adding first version of icmp.c

Author: alexander-naumov

sockets/RAW/icmp.c

@@ -0,0 +1,126 @@
+#include <error.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/utsname.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netdb.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <resolv.h>
+#include <netinet/ip_icmp.h>
+
+#define PACKETSIZE  64
+
+int pid=-1;
+struct protoent *proto=NULL;
+
+struct packet
+{
+    struct icmphdr hdr;
+    char msg[PACKETSIZE-sizeof(struct icmphdr)];
+};
+
+
+void usage()
+{
+    printf("USAGE:\t  ccns <IP_address>\n");
+    exit(1);
+}
+
+
+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;
+}
+
+int ping(char *host)
+{
+    struct hostent *hname;
+    struct sockaddr_in addr;
+
+    proto = getprotobyname("ICMP");
+    hname = gethostbyname(host);
+
+    bzero(&addr, sizeof(addr));
+
+    addr.sin_family = hname->h_addrtype;
+    addr.sin_port = 0;
+    addr.sin_addr.s_addr = *(long*)hname->h_addr;
+
+    const int val=255;
+    int i, sd, cnt=0;
+    struct packet pckt;
+    struct sockaddr_in r_addr;
+
+    sd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
+    if (sd < 0) {
+        perror("socket");
+        exit(1);
+    }
+
+    if (setsockopt(sd, SOL_IP, IP_TTL, &val, sizeof(val)) != 0)
+        perror("Set TTL option");
+
+    if (fcntl(sd, F_SETFL, O_NONBLOCK) != 0 )
+        perror("Request nonblocking I/O");
+
+    int count, icmp = 0;
+    for(count = 0; count < 4; count++) {
+        int len = sizeof(r_addr);
+
+        bzero(&pckt, sizeof(pckt));
+        pckt.hdr.type = ICMP_ECHO;
+        pckt.hdr.un.echo.id = pid;
+
+        for(i = 0; i < sizeof(pckt.msg)-1; i++)
+            pckt.msg[i] = i+'0';
+
+        pckt.msg[i] = 0;
+        pckt.hdr.un.echo.sequence = cnt++;
+        pckt.hdr.checksum = checksum(&pckt, sizeof(pckt));
+
+		printf("Msg #%d\n", cnt);
+        if (sendto(sd, &pckt, sizeof(pckt), 0, (struct sockaddr*)&addr, sizeof(addr)) <= 0 )
+            perror("sendto");
+
+        sleep(1);
+
+        if (recvfrom(sd, &pckt, sizeof(pckt), 0, (struct sockaddr*)&r_addr, &len) > 0 ) {
+            icmp++;
+			printf("***Got message!***\n");
+            if (icmp > 1)
+                return icmp;
+        }
+
+	}
+    return icmp;
+}
+
+int main(int argc, char *argv[])
+{
+    if(argv[1] == NULL)
+        usage();
+
+    if (ping(argv[1]) > 0)
+		printf("PING\t\tOK\n");
+    else
+		printf("PING\t\tNO_ANSWER\n");
+    
+	return 0;
+}
+