97 lines
2.8 KiB
C
97 lines
2.8 KiB
C
/*
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* Copyright (c) 2016, 2020 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* arpa/inet/inet_ntop.c
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* Convert network address to string.
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*/
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#include <sys/socket.h>
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#include <errno.h>
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#include <arpa/inet.h>
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#include <stdio.h>
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#include <string.h>
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const char* inet_ntop(int af,
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const void* restrict src,
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char* restrict dst,
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socklen_t size)
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{
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if ( af == AF_INET )
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{
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const unsigned char* ip = (const unsigned char*) src;
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int len = snprintf(dst, size, "%u.%u.%u.%u",
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ip[0], ip[1], ip[2], ip[3]);
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if ( len < 0 )
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return NULL;
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if ( size <= (size_t) len )
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return errno = ENOSPC, (const char*) NULL;
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return dst;
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}
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else if ( af == AF_INET6 )
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{
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// TODO: When should x:x:x:x:x:x:d.d.d.d notation be used?
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const unsigned char* ip = (const unsigned char*) src;
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size_t longest_zeroes_offset = 0;
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size_t longest_zeroes_length = 0;
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size_t current_zeroes_offset = 0;
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size_t current_zeroes_length = 0;
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for ( size_t i = 0; i < 8; i++ )
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{
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const unsigned char* data = ip + i * 2;
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if ( !data[0] && !data[1] )
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{
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current_zeroes_length++;
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if ( longest_zeroes_length < current_zeroes_length )
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{
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longest_zeroes_offset = current_zeroes_offset;
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longest_zeroes_length = current_zeroes_length;
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}
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}
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else
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{
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current_zeroes_offset = i + 1;
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current_zeroes_length = 0;
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}
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}
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char buffer[INET6_ADDRSTRLEN];
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size_t offset = 0;
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for ( size_t i = 0; i < 8; i++ )
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{
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const unsigned char* data = ip + i * 2;
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if ( i == longest_zeroes_offset && 2 <= longest_zeroes_length )
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{
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buffer[offset++] = ':';
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buffer[offset++] = ':';
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i += longest_zeroes_length - 1;
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}
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else
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{
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if ( offset && buffer[offset - 1] != ':' )
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buffer[offset++] = ':';
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offset += snprintf(buffer + offset, sizeof(buffer) - offset,
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"%x", data[0] << 8 | data[1]);
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}
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}
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buffer[offset] = '\0';
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if ( size <= (size_t) offset )
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return errno = ENOSPC, (const char*) NULL;
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memcpy(dst, buffer, offset + 1);
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return dst;
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}
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else
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return errno = EAFNOSUPPORT, NULL;
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}
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