* Routines for the Generic Routing Encapsulation (GRE) protocol
* Brad Robel-Forrest <brad.robel-forrest@watchguard.com>
*
- * $Id: packet-gre.c,v 1.7 1999/11/16 11:42:31 guy Exp $
+ * $Id: packet-gre.c,v 1.17 2000/03/27 17:53:19 gram Exp $
*
* Ethereal - Network traffic analyzer
- * By Gerald Combs <gerald@unicom.net>
+ * By Gerald Combs <gerald@zing.org>
* Copyright 1998 Gerald Combs
*
*
#endif
#include <glib.h>
#include "packet.h"
+#include "packet-ip.h"
+#include "packet-ppp.h"
static int proto_gre = -1;
+static int hf_gre_proto = -1;
static gint ett_gre = -1;
static gint ett_gre_flags = -1;
#define GH_B_VER 0x0007
#define GRE_PPP 0x880B
+#define GRE_IP 0x0800
+#define GRE_WCCP 0x883E
-static int calc_len(guint16, int);
static void add_flags_and_ver(proto_tree *, guint16, int, int);
+static const value_string typevals[] = {
+ { GRE_PPP, "PPP" },
+ { GRE_IP, "IP" },
+ { GRE_WCCP, "WCCP"},
+ { 0, NULL }
+};
+
void
dissect_gre(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
guint16 flags_and_ver = pntohs(pd + offset);
guint16 type = pntohs(pd + offset + sizeof(flags_and_ver));
- static const value_string typevals[] = {
- { GRE_PPP, "PPP" },
- { 0, NULL }
- };
+ guint16 sre_af;
+ guint8 sre_length;
if (check_col(fd, COL_PROTOCOL))
col_add_str(fd, COL_PROTOCOL, "GRE");
if (check_col(fd, COL_INFO)) {
- if (type == GRE_PPP)
- col_add_str(fd, COL_INFO, "Encapsulated PPP");
- else
- col_add_str(fd, COL_INFO, "Encapsulated unknown");
+ col_add_fstr(fd, COL_INFO, "Encapsulated %s",
+ val_to_str(type, typevals, "0x%04X (unknown)"));
}
if (IS_DATA_IN_FRAME(offset) && tree) {
- int is_ppp;
+ gboolean is_ppp = FALSE;
+ gboolean is_wccp2 = FALSE;
proto_item * ti;
proto_tree * gre_tree;
+ guint len = 4;
- if (type == GRE_PPP) {
- is_ppp = 1;
- ti = proto_tree_add_item_format(tree, proto_gre, offset, calc_len(flags_and_ver, 1),
- NULL, "Generic Routing Encapsulation (PPP)");
- gre_tree = proto_item_add_subtree(ti, ett_gre);
- add_flags_and_ver(gre_tree, flags_and_ver, offset, 1);
- }
- else {
- is_ppp = 0;
- ti = proto_tree_add_item(tree, proto_gre, offset, calc_len(flags_and_ver, 1), NULL);
- gre_tree = proto_item_add_subtree(ti, ett_gre);
- add_flags_and_ver(gre_tree, flags_and_ver, offset, 0);
+ if (flags_and_ver & GH_B_C || flags_and_ver & GH_B_R)
+ len += 4;
+ if (flags_and_ver & GH_B_K)
+ len += 4;
+ if (flags_and_ver & GH_B_S)
+ len += 4;
+ switch (type) {
+
+ case GRE_PPP:
+ if (flags_and_ver & GH_P_A)
+ len += 4;
+ is_ppp = TRUE;
+ break;
+
+ case GRE_WCCP:
+ /* WCCP2 apparently puts an extra 4 octets into the header, but uses
+ the same encapsulation type; if it looks as if the first octet of
+ the packet isn't the beginning of an IPv4 header, assume it's
+ WCCP2. */
+ if ((pd[offset + sizeof(flags_and_ver) + sizeof(type)] & 0xF0) != 0x40) {
+ len += 4;
+ is_wccp2 = TRUE;
+ }
+ break;
}
+ ti = proto_tree_add_protocol_format(tree, proto_gre, offset, len,
+ "Generic Routing Encapsulation (%s)",
+ val_to_str(type, typevals, "0x%04X - unknown"));
