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 |  486 +++++++++++++++++++++++++++++-------------------------
 1 files changed, 261 insertions(+), 225 deletions(-)

diff --git a/dns.c b/dns.c
index 7499788..46c815c 100644
--- a/dns.c
+++ b/dns.c
@@ -1,13 +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 <unistd.h>
 #include "dns.h"
+#include <time.h>
+#include <unistd.h>
 
 void change_to_DNS_name_format(unsigned char* dns, unsigned char* host);
 char* read_name(unsigned char* reader, unsigned char* buffer, int* count);
@@ -16,272 +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;
 };
 
-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;
+	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);
-	 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
-	 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);
-	 recvfrom(s, (char*)buf, 65536, 0, (struct sockaddr*)&dest, (socklen_t*)&i);
-	 return;
+	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;
+	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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