From 6dab04021cc1f97e5d95ca7da56e95a1fed8046a Mon Sep 17 00:00:00 2001
From: Joel Grunbaum <joelgrun@gmail.com>
Date: Tue, 31 May 2022 13:47:51 +0000
Subject: [PATCH] Further update to listen for any traffic. Need to refine to returning DNS or ICMP about DNS
---
test.c | 7 +
/dev/null | 0
.gitignore | 5 +
dns.c | 201 ++++++++++++++++++++++++++------------------------
4 files changed, 114 insertions(+), 99 deletions(-)
diff --git "a/\043dns.c\043" "b/\043dns.c\043"
deleted file mode 100644
index fc24762..0000000
--- "a/\043dns.c\043"
+++ /dev/null
@@ -1,415 +0,0 @@
-#include <arpa/inet.h>
-#include <asm-generic/socket.h>
-#include <netinet/in.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/socket.h>
-//#include <netint/in.h>
-//#include <netdb.h>
-//#include <sys/time.h>
-#include "dns.h"
-#include <time.h>
-#include <unistd.h>
-#include <errno.h>
-
-void change_to_DNS_name_format(unsigned char* dns, unsigned char* host);
-char* read_name(unsigned char* reader, unsigned char* buffer, int* count);
-void fill_ICMP_data(unsigned char* icmp_data, int datasize);
-unsigned short icmp_checksum(unsigned short* buf, int size);
-
-// DNS code copied from
-// https://gist.github.com/fffaraz/9d9170b57791c28ccda9255b48315168
-
-/* DNS header struct */
-struct DNS_HEADER {
- unsigned short id; // ID number
- unsigned char rd : 1; // recursion
- unsigned char tc : 1; // truncated message
- unsigned char aa : 1; // authoritive answer
- unsigned char opcode : 4; // message purpose
- unsigned char qr : 1; // query response
- unsigned char rcode : 4; // response code
- unsigned char cd : 1; // checking disabled
- unsigned char ad : 1; // authenticated data
- unsigned char z : 1; // reserved for future use
- unsigned char ra : 1; // recursion available
- unsigned short q_count; // number of question entrise
- unsigned short ans_count; // number of answer entries
- unsigned short auth_count; // number of authority entries
- unsigned short add_count; // number of resource entries
-};
-
-/* structured for query structure */
-struct QUESTION {
- unsigned short qtype;
- unsigned short qclass;
-};
-
-/* Query structure */
-struct QUERY {
- unsigned char* name;
- struct QUESTION* ques;
-};
-
-/* Constant sized fields of record structure */
-#pragma pack(push, 1)
-struct R_DATA {
- unsigned short type;
- unsigned short _class;
- unsigned int ttl;
- unsigned short data_len;
-};
-#pragma pack(pop)
-
-/* Pointers to record components */
-struct RES_RECORD {
- char* name;
- struct R_DATA resource;
- char* rdata;
-};
-
-#define ICMP_ECHO 8
-#define ICMP_ECHOREPLY 0
-
-struct ICMP_HEADER {
- unsigned char type;
- unsigned char code;
- short checksum;
- short id;
- short seq;
- long timestamp;
-};
-
-// Test if an IP address is hosting a DNS server
-int reachable(unsigned char* buf, char* dns_ip)
-{
- int s, r;
- int datasize = 64;
- struct sockaddr_in dest;
- struct timespec timeout;
- timeout.tv_sec = 1;
- timeout.tv_nsec = 0;
-
- dest.sin_family = AF_INET;
- dest.sin_port = htons(53);
- dest.sin_addr.s_addr = inet_addr(dns_ip);
-
- if (0) {
- s = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
- if (s < 0) {
- printf("%d, %s\n", s, strerror(errno));
- return -1;
- }
- setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(struct timespec));
