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Support IPv6 shorthand and IPv4-mapped addresses in inet_{pton,ntop}(3).

This commit is contained in:
Jonas 'Sortie' Termansen 2020-07-26 00:06:09 +02:00
parent 8d4b932f0f
commit 185a9fa221
2 changed files with 103 additions and 17 deletions
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59
libc/arpa/inet/inet_ntop.c
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2016 Jonas 'Sortie' Termansen.
* Copyright (c) 2016, 2020 Jonas 'Sortie' Termansen.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
@ -21,8 +21,8 @@
#include <errno.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdio.h>
#include <string.h>
const char* inet_ntop(int af,
const void* restrict src,
@ -42,18 +42,53 @@ const char* inet_ntop(int af,
}
else if ( af == AF_INET6 )
{
// TODO: Support for :: syntax.
// TODO: Support for x:x:x:x:x:x:d.d.d.d syntax.
// TODO: When should x:x:x:x:x:x:d.d.d.d notation be used?
const unsigned char* ip = (const unsigned char*) src;
int len = snprintf(dst, size, "%x:%x:%x:%x:%x:%x:%x:%x",
ip[0] << 8 | ip[1], ip[2] << 8 | ip[3],
ip[4] << 8 | ip[5], ip[6] << 8 | ip[7],
ip[8] << 8 | ip[9], ip[10] << 8 | ip[11],
ip[12] << 8 | ip[13], ip[14] << 8 | ip[15]);
if ( len < 0 )
return NULL;
if ( size <= (size_t) len )
size_t longest_zeroes_offset = 0;
size_t longest_zeroes_length = 0;
size_t current_zeroes_offset = 0;
size_t current_zeroes_length = 0;
for ( size_t i = 0; i < 8; i++ )
{
const unsigned char* data = ip + i * 2;
if ( !data[0] && !data[1] )
{
current_zeroes_length++;
if ( longest_zeroes_length < current_zeroes_length )
{
longest_zeroes_offset = current_zeroes_offset;
longest_zeroes_length = current_zeroes_length;
}
}
else
{
current_zeroes_offset = i + 1;
current_zeroes_length = 0;
}
}
char buffer[INET6_ADDRSTRLEN];
size_t offset = 0;
for ( size_t i = 0; i < 8; i++ )
{
const unsigned char* data = ip + i * 2;
if ( i == longest_zeroes_offset && 2 <= longest_zeroes_length )
{
buffer[offset++] = ':';
buffer[offset++] = ':';
i += longest_zeroes_length - 1;
}
else
{
if ( offset && buffer[offset - 1] != ':' )
buffer[offset++] = ':';
offset += snprintf(buffer + offset, sizeof(buffer) - offset,
"%x", data[0] << 8 | data[1]);
}
}
buffer[offset] = '\0';
if ( size <= (size_t) offset )
return errno = ENOSPC, (const char*) NULL;
memcpy(dst, buffer, offset + 1);
return dst;
}
else

61
libc/arpa/inet/inet_pton.c
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2016 Jonas 'Sortie' Termansen.
* Copyright (c) 2016, 2020 Jonas 'Sortie' Termansen.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
@ -61,15 +61,55 @@ int inet_pton(int af, const char* restrict src, void* restrict dst)
{
unsigned char ip[16];
size_t index = 0;
// TODO: Support for :: syntax.
// TODO: Support for x:x:x:x:x:x:d.d.d.d syntax.
for ( int i = 0; i < 8; i++ )
int compressed_at = -1;
int i;
for ( i = 0; i < 8; i++ )
{
if ( i && src[index++] != ':' )
if ( compressed_at == -1 &&
src[index + 0] == ':' &&
src[index + 1] == ':' )
{
index += 2;
compressed_at = i;
}
else if ( !src[index] )
break;
else if ( i && src[index++] != ':' )
return 0;
int num = 0;
for ( int j = 0; j < 4; j++ )
{
if ( src[index] == '.' &&
((compressed_at == -1 && i == 6) ||
(0 < compressed_at && i <= 6)) )
{
index -= j;
for ( int n = 0; n < 4; n++ )
{
if ( n && src[index++] != '.' )
return 0;
num = 0;
for ( int m = 0; m < 3; m++ )
{
if ( !m && src[index] == '0' )
{
index++;
break;
}
if ( '0' <= src[index] && src[index] <= '9' )
num = num * 10 + src[index++] - '0';
else if ( !m )
return 0;
else
break;
}
if ( 255 < num )
return 0;
ip[2 * i + n] = num;
}
i += 2;
goto done;
}
int dgt;
if ( '0' <= src[index] && src[index] <= '9' )
dgt = src[index] - '0';
@ -89,8 +129,19 @@ int inet_pton(int af, const char* restrict src, void* restrict dst)
ip[2 * i + 0] = num >> 8 & 0xFF;
ip[2 * i + 1] = num >> 0 & 0xFF;
}
done:
if ( src[index] )
return 0;
if ( 0 <= compressed_at )
{
if ( i == 8 )
return 0;
memmove(ip + 16 - 2 * (i - compressed_at), ip + 2 * compressed_at,
(i - compressed_at) * 2);
memset(ip + 2 * compressed_at, 0, (8 - i) * 2);
}
else if ( i < 8 )
return 0;
memcpy(dst, ip, sizeof(ip));
return 1;
}