/**
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* A basic dns benchmark testing program
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* Tests servers in parallel so reasonably fast
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* Tried to only use POSIX functions to ensure cross platform compatibility
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**/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <time.h>
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#include <pthread.h>
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#include "dns.h"
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#include "servers.h"
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#include "slist.h"
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#define NUM_TESTS 10
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int test_dns(void);
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void *test_server(void *in);
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void *print_progress(void *in);
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// All global variables as passing to threads in structs caused corruption
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// Variables are only modified before threads are created and as such are thread-safe
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// tests_done is modified to provide a rough count of number of tests being completed for progress measurement
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int tests_done = 0, num_tests = NUM_TESTS, num_servers = NUM_DNS, num_hosts = 0;
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struct hosts_list *hosts = NULL;
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struct dns_list *servers = NULL;
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int main(int argc, char** argv)
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{
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int option, added_hosts = 0;
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while((option = getopt(argc, argv, "s:a:t:n:h")) != -1) {
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switch (option) {
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case 's': //server to use
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add_dns_server(&servers, optarg);
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num_servers++;
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break;
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case 'a': //hostname to search
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add_hosts_server(&hosts, optarg);
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added_hosts++;
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break;
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case 't': //set number of hosts to test
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num_hosts = atoi(optarg);
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break;
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case 'n': //number of tests to perform
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num_tests = atoi(optarg);
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break;
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case '?':
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case 'h':
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default:
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printf("Usage: %s [options]\n", argv[0]);
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printf("Options:\n");
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printf("\t-s <server>\tadd a DNS server to be tested\n");
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printf("\t-a <hostname>\tadd a hostname to be tested\n");
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printf("\t-t <number>\tspecify the number of hostnames to be tested, capped at 50 + number manually added\n\t\t\tdefaults to test all available\n");
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printf("\t-n <number>\tspecify the number of tests to perform on each hostname\n\t\t\tdefaults to 10\n");
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printf("\t-h\t\tShow this help\n");
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free_dns_list(&servers);
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free_hosts_list(&hosts);
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exit(1);
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}
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}
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if (num_hosts == 0 || num_hosts > NUM_HOSTNAMES+added_hosts) {
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num_hosts = NUM_HOSTNAMES + added_hosts;
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}
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for (int i = added_hosts; i < num_hosts; i++) {
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add_hosts_server(&hosts, (char*)HOSTNAMES[i-added_hosts]);
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}
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for (int i = 0; i < NUM_DNS; i++) {
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add_dns_server(&servers, (char*)DNS_SERVERS[i]);
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}
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test_dns();
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sort_servers(&servers);
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print_servers(servers);
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free_dns_list(&servers);
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free_hosts_list(&hosts);
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return 0;
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}
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// Test each dns server individually
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// Each test runs in its own thread and results are written to the respective dns_list
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int test_dns(void)
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{
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struct dns_list *curr = servers;
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int i = 0;
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pthread_t *threads = malloc(num_servers*sizeof(pthread_t));
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pthread_t progress;
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pthread_create(&progress, NULL, print_progress, NULL);
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while (curr) {
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pthread_create(&threads[i], NULL, test_server, (void*)curr);
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curr = curr->next;
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i++;
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}
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for (int i = 0; i < num_servers; i++) {
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pthread_join(threads[i], NULL);
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}
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pthread_cancel(progress);
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printf("\r100.00%% done\n");
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free(threads);
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return 0;
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}
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// Tests an individual dns server with all the hostnames configured
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void *test_server(void *in)
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{
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unsigned long long avg_nsec = 0;
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struct dns_list *dns = (struct dns_list *)in;
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dns->time.tv_sec = 0; dns->time.tv_nsec = 0;
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for (int i = 0; i < num_tests; i++) {
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struct hosts_list *curr = hosts;
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while (curr) {
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struct timespec run;
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run.tv_sec = -1; run.tv_nsec = 0;
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unsigned char buf[65536];
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for (int j = 0; j < 3 && run.tv_sec == -1; j++) {
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run = resolve(buf, curr->server, dns->server, T_A);
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}
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if (run.tv_sec == -1) //if test has failed 3 times, set time taken to 3s as penalty
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run.tv_sec = 3;
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dns->time.tv_sec += run.tv_sec;
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dns->time.tv_nsec += run.tv_nsec;
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if (dns->time.tv_nsec >= 1000000000) { //nanoseconds have overflowed into seconds
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dns->time.tv_sec += 1;
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dns->time.tv_nsec -= 1000000000;
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}
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tests_done++;
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curr = curr->next;
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}
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}
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avg_nsec = 1000000000*(dns->time.tv_sec%(num_hosts*num_tests))+dns->time.tv_nsec;
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dns->time.tv_sec = dns->time.tv_sec/(num_hosts*num_tests);
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dns->time.tv_nsec = avg_nsec/(num_hosts*num_tests);
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return NULL;
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}
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// Prints the progress every 0.1s for an indication of speed
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// tests_done is being written to in parallel, so may be overwritten but serves as a decent estimate of the progress
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void *print_progress(void *in)
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{
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struct timespec s;
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s.tv_sec = 0; s.tv_nsec = 100000000;
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while (1) {
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printf("\r%.2f%% done", ((float)tests_done)/(num_servers*num_hosts*num_tests) * 100);
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fflush(stdout);
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nanosleep(&s, NULL);
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}
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return NULL;
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}
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