VPP: add vpp graph dispatch trace dissector

Add a dissector for http://fd.io vpp graph dispatch traces. The file
format is described in detail here:
       https://fdio-vpp.readthedocs.io/en/latest/gettingstarted\
               /developers/vnet.html#graph-dispatcher-pcap-tracing

Fuzz-tested with good results.

Bug: 15411
Change-Id: I3b040bb072ce43fb2fb646a9e473c5486654906a
Signed-off-by: Dave Barach <dave@barachs.net>
Reviewed-on: https://code.wireshark.org/review/31466
Petri-Dish: Guy Harris <guy@alum.mit.edu>
Tested-by: Petri Dish Buildbot
Reviewed-by: Guy Harris <guy@alum.mit.edu>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

5 files changed, 499 insertions, 0 deletions

diff --git a/epan/dissectors/CMakeLists.txt b/epan/dissectors/CMakeLists.txt
index 48ebeafc65..18c48bbffb 100644
--- a/epan/dissectors/CMakeLists.txt
+++ b/epan/dissectors/CMakeLists.txt
@@ -1821,6 +1821,7 @@ set(DISSECTOR_SRC
 	${CMAKE_CURRENT_SOURCE_DIR}/packet-vnc.c
 	${CMAKE_CURRENT_SOURCE_DIR}/packet-vntag.c
 	${CMAKE_CURRENT_SOURCE_DIR}/packet-vp8.c
+	${CMAKE_CURRENT_SOURCE_DIR}/packet-vpp.c
 	${CMAKE_CURRENT_SOURCE_DIR}/packet-vrrp.c
 	${CMAKE_CURRENT_SOURCE_DIR}/packet-vrt.c
 	${CMAKE_CURRENT_SOURCE_DIR}/packet-vsip.c
diff --git a/epan/dissectors/packet-vpp.c b/epan/dissectors/packet-vpp.c
new file mode 100644
index 0000000000..c580974db6
--- /dev/null
+++ b/epan/dissectors/packet-vpp.c
@@ -0,0 +1,491 @@
+/* packet-vpp.c
+ *
+ * Routines for the disassembly of fd.io vpp project
+ * dispatch captures
+ *
+ * Copyright 2019, Dave Barach <wireshark@barachs.net>
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "config.h"
+
+#include <epan/packet.h>
+#include <epan/expert.h>
+#include <epan/to_str.h>
+#include <epan/in_cksum.h>
+#include <epan/nlpid.h>
+#include <epan/etypes.h>
+#include <stdio.h>
+#include <wsutil/ws_printf.h>
+
+void proto_register_vpp(void);
+void proto_reg_handoff_vpp(void);
+
+static int proto_vpp = -1;
+static int proto_vpp_metadata = -1;
+static int proto_vpp_opaque = -1;
+static int proto_vpp_opaque2 = -1;
+static int proto_vpp_trace = -1;
+static int hf_vpp_nodename = -1;
+static int hf_vpp_metadata = -1;
+static int hf_vpp_buffer_index = -1;
+static int hf_vpp_buffer_opaque = -1;
+static int hf_vpp_buffer_opaque2 = -1;
+static int hf_vpp_buffer_trace = -1;
+static int hf_vpp_major_version = -1;
+static int hf_vpp_minor_version = -1;
+static int hf_vpp_protocol_hint = -1;
+
+static expert_module_t* expert_vpp;
+
+static expert_field ei_vpp_major_version_error = EI_INIT;
+static expert_field ei_vpp_minor_version_error = EI_INIT;
+static expert_field ei_vpp_protocol_hint_error = EI_INIT;
+
+static gint ett_vpp = -1;
+static gint ett_vpp_opaque = -1;
+static gint ett_vpp_opaque2 = -1;
+static gint ett_vpp_metadata = -1;
+static gint ett_vpp_trace = -1;
+
+static dissector_handle_t vpp_dissector_handle;
+static dissector_handle_t vpp_opaque_dissector_handle;
+static dissector_handle_t vpp_opaque2_dissector_handle;
+static dissector_handle_t vpp_metadata_dissector_handle;
+static dissector_handle_t vpp_trace_dissector_handle;
+
+#define VPP_MAJOR_VERSION       1
+#define VPP_MINOR_VERSION       0
+#define IP4_TYPICAL_VERSION_LENGTH      0x45
+#define IP6_TYPICAL_VERSION_AND_TRAFFIC_CLASS   0x60
+
+typedef enum
