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/* inet_XtoX.c
* Simple implementation of the following functions: * inet_ntop(), inet_ntoa(), inet_pton(), inet_aton(). * * Differences from traditional implementaitons: * o modifies destination buffers even on error return. * o no fancy (hex, or 1.2) input support in inet_aton() * o inet_aton() does not accept junk after an IP address. * o inet_ntop(AF_INET) requires at least 16 bytes in dest, * and inet_ntop(AF_INET6) at least 40 bytes * (traditional inet_ntop() will try to fit anyway) * * Compile with -Dinet_XtoX_prefix=pfx_ to have pfx_*() instead of inet_*() * Compile with -Dinet_XtoX_no_ntop or -Dinet_XtoX_no_pton * to disable net2str or str2net conversions. * * #define inet_XtoX_prototypes and #include "this_file.c" * to get function prototypes only (but not for inet_ntoa()). * #define inet_XtoX_decl to be `static' for static visibility, * or use __declspec(dllexport) or somesuch... * * Compile with -DTEST to test against stock implementation. * * Written by Michael Tokarev. Public domain. */
#ifdef inet_XtoX_prototypes
struct in_addr;
#else
#include <errno.h>
#ifdef TEST
# include <netinet/in.h>
# include <sys/socket.h>
# include <arpa/inet.h>
# include <stdio.h>
# include <stdlib.h>
# include <unistd.h>
# include <string.h>
# undef inet_XtoX_prefix
# define inet_XtoX_prefix mjt_inet_
# undef inet_XtoX_no_ntop
# undef inet_XtoX_no_pton
#else /* !TEST */
struct in_addr { /* declare it here to avoid messing with headers */ unsigned char x[4]; };
#endif /* TEST */
#endif /* inet_XtoX_prototypes */
#ifndef inet_XtoX_prefix
# define inet_XtoX_prefix inet_
#endif
#ifndef inet_XtoX_decl
# define inet_XtoX_decl /*empty*/
#endif
#define cc2_(x,y) cc2__(x,y)
#define cc2__(x,y) x##y
#define fn(x) cc2_(inet_XtoX_prefix,x)
#ifndef inet_XtoX_no_ntop
inet_XtoX_decl const char * fn(ntop)(int af, const void *src, char *dst, unsigned size);
#ifndef inet_XtoX_prototypes
static int mjt_ntop4(const void *_src, char *dst, int size) { unsigned i, x, r; char *p; const unsigned char *s = _src; if (size < 4*4) /* for simplicity, disallow non-max-size buffer */ return 0; for (i = 0, p = dst; i < 4; ++i) { if (i) *p++ = '.'; x = r = s[i]; if (x > 99) { *p++ = (char)(r / 100 + '0'); r %= 100; } if (x > 9) { *p++ = (char)(r / 10 + '0'); r %= 10; } *p++ = (char)(r + '0'); } *p = '\0'; return 1; }
static char *hexc(char *p, unsigned x) { static char hex[16] = "0123456789abcdef"; if (x > 0x0fff) *p++ = hex[(x >>12) & 15]; if (x > 0x00ff) *p++ = hex[(x >> 8) & 15]; if (x > 0x000f) *p++ = hex[(x >> 4) & 15]; *p++ = hex[x & 15]; return p; }
static int mjt_ntop6(const void *_src, char *dst, int size) { unsigned i; unsigned short w[8]; unsigned bs = 0, cs = 0; unsigned bl = 0, cl = 0; char *p; const unsigned char *s = _src;
if (size < 40) /* for simplicity, disallow non-max-size buffer */ return 0;
for(i = 0; i < 8; ++i, s += 2) { w[i] = (((unsigned short)(s[0])) << 8) | s[1]; if (!w[i]) { if (!cl++) cs = i; } else { if (cl > bl) bl = cl, bs = cs; } } if (cl > bl) bl = cl, bs = cs; p = dst; if (bl == 1) bl = 0; if (bl) { for(i = 0; i < bs; ++i) { if (i) *p++ = ':'; p = hexc(p, w[i]); } *p++ = ':'; i += bl; if (i == 8) *p++ = ':'; } else i = 0; for(; i < 8; ++i) { if (i) *p++ = ':'; if (i == 6 && !bs && (bl == 6 || (bl == 5 && w[5] == 0xffff))) return mjt_ntop4(s - 4, p, size - (p - dst)); p = hexc(p, w[i]); } *p = '\0'; return 1; }
inet_XtoX_decl const char * fn(ntop)(int af, const void *src, char *dst, unsigned size) { switch(af) { /* don't use AF_*: don't mess with headers */ case 2: /* AF_INET */ if (mjt_ntop4(src, dst, size)) return dst; break; case 10: /* AF_INET6 */ if (mjt_ntop6(src, dst, size)) return dst; break; default: errno = EAFNOSUPPORT; return (char*)0; } errno = ENOSPC; return (char*)0; }
