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zig/lib/std/net.zig

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const std = @import("std.zig");
const builtin = @import("builtin");
const assert = std.debug.assert;
const net = @This();
const mem = std.mem;
const os = std.os;
const fs = std.fs;
test "" {
_ = @import("net/test.zig");
}
const has_unix_sockets = @hasDecl(os, "sockaddr_un");
pub const Address = extern union {
any: os.sockaddr,
in: os.sockaddr_in,
in6: os.sockaddr_in6,
un: if (has_unix_sockets) os.sockaddr_un else void,
// TODO this crashed the compiler
//pub const localhost = initIp4(parseIp4("127.0.0.1") catch unreachable, 0);
pub fn parseIp(name: []const u8, port: u16) !Address {
if (parseIp4(name, port)) |ip4| return ip4 else |err| switch (err) {
error.Overflow,
error.InvalidEnd,
error.InvalidCharacter,
error.Incomplete,
=> {},
}
if (parseIp6(name, port)) |ip6| return ip6 else |err| switch (err) {
error.Overflow,
error.InvalidEnd,
error.InvalidCharacter,
error.Incomplete,
error.InvalidIpv4Mapping,
=> {},
}
return error.InvalidIPAddressFormat;
}
pub fn parseExpectingFamily(name: []const u8, family: os.sa_family_t, port: u16) !Address {
switch (family) {
os.AF_INET => return parseIp4(name, port),
os.AF_INET6 => return parseIp6(name, port),
os.AF_UNSPEC => return parseIp(name, port),
else => unreachable,
}
}
pub fn parseIp6(buf: []const u8, port: u16) !Address {
var result = Address{
.in6 = os.sockaddr_in6{
.scope_id = 0,
.port = mem.nativeToBig(u16, port),
.flowinfo = 0,
.addr = undefined,
},
};
var ip_slice = result.in6.addr[0..];
var tail: [16]u8 = undefined;
var x: u16 = 0;
var saw_any_digits = false;
var index: u8 = 0;
var scope_id = false;
var abbrv = false;
for (buf) |c, i| {
if (scope_id) {
if (c >= '0' and c <= '9') {
const digit = c - '0';
if (@mulWithOverflow(u32, result.in6.scope_id, 10, &result.in6.scope_id)) {
return error.Overflow;
}
if (@addWithOverflow(u32, result.in6.scope_id, digit, &result.in6.scope_id)) {
return error.Overflow;
}
} else {
return error.InvalidCharacter;
}
} else if (c == ':') {
if (!saw_any_digits) {
if (abbrv) return error.InvalidCharacter; // ':::'
if (i != 0) abbrv = true;
mem.set(u8, ip_slice[index..], 0);
ip_slice = tail[0..];
index = 0;
continue;
}
if (index == 14) {
return error.InvalidEnd;
}
ip_slice[index] = @truncate(u8, x >> 8);
index += 1;
ip_slice[index] = @truncate(u8, x);
index += 1;
x = 0;
saw_any_digits = false;
} else if (c == '%') {
if (!saw_any_digits) {
return error.InvalidCharacter;
}
scope_id = true;
saw_any_digits = false;
} else if (c == '.') {
if (!abbrv or ip_slice[0] != 0xff or ip_slice[1] != 0xff) {
// must start with '::ffff:'
return error.InvalidIpv4Mapping;
}
const start_index = mem.lastIndexOfScalar(u8, buf[0..i], ':').? + 1;
const addr = (parseIp4(buf[start_index..], 0) catch {
return error.InvalidIpv4Mapping;
}).in.addr;
ip_slice = result.in6.addr[0..];
ip_slice[10] = 0xff;
ip_slice[11] = 0xff;
const ptr = @sliceToBytes(@as(*const [1]u32, &addr)[0..]);
ip_slice[12] = ptr[0];
ip_slice[13] = ptr[1];
ip_slice[14] = ptr[2];
ip_slice[15] = ptr[3];
return result;
} else {
const digit = try std.fmt.charToDigit(c, 16);
if (@mulWithOverflow(u16, x, 16, &x)) {
return error.Overflow;
}
if (@addWithOverflow(u16, x, digit, &x)) {
return error.Overflow;
}
saw_any_digits = true;
}
}
if (!saw_any_digits and !abbrv) {
return error.Incomplete;
}
if (index == 14) {
ip_slice[14] = @truncate(u8, x >> 8);
ip_slice[15] = @truncate(u8, x);
return result;
} else {
ip_slice[index] = @truncate(u8, x >> 8);
index += 1;
ip_slice[index] = @truncate(u8, x);
index += 1;
mem.copy(u8, result.in6.addr[16 - index ..], ip_slice[0..index]);
return result;
}
}
pub fn parseIp4(buf: []const u8, port: u16) !Address {
var result = Address{
.in = os.sockaddr_in{
.port = mem.nativeToBig(u16, port),
.addr = undefined,
},
};
const out_ptr = @sliceToBytes(@as(*[1]u32, &result.in.addr)[0..]);
var x: u8 = 0;
var index: u8 = 0;
var saw_any_digits = false;
for (buf) |c| {
if (c == '.') {
if (!saw_any_digits) {
return error.InvalidCharacter;
}
if (index == 3) {
return error.InvalidEnd;
}
out_ptr[index] = x;
index += 1;
x = 0;
saw_any_digits = false;
} else if (c >= '0' and c <= '9') {
saw_any_digits = true;
x = try std.math.mul(u8, x, 10);
x = try std.math.add(u8, x, c - '0');
} else {
return error.InvalidCharacter;
}
}
if (index == 3 and saw_any_digits) {
out_ptr[index] = x;
return result;
}
return error.Incomplete;
}
pub fn initIp4(addr: [4]u8, port: u16) Address {
return Address{
.in = os.sockaddr_in{
.port = mem.nativeToBig(u16, port),
.addr = @ptrCast(*align(1) const u32, &addr).*,
},
};
}
pub fn initIp6(addr: [16]u8, port: u16, flowinfo: u32, scope_id: u32) Address {
return Address{
.in6 = os.sockaddr_in6{
.addr = addr,
.port = mem.nativeToBig(u16, port),
.flowinfo = flowinfo,
.scope_id = scope_id,
},
};
}
pub fn initUnix(path: []const u8) !Address {
var sock_addr = os.sockaddr_un{
.family = os.AF_UNIX,
.path = undefined,
};
// this enables us to have the proper length of the socket in getOsSockLen
mem.set(u8, &sock_addr.path, 0);
if (path.len > sock_addr.path.len) return error.NameTooLong;
mem.copy(u8, &sock_addr.path, path);
return Address{ .un = sock_addr };
}
/// Returns the port in native endian.
