* Routines for the Generic Routing Encapsulation (GRE) protocol
* Brad Robel-Forrest <brad.robel-forrest@watchguard.com>
*
- * $Id: packet-gre.c,v 1.3 1999/07/13 02:52:51 gram Exp $
+ * $Id: packet-gre.c,v 1.28 2000/11/19 02:00:02 guy 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-ipx.h"
+
+static int proto_gre = -1;
+static int hf_gre_proto = -1;
+
+static gint ett_gre = -1;
+static gint ett_gre_flags = -1;
/* bit positions for flags in header */
#define GH_B_C 0x8000
#define GH_B_VER 0x0007
#define GRE_PPP 0x880B
+#define GRE_IP 0x0800
+#define GRE_WCCP 0x883E
+#define GRE_IPX 0x8137
-static int calc_len(guint16, int);
static void add_flags_and_ver(proto_tree *, guint16, int, int);
-void
+static const value_string typevals[] = {
+ { GRE_PPP, "PPP" },
+ { GRE_IP, "IP" },
+ { GRE_WCCP, "WCCP"},
+ { GRE_IPX, "IPX"},
+ { 0, NULL }
+};
+
+static dissector_handle_t ip_handle;
+static dissector_handle_t ppp_handle;
+
+static 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;
+ tvbuff_t *next_tvb;
+
+ OLD_CHECK_DISPLAY_AS_DATA(proto_gre, pd, offset, fd, tree);
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 (fd->cap_len > offset && tree) {
- int is_ppp;
+ if (IS_DATA_IN_FRAME(offset) && tree) {
+ 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_text(tree, offset, calc_len(flags_and_ver, 1),
- "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_text(tree, offset, calc_len(flags_and_ver, 1),
- "Generic Routing Encapsulation");
- 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, NullTVB, 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_uint(gre_tree, hf_gre_proto, NullTVB, 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);
- proto_tree_add_text(gre_tree, offset, sizeof(checksum),
+ proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(checksum),
"Checksum: %u", checksum);
offset += sizeof(checksum);
}
if (flags_and_ver & GH_B_C || flags_and_ver & GH_B_R) {
guint16 rtoffset = pntohs(pd + offset);
- proto_tree_add_text(gre_tree, offset, sizeof(rtoffset),
+ proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(rtoffset),
"Offset: %u", rtoffset);
offset += sizeof(rtoffset);
}
guint16 callid;
paylen = pntohs(pd + offset);
- proto_tree_add_text(gre_tree, offset, sizeof(paylen),
+ proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(paylen),
"Payload length: %u", paylen);
offset += sizeof(paylen);
callid = pntohs(pd + offset);
- proto_tree_add_text(gre_tree, offset, sizeof(callid),
+ proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(callid),
"Call ID: %u", callid);
offset += sizeof(callid);
}
else {
guint32 key = pntohl(pd + offset);
- proto_tree_add_text(gre_tree, offset, sizeof(key),
+ proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(key),
"Key: %u", key);
offset += sizeof(key);
}
if (flags_and_ver & GH_B_S) {
guint32 seqnum = pntohl(pd + offset);
- proto_tree_add_text(gre_tree, offset, sizeof(seqnum),
+ proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(seqnum),
"Sequence number: %u", seqnum);
offset += sizeof(seqnum);
}
if (is_ppp && flags_and_ver & GH_P_A) {
guint32 acknum = pntohl(pd + offset);
- proto_tree_add_text(gre_tree, offset, sizeof(acknum),
+ proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(acknum),
"Acknowledgement number: %u", acknum);
offset += sizeof(acknum);
}
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, NullTVB, offset, sizeof(guint16),
+ "Address family: %u", sre_af);
+ offset += sizeof(guint16);
+ proto_tree_add_text(gre_tree, NullTVB, 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, NullTVB, 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:
+ old_call_dissector(ppp_handle, pd, offset, fd, tree);
break;
+ case GRE_IP:
+ old_call_dissector(ip_handle, pd, offset, fd, tree);
+ break;
+ case GRE_WCCP:
+ if (is_wccp2) {
+ proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(guint32), "WCCPv2 Data");
+ offset += 4;
+ }
+ old_call_dissector(ip_handle, pd, offset, fd, tree);
+ break;
+ case GRE_IPX:
+ next_tvb = tvb_create_from_top(offset);
+ dissect_ipx(next_tvb, &pi, tree);
+ break;
default:
- dissect_data(pd, offset, fd, gre_tree);
+ next_tvb = tvb_create_from_top(offset);
+ dissect_data(next_tvb, 0, &pi, 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) {
proto_tree * fv_tree;
int nbits = sizeof(flags_and_ver) * 8;
- ti = proto_tree_add_text(tree, offset, 2,
- "Flags and version: %#08x", flags_and_ver);
- fv_tree = proto_item_add_subtree(ti, ETT_GRE_FLAGS);
+ ti = proto_tree_add_text(tree, NullTVB, offset, 2,
+ "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",
+ proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s",
decode_boolean_bitfield(flags_and_ver, GH_B_C, nbits,
"Checksum", "No checksum"));
- proto_tree_add_text(fv_tree, offset, sizeof(flags_and_ver), "%s",
+ proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s",
decode_boolean_bitfield(flags_and_ver, GH_B_R, nbits,
"Routing", "No routing"));
- proto_tree_add_text(fv_tree, offset, sizeof(flags_and_ver), "%s",
+ proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s",
decode_boolean_bitfield(flags_and_ver, GH_B_K, nbits,
"Key", "No key"));
- proto_tree_add_text(fv_tree, offset, sizeof(flags_and_ver), "%s",
+ proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s",
decode_boolean_bitfield(flags_and_ver, GH_B_S, nbits,
"Sequence number", "No sequence number"));
- proto_tree_add_text(fv_tree, offset, sizeof(flags_and_ver), "%s",
+ proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s",
decode_boolean_bitfield(flags_and_ver, GH_B_s, nbits,
"Strict source route", "No strict source route"));
- proto_tree_add_text(fv_tree, offset, sizeof(flags_and_ver), "%s",
+ proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s",
decode_numeric_bitfield(flags_and_ver, GH_B_RECUR, nbits,
"Recursion control: %u"));
if (is_ppp) {
- proto_tree_add_text(fv_tree, offset, sizeof(flags_and_ver), "%s",
+ proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s",
decode_boolean_bitfield(flags_and_ver, GH_P_A, nbits,
"Acknowledgment number", "No acknowledgment number"));
- proto_tree_add_text(fv_tree, offset, sizeof(flags_and_ver), "%s",
+ proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s",
decode_numeric_bitfield(flags_and_ver, GH_P_FLAGS, nbits,
"Flags: %u"));
}
else {
- proto_tree_add_text(fv_tree, offset, sizeof(flags_and_ver), "%s",
+ proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s",
decode_numeric_bitfield(flags_and_ver, GH_R_FLAGS, nbits,
"Flags: %u"));
}
- proto_tree_add_text(fv_tree, offset, sizeof(flags_and_ver), "%s",
+ proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s",
decode_numeric_bitfield(flags_and_ver, GH_B_VER, nbits,
"Version: %u"));
}
+void
+proto_register_gre(void)
+{
+ 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_subtree_array(ett, array_length(ett));
+}
+
+void
+proto_reg_handoff_gre(void)
+{
+ old_dissector_add("ip.proto", IP_PROTO_GRE, dissect_gre);
+
+ /*
+ * Get handles for the IP and PPP dissectors.
+ */
+ ip_handle = find_dissector("ip");
+ ppp_handle = find_dissector("ppp");
+}
git.samba.org / obnox / wireshark / wip.git / blobdiff