authorgravatar for anders@bondehagen.comAnders Bondehagen <anders@bondehagen.com> 2025-02-23 04:52:47+01:00
committergravatar for noreply@github.comGitHub <noreply@github.com> 2025-02-22 19:52:47-08:00
log77007445bf94f59b88db0ec6a9f0e76edafe2b74
tree5d3c0b8b6c657b16f00bbc0bc0a5937cf4381248
parent220f80e71dbcb9dac4ed71845573a95b75299e4c
signaturebadge-check Signed by PGP key B5690EEEBB952194

std.net: Fix IPv6 address format compression for long zero runs (#22441)

2 files changed, 90 insertions(+), 1 deletions(-)

lib/std/net.zig+34-1
...@@ -683,17 +683,50 @@ pub const Ip6Address = extern struct {...@@ -683,17 +683,50 @@ pub const Ip6Address = extern struct {
683 break :blk buf;683 break :blk buf;
684 },684 },
685 };685 };
686
687 // Find the longest zero run
688 var longest_start: usize = 8;
689 var longest_len: usize = 0;
690 var current_start: usize = 0;
691 var current_len: usize = 0;
692
693 for (native_endian_parts, 0..) |part, i| {
694 if (part == 0) {
695 if (current_len == 0) {
696 current_start = i;
697 }
698 current_len += 1;
699 if (current_len > longest_len) {
700 longest_start = current_start;
701 longest_len = current_len;
702 }
703 } else {
704 current_len = 0;
705 }
706 }
707
708 // Only compress if the longest zero run is 2 or more
709 if (longest_len < 2) {
710 longest_start = 8;
711 longest_len = 0;
712 }
713
686 try out_stream.writeAll("[");714 try out_stream.writeAll("[");
687 var i: usize = 0;715 var i: usize = 0;
688 var abbrv = false;716 var abbrv = false;
689 while (i < native_endian_parts.len) : (i += 1) {717 while (i < native_endian_parts.len) : (i += 1) {
690 if (native_endian_parts[i] == 0) {718 if (i == longest_start) {
719 // Emit "::" for the longest zero run
691 if (!abbrv) {720 if (!abbrv) {
692 try out_stream.writeAll(if (i == 0) "::" else ":");721 try out_stream.writeAll(if (i == 0) "::" else ":");
693 abbrv = true;722 abbrv = true;
694 }723 }
724 i += longest_len - 1; // Skip the compressed range
695 continue;725 continue;
696 }726 }
727 if (abbrv) {
728 abbrv = false;
729 }
697 try std.fmt.format(out_stream, "{x}", .{native_endian_parts[i]});730 try std.fmt.format(out_stream, "{x}", .{native_endian_parts[i]});
698 if (i != native_endian_parts.len - 1) {731 if (i != native_endian_parts.len - 1) {
699 try out_stream.writeAll(":");732 try out_stream.writeAll(":");
lib/std/net/test.zig+56
...@@ -26,6 +26,62 @@ test "parse and render IP addresses at comptime" {...@@ -26,6 +26,62 @@ test "parse and render IP addresses at comptime" {
26 }26 }
27}27}
2828
29test "format IPv6 address with no zero runs" {
30 if (builtin.os.tag == .wasi) return error.SkipZigTest;
31
32 const addr = try std.net.Address.parseIp6("2001:db8:1:2:3:4:5:6", 0);
33
34 var buffer: [50]u8 = undefined;
35 const result = std.fmt.bufPrint(buffer[0..], "{}", .{addr}) catch unreachable;
36
37 try std.testing.expectEqualStrings("[2001:db8:1:2:3:4:5:6]:0", result);
38}
39
40test "parse IPv6 addresses and check compressed form" {
41 if (builtin.os.tag == .wasi) return error.SkipZigTest;
42
43 const alloc = testing.allocator;
44
45 // 1) Parse an IPv6 address that should compress to [2001:db8::1:0:0:2]:0
46 const addr1 = try std.net.Address.parseIp6("2001:0db8:0000:0000:0001:0000:0000:0002", 0);
47
48 // 2) Parse an IPv6 address that should compress to [2001:db8::1:2]:0
49 const addr2 = try std.net.Address.parseIp6("2001:0db8:0000:0000:0000:0000:0001:0002", 0);
50
51 // 3) Parse an IPv6 address that should compress to [2001:db8:1:0:1::2]:0
52 const addr3 = try std.net.Address.parseIp6("2001:0db8:0001:0000:0001:0000:0000:0002", 0);
53
54 // Print each address in Zig's default "[ipv6]:port" form.
55 const printed1 = try std.fmt.allocPrint(alloc, "{any}", .{addr1});
56 defer testing.allocator.free(printed1);
57 const printed2 = try std.fmt.allocPrint(alloc, "{any}", .{addr2});
58 defer testing.allocator.free(printed2);
59 const printed3 = try std.fmt.allocPrint(alloc, "{any}", .{addr3});
60 defer testing.allocator.free(printed3);
61
62 // Check the exact compressed forms we expect.
63 try std.testing.expectEqualStrings("[2001:db8::1:0:0:2]:0", printed1);
64 try std.testing.expectEqualStrings("[2001:db8::1:2]:0", printed2);
65 try std.testing.expectEqualStrings("[2001:db8:1:0:1::2]:0", printed3);
66}
67
68test "parse IPv6 address, check raw bytes" {
69 if (builtin.os.tag == .wasi) return error.SkipZigTest;
70
71 const expected_raw: [16]u8 = .{
72 0x20, 0x01, 0x0d, 0xb8, // 2001:db8
73 0x00, 0x00, 0x00, 0x00, // :0000:0000
74 0x00, 0x01, 0x00, 0x00, // :0001:0000
75 0x00, 0x00, 0x00, 0x02, // :0000:0002
76 };
77
78 const addr = try std.net.Address.parseIp6("2001:db8:0000:0000:0001:0000:0000:0002", 0);
79
80 const actual_raw = addr.in6.sa.addr[0..];
81 try std.testing.expectEqualSlices(u8, expected_raw[0..], actual_raw);
82
83}
84
29test "parse and render IPv6 addresses" {85test "parse and render IPv6 addresses" {
30 if (builtin.os.tag == .wasi) return error.SkipZigTest;86 if (builtin.os.tag == .wasi) return error.SkipZigTest;
3187