/// Asserts that the address is ip4 or ip6.
pub fn getPort(self: Address) u16 {
const big_endian_port = switch (self.any.family) {
os.AF_INET => self.in.port,
os.AF_INET6 => self.in6.port,
else => unreachable,
};
return mem.bigToNative(u16, big_endian_port);
}
/// `port` is native-endian.
/// Asserts that the address is ip4 or ip6.
pub fn setPort(self: *Address, port: u16) void {
const ptr = switch (self.any.family) {
os.AF_INET => &self.in.port,
os.AF_INET6 => &self.in6.port,
else => unreachable,
};
ptr.* = mem.nativeToBig(u16, port);
}
/// Asserts that `addr` is an IP address.
/// This function will read past the end of the pointer, with a size depending
/// on the address family.
pub fn initPosix(addr: *align(4) const os.sockaddr) Address {
switch (addr.family) {
os.AF_INET => return Address{ .in = @ptrCast(*const os.sockaddr_in, addr).* },
os.AF_INET6 => return Address{ .in6 = @ptrCast(*const os.sockaddr_in6, addr).* },
else => unreachable,
}
}
pub fn format(
self: Address,
comptime fmt: []const u8,
options: std.fmt.FormatOptions,
context: var,
comptime Errors: type,
output: fn (@TypeOf(context), []const u8) Errors!void,
) !void {
switch (self.any.family) {
os.AF_INET => {
const port = mem.bigToNative(u16, self.in.port);
const bytes = @ptrCast(*const [4]u8, &self.in.addr);
try std.fmt.format(context, Errors, output, "{}.{}.{}.{}:{}", .{
bytes[0],
bytes[1],
bytes[2],
bytes[3],
port,
});
},
os.AF_INET6 => {
const port = mem.bigToNative(u16, self.in6.port);
if (mem.eql(u8, self.in6.addr[0..12], &[_]u8{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff })) {
try std.fmt.format(context, Errors, output, "[::ffff:{}.{}.{}.{}]:{}", .{
self.in6.addr[12],
self.in6.addr[13],
self.in6.addr[14],
self.in6.addr[15],
port,
});
return;
}
const big_endian_parts = @ptrCast(*align(1) const [8]u16, &self.in6.addr);
const native_endian_parts = switch (builtin.endian) {
.Big => big_endian_parts.*,
.Little => blk: {
var buf: [8]u16 = undefined;
for (big_endian_parts) |part, i| {
buf[i] = mem.bigToNative(u16, part);
}
break :blk buf;
},
};
try output(context, "[");
var i: usize = 0;
var abbrv = false;
while (i < native_endian_parts.len) : (i += 1) {
if (native_endian_parts[i] == 0) {
if (!abbrv) {
try output(context, if (i == 0) "::" else ":");
abbrv = true;
}
continue;
}
try std.fmt.format(context, Errors, output, "{x}", .{native_endian_parts[i]});
if (i != native_endian_parts.len - 1) {
try output(context, ":");
}
}
try std.fmt.format(context, Errors, output, "]:{}", .{port});
},
os.AF_UNIX => {
if (!has_unix_sockets) {
unreachable;
}
try std.fmt.format(context, Errors, output, "{}", .{&self.un.path});
},
else => unreachable,
}
}
pub fn eql(a: Address, b: Address) bool {
const a_bytes = @ptrCast([*]const u8, &a.any)[0..a.getOsSockLen()];
const b_bytes = @ptrCast([*]const u8, &b.any)[0..b.getOsSockLen()];
return mem.eql(u8, a_bytes, b_bytes);
}
fn getOsSockLen(self: Address) os.socklen_t {
switch (self.any.family) {
os.AF_INET => return @sizeOf(os.sockaddr_in),
os.AF_INET6 => return @sizeOf(os.sockaddr_in6),
os.AF_UNIX => {
if (!has_unix_sockets) {
unreachable;
}
const path_len = std.mem.len(u8, @ptrCast([*:0]const u8, &self.un.path));
return @intCast(os.socklen_t, @sizeOf(os.sockaddr_un) - self.un.path.len + path_len);
},
else => unreachable,
}
}
};
pub fn connectUnixSocket(path: []const u8) !fs.File {
const opt_non_block = if (std.io.mode == .evented) os.SOCK_NONBLOCK else 0;
const sockfd = try os.socket(
os.AF_UNIX,
os.SOCK_STREAM | os.SOCK_CLOEXEC | opt_non_block,
0,
);
errdefer os.close(sockfd);
var addr = try std.net.Address.initUnix(path);
try os.connect(
sockfd,
&addr.any,
addr.getOsSockLen(),
);
return fs.File.openHandle(sockfd);
}
pub const AddressList = struct {
arena: std.heap.ArenaAllocator,
addrs: []Address,
canon_name: ?[]u8,
fn deinit(self: *AddressList) void {
// Here we copy the arena allocator into stack memory, because
// otherwise it would destroy itself while it was still working.
