Adding upstream version 4.2.2.upstream/4.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 525 insertions, 0 deletions

diff --git a/epan/dissectors/packet-null.c b/epan/dissectors/packet-null.c
new file mode 100644
index 00000000..0ff004c7
--- /dev/null
+++ b/epan/dissectors/packet-null.c
@@ -0,0 +1,525 @@
+/* packet-null.c
+ * Routines for null packet disassembly
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ *
+ * This file created by Mike Hall <mlh@io.com>
+ * Copyright 1998
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "config.h"
+
+#include <wsutil/pint.h>
+
+#include <epan/packet.h>
+#include <epan/capture_dissectors.h>
+#include "packet-ip.h"
+#include "packet-ppp.h"
+#include <epan/etypes.h>
+#include <epan/aftypes.h>
+
+void proto_register_null(void);
+void proto_reg_handoff_null(void);
+
+static dissector_table_t null_dissector_table;
+static dissector_table_t ethertype_dissector_table;
+
+/* protocols and header fields */
+static int proto_null = -1;
+static int hf_null_etype = -1;
+static int hf_null_family = -1;
+
+static gint ett_null = -1;
+
+/* Null/loopback structs and definitions */
+
+/* Family values. */
+static const value_string family_vals[] = {
+  {BSD_AF_INET,          "IP"             },
+  {BSD_AF_ISO,           "OSI"            },
+  {BSD_AF_APPLETALK,     "Appletalk"      },
+  {BSD_AF_IPX,           "Netware IPX/SPX"},
+  {BSD_AF_INET6_BSD,     "IPv6"           },
+  {BSD_AF_INET6_FREEBSD, "IPv6"           },
+  {BSD_AF_INET6_DARWIN,  "IPv6"           },
+  {0,                    NULL             }
+};
+
+static dissector_handle_t null_handle, loop_handle;
+static capture_dissector_handle_t null_cap_handle;
+
+static dissector_handle_t ppp_hdlc_handle;
+static capture_dissector_handle_t ppp_hdlc_cap_handle;
+
+static gboolean
+capture_null( const guchar *pd, int offset _U_, int len, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header _U_ )
+{
+  guint32 null_header;
+
+  /*
+   * BSD drivers that use DLT_NULL - including the FreeBSD 3.2 ISDN-for-BSD
+   * drivers, as well as the 4.4-Lite and FreeBSD loopback drivers -
+   * stuff the AF_ value for the protocol, in *host* byte order, in the
+   * first four bytes.
+   *
+   * However, the IRIX and UNICOS/mp snoop socket mechanism supplies,
+   * on loopback devices, a 4-byte header that has a 2 byte (big-endian)
+   * AF_ value and 2 bytes of 0, so it's
+   *
+   *    0000AAAA
+   *
+   * when read on a little-endian machine and
+   *
+   *    AAAA0000
+   *
+   * when read on a big-endian machine.  The current CVS version of libpcap
+   * compensates for this by converting it to standard 4-byte format before
+   * processing the packet, but snoop captures from IRIX or UNICOS/mp
+   * have the 2-byte+2-byte header, as might tcpdump or libpcap captures
+   * with older versions of libpcap.
+   *
+   * AF_ values are small integers, and probably fit in 8 bits (current
+   * values on the BSDs do), and have their upper 24 bits zero.
+   * This means that, in practice, if you look at the header as a 32-bit
+   * integer in host byte order:
+   *
+   *    on a little-endian machine:
+   *
+   *            a little-endian DLT_NULL header looks like
+   *
+   *                    000000AA
+   *
+   *            a big-endian DLT_NULL header, or a DLT_LOOP header, looks
+   *            like
+   *
+   *                    AA000000
+   *
+   *            an IRIX or UNICOS/mp DLT_NULL header looks like
+   *
+   *                    0000AA00
+   *
+   *    on a big-endian machine:
+   *
+   *            a big-endian DLT_NULL header, or a DLT_LOOP header, looks
+   *            like
+   *
+   *                    000000AA
+   *
+   *            a little-endian DLT_NULL header looks like
+   *
+   *                    AA000000
+   *
+   *            an IRIX or UNICOS/mp DLT_NULL header looks like
+   *
+   *                    00AA0000
+   *
+   * However, according to Gerald Combs, a FreeBSD ISDN PPP dump that
+   * Andreas Klemm sent to wireshark-dev has a packet type of DLT_NULL,
+   * and the family bits look like PPP's protocol field.  (Was this an
+   * older, or different, ISDN driver?)  Looking at what appears to be
+   * that capture file, it appears that it's using PPP in HDLC framing,
+   * RFC 1549, wherein the first two octets of the frame are 0xFF
+   * (address) and 0x03 (control), so the header bytes are, in order:
+   *
+   *    0xFF
+   *    0x03
+   *    high-order byte of a PPP protocol field
+   *    low-order byte of a PPP protocol field
+   *
+   * If we treat that as a 32-bit host-byte-order value, it looks like
+   *
+   *    PPPP03FF
+   *
+   * where PPPP is a byte-swapped PPP protocol type if we read it on
+   * a little-endian machine and
+   *
+   *    FF03PPPP
+   *
+   * where PPPP is a PPP protocol type if we read it on a big-endian
+   * machine.  0x0000 does not appear to be a valid PPP protocol type
+   * value, so at least one of those hex digits is guaranteed not to
+   * be 0.