+  {
+    VLIB_NODE_PROTO_HINT_NONE = 0,
+    VLIB_NODE_PROTO_HINT_ETHERNET,
+    VLIB_NODE_PROTO_HINT_IP4,
+    VLIB_NODE_PROTO_HINT_IP6,
+    VLIB_NODE_PROTO_HINT_TCP,
+    VLIB_NODE_PROTO_HINT_UDP,
+    VLIB_NODE_N_PROTO_HINTS,
+  } vlib_node_proto_hint_t;
+
+static dissector_handle_t next_dissectors[VLIB_NODE_N_PROTO_HINTS];
+
+/* List of next dissectors hints that we know about */
+#define foreach_next_dissector                          \
+_(VLIB_NODE_PROTO_HINT_ETHERNET, eth_withoutfcs)        \
+_(VLIB_NODE_PROTO_HINT_IP4, ip)                         \
+_(VLIB_NODE_PROTO_HINT_IP6, ipv6)                       \
+_(VLIB_NODE_PROTO_HINT_TCP, tcp)                        \
+_(VLIB_NODE_PROTO_HINT_UDP, udp)
+
+static void
+add_multi_line_string_to_tree(proto_tree *tree, tvbuff_t *tvb, gint start,
+                              gint len, int hf)
+{
+    gint next;
+    int line_len;
+    int data_len;
+
+    while(len > 0) {
+        line_len = tvb_find_line_end(tvb, start, len, &next, FALSE);
+        data_len = next - start;
+        proto_tree_add_string(tree, hf, tvb, start, data_len,
+                              tvb_format_stringzpad(tvb, start, line_len));
+        start += data_len;
+        len -= data_len;
+    }
+}
+
+static int
+dissect_vpp_metadata(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
+                     void* data _U_)
+{
+    int offset = 0;
+    proto_item *ti;
+    proto_tree *metadata_tree;
+    gint metadata_string_length;
+
+    col_set_str(pinfo->cinfo, COL_PROTOCOL, "VPP-Metadata");
+    col_clear(pinfo->cinfo, COL_INFO);
+
+    ti = proto_tree_add_item(tree, proto_vpp_metadata, tvb, offset, -1, ENC_NA);
+    metadata_tree = proto_item_add_subtree(ti, ett_vpp_metadata);
+
+    /* How long is the metadata string? */
+    metadata_string_length = tvb_strsize(tvb, offset);
+
+    add_multi_line_string_to_tree(metadata_tree, tvb, 0,
+                                  metadata_string_length,
+                                  hf_vpp_metadata);
+    return tvb_captured_length(tvb);
+}
+
+static int
+dissect_vpp_trace(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
+                  void* data _U_)
+{
+    int offset = 0;
+    proto_item *ti;
+    proto_tree *trace_tree;
+    gint trace_string_length;
+
+    col_set_str(pinfo->cinfo, COL_PROTOCOL, "VPP-Trace");
+    col_clear(pinfo->cinfo, COL_INFO);
+
+    ti = proto_tree_add_item(tree, proto_vpp_trace, tvb, offset, -1, ENC_NA);
+    trace_tree = proto_item_add_subtree(ti, ett_vpp_trace);
+
+    /* How long is the trace string? */
+    trace_string_length = tvb_strsize(tvb, offset);
+
+    add_multi_line_string_to_tree(trace_tree, tvb, 0,
+                                  trace_string_length,
+                                  hf_vpp_buffer_trace);
+    return tvb_captured_length(tvb);
+}
+
+
+static int
+dissect_vpp_opaque(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
+                   void* data _U_)
+{
+    int offset = 0;
+    proto_item *ti;
+    proto_tree *opaque_tree;
+    gint opaque_string_length;
+
+    col_set_str(pinfo->cinfo, COL_PROTOCOL, "VPP-Opaque");
+    col_clear(pinfo->cinfo, COL_INFO);
+
+    ti = proto_tree_add_item(tree, proto_vpp_opaque, tvb, offset, -1, ENC_NA);
