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|
/* +------------------------------------+
* | Inspire Internet Relay Chat Daemon |
* +------------------------------------+
*
* InspIRCd: (C) 2002-2008 InspIRCd Development Team
* See: http://www.inspircd.org/wiki/index.php/Credits
*
* This program is free but copyrighted software; see
* the file COPYING for details.
*
* ---------------------------------------------------
*/
/* $Core */
#include "inspircd.h"
/* Used when comparing CIDR masks for the modulus bits left over.
* A lot of ircd's seem to do this:
* ((-1) << (8 - (mask % 8)))
* But imho, it sucks in comparison to a nice neat lookup table.
*/
const unsigned char inverted_bits[8] = { 0x00, /* 00000000 - 0 bits - never actually used */
0x80, /* 10000000 - 1 bits */
0xC0, /* 11000000 - 2 bits */
0xE0, /* 11100000 - 3 bits */
0xF0, /* 11110000 - 4 bits */
0xF8, /* 11111000 - 5 bits */
0xFC, /* 11111100 - 6 bits */
0xFE /* 11111110 - 7 bits */
};
/* Match raw bytes using CIDR bit matching, used by higher level MatchCIDR() */
bool irc::sockets::MatchCIDRBits(const unsigned char* address, const unsigned char* mask, unsigned int mask_bits)
{
unsigned int divisor = mask_bits / 8; /* Number of whole bytes in the mask */
unsigned int modulus = mask_bits % 8; /* Remaining bits in the mask after whole bytes are dealt with */
/* First (this is faster) compare the odd bits with logic ops */
if (modulus)
if ((address[divisor] & inverted_bits[modulus]) != (mask[divisor] & inverted_bits[modulus]))
/* If they dont match, return false */
return false;
/* Secondly (this is slower) compare the whole bytes */
if (memcmp(address, mask, divisor))
return false;
/* The address matches the mask, to mask_bits bits of mask */
return true;
}
/* Match CIDR, but dont attempt to match() against leading *!*@ sections */
bool irc::sockets::MatchCIDR(const std::string &address, const std::string &cidr_mask)
{
return MatchCIDR(address, cidr_mask, false);
}
/* Match CIDR strings, e.g. 127.0.0.1 to 127.0.0.0/8 or 3ffe:1:5:6::8 to 3ffe:1::0/32
* If you have a lot of hosts to match, youre probably better off building your mask once
* and then using the lower level MatchCIDRBits directly.
*
* This will also attempt to match any leading usernames or nicknames on the mask, using
* match(), when match_with_username is true.
*/
bool irc::sockets::MatchCIDR(const std::string &address, const std::string &cidr_mask, bool match_with_username)
{
unsigned char addr_raw[16];
unsigned char mask_raw[16];
unsigned int bits = 0;
std::string address_copy;
std::string cidr_copy;
/* The caller is trying to match ident@<mask>/bits.
* Chop off the ident@ portion, use match() on it
* seperately.
*/
if (match_with_username)
{
/* Use strchr not strrchr, because its going to be nearer to the left */
std::string::size_type username_mask_pos = cidr_mask.rfind('@');
std::string::size_type username_addr_pos = address.rfind('@');
/* Both strings have an @ symbol in them */
if (username_mask_pos != std::string::npos && username_addr_pos != std::string::npos)
{
/* Try and match() the strings before the @
* symbols, and recursively call MatchCIDR without
* username matching enabled to match the host part.
*/
return (InspIRCd::Match(address.substr(0, username_addr_pos), cidr_mask.substr(0, username_mask_pos), NULL) &&
MatchCIDR(address.substr(username_addr_pos + 1), cidr_mask.substr(username_mask_pos + 1), false));
}
else
{
address_copy = address.substr(username_addr_pos + 1);
cidr_copy = cidr_mask.substr(username_mask_pos + 1);
}
}
else
{
address_copy.assign(address);
cidr_copy.assign(cidr_mask);
}
in_addr address_in4;
in_addr mask_in4;
std::string::size_type bits_chars = cidr_copy.rfind('/');
if (bits_chars != std::string::npos)
{
bits = atoi(cidr_copy.substr(bits_chars + 1).c_str());
cidr_copy.erase(bits_chars, cidr_copy.length() - bits_chars);
}
else
{
/* No 'number of bits' field! */
return false;
}
#ifdef SUPPORT_IP6LINKS
in6_addr address_in6;
in6_addr mask_in6;
if (inet_pton(AF_INET6, address_copy.c_str(), &address_in6) > 0)
{
if (inet_pton(AF_INET6, cidr_copy.c_str(), &mask_in6) > 0)
{
memcpy(&addr_raw, &address_in6.s6_addr, 16);
memcpy(&mask_raw, &mask_in6.s6_addr, 16);
if (bits > 128)
bits = 128;
}
else
{
/* The address was valid ipv6, but the mask
* that goes with it wasnt.
*/
return false;
}
}
else
#endif
if (inet_pton(AF_INET, address_copy.c_str(), &address_in4) > 0)
{
if (inet_pton(AF_INET, cidr_copy.c_str(), &mask_in4) > 0)
{
memcpy(&addr_raw, &address_in4.s_addr, 4);
memcpy(&mask_raw, &mask_in4.s_addr, 4);
if (bits > 32)
bits = 32;
}
else
{
/* The address was valid ipv4,
* but the mask that went with it wasnt.
*/
return false;
}
}
else
{
/* The address was neither ipv4 or ipv6 */
return false;
}
/* Low-level-match the bits in the raw data */
return MatchCIDRBits(addr_raw, mask_raw, bits);
}
|
