b64_ntop.c revision 238104
1238104Sdes/* 2238104Sdes * Copyright (c) 1996, 1998 by Internet Software Consortium. 3238104Sdes * 4238104Sdes * Permission to use, copy, modify, and distribute this software for any 5238104Sdes * purpose with or without fee is hereby granted, provided that the above 6238104Sdes * copyright notice and this permission notice appear in all copies. 7238104Sdes * 8238104Sdes * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS 9238104Sdes * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES 10238104Sdes * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE 11238104Sdes * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 12238104Sdes * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 13238104Sdes * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 14238104Sdes * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 15238104Sdes * SOFTWARE. 16238104Sdes */ 17238104Sdes 18238104Sdes/* 19238104Sdes * Portions Copyright (c) 1995 by International Business Machines, Inc. 20238104Sdes * 21238104Sdes * International Business Machines, Inc. (hereinafter called IBM) grants 22238104Sdes * permission under its copyrights to use, copy, modify, and distribute this 23238104Sdes * Software with or without fee, provided that the above copyright notice and 24238104Sdes * all paragraphs of this notice appear in all copies, and that the name of IBM 25238104Sdes * not be used in connection with the marketing of any product incorporating 26238104Sdes * the Software or modifications thereof, without specific, written prior 27238104Sdes * permission. 28238104Sdes * 29238104Sdes * To the extent it has a right to do so, IBM grants an immunity from suit 30238104Sdes * under its patents, if any, for the use, sale or manufacture of products to 31238104Sdes * the extent that such products are used for performing Domain Name System 32238104Sdes * dynamic updates in TCP/IP networks by means of the Software. No immunity is 33238104Sdes * granted for any product per se or for any other function of any product. 34238104Sdes * 35238104Sdes * THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES, 36238104Sdes * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 37238104Sdes * PARTICULAR PURPOSE. IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL, 38238104Sdes * DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING 39238104Sdes * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN 40238104Sdes * IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES. 41238104Sdes */ 42238104Sdes#include <ldns/config.h> 43238104Sdes 44238104Sdes#include <sys/types.h> 45238104Sdes#include <sys/param.h> 46238104Sdes#ifdef HAVE_SYS_SOCKET_H 47238104Sdes#include <sys/socket.h> 48238104Sdes#endif 49238104Sdes 50238104Sdes#ifdef HAVE_NETINET_IN_H 51238104Sdes#include <netinet/in.h> 52238104Sdes#endif 53238104Sdes#ifdef HAVE_ARPA_INET_H 54238104Sdes#include <arpa/inet.h> 55238104Sdes#endif 56238104Sdes 57238104Sdes#include <ctype.h> 58238104Sdes#include <stdio.h> 59238104Sdes#include <stdlib.h> 60238104Sdes#include <string.h> 61238104Sdes 62238104Sdes#define Assert(Cond) if (!(Cond)) abort() 63238104Sdes 64238104Sdesstatic const char Base64[] = 65238104Sdes "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 66238104Sdesstatic const char Pad64 = '='; 67238104Sdes 68238104Sdes/* (From RFC1521 and draft-ietf-dnssec-secext-03.txt) 69238104Sdes The following encoding technique is taken from RFC 1521 by Borenstein 70238104Sdes and Freed. It is reproduced here in a slightly edited form for 71238104Sdes convenience. 72238104Sdes 73238104Sdes A 65-character subset of US-ASCII is used, enabling 6 bits to be 74238104Sdes represented per printable character. (The extra 65th character, "=", 75238104Sdes is used to signify a special processing function.) 76238104Sdes 77238104Sdes The encoding process represents 24-bit groups of input bits as output 78238104Sdes strings of 4 encoded characters. Proceeding from left to right, a 79238104Sdes 24-bit input group is formed by concatenating 3 8-bit input groups. 80238104Sdes These 24 bits are then treated as 4 concatenated 6-bit groups, each 81238104Sdes of which is translated into a single digit in the base64 alphabet. 82238104Sdes 83238104Sdes Each 6-bit group is used as an index into an array of 64 printable 84238104Sdes characters. The character referenced by the index is placed in the 85238104Sdes output string. 