+    opaque_tree = proto_item_add_subtree(ti, ett_vpp_opaque);
+
+    opaque_string_length = tvb_strsize(tvb, offset);
+    add_multi_line_string_to_tree(opaque_tree, tvb, 0, opaque_string_length,
+                                  hf_vpp_buffer_opaque);
+
+    return tvb_captured_length(tvb);
+}
+
+static int
+dissect_vpp_opaque2(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
+                    void* data _U_)
+{
+    int offset = 0;
+    proto_item *ti;
+    proto_tree *opaque2_tree;
+    gint opaque2_string_length;
+
+    col_set_str(pinfo->cinfo, COL_PROTOCOL, "VPP-Opaque2");
+    col_clear(pinfo->cinfo, COL_INFO);
+
+    ti = proto_tree_add_item(tree, proto_vpp_opaque2, tvb, offset, -1, ENC_NA);
+    opaque2_tree = proto_item_add_subtree(ti, ett_vpp_opaque2);
+
+    opaque2_string_length = tvb_strsize(tvb, offset);
+    add_multi_line_string_to_tree(opaque2_tree, tvb, 0, opaque2_string_length,
+                                  hf_vpp_buffer_opaque2);
+
+    return tvb_captured_length(tvb);
+}
+
+
+static int
+dissect_vpp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
+{
+    proto_item *ti;
+    proto_tree *vpp_tree;
+    tvbuff_t *metadata_tvb, *opaque_tvb, *opaque2_tvb, *eth_tvb, *trace_tvb;
+    int offset = 0;
+    guint8 major_version, minor_version, string_count, protocol_hint;
+    guint8 *name;
+    guint len;
+    guint8 maybe_protocol_id;
+    dissector_handle_t use_this_dissector;
+
+    col_set_str(pinfo->cinfo, COL_PROTOCOL, "VPP");
+    col_clear(pinfo->cinfo, COL_INFO);
+
+    ti = proto_tree_add_item(tree, proto_vpp, tvb, offset, -1, ENC_NA);
+    vpp_tree = proto_item_add_subtree(ti, ett_vpp);
+
+    major_version = tvb_get_guint8(tvb, offset);
+    /* If the major version doesn't match, quit on the spot */
+    if(major_version != VPP_MAJOR_VERSION) {
+        proto_item *major_version_item;
+        major_version_item =
+            proto_tree_add_item(tree, hf_vpp_major_version,
+                                tvb, offset, 1, ENC_NA);
+        expert_add_info_format(pinfo, major_version_item,
+                               &ei_vpp_major_version_error,
+                               "Major Version Mismatch read %d not %d",
+                               (int)major_version, VPP_MAJOR_VERSION);
+        return tvb_captured_length(tvb);
+    }
+    offset++;
+
+    minor_version = tvb_get_guint8(tvb, offset);
+    /* If the minor version doesn't match, make a note and try to continue */
+    if(minor_version != VPP_MINOR_VERSION) {
+        proto_item *minor_version_item;
+        minor_version_item =
+            proto_tree_add_item(tree, hf_vpp_minor_version,
+                                tvb, offset, 1, ENC_NA);
+        expert_add_info_format(pinfo, minor_version_item,
+                               &ei_vpp_minor_version_error,
+                               "Minor Version Mismatch read %d not %d",
+                               (int)minor_version, VPP_MINOR_VERSION);
+    }
+    offset++;
+
+    /* Number of counted strings in this trace record */
+    string_count = tvb_get_guint8(tvb, offset);
+    offset++;
+
+    /*
+     * Hint: protocol which should be at b->data[b->current_data]
+     * It will be a while before vpp sends useful hints for every
+     * possible node, see heuristic below.
