From d3f3ee16d8adaef681afed67f236e3bb14e7cdc0 Mon Sep 17 00:00:00 2001
From: Joel Grunbaum <joelgrun@gmail.com>
Date: Wed, 21 Oct 2020 13:05:26 +0000
Subject: [PATCH] change artifact name and added penalty for failed connections
---
dns.c | 30 ++++++++++++++++++++++++++----
1 files changed, 26 insertions(+), 4 deletions(-)
diff --git a/dns.c b/dns.c
index 7499788..ad58873 100644
--- a/dns.c
+++ b/dns.c
@@ -6,6 +6,7 @@
//#include <netint/in.h>
//#include <netdb.h>
//#include <sys/time.h>
+#include <time.h>
#include <unistd.h>
#include "dns.h"
@@ -68,15 +69,20 @@
char* rdata;
};
-void resolve(unsigned char* buf, char* hostname, char* dns_ip, int query_type)
+// Test server dns_ip as IPv4 string for hostname
+// Writes received packet to buf, which is supplied and returns time for request
+struct timespec resolve(unsigned char* buf, char* hostname, char* dns_ip, int query_type)
{
int s, i;
struct sockaddr_in dest;
unsigned char *qname;
struct DNS_HEADER* dns = (struct DNS_HEADER*)buf;
struct QUESTION* qinfo;
+ struct timespec start, end, total, timeout;
+ timeout.tv_nsec=0; timeout.tv_sec=1;
s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+ setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(struct timespec)); //use a 1 second timeout for receiving, should be more than enough and anything more is really bad
dest.sin_family = AF_INET;
dest.sin_port = htons(53);
dest.sin_addr.s_addr = inet_addr(dns_ip);
@@ -107,15 +113,29 @@
//send request
// return less than 0 is a fail
+ clock_gettime(CLOCK_MONOTONIC, &start);
sendto(s,(char*)buf, sizeof(struct DNS_HEADER)+strlen((const char*)qname)+1+sizeof(struct QUESTION), 0, (struct sockaddr*)&dest, sizeof(dest));
//receive response
//negative return is a fail
i = sizeof(dest);
- recvfrom(s, (char*)buf, 65536, 0, (struct sockaddr*)&dest, (socklen_t*)&i);
- return;
+ i = recvfrom(s, (char*)buf, 65536, 0, (struct sockaddr*)&dest, (socklen_t*)&i);
+ clock_gettime(CLOCK_MONOTONIC, &end);
+
+ // Make sure packet was returned
+ if (i == -1)
+ total.tv_nsec = -1;
+ else
+ total.tv_sec = end.tv_sec - start.tv_sec;
+ if ((end.tv_nsec - start.tv_nsec) < 0)
+ total.tv_nsec = start.tv_nsec - end.tv_nsec;
+ else
+ total.tv_nsec = end.tv_nsec - start.tv_nsec;
+ close(s);
+ return total;
}
+// Print dns packet content, not terribly reliable but works for testing resolve with A requests
void print_packet(unsigned char* buf)
{
struct RES_RECORD answers[20], auth[20], addit[20];
@@ -226,7 +246,8 @@
}
}
-
+// convert from dot format to dns format
+// eg google.com to 6google3com
void change_to_DNS_name_format(unsigned char* dns, unsigned char* host)
{
int lock = 0;
@@ -246,6 +267,7 @@
*dns++ = '\0';
}
+// Convert from dns to dot format
char* read_name(unsigned char* reader, unsigned char* buffer, int* count)
{
char* name;
--
Gitblit v1.10.0