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Diffstat (limited to 'addrtostr.c')
| -rw-r--r-- | addrtostr.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/addrtostr.c b/addrtostr.c new file mode 100644 index 0000000..62cc298 --- /dev/null +++ b/addrtostr.c @@ -0,0 +1,213 @@ +/* + * Copyright (c) 1999 Kungliga Tekniska Högskolan + * (Royal Institute of Technology, Stockholm, Sweden). + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the Kungliga Tekniska + * Högskolan and its contributors. + * + * 4. Neither the name of the Institute nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include "netdissect-stdinc.h" +#include "addrtostr.h" + +#include <stdio.h> +#include <string.h> + +/* + * + */ + +#ifndef IN6ADDRSZ +#define IN6ADDRSZ 16 /* IPv6 T_AAAA */ +#endif + +#ifndef INT16SZ +#define INT16SZ 2 /* word size */ +#endif + +const char * +addrtostr (const void *src, char *dst, size_t size) +{ + const u_char *srcaddr = (const u_char *)src; + const char digits[] = "0123456789"; + int i; + const char *orig_dst = dst; + + if (size < INET_ADDRSTRLEN) { + errno = ENOSPC; + return NULL; + } + for (i = 0; i < 4; ++i) { + int n = *srcaddr++; + int non_zerop = 0; + + if (non_zerop || n / 100 > 0) { + *dst++ = digits[n / 100]; + n %= 100; + non_zerop = 1; + } + if (non_zerop || n / 10 > 0) { + *dst++ = digits[n / 10]; + n %= 10; + non_zerop = 1; + } + *dst++ = digits[n]; + if (i != 3) + *dst++ = '.'; + } + *dst++ = '\0'; + return orig_dst; +} + +/* + * Convert IPv6 binary address into presentation (printable) format. + */ +const char * +addrtostr6 (const void *src, char *dst, size_t size) +{ + /* + * Note that int32_t and int16_t need only be "at least" large enough + * to contain a value of the specified size. On some systems, like + * Crays, there is no such thing as an integer variable with 16 bits. + * Keep this in mind if you think this function should have been coded + * to use pointer overlays. All the world's not a VAX. + */ + const u_char *srcaddr = (const u_char *)src; + char *dp; + size_t space_left, added_space; + int snprintfed; + struct { + int base; + int len; + } best, cur; + uint16_t words [IN6ADDRSZ / INT16SZ]; + int i; + + /* Preprocess: + * Copy the input (bytewise) array into a wordwise array. + * Find the longest run of 0x00's in src[] for :: shorthanding. + */ + for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) + words[i] = (srcaddr[2*i] << 8) | srcaddr[2*i + 1]; + + best.len = 0; + best.base = -1; + cur.len = 0; + cur.base = -1; + for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) + { + if (words[i] == 0) + { + if (cur.base == -1) + cur.base = i, cur.len = 1; + else cur.len++; + } + else if (cur.base != -1) + { + if (best.base == -1 || cur.len > best.len) + best = cur; + cur.base = -1; + } + } + if ((cur.base != -1) && (best.base == -1 || cur.len > best.len)) + best = cur; + if (best.base != -1 && best.len < 2) + best.base = -1; + + /* Format the result. + */ + dp = dst; + space_left = size; +#define APPEND_CHAR(c) \ + { \ + if (space_left == 0) { \ + errno = ENOSPC; \ + return (NULL); \ + } \ + *dp++ = c; \ + space_left--; \ + } + for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) + { + /* Are we inside the best run of 0x00's? + */ + if (best.base != -1 && i >= best.base && i < (best.base + best.len)) + { + if (i == best.base) + APPEND_CHAR(':'); + continue; + } + + /* Are we following an initial run of 0x00s or any real hex? + */ + if (i != 0) + APPEND_CHAR(':'); + + /* Is this address an encapsulated IPv4? + */ + if (i == 6 && best.base == 0 && + (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) + { + if (!addrtostr(srcaddr+12, dp, space_left)) + { + errno = ENOSPC; + return (NULL); + } + added_space = strlen(dp); + dp += added_space; + space_left -= added_space; + break; + } + snprintfed = snprintf (dp, space_left, "%x", words[i]); + if (snprintfed < 0) + return (NULL); + if ((size_t) snprintfed >= space_left) + { + errno = ENOSPC; + return (NULL); + } + dp += snprintfed; + space_left -= snprintfed; + } + + /* Was it a trailing run of 0x00's? + */ + if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) + APPEND_CHAR(':'); + APPEND_CHAR('\0'); + + return (dst); +} |