+     */
+    protocol_hint = tvb_get_guint8(tvb, offset);
+
+    if(protocol_hint >= array_length(next_dissectors)) {
+        proto_item *protocol_hint_item;
+        protocol_hint_item =
+            proto_tree_add_item(tree, hf_vpp_protocol_hint,
+                                tvb, offset, 1, ENC_NA);
+        expert_add_info_format(pinfo, protocol_hint_item,
+                               &ei_vpp_protocol_hint_error,
+                               "Protocol hint %d out of range, max %d",
+                               (int)protocol_hint,
+                               (int)array_length(next_dissectors));
+        protocol_hint = 0;
+    }
+
+    offset++;
+
+    /* Buffer Index */
+    proto_tree_add_item(vpp_tree, hf_vpp_buffer_index, tvb,
+                        offset, 4, ENC_BIG_ENDIAN);
+    offset += 4;
+
+    /* Nodename */
+    len = tvb_strsize(tvb, offset);
+    name = tvb_get_string_enc(wmem_packet_scope(), tvb, offset, len,
+                              ENC_ASCII);
+    proto_tree_add_string(tree, hf_vpp_nodename, tvb, offset, len, name);
+    offset += len;
+
+    /* Metadata */
+    len = tvb_strsize(tvb, offset);
+    metadata_tvb = tvb_new_subset_remaining(tvb, offset);
+    call_dissector(vpp_metadata_dissector_handle, metadata_tvb, pinfo, tree);
+    offset += len;
+
+    /* Opaque */
+    len = tvb_strsize(tvb, offset);
+    opaque_tvb = tvb_new_subset_remaining(tvb, offset);
+    call_dissector(vpp_opaque_dissector_handle, opaque_tvb, pinfo, tree);
+    offset += len;
+
+    /* Opaque2 */
+    len = tvb_strsize(tvb, offset);
+    opaque2_tvb = tvb_new_subset_remaining(tvb, offset);
+    call_dissector(vpp_opaque2_dissector_handle, opaque2_tvb, pinfo, tree);
+    offset += len;
+
+    /* Trace, if present */
+    if(string_count > 4) {
+        len = tvb_strsize(tvb, offset);
+        trace_tvb = tvb_new_subset_remaining(tvb, offset);
+        call_dissector(vpp_trace_dissector_handle, trace_tvb, pinfo, tree);
+        offset += len;
+    }
+
+    eth_tvb = tvb_new_subset_remaining(tvb, offset);
+
+    /*
+     * Delegate the rest of the packet dissection to the per-node
+     * next dissector in the foreach_node_to_dissector_pair list
+     *
+     * Failing that, pretend its an ethernet packet
+     */
+    /* See setup for hint == 0 below */
+    use_this_dissector = next_dissectors [protocol_hint];
+    if(protocol_hint == 0) {
+        maybe_protocol_id = tvb_get_guint8(tvb, offset);
+
+        switch(maybe_protocol_id) {
+        case IP4_TYPICAL_VERSION_LENGTH:
+            use_this_dissector = next_dissectors[VLIB_NODE_PROTO_HINT_IP4];
+            break;
+        case IP6_TYPICAL_VERSION_AND_TRAFFIC_CLASS:
+            use_this_dissector = next_dissectors[VLIB_NODE_PROTO_HINT_IP6];
+            break;
+        default:
+            break;
+        }
+    }
+    call_dissector(use_this_dissector, eth_tvb, pinfo, tree);
+    return tvb_captured_length(tvb);
+}
+
+void
+proto_register_vpp(void)
+{
+    static hf_register_info vpp_hf[] = {
+        { &hf_vpp_buffer_index,
+          { "BufferIndex", "vpp.BufferIndex",  FT_UINT32, BASE_HEX, NULL, 0x0,
+            NULL, HFILL },
+        },
+        { &hf_vpp_nodename,