86238104Sdes 87238104Sdes Table 1: The Base64 Alphabet 88238104Sdes 89238104Sdes Value Encoding Value Encoding Value Encoding Value Encoding 90238104Sdes 0 A 17 R 34 i 51 z 91238104Sdes 1 B 18 S 35 j 52 0 92238104Sdes 2 C 19 T 36 k 53 1 93238104Sdes 3 D 20 U 37 l 54 2 94238104Sdes 4 E 21 V 38 m 55 3 95238104Sdes 5 F 22 W 39 n 56 4 96238104Sdes 6 G 23 X 40 o 57 5 97238104Sdes 7 H 24 Y 41 p 58 6 98238104Sdes 8 I 25 Z 42 q 59 7 99238104Sdes 9 J 26 a 43 r 60 8 100238104Sdes 10 K 27 b 44 s 61 9 101238104Sdes 11 L 28 c 45 t 62 + 102238104Sdes 12 M 29 d 46 u 63 / 103238104Sdes 13 N 30 e 47 v 104238104Sdes 14 O 31 f 48 w (pad) = 105238104Sdes 15 P 32 g 49 x 106238104Sdes 16 Q 33 h 50 y 107238104Sdes 108238104Sdes Special processing is performed if fewer than 24 bits are available 109238104Sdes at the end of the data being encoded. A full encoding quantum is 110238104Sdes always completed at the end of a quantity. When fewer than 24 input 111238104Sdes bits are available in an input group, zero bits are added (on the 112238104Sdes right) to form an integral number of 6-bit groups. Padding at the 113238104Sdes end of the data is performed using the '=' character. 114238104Sdes 115238104Sdes Since all base64 input is an integral number of octets, only the 116238104Sdes ------------------------------------------------- 117238104Sdes following cases can arise: 118238104Sdes 119238104Sdes (1) the final quantum of encoding input is an integral 120238104Sdes multiple of 24 bits; here, the final unit of encoded 121238104Sdes output will be an integral multiple of 4 characters 122238104Sdes with no "=" padding, 123238104Sdes (2) the final quantum of encoding input is exactly 8 bits; 124238104Sdes here, the final unit of encoded output will be two 125238104Sdes characters followed by two "=" padding characters, or 126238104Sdes (3) the final quantum of encoding input is exactly 16 bits; 127238104Sdes here, the final unit of encoded output will be three 128238104Sdes characters followed by one "=" padding character. 129238104Sdes */ 130238104Sdes 131238104Sdesint 132238104Sdesldns_b64_ntop(uint8_t const *src, size_t srclength, char *target, size_t targsize) { 133238104Sdes size_t datalength = 0; 134238104Sdes uint8_t input[3]; 135238104Sdes uint8_t output[4]; 136238104Sdes size_t i; 137238104Sdes 138238104Sdes if (srclength == 0) { 139238104Sdes if (targsize > 0) { 140238104Sdes target[0] = '\0'; 141238104Sdes return 0; 142238104Sdes } else { 143238104Sdes return -1; 144238104Sdes } 145238104Sdes } 146238104Sdes 147238104Sdes while (2 < srclength) { 148238104Sdes input[0] = *src++; 149238104Sdes input[1] = *src++; 150238104Sdes input[2] = *src++; 151238104Sdes srclength -= 3; 152238104Sdes 153238104Sdes output[0] = input[0] >> 2; 154238104Sdes output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 155238104Sdes output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 156238104Sdes output[3] = input[2] & 0x3f; 157238104Sdes Assert(output[0] < 64); 158238104Sdes Assert(output[1] < 64); 159238104Sdes Assert(output[2] < 64); 160238104Sdes Assert(output[3] < 64); 161238104Sdes 162238104Sdes if (datalength + 4 > targsize) { 163238104Sdes return (-1); 164238104Sdes } 165238104Sdes target[datalength++] = Base64[output[0]]; 166238104Sdes target[datalength++] = Base64[output[1]]; 167238104Sdes target[datalength++] = Base64[output[2]]; 168238104Sdes target[datalength++] = Base64[output[3]]; 169238104Sdes } 170238104Sdes 171238104Sdes /* Now we worry about padding. */ 172238104Sdes if (0 != srclength) { 173238104Sdes /* Get what's left. */ 174238104Sdes input[0] = input[1] = input[2] = (uint8_t) '\0'; 175238104Sdes for (i = 0; i < srclength; i++) 176238104Sdes input[i] = *src++; 177238104Sdes 178238104Sdes output[0] = input[0] >> 2; 179238104Sdes output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); 180238104Sdes output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); 181238104Sdes Assert(output[0] < 64); 182238104Sdes Assert(output[1] < 64); 183238104Sdes Assert(output[2] < 64); 184238104Sdes 185238104Sdes if (datalength + 4 > targsize) { 186238104Sdes return (-2); 187238104Sdes } 188238104Sdes target[datalength++] = Base64[output[0]]; 189238104Sdes target[datalength++] = Base64[output[1]]; 190238104Sdes if (srclength == 1) { 191238104Sdes target[datalength++] = Pad64; 192238104Sdes } else { 193238104Sdes target[datalength++] = Base64[output[2]]; 194238104Sdes } 195238104Sdes target[datalength++] = Pad64; 196238104Sdes } 197238104Sdes if (datalength >= targsize) { 198238104Sdes return (-3); 199238104Sdes } 200238104Sdes target[datalength] = '\0'; /* Returned value doesn't count \0. */ 201238104Sdes return (int) (datalength); 202238104Sdes} 203