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#include "calc.h"
#include "itoa_lut.h"
#include <time.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <unistd.h>
int print_usage() {
printf("Invalid arguments:\n\tcalc <network/cidr> <ips per subnet>\n");
return 1;
}
uint32_t calc_netmask(unsigned int cidr) {
return UINT32_MAX << (32 - cidr);
}
uint32_t segments_to_ip(unsigned int segments[4]) {
return (segments[0] << 3*8) | (segments[1] << 2*8) | (segments[2] << 1*8) | (segments[3]);
}
uint32_t subnetmask_for_netspace(unsigned int desired_netspace) {
uint32_t start = UINT32_MAX;
// +1 because 2s complement
while (~start +1 < desired_netspace + 2) {
start = start << 1;
}
return start;
}
void write_ip(char **chunk_ptr, uint32_t ip) {
// local ptr so we don't have to deref every time
char *ptr = *chunk_ptr;
LutEntry e = itoa_lut[(ip >> 24) & 0xff];
WRITE_STR(ptr, e.chars, e.len)
ptr[0] = '.';
ptr += 1;
e = itoa_lut[(ip >> 16) & 0xff];
WRITE_STR(ptr, e.chars, e.len)
ptr[0] = '.';
ptr += 1;
e = itoa_lut[(ip >> 8) & 0xff];
WRITE_STR(ptr, e.chars, e.len)
ptr[0] = '.';
ptr += 1;
e = itoa_lut[ip & 0xff];
WRITE_STR(ptr, e.chars, e.len)
*chunk_ptr = ptr;
}
int main(int argc, char** argv) {
struct timespec start;
clock_gettime(CLOCK_MONOTONIC, &start);
unsigned int segments[4] = {0};
unsigned int cidr = 0;
unsigned int min_ips_per_subnet = 0;
// parse args
if (argc < 3) {
return print_usage();
}
if (sscanf(argv[1], "%u.%u.%u.%u/%u", &segments[0], &segments[1], &segments[2], &segments[3], &cidr) != 5) return print_usage();
if (sscanf(argv[2], "%u", &min_ips_per_subnet) != 1) return print_usage();
CalcRequest req = {
.network = segments_to_ip(segments), // fixed later
.netmask = calc_netmask(cidr),
.subnet_mask = subnetmask_for_netspace(min_ips_per_subnet),
.count = 0, // later
};
// User can provide any ip address, this converts it to the network address
req.network = req.network & req.netmask;
// +1 because 2s complement
const unsigned int ips_per_subnet = ~req.subnet_mask + 1;
req.count = (~req.netmask+1) / (ips_per_subnet);
FILE *out = fopen("file.json", "w");
if (out == NULL) {
perror("Failed to open output file:");
return errno;
}
fprintf(out, "[\n"); // file start
uint32_t offset = 0;
int i = 0;
char chunk[1024] = {0};
while (i<req.count) {
const uint32_t network = req.network + offset;
const uint32_t first = network + 1;
const uint32_t broadcast = first + ips_per_subnet - 2;
const uint32_t last = broadcast - 1;
offset += ips_per_subnet;
char* chunk_ptr = chunk;
WRITE_STR(chunk_ptr, "\t{\n\t\t\"Reseau\": \"", 16)
write_ip(&chunk_ptr, network);
WRITE_STR(chunk_ptr, "\",\n", 3)
WRITE_STR(chunk_ptr, "\t\t\"Premiere\": \"", 15)
write_ip(&chunk_ptr, first);
WRITE_STR(chunk_ptr, "\",\n", 3)
WRITE_STR(chunk_ptr, "\t\t\"Derniere\": \"", 15)
write_ip(&chunk_ptr, last);
WRITE_STR(chunk_ptr, "\",\n", 3)
WRITE_STR(chunk_ptr, "\t\t\"Broadcast\": \"", 16)
write_ip(&chunk_ptr, broadcast);
WRITE_STR(chunk_ptr, "\",\n", 3)
WRITE_STR(chunk_ptr, "\t\t\"Nbr\": \"", 10)
LutEntry e = itoa_lut[ips_per_subnet - 2];
WRITE_STR(chunk_ptr, e.chars, e.len);
if (i+1 == req.count) {
WRITE_STR(chunk_ptr, "\"\n\t}\n", 5)
}else {
WRITE_STR(chunk_ptr, "\"\n\t},\n", 6)
}
fwrite(chunk, sizeof(char), chunk_ptr - chunk, out);
i++;
}
fprintf(out, "]"); // file end
fflush(out);
sync();
fclose(out);
struct timespec end;
clock_gettime(CLOCK_MONOTONIC, &end);
printf("Time elapsed: %llu ms\n", (unsigned long long)((end.tv_sec - start.tv_sec) * 1e3 + (end.tv_nsec - start.tv_nsec) / 1e6));
return 0;
}
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