var arena = self.arena;
arena.deinit();
// self is destroyed
}
};
/// All memory allocated with `allocator` will be freed before this function returns.
pub fn tcpConnectToHost(allocator: *mem.Allocator, name: []const u8, port: u16) !fs.File {
const list = getAddressList(allocator, name, port);
defer list.deinit();
const addrs = list.addrs.toSliceConst();
if (addrs.len == 0) return error.UnknownHostName;
return tcpConnectToAddress(addrs[0], port);
}
pub fn tcpConnectToAddress(address: Address) !fs.File {
const nonblock = if (std.io.is_async) os.SOCK_NONBLOCK else 0;
const sock_flags = os.SOCK_STREAM | os.SOCK_CLOEXEC | nonblock;
const sockfd = try os.socket(address.any.family, sock_flags, os.IPPROTO_TCP);
errdefer os.close(sockfd);
try os.connect(sockfd, &address.any, address.getOsSockLen());
return fs.File{ .handle = sockfd };
}
/// Call `AddressList.deinit` on the result.
pub fn getAddressList(allocator: *mem.Allocator, name: []const u8, port: u16) !*AddressList {
const result = blk: {
var arena = std.heap.ArenaAllocator.init(allocator);
errdefer arena.deinit();
const result = try arena.allocator.create(AddressList);
result.* = AddressList{
.arena = arena,
.addrs = undefined,
.canon_name = null,
};
break :blk result;
};
const arena = &result.arena.allocator;
errdefer result.arena.deinit();
if (builtin.link_libc) {
const c = std.c;
const name_c = try std.cstr.addNullByte(allocator, name);
defer allocator.free(name_c);
const port_c = try std.fmt.allocPrint(allocator, "{}\x00", .{port});
defer allocator.free(port_c);
const hints = os.addrinfo{
.flags = c.AI_NUMERICSERV,
.family = os.AF_UNSPEC,
.socktype = os.SOCK_STREAM,
.protocol = os.IPPROTO_TCP,
.canonname = null,
.addr = null,
.addrlen = 0,
.next = null,
};
var res: *os.addrinfo = undefined;
switch (os.system.getaddrinfo(
name_c.ptr,
@ptrCast([*:0]const u8, port_c.ptr),
&hints,
&res)) {
0 => {},
c.EAI_ADDRFAMILY => return error.HostLacksNetworkAddresses,
c.EAI_AGAIN => return error.TemporaryNameServerFailure,
c.EAI_BADFLAGS => unreachable, // Invalid hints
c.EAI_FAIL => return error.NameServerFailure,
c.EAI_FAMILY => return error.AddressFamilyNotSupported,
c.EAI_MEMORY => return error.OutOfMemory,
c.EAI_NODATA => return error.HostLacksNetworkAddresses,
c.EAI_NONAME => return error.UnknownHostName,
c.EAI_SERVICE => return error.ServiceUnavailable,
c.EAI_SOCKTYPE => unreachable, // Invalid socket type requested in hints
c.EAI_SYSTEM => switch (os.errno(-1)) {
else => |e| return os.unexpectedErrno(e),
},
else => unreachable,
}
defer os.system.freeaddrinfo(res);
const addr_count = blk: {
var count: usize = 0;
var it: ?*os.addrinfo = res;
while (it) |info| : (it = info.next) {
if (info.addr != null) {
count += 1;
}
}
break :blk count;
};
result.addrs = try arena.alloc(Address, addr_count);
var it: ?*os.addrinfo = res;
var i: usize = 0;
while (it) |info| : (it = info.next) {
const addr = info.addr orelse continue;
result.addrs[i] = Address.initPosix(@alignCast(4, addr));
if (info.canonname) |n| {
if (result.canon_name == null) {
result.canon_name = try mem.dupe(arena, u8, mem.toSliceConst(u8, n));
}
}
i += 1;
}
return result;
}
if (builtin.os == .linux) {
const flags = std.c.AI_NUMERICSERV;
const family = os.AF_UNSPEC;
var lookup_addrs = std.ArrayList(LookupAddr).init(allocator);
defer lookup_addrs.deinit();
var canon = std.Buffer.initNull(arena);
defer canon.deinit();
try linuxLookupName(&lookup_addrs, &canon, name, family, flags, port);
result.addrs = try arena.alloc(Address, lookup_addrs.len);
if (!canon.isNull()) {
result.canon_name = canon.toOwnedSlice();
}
for (lookup_addrs.toSliceConst()) |lookup_addr, i| {
result.addrs[i] = lookup_addr.addr;
assert(result.addrs[i].getPort() == port);
}
return result;
}
@compileError("std.net.getAddresses unimplemented for this OS");
}
const LookupAddr = struct {
addr: Address,
sortkey: i32 = 0,
};
const DAS_USABLE = 0x40000000;
const DAS_MATCHINGSCOPE = 0x20000000;
const DAS_MATCHINGLABEL = 0x10000000;
const DAS_PREC_SHIFT = 20;
const DAS_SCOPE_SHIFT = 16;
const DAS_PREFIX_SHIFT = 8;
const DAS_ORDER_SHIFT = 0;
fn linuxLookupName(
addrs: *std.ArrayList(LookupAddr),
canon: *std.Buffer,
opt_name: ?[]const u8,
family: os.sa_family_t,
flags: u32,
port: u16,
) !void {
if (opt_name) |name| {
// reject empty name and check len so it fits into temp bufs
try canon.replaceContents(name);
if (Address.parseExpectingFamily(name, family, port)) |addr| {
try addrs.append(LookupAddr{ .addr = addr });
} else |name_err| if ((flags & std.c.AI_NUMERICHOST) != 0) {
return name_err;
} else {
try linuxLookupNameFromHosts(addrs, canon, name, family, port);
if (addrs.len == 0) {
try linuxLookupNameFromDnsSearch(addrs, canon, name, family, port);
}
}
} else {
try canon.resize(0);
try linuxLookupNameFromNull(addrs, family, flags, port);
}
if (addrs.len == 0) return error.UnknownHostName;
// No further processing is needed if there are fewer than 2
// results or if there are only IPv4 results.
if (addrs.len == 1 or family == os.AF_INET) return;
const all_ip4 = for (addrs.toSliceConst()) |addr| {
if (addr.addr.any.family != os.AF_INET) break false;
} else true;
if (all_ip4) return;
// The following implements a subset of RFC 3484/6724 destination
// address selection by generating a single 31-bit sort key for
// each address. Rules 3, 4, and 7 are omitted for having
// excessive runtime and code size cost and dubious benefit.