+          { "NodeName", "vpp.NodeName",  FT_STRINGZ, BASE_NONE, NULL, 0x0,
+            NULL, HFILL },
+        },
+        { &hf_vpp_major_version,
+          { "MajorVersion", "vpp.MajorVersion",  FT_UINT8, BASE_DEC, NULL, 0x0,
+            NULL, HFILL },
+        },
+        { &hf_vpp_minor_version,
+          { "MinorVersion", "vpp.MinorVersion",  FT_UINT8, BASE_DEC, NULL, 0x0,
+            NULL, HFILL },
+        },
+        { &hf_vpp_protocol_hint,
+          { "ProtocolHint", "vpp.ProtocolHint",  FT_UINT8, BASE_DEC, NULL, 0x0,
+            NULL, HFILL },
+        },
+    };
+
+    static ei_register_info vpp_ei[] = {
+        { &ei_vpp_major_version_error,
+          { "vpp.bad_major_version", PI_MALFORMED, PI_ERROR,
+            "Bad Major Version", EXPFILL }},
+        { &ei_vpp_minor_version_error,
+          { "vpp.bad_minor_version", PI_UNDECODED, PI_WARN,
+            "Bad Minor Version", EXPFILL }},
+        { &ei_vpp_protocol_hint_error,
+          { "vpp.bad_protocol_hint", PI_PROTOCOL, PI_WARN,
+            "Bad Protocol Hint", EXPFILL }},
+    };
+
+    static hf_register_info metadata_hf[] = {
+        { &hf_vpp_metadata,
+          { "Metadata", "vpp.metadata",
+            FT_STRINGZ, BASE_NONE, NULL, 0x0, NULL, HFILL },
+        },
+    };
+
+    static hf_register_info opaque_hf[] = {
+        { &hf_vpp_buffer_opaque,
+          { "Opaque", "vpp.opaque",
+            FT_STRINGZ, BASE_NONE, NULL, 0x0, NULL, HFILL },
+        },
+    };
+
+    static hf_register_info opaque2_hf[] = {
+        { &hf_vpp_buffer_opaque2,
+          { "Opaque2", "vpp.opaque2",
+            FT_STRINGZ, BASE_NONE, NULL, 0x0, NULL, HFILL },
+        },
+    };
+
+    static hf_register_info trace_hf[] = {
+        { &hf_vpp_buffer_trace,
+          { "Trace", "vpp.trace",  FT_STRINGZ, BASE_NONE, NULL, 0x0,
+            NULL, HFILL },
+        },
+    };
+
+    static gint *vpp_ett[] = {
+        &ett_vpp,
+    };
+    static gint *ett_metadata[] = {
+        &ett_vpp_metadata,
+    };
+    static gint *ett_opaque[] = {
+        &ett_vpp_opaque,
+    };
+    static gint *ett_opaque2[] = {
+        &ett_vpp_opaque2,
+    };
+    static gint *ett_trace[] = {
+        &ett_vpp_trace,
+    };
+
+    proto_vpp = proto_register_protocol("VPP Dispatch Trace", "VPP", "vpp");
+    proto_register_field_array(proto_vpp, vpp_hf, array_length(vpp_hf));
+    proto_register_subtree_array(vpp_ett, array_length(vpp_ett));
+    register_dissector("vpp", dissect_vpp, proto_vpp);
+
+    expert_vpp = expert_register_protocol(proto_vpp);
+    expert_register_field_array(expert_vpp, vpp_ei, array_length(vpp_ei));
+
+    proto_vpp_metadata = proto_register_protocol("VPP Buffer Metadata",
+                                                 "VPP-Metadata",
+                                                 "vpp-metadata");
+    proto_register_field_array(proto_vpp_metadata, metadata_hf,
+                               array_length(metadata_hf));
+    proto_register_subtree_array(ett_metadata, array_length(ett_metadata));
+    register_dissector("vppMetadata", dissect_vpp_metadata, proto_vpp_metadata);
+
+    proto_vpp_opaque = proto_register_protocol("VPP Buffer Opaque", "VPP-Opaque",
+                                               "vpp-opaque");
