/*
* anping 1.3
*
* ...is a simple ping programm, that
* sends icmp packets to a host to see
* whether it is up or not
*
* anping works with raw sockets, so you
* need to be root
*
* compiling: gcc anping.c -o anping
* usage: [root@localhost home]# ./anping
*
* coded by anfeu (gsicht) 06.11.2004
* anfeu@lycos.de
*
*/


#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <sys/select.h>
#include <sys/time.h>
#include <signal.h>

#define ANSWER_TIMEOUT 3
#define WHITE  ""
#define RED  ""
#define GREEN ""

void printerr(char *message)
{
printf("%sERROR: %s%s\n",RED,message,WHITE);
}

void usage(char *prog)
{
printf("\n%sUSAGE:%s\n",GREEN,WHITE);
printf("%s -s [source ip] -d [target host] -t <timeout> -c <packetnum>\n",prog);
printf(" -d [host]\tdest host\n");
printf(" -p [port]\tport to connect\n");
printf(" -t [seconds]\ttimeout for answer\n");
printf(" -c [packet number]\thow much packets?\n");
printf("example: %s -s 80.80.80.80 -d 80.61.54.22 -t 1 -c 5\n\n",prog);
exit(0);
}

void sigfunc(int sig)
{
char c;

if(sig != SIGINT)
return;
else
{
 printf("\n--interrupt--\n");
 sleep(1);
}
exit(0);
}


// i found this function somewhere in the internet
unsigned short in_cksum(unsigned short *ptr, int nbytes)
{
register long sum;
u_short oddbyte;
register u_short answer;

sum = 0;
while(nbytes > 1)
{
 sum += *ptr++;
 nbytes -= 2;
}

if(nbytes == 1)
{
 oddbyte = 0;
 *((u_char *) &oddbyte) = *(u_char *)ptr;
 sum += oddbyte;
}

sum  = (sum >> 16) + (sum & 0xffff);
sum += (sum >> 16);
answer = ~sum;

return(answer);
}
////

int main(int argc, char *argv[])
{

signal(SIGINT,sigfunc);

int sock,test=1,num;
int recvd = 0,sent = 0;
int i,n,c,timeout;

struct iphdr *ip;
struct icmphdr *icmp;

struct sockaddr_in addr;
struct in_addr addr2;

fd_set fdreadme;

char *packet;
char *data = "PING";
char buffer[512];

char *hostname;
char *sip;
struct hostent *host;

for(i=0;i<8;i++)
{
 if(argv[i] == NULL)
 usage(argv[0]);
//  if((strcmp(argv[i],"-h") != NULL) || (strcmp(argv[i],"--help") != NULL))
//  usage(argv[0]);
}



while((c = getopt(argc, argv, "s:d:t:c:"))!= EOF)
{
 switch (c)
 {
  case 's':
  sip = optarg;
  if(sip == NULL)
  {
   printerr("i don't know your ip address");
   usage(argv[0]);
  }  
  break;

  case 'd':
  hostname = optarg;
  if(hostname == NULL)
  {
   printerr("do this: -d dest host");
   usage(argv[0]);
  }
  break;

  case 't':
  if(optarg == NULL)
  timeout = ANSWER_TIMEOUT;
  timeout = atoi(optarg);
  break;

  case 'c':
  num = 3;
  if(optarg != NULL)
  num = atoi(optarg);
  break;

  default:
  usage(argv[0]);
  return 1;
 }
}

ip = (struct iphdr *) malloc(sizeof(struct iphdr));
icmp = (struct icmphdr *) malloc(sizeof(struct icmphdr));
packet = (char *) malloc(sizeof(struct iphdr) + sizeof(struct icmphdr) + sizeof(data) + 1);

memset(packet,0x00,sizeof(packet));

ip = (struct iphdr *)packet;
icmp = (struct icmphdr *) (packet + sizeof(struct iphdr));
strcpy(packet+sizeof(struct iphdr)+sizeof(struct icmphdr),data);

printf("\nsending ICMP packets to %s...\n\n",argv[2]);

ip->ihl = 5;
ip->version = 4;
ip->tos = 0;
ip->tot_len = sizeof(struct iphdr) + sizeof(struct icmphdr) + sizeof(data) + 1;
ip->id = htons(getuid());
ip->ttl = 255;
ip->protocol = IPPROTO_ICMP;
ip->saddr = inet_addr(sip);
ip->daddr = inet_addr(hostname);
ip->check = in_cksum((unsigned short *)ip, sizeof(struct iphdr));

sock = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
if(sock == -1)
{
 printerr("couldn't creat socket");
 return -1;
}

if(setsockopt(sock, IPPROTO_IP,IP_HDRINCL,&test,sizeof(test)) < 0)
{
 printerr("couldn't set IP_HDRINCL");
 return -1;
}

icmp->type = ICMP_ECHO;
icmp->code = 0;
icmp->un.echo.id = 0;
icmp->un.echo.sequence = 0;
icmp->checksum = in_cksum((unsigned short *)icmp,sizeof(struct icmphdr)+sizeof(data)+1);

addr.sin_family = AF_INET;
addr.sin_port = htons(31337);
addr.sin_addr.s_addr = inet_addr(hostname);

printf("starting...\n");

for(i=0;i<num;i++)
{
 fprintf(stdout,"PING...");
 if((sendto(sock,packet,ip->tot_len,0,(struct sockaddr *)&addr,sizeof(struct sockaddr))) < ip->tot_len)
 {
  printerr("couldn't send the packet");
 }
 else sent++;

 struct timeval tv;
 tv.tv_usec = 0;
 tv.tv_sec = timeout;

 FD_SET(sock, &fdreadme);
 FD_SET(0, &fdreadme);

 if(select(sock+1, &fdreadme, NULL, NULL, &tv) < 0 )
 {
  printerr("select() error");
  return -1;
 }

 if(FD_ISSET(sock, &fdreadme))
 {
  if(n = recv(sock, buffer, sizeof(buffer), 0) > 0)
  {
   addr2.s_addr = ip->daddr;
   printf("received ICMP packet from %s\n",inet_ntoa(addr2));
   recvd++;
  }
  if(n == -1)
  printerr("recv() failed");
 }
 else
 printerr("didn't receive answer. host seems down");
}
printf("\n-------- stats --------\n");
printf("%d packets transmitted, %d received\n...and the rest is silence\n",sent,recvd);
return 0;
}
/**** EOF ****/