// So far the label/precedence table cannot be customized.
// This implementation is ported from musl libc.
// A more idiomatic "ziggy" implementation would be welcome.
for (addrs.toSlice()) |*addr, i| {
var key: i32 = 0;
var sa6: os.sockaddr_in6 = undefined;
@memset(@ptrCast([*]u8, &sa6), 0, @sizeOf(os.sockaddr_in6));
var da6 = os.sockaddr_in6{
.family = os.AF_INET6,
.scope_id = addr.addr.in6.scope_id,
.port = 65535,
.flowinfo = 0,
.addr = [1]u8{0} ** 16,
};
var sa4: os.sockaddr_in = undefined;
@memset(@ptrCast([*]u8, &sa4), 0, @sizeOf(os.sockaddr_in));
var da4 = os.sockaddr_in{
.family = os.AF_INET,
.port = 65535,
.addr = 0,
.zero = [1]u8{0} ** 8,
};
var sa: *align(4) os.sockaddr = undefined;
var da: *align(4) os.sockaddr = undefined;
var salen: os.socklen_t = undefined;
var dalen: os.socklen_t = undefined;
if (addr.addr.any.family == os.AF_INET6) {
mem.copy(u8, &da6.addr, &addr.addr.in6.addr);
da = @ptrCast(*os.sockaddr, &da6);
dalen = @sizeOf(os.sockaddr_in6);
sa = @ptrCast(*os.sockaddr, &sa6);
salen = @sizeOf(os.sockaddr_in6);
} else {
mem.copy(u8, &sa6.addr, "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff");
mem.copy(u8, &da6.addr, "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff");
// TODO https://github.com/ziglang/zig/issues/863
mem.writeIntNative(u32, @ptrCast(*[4]u8, da6.addr[12..].ptr), addr.addr.in.addr);
da4.addr = addr.addr.in.addr;
da = @ptrCast(*os.sockaddr, &da4);
dalen = @sizeOf(os.sockaddr_in);
sa = @ptrCast(*os.sockaddr, &sa4);
salen = @sizeOf(os.sockaddr_in);
}
const dpolicy = policyOf(da6.addr);
const dscope: i32 = scopeOf(da6.addr);
const dlabel = dpolicy.label;
const dprec: i32 = dpolicy.prec;
const MAXADDRS = 3;
var prefixlen: i32 = 0;
const sock_flags = os.SOCK_DGRAM | os.SOCK_CLOEXEC;
if (os.socket(addr.addr.any.family, sock_flags, os.IPPROTO_UDP)) |fd| syscalls: {
defer os.close(fd);
os.connect(fd, da, dalen) catch break :syscalls;
key |= DAS_USABLE;
os.getsockname(fd, sa, &salen) catch break :syscalls;
if (addr.addr.any.family == os.AF_INET) {
// TODO sa6.addr[12..16] should return *[4]u8, making this cast unnecessary.
mem.writeIntNative(u32, @ptrCast(*[4]u8, &sa6.addr[12]), sa4.addr);
}
if (dscope == @as(i32, scopeOf(sa6.addr))) key |= DAS_MATCHINGSCOPE;
if (dlabel == labelOf(sa6.addr)) key |= DAS_MATCHINGLABEL;
prefixlen = prefixMatch(sa6.addr, da6.addr);
} else |_| {}
key |= dprec << DAS_PREC_SHIFT;
key |= (15 - dscope) << DAS_SCOPE_SHIFT;
key |= prefixlen << DAS_PREFIX_SHIFT;
key |= (MAXADDRS - @intCast(i32, i)) << DAS_ORDER_SHIFT;
addr.sortkey = key;
}
std.sort.sort(LookupAddr, addrs.toSlice(), addrCmpLessThan);
}
const Policy = struct {
addr: [16]u8,
len: u8,
mask: u8,
prec: u8,
label: u8,
};
const defined_policies = [_]Policy{
Policy{
.addr = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01".*,
.len = 15,
.mask = 0xff,
.prec = 50,
.label = 0,
},
Policy{
.addr = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff\x00\x00\x00\x00".*,
.len = 11,
.mask = 0xff,
.prec = 35,
.label = 4,
},
Policy{
.addr = "\x20\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00".*,
.len = 1,
.mask = 0xff,
.prec = 30,
.label = 2,
},
Policy{
.addr = "\x20\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00".*,
.len = 3,
.mask = 0xff,
.prec = 5,
.label = 5,
},
Policy{
.addr = "\xfc\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00".*,
.len = 0,
.mask = 0xfe,
.prec = 3,
.label = 13,
},
// These are deprecated and/or returned to the address
// pool, so despite the RFC, treating them as special
// is probably wrong.
// { "", 11, 0xff, 1, 3 },
// { "\xfe\xc0", 1, 0xc0, 1, 11 },
// { "\x3f\xfe", 1, 0xff, 1, 12 },
// Last rule must match all addresses to stop loop.
