From be527d670c50d6bbac90aec41cd87366e16515e4 Mon Sep 17 00:00:00 2001
From: Joel Grunbaum <joelgrun@gmail.com>
Date: Wed, 01 Jun 2022 10:00:01 +0000
Subject: [PATCH] Added input argument for reliability testing
---
main.c | 81 +++++++++++++++++++++++++++++-----------
1 files changed, 59 insertions(+), 22 deletions(-)
diff --git a/main.c b/main.c
index 340187f..9ac6e1f 100644
--- a/main.c
+++ b/main.c
@@ -16,7 +16,7 @@
#define NUM_TESTS 10
-int test_dns(void);
+int test_dns(int num_reach_tests);
void* test_server(void* in);
void* print_progress(void* in);
@@ -24,14 +24,15 @@
// Variables are only modified before threads are created and as such are
// thread-safe tests_done is modified to provide a rough count of number of
// tests being completed for progress measurement
-int tests_done = 0, num_tests = NUM_TESTS, num_servers = NUM_DNS, num_hosts = 0;
+int tests_done = 0, num_tests = NUM_TESTS, num_servers = 0, num_hosts = 0;
struct hosts_list* hosts = NULL;
struct dns_list* servers = NULL;
int main(int argc, char** argv)
{
int option, added_hosts = 0;
- while ((option = getopt(argc, argv, "s:a:t:n:h")) != -1) {
+ int num_reach_tests = 10;
+ while ((option = getopt(argc, argv, "s:a:t:n:r:h")) != -1) {
switch (option) {
case 's': // server to use
add_dns_server(&servers, optarg);
@@ -47,6 +48,9 @@
case 'n': // number of tests to perform
num_tests = atoi(optarg);
break;
+ case 'r': // number of tests for reachability
+ num_reach_tests = atoi(optarg);
+ break;
case '?':
case 'h':
default:
@@ -57,11 +61,12 @@
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 "
+ "all "
"available\n");
printf(
"\t-n <number>\tspecify the number of tests to perform on each "
"hostname\n\t\t\tdefaults to 10\n");
+ printf("\t-r <number>\tspecify the number of tests to run for reachability, defaulting to 10. Reachability testing only works when run as root\n");
printf("\t-h\t\tShow this help\n");
free_dns_list(&servers);
free_hosts_list(&hosts);
@@ -76,8 +81,9 @@
}
for (int i = 0; i < NUM_DNS; i++) {
add_dns_server(&servers, (char*)DNS_SERVERS[i]);
+ num_servers++;
}
- test_dns();
+ test_dns(num_reach_tests);
sort_servers(&servers);
print_servers(servers);
free_dns_list(&servers);
@@ -88,17 +94,48 @@
// Test each dns server individually
// Each test runs in its own thread and results are written to the respective
// dns_list
-int test_dns(void)
+int test_dns(int num_reach_tests)
{
struct dns_list* curr = servers;
int i = 0;
- pthread_t* threads = malloc(num_servers * sizeof(pthread_t));
+ int init_num_servers = num_servers;
+ pthread_t* threads;
pthread_t progress;
+
+ // Check each server for reachability, can't be done in parallel as incorrect packets are received
+ // reachable() requires raw packets, which needs root
+ if (getuid() == 0) {
+ while (curr) {
+ printf("\rTesting reachability: %d/%d", i, init_num_servers); fflush(stdout);
+ unsigned char* buf[65535];
+ int error_count = 0;
+ curr->errors = 0;
+ // retry 10 times for UDP unreliability
+ for (int i = 0; i < num_reach_tests; i++) {
+ error_count += (reachable((unsigned char*)buf, curr->server) != 0);
+ }
+ /* fprintf(stderr, "ip: %s, ec: %d\n", curr->server, error_count); */
+ // 30% error rate means unreachable
+ if (error_count >= (num_reach_tests * 3) / 10) {
+ curr->errors = -1 * error_count;
+ num_servers--;
+ }
+ curr = curr->next;
+ i++;
+ }
+ printf("\rTesting reachability: %d/%d\n", i, init_num_servers);
+ }
+
+ threads = malloc(num_servers * sizeof(pthread_t));
+ curr = servers;
+ i = 0;
pthread_create(&progress, NULL, print_progress, NULL);
while (curr) {
- pthread_create(&threads[i], NULL, test_server, (void*)curr);
+ if (curr->errors == 0) {
+ pthread_create(&threads[i], NULL, test_server, (void*)curr);
+ i++;
+ }
curr = curr->next;
- i++;
}
for (int i = 0; i < num_servers; i++) {
pthread_join(threads[i], NULL);
@@ -116,7 +153,6 @@
struct dns_list* dns = (struct dns_list*)in;
dns->time.tv_sec = 0;
dns->time.tv_nsec = 0;
- dns->errors = 0;
for (int i = 0; i < num_tests; i++) {
struct hosts_list* curr = hosts;
while (curr) {
@@ -127,18 +163,19 @@
for (int j = 0; j < 3 && run.tv_sec == -1; j++) {
run = resolve(buf, curr->server, dns->server, T_A);
}
- if (run.tv_sec == -1) { // if test has failed 3 times, set time taken
- // to 3s as penalty
- dns->errors++;
- } else {
- dns->time.tv_sec += run.tv_sec;
- dns->time.tv_nsec += run.tv_nsec;
- if (dns->time.tv_nsec >=
- 1000000000) { // nanoseconds have overflowed into seconds
- dns->time.tv_sec += 1;
- dns->time.tv_nsec -= 1000000000;
- }
- }
+ if (run.tv_sec ==
+ -1) { // if test has failed 3 times, set time taken
+ // to 3s as penalty
+ dns->errors++;
+ } else {
+ dns->time.tv_sec += run.tv_sec;
+ dns->time.tv_nsec += run.tv_nsec;
+ if (dns->time.tv_nsec >=
+ 1000000000) { // nanoseconds have overflowed into seconds
+ dns->time.tv_sec += 1;
+ dns->time.tv_nsec -= 1000000000;
+ }
+ }
tests_done++;
curr = curr->next;
}
--
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