmp);
//const canon_name = mem.sliceTo(&tmp, 0);
//if (isValidHostName(canon_name)) {
// ctx.canon.items.len = 0;
// try ctx.canon.appendSlice(gpa, canon_name);
//}
},
else => continue,
};
}
if (addresses_len != 0) return .{
.addresses_len = addresses_len,
.canonical_name = canonical_name orelse .{ .bytes = lookup_canon_name },
};
return error.NameServerFailure;
}
fn lookupHosts(host_name: HostName, io: Io, options: LookupOptions) !LookupResult {
const file = Io.File.openAbsolute(io, "/etc/hosts", .{}) catch |err| switch (err) {
error.FileNotFound,
error.NotDir,
error.AccessDenied,
=> return .empty,
else => |e| return e,
};
defer file.close(io);
var line_buf: [512]u8 = undefined;
var file_reader = file.reader(io, &line_buf);
return lookupHostsReader(host_name, options, &file_reader.interface) catch |err| switch (err) {
error.ReadFailed => return file_reader.err.?,
};
}
fn lookupHostsReader(host_name: HostName, options: LookupOptions, reader: *Io.Reader) error{ReadFailed}!LookupResult {
var addresses_len: usize = 0;
var canonical_name: ?HostName = null;
while (true) {
const line = reader.takeDelimiterExclusive('\n') catch |err| switch (err) {
error.StreamTooLong => {
// Skip lines that are too long.
_ = reader.discardDelimiterInclusive('\n') catch |e| switch (e) {
error.EndOfStream => break,
error.ReadFailed => return error.ReadFailed,
};
continue;
},
error.ReadFailed => return error.ReadFailed,
error.EndOfStream => break,
};
var split_it = std.mem.splitScalar(u8, line, '#');
const no_comment_line = split_it.first();
var line_it = std.mem.tokenizeAny(u8, no_comment_line, " \t");
const ip_text = line_it.next() orelse continue;
var first_name_text: ?[]const u8 = null;
while (line_it.next()) |name_text| {
if (std.mem.eql(u8, name_text, host_name.bytes)) {
if (first_name_text == null) first_name_text = name_text;
break;
}
} else continue;
if (canonical_name == null) {
if (HostName.init(first_name_text.?)) |name_text| {
if (name_text.bytes.len <= options.canonical_name_buffer.len) {
const canonical_name_dest = options.canonical_name_buffer[0..name_text.bytes.len];
@memcpy(canonical_name_dest, name_text.bytes);
canonical_name = .{ .bytes = canonical_name_dest };
}
} else |_| {}
}
if (options.family != .ip6) {
if (IpAddress.parseIp4(ip_text, options.port)) |addr| {
options.addresses_buffer[addresses_len] = addr;
addresses_len += 1;
if (options.addresses_buffer.len - addresses_len == 0) return .{
.addresses_len = addresses_len,
.canonical_name = canonical_name orelse copyCanon(options.canonical_name_buffer, ip_text),
};
} else |_| {}
}
if (options.family != .ip4) {
if (IpAddress.parseIp6(ip_text, options.port)) |addr| {
options.addresses_buffer[addresses_len] = addr;
addresses_len += 1;
if (options.addresses_buffer.len - addresses_len == 0) return .{
.addresses_len = addresses_len,
.canonical_name = canonical_name orelse copyCanon(options.canonical_name_buffer, ip_text),
};
} else |_| {}
}
}
if (canonical_name == null) assert(addresses_len == 0);
return .{
.addresses_len = addresses_len,
.canonical_name = canonical_name orelse undefined,
};
}
fn copyCanon(canonical_name_buffer: *[max_len]u8, name: []const u8) HostName {
const dest = canonical_name_buffer[0..name.len];
@memcpy(dest, name);
return .{ .bytes = dest };
}
/// Writes DNS resolution query packet data to `w`; at most 280 bytes.
fn writeResolutionQuery(q: *[280]u8, op: u4, dname: []const u8, class: u8, ty: u8) usize {
// This implementation is ported from musl libc.
// A more idiomatic "ziggy" implementation would be welcome.
var name = dname;
if (std.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
@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;
std.crypto.random.bytes(q[0..2]);
return n;
}
pub const ExpandDomainNameError = error{InvalidDnsPacket};
pub fn expandDomainName(
msg: []const u8,
comp_dn: []const u8,
exp_dn: []u8,
) ExpandDomainNameError!usize {
// This implementation is ported from musl libc.
// A more idiomatic "ziggy" implementation would be welcome.
var p = comp_dn.ptr;
var len: usize = std.math.maxInt(usize);
const end = msg.ptr + msg.len;
if (p == end or exp_dn.len == 0) return error.InvalidDnsPacket;
var dest = exp_dn.ptr;
const dend = dest + @min(exp_dn.len, 254);
// detect reference loop using an iteration counter
var i: usize = 0;
while (i < msg.len) : (i += 2) {
// loop invariants: p<end, dest<dend
if ((p[0] & 0xc0) != 0) {
if (p + 1 == end) return error.InvalidDnsPacket;
const j = @as(usize, p[0] & 0x3f) << 8 | p[1];