-
- fill_ICMP_data(buf, datasize);
- ((struct ICMP_HEADER*)buf)->checksum = icmp_checksum((unsigned short*)buf, datasize);
-
- r = sendto(s, buf, datasize, 0, (struct sockaddr*)&dest, sizeof(dest));
- printf("%d\n", r);
- }
-
- s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
- if (s < 0) {
- printf("%d, %s\n", s, strerror(errno));
- return -1;
- }
- setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(struct timespec));
-
- r = connect(s, (struct sockaddr*)&dest, sizeof(dest));
- printf("%d", r);
-
-
-
- return 1;
-}
-
-// 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);
-
- // dns packet header
- dns->id = (unsigned short)htons(getpid());
- dns->qr = 0; // make query
- dns->opcode = 0; // standard query
- dns->aa = 0; // not authoritive
- dns->tc = 0; // not trucated
- dns->rd = 1; // want recursion
- dns->ra = 0; // recursion not available
- dns->z = 0;
- dns->ad = 0;
- dns->cd = 0;
- dns->rcode = 0;
- dns->q_count = htons(1); // one question
- dns->ans_count = 0;
- dns->auth_count = 0;
- dns->add_count = 0;
-
- // dns packet query
- qname = (unsigned char*)&buf[sizeof(struct DNS_HEADER)];
- change_to_DNS_name_format(qname, (unsigned char*)hostname);
- qinfo = (struct QUESTION*)&buf[sizeof(struct DNS_HEADER) +
- strlen((const char*)qname) + 1];
- qinfo->qtype = htons(
- query_type); // type of query from argument (A,AAAA,MX,CNAME,NS,...)
- qinfo->qclass = htons(1); // internet class
-
- // send request
- // return less than 0 is a fail
- clock_gettime(CLOCK_MONOTONIC, &start);
- i = sendto(s, (char*)buf,
- sizeof(struct DNS_HEADER) + strlen((const char*)qname) + 1 +
- sizeof(struct QUESTION),
- 0, (struct sockaddr*)&dest, sizeof(dest));
-
- if (i >= 0) {
- // receive response
- // negative return is a fail
- i = sizeof(dest);
- 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];
- struct DNS_HEADER* dns;
- struct sockaddr_in a;
- unsigned char *qname = buf + sizeof(struct DNS_HEADER), *reader;
- int stop, i, j;
- dns = (struct DNS_HEADER*)buf;
- reader = &buf[sizeof(struct DNS_HEADER) + strlen((const char*)qname) + 1 +
- sizeof(struct QUESTION)];
- printf("Response contains %d Qs, %d ans, %d auth serv, %d add reconds\n",
- ntohs(dns->q_count), ntohs(dns->ans_count), ntohs(dns->auth_count),
- ntohs(dns->add_count));
- stop = 0;
-
- // read answers
- for (i = 0; i < ntohs(dns->ans_count); i++) {
- answers[i].name = read_name(reader, buf, &stop);
- reader = reader + stop;
- memcpy(&(answers[i].resource), reader, sizeof(struct R_DATA));
- reader = reader + sizeof(struct R_DATA);
-
- if (ntohs(answers[i].resource.type) == T_A) { // IPv4 address
- answers[i].rdata =
- (char*)malloc(ntohs(answers[i].resource.data_len));
- for (j = 0; j < ntohs(answers[i].resource.data_len); j++) {
- answers[i].rdata[j] = reader[j];
- }
- answers[i].rdata[ntohs(answers[i].resource.data_len)] = '\0';
- reader = reader + ntohs(answers[i].resource.data_len);
- } else {
- answers[i].rdata = read_name(reader, buf, &stop);
- reader = reader + stop;
- }
- }
-
- // read authorities
- for (i = 0; i < ntohs(dns->auth_count); i++) {
- auth[i].name = read_name(reader, buf, &stop);
- reader += stop;
- memcpy(&(auth[i].resource), reader, sizeof(struct R_DATA));
- reader += sizeof(struct R_DATA);
