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- // C program to Implement Ping
- // compile as -o ping
- // run as sudo ./ping <hostname>
- #include <stdio.h>
- #include <sys/types.h>
- #include <sys/socket.h>
- #include <netinet/in.h>
- #include <arpa/inet.h>
- #include <netdb.h>
- #include <unistd.h>
- #include <string.h>
- #include <stdlib.h>
- #include <netinet/ip_icmp.h>
- #include <time.h>
- #include <fcntl.h>
- #include <signal.h>
- #include <time.h>
- // Define the Packet Constants
- // ping packet size
- #define PING_PKT_S 64
- // Automatic port number
- #define PORT_NO 0
- // Automatic port number
- #define PING_SLEEP_RATE 1000000 x
- // Gives the timeout delay for receiving packets
- // in seconds
- #define RECV_TIMEOUT 1
- // Define the Ping Loop
- int pingloop=1;
- // ping packet structure
- struct ping_pkt
- {
- struct icmphdr hdr;
- char msg[PING_PKT_S-sizeof(struct icmphdr)];
- };
- // Calculating the Check Sum
- unsigned short checksum(void *b, int len)
- { unsigned short *buf = b;
- unsigned int sum=0;
- unsigned short result;
- for ( sum = 0; len > 1; len -= 2 )
- sum += *buf++;
- if ( len == 1 )
- sum += *(unsigned char*)buf;
- sum = (sum >> 16) + (sum & 0xFFFF);
- sum += (sum >> 16);
- result = ~sum;
- return result;
- }
- // Interrupt handler
- void intHandler(int dummy)
- {
- pingloop=0;
- }
- // Performs a DNS lookup
- char *dns_lookup(char *addr_host, struct sockaddr_in *addr_con)
- {
- printf("\nResolving DNS..\n");
- struct hostent *host_entity;
- char *ip=(char*)malloc(NI_MAXHOST*sizeof(char));
- int i;
- if ((host_entity = gethostbyname(addr_host)) == NULL)
- {
- // No ip found for hostname
- return NULL;
- }
- //filling up address structure
- strcpy(ip, inet_ntoa(*(struct in_addr *)
- host_entity->h_addr));
- (*addr_con).sin_family = host_entity->h_addrtype;
- (*addr_con).sin_port = htons (PORT_NO);
- (*addr_con).sin_addr.s_addr = *(long*)host_entity->h_addr;
- return ip;
- }
- // Resolves the reverse lookup of the hostname
- char* reverse_dns_lookup(char *ip_addr)
- {
- struct sockaddr_in temp_addr;
- socklen_t len;
- char buf[NI_MAXHOST], *ret_buf;
- temp_addr.sin_family = AF_INET;
- temp_addr.sin_addr.s_addr = inet_addr(ip_addr);
- len = sizeof(struct sockaddr_in);
- if (getnameinfo((struct sockaddr *) &temp_addr, len, buf,
- sizeof(buf), NULL, 0, NI_NAMEREQD))
- {
- printf("Could not resolve reverse lookup of hostname\n");
- return NULL;
- }
- ret_buf = (char*)malloc((strlen(buf) +1)*sizeof(char) );
- strcpy(ret_buf, buf);
- return ret_buf;
- }
- // make a ping request
- void send_ping(int ping_sockfd, struct sockaddr_in *ping_addr,
- char *ping_dom, char *ping_ip, char *rev_host)
- {
- int ttl_val=64, msg_count=0, i, addr_len, flag=1,
- msg_received_count=0;
- struct ping_pkt pckt;
- struct sockaddr_in r_addr;
- struct timespec time_start, time_end, tfs, tfe;
- long double rtt_msec=0, total_msec=0;
- struct timeval tv_out;
- tv_out.tv_sec = RECV_TIMEOUT;
- tv_out.tv_usec = 0;
- clock_gettime(CLOCK_MONOTONIC, &tfs);
- // set socket options at ip to TTL and value to 64,
- // change to what you want by setting ttl_val
- if (setsockopt(ping_sockfd, SOL_IP, IP_TTL,
- &ttl_val, sizeof(ttl_val)) != 0)
- {
- printf("\nSetting socket options