if (len == std.math.maxInt(usize)) len = @intFromPtr(p) + 2 - @intFromPtr(comp_dn.ptr);
if (j >= msg.len) return error.InvalidDnsPacket;
p = msg.ptr + j;
} else if (p[0] != 0) {
if (dest != exp_dn.ptr) {
dest[0] = '.';
dest += 1;
}
var j = p[0];
p += 1;
if (j >= @intFromPtr(end) - @intFromPtr(p) or j >= @intFromPtr(dend) - @intFromPtr(dest)) {
return error.InvalidDnsPacket;
}
while (j != 0) {
j -= 1;
dest[0] = p[0];
dest += 1;
p += 1;
}
} else {
dest[0] = 0;
if (len == std.math.maxInt(usize)) len = @intFromPtr(p) + 1 - @intFromPtr(comp_dn.ptr);
return len;
}
}
return error.InvalidDnsPacket;
}
pub const DnsResponse = struct {
bytes: []const u8,
pub const Answer = struct {
rr: u8,
data: []const u8,
packet: []const u8,
};
pub const Error = error{InvalidDnsPacket};
pub fn init(r: []const u8) Error!DnsResponse {
if (r.len < 12) return error.InvalidDnsPacket;
return .{ .bytes = r };
}
pub fn next(dr: *DnsResponse) Error!?Answer {
_ = dr;
@panic("TODO");
}
};
pub const ConnectTcpError = LookupError || IpAddress.ConnectTcpError;
pub fn connectTcp(host_name: HostName, io: Io, port: u16) ConnectTcpError!Stream {
var addresses_buffer: [32]IpAddress = undefined;
const results = try lookup(host_name, .{
.port = port,
.addresses_buffer = &addresses_buffer,
.canonical_name_buffer = &.{},
});
const addresses = addresses_buffer[0..results.addresses_len];
if (addresses.len == 0) return error.UnknownHostName;
for (addresses) |addr| {
return addr.connectTcp(io) catch |err| switch (err) {
error.ConnectionRefused => continue,
else => |e| return e,
};
}
return error.ConnectionRefused;
}
pub const ResolvConf = struct {
attempts: u32,
ndots: u32,
timeout: u32,
nameservers_buffer: [3]IpAddress,
nameservers_len: usize,
search_buffer: [max_len]u8,
search_len: usize,
/// Returns `error.StreamTooLong` if a line is longer than 512 bytes.
fn init(io: Io) !ResolvConf {
var rc: ResolvConf = .{
.nameservers_buffer = undefined,
.nameservers_len = 0,
.search_buffer = undefined,
.search_len = 0,
.ndots = 1,
.timeout = 5,
.attempts = 2,
};
const file = Io.File.openAbsolute(io, "/etc/resolv.conf", .{}) catch |err| switch (err) {
error.FileNotFound,
error.NotDir,
error.AccessDenied,
=> {
try addNumeric(&rc, "127.0.0.1", 53);
return rc;
},
else => |e| return e,
};
defer file.close(io);
var line_buf: [512]u8 = undefined;
var file_reader = file.reader(io, &line_buf);
parse(&rc, &file_reader.interface) catch |err| switch (err) {
error.ReadFailed => return file_reader.err.?,
else => |e| return e,
};
return rc;
}
const Directive = enum { options, nameserver, domain, search };
const Option = enum { ndots, attempts, timeout };
fn parse(rc: *ResolvConf, reader: *Io.Reader) !void {
while (reader.takeSentinel('\n')) |line_with_comment| {
const line = line: {
var split = std.mem.splitScalar(u8, line_with_comment, '#');
break :line split.first();
};
var line_it = std.mem.tokenizeAny(u8, line, " \t");
const token = line_it.next() orelse continue;
switch (std.meta.stringToEnum(Directive, token) orelse continue) {
.options => while (line_it.next()) |sub_tok| {
var colon_it = std.mem.splitScalar(u8, sub_tok, ':');
const name = colon_it.first();
const value_txt = colon_it.next() orelse continue;
const value = std.fmt.parseInt(u8, value_txt, 10) catch |err| switch (err) {
error.Overflow => 255,
error.InvalidCharacter => continue,
};
switch (std.meta.stringToEnum(Option, name) orelse continue) {
.ndots => rc.ndots = @min(value, 15),
.attempts => rc.attempts = @min(value, 10),
.timeout => rc.timeout = @min(value, 60),
}
},
.nameserver => {
const ip_txt = line_it.next() orelse continue;
try addNumeric(rc, ip_txt, 53);
},
.domain, .search => {
const rest = line_it.rest();
@memcpy(rc.search_buffer[0..rest.len], rest);
rc.search_len = rest.len;
},
}
} else |err| switch (err) {
error.EndOfStream => if (reader.bufferedLen() != 0) return error.EndOfStream,
else => |e| return e,
}
if (rc.nameservers_len == 0) {
try addNumeric(rc, "127.0.0.1", 53);
}
}
fn addNumeric(rc: *ResolvConf, name: []const u8, port: u16) !void {
assert(rc.nameservers_len < rc.nameservers_buffer.len);
rc.nameservers_buffer[rc.nameservers_len] = try .parse(name, port);
rc.nameservers_len += 1;
}
fn nameservers(rc: *const ResolvConf) []IpAddress {
return rc.nameservers_buffer[0..rc.nameservers_len];
}
fn sendMessage(
rc: *const ResolvConf,
io: Io,
queries: []const []const u8,
answers: [][]u8,
) !void {
_ = rc;
_ = io;
_ = queries;
_ = answers;
@panic("TODO");
}
};

