diff options
Diffstat (limited to 'resolv/inet_ntop.c')
| -rw-r--r-- | resolv/inet_ntop.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/resolv/inet_ntop.c b/resolv/inet_ntop.c new file mode 100644 index 0000000..71db06d --- /dev/null +++ b/resolv/inet_ntop.c @@ -0,0 +1,189 @@ +/* Copyright (c) 1996 by Internet Software Consortium. + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS + * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE + * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL + * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR + * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS + * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS + * SOFTWARE. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char rcsid[] = "$Id$"; +#endif /* LIBC_SCCS and not lint */ + +#include <sys/param.h> +#include <sys/types.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <arpa/inet.h> +#include <arpa/nameser.h> +#include <string.h> +#include <errno.h> +#include <stdio.h> +#include "../conf/portability.h" + +/* + * WARNING: Don't even consider trying to compile this on a system where + * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. + */ + +static const char *inet_ntop4 __P((const u_char *src, char *dst, size_t size)); +static const char *inet_ntop6 __P((const u_char *src, char *dst, size_t size)); + +/* char * + * inet_ntop(af, src, dst, size) + * convert a network format address to presentation format. + * return: + * pointer to presentation format address (`dst'), or NULL (see errno). + * author: + * Paul Vixie, 1996. + */ +const char * +inet_ntop(af, src, dst, size) + int af; + const void *src; + char *dst; + size_t size; +{ + switch (af) { + case AF_INET: + return (inet_ntop4(src, dst, size)); + case AF_INET6: + return (inet_ntop6(src, dst, size)); + default: + errno = EAFNOSUPPORT; + return (NULL); + } + /* NOTREACHED */ +} + +/* const char * + * inet_ntop4(src, dst, size) + * format an IPv4 address, more or less like inet_ntoa() + * return: + * `dst' (as a const) + * notes: + * (1) uses no statics + * (2) takes a u_char* not an in_addr as input + * author: + * Paul Vixie, 1996. + */ +static const char * +inet_ntop4(src, dst, size) + const u_char *src; + char *dst; + size_t size; +{ + static const char fmt[] = "%u.%u.%u.%u"; + char tmp[sizeof "255.255.255.255"]; + + if (sprintf(tmp, fmt, src[0], src[1], src[2], src[3]) > size) { + errno = ENOSPC; + return (NULL); + } + strcpy(dst, tmp); + return (dst); +} + +/* const char * + * inet_ntop6(src, dst, size) + * convert IPv6 binary address into presentation (printable) format + * author: + * Paul Vixie, 1996. + */ +static const char * +inet_ntop6(src, dst, size) + const u_char *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. + */ + char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; + struct { int base, len; } best, cur; + u_int 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. + */ + bzero(words, sizeof words); + for (i = 0; i < IN6ADDRSZ; i++) + words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); + best.base = -1; + 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) { + if (best.base == -1 || cur.len > best.len) + best = cur; + } + if (best.base != -1 && best.len < 2) + best.base = -1; + + /* + * Format the result. + */ + tp = tmp; + 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) + *tp++ = ':'; + continue; + } + /* Are we following an initial run of 0x00s or any real hex? */ + if (i != 0) + *tp++ = ':'; + /* Is this address an encapsulated IPv4? */ + if (i == 6 && best.base == 0 && + (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { + if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) + return (NULL); + tp += strlen(tp); + break; + } + tp += sprintf(tp, "%x", words[i]); + } + /* Was it a trailing run of 0x00's? */ + if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) + *tp++ = ':'; + *tp++ = '\0'; + + /* + * Check for overflow, copy, and we're done. + */ + if ((tp - tmp) > size) { + errno = ENOSPC; + return (NULL); + } + strcpy(dst, tmp); + return (dst); +} |