cider/parse.c

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>

#include "parse.h"

/*
 * Assumes full string is given in "start" argument, which is then modified.
 * Does not do any validation, inet_network can do that later.
 * Need "end" to be a double-pointer so we can modify the original pointer.
 */
int split_range(char *start, char **end) {
    bool range_delim_found = false;
    char *p = start;
    while(*p != '\0') {
        if(range_delim_found) {
            *end = p;
            return 0;
        }
        if(*p == '-') {
            *p = '\0';
            range_delim_found = true;
        }
        ++p;
    }
    // Never found delimiter ...
    return 1;
}

void deaggregate(in_addr_t start, in_addr_t end) {
    in_addr_t base = start;
    while(base <= end) {
        int step = 0;
        while((base | (1 << step)) != base) { // Look for the first zero from the right
            if((base | UINT32_MAX >> (31 - step)) > end) {
                break;
            }
            ++step;
        }
        struct in_addr prefix;
        prefix.s_addr = htonl(base);
        printf("%s/%d\n", inet_ntoa(prefix), 32 - step);
        base += 1 << step;
    }
}