leo hendrickson / Mbed OS S

simple-mbed-cloud-client/mbed-cloud-client/nanostack-libservice/source/libip6string/stoip6.c@0:25fa8795676b, 2021-04-18 (annotated)

Committer:
leothedragon
Date:
Sun Apr 18 15:20:23 2021 +0000
Revision:
0:25fa8795676b
DS

Who changed what in which revision?

UserRevisionLine numberNew contents of line
leothedragon 0:25fa8795676b 1 /*
leothedragon 0:25fa8795676b 2 * Copyright (c) 2014-2015 ARM Limited. All rights reserved.
leothedragon 0:25fa8795676b 3 * SPDX-License-Identifier: Apache-2.0
leothedragon 0:25fa8795676b 4 * Licensed under the Apache License, Version 2.0 (the License); you may
leothedragon 0:25fa8795676b 5 * not use this file except in compliance with the License.
leothedragon 0:25fa8795676b 6 * You may obtain a copy of the License at
leothedragon 0:25fa8795676b 7 *
leothedragon 0:25fa8795676b 8 * http://www.apache.org/licenses/LICENSE-2.0
leothedragon 0:25fa8795676b 9 *
leothedragon 0:25fa8795676b 10 * Unless required by applicable law or agreed to in writing, software
leothedragon 0:25fa8795676b 11 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
leothedragon 0:25fa8795676b 12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
leothedragon 0:25fa8795676b 13 * See the License for the specific language governing permissions and
leothedragon 0:25fa8795676b 14 * limitations under the License.
leothedragon 0:25fa8795676b 15 */
leothedragon 0:25fa8795676b 16 #include <string.h>
leothedragon 0:25fa8795676b 17 #include <stdlib.h>
leothedragon 0:25fa8795676b 18 #include <stdint.h>
leothedragon 0:25fa8795676b 19 #include "common_functions.h"
leothedragon 0:25fa8795676b 20 #include "ip6string.h"
leothedragon 0:25fa8795676b 21
leothedragon 0:25fa8795676b 22 static uint16_t hex(const char *p);
leothedragon 0:25fa8795676b 23 static bool is_hex(char c);
leothedragon 0:25fa8795676b 24
leothedragon 0:25fa8795676b 25 /**
leothedragon 0:25fa8795676b 26 * Convert numeric IPv6 address string to a binary.
leothedragon 0:25fa8795676b 27 * IPv4 tunnelling addresses are not covered.
leothedragon 0:25fa8795676b 28 * \param ip6addr IPv6 address in string format.
leothedragon 0:25fa8795676b 29 * \param len Length of ipv6 string.
leothedragon 0:25fa8795676b 30 * \param dest buffer for address. MUST be 16 bytes.
leothedragon 0:25fa8795676b 31 * \return boolean set to true if conversion succeed, false if it didn't
leothedragon 0:25fa8795676b 32 */
leothedragon 0:25fa8795676b 33 bool stoip6(const char *ip6addr, size_t len, void *dest)
leothedragon 0:25fa8795676b 34 {
leothedragon 0:25fa8795676b 35 uint8_t *addr;
leothedragon 0:25fa8795676b 36 const char *p, *q;
leothedragon 0:25fa8795676b 37 int_fast8_t field_no, coloncolon = -1;
leothedragon 0:25fa8795676b 38
leothedragon 0:25fa8795676b 39 addr = dest;
leothedragon 0:25fa8795676b 40
leothedragon 0:25fa8795676b 41 if (len > 39) { // Too long, not possible. We do not support IPv4-mapped IPv6 addresses
leothedragon 0:25fa8795676b 42 goto error;
leothedragon 0:25fa8795676b 43 }
leothedragon 0:25fa8795676b 44
leothedragon 0:25fa8795676b 45 // First go forward the string, until end, noting :: position if any
