/* inet_ntop.c -- convert IPv4 and IPv6 addresses from binary to text form Copyright (C) 2005-2006, 2008-2020 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, see . */ /* * Copyright (c) 1996-1999 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. */ #include /* Specification. */ #include /* Use this to suppress gcc's "...may be used before initialized" warnings. Beware: The Code argument must not contain commas. */ #ifndef IF_LINT # if defined GCC_LINT || defined lint # define IF_LINT(Code) Code # else # define IF_LINT(Code) /* empty */ # endif #endif #if HAVE_DECL_INET_NTOP # undef inet_ntop const char * rpl_inet_ntop (int af, const void *restrict src, char *restrict dst, socklen_t cnt) { return inet_ntop (af, src, dst, cnt); } #else # include # include # include # define NS_IN6ADDRSZ 16 # define NS_INT16SZ 2 /* * 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. */ typedef int verify_int_size[4 <= sizeof (int) ? 1 : -1]; static const char *inet_ntop4 (const unsigned char *src, char *dst, socklen_t size); # if HAVE_IPV6 static const char *inet_ntop6 (const unsigned char *src, char *dst, socklen_t size); # endif /* 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 (int af, const void *restrict src, char *restrict dst, socklen_t cnt) { switch (af) { # if HAVE_IPV4 case AF_INET: return (inet_ntop4 (src, dst, cnt)); # endif # if HAVE_IPV6 case AF_INET6: return (inet_ntop6 (src, dst, cnt)); # endif default: errno = EAFNOSUPPORT; return (NULL); } /* NOTREACHED */ } /* const char * * inet_ntop4(src, dst, size) * format an IPv4 address * 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 (const unsigned char *src, char *dst, socklen_t size) { char tmp[sizeof "255.255.255.255"]; int len; len = sprintf (tmp, "%u.%u.%u.%u", src[0], src[1], src[2], src[3]); if (len < 0) return NULL; if (len > size) { errno = ENOSPC; return NULL; } return strcpy (dst, tmp); } # if HAVE_IPV6 /* const char * * inet_ntop6(src, dst, size) * convert IPv6 binary address into presentation (printable) format * author: * Paul Vixie, 1996. */ static const char * inet_ntop6 (const unsigned char *src, char *dst, socklen_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 += 2) words[i / 2] = (src[i] << 8) | src[i + 1]; best.base = -1; cur.base = -1; IF_LINT(best.len = 0); IF_LINT(cur.len = 0); 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; } { int len = sprintf (tp, "%x", words[i]); if (len < 0) return NULL; tp += len; } } /* 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 ((socklen_t) (tp - tmp) > size) { errno = ENOSPC; return NULL; } return strcpy (dst, tmp); } # endif #endif