pm_Checker:: ip_address Method

Checks whether the specified IP address satisfies the selected validation rule and IP format.

Syntax

public static function ip_address ($str, $valid, $valid_formats)

Parameters

str

      A string value that specifies the IP address to check.

valid

      A string value that specifies the validation rule to apply. Is set to IP_ADDRESS_ANY by default. The following validation rules are available:

• IP_ADDRESS_ANY allows the use of all rules available.
• IP_ADDRESS_BLOCK checks whether the IP address presents an address block (a group of network addresses) rather than a certain address.
• IP_ADDRESS_NETMASK checks whether the given IP address is an individual IP address with a mask.
• IP_ADDRESS selects the rule that checks whether the given IP mask specifies the whole IP address.

valid_formats

      A string value that specifies the allowed IP address format. Is set to IP_ADDRESS_ANY_FORMAT by default. The following formats are available:

• IP_ADDRESS_MASK_FORMAT allows the IP address with a wildcard ('*').
• IP_ADDRESS_BLOCK_FORMAT allows the IP address in the CIDR notation (xxx.xxx.xxx.xxx/n where n is a number of '1' network bits in the mask).
• IP_ADDRESS_NETMASK_FORMAT allows the IP address with a network mask in the format as follows: xxx.xxx.xxx.xxx/xxx.xxx.xxx.xxx (<IP_address>/<IP_mask>).
• IP_ADDRESS _FORMAT allows a typical IP address in the dotted-decimal notation, i.e. xxx.xxx.xxx.xxx.
• IP_ADDRESS_ANY_FORMAT allows the use of any above format.

Returns

A boolean which is true if the checked IP address satisfies the validation rule(s) applied and is formatted as specified by the valid_formats constant. Otherwise returns false.

Remarks

This function validates the passed in IP address based on two constants that specify the format of the IP address and the validation rule(s) that should be applied to discover whether the IP address in focus really matches this format.

Here is the table of the admissible combinations of the validation rules and formats:

The validation rule(s) to apply is (are) specified in the valid parameter. They work as follows:

• IP_ADDRESS_BLOCK checks whether the IP address specifies a group of IP addresses (i.e. whether the IP address presents an address block). This rule requires the use of a masked IP address format, and the requirement is that the host bits are set to '0'. E.g. 123.123.0.0/16 is a range of addresses, but 123.123.0.1/16 is a particular IP address in a class B network.
• IP_ADDRESS_NETMASK checks whether the IP address is an individual masked IP address. The rule succeeds if the IP mask specifies the entire IP address, e.g. 123.123.123.1/32 or 123.123.123.1/255.255.255.255. The rule fails if the IP address has '0' bits in its host part, e.g. 123.123.0.0/16, or if it has all '1' bits in the host part (a broadcast address), e.g. 123.123.123.255/255.255.255.0.
• IP_ADDRESS checks whether the IP address in focus is a non-masked individual IP address. E.g. 123.123.123.123.
• IP_ADDRESS_ANY indicates to the function that all the rules should be applied to the IP address by after another until any of them succeeds. If none of the above rules succeeds, this rule fails.

The valid_formats parameter informs the function what IP address format is validated.

• IP_ADDRESS_MASK_FORMAT means that an IP address with a wildcard (*) is expected. A wildcard is allowed in place of any block, except the first one. E.g. 123.123.123.*.
• IP_ADDRESS_BLOCK_FORMAT means that the IP address presents a group of addresses and the CIDR notation is used to indicate the network size, e.g. 123.123.0.0/16 (16 leftmost bits are the network ones). Or this format can be applied to specify a particular IP address and to provide it with the information about the network size, e.g. 123.123.123.123/24 (the host part is the rightmost block of 8 bits). If used to specify a particular non-masked IP address, this format should look as follows: 123.123.123.123/32.
• IP_ADDRESS_NETMASK_FORMAT is a standard dotted-decimal notation with a mask (xxx.xxx.xxx.xxx/xxx.xxx.xxx.xxx). The first part specifies the IP address, the second part presents a mask applied to this address. This format can be used to specify a group of IP addresses (address block), e.g. 123.123.123.0/255.255.255.0, a masked IP address, e.g. 123.123.123.123/255.255.255.0, or a non-masked IP address, e.g. 123.123.123.123/255.255.255.255.
• IP_ADDRESS _FORMAT is a non-masked dotted decimal format (xxx.xxx.xxx.xxx). It is used to specify an individual IP address, no information about the network size provided. E.g. 123.123.123.1.
• IP_ADDRESS_ANY_FORMAT means that the format check will be successful if the IP address matches any of the above formats.