+unsigned short port = 2007;
+
+struct in_addr *destinations = NULL;
+unsigned num_destinations = 0;
+unsigned room_destinations = 0;
+
+struct in_addr *sources = NULL;
+unsigned num_sources = 0;
+unsigned room_sources = 0;
+
+const static struct option longopts[] = {
+ { "source-file", required_argument, NULL, 's' },
+ { "destination-file", required_argument, NULL, 'd' },
+ { "port", required_argument, NULL, 'p' },
+ { NULL, 0, NULL, 0 }
+};
+
+void read_ip_list(char *filename, struct in_addr **addr_list, unsigned *num, unsigned *room)
+{
+ char buf[256];
+ FILE *in = fopen(filename, "r");
+ if (in == NULL) {
+ perror(filename);
+ exit(1);
+ }
+
+ for ( ;; ) {
+ char *ptr;
+ struct in_addr addr;
+ struct hostent *he;
+
+ if (fgets(buf, 256, in) == NULL)
+ break;
+
+ ptr = strchr(buf, '\n');
+ if (ptr != NULL)
+ *ptr = 0;
+
+ ptr = strchr(buf, '\r');
+ if (ptr != NULL)
+ *ptr = 0;
+
+ ptr = buf + strspn(buf, " \t");
+
+ if (ptr[0] == '#' || ptr[0] == 0)
+ continue;
+
+ he = gethostbyname(ptr);
+ if (he == NULL) {
+ perror(ptr);
+ exit(1);
+ }
+
+ // just pick the first for now
+ memcpy(&addr.s_addr, he->h_addr_list[0], sizeof(addr.s_addr));
+
+ if (*num >= *room) {
+ if (*room == 0) {
+ *room = 16;
+ } else {
+ *room <<= 1;
+ }
+ *addr_list = (struct in_addr *)realloc(*addr_list, *room * sizeof(struct in_addr));
+ }
+
+ (*addr_list)[*num] = addr;
+ ++*num;
+ }
+
+ fclose(in);
+}
+
+void parse_options(int argc, char **argv)
+{
+ int option_index = 0;
+
+ for ( ;; ) {
+ int c = getopt_long(argc, argv, "s:d:p:", longopts, &option_index);
+ switch (c) {
+ case 's':
+ read_ip_list(optarg, &sources, &num_sources, &room_sources);
+ break;
+ case 'd':
+ read_ip_list(optarg, &destinations, &num_destinations, &room_destinations);
+ break;
+ case 'p':
+ port = atoi(optarg);
+ break;
+ case -1:
+ return; // end of argument list
+ default:
+ fprintf(stderr, "Invalid option\n");
+ exit(1);
+ }
+ }
+}
+