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Cleanup of some of the new CIDR code: compiles but untested; Also: My first commit for a very long time

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git-svn-id: http://svn.inspircd.org/repository/trunk/inspircd@9979 e03df62e-2008-0410-955e-edbf42e46eb7
This commit is contained in:
om 2008-07-12 12:28:25 +00:00
parent ebb32bc0ed
commit ce53937c42
1 changed files with 58 additions and 60 deletions
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118
src/users.cpp
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@ -1120,87 +1120,85 @@ const char* User::GetCIDRMask(int range)
#ifdef SUPPORT_IP6LINKS
case AF_INET6:
{
/* unsigned char s6_addr[16]; */
struct in6_addr v6;
sockaddr_in6* sin;
int i, bytestozero, extrabits;
char buffer[40];
if(range > 128)
throw "CIDR mask width greater than address width (IPv6, 128 bit)";
/* Access the user's IP structure directly */
sin = (sockaddr_in6*)this->ip;
/* To create the CIDR mask we want to set all the bits after 'range' bits of the address
* to zero. This means the last (128 - range) bits of the address must be set to zero.
* Hence this number divided by 8 is the number of whole bytes from the end of the address
* which must be set to zero.
*/
bytestozero = (128 - range) / 8;
/* Some of the least significant bits of the next most significant byte may also have to
* be zeroed. The number of bits is the remainder of the above division.
*/
extrabits = (128 - range) % 8;
/* Populate our working struct with the parts of the user's IP which are required in the
* final CIDR mask. Set all the subsequent bytes to zero.
* (16 - bytestozero) is the number of bytes which must be populated with actual IP data.
*/
for(i = 0; i < (16 - bytestozero); i++)
{
printf("Error, range given (%d) larger than address length (128)\n", range);
return 0;
v6.s6_addr[i] = sin->sin6_addr.s6_addr[i];
}
if(inet_pton(AF_INET6, this->GetIPString(), &v6))
/* And zero all the remaining bytes in the IP. */
for(; i < 16; i++)
{
/* unsigned char s6_addr[16]; */
int i;
int bytestoblank;
int extrabits;
char buffer[64];
if(range > 0)
{
/* (128 - range) bits must be blanked, so ((128 - range) / 8) of the bytes, working backwards, must be blanked. */
bytestoblank = (128 - range) / 8;
/* ((128 - range) % 8) bits of the next byte must also be blanked. */
extrabits = (128 - range) % 8;
v6.s6_addr[15 - bytestoblank] = (v6.s6_addr[15 - bytestoblank] >> extrabits) << extrabits;
for(i = 0; i < bytestoblank; i++)
{
v6.s6_addr[15 - i] = 0;
}
}
else
{
for(i = 0; i < 15; i++)
{
v6.s6_addr[i] = 0;
}
}
sprintf(buf, "%s/%d\n", inet_ntop(AF_INET6, &v6, buffer, 64), range);
return buf;
}
else
{
throw "CIDR mask for v6 failed";
v6.s6_addr[i] = 0;
}
/* And finally, zero the extra bits required. */
v6.s6_addr[15 - bytestozero] = (v6.s6_addr[15 - bytestozero] >> extrabits) << extrabits;
sprintf(buf, "%s/%d\n", inet_ntop(AF_INET6, &v6, buffer, 40), range);
return buf;
}
break;
#endif
case AF_INET:
{
struct in_addr v4;
sockaddr_in* sin;
uint32_t temp;
char buffer[16];
if (range > 32)
throw "more than 32 bits on an ipv4 connection, can't do that..";
throw "CIDR mask width greater than address width (IPv4, 32 bit)";
if(inet_pton(AF_INET, this->GetIPString(), &v4))
/* Users already have a sockaddr* pointer (User::ip) which contains either a v4 or v6 structure */
sin = (sockaddr_in*)this->ip;
v4.s_addr = sin->sin_addr.s_addr;
/* (32 - range) is the number of bits we are *ignoring*. We shift this left and then right to wipe off these bits. */
if(range > 0)
{
char buffer[16];
uint32_t temp;
/* (32 - range) is the number of bits we are *ignoring*. We shift this left and then right to wipe off these bits. */
if(range > 0)
{
temp = ntohl(v4.s_addr);
temp = (temp >> (32 - range)) << (32 - range);
v4.s_addr = htonl(temp);
}
else
{
v4.s_addr = 0;
}
sprintf(buf, "%s/%d\n", inet_ntop(AF_INET, &v4, buffer, 16), range);
return buf;
temp = ntohl(v4.s_addr);
temp = (temp >> (32 - range)) << (32 - range);
v4.s_addr = htonl(temp);
}
else
{
throw "CIDR mask for v4 failed";
/* a range of zero would cause a 32 bit value to be shifted by 32 bits.
* this has undefined behaviour, but for CIDR purposes the resulting mask
* from a.b.c.d/0 is 0.0.0.0/0
*/
v4.s_addr = 0;
}
sprintf(buf, "%s/%d\n", inet_ntop(AF_INET, &v4, buffer, 16), range);
return buf;
}
break;
}