- auth[i].rdata = read_name(reader, buf, &stop);
- reader += stop;
- }
-
- // read additional
- for (i = 0; i < ntohs(dns->add_count); i++) {
- addit[i].name = read_name(reader, buf, &stop);
- reader += stop;
- memcpy(&(addit[i].resource), reader, sizeof(struct R_DATA));
- reader += sizeof(struct R_DATA);
-
- if (ntohs(addit[i].resource.type) == 1) {
- addit[i].rdata = malloc(ntohs(addit[i].resource.data_len));
- for (j = 0; j < ntohs(addit[i].resource.data_len); j++)
- addit[i].rdata[j] = reader[j];
- addit[i].rdata[ntohs(addit[i].resource.data_len)] = '\0';
- reader += ntohs(addit[i].resource.data_len);
- } else {
- addit[i].rdata = read_name(reader, buf, &stop);
- reader += stop;
- }
- }
-
- // print answers
- printf("ans recs: %d\n", ntohs(dns->ans_count));
- for (i = 0; i < ntohs(dns->ans_count); i++) {
- printf("name: %s ", answers[i].name);
- if (ntohs(answers[i].resource.type) == T_A) { // IPv4
- long* p;
- p = (long*)answers[i].rdata;
- a.sin_addr.s_addr = (*p);
- printf("has IPv4 addresss: %s", inet_ntoa(a.sin_addr));
- } else if (ntohs(answers[i].resource.type) == T_CNAME) { // CNAME
- printf("has alias: %s", answers[i].rdata);
- }
- free(answers[i].name);
- free(answers[i].rdata);
- putc('\n', stdout);
- }
-
- // print authorities
- printf("Auth recs: %d\n", ntohs(dns->auth_count));
- for (i = 0; i < ntohs(dns->auth_count); i++) {
- printf("name: %s ", auth[i].name);
- if (ntohs(auth[i].resource.type) == 1) {
- long* p;
- p = (long*)auth[i].rdata;
- a.sin_addr.s_addr = *p;
- printf("has IPv4 address: %s", inet_ntoa(a.sin_addr));
- }
- free(answers[i].name);
- free(auth[i].rdata);
- putc('\n', stdout);
- }
-
- printf("Addit recs: %d\n", ntohs(dns->add_count));
- for (i = 0; i < ntohs(dns->add_count); i++) {
- printf("name; %s", addit[i].name);
- if (ntohs(auth[i].resource.type) == 1) {
- long* p;
- p = (long*)addit[i].rdata;
- a.sin_addr.s_addr = *p;
- printf("has IPv4 address: %s", inet_ntoa(a.sin_addr));
- } else {
- printf("has %s", addit[i].rdata);
- }
- free(answers[i].name);
- free(addit[i].rdata);
- putc('\n', stdout);
- }
-}
-
-// 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;
- char h[300];
- strcpy(h, (char*)host);
- strcat((char*)h, ".");
-
- for (int i = 0; i < strlen(h); i++) {
- if (h[i] == '.') {
- *dns++ = i - lock;
- for (; lock < i; lock++) {
- *dns++ = h[lock];
- }
- lock++;
- }
- }
- *dns++ = '\0';
-}
-
-// Convert from dns to dot format
-char* read_name(unsigned char* reader, unsigned char* buffer, int* count)
-{
- char* name;
- unsigned int p = 0, jumped = 0, offset;
- int i, j;
- *count = 1;
- name = (char*)malloc(256);
- name[0] = '\0';
-
- while (*reader != 0) {
- if (*reader >= 192) {
- offset = (*reader) * 256 + *(reader + 1) - 49152;
- reader = buffer + offset - 1;
- jumped = 1;
- } else {
- name[p++] = *reader;
- }
- reader = reader + 1;
- if (jumped == 0) {
- *count = *count + 1;
- }
- }
- name[p] = '\0';
- if (jumped == 1) {
- *count = *count + 1;
- }
-
- // convert from dns format to normal
- for (i = 0; i < strlen((const char*)name); i++) {
- p = name[i];
- for (j = 0; j < p; j++) {
- name[i] = name[i + 1];
- i++;
- }
- name[i] = '.';
- }
- name[i - 1] = '\0';
- return name;
-}
-
-// Populate the sending ICMP packet with data
-void fill_ICMP_data(unsigned char* icmp_data, int datasize)
