diff options
-rw-r--r-- | ares/inet_ntop.c | 240 |
1 files changed, 127 insertions, 113 deletions
diff --git a/ares/inet_ntop.c b/ares/inet_ntop.c index 60d91b956..74192c1a8 100644 --- a/ares/inet_ntop.c +++ b/ares/inet_ntop.c @@ -1,3 +1,5 @@ +/* $Id$ */ + /* Copyright (c) 1996 by Internet Software Consortium. * * Permission to use, copy, modify, and distribute this software for any @@ -63,144 +65,156 @@ static const char *inet_ntop6(const unsigned char *src, char *dst, size_t size); /* char * * inet_ntop(af, src, dst, size) - * convert a network format address to presentation format. + * convert a network format address to presentation format. * return: - * pointer to presentation format address (`dst'), or NULL (see errno). + * pointer to presentation format address (`dst'), or NULL (see errno). * author: - * Paul Vixie, 1996. + * Paul Vixie, 1996. */ const char * ares_inet_ntop(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 */ + 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() + * format an IPv4 address, more or less like inet_ntoa() * return: - * `dst' (as a const) + * `dst' (as a const) * notes: - * (1) uses no statics - * (2) takes a unsigned char* not an in_addr as input + * (1) uses no statics + * (2) takes a unsigned char* not an in_addr as input * author: - * Paul Vixie, 1996. + * 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"]; - - if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) > size) { - errno = ENOSPC; - return (NULL); - } - strcpy(dst, tmp); - return (dst); + 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 + * convert IPv6 binary address into presentation (printable) format * author: - * Paul Vixie, 1996. + * Paul Vixie, 1996. */ 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 = { 0,0 }, cur = { 0,0 }; - 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; - cur.base = -1; - 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 == 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) == (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); - } - strcpy(dst, tmp); - return (dst); + /* + * 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 = { 0,0 }, cur = { 0,0 }; + 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; + cur.base = -1; + 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 == 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) == (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); + } + strcpy(dst, tmp); + return (dst); } - #endif + |