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<?php// This file is part of Moodle - http://moodle.org///// Moodle is free software: you can redistribute it and/or modify// it under the terms of the GNU General Public License as published by// the Free Software Foundation, either version 3 of the License, or// (at your option) any later version.//// Moodle is distributed in the hope that it will be useful,// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the// GNU General Public License for more details.//// You should have received a copy of the GNU General Public License// along with Moodle. If not, see <http://www.gnu.org/licenses/>./*** Contains a simple class providing some useful internet protocol-related functions.** @package core* @copyright 2016 Jake Dallimore* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later* @author Jake Dallimore <jrhdallimore@gmail.com>*/namespace core;defined('MOODLE_INTERNAL') || exit();/*** Static helper class providing some useful internet-protocol-related functions.** @package core* @copyright 2016 Jake Dallimore* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later* @author Jake Dallimore <jrhdallimore@gmail.com>*/final class ip_utils {/*** Syntax checking for domain names, including fully qualified domain names.** This function does not verify the existence of the domain name. It only verifies syntactic correctness.* This is based on RFC1034/1035 and does not provide support for validation of internationalised domain names (IDNs).* All IDNs must be prior-converted to their ascii-compatible encoding before being passed to this function.** @param string $domainname the input string to check.* @return bool true if the string has valid syntax, false otherwise.*/public static function is_domain_name($domainname) {if (!is_string($domainname)) {return false;}// Usually the trailing dot (null label) is omitted, but is valid if supplied. We'll just remove it and validate as normal.$domainname = rtrim($domainname, '.');// The entire name cannot exceed 253 ascii characters (255 octets, less the leading label-length byte and null label byte).if (strlen($domainname) > 253) {return false;}// Tertiary domain labels can have 63 octets max, and must not have begin or end with a hyphen.// The TLD label cannot begin with a number, but otherwise, is only loosely restricted here (TLD list is not checked).$domaintertiary = '([a-zA-Z0-9](([a-zA-Z0-9-]{0,61})[a-zA-Z0-9])?\.)*';$domaintoplevel = '([a-zA-Z](([a-zA-Z0-9-]*)[a-zA-Z0-9])?)';$address = '(' . $domaintertiary . $domaintoplevel . ')';$regexp = '#^' . $address . '$#i'; // Case insensitive matching.return preg_match($regexp, $domainname, $match) == true; // False for error, 0 for no match - we treat the same.}/*** Checks whether the input string is a valid wildcard domain matching pattern.** A domain matching pattern is essentially a domain name with a single, leading wildcard (*) label, and at least one other* label. The wildcard label is considered to match at least one label at or above (to the left of) its position in the string,* but will not match the trailing domain (everything to its right).** The string must be dot-separated, and the whole pattern must follow the domain name syntax rules defined in RFC1034/1035.* Namely, the character type (ascii), total-length (253) and label-length (63) restrictions. This function only confirms* syntactic correctness. It does not check for the existence of the domain/subdomains.** For example, the string '*.example.com' is a pattern deemed to match any direct subdomain of* example.com (such as test.example.com), any higher level subdomains (e.g. another.test.example.com) but will not match* the 'example.com' domain itself.** @param string $pattern the string to check.* @return bool true if the input string is a valid domain wildcard matching pattern, false otherwise.*/public static function is_domain_matching_pattern($pattern) {if (!is_string($pattern)) {return false;}// Usually the trailing dot (null label) is omitted, but is valid if supplied. We'll just remove it and validate as normal.$pattern = rtrim($pattern, '.');// The entire name cannot exceed 253 ascii characters (255 octets, less the leading label-length byte and null label byte).if (strlen($pattern) > 253) {return false;}// A valid pattern must left-positioned wildcard symbol (*).// Tertiary domain labels can have 63 octets max, and must not have begin or end with a hyphen.// The TLD label cannot begin with a number, but otherwise, is only loosely restricted here (TLD list is not checked).$wildcard = '((\*)\.){1}';$domaintertiary = '([a-zA-Z0-9](([a-zA-Z0-9-]{0,61})[a-zA-Z0-9])?\.)*';$domaintoplevel = '([a-zA-Z](([a-zA-Z0-9-]*)[a-zA-Z0-9])?)';$address = '(' . $wildcard . $domaintertiary . $domaintoplevel . ')';$regexp = '#^' . $address . '$#i'; // Case insensitive matching.return preg_match($regexp, $pattern, $match) == true; // False for error, 0 for no match - we treat the same.