-{
- struct ICMP_HEADER* h = (struct ICMP_HEADER*)icmp_data;
- unsigned char* d = icmp_data + sizeof(struct ICMP_HEADER);
-
- h->type = ICMP_ECHO;
- h->code = 0;
- h->id = getpid();
- h->checksum = 0;
- h->seq = 0;
-
- memset(d, 'A', datasize - sizeof(struct ICMP_HEADER));
-}
-
-// Calculate the ICMP checksum
-unsigned short icmp_checksum(unsigned short* buf, int size)
-{
- unsigned long checksum = 0;
- while (size > 1) {
- checksum += *buf++;
- size -= sizeof(unsigned short);
- }
- if (size) {
- checksum += *buf;
- }
- checksum = (checksum >> 16) + (checksum & 0xffff);
- checksum += checksum >> 16;
- return (unsigned short)~checksum;
-}
diff --git "a/.\043dns.c" "b/.\043dns.c"
deleted file mode 120000
index a1a7d72..0000000
--- "a/.\043dns.c"
+++ /dev/null
@@ -1 +0,0 @@
-joel@iThink.1594:1653970026
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index d297a5f..fdf8ca8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,7 @@
*.o
*.out
*~
-dnscomp
\ No newline at end of file
+dnscomp
+\#*
+*#
+test
\ No newline at end of file
diff --git a/dns.c b/dns.c
index 3708389..9095878 100644
--- a/dns.c
+++ b/dns.c
@@ -1,22 +1,23 @@
+#include "dns.h"
#include <arpa/inet.h>
#include <asm-generic/socket.h>
+#include <bits/time.h>
+#include <errno.h>
+#include <linux/if_ether.h>
#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <netinet/ip_icmp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
-//#include <netint/in.h>
-//#include <netdb.h>
-//#include <sys/time.h>
-#include "dns.h"
#include <time.h>
#include <unistd.h>
-#include <errno.h>
void change_to_DNS_name_format(unsigned char* dns, unsigned char* host);
char* read_name(unsigned char* reader, unsigned char* buffer, int* count);
-void fill_ICMP_data(unsigned char* icmp_data, int datasize);
-unsigned short icmp_checksum(unsigned short* buf, int size);
+int fill_DNS_data(unsigned char* buf, int datasize, char* hostname,
+ int query_type);
// DNS code copied from
// https://gist.github.com/fffaraz/9d9170b57791c28ccda9255b48315168
@@ -69,25 +70,20 @@
char* rdata;
};
-#define ICMP_ECHO 8
-#define ICMP_ECHOREPLY 0
-
-struct ICMP_HEADER {
- unsigned char type;
- unsigned char code;
- short checksum;
- short id;
- short seq;
- long timestamp;
-};
+#define IP_ICMP 1
+#define IP_TCP 6
+#define IP_UDP 17
// Test if an IP address is hosting a DNS server
int reachable(unsigned char* buf, char* dns_ip)
{
- int s, r;
- int datasize = 64;
+ int s, r, ret, name_len;
struct sockaddr_in dest;
- struct timespec timeout;
+ socklen_t dest_len = sizeof(dest);
+ struct timespec timeout, start, end;
+ struct icmphdr* icmp_head;
+ struct ip* ip_head;
+ unsigned char buf_send[65535];
timeout.tv_sec = 1;
timeout.tv_nsec = 0;
@@ -95,32 +91,63 @@
dest.sin_port = htons(53);
dest.sin_addr.s_addr = inet_addr(dns_ip);
- if (0) {
- s = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
- if (s < 0) {
- printf("%d, %s\n", s, strerror(errno));
- return -1;
+ s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+ /* r = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP); */
+ r = socket(AF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL));
+ if (r < 0) {
+ printf("%d, %s\n", r, strerror(errno));
+ return -1;
+ }
+ setsockopt(r, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(struct timespec));