+    proto_register_field_array(proto_vpp_opaque, opaque_hf,
+                               array_length(opaque_hf));
+    proto_register_subtree_array(ett_opaque, array_length(ett_opaque));
+    register_dissector("vppOpaque", dissect_vpp_opaque, proto_vpp_opaque);
+
+    proto_vpp_opaque2 = proto_register_protocol("VPP Buffer Opaque2",
+                                                "VPP-Opaque2", "vpp-opaque2");
+    proto_register_field_array(proto_vpp_opaque2, opaque2_hf,
+                               array_length(opaque2_hf));
+    proto_register_subtree_array(ett_opaque2, array_length(ett_opaque2));
+    register_dissector("vppOpaque2", dissect_vpp_opaque2, proto_vpp_opaque2);
+
+
+    proto_vpp_trace = proto_register_protocol("VPP Buffer Trace", "VPP-Trace",
+                                              "vpp-trace");
+    proto_register_field_array(proto_vpp_trace, trace_hf,
+                               array_length(trace_hf));
+    proto_register_subtree_array(ett_trace, array_length(ett_trace));
+    register_dissector("vppTrace", dissect_vpp_trace, proto_vpp_trace);
+
+#define _(idx,dname) next_dissectors[idx] = find_dissector(#dname);
+    foreach_next_dissector;
+#undef _
+
+    /* if all else fails, dissect data as if ethernet MAC */
+    next_dissectors[VLIB_NODE_PROTO_HINT_NONE] =
+        next_dissectors [VLIB_NODE_PROTO_HINT_ETHERNET];
+}
+
+void
+proto_reg_handoff_vpp(void)
+{
+    vpp_dissector_handle = find_dissector("vpp");
+    vpp_metadata_dissector_handle = find_dissector("vppMetadata");
+    vpp_opaque_dissector_handle = find_dissector("vppOpaque");
+    vpp_opaque2_dissector_handle = find_dissector("vppOpaque2");
+    vpp_trace_dissector_handle = find_dissector("vppTrace");
+    dissector_add_uint("wtap_encap", WTAP_ENCAP_VPP, vpp_dissector_handle);
+}
+
+/*
+ * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 4
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * vi: set shiftwidth=4 tabstop=8 expandtab:
+ * :indentSize=4:tabSize=8:noTabs=true:
+ */
diff --git a/wiretap/pcap-common.c b/wiretap/pcap-common.c
index 48c674723c..9f1d10da7a 100644
--- a/wiretap/pcap-common.c
+++ b/wiretap/pcap-common.c
@@ -467,6 +467,9 @@ static const struct {
 	/* Elektrobit High Speed Capture and Replay */
 	{ 279,		WTAP_ENCAP_EBHSCR },
 
+	/* VPP dispatch trace */
+	{ 280,		WTAP_ENCAP_VPP },
+
 	/*
 	 * To repeat:
 	 *
diff --git a/wiretap/wtap.c b/wiretap/wtap.c
index 53a06a0dad..b7498d337c 100644
--- a/wiretap/wtap.c
+++ b/wiretap/wtap.c
@@ -958,6 +958,9 @@ static struct encap_type_info encap_table_base[] = {
 
 	/* WTAP_ENCAP_EBHSCR */
 	{ "ebhscr", "Elektrobit High Speed Capture and Replay" },
+
+	/* WTAP_ENCAP_VPP */
+	{ "vpp", "Vector Packet Processing graph dispatch trace" },
 };
 
 WS_DLL_LOCAL
diff --git a/wiretap/wtap.h b/wiretap/wtap.h
index 0d6bd06972..2f907feae3 100644
--- a/wiretap/wtap.h
+++ b/wiretap/wtap.h
@@ -285,6 +285,7 @@ extern "C" {
 #define WTAP_ENCAP_RFC7468                      202
 #define WTAP_ENCAP_SYSTEMD_JOURNAL              203 /* Event, not a packet */
 #define WTAP_ENCAP_EBHSCR                       204
+#define WTAP_ENCAP_VPP                          205
 
 /* After adding new item here, please also add new item to encap_table_base array */