leothedragon 0:25fa8795676b 46 // We're decrementing `len` as we go forward, and stop when it reaches 0
leothedragon 0:25fa8795676b 47 for (field_no = 0, p = ip6addr; len && *p; p = q + 1) {
leothedragon 0:25fa8795676b 48
leothedragon 0:25fa8795676b 49 for (q = p; len && *q && (*q != ':'); len -= 1) { // Seek for ':' or end
leothedragon 0:25fa8795676b 50 if (!is_hex(*q++)) { // There must only be hex characters besides ':'
leothedragon 0:25fa8795676b 51 goto error;
leothedragon 0:25fa8795676b 52 }
leothedragon 0:25fa8795676b 53 }
leothedragon 0:25fa8795676b 54
leothedragon 0:25fa8795676b 55 if ((q - p) > 4) { // We can't have more than 4 hex digits per segment
leothedragon 0:25fa8795676b 56 goto error;
leothedragon 0:25fa8795676b 57 }
leothedragon 0:25fa8795676b 58
leothedragon 0:25fa8795676b 59 if (field_no == 8) { // If the address goes farther than 8 segments
leothedragon 0:25fa8795676b 60 goto error;
leothedragon 0:25fa8795676b 61 }
leothedragon 0:25fa8795676b 62
leothedragon 0:25fa8795676b 63 // Convert and write this part, (high-endian AKA network byte order)
leothedragon 0:25fa8795676b 64 addr = common_write_16_bit(hex(p), addr);
leothedragon 0:25fa8795676b 65 field_no++;
leothedragon 0:25fa8795676b 66
leothedragon 0:25fa8795676b 67 // We handle the colons
leothedragon 0:25fa8795676b 68 if (len) {
leothedragon 0:25fa8795676b 69 // Check if we reached "::"
leothedragon 0:25fa8795676b 70 if (q[0] == ':' && q[1] == ':') {
leothedragon 0:25fa8795676b 71 if (coloncolon != -1) { // We are not supposed to see "::" more than once per address
leothedragon 0:25fa8795676b 72 goto error;
leothedragon 0:25fa8795676b 73 }
leothedragon 0:25fa8795676b 74 coloncolon = field_no;
leothedragon 0:25fa8795676b 75 q++;
leothedragon 0:25fa8795676b 76 len -= 2;
leothedragon 0:25fa8795676b 77 } else {
leothedragon 0:25fa8795676b 78 len -= 1;
leothedragon 0:25fa8795676b 79 }
leothedragon 0:25fa8795676b 80 }
leothedragon 0:25fa8795676b 81 }
leothedragon 0:25fa8795676b 82
leothedragon 0:25fa8795676b 83 if (coloncolon != -1) {
leothedragon 0:25fa8795676b 84 /* Insert zeros in the appropriate place */
leothedragon 0:25fa8795676b 85 uint_fast8_t head_size = 2 * coloncolon;
leothedragon 0:25fa8795676b 86 uint_fast8_t inserted_size = 2 * (8 - field_no);
leothedragon 0:25fa8795676b 87 uint_fast8_t tail_size = 16 - head_size - inserted_size;
leothedragon 0:25fa8795676b 88 addr = dest;
leothedragon 0:25fa8795676b 89 memmove(addr + head_size + inserted_size, addr + head_size, tail_size);
leothedragon 0:25fa8795676b 90 memset(addr + head_size, 0, inserted_size);
leothedragon 0:25fa8795676b 91 } else if (field_no != 8) { // Report an error if we didn't get 8 fields
leothedragon 0:25fa8795676b 92 goto error;
leothedragon 0:25fa8795676b 93 }
leothedragon 0:25fa8795676b 94 return true;
leothedragon 0:25fa8795676b 95
leothedragon 0:25fa8795676b 96 error:
leothedragon 0:25fa8795676b 97 // Fill the output buffer with 0 so we stick to the old failure behavior.
leothedragon 0:25fa8795676b 98 // We are however more agressive and wipe the entire address, and do so more often.