+
+ name_len = fill_DNS_data((unsigned char*)&buf_send, 65535, "google.com", T_A);
+ ret = sendto(s, buf_send,
+ sizeof(struct DNS_HEADER) + name_len + 1 +
+ sizeof(struct QUESTION),
+ 0, (struct sockaddr*)&dest, sizeof(dest));
+
+ clock_gettime(CLOCK_MONOTONIC, &start);
+ do {
+ ret = recvfrom(r, buf, 65535, 0, (struct sockaddr*)&dest, &dest_len);
+ clock_gettime(CLOCK_MONOTONIC, &end);
+ if (!memcmp(&buf_send, buf, 100)) {
+ printf("*1\n");
+ break;
}
- setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(struct timespec));
+ } while (start.tv_sec + 2 > end.tv_sec);
- fill_ICMP_data(buf, datasize);
- ((struct ICMP_HEADER*)buf)->checksum = icmp_checksum((unsigned short*)buf, datasize);
+ close(s);
+ close(r);
- r = sendto(s, buf, datasize, 0, (struct sockaddr*)&dest, sizeof(dest));
- printf("%d\n", r);
- }
+ printf("diff: %d\n", memcmp(&buf_send, buf, 100));
- s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
- if (s < 0) {
- printf("%d, %s\n", s, strerror(errno));
- return -1;
- }
- setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(struct timespec));
+ ip_head = (struct ip*)buf;
+ icmp_head = (struct icmphdr*)buf + sizeof(struct ip);
- r = connect(s, (struct sockaddr*)&dest, sizeof(dest));
- printf("%d", r);
+ for (int i = 0; i < 93; i++) {
+ printf("%02X", buf[i]);
+ }
+ printf("\n");
- return 1;
+ printf("len: %d, ver: %d, tos: %d, tlen: %d, ident: %d, ff: %d, ttl: %d, "
+ "pro: %d, cs: %d, sip: %d, dip: %d\n",
+ ip_head->ip_hl, ip_head->ip_v, ip_head->ip_tos, ip_head->ip_len,
+ ip_head->ip_id, ip_head->ip_off, ip_head->ip_ttl, ip_head->ip_p,
+ ip_head->ip_sum, ip_head->ip_src.s_addr, ip_head->ip_dst.s_addr);
+
+ if (ip_head->ip_p != IP_UDP) {
+ if (ip_head->ip_p == IP_ICMP) {
+ return 1;
+ } else {
+ printf("%d\n", ip_head->ip_p);
+ for (int i = 0; i < sizeof(struct ip); i++) {
+ printf("%02X", buf[i]);
+ }
+ printf("\n");
+ return 2;
+ }
+ }
+ return 0;
}
// Test server dns_ip as IPv4 string for hostname
@@ -128,11 +155,9 @@
struct timespec resolve(unsigned char* buf, char* hostname, char* dns_ip,
int query_type)
{
- int s, i;
+ int s, i, name_len;
struct sockaddr_in dest;
- unsigned char* qname;
- struct DNS_HEADER* dns = (struct DNS_HEADER*)buf;
- struct QUESTION* qinfo;
+ socklen_t dest_len = sizeof(dest);
struct timespec start, end, total, timeout;
timeout.tv_nsec = 0;
timeout.tv_sec = 1;
@@ -147,37 +172,13 @@
dest.sin_port = htons(53);
dest.sin_addr.s_addr = inet_addr(dns_ip);
- // dns packet header
- dns->id = (unsigned short)htons(getpid());
- dns->qr = 0; // make query
- dns->opcode = 0; // standard query
- dns->aa = 0; // not authoritive
- dns->tc = 0; // not trucated
- dns->rd = 1; // want recursion
- dns->ra = 0; // recursion not available
- dns->z = 0;
- dns->ad = 0;
- dns->cd = 0;
- dns->rcode = 0;
- dns->q_count = htons(1); // one question
- dns->ans_count = 0;
- dns->auth_count = 0;
- dns->add_count = 0;
-
- // dns packet query
- qname = (unsigned char*)&buf[sizeof(struct DNS_HEADER)];
- change_to_DNS_name_format(qname, (unsigned char*)hostname);
- qinfo = (struct QUESTION*)&buf[sizeof(struct DNS_HEADER) +
- strlen((const char*)qname) + 1];
- qinfo->qtype = htons(
- query_type); // type of query from argument (A,AAAA,MX,CNAME,NS,...)
