stoip6.c

00001 /*
00002  * Copyright (c) 2014-2015 ARM Limited. All rights reserved.
00003  * SPDX-License-Identifier: Apache-2.0
00004  * Licensed under the Apache License, Version 2.0 (the License); you may
00005  * not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  * http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an AS IS BASIS, WITHOUT
00012  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 #include <string.h>
00017 #include <stdlib.h>
00018 #include <stdint.h>
00019 #include "common_functions.h"
00020 #include "ip6string.h"
00021 
00022 static uint16_t hex(const char *p);
00023 
00024 /**
00025  * Convert numeric IPv6 address string to a binary.
00026  * IPv4 tunnelling addresses are not covered.
00027  * \param ip6addr IPv6 address in string format.
00028  * \param len Length of ipv6 string.
00029  * \param dest buffer for address. MUST be 16 bytes.
00030  */
00031 void stoip6(const char *ip6addr, size_t len, void *dest)
00032 {
00033     uint8_t *addr;
00034     const char *p, *q;
00035     int_fast8_t field_no, coloncolon = -1;
00036 
00037     addr = dest;
00038 
00039     if (len > 39) { // Too long, not possible. We do not support IPv4-mapped IPv6 addresses
00040         return;
00041     }
00042 
00043     // First go forward the string, until end, noting :: position if any
00044     for (field_no = 0, p = ip6addr; (len > (size_t)(p - ip6addr)) && *p && field_no < 8; p = q + 1) {
00045         q = p;
00046         // Seek for ':' or end
00047         while (*q && (*q != ':')) {
00048             q++;
00049         }
00050         //Convert and write this part, (high-endian AKA network byte order)
00051         addr = common_write_16_bit(hex(p), addr);
00052         field_no++;
00053         //Check if we reached "::"
00054         if ((len > (size_t)(q - ip6addr)) && *q && (q[0] == ':') && (q[1] == ':')) {
00055             coloncolon = field_no;
00056             q++;
00057         }
00058     }
00059 
00060     if (coloncolon != -1) {
00061         /* Insert zeros in the appropriate place */
00062         uint_fast8_t head_size = 2 * coloncolon;
00063         uint_fast8_t inserted_size = 2 * (8 - field_no);
00064         uint_fast8_t tail_size = 16 - head_size - inserted_size;
00065         addr = dest;
00066         memmove(addr + head_size + inserted_size, addr + head_size, tail_size);
00067         memset(addr + head_size, 0, inserted_size);
00068     } else if (field_no != 8) {
00069         /* Should really report an error if we didn't get 8 fields */
00070         memset(addr, 0, 16 - field_no * 2);
00071     }
00072 }
00073 unsigned char  sipv6_prefixlength(const char *ip6addr)
00074 {
00075     char *ptr = strchr(ip6addr, '/');
00076     if (ptr) {
00077         return (unsigned char)strtoul(ptr + 1, 0, 10);
00078     }
00079     return 0;
00080 }
00081 static uint16_t hex(const char *p)
00082 {
00083     uint16_t val = 0;
00084 
00085     for (;;) {
00086         char c = *p++;
00087         if ((c >= '0') && (c <= '9')) {
00088             val = (val << 4) | (c - '0');
00089         } else if ((c >= 'A') && (c <= 'F')) {
00090             val = (val << 4) | (10 + (c - 'A'));
00091         } else if ((c >= 'a') && (c <= 'f')) {
00092             val = (val << 4) | (10 + (c - 'a'));
00093         } else {
00094             break; // Non hex character
00095         }
00096     }
00097     return val;
00098 }