socket_is_permitted

SFL
Version 2.11

`socket_is_permitted`

#include "sflsock.h"
Bool
socket_is_permitted (const char *address, const char *mask)

Synopsis

Compares the specified address with a mask and returns TRUE if the address matches the mask, or FALSE if it does not. The address is formatted as a string "xxx.xxx.xxx.xxx". The mask is formatted as zero or more patterns, delimited by whitespace or commas. A pattern is an address string, with zero or more of the last components replaced by '*'. The pattern may also be prefixed by '!' to indicate exclusion. This is an example of a mask: "127.0.0.1, 253.34.*, !253.35.*". This mask allows all addresses: "*". To get the string address for a remote socket, use socket_peer_address().

Source Code - (sflsock.c)

{
    char
        *addrptr,                       /*  Pointer into address             */
        *maskptr;                       /*  Pointer into mask                */
    Bool
        negate,                         /*  If !pattern                      */
        feedback = FALSE;               /*  False unless matched             */

    ASSERT (address);
    ASSERT (mask);

    maskptr = (char *) mask;
    while (*maskptr)
      {
        while (isspace (*maskptr) || *maskptr == ',')
            maskptr++;

        /*  Get negation if necessary                                        */
        if (*maskptr == '!')
          {
            negate = TRUE;
            maskptr++;
          }
        else
            negate = FALSE;

        /*  Compare pattern with address up to the end of the pattern        */
        for (addrptr = (char *) address; *addrptr; addrptr++)
          {
            if (*maskptr == '*')        /*  Matched address up to *          */
                return (!negate);       /*  So either accepted or failed     */
            else
            if (*maskptr == '\0')       /*  Did not match address            */
                return (negate);        /*    so fail unless negated         */
            else
            if (*addrptr != *maskptr)   /*  Some difference                  */
                break;                  /*    so stop comparing              */

            maskptr++;
          }
        if (*addrptr == '\0'            /*  Matched exact address?           */
        && (*maskptr == '\0' || isspace (*maskptr) || *maskptr == ','))
            return (!negate);           /*  Either accepted or failed        */

        until (*maskptr == '\0' || isspace (*maskptr) || *maskptr == ',')
            maskptr++;                  /*  Skip to end of this pattern      */
      }
    return (feedback);
}

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