21
lib/std/mem.zig
View file

@ -1678,6 +1678,7 @@ test "indexOfPos empty needle" {
/// needle.len must be > 0
/// does not count overlapping needles
pub fn count(comptime T: type, haystack: []const T, needle: []const T) usize {
if (needle.len == 1) return countScalar(T, haystack, needle[0]);
assert(needle.len > 0);
var i: usize = 0;
var found: usize = 0;
@ -1704,6 +1705,26 @@ test count {
try testing.expect(count(u8, "owowowu", "owowu") == 1);
}
/// Returns the number of times `element` appears in a slice of memory.
pub fn countScalar(comptime T: type, list: []const T, element: T) usize {
var i: usize = 0;
var found: usize = 0;
while (indexOfScalarPos(T, list, i, element)) |next_index| {
i = next_index + 1;
found += 1;
}
return found;
}
test countScalar {
try testing.expect(countScalar(u8, "", 'h') == 0);
try testing.expect(countScalar(u8, "h", 'h') == 1);
try testing.expect(countScalar(u8, "hh", 'h') == 2);
try testing.expect(countScalar(u8, "ahhb", 'h') == 2);
}
/// Returns true if the haystack contains expected_count or more needles
/// needle.len must be > 0
/// does not count overlapping needles

10
lib/std/net.zig
View file

@ -105,7 +105,7 @@ pub const Address = extern union {
=> {},
}
return error.InvalidIPAddressFormat;
return error.InvalidIpAddressFormat;
}
pub fn resolveIp(name: []const u8, port: u16) !Address {
@ -128,7 +128,7 @@ pub const Address = extern union {
else => return err,
}
return error.InvalidIPAddressFormat;
return error.InvalidIpAddressFormat;
}
pub fn parseExpectingFamily(name: []const u8, family: posix.sa_family_t, port: u16) !Address {
@ -360,7 +360,7 @@ pub const Ip4Address = extern struct {
error.NonCanonical,
=> {},
}
return error.InvalidIPAddressFormat;
return error.InvalidIpAddressFormat;
}
pub fn init(addr: [4]u8, port: u16) Ip4Address {
@ -885,7 +885,7 @@ const GetAddressListError = Allocator.Error || File.OpenError || File.ReadError
Overflow,
Incomplete,
InvalidIpv4Mapping,
InvalidIPAddressFormat,
InvalidIpAddressFormat,
InterfaceNotFound,
FileSystem,
@ -1426,7 +1426,7 @@ fn parseHosts(
error.InvalidEnd,
error.InvalidCharacter,
error.Incomplete,
error.InvalidIPAddressFormat,
error.InvalidIpAddressFormat,
error.InvalidIpv4Mapping,
error.NonCanonical,
=> continue,