Policy{
.addr = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00".*,
.len = 0,
.mask = 0,
.prec = 40,
.label = 1,
},
};
fn policyOf(a: [16]u8) *const Policy {
for (defined_policies) |*policy| {
if (!mem.eql(u8, a[0..policy.len], policy.addr[0..policy.len])) continue;
if ((a[policy.len] & policy.mask) != policy.addr[policy.len]) continue;
return policy;
}
unreachable;
}
fn scopeOf(a: [16]u8) u8 {
if (IN6_IS_ADDR_MULTICAST(a)) return a[1] & 15;
if (IN6_IS_ADDR_LINKLOCAL(a)) return 2;
if (IN6_IS_ADDR_LOOPBACK(a)) return 2;
if (IN6_IS_ADDR_SITELOCAL(a)) return 5;
return 14;
}
fn prefixMatch(s: [16]u8, d: [16]u8) u8 {
// TODO: This FIXME inherited from porting from musl libc.
// I don't want this to go into zig std lib 1.0.0.
// FIXME: The common prefix length should be limited to no greater
// than the nominal length of the prefix portion of the source
// address. However the definition of the source prefix length is
// not clear and thus this limiting is not yet implemented.
var i: u8 = 0;
while (i < 128 and ((s[i / 8] ^ d[i / 8]) & (@as(u8, 128) >> @intCast(u3, i % 8))) == 0) : (i += 1) {}
return i;
}
fn labelOf(a: [16]u8) u8 {
return policyOf(a).label;
}
fn IN6_IS_ADDR_MULTICAST(a: [16]u8) bool {
return a[0] == 0xff;
}
fn IN6_IS_ADDR_LINKLOCAL(a: [16]u8) bool {
return a[0] == 0xfe and (a[1] & 0xc0) == 0x80;
}
fn IN6_IS_ADDR_LOOPBACK(a: [16]u8) bool {
return a[0] == 0 and a[1] == 0 and
a[2] == 0 and
a[12] == 0 and a[13] == 0 and
a[14] == 0 and a[15] == 1;
}
fn IN6_IS_ADDR_SITELOCAL(a: [16]u8) bool {
return a[0] == 0xfe and (a[1] & 0xc0) == 0xc0;
}
// Parameters `b` and `a` swapped to make this descending.
fn addrCmpLessThan(b: LookupAddr, a: LookupAddr) bool {
return a.sortkey < b.sortkey;
}
fn linuxLookupNameFromNull(
addrs: *std.ArrayList(LookupAddr),
family: os.sa_family_t,
flags: u32,
port: u16,
) !void {
if ((flags & std.c.AI_PASSIVE) != 0) {
if (family != os.AF_INET6) {
(try addrs.addOne()).* = LookupAddr{
.addr = Address.initIp4([1]u8{0} ** 4, port),
};
}
if (family != os.AF_INET) {
(try addrs.addOne()).* = LookupAddr{
.addr = Address.initIp6([1]u8{0} ** 16, port, 0, 0),
};
}
} else {
if (family != os.AF_INET6) {
(try addrs.addOne()).* = LookupAddr{
.addr = Address.initIp4([4]u8{ 127, 0, 0, 1 }, port),
};
}
if (family != os.AF_INET) {
(try addrs.addOne()).* = LookupAddr{
.addr = Address.initIp6(([1]u8{0} ** 15) ++ [1]u8{1}, port, 0, 0),
};
}
}
}
fn linuxLookupNameFromHosts(
addrs: *std.ArrayList(LookupAddr),
canon: *std.Buffer,
name: []const u8,
family: os.sa_family_t,
port: u16,
) !void {
const file = fs.openFileAbsoluteC("/etc/hosts", .{}) catch |err| switch (err) {
error.FileNotFound,
error.NotDir,
error.AccessDenied,
=> return,
else => |e| return e,
};
defer file.close();
const stream = &std.io.BufferedInStream(fs.File.ReadError).init(&file.inStream().stream).stream;
var line_buf: [512]u8 = undefined;
while (stream.readUntilDelimiterOrEof(&line_buf, '\n') catch |err| switch (err) {
error.StreamTooLong => blk: {
// Skip to the delimiter in the stream, to fix parsing
try stream.skipUntilDelimiterOrEof('\n');
// Use the truncated line. A truncated comment or hostname will be handled correctly.
break :blk line_buf[0..];
},
else => |e| return e,
}) |line| {
const no_comment_line = mem.separate(line, "#").next().?;
var line_it = mem.tokenize(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 (first_name_text == null) first_name_text = name_text;
if (mem.eql(u8, name_text, name)) {
break;
}
} else continue;
const addr = Address.parseExpectingFamily(ip_text, family, port) catch |err| switch (err) {
error.Overflow,
error.InvalidEnd,
error.InvalidCharacter,
error.Incomplete,
error.InvalidIPAddressFormat,
error.InvalidIpv4Mapping,
=> continue,
};
try addrs.append(LookupAddr{ .addr = addr });
// first name is canonical name
const name_text = first_name_text.?;
if (isValidHostName(name_text)) {
try canon.replaceContents(name_text);
}
}
}
pub fn isValidHostName(hostname: []const u8) bool {
if (hostname.len >= 254) return false;
if (!std.unicode.utf8ValidateSlice(hostname)) return false;
for (hostname) |byte| {
if (byte >= 0x80 or byte == '.' or byte == '-' or std.ascii.isAlNum(byte)) {
continue;
}
return false;
}
return true;
}
fn linuxLookupNameFromDnsSearch(
addrs: *std.ArrayList(LookupAddr),
canon: *std.Buffer,
name: []const u8,
family: os.sa_family_t,
port: u16,
) !void {
var rc: ResolvConf = undefined;
try getResolvConf(addrs.allocator, &rc);
defer rc.deinit();
// Count dots, suppress search when >=ndots or name ends in
// a dot, which is an explicit request for global scope.
var dots: usize = 0;
for (name) |byte| {
if (byte == '.') dots += 1;
}
const search = if (rc.search.isNull() or dots >= rc.ndots or mem.endsWith(u8, name, "."))
