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mbed client lightswitch demo
Dependencies: mbed Socket lwip-eth lwip-sys lwip
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Diff: nanostack-libservice/source/libip6string/ip6tos.c
- Revision:
- 11:cada08fc8a70
diff -r 1280c4c21987 -r cada08fc8a70 nanostack-libservice/source/libip6string/ip6tos.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/nanostack-libservice/source/libip6string/ip6tos.c Thu Jun 09 17:08:36 2016 +0000 @@ -0,0 +1,95 @@ +/* + * Copyright (c) 2014-2015 ARM Limited. All rights reserved. + * SPDX-License-Identifier: Apache-2.0 + * Licensed under the Apache License, Version 2.0 (the License); you may + * not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an AS IS BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +#include <stdio.h> +#include <inttypes.h> +#include "ip6string.h" + +/** + * Print binary IPv6 address to a string. + * String must contain enough room for full address, 40 bytes exact. + * IPv4 tunneling addresses are not covered. + * \param addr IPv6 address. + * \p buffer to write string to. + */ +void ip6tos(const void *ip6addr, char *p) +{ + uint_fast8_t zero_start = 255, zero_len = 1; + const uint8_t *addr = ip6addr; + uint_fast16_t part; + + /* Follow RFC 5952 - pre-scan for longest run of zeros */ + for (uint_fast8_t n = 0; n < 8; n++) { + part = *addr++; + part = (part << 8) | *addr++; + if (part != 0) { + continue; + } + + /* We're at the start of a run of zeros - scan to non-zero (or end) */ + uint_fast8_t n0 = n; + for (n = n0 + 1; n < 8; n++) { + part = *addr++; + part = (part << 8) | *addr++; + if (part != 0) { + break; + } + } + + /* Now n0->initial zero of run, n->after final zero in run. Is this the + * longest run yet? If equal, we stick with the previous one - RFC 5952 + * S4.2.3. Note that zero_len being initialised to 1 stops us + * shortening a 1-part run (S4.2.2.) + */ + if (n - n0 > zero_len) { + zero_start = n0; + zero_len = n - n0; + } + + /* Continue scan for initial zeros from part n+1 - we've already + * consumed part n, and know it's non-zero. */ + } + + /* Now go back and print, jumping over any zero run */ + addr = ip6addr; + for (uint_fast8_t n = 0; n < 8;) { + if (n == zero_start) { + if (n == 0) { + *p++ = ':'; + } + *p++ = ':'; + addr += 2 * zero_len; + n += zero_len; + continue; + } + + part = *addr++; + part = (part << 8) | *addr++; + n++; + + p += sprintf(p, "%"PRIxFAST16, part); + + /* One iteration writes "part:" rather than ":part", and has the + * explicit check for n == 8 below, to allow easy extension for + * IPv4-in-IPv6-type addresses ("xxxx::xxxx:a.b.c.d"): we'd just + * run the same loop for 6 parts, and output would then finish with the + * required : or ::, ready for "a.b.c.d" to be tacked on. + */ + if (n != 8) { + *p++ = ':'; + } + } + *p++ = '\0'; +}