Annotation of embedaddon/rsync/lib/inet_ntop.c, revision 1.1
1.1 ! misho 1: /*
! 2: * Copyright (C) 1996-2001 Internet Software Consortium.
! 3: *
! 4: * Permission to use, copy, modify, and distribute this software for any
! 5: * purpose with or without fee is hereby granted, provided that the above
! 6: * copyright notice and this permission notice appear in all copies.
! 7: *
! 8: * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
! 9: * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
! 10: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
! 11: * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
! 12: * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
! 13: * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
! 14: * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
! 15: * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
! 16: */
! 17:
! 18:
! 19: #include "rsync.h"
! 20:
! 21: #define NS_INT16SZ 2
! 22: #define NS_IN6ADDRSZ 16
! 23:
! 24: /*
! 25: * WARNING: Don't even consider trying to compile this on a system where
! 26: * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
! 27: */
! 28:
! 29: static const char *inet_ntop4(const unsigned char *src, char *dst,
! 30: size_t size);
! 31:
! 32: #ifdef AF_INET6
! 33: static const char *inet_ntop6(const unsigned char *src, char *dst,
! 34: size_t size);
! 35: #endif
! 36:
! 37: /* char *
! 38: * isc_net_ntop(af, src, dst, size)
! 39: * convert a network format address to presentation format.
! 40: * return:
! 41: * pointer to presentation format address (`dst'), or NULL (see errno).
! 42: * author:
! 43: * Paul Vixie, 1996.
! 44: */
! 45: const char *
! 46: inet_ntop(int af, const void *src, char *dst, size_t size)
! 47: {
! 48: switch (af) {
! 49: case AF_INET:
! 50: return (inet_ntop4(src, dst, size));
! 51: #ifdef AF_INET6
! 52: case AF_INET6:
! 53: return (inet_ntop6(src, dst, size));
! 54: #endif
! 55: default:
! 56: errno = EAFNOSUPPORT;
! 57: return (NULL);
! 58: }
! 59: /* NOTREACHED */
! 60: }
! 61:
! 62: /* const char *
! 63: * inet_ntop4(src, dst, size)
! 64: * format an IPv4 address
! 65: * return:
! 66: * `dst' (as a const)
! 67: * notes:
! 68: * (1) uses no statics
! 69: * (2) takes a unsigned char* not an in_addr as input
! 70: * author:
! 71: * Paul Vixie, 1996.
! 72: */
! 73: static const char *
! 74: inet_ntop4(const unsigned char *src, char *dst, size_t size)
! 75: {
! 76: static const char *fmt = "%u.%u.%u.%u";
! 77: char tmp[sizeof "255.255.255.255"];
! 78: size_t len;
! 79:
! 80: len = snprintf(tmp, sizeof tmp, fmt, src[0], src[1], src[2], src[3]);
! 81: if (len >= size) {
! 82: errno = ENOSPC;
! 83: return (NULL);
! 84: }
! 85: memcpy(dst, tmp, len + 1);
! 86:
! 87: return (dst);
! 88: }
! 89:
! 90: /* const char *
! 91: * isc_inet_ntop6(src, dst, size)
! 92: * convert IPv6 binary address into presentation (printable) format
! 93: * author:
! 94: * Paul Vixie, 1996.
! 95: */
! 96: #ifdef AF_INET6
! 97: static const char *
! 98: inet_ntop6(const unsigned char *src, char *dst, size_t size)
! 99: {
! 100: /*
! 101: * Note that int32_t and int16_t need only be "at least" large enough
! 102: * to contain a value of the specified size. On some systems, like
! 103: * Crays, there is no such thing as an integer variable with 16 bits.
! 104: * Keep this in mind if you think this function should have been coded
! 105: * to use pointer overlays. All the world's not a VAX.
! 106: */
! 107: char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
! 108: struct { int base, len; } best, cur;
! 109: unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
! 110: int i, inc;
! 111:
! 112: /*
! 113: * Preprocess:
! 114: * Copy the input (bytewise) array into a wordwise array.
! 115: * Find the longest run of 0x00's in src[] for :: shorthanding.
! 116: */
! 117: memset(words, '\0', sizeof words);
! 118: for (i = 0; i < NS_IN6ADDRSZ; i++)
! 119: words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
! 120: best.base = -1;
! 121: cur.base = -1;
! 122: for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
! 123: if (words[i] == 0) {
! 124: if (cur.base == -1)
! 125: cur.base = i, cur.len = 1;
! 126: else
! 127: cur.len++;
! 128: } else {
! 129: if (cur.base != -1) {
! 130: if (best.base == -1 || cur.len > best.len)
! 131: best = cur;
! 132: cur.base = -1;
! 133: }
! 134: }
! 135: }
! 136: if (cur.base != -1) {
! 137: if (best.base == -1 || cur.len > best.len)
! 138: best = cur;
! 139: }
! 140: if (best.base != -1 && best.len < 2)
! 141: best.base = -1;
! 142:
! 143: /*
! 144: * Format the result.
! 145: */
! 146: tp = tmp;
! 147: for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
! 148: /* Are we inside the best run of 0x00's? */
! 149: if (best.base != -1 && i >= best.base &&
! 150: i < (best.base + best.len)) {
! 151: if (i == best.base)
! 152: *tp++ = ':';
! 153: continue;
! 154: }
! 155: /* Are we following an initial run of 0x00s or any real hex? */
! 156: if (i != 0)
! 157: *tp++ = ':';
! 158: /* Is this address an encapsulated IPv4? */
! 159: if (i == 6 && best.base == 0 &&
! 160: (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
! 161: if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
! 162: return (NULL);
! 163: tp += strlen(tp);
! 164: break;
! 165: }
! 166: inc = snprintf(tp, 5, "%x", words[i]);
! 167: assert(inc < 5);
! 168: tp += inc;
! 169: }
! 170: /* Was it a trailing run of 0x00's? */
! 171: if (best.base != -1 && (best.base + best.len) ==
! 172: (NS_IN6ADDRSZ / NS_INT16SZ))
! 173: *tp++ = ':';
! 174: *tp++ = '\0';
! 175:
! 176: /*
! 177: * Check for overflow, copy, and we're done.
! 178: */
! 179: if ((size_t)(tp - tmp) > size) {
! 180: errno = ENOSPC;
! 181: return (NULL);
! 182: }
! 183: memcpy(dst, tmp, tp - tmp);
! 184: return (dst);
! 185: }
! 186: #endif /* AF_INET6 */
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