&[_]u8{}
else
rc.search.toSliceConst();
var canon_name = name;
// Strip final dot for canon, fail if multiple trailing dots.
if (mem.endsWith(u8, canon_name, ".")) canon_name.len -= 1;
if (mem.endsWith(u8, canon_name, ".")) return error.UnknownHostName;
// Name with search domain appended is setup in canon[]. 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 name_from_dns.
try canon.resize(canon_name.len);
mem.copy(u8, canon.toSlice(), canon_name);
try canon.appendByte('.');
var tok_it = mem.tokenize(search, " \t");
while (tok_it.next()) |tok| {
canon.shrink(canon_name.len + 1);
try canon.append(tok);
try linuxLookupNameFromDns(addrs, canon, canon.toSliceConst(), family, rc, port);
if (addrs.len != 0) return;
}
canon.shrink(canon_name.len);
return linuxLookupNameFromDns(addrs, canon, name, family, rc, port);
}
const dpc_ctx = struct {
addrs: *std.ArrayList(LookupAddr),
canon: *std.Buffer,
port: u16,
};
fn linuxLookupNameFromDns(
addrs: *std.ArrayList(LookupAddr),
canon: *std.Buffer,
name: []const u8,
family: os.sa_family_t,
rc: ResolvConf,
port: u16,
) !void {
var ctx = dpc_ctx{
.addrs = addrs,
.canon = canon,
.port = port,
};
const AfRr = struct {
af: os.sa_family_t,
rr: u8,
};
const afrrs = [_]AfRr{
AfRr{ .af = os.AF_INET6, .rr = os.RR_A },
AfRr{ .af = os.AF_INET, .rr = os.RR_AAAA },
};
var qbuf: [2][280]u8 = undefined;
var abuf: [2][512]u8 = undefined;
var qp: [2][]const u8 = undefined;
const apbuf = [2][]u8{ &abuf[0], &abuf[1] };
var nq: usize = 0;
for (afrrs) |afrr| {
if (family != afrr.af) {
const len = os.res_mkquery(0, name, 1, afrr.rr, &[_]u8{}, null, &qbuf[nq]);
qp[nq] = qbuf[nq][0..len];
nq += 1;
}
}
var ap = [2][]u8{ apbuf[0][0..0], apbuf[1][0..0] };
try resMSendRc(qp[0..nq], ap[0..nq], apbuf[0..nq], rc);
var i: usize = 0;
while (i < nq) : (i += 1) {
dnsParse(ap[i], ctx, dnsParseCallback) catch {};
}
if (addrs.len != 0) return;
if (ap[0].len < 4 or (ap[0][3] & 15) == 2) return error.TemporaryNameServerFailure;
if ((ap[0][3] & 15) == 0) return error.UnknownHostName;
if ((ap[0][3] & 15) == 3) return;
return error.NameServerFailure;
}
const ResolvConf = struct {
attempts: u32,
ndots: u32,
timeout: u32,
search: std.Buffer,
ns: std.ArrayList(LookupAddr),
fn deinit(rc: *ResolvConf) void {
rc.ns.deinit();
rc.search.deinit();
rc.* = undefined;
}
};
/// Ignores lines longer than 512 bytes.
/// TODO: https://github.com/ziglang/zig/issues/2765 and https://github.com/ziglang/zig/issues/2761
fn getResolvConf(allocator: *mem.Allocator, rc: *ResolvConf) !void {
rc.* = ResolvConf{
.ns = std.ArrayList(LookupAddr).init(allocator),
.search = std.Buffer.initNull(allocator),
.ndots = 1,
.timeout = 5,
.attempts = 2,
};
errdefer rc.deinit();
const file = fs.openFileAbsoluteC("/etc/resolv.conf", .{}) catch |err| switch (err) {
error.FileNotFound,
error.NotDir,
error.AccessDenied,
=> return linuxLookupNameFromNumericUnspec(&rc.ns, "127.0.0.1", 53),
else => |e| return e,
};
defer file.close();
const stream = &std.io.BufferedInStream(fs.File.ReadError).init(&file.inStream().stream).stream;
var line_buf: [512]u8 = undefined;
while (stream.readUntilDelimiterOrEof(&line_buf, '\n') catch |err| switch (err) {
error.StreamTooLong => blk: {
// Skip to the delimiter in the stream, to fix parsing
try stream.skipUntilDelimiterOrEof('\n');
// Give an empty line to the while loop, which will be skipped.
