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Diffstat (limited to '')
| -rw-r--r-- | lib/isc/inet_ntop.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/lib/isc/inet_ntop.c b/lib/isc/inet_ntop.c new file mode 100644 index 0000000..fb06f85 --- /dev/null +++ b/lib/isc/inet_ntop.c @@ -0,0 +1,196 @@ +/* + * Copyright (C) Internet Systems Consortium, Inc. ("ISC") + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + * + * See the COPYRIGHT file distributed with this work for additional + * information regarding copyright ownership. + */ + +/*! \file */ + +#include <config.h> + +#include <errno.h> +#include <stdio.h> +#include <inttypes.h> +#include <string.h> + +#include <isc/net.h> +#include <isc/print.h> +#include <isc/string.h> +#include <isc/util.h> + +#define NS_INT16SZ 2 +#define NS_IN6ADDRSZ 16 + +/* + * 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(const unsigned char *src, char *dst, + size_t size); + +#ifdef AF_INET6 +static const char *inet_ntop6(const unsigned char *src, char *dst, + size_t size); +#endif + +/*! char * + * isc_net_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 * +isc_net_ntop(int af, const void *src, char *dst, size_t size) +{ + switch (af) { + case AF_INET: + return (inet_ntop4(src, dst, size)); +#ifdef AF_INET6 + case AF_INET6: + return (inet_ntop6(src, dst, size)); +#endif + default: + errno = EAFNOSUPPORT; + return (NULL); + } + /* NOTREACHED */ +} + +/*! const char * + * inet_ntop4(src, dst, size) + * format an IPv4 address + * \return + * `dst' (as a const) + * \note + * (1) uses no statics + * \note + * (2) takes a unsigned char* not an in_addr as input + * \author + * Paul Vixie, 1996. + */ +static const char * +inet_ntop4(const unsigned char *src, char *dst, size_t size) +{ + static const char *fmt = "%u.%u.%u.%u"; + char tmp[sizeof("255.255.255.255")]; + int n; + + + n = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]); + if (n < 0 || (size_t)n >= size) { + errno = ENOSPC; + return (NULL); + } + strlcpy(dst, tmp, size); + + return (dst); +} + +/*! const char * + * isc_inet_ntop6(src, dst, size) + * convert IPv6 binary address into presentation (printable) format + * \author + * Paul Vixie, 1996. + */ +#ifdef AF_INET6 +static const char * +inet_ntop6(const unsigned 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; + unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ]; + int i; + + /* + * Preprocess: + * Copy the input (bytewise) array into a wordwise array. + * Find the longest run of 0x00's in src[] for :: shorthanding. + */ + memset(words, '\0', sizeof(words)); + for (i = 0; i < NS_IN6ADDRSZ; i++) + words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); + best.base = -1; + best.len = 0; /* silence compiler */ + cur.base = -1; + cur.len = 0; /* silence compiler */ + for (i = 0; i < (NS_IN6ADDRSZ / NS_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 < (NS_IN6ADDRSZ / NS_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 == 7 && words[7] != 0x0001) || + (best.len == 5 && words[5] == 0xffff))) { + if (!inet_ntop4(src+12, tp, + sizeof(tmp) - (tp - tmp))) + return (NULL); + tp += strlen(tp); + break; + } + INSIST((size_t)(tp - tmp) < sizeof(tmp)); + tp += snprintf(tp, sizeof(tmp) - (tp - tmp), "%x", words[i]); + } + /* Was it a trailing run of 0x00's? */ + if (best.base != -1 && (best.base + best.len) == + (NS_IN6ADDRSZ / NS_INT16SZ)) + *tp++ = ':'; + *tp++ = '\0'; + + /* + * Check for overflow, copy, and we're done. + */ + if ((size_t)(tp - tmp) > size) { + errno = ENOSPC; + return (NULL); + } + strlcpy(dst, tmp, size); + return (dst); +} +#endif /* AF_INET6 */ |