- to TTL failed!\n");
- return;
- }
- else
- {
- printf("\nSocket set to TTL..\n");
- }
- // setting timeout of recv setting
- setsockopt(ping_sockfd, SOL_SOCKET, SO_RCVTIMEO,
- (const char*)&tv_out, sizeof tv_out);
- // send icmp packet in an infinite loop
- while(pingloop)
- {
- // flag is whether packet was sent or not
- flag=1;
- //filling packet
- bzero(&pckt, sizeof(pckt));
- pckt.hdr.type = ICMP_ECHO;
- pckt.hdr.un.echo.id = getpid();
- for ( i = 0; i < sizeof(pckt.msg)-1; i++ )
- pckt.msg[i] = i+'0';
- pckt.msg[i] = 0;
- pckt.hdr.un.echo.sequence = msg_count++;
- pckt.hdr.checksum = checksum(&pckt, sizeof(pckt));
- usleep(PING_SLEEP_RATE);
- //send packet
- clock_gettime(CLOCK_MONOTONIC, &time_start);
- if ( sendto(ping_sockfd, &pckt, sizeof(pckt), 0,
- (struct sockaddr*) ping_addr,
- sizeof(*ping_addr)) <= 0)
- {
- printf("\nPacket Sending Failed!\n");
- flag=0;
- }
- //receive packet
- addr_len=sizeof(r_addr);
- if ( recvfrom(ping_sockfd, &pckt, sizeof(pckt), 0,
- (struct sockaddr*)&r_addr, &addr_len) <= 0
- && msg_count>1)
- {
- printf("\nPacket receive failed!\n");
- }
- else
- {
- clock_gettime(CLOCK_MONOTONIC, &time_end);
- double timeElapsed = ((double)(time_end.tv_nsec -
- time_start.tv_nsec))/1000000.0
- rtt_msec = (time_end.tv_sec-
- time_start.tv_sec) * 1000.0
- + timeElapsed;
- // if packet was not sent, don't receive
- if(flag)
- {
- if(!(pckt.hdr.type ==69 && pckt.hdr.code==0))
- {
- printf("Error..Packet received with ICMP
- type %d code %d\n",
- pckt.hdr.type, pckt.hdr.code);
- }
- else
- {
- printf("%d bytes from %s (h: %s)
- (%s) msg_seq=%d ttl=%d
- rtt = %Lf ms.\n",
- PING_PKT_S, ping_dom, rev_host,
- ping_ip, msg_count,
- ttl_val, rtt_msec);
- msg_received_count++;
- }
- }
- }
- }
- clock_gettime(CLOCK_MONOTONIC, &tfe);
- double timeElapsed = ((double)(tfe.tv_nsec -
- tfs.tv_nsec))/1000000.0;
- total_msec = (tfe.tv_sec-tfs.tv_sec)*1000.0+
- timeElapsed
- printf("\n===%s ping statistics===\n", ping_ip);
- printf("\n%d packets sent, %d packets received, %f percent
- packet loss. Total time: %Lf ms.\n\n",
- msg_count, msg_received_count,
- ((msg_count - msg_received_count)/msg_count) * 100.0,
- total_msec);
- }
- // Driver Code
- int main(int argc, char *argv[])
- {
- int sockfd;
- char *ip_addr, *reverse_hostname;
- struct sockaddr_in addr_con;
- int addrlen = sizeof(addr_con);
- char net_buf[NI_MAXHOST];
- if(argc!=2)
- {
- printf("\nFormat %s <address>\n", argv[0]);
- return 0;
- }
- ip_addr = dns_lookup(argv[1], &addr_con);
- if(ip_addr==NULL)
- {
- printf("\nDNS lookup failed! Could
- not resolve hostname!\n");
- return 0;
- }
- reverse_hostname = reverse_dns_lookup(ip_addr);
- printf("\nTrying to connect to '%s' IP: %s\n",
- argv[1], ip_addr);
- printf("\nReverse Lookup domain: %s",
- reverse_hostname);
- //socket()
- sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
- if(sockfd<0)
- {
- printf("\nSocket file descriptor not received!!\n");
- return 0;
- }
- else
- printf("\nSocket file descriptor %d received\n", sockfd);
- signal(SIGINT, intHandler);//catching interrupt
- //send pings continuously
- send_ping(sockfd, &addr_con, reverse_hostname,
- ip_addr, argv[1]);
- return 0;
- }
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