inet_XtoX_decl const char * fn(ntoa)(struct in_addr addr) { static char buf[4*4]; mjt_ntop4(&addr, buf, sizeof(buf)); return buf; }
#endif /* inet_XtoX_prototypes */
#endif /* inet_XtoX_no_ntop */
#ifndef inet_XtoX_no_pton
inet_XtoX_decl int fn(pton)(int af, const char *src, void *dst); inet_XtoX_decl int fn(aton)(const char *src, struct in_addr *addr);
#ifndef inet_XtoX_prototypes
static int mjt_pton4(const char *c, void *dst) { unsigned char *a = dst; unsigned n, o; for (n = 0; n < 4; ++n) { if (*c < '0' || *c > '9') return 0; o = *c++ - '0'; while(*c >= '0' && *c <= '9') if ((o = o * 10 + (*c++ - '0')) > 255) return 0; if (*c++ != (n == 3 ? '\0' : '.')) return 0; *a++ = (unsigned char)o; } return 1; }
static int mjt_pton6(const char *c, void *dst) { unsigned short w[8], *a = w, *z, *i; unsigned v, o; const char *sc; unsigned char *d = dst; if (*c != ':') z = (unsigned short*)0; else if (*++c != ':') return 0; else ++c, z = a; i = 0; for(;;) { v = 0; sc = c; for(;;) { if (*c >= '0' && *c <= '9') o = *c - '0'; else if (*c >= 'a' && *c <= 'f') o = *c - 'a' + 10; else if (*c >= 'A' && *c <= 'F') o = *c - 'A' + 10; else break; v = (v << 4) | o; if (v > 0xffff) return 0; ++c; } if (sc == c) { if (z == a && !*c) break; else return 0; } if (*c == ':') { if (a >= w + 8) return 0; *a++ = v; if (*++c == ':') { if (z) return 0; z = a; if (!*++c) break; } } else if (!*c) { if (a >= w + 8) return 0; *a++ = v; break; } else if (*c == '.') { if (a > w + 6) return 0; if (!mjt_pton4(sc, d)) return 0; *a++ = ((unsigned)(d[0]) << 8) | d[1]; *a++ = ((unsigned)(d[2]) << 8) | d[3]; break; } else return 0; } v = w + 8 - a; if ((v && !z) || (!v && z)) return 0; for(i = w; ; ++i) { if (i == z) while(v--) { *d++ = '\0'; *d++ = '\0'; } if (i >= a) break; *d++ = (unsigned char)((*i >> 8) & 255); *d++ = (unsigned char)(*i & 255); } return 1; }
inet_XtoX_decl int fn(pton)(int af, const char *src, void *dst) { switch(af) { /* don't use AF_*: don't mess with headers */ case 2 /* AF_INET */: return mjt_pton4(src, dst); case 10 /* AF_INET6 */: return mjt_pton6(src, dst); default: errno = EAFNOSUPPORT; return -1; } }
inet_XtoX_decl int fn(aton)(const char *src, struct in_addr *addr) { return mjt_pton4(src, addr); }
#endif /* inet_XtoX_prototypes */
#endif /* inet_XtoX_no_pton */
#ifdef TEST
int main(int argc, char **argv) { int i; char n0[16], n1[16]; char p0[64], p1[64]; int af = AF_INET; int pl = sizeof(p0); int r0, r1; const char *s0, *s1;
while((i = getopt(argc, argv, "46a:p:")) != EOF) switch(i) { case '4': af = AF_INET; break; case '6': af = AF_INET6; break; case 'a': case 'p': pl = atoi(optarg); break; default: return 1; } for(i = optind; i < argc; ++i) { char *a = argv[i];
printf("%s:\n", a); r0 = inet_pton(af, a, n0); printf(" p2n stock: %s\n", (r0 < 0 ? "(notsupp)" : !r0 ? "(inval)" : fn(ntop)(af,n0,p0,sizeof(p0)))); r1 = fn(pton)(af, a, n1); printf(" p2n this : %s\n", (r1 < 0 ? "(notsupp)" : !r1 ? "(inval)" : fn(ntop)(af,n1,p1,sizeof(p1))));
if ((r0 > 0) != (r1 > 0) || (r0 > 0 && r1 > 0 && memcmp(n0, n1, af == AF_INET ? 4 : 16) != 0)) printf(" DIFFER!\n");
s0 = inet_ntop(af, n1, p0, pl); printf(" n2p stock: %s\n", s0 ? s0 : "(inval)"); s1 = fn(ntop)(af, n1, p1, pl); printf(" n2p this : %s\n", s1 ? s1 : "(inval)"); if ((s0 != 0) != (s1 != 0) || (s0 && s1 && strcmp(s0, s1) != 0)) printf(" DIFFER!\n");
} return 0; }
#endif /* TEST */
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