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/* Copyright (c) 2003-2004, Roger Dingledine
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2018, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file ipv6.c
* \brief Functions for encoding and decoding IPv6 addresses
*
* (Because these functions are generic, they can also handle IPv4 addresses).
**/
#include "lib/net/ipv6.h"
#include "lib/net/ipv4.h"
#include "lib/string/util_string.h"
#include "lib/string/compat_string.h"
#include "lib/string/compat_ctype.h"
#include "lib/string/printf.h"
#include "lib/string/scanf.h"
#include "lib/log/util_bug.h"
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#include <stdlib.h>
#include <string.h>
/** Given <b>af</b>==AF_INET and <b>src</b> a struct in_addr, or
* <b>af</b>==AF_INET6 and <b>src</b> a struct in6_addr, try to format the
* address and store it in the <b>len</b>-byte buffer <b>dst</b>. Returns
* <b>dst</b> on success, NULL on failure.
*
* (Like inet_ntop(af,src,dst,len), but works on platforms that don't have it:
* Tor sometimes needs to format ipv6 addresses even on platforms without ipv6
* support.) */
const char *
tor_inet_ntop(int af, const void *src, char *dst, size_t len)
{
if (af == AF_INET) {
if (tor_inet_ntoa(src, dst, len) < 0)
return NULL;
else
return dst;
} else if (af == AF_INET6) {
const struct in6_addr *addr = src;
char buf[64], *cp;
int longestGapLen = 0, longestGapPos = -1, i,
curGapPos = -1, curGapLen = 0;
uint16_t words[8];
for (i = 0; i < 8; ++i) {
words[i] = (((uint16_t)addr->s6_addr[2*i])<<8) + addr->s6_addr[2*i+1];
}
if (words[0] == 0 && words[1] == 0 && words[2] == 0 && words[3] == 0 &&
words[4] == 0 && ((words[5] == 0 && words[6] && words[7]) ||
(words[5] == 0xffff))) {
/* This is an IPv4 address. */
if (words[5] == 0) {
tor_snprintf(buf, sizeof(buf), "::%d.%d.%d.%d",
addr->s6_addr[12], addr->s6_addr[13],
addr->s6_addr[14], addr->s6_addr[15]);
} else {
tor_snprintf(buf, sizeof(buf), "::%x:%d.%d.%d.%d", words[5],
addr->s6_addr[12], addr->s6_addr[13],
addr->s6_addr[14], addr->s6_addr[15]);
}
if ((strlen(buf) + 1) > len) /* +1 for \0 */
return NULL;
strlcpy(dst, buf, len);
return dst;
}
i = 0;
while (i < 8) {
if (words[i] == 0) {
curGapPos = i++;
curGapLen = 1;
while (i<8 && words[i] == 0) {
++i; ++curGapLen;
}
if (curGapLen > longestGapLen) {
longestGapPos = curGapPos;
longestGapLen = curGapLen;
}
} else {
++i;
}
}
if (longestGapLen<=1)
longestGapPos = -1;
cp = buf;
for (i = 0; i < 8; ++i) {
if (words[i] == 0 && longestGapPos == i) {
if (i == 0)
*cp++ = ':';
*cp++ = ':';
while (i < 8 && words[i] == 0)
++i;
--i; /* to compensate for loop increment. */
} else {
tor_snprintf(cp, sizeof(buf)-(cp-buf), "%x", (unsigned)words[i]);
cp += strlen(cp);
if (i != 7)
*cp++ = ':';
}
}
*cp = '\0';
if ((strlen(buf) + 1) > len) /* +1 for \0 */
return NULL;
strlcpy(dst, buf, len);
return dst;
} else {
return NULL;
}
}
/** Given <b>af</b>==AF_INET or <b>af</b>==AF_INET6, and a string <b>src</b>
* encoding an IPv4 address or IPv6 address correspondingly, try to parse the
* address and store the result in <b>dst</b> (which must have space for a
* struct in_addr or a struct in6_addr, as appropriate). Return 1 on success,
* 0 on a bad parse, and -1 on a bad <b>af</b>.
*
* (Like inet_pton(af,src,dst) but works on platforms that don't have it: Tor
* sometimes needs to format ipv6 addresses even on platforms without ipv6
* support.) */
int
tor_inet_pton(int af, const char *src, void *dst)
{
if (af == AF_INET) {
return tor_inet_aton(src, dst);
} else if (af == AF_INET6) {
struct in6_addr *out = dst;
uint16_t words[8];
int gapPos = -1, i, setWords=0;
const char *dot = strchr(src, '.');
const char *eow; /* end of words. */
memset(words, 0xf8, sizeof(words));
if (dot == src)
return 0;
else if (!dot)
eow = src+strlen(src);
else {
unsigned byte1,byte2,byte3,byte4;
char more;
for (eow = dot-1; eow > src && TOR_ISDIGIT(*eow); --eow)
;
if (*eow != ':')
return 0;
++eow;
/* We use "scanf" because some platform inet_aton()s are too lax
* about IPv4 addresses of the form "1.2.3" */
if (tor_sscanf(eow, "%3u.%3u.%3u.%3u%c",
&byte1,&byte2,&byte3,&byte4,&more) != 4)
return 0;
if (byte1 > 255 || byte2 > 255 || byte3 > 255 || byte4 > 255)
return 0;
words[6] = (byte1<<8) | byte2;
words[7] = (byte3<<8) | byte4;
setWords += 2;
}
i = 0;
while (src < eow) {
if (i > 7)
return 0;
if (TOR_ISXDIGIT(*src)) {
char *next;
ssize_t len;
long r = strtol(src, &next, 16);
if (next == NULL || next == src) {
/* The 'next == src' error case can happen on versions of openbsd
* which treat "0xfoo" as an error, rather than as "0" followed by
* "xfoo". */
return 0;
}
len = *next == '\0' ? eow - src : next - src;
if (len > 4)
return 0;
if (len > 1 && !TOR_ISXDIGIT(src[1]))
return 0; /* 0x is not valid */
tor_assert(r >= 0);
tor_assert(r < 65536);
words[i++] = (uint16_t)r;
setWords++;
src = next;
if (*src != ':' && src != eow)
return 0;
++src;
} else if (*src == ':' && i > 0 && gapPos == -1) {
gapPos = i;
++src;
} else if (*src == ':' && i == 0 && src+1 < eow && src[1] == ':' &&
gapPos == -1) {
gapPos = i;
src += 2;
} else {
return 0;
}
}
if (setWords > 8 ||
(setWords == 8 && gapPos != -1) ||
(setWords < 8 && gapPos == -1))
return 0;
if (gapPos >= 0) {
int nToMove = setWords - (dot ? 2 : 0) - gapPos;
int gapLen = 8 - setWords;
tor_assert(nToMove >= 0);
memmove(&words[gapPos+gapLen], &words[gapPos],
sizeof(uint16_t)*nToMove);
memset(&words[gapPos], 0, sizeof(uint16_t)*gapLen);
}
for (i = 0; i < 8; ++i) {
out->s6_addr[2*i ] = words[i] >> 8;
out->s6_addr[2*i+1] = words[i] & 0xff;
}
return 1;
} else {
return -1;
}
}
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