From b79b3a7406bc87fc57f4280449d809afad18ae04 Mon Sep 17 00:00:00 2001
From: Joel Grunbaum <joelgrun@gmail.com>
Date: Mon, 23 May 2022 12:51:16 +0000
Subject: [PATCH] Fix alignment with clang-format
---
dns.c | 498 ++++++++++++++++++++++++++++--------------------------
1 files changed, 259 insertions(+), 239 deletions(-)
diff --git a/dns.c b/dns.c
index 3784d2f..46c815c 100644
--- a/dns.c
+++ b/dns.c
@@ -1,14 +1,14 @@
+#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
-#include <arpa/inet.h>
//#include <netint/in.h>
//#include <netdb.h>
//#include <sys/time.h>
+#include "dns.h"
#include <time.h>
#include <unistd.h>
-#include "dns.h"
void change_to_DNS_name_format(unsigned char* dns, unsigned char* host);
char* read_name(unsigned char* reader, unsigned char* buffer, int* count);
@@ -17,287 +17,307 @@
// 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
+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;
+struct QUESTION {
+ unsigned short qtype;
+ unsigned short qclass;
};
/* Query structure */
-struct QUERY
-{
- unsigned char* name;
- struct QUESTION* ques;
+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;
+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;
+struct RES_RECORD {
+ char* name;
+ struct R_DATA resource;
+ char* rdata;
};
-struct timespec 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;
+ 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);
+ 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 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
+ // 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);
- sendto(s,(char*)buf, sizeof(struct DNS_HEADER)+strlen((const char*)qname)+1+sizeof(struct QUESTION), 0, (struct sockaddr*)&dest, sizeof(dest));
+ // 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));
- //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);
+ 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);
+ }
- 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;
+ // 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;
+ 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);
+ // 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;
- }
- }
+ 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 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);
+ // 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;
- }
- }
+ 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 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);
- }
+ // 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);
- }
+ 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,".");
+ 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';
+ 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';
+ 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;
- }
+ 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;
+ // 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;
}
--
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