$OpenBSD: patch-tcpdump_c,v 1.3 2011/08/25 22:40:21 bluhm Exp $
--- tcpdump.c.orig	Thu Oct  7 22:07:30 2004
+++ tcpdump.c	Sun May 22 22:54:01 2011
@@ -189,6 +189,22 @@ static int callback(
 	memcpy((char*)ip_buf,buf+8,iplen-8);
 	callback_plast = ip_buf+iplen-8-1;
 	break;
+      case PCAP_DLT_LOOP:
+	/* loopback type (af header) */
+	switch (ntohl(*(u_int *)buf)) {
+	case AF_INET:
+		eth_header.ether_type = htons(ETHERTYPE_IP);
+		break;
+	case AF_INET6:
+		eth_header.ether_type = htons(ETHERTYPE_IPV6);
+		break;
+	default:
+		eth_header.ether_type = 0;
+	}
+	offset = 4;
+	memcpy((char *)ip_buf,buf+offset,iplen-offset);
+	callback_plast = ip_buf+iplen-offset-1;
+	break;
       case PCAP_DLT_RAW:
 	/* raw IP */
 	offset = 0;
@@ -363,6 +379,9 @@ pread_f *is_tcpdump(char *filename)
       case PCAP_DLT_ATM_RFC1483:
 	eth_header.ether_type = htons(ETHERTYPE_IP);
 	physname = "ATM, LLC/SNAP encapsulated";
+	break;
+      case PCAP_DLT_LOOP:
+	physname = "LOOP";
 	break;
       case PCAP_DLT_RAW:
 	eth_header.ether_type = htons(ETHERTYPE_IP);