Ivo Noorhoff / UIPEthernet

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utility/os2_ip6tos.c@16:269f652b4d0b, 2020-06-05 (annotated)

Committer:
hudakz
Date:
Fri Jun 05 15:12:21 2020 +0000
Revision:
16:269f652b4d0b
Parent:
utility/ip6tos.c@14:7648334eb41b 
Library for ENC28J60 Ethernet modules.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hudakz 14:7648334eb41b 1 /*
hudakz 14:7648334eb41b 2 * Copyright (c) 2014-2015 ARM Limited. All rights reserved.
hudakz 14:7648334eb41b 3 * SPDX-License-Identifier: Apache-2.0
hudakz 14:7648334eb41b 4 * Licensed under the Apache License, Version 2.0 (the License); you may
hudakz 14:7648334eb41b 5 * not use this file except in compliance with the License.
hudakz 14:7648334eb41b 6 * You may obtain a copy of the License at
hudakz 14:7648334eb41b 7 *
hudakz 14:7648334eb41b 8 * http://www.apache.org/licenses/LICENSE-2.0
hudakz 14:7648334eb41b 9 *
hudakz 14:7648334eb41b 10 * Unless required by applicable law or agreed to in writing, software
hudakz 14:7648334eb41b 11 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
hudakz 14:7648334eb41b 12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
hudakz 14:7648334eb41b 13 * See the License for the specific language governing permissions and
hudakz 14:7648334eb41b 14 * limitations under the License.
hudakz 14:7648334eb41b 15 */
hudakz 14:7648334eb41b 16 #include "mbed_version.h"
hudakz 14:7648334eb41b 17
hudakz 14:7648334eb41b 18 #if MBED_MAJOR_VERSION == 2
hudakz 14:7648334eb41b 19
hudakz 14:7648334eb41b 20 #include <stdio.h>
hudakz 14:7648334eb41b 21 #include <string.h>
hudakz 14:7648334eb41b 22 #include "common_functions.h"
hudakz 14:7648334eb41b 23 #include "ip6string.h"
hudakz 14:7648334eb41b 24
hudakz 14:7648334eb41b 25 /**
hudakz 14:7648334eb41b 26 * Print binary IPv6 address to a string.
hudakz 14:7648334eb41b 27 * String must contain enough room for full address, 40 bytes exact.
hudakz 14:7648334eb41b 28 * IPv4 tunneling addresses are not covered.
hudakz 14:7648334eb41b 29 * \param addr IPv6 address.
hudakz 14:7648334eb41b 30 * \p buffer to write string to.
hudakz 14:7648334eb41b 31 */
hudakz 14:7648334eb41b 32 uint_fast8_t ip6tos(const void *ip6addr, char *p)
hudakz 14:7648334eb41b 33 {
hudakz 14:7648334eb41b 34 char *p_orig = p;
hudakz 14:7648334eb41b 35 uint_fast8_t zero_start = 255, zero_len = 1;
hudakz 14:7648334eb41b 36 const uint8_t *addr = ip6addr;
hudakz 14:7648334eb41b 37 uint_fast16_t part;
hudakz 14:7648334eb41b 38
hudakz 14:7648334eb41b 39 /* Follow RFC 5952 - pre-scan for longest run of zeros */
hudakz 14:7648334eb41b 40 for (uint_fast8_t n = 0; n < 8; n++) {
hudakz 14:7648334eb41b 41 part = *addr++;
hudakz 14:7648334eb41b 42 part = (part << 8) | *addr++;
hudakz 14:7648334eb41b 43 if (part != 0) {
hudakz 14:7648334eb41b 44 continue;
hudakz 14:7648334eb41b 45 }
hudakz 14:7648334eb41b 46
hudakz 14:7648334eb41b 47 /* We're at the start of a run of zeros - scan to non-zero (or end) */
hudakz 14:7648334eb41b 48 uint_fast8_t n0 = n;
hudakz 14:7648334eb41b 49 for (n = n0 + 1; n < 8; n++) {
hudakz 14:7648334eb41b 50 part = *addr++;
hudakz 14:7648334eb41b 51 part = (part << 8) | *addr++;
hudakz 14:7648334eb41b 52 if (part != 0) {
hudakz 14:7648334eb41b 53 break;
hudakz 14:7648334eb41b 54 }
hudakz 14:7648334eb41b 55 }
hudakz 14:7648334eb41b 56
hudakz 14:7648334eb41b 57 /* Now n0->initial zero of run, n->after final zero in run. Is this the
hudakz 14:7648334eb41b 58 * longest run yet? If equal, we stick with the previous one - RFC 5952
hudakz 14:7648334eb41b 59 * S4.2.3. Note that zero_len being initialised to 1 stops us
hudakz 14:7648334eb41b 60 * shortening a 1-part run (S4.2.2.)
