fix: exit when error in parsing occured

src/main.c

@@ -92,7 +92,8 @@ int main(int ac, char **av)
     (void) ac;
     struct setting settings;
 
-    get_setting(av + 1, &settings);
+    if (get_setting(av + 1, &settings))
+        return 1;
 
     size_t payload_size = 20;
     size_t packet_size = sizeof(struct icmphdr) + payload_size;
@@ -101,7 +102,6 @@ int main(int ac, char **av)
 
     if (dns_lookup(&settings.dest))
         return 5;
-
     
     settings.dest.ip.sin_family = AF_INET;
     settings.dest.ip.sin_port = htons(0);