break :blk line_buf[0..0];
},
else => |e| return e,
}) |line| {
const no_comment_line = mem.separate(line, "#").next().?;
var line_it = mem.tokenize(no_comment_line, " \t");
const token = line_it.next() orelse continue;
if (mem.eql(u8, token, "options")) {
while (line_it.next()) |sub_tok| {
var colon_it = mem.separate(sub_tok, ":");
const name = colon_it.next().?;
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,
};
if (mem.eql(u8, name, "ndots")) {
rc.ndots = std.math.min(value, 15);
} else if (mem.eql(u8, name, "attempts")) {
rc.attempts = std.math.min(value, 10);
} else if (mem.eql(u8, name, "timeout")) {
rc.timeout = std.math.min(value, 60);
}
}
} else if (mem.eql(u8, token, "nameserver")) {
const ip_txt = line_it.next() orelse continue;
try linuxLookupNameFromNumericUnspec(&rc.ns, ip_txt, 53);
} else if (mem.eql(u8, token, "domain") or mem.eql(u8, token, "search")) {
try rc.search.replaceContents(line_it.rest());
}
}
if (rc.ns.len == 0) {
return linuxLookupNameFromNumericUnspec(&rc.ns, "127.0.0.1", 53);
}
}
fn linuxLookupNameFromNumericUnspec(
addrs: *std.ArrayList(LookupAddr),
name: []const u8,
port: u16,
) !void {
const addr = try Address.parseIp(name, port);
(try addrs.addOne()).* = LookupAddr{ .addr = addr };
}
fn resMSendRc(
queries: []const []const u8,
answers: [][]u8,
answer_bufs: []const []u8,
rc: ResolvConf,
) !void {
const timeout = 1000 * rc.timeout;
const attempts = rc.attempts;
var sl: os.socklen_t = @sizeOf(os.sockaddr_in);
var family: os.sa_family_t = os.AF_INET;
var ns_list = std.ArrayList(Address).init(rc.ns.allocator);
defer ns_list.deinit();
try ns_list.resize(rc.ns.len);
const ns = ns_list.toSlice();
for (rc.ns.toSliceConst()) |iplit, i| {
ns[i] = iplit.addr;
assert(ns[i].getPort() == 53);
if (iplit.addr.any.family != os.AF_INET) {
sl = @sizeOf(os.sockaddr_in6);
family = os.AF_INET6;
}
}
// Get local address and open/bind a socket
var sa: Address = undefined;
@memset(@ptrCast([*]u8, &sa), 0, @sizeOf(Address));
sa.any.family = family;
const flags = os.SOCK_DGRAM | os.SOCK_CLOEXEC | os.SOCK_NONBLOCK;
const fd = os.socket(family, flags, 0) catch |err| switch (err) {
error.AddressFamilyNotSupported => blk: {
// Handle case where system lacks IPv6 support
if (family == os.AF_INET6) {
family = os.AF_INET;
break :blk try os.socket(os.AF_INET, flags, 0);
}
return err;
},
else => |e| return e,
};
defer os.close(fd);
try os.bind(fd, &sa.any, sl);
// Past this point, there are no errors. Each individual query will
// yield either no reply (indicated by zero length) or an answer
// packet which is up to the caller to interpret.
// Convert any IPv4 addresses in a mixed environment to v4-mapped
// TODO
//if (family == AF_INET6) {
// setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &(int){0}, sizeof 0);
// for (i=0; i<nns; i++) {
// if (ns[i].sin.sin_family != AF_INET) continue;
// memcpy(ns[i].sin6.sin6_addr.s6_addr+12,
// &ns[i].sin.sin_addr, 4);
// memcpy(ns[i].sin6.sin6_addr.s6_addr,
// "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
// ns[i].sin6.sin6_family = AF_INET6;
// ns[i].sin6.sin6_flowinfo = 0;
// ns[i].sin6.sin6_scope_id = 0;
// }
//}
var pfd = [1]os.pollfd{os.pollfd{
.fd = fd,
.events = os.POLLIN,
.revents = undefined,
}};
const retry_interval = timeout / attempts;
var next: u32 = 0;
var t2: u64 = std.time.milliTimestamp();
var t0 = t2;
var t1 = t2 - retry_interval;
var servfail_retry: usize = undefined;
outer: while (t2 - t0 < timeout) : (t2 = std.time.milliTimestamp()) {
if (t2 - t1 >= retry_interval) {
// Query all configured nameservers in parallel
var i: usize = 0;
while (i < queries.len) : (i += 1) {
if (answers[i].len == 0) {
var j: usize = 0;
while (j < ns.len) : (j += 1) {
_ = os.sendto(fd, queries[i], os.MSG_NOSIGNAL, &ns[j].any, sl) catch undefined;
}
}
}
t1 = t2;
servfail_retry = 2 * queries.len;
}
// Wait for a response, or until time to retry
const clamped_timeout = std.math.min(@as(u31, std.math.maxInt(u31)), t1 + retry_interval - t2);
const nevents = os.poll(&pfd, clamped_timeout) catch 0;
if (nevents == 0) continue;
while (true) {
var sl_copy = sl;
const rlen = os.recvfrom(fd, answer_bufs[next], 0, &sa.any, &sl_copy) catch break;
// Ignore non-identifiable packets
if (rlen < 4) continue;
// Ignore replies from addresses we didn't send to
var j: usize = 0;
while (j < ns.len and !ns[j].eql(sa)) : (j += 1) {}
if (j == ns.len) continue;
// Find which query this answer goes with, if any
var i: usize = next;
while (i < queries.len and (answer_bufs[next][0] != queries[i][0] or
answer_bufs[next][1] != queries[i][1])) : (i += 1)
{}
if (i == queries.len) continue;
if (answers[i].len != 0) continue;
// Only accept positive or negative responses;
// retry immediately on server failure, and ignore
// all other codes such as refusal.
switch (answer_bufs[next][3] & 15) {
0, 3 => {},
2 => if (servfail_retry != 0) {
servfail_retry -= 1;
_ = os.sendto(fd, queries[i], os.MSG_NOSIGNAL, &ns[j].any, sl) catch undefined;
},
else => continue,
}
// Store answer in the right slot, or update next
// available temp slot if it's already in place.
answers[i].len = rlen;
if (i == next) {
while (next < queries.len and answers[next].len != 0) : (next += 1) {}
} else {
mem.copy(u8, answer_bufs[i], answer_bufs[next][0..rlen]);
}
if (next == queries.len) break :outer;
}
}
}
fn dnsParse(
r: []const u8,
ctx: var,
comptime callback: var,
) !void {
// This implementation is ported from musl libc.