leothedragon 0:25fa8795676b 99 memset(dest, 0, 16);
leothedragon 0:25fa8795676b 100 return false;
leothedragon 0:25fa8795676b 101 }
leothedragon 0:25fa8795676b 102
leothedragon 0:25fa8795676b 103 unsigned char sipv6_prefixlength(const char *ip6addr)
leothedragon 0:25fa8795676b 104 {
leothedragon 0:25fa8795676b 105 char *ptr = strchr(ip6addr, '/');
leothedragon 0:25fa8795676b 106 if (ptr) {
leothedragon 0:25fa8795676b 107 return (unsigned char)strtoul(ptr + 1, 0, 10);
leothedragon 0:25fa8795676b 108 }
leothedragon 0:25fa8795676b 109 return 0;
leothedragon 0:25fa8795676b 110 }
leothedragon 0:25fa8795676b 111
leothedragon 0:25fa8795676b 112 int stoip6_prefix(const char *ip6addr, void *dest, int_fast16_t *prefix_len_out)
leothedragon 0:25fa8795676b 113 {
leothedragon 0:25fa8795676b 114 size_t addr_len, total_len;
leothedragon 0:25fa8795676b 115 int_fast16_t prefix_length;
leothedragon 0:25fa8795676b 116
leothedragon 0:25fa8795676b 117 if (prefix_len_out) {
leothedragon 0:25fa8795676b 118 *prefix_len_out = -1;
leothedragon 0:25fa8795676b 119 }
leothedragon 0:25fa8795676b 120
leothedragon 0:25fa8795676b 121 total_len = addr_len = strlen(ip6addr);
leothedragon 0:25fa8795676b 122 const char *ptr = strchr(ip6addr, '/');
leothedragon 0:25fa8795676b 123 if (ptr) {
leothedragon 0:25fa8795676b 124 addr_len = ptr - ip6addr;
leothedragon 0:25fa8795676b 125 if (prefix_len_out) {
leothedragon 0:25fa8795676b 126 if (total_len - addr_len > 3) {
leothedragon 0:25fa8795676b 127 /* too many digits in prefix */
leothedragon 0:25fa8795676b 128 return -1;
leothedragon 0:25fa8795676b 129 }
leothedragon 0:25fa8795676b 130
leothedragon 0:25fa8795676b 131 prefix_length = strtoul(ptr + 1, 0, 10);
leothedragon 0:25fa8795676b 132 if (prefix_length < 0 || prefix_length > 128) {
leothedragon 0:25fa8795676b 133 /* prefix value illegal */
leothedragon 0:25fa8795676b 134 return -1;
leothedragon 0:25fa8795676b 135 }
leothedragon 0:25fa8795676b 136
leothedragon 0:25fa8795676b 137 *prefix_len_out = prefix_length;
leothedragon 0:25fa8795676b 138 }
leothedragon 0:25fa8795676b 139 }
leothedragon 0:25fa8795676b 140
leothedragon 0:25fa8795676b 141 if (!stoip6(ip6addr, addr_len, dest)) {
leothedragon 0:25fa8795676b 142 /* parser failure */
leothedragon 0:25fa8795676b 143 return -1;
leothedragon 0:25fa8795676b 144 }
leothedragon 0:25fa8795676b 145
leothedragon 0:25fa8795676b 146 return 0;
leothedragon 0:25fa8795676b 147 }
leothedragon 0:25fa8795676b 148
leothedragon 0:25fa8795676b 149 static bool is_hex(char c)
leothedragon 0:25fa8795676b 150 {
leothedragon 0:25fa8795676b 151 // 'A' (0x41) and 'a' (0x61) are mapped in the ASCII table in such a way that masking the 0x20 bit turn 'a' in 'A'
leothedragon 0:25fa8795676b 152 if ((c & ~0x20) >= 'A' && (c & ~0x20) <= 'F') {
leothedragon 0:25fa8795676b 153 return true;
leothedragon 0:25fa8795676b 154 }
leothedragon 0:25fa8795676b 155
leothedragon 0:25fa8795676b 156 if (c >= '0' && c <= '9') {
leothedragon 0:25fa8795676b 157 return true;
leothedragon 0:25fa8795676b 158 }
leothedragon 0:25fa8795676b 159
leothedragon 0:25fa8795676b 160 return false;
leothedragon 0:25fa8795676b 161 }
leothedragon 0:25fa8795676b 162
leothedragon 0:25fa8795676b 163 static uint16_t hex(const char *p)
leothedragon 0:25fa8795676b 164 {
leothedragon 0:25fa8795676b 165 uint16_t val = 0;
leothedragon 0:25fa8795676b 166
leothedragon 0:25fa8795676b 167 for (;;) {
leothedragon 0:25fa8795676b 168 char c = *p++;
leothedragon 0:25fa8795676b 169 if ((c >= '0') && (c <= '9')) {
leothedragon 0:25fa8795676b 170 val = (val << 4) | (c - '0');
leothedragon 0:25fa8795676b 171 } else if ((c >= 'A') && (c <= 'F')) {
leothedragon 0:25fa8795676b 172 val = (val << 4) | (10 + (c - 'A'));
leothedragon 0:25fa8795676b 173 } else if ((c >= 'a') && (c <= 'f')) {
leothedragon 0:25fa8795676b 174 val = (val << 4) | (10 + (c - 'a'));
leothedragon 0:25fa8795676b 175 } else {
leothedragon 0:25fa8795676b 176 break; // Non hex character
leothedragon 0:25fa8795676b 177 }
leothedragon 0:25fa8795676b 178 }
leothedragon 0:25fa8795676b 179 return val;
leothedragon 0:25fa8795676b 180 }