Add in another magic number, reserved for Francisco Mesquita

<[email protected]>.

Rename the Kuznetzov magic to note what it is, and add and expand some
comments.

diff --git a/savefile.c b/savefile.c
index b6db6d87e7eac4830f4e4d1852cc9061af8bb114..6821b2f864e7e06cbbb854036d0e085062ca058c 100644 (file)
--- a/savefile.c
+++ b/savefile.c
@@ -30,7 +30,7 @@
 
 #ifndef lint
 static const char rcsid[] _U_ =
-    "@(#) $Header: /tcpdump/master/libpcap/savefile.c,v 1.107 2004-06-07 20:00:08 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/savefile.c,v 1.108 2004-08-17 17:50:33 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -49,8 +49,21 @@ static const char rcsid[] _U_ =
 #include "os-proto.h"
 #endif
 
-#define TCPDUMP_MAGIC 0xa1b2c3d4
-#define PATCHED_TCPDUMP_MAGIC 0xa1b2cd34
+/*
+ * Standard libpcap format.
+ */
+#define TCPDUMP_MAGIC          0xa1b2c3d4
+
+/*
+ * Alexey Kuznetzov's modified libpcap format.
+ */
+#define KUZNETZOV_TCPDUMP_MAGIC        0xa1b2cd34
+
+/*
+ * Reserved for Francisco Mesquita <[email protected]>
+ * for another modified format.
+ */
+#define FMESQUITA_TCPDUMP_MAGIC        0xa1b234cd
 
 /*
  * We use the "receiver-makes-right" approach to byte order,
@@ -636,9 +649,9 @@ pcap_open_offline(const char *fname, char *errbuf)
                goto bad;
        }
        magic = hdr.magic;
-       if (magic != TCPDUMP_MAGIC && magic != PATCHED_TCPDUMP_MAGIC) {
+       if (magic != TCPDUMP_MAGIC && magic != KUZNETZOV_TCPDUMP_MAGIC) {
                magic = SWAPLONG(magic);
-               if (magic != TCPDUMP_MAGIC && magic != PATCHED_TCPDUMP_MAGIC) {
+               if (magic != TCPDUMP_MAGIC && magic != KUZNETZOV_TCPDUMP_MAGIC) {
                        snprintf(errbuf, PCAP_ERRBUF_SIZE,
                            "bad dump file format");
                        goto bad;
@@ -646,12 +659,23 @@ pcap_open_offline(const char *fname, char *errbuf)
                p->sf.swapped = 1;
                swap_hdr(&hdr);
        }
-       if (magic == PATCHED_TCPDUMP_MAGIC) {
+       if (magic == KUZNETZOV_TCPDUMP_MAGIC) {
                /*
                 * XXX - the patch that's in some versions of libpcap
-                * changes the packet header but not the magic number;
+                * changes the packet header but not the magic number,
+                * and some other versions with this magic number have
+                * some extra debugging information in the packet header;
                 * we'd have to use some hacks^H^H^H^H^Hheuristics to
-                * detect that.
+                * detect those variants.
+                *
+                * Ethereal does that, but it does so by trying to read
+                * the first two packets of the file with each of the
+                * record header formats.  That currently means it seeks
+                * backwards and retries the reads, which doesn't work
+                * on pipes.  We want to be able to read from a pipe, so
+                * that strategy won't work; we'd have to buffer some
+                * data ourselves and read from that buffer in order to
+                * make that work.
                 */
                p->sf.hdrsize = sizeof(struct pcap_sf_patched_pkthdr);
        } else