1 files changed, 176 insertions, 0 deletions

diff --git a/other/itunnel/it.c b/other/itunnel/it.c
new file mode 100644
index 0000000..a1741c1
--- /dev/null
+++ b/other/itunnel/it.c
@@ -0,0 +1,176 @@
+/*
+ * itunnel - an ICMP tunnel by edi / teso
+ * usage: it [-i id] [-s packetsize] host
+ * establishes   a   bidirectional   ICMP 
+ * 'connection' with 'host'  by listening 
+ * to  ICMP  packets with  a  specific id
+ * (default: 7530). uses stdin and stdout
+ * and needs to run as root.
+ *
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/socket.h>
+#include <netinet/in_systm.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
+struct icmp
+{
+        u_int8_t        type;
+        u_int8_t        code;
+        u_int16_t       cksum;
+        u_int16_t       id;
+        u_int16_t       seq;
+};
+
+u_short in_cksum(u_short *, int);
+
+/* icmp_tunnel - does the ICMP tunneling :-)
+int sock - ICMP socket used to communicate
+struct sockaddr_in *target - other side
+int infd - input
+int outfd - output
+int packetsize - ...
+u_int16_t id - ...
+*/
+
+int icmp_tunnel(int sock, struct sockaddr_in *target, int infd, int outfd, int packetsize, u_int16_t id) {
+
+        char* packet;
+        struct icmp *icmp, *icmpr;
+        int len;
+        int result;
+        fd_set fs;
+
+        struct sockaddr_in from;
+        int fromlen;
+        int num;
+
+        len = sizeof (struct icmp);
+
+        packet = malloc (len+packetsize);
+        memset (packet, 0, len+packetsize);
+
+        icmp = (struct icmp*)(packet);
+        icmpr = (struct icmp*)(packet+sizeof(struct ip));
+
+        while (1) {
+                FD_ZERO (&fs);
+                FD_SET (infd, &fs);
+                FD_SET (sock, &fs);
+
+                select (infd>sock?infd+1:sock+1, &fs, NULL, NULL, NULL);
+
+                if (FD_ISSET (infd, &fs)) {
+                        result = read (infd, packet+len, packetsize);
+                        if (!result) {
+                                return 0;
+                        } else if (result==-1) {
+                                perror ("read");
+                                return -1;
+                        }
+                        icmp->type = 0;
+                        icmp->code = 0;
+                        icmp->id = id;
+                        icmp->seq = 0;
+                        icmp->cksum = 0;
+                        icmp->cksum = in_cksum((u_short*)packet, len+result);
+                        result = sendto (sock, (char*)packet, len+result, 0, (struct sockaddr*)target, sizeof (struct sockaddr_in));
+                        if (result==-1) {
+                                perror ("sendto");
+                                return -1;
+                        }
+                }
+                if (FD_ISSET (sock, &fs)) {
+                        fromlen = sizeof (struct sockaddr_in);
+                        num = recvfrom (sock, packet, len+packetsize, 0, (struct sockaddr*)&from, &fromlen);
+                        if (icmpr->id == id) {
+                                write (outfd, packet+sizeof(struct ip)+sizeof(struct icmp), num-sizeof(struct ip)-sizeof(struct icmp));
+                        }
+                }
+        }
+
+
+        return 0;
+}
+
+int main (int argc, char** argv) {
+        struct sockaddr_in target;
+        int s;
+
+        int packetsize = 100;
+        char* desthost = NULL;
+        u_int16_t id = 7530;
+
+        argv++;
+        argc--;
+
+        while (argc--) {
+                if (!strcmp(*argv, "-i")) {
+                        if (!argc--) {
+                                fprintf (stderr, "need argument\n");
+                                return -1;
+                        }
+                        argv++;
+                        id = atoi(*argv++);
+                } else if (!strcmp(*argv, "-s")) {
+                        if (!argc--) {
+                                fprintf (stderr, "need argument\n");
+                                return -1;
+                        }
+                        argv++;
+                        packetsize = atoi(*argv++);
+                } else desthost = *argv++;
+        }
+
+        if (!desthost) {
+                fprintf (stderr, "no destination\n");
+                return -1;
+        }
+
+        if ((target.sin_addr.s_addr = inet_addr (desthost)) == -1) {
+                struct hostent* he;
+                if (!(he = gethostbyname (desthost))) {
+                        herror ("gethostbyname");
+                        return -1;
+                }
+                memcpy (&target.sin_addr.s_addr, he->h_addr, he->h_length);
+        }
+        target.sin_family = AF_INET;
+
+        if ( (s = socket (AF_INET, SOCK_RAW, IPPROTO_ICMP)) == -1) {
+                perror ("socket");
+                return -1;
+        }
+
+        icmp_tunnel(s, &target, STDIN_FILENO, STDOUT_FILENO, packetsize, id);
+
+        close(s);
+
+        return 0;
+}
+
+unsigned short
+in_cksum (addr, len)
+     u_short *addr;
+     int len;
+{
+  register int nleft = len;
+  register u_short *w = addr;
+  register int sum = 0;
+  u_short answer = 0;
+  while (nleft > 1) { sum += *w++; nleft -= 2; }
+  if (nleft == 1) { *(u_char *) (&answer) = *(u_char *) w; sum += answer; }
+  sum = (sum >> 16) + (sum & 0xffff);   /* add hi 16 to low 16 */
+  sum += (sum >> 16);           /* add carry */
+  answer = ~sum;                /* truncate to 16 bits */
+  return (answer);
+}