// A more idiomatic "ziggy" implementation would be welcome.
if (r.len < 12) return error.InvalidDnsPacket;
if ((r[3] & 15) != 0) return;
var p = r.ptr + 12;
var qdcount = r[4] * @as(usize, 256) + r[5];
var ancount = r[6] * @as(usize, 256) + r[7];
if (qdcount + ancount > 64) return error.InvalidDnsPacket;
while (qdcount != 0) {
qdcount -= 1;
while (@ptrToInt(p) - @ptrToInt(r.ptr) < r.len and p[0] -% 1 < 127) p += 1;
if (p[0] > 193 or (p[0] == 193 and p[1] > 254) or @ptrToInt(p) > @ptrToInt(r.ptr) + r.len - 6)
return error.InvalidDnsPacket;
p += @as(usize, 5) + @boolToInt(p[0] != 0);
}
while (ancount != 0) {
ancount -= 1;
while (@ptrToInt(p) - @ptrToInt(r.ptr) < r.len and p[0] -% 1 < 127) p += 1;
if (p[0] > 193 or (p[0] == 193 and p[1] > 254) or @ptrToInt(p) > @ptrToInt(r.ptr) + r.len - 6)
return error.InvalidDnsPacket;
p += @as(usize, 1) + @boolToInt(p[0] != 0);
const len = p[8] * @as(usize, 256) + p[9];
if (@ptrToInt(p) + len > @ptrToInt(r.ptr) + r.len) return error.InvalidDnsPacket;
try callback(ctx, p[1], p[10 .. 10 + len], r);
p += 10 + len;
}
}
fn dnsParseCallback(ctx: dpc_ctx, rr: u8, data: []const u8, packet: []const u8) !void {
switch (rr) {
os.RR_A => {
if (data.len != 4) return error.InvalidDnsARecord;
const new_addr = try ctx.addrs.addOne();
new_addr.* = LookupAddr{
// TODO slice [0..4] to make this *[4]u8 without @ptrCast
.addr = Address.initIp4(@ptrCast(*const [4]u8, data.ptr).*, ctx.port),
};
},
os.RR_AAAA => {
if (data.len != 16) return error.InvalidDnsAAAARecord;
const new_addr = try ctx.addrs.addOne();
new_addr.* = LookupAddr{
// TODO slice [0..16] to make this *[16]u8 without @ptrCast
.addr = Address.initIp6(@ptrCast(*const [16]u8, data.ptr).*, ctx.port, 0, 0),
};
},
os.RR_CNAME => {
var tmp: [256]u8 = undefined;
// Returns len of compressed name. strlen to get canon name.
_ = try os.dn_expand(packet, data, &tmp);
const canon_name = mem.toSliceConst(u8, @ptrCast([*:0]const u8, &tmp));
if (isValidHostName(canon_name)) {
try ctx.canon.replaceContents(canon_name);
}
},
else => return,
}
}
pub const StreamServer = struct {
/// Copied from `Options` on `init`.
kernel_backlog: u32,
/// `undefined` until `listen` returns successfully.
listen_address: Address,
sockfd: ?os.fd_t,
pub const Options = struct {
/// How many connections the kernel will accept on the application's behalf.
/// If more than this many connections pool in the kernel, clients will start
/// seeing "Connection refused".
kernel_backlog: u32 = 128,
};
/// After this call succeeds, resources have been acquired and must
/// be released with `deinit`.
pub fn init(options: Options) StreamServer {
return StreamServer{
.sockfd = null,
.kernel_backlog = options.kernel_backlog,
.listen_address = undefined,
};
}
/// Release all resources. The `StreamServer` memory becomes `undefined`.
pub fn deinit(self: *StreamServer) void {
self.close();
self.* = undefined;
}
pub fn listen(self: *StreamServer, address: Address) !void {
const nonblock = if (std.io.is_async) os.SOCK_NONBLOCK else 0;
const sock_flags = os.SOCK_STREAM | os.SOCK_CLOEXEC | nonblock;
const proto = if (address.any.family == os.AF_UNIX) @as(u32, 0) else os.IPPROTO_TCP;
const sockfd = try os.socket(address.any.family, sock_flags, proto);
self.sockfd = sockfd;
errdefer {
os.close(sockfd);
self.sockfd = null;
}
var socklen = address.getOsSockLen();
try os.bind(sockfd, &address.any, socklen);
try os.listen(sockfd, self.kernel_backlog);
try os.getsockname(sockfd, &self.listen_address.any, &socklen);
}
/// Stop listening. It is still necessary to call `deinit` after stopping listening.
/// Calling `deinit` will automatically call `close`. It is safe to call `close` when
/// not listening.
pub fn close(self: *StreamServer) void {
if (self.sockfd) |fd| {
os.close(fd);
self.sockfd = null;
self.listen_address = undefined;
}
}
pub const AcceptError = error{
ConnectionAborted,
/// The per-process limit on the number of open file descriptors has been reached.
ProcessFdQuotaExceeded,
/// The system-wide limit on the total number of open files has been reached.
SystemFdQuotaExceeded,
/// Not enough free memory. This often means that the memory allocation is limited
/// by the socket buffer limits, not by the system memory.
SystemResources,
ProtocolFailure,
/// Firewall rules forbid connection.
BlockedByFirewall,
} || os.UnexpectedError;
pub const Connection = struct {
file: fs.File,
address: Address,
};
/// If this function succeeds, the returned `Connection` is a caller-managed resource.
pub fn accept(self: *StreamServer) AcceptError!Connection {
const nonblock = if (std.io.is_async) os.SOCK_NONBLOCK else 0;
const accept_flags = nonblock | os.SOCK_CLOEXEC;
var accepted_addr: Address = undefined;
var adr_len: os.socklen_t = @sizeOf(Address);
if (os.accept4(self.sockfd.?, &accepted_addr.any, &adr_len, accept_flags)) |fd| {
return Connection{
.file = fs.File.openHandle(fd),
.address = accepted_addr,
};
} else |err| switch (err) {
// We only give SOCK_NONBLOCK when I/O mode is async, in which case this error
// is handled by os.accept4.
error.WouldBlock => unreachable,
else => |e| return e,
}
}
};
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