hudakz 14:7648334eb41b 61 */
hudakz 14:7648334eb41b 62 if (n - n0 > zero_len) {
hudakz 14:7648334eb41b 63 zero_start = n0;
hudakz 14:7648334eb41b 64 zero_len = n - n0;
hudakz 14:7648334eb41b 65 }
hudakz 14:7648334eb41b 66
hudakz 14:7648334eb41b 67 /* Continue scan for initial zeros from part n+1 - we've already
hudakz 14:7648334eb41b 68 * consumed part n, and know it's non-zero. */
hudakz 14:7648334eb41b 69 }
hudakz 14:7648334eb41b 70
hudakz 14:7648334eb41b 71 /* Now go back and print, jumping over any zero run */
hudakz 14:7648334eb41b 72 addr = ip6addr;
hudakz 14:7648334eb41b 73 for (uint_fast8_t n = 0; n < 8;) {
hudakz 14:7648334eb41b 74 if (n == zero_start) {
hudakz 14:7648334eb41b 75 if (n == 0) {
hudakz 14:7648334eb41b 76 *p++ = ':';
hudakz 14:7648334eb41b 77 }
hudakz 14:7648334eb41b 78 *p++ = ':';
hudakz 14:7648334eb41b 79 addr += 2 * zero_len;
hudakz 14:7648334eb41b 80 n += zero_len;
hudakz 14:7648334eb41b 81 continue;
hudakz 14:7648334eb41b 82 }
hudakz 14:7648334eb41b 83
hudakz 14:7648334eb41b 84 part = *addr++;
hudakz 14:7648334eb41b 85 part = (part << 8) | *addr++;
hudakz 14:7648334eb41b 86 n++;
hudakz 14:7648334eb41b 87
hudakz 14:7648334eb41b 88 p += sprintf(p, "%"PRIxFAST16, part);
hudakz 14:7648334eb41b 89
hudakz 14:7648334eb41b 90 /* One iteration writes "part:" rather than ":part", and has the
hudakz 14:7648334eb41b 91 * explicit check for n == 8 below, to allow easy extension for
hudakz 14:7648334eb41b 92 * IPv4-in-IPv6-type addresses ("xxxx::xxxx:a.b.c.d"): we'd just
hudakz 14:7648334eb41b 93 * run the same loop for 6 parts, and output would then finish with the
hudakz 14:7648334eb41b 94 * required : or ::, ready for "a.b.c.d" to be tacked on.
hudakz 14:7648334eb41b 95 */
hudakz 14:7648334eb41b 96 if (n != 8) {
hudakz 14:7648334eb41b 97 *p++ = ':';
hudakz 14:7648334eb41b 98 }
hudakz 14:7648334eb41b 99 }
hudakz 14:7648334eb41b 100 *p = '\0';
hudakz 14:7648334eb41b 101
hudakz 14:7648334eb41b 102 // Return length of generated string, excluding the terminating null character
hudakz 14:7648334eb41b 103 return p - p_orig;
hudakz 14:7648334eb41b 104 }
hudakz 14:7648334eb41b 105
hudakz 14:7648334eb41b 106 uint_fast8_t ip6_prefix_tos(const void *prefix, uint_fast8_t prefix_len, char *p)
hudakz 14:7648334eb41b 107 {
hudakz 14:7648334eb41b 108 char *wptr = p;
hudakz 14:7648334eb41b 109 uint8_t addr[16] = {0};
hudakz 14:7648334eb41b 110
hudakz 14:7648334eb41b 111 if (prefix_len > 128) {
hudakz 14:7648334eb41b 112 return 0;
hudakz 14:7648334eb41b 113 }
hudakz 14:7648334eb41b 114
hudakz 14:7648334eb41b 115 // Generate prefix part of the string
hudakz 14:7648334eb41b 116 bitcopy(addr, prefix, prefix_len);
hudakz 14:7648334eb41b 117 wptr += ip6tos(addr, wptr);
hudakz 14:7648334eb41b 118 // Add the prefix length part of the string
hudakz 14:7648334eb41b 119 wptr += sprintf(wptr, "/%"PRIuFAST8, prefix_len);
hudakz 14:7648334eb41b 120
hudakz 14:7648334eb41b 121 // Return total length of generated string
hudakz 14:7648334eb41b 122 return wptr - p;
hudakz 14:7648334eb41b 123 }
hudakz 14:7648334eb41b 124 #endif