}/*** Syntax validation for IP addresses, supporting both IPv4 and Ipv6 formats.** @param string $address the address to check.* @return bool true if the address is a valid IPv4 of IPv6 address, false otherwise.*/public static function is_ip_address($address) {return filter_var($address, FILTER_VALIDATE_IP) !== false;}/*** Syntax validation for IPv4 addresses.** @param string $address the address to check.* @return bool true if the address is a valid IPv4 address, false otherwise.*/public static function is_ipv4_address($address) {return filter_var($address, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4) !== false;}/*** Syntax checking for IPv4 address ranges.* Supports CIDR notation and last-group ranges.* Eg. 127.0.0.0/24 or 127.0.0.80-255** @param string $addressrange the address range to check.* @return bool true if the string is a valid range representation, false otherwise.*/public static function is_ipv4_range($addressrange) {// Check CIDR notation.if (preg_match('#^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\/(\d{1,2})$#', $addressrange, $match)) {$address = "{$match[1]}.{$match[2]}.{$match[3]}.{$match[4]}";return self::is_ipv4_address($address) && $match[5] <= 32;}// Check last-group notation.if (preg_match('#^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})-(\d{1,3})$#', $addressrange, $match)) {$address = "{$match[1]}.{$match[2]}.{$match[3]}.{$match[4]}";return self::is_ipv4_address($address) && $match[5] <= 255 && $match[5] >= $match[4];}return false;}/*** Syntax validation for IPv6 addresses.* This function does not check whether the address is assigned, only its syntactical correctness.** @param string $address the address to check.* @return bool true if the address is a valid IPv6 address, false otherwise.*/public static function is_ipv6_address($address) {return filter_var($address, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) !== false;}/*** Syntax validation for IPv6 address ranges.* Supports CIDR notation and last-group ranges.* Eg. fe80::d98c/64 or fe80::d98c-ffee** @param string $addressrange the IPv6 address range to check.* @return bool true if the string is a valid range representation, false otherwise.*/public static function is_ipv6_range($addressrange) {// Check CIDR notation.$ipv6parts = explode('/', $addressrange);if (count($ipv6parts) == 2) {$range = (int)$ipv6parts[1];return self::is_ipv6_address($ipv6parts[0]) && (string)$range === $ipv6parts[1] && $range >= 0 && $range <= 128;}// Check last-group notation.$ipv6parts = explode('-', $addressrange);if (count($ipv6parts) == 2) {$addressparts = explode(':', $ipv6parts[0]);$rangestart = $addressparts[count($addressparts) - 1];$rangeend = $ipv6parts[1];return self::is_ipv6_address($ipv6parts[0]) && ctype_xdigit($rangestart) && ctype_xdigit($rangeend)&& strlen($rangeend) <= 4 && strlen($rangestart) <= 4 && hexdec($rangeend) >= hexdec($rangestart);}return false;}/*** Checks the domain name against a list of allowed domains. The list of allowed domains may use wildcards* that match {@see is_domain_matching_pattern()}. Domains are compared in a case-insensitive manner** @param string $domain Domain address* @param array $alloweddomains An array of allowed domains.* @return boolean True if the domain matches one of the entries in the allowed domains list.*/public static function is_domain_in_allowed_list($domain, $alloweddomains) {if (!self::is_domain_name($domain)) {return false;}foreach ($alloweddomains as $alloweddomain) {if (strpos($alloweddomain, '*') !== false) {if (!self::is_domain_matching_pattern($alloweddomain)) {continue;}// Use of wildcard for possible subdomains.$escapeperiods = str_replace('.', '\.', $alloweddomain);$replacewildcard = str_replace('*', '.*', $escapeperiods);$ultimatepattern = '/' . $replacewildcard . '$/i';if (preg_match($ultimatepattern, $domain)) {return true;}} else {if (!self::is_domain_name($alloweddomain)) {continue;}// Strict domain setting.if (strcasecmp($domain, $alloweddomain) === 0) {return true;}}}return false;}/*** Is an ip in a given list of subnets?** @param string $ip - the IP to test against the list* @param string $list - the list of IP subnets* @param string $delim a delimiter of the list* @return bool*/public static function is_ip_in_subnet_list($ip, $list, $delim = "\n") {$list = explode($delim, $list);foreach ($list as $line) {$tokens = explode('#', $line);$subnet = trim($tokens[0]);if (address_in_subnet($ip, $subnet)) {return true;}}return false;}/*** Return IP address for given hostname, or null on failure** @param string $hostname* @return string|null*/public static function get_ip_address(string $hostname): ?string {if (self::is_domain_name($hostname)) {$address = gethostbyname($hostname);// If address is different from hostname, we have success.if (strcasecmp($address, $hostname) !== 0) {return $address;}}return null;}}