Drop looped packets.

diff --git a/src/mctap.c b/src/mctap.c
index 9d183f9..24efc12 100644 (file)
--- a/src/mctap.c
+++ b/src/mctap.c
@@ -17,6 +17,7 @@
 #include "utils.h"
 
 static int quit = 0;
+static unsigned char macaddr[6];
 
 static void usage(FILE *out)
 {
@@ -145,6 +146,8 @@ static void bridge(int sock, int tap, struct sockaddr *dst, socklen_t dstlen)
            } else {
                if(sizeof(buf) - ret < sizeof(pi)) {
                    /* Drop */
+               } else if((ret < 12) || !memcmp(macaddr, buf + 6, 6)) {
+                   /* Drop looped back */
                } else {
                    memmove(buf + sizeof(pi), buf, ret);
                    pi.flags = 0;
@@ -189,6 +192,9 @@ static int maketap(char *name)
     strncpy(rb.ifr_name, name, IFNAMSIZ);
     if(ioctl(fd, TUNSETIFF, &rb))
        return(-1);
+    if(ioctl(fd, SIOCGIFHWADDR, &rb))
+       return(-1);
+    memcpy(macaddr, rb.ifr_hwaddr.sa_data, 6);
     return(fd);
 }
 
@@ -308,6 +314,7 @@ int main(int argc, char **argv)
     dst.sin_family = AF_INET;
     dst.sin_addr = group;
     dst.sin_port = htons(port);
+    syslog(LOG_INFO, "bridge created with MAC %02x:%02x:%02x:%02x:%02x:%02x", macaddr[0], macaddr[1], macaddr[2], macaddr[3], macaddr[4], macaddr[5]);
     bridge(sock, tap, (struct sockaddr *)&dst, sizeof(dst));
     syslog(LOG_INFO, "exiting");