blob: 8eef03a863fe65b16d4bfb948727633ddcb6b897 [file] [log] [blame]
// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <algorithm>
#include <cstdlib>
#include <iterator>
#include <map>
#include <fcntl.h>
#include <netdb.h>
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include "net_util.h"
namespace net {
#ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
#define INET6_ADDRSTRLEN 46
#endif
bool ParseIPLiteralToNumber(const std::string& ip_literal,
IPAddressNumber* ip_number) {
char buf[sizeof(struct in6_addr)];
int size = sizeof(struct in_addr);
int mode = AF_INET;
if (ip_literal.find(':') != std::string::npos) {
mode = AF_INET6;
size = sizeof(struct in6_addr);
}
if (inet_pton(mode, ip_literal.c_str(), buf) != 1) {
return false;
}
ip_number->resize(size);
for (int i = 0; i < size; i++) {
(*ip_number)[i] = buf[i];
}
return true;
}
IPAddressNumber ConvertIPv4NumberToIPv6Number(
const IPAddressNumber& ipv4_number) {
// IPv4-mapped addresses are formed by:
// <80 bits of zeros> + <16 bits of ones> + <32-bit IPv4 address>.
IPAddressNumber ipv6_number;
ipv6_number.reserve(16);
ipv6_number.insert(ipv6_number.end(), 10, 0);
ipv6_number.push_back(0xFF);
ipv6_number.push_back(0xFF);
ipv6_number.insert(ipv6_number.end(), ipv4_number.begin(), ipv4_number.end());
return ipv6_number;
}
bool ParseCIDRBlock(const std::string& cidr_literal,
IPAddressNumber* ip_number,
size_t* prefix_length_in_bits) {
// We expect CIDR notation to match one of these two templates:
// <IPv4-literal> "/" <number of bits>
// <IPv6-literal> "/" <number of bits>
std::vector<std::string> parts;
size_t split = cidr_literal.find('/');
if (split == std::string::npos)
return false;
parts.push_back(cidr_literal.substr(0, split));
parts.push_back(cidr_literal.substr(split + 1));
if (parts[1].find('/') != std::string::npos)
return false;
// Parse the IP address.
if (!ParseIPLiteralToNumber(parts[0], ip_number))
return false;
// Parse the prefix length.
int number_of_bits = atoi(parts[1].c_str());
// Make sure the prefix length is in a valid range.
if (number_of_bits < 0 ||
number_of_bits > static_cast<int>(ip_number->size() * 8))
return false;
*prefix_length_in_bits = static_cast<size_t>(number_of_bits);
return true;
}
bool IPNumberMatchesPrefix(const IPAddressNumber& ip_number,
const IPAddressNumber& ip_prefix,
size_t prefix_length_in_bits) {
// Both the input IP address and the prefix IP address should be
// either IPv4 or IPv6.
// In case we have an IPv6 / IPv4 mismatch, convert the IPv4 addresses to
// IPv6 addresses in order to do the comparison.
if (ip_number.size() != ip_prefix.size()) {
if (ip_number.size() == 4) {
return IPNumberMatchesPrefix(ConvertIPv4NumberToIPv6Number(ip_number),
ip_prefix, prefix_length_in_bits);
}
return IPNumberMatchesPrefix(ip_number,
ConvertIPv4NumberToIPv6Number(ip_prefix),
96 + prefix_length_in_bits);
}
// Otherwise we are comparing two IPv4 addresses, or two IPv6 addresses.
// Compare all the bytes that fall entirely within the prefix.
int num_entire_bytes_in_prefix = prefix_length_in_bits / 8;
for (int i = 0; i < num_entire_bytes_in_prefix; ++i) {
if (ip_number[i] != ip_prefix[i])
return false;
}
// In case the prefix was not a multiple of 8, there will be 1 byte
// which is only partially masked.
int remaining_bits = prefix_length_in_bits % 8;
if (remaining_bits != 0) {
unsigned char mask = 0xFF << (8 - remaining_bits);
int i = num_entire_bytes_in_prefix;
if ((ip_number[i] & mask) != (ip_prefix[i] & mask))
return false;
}
return true;
}
} // namespace net