- qinfo->qclass = htons(1); // internet class
+ name_len = fill_DNS_data(buf, 65535, hostname, query_type);
// send request
// return less than 0 is a fail
clock_gettime(CLOCK_MONOTONIC, &start);
i = sendto(s, (char*)buf,
- sizeof(struct DNS_HEADER) + strlen((const char*)qname) + 1 +
+ sizeof(struct DNS_HEADER) + name_len + 1 +
sizeof(struct QUESTION),
0, (struct sockaddr*)&dest, sizeof(dest));
@@ -186,7 +187,7 @@
// negative return is a fail
i = sizeof(dest);
i = recvfrom(s, (char*)buf, 65536, 0, (struct sockaddr*)&dest,
- (socklen_t*)&i);
+ &dest_len);
clock_gettime(CLOCK_MONOTONIC, &end);
}
@@ -381,33 +382,39 @@
return name;
}
-// Populate the sending ICMP packet with data
-void fill_ICMP_data(unsigned char* icmp_data, int datasize)
+// Populate the sending DNS packet with data
+int fill_DNS_data(unsigned char* buf, int datasize, char* hostname,
+ int query_type)
{
- struct ICMP_HEADER* h = (struct ICMP_HEADER*)icmp_data;
- unsigned char* d = icmp_data + sizeof(struct ICMP_HEADER);
+ struct DNS_HEADER* dns = (struct DNS_HEADER*)buf;
+ struct QUESTION* qinfo;
+ unsigned char* qname;
- h->type = ICMP_ECHO;
- h->code = 0;
- h->id = getpid();
- h->checksum = 0;
- h->seq = 0;
+ // dns packet header
+ dns->id = (unsigned short)htons(getpid());
+ dns->qr = 0; // make query
+ dns->opcode = 0; // standard query
+ dns->aa = 0; // not authoritive
+ dns->tc = 0; // not trucated
+ dns->rd = 1; // want recursion
+ dns->ra = 0; // recursion not available
+ dns->z = 0;
+ dns->ad = 0;
+ dns->cd = 0;
+ dns->rcode = 0;
+ dns->q_count = htons(1); // one question
+ dns->ans_count = 0;
+ dns->auth_count = 0;
+ dns->add_count = 0;
- memset(d, 'A', datasize - sizeof(struct ICMP_HEADER));
-}
+ // dns packet query
+ qname = (unsigned char*)&buf[sizeof(struct DNS_HEADER)];
+ change_to_DNS_name_format(qname, (unsigned char*)hostname);
+ qinfo = (struct QUESTION*)&buf[sizeof(struct DNS_HEADER) +
+ strlen((const char*)qname) + 1];
+ qinfo->qtype = htons(
+ query_type); // type of query from argument (A,AAAA,MX,CNAME,NS,...)
+ qinfo->qclass = htons(1); // internet class
-// Calculate the ICMP checksum
-unsigned short icmp_checksum(unsigned short* buf, int size)
-{
- unsigned long checksum = 0;
- while (size > 1) {
- checksum += *buf++;
- size -= sizeof(unsigned short);
- }
- if (size) {
- checksum += *buf;
- }
- checksum = (checksum >> 16) + (checksum & 0xffff);
- checksum += checksum >> 16;
- return (unsigned short)~checksum;
+ return strlen((const char*)qname);
}
diff --git a/test b/test
deleted file mode 100755
index 9d0d5ab..0000000
--- a/test
+++ /dev/null
Binary files differ
diff --git a/test.c b/test.c
index 2bef6e4..7ddbf1c 100644
--- a/test.c
+++ b/test.c
@@ -2,6 +2,7 @@
#include <stdlib.h>
#include "dns.h"
#include <time.h>
+#include <netinet/ip.h>
int main(void)
{
@@ -12,7 +13,11 @@
struct timespec ret;
int r;
- r = reachable(buf, IP);
+ r = reachable(buf, "10.0.0.0");
+ printf("%d\n", r);
+ /* print_packet(buf + sizeof(struct ip)); */
+ r = reachable(buf, "127.0.0.2");
+ printf("%d\n", r);
/* ret = resolve(buf, hostname, IP, type); */
--
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