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Diffstat (limited to 'src/cidr.cpp')
| -rw-r--r-- | src/cidr.cpp | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/src/cidr.cpp b/src/cidr.cpp new file mode 100644 index 000000000..1288d269b --- /dev/null +++ b/src/cidr.cpp @@ -0,0 +1,204 @@ +/* +------------------------------------+ + * | 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: libIRCDcidr */ + +#include "inspircd.h" +#include "wildcard.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(unsigned char* address, 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 char* address, const char* 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 char* address, const char* cidr_mask, bool match_with_username) +{ + unsigned char addr_raw[16]; + unsigned char mask_raw[16]; + unsigned int bits = 0; + char* mask = NULL; + + /* The caller is trying to match ident@<mask>/bits. + * Chop off the ident@ portion, use match() on it + * seperately. + */ + if (match_with_username) + { + /* Duplicate the strings, and try to find the position + * of the @ symbol in each + */ + char* address_dupe = strdup(address); + char* cidr_dupe = strdup(cidr_mask); + + /* Use strchr not strrchr, because its going to be nearer to the left */ + char* username_mask_pos = strrchr(cidr_dupe, '@'); + char* username_addr_pos = strrchr(address_dupe, '@'); + + /* Both strings have an @ symbol in them */ + if (username_mask_pos && username_addr_pos) + { + /* Zero out the location of the @ symbol */ + *username_mask_pos = *username_addr_pos = 0; + + /* Try and match() the strings before the @ + * symbols, and recursively call MatchCIDR without + * username matching enabled to match the host part. + */ + bool result = (match(address_dupe, cidr_dupe) && MatchCIDR(username_addr_pos + 1, username_mask_pos + 1, false)); + + /* Free the stuff we created */ + free(address_dupe); + free(cidr_dupe); + + /* Return a result */ + return result; + } + else + { + /* One or both didnt have an @ in, + * just match as CIDR + */ + free(address_dupe); + free(cidr_dupe); + mask = strdup(cidr_mask); + } + } + else + { + /* Make a copy of the cidr mask string, + * we're going to change it + */ + mask = strdup(cidr_mask); + } + + in_addr address_in4; + in_addr mask_in4; + + + /* Use strrchr for this, its nearer to the right */ + char* bits_chars = strrchr(mask,'/'); + + if (bits_chars) + { + bits = atoi(bits_chars + 1); + *bits_chars = 0; + } + else + { + /* No 'number of bits' field! */ + free(mask); + return false; + } + +#ifdef SUPPORT_IP6LINKS + in6_addr address_in6; + in6_addr mask_in6; + + if (inet_pton(AF_INET6, address, &address_in6) > 0) + { + if (inet_pton(AF_INET6, mask, &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. + */ + free(mask); + return false; + } + } + else +#endif + if (inet_pton(AF_INET, address, &address_in4) > 0) + { + if (inet_pton(AF_INET, mask, &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. + */ + free(mask); + return false; + } + } + else + { + /* The address was neither ipv4 or ipv6 */ + free(mask); + return false; + } + + /* Low-level-match the bits in the raw data */ + free(mask); + return MatchCIDRBits(addr_raw, mask_raw, bits); +} + + + |