8
lib/std/net/test.zig
View file

@ -12,10 +12,10 @@ test "parse and render IP addresses at comptime" {
const ipv4addr = net.Address.parseIp("127.0.0.1", 0) catch unreachable;
try std.testing.expectFmt("127.0.0.1:0", "{f}", .{ipv4addr});
try testing.expectError(error.InvalidIPAddressFormat, net.Address.parseIp("::123.123.123.123", 0));
try testing.expectError(error.InvalidIPAddressFormat, net.Address.parseIp("127.01.0.1", 0));
try testing.expectError(error.InvalidIPAddressFormat, net.Address.resolveIp("::123.123.123.123", 0));
try testing.expectError(error.InvalidIPAddressFormat, net.Address.resolveIp("127.01.0.1", 0));
try testing.expectError(error.InvalidIpAddressFormat, net.Address.parseIp("::123.123.123.123", 0));
try testing.expectError(error.InvalidIpAddressFormat, net.Address.parseIp("127.01.0.1", 0));
try testing.expectError(error.InvalidIpAddressFormat, net.Address.resolveIp("::123.123.123.123", 0));
try testing.expectError(error.InvalidIpAddressFormat, net.Address.resolveIp("127.01.0.1", 0));
}
}

99
lib/std/posix.zig
View file

@ -6101,55 +6101,6 @@ pub fn uname() utsname {
}
}
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;
}
pub const SendError = error{
/// (For UNIX domain sockets, which are identified by pathname) Write permission is denied
/// on the destination socket file, or search permission is denied for one of the
@ -6721,56 +6672,6 @@ pub fn recvmsg(
}
}
pub const DnExpandError = error{InvalidDnsPacket};
pub fn dn_expand(
msg: []const u8,
comp_dn: []const u8,
exp_dn: []u8,
) DnExpandError!usize {
// This implementation is ported from musl libc.
// A more idiomatic "ziggy" implementation would be welcome.
var p = comp_dn.ptr;
var len: usize = maxInt(usize);
const end = msg.ptr + msg.len;
if (p == end or exp_dn.len == 0) return error.InvalidDnsPacket;
var dest = exp_dn.ptr;
const dend = dest + @min(exp_dn.len, 254);
// detect reference loop using an iteration counter
var i: usize = 0;
while (i < msg.len) : (i += 2) {
// loop invariants: p<end, dest<dend
if ((p[0] & 0xc0) != 0) {
if (p + 1 == end) return error.InvalidDnsPacket;
const j = @as(usize, p[0] & 0x3f) << 8 | p[1];
if (len == maxInt(usize)) len = @intFromPtr(p) + 2 - @intFromPtr(comp_dn.ptr);
if (j >= msg.len) return error.InvalidDnsPacket;
p = msg.ptr + j;
} else if (p[0] != 0) {
if (dest != exp_dn.ptr) {
dest[0] = '.';
dest += 1;
}
var j = p[0];
p += 1;
if (j >= @intFromPtr(end) - @intFromPtr(p) or j >= @intFromPtr(dend) - @intFromPtr(dest)) {
return error.InvalidDnsPacket;
}
while (j != 0) {
j -= 1;
dest[0] = p[0];
dest += 1;
p += 1;
}
} else {
dest[0] = 0;
if (len == maxInt(usize)) len = @intFromPtr(p) + 1 - @intFromPtr(comp_dn.ptr);
return len;
}
}
return error.InvalidDnsPacket;
}
pub const SetSockOptError = error{
/// The socket is already connected, and a specified option cannot be set while the socket is connected.
AlreadyConnected,