+ gre_tree = proto_item_add_subtree(ti, ett_gre);
+ add_flags_and_ver(gre_tree, flags_and_ver, offset, is_ppp);
+
offset += sizeof(flags_and_ver);
- proto_tree_add_text(gre_tree, offset, sizeof(type),
- "Protocol Type: %s (%#04x)",
- val_to_str(type, typevals, "Unknown"), type);
- offset += sizeof(type);
+ proto_tree_add_item(gre_tree, hf_gre_proto, offset, sizeof(type), type);
+ offset += sizeof(type);
if (flags_and_ver & GH_B_C || flags_and_ver & GH_B_R) {
guint16 checksum = pntohs(pd + offset);
}
if (flags_and_ver & GH_B_R) {
- proto_tree_add_text(gre_tree, offset, sizeof(guint16),
- "Address family: %u", pntohs(pd + offset));
- offset += sizeof(guint16);
- proto_tree_add_text(gre_tree, offset, 1,
+ for (;;) {
+ sre_af = pntohs(pd + offset);
+ proto_tree_add_text(gre_tree, offset, sizeof(guint16),
+ "Address family: %u", sre_af);
+ offset += sizeof(guint16);
+ proto_tree_add_text(gre_tree, offset, 1,
"SRE offset: %u", pd[offset++]);
- proto_tree_add_text(gre_tree, offset, 1,
- "SRE length: %u", pd[offset++]);
+ sre_length = pd[offset];
+ proto_tree_add_text(gre_tree, offset, sizeof(guint8),
+ "SRE length: %u", sre_length);
+ offset += sizeof(guint8);
+ if (sre_af == 0 && sre_length == 0)
+ break;
+ offset += sre_length;
+ }
}
switch (type) {
- case GRE_PPP:
- dissect_payload_ppp(pd, offset, fd, tree);
+ case GRE_PPP:
+ dissect_ppp(pd, offset, fd, tree);
break;
+ case GRE_IP:
+ dissect_ip(pd, offset, fd, tree);
+ break;
+ case GRE_WCCP:
+ if (is_wccp2) {
+ proto_tree_add_text(gre_tree, offset, sizeof(guint32), "WCCPv2 Data");
+ offset += 4;
+ }
+ dissect_ip(pd, offset, fd, tree);
+ break;
default:
dissect_data(pd, offset, fd, gre_tree);
+ break;
}
}
}
-static int
-calc_len(guint16 flags_and_ver, int is_ppp) {
-
- int len = 4;
-
- if (flags_and_ver & GH_B_C || flags_and_ver & GH_B_R) len += 4;
- if (flags_and_ver & GH_B_K) len += 4;
- if (flags_and_ver & GH_B_S) len += 4;
- if (is_ppp && flags_and_ver & GH_P_A) len += 4;
-
- return len;
-}
-
static void
add_flags_and_ver(proto_tree *tree, guint16 flags_and_ver, int offset, int is_ppp) {
int nbits = sizeof(flags_and_ver) * 8;
ti = proto_tree_add_text(tree, offset, 2,
- "Flags and version: %#08x", flags_and_ver);
+ "Flags and version: %#04x", flags_and_ver);
fv_tree = proto_item_add_subtree(ti, ett_gre_flags);
proto_tree_add_text(fv_tree, offset, sizeof(flags_and_ver), "%s",
void
proto_register_gre(void)
{
-/* static hf_register_info hf[] = {
- { &variable,
- { "Name", "gre.abbreviation", TYPE, VALS_POINTER }},
- };*/
+ static hf_register_info hf[] = {
+ { &hf_gre_proto,
+ { "Protocol Type", "gre.proto", FT_UINT16, BASE_HEX, VALS(typevals), 0x0,
+ "The protocol that is GRE encapsulated"}
+ },
+ };
static gint *ett[] = {
&ett_gre,
+ &ett_gre_flags,
};
proto_gre = proto_register_protocol("Generic Routing Encapsulation", "gre");
- /* proto_register_field_array(proto_gre, hf, array_length(hf));*/
+ proto_register_field_array(proto_gre, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
git.samba.org / obnox / wireshark / wip.git / blobdiff