tools.c

#include "tools.h"
#include "logger.h"

#include <string.h>
#include <getopt.h>
#include <stdio.h>
#include <netinet/in.h>
#include <stdlib.h>

ATTR_NONNULL_ALL void addr_add(struct in_addr* subnet, struct in_addr* result, int add) {
  struct in_addr addr;
  memcpy(&addr, subnet, sizeof(struct in_addr));
  addr.s_addr = ntohl(addr.s_addr);
  addr.s_addr += (in_addr_t)add;
  addr.s_addr = htonl(addr.s_addr);
  memcpy(result, &addr, sizeof(struct in_addr));
}

dhcp_option* parse_option() {

  //size_t optlen = strlen(optarg);

  char* len_s = strchr(optarg, ':');

  if (!len_s) {
    ERROR("parse_option(...): Malformed dhcp option '%s'\n", optarg);
    exit(1);
  }

  len_s++[0] = '\0';

  char* payload_s = strchr(len_s, ':');

  if (!payload_s) {
    ERROR("parse_option(...): Malformed dhcp option '%s'\n", optarg);
    exit(1);
  }

  payload_s++[0] = '\0';

  uint8_t len = (uint8_t)atoi(len_s);
  uint8_t code = (uint8_t)atoi(optarg);

  dhcp_option* option = (dhcp_option*) malloc(sizeof(dhcp_option));

  if (!option) {
    ERROR("parse_option(...): Failed to allocate memory for dhcp option '%s'\n", optarg);
    exit(1);
  }

  option->code = code;
  option->len = len;
  option->payload = calloc(len, 1);

  if (!option->payload) {
    ERROR("parse_option(...): Failed to allocate memory for dhcp option payload '%s'\n", optarg);
    free(option);
    exit(1);
  }

  for (int i = 0 ; i < len; i++) {
    char* next_payload_s = strchr(payload_s, '.');

    if (!next_payload_s && (i + 1 < len)) {
      ERROR("parse_option(...): Malformed dhcp option '%s': too little payload\n", optarg);
      exit(1);
    }

    if (i + 1 < len) {
      next_payload_s++[0] = '\0';
    }

    uint8_t payload = (uint8_t)strtoul(payload_s, NULL, 0);
    option->payload[i] = payload;
    payload_s = next_payload_s;
  }

  return option;
}

ATTR_NONNULL_ALL char* hwaddr2c(uint8_t* hwaddr) {
  char* str = calloc(18, 1);

  if (!str) {
    FATAL("hwaddr2c(...): Failed to allocate buffer.\n");
    return NULL;
  }

  snprintf(str, 18, "%02X:%02X:%02X:%02X:%02X:%02X",
    hwaddr[0], hwaddr[1], hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]);

  return str;
}