The payload of an SCTP DATA chunk is *not* necessarily ASCII text, so it

[tcpdump] / print-null.c

diff --git a/print-null.c b/print-null.c
index 8e43bb5dcba8c566590ab97405047cd2eddac2fc..30724ec68305b7b9fbb7cdc49ad7cd83fb538c72 100644 (file)
--- a/print-null.c
+++ b/print-null.c
@@ -21,7 +21,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-null.c,v 1.38 2000-10-07 05:53:13 itojun Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/tcpdump/print-null.c,v 1.41 2001-07-05 18:54:15 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -56,53 +56,79 @@ struct rtentry;
 #endif
 
 /*
- * The DLT_NULL packet header is 4 bytes long. It contains a network
- * order 32 bit integer that specifies the family, e.g. AF_INET
+ * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order
+ * 32-bit integer that specifies the family, e.g. AF_INET.
+ *
+ * Note here that "host" refers to the host on which the packets were
+ * captured; that isn't necessarily *this* host.
+ *
+ * The OpenBSD DLT_LOOP packet header is the same, except that the integer
+ * is in network byte order.
  */
 #define        NULL_HDRLEN 4
 
 static void
-null_print(const u_char *p, const struct ip *ip, u_int length)
+null_print(u_int family, u_int length)
 {
-       u_int family;
+       if (nflag)
+               printf("AF %u ", family);
+       else {
+               switch (family) {
 
-       memcpy((char *)&family, (char *)p, sizeof(family));
-
-       if (nflag) {
-               /* XXX just dump the header */
-               return;
-       }
-       switch (family) {
-
-       case AF_INET:
-               printf("ip: ");
-               break;
+               case AF_INET:
+                       printf("ip ");
+                       break;
 
 #ifdef INET6
-       case AF_INET6:
-               printf("ip6: ");
-               break;
+               case AF_INET6:
+                       printf("ip6 ");
+                       break;
 #endif
 
-       case AF_NS:
-               printf("ns: ");
-               break;
+               case AF_NS:
+                       printf("ns ");
+                       break;
 
-       default:
-               printf("AF %d: ", family);
-               break;
+               default:
+                       printf("AF %u ", family);
+                       break;
+               }
        }
+       printf("%d: ", length);
 }
 
+/*
+ * Byte-swap a 32-bit number.
+ * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
+ * big-endian platforms.)
+ */
+#define        SWAPLONG(y) \
+((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
+
 void
 null_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
 {
        u_int length = h->len;
        u_int caplen = h->caplen;
        const struct ip *ip;
+       u_int family;
 
+       ++infodelay;
        ts_print(&h->ts);
 
+       memcpy((char *)&family, (char *)p, sizeof(family));
+
+       /*
+        * This isn't necessarily in our host byte order; if this is
+        * a DLT_LOOP capture, it's in network byte order, and if
+        * this is a DLT_NULL capture from a machine with the opposite
+        * byte-order, it's in the opposite byte order from ours.
+        *
+        * If the upper 16 bits aren't all zero, assume it's byte-swapped.
+        */
+       if ((family & 0xFFFF0000) != 0)
+               family = SWAPLONG(family);
+
        /*
         * Some printers want to get back at the link level addresses,
         * and/or check that they're not walking off the end of the packet.
@@ -116,7 +142,7 @@ null_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
        ip = (struct ip *)(p + NULL_HDRLEN);
 
        if (eflag)
-               null_print(p, ip, length);
+               null_print(family, length);
 
        switch (IP_V(ip)) {
        case 4:
@@ -135,5 +161,8 @@ null_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
        if (xflag)
                default_print((const u_char *)ip, caplen - NULL_HDRLEN);
        putchar('\n');
+       --infodelay;
+       if (infoprint)
+               info(0);
 }