+   *
+   * Old versions of libpcap for Linux used DLT_NULL for loopback devices,
+   * but not any other devices.  (Current versions use DLT_EN10MB for it.)
+   * The Linux loopback driver puts an *Ethernet* header at the beginning
+   * of loopback packets, with fake source and destination addresses and
+   * the appropriate Ethernet type value; however, those older versions of
+   * libpcap for Linux compensated for this by skipping the source and
+   * destination MAC addresses, replacing them with 2 bytes of 0.
+   * This means that if we're reading the capture on a little-endian
+   * machine, the header, treated as a 32-bit integer, looks like
+   *
+   *    EEEE0000
+   *
+   * where EEEE is a byte-swapped Ethernet type, and if we're reading it
+   * on a big-endian machine, it looks like
+   *
+   *    0000EEEE
+   *
+   * where EEEE is an Ethernet type.
+   *
+   * If the first 2 bytes of the header are FF 03:
+   *
+   *    it can't be a big-endian BSD DLT_NULL header, or a DLT_LOOP
+   *    header, as AF_ values are small so the first 2 bytes of the
+   *    header would be 0;
+   *
+   *    it can't be a little-endian BSD DLT_NULL header, as the
+   *    resulting AF_ value would be >= 0x03FF, which is too big
+   *    for an AF_ value;
+   *
+   *    it can't be an IRIX or UNICOS/mp DLT_NULL header, as the
+   *    resulting AF_ value with be 0x03FF.
+   *
+   * So the first thing we do is check the first two bytes of the
+   * header; if it's FF 03, we treat the packet as a PPP frame.
+   *
+   * Otherwise, if the upper 16 bits are non-zero, either:
+   *
+   *    it's a BSD DLT_NULL header whose AF_ value is not in our
+   *    byte order;
+   *
+   *    it's an IRIX or UNICOS/mp DLT_NULL header being read on
+   *    a big-endian machine;
+   *
+   *    it's a Linux DLT_NULL header being read on a little-endian
+   *    machine.
+   *
+   * In all those cases except for the IRIX or UNICOS/mp DLT_NULL header,
+   * we should byte-swap it (if it's a Linux DLT_NULL header, that'll
+   * put the Ethernet type in the right byte order).  In the case
+   * of the IRIX or UNICOS/mp DLT_NULL header, we should just get
+   * the upper 16 bits as an AF_ value.
+   *
+   * If it's a BSD DLT_NULL header whose AF_ value is not in our byte
+   * order, then the upper 2 hex digits would be non-zero and the next
+   * 2 hex digits down would be zero, as AF_ values fit in 8 bits, and
+   * the upper 2 hex digits are the *lower* 8 bits of the value.
+   *
+   * If it's an IRIX or UNICOS/mp DLT_NULL header, the upper 2 hex digits
+   * would be zero and the next 2 hex digits down would be non-zero, as
+   * the upper 16 bits are a big-endian AF_ value.  Furthermore, the
+   * next 2 hex digits down are likely to be < 0x60, as 0x60 is 96,
+   * and, so far, we're far from requiring AF_ values that high.
+   *
+   * If it's a Linux DLT_NULL header, the third hex digit from the top
+   * will be >= 6, as Ethernet types are >= 1536, or 0x0600, and
+   * it's byte-swapped, so the second 2 hex digits from the top are
+   * >= 0x60.
+   *
+   * So, if the upper 16 bits are non-zero:
+   *
+   *    if the upper 2 hex digits are 0 and the next 2 hex digits are
+   *    in the range 0x00-0x5F, we treat it as a big-endian IRIX or
+   *    UNICOS/mp DLT_NULL header;
+   *
+   *    otherwise, we byte-swap it and do the next stage.
+   *
+   * If the upper 16 bits are zero, either:
+   *
+   *    it's a BSD DLT_NULL header whose AF_ value is in our byte
+   *    order;
+   *
+   *    it's an IRIX or UNICOS/mp DLT_NULL header being read on
+   *    a little-endian machine;
+   *
+   *    it's a Linux DLT_NULL header being read on a big-endian
+   *    machine.
+   *
+   * In all of those cases except for the IRIX or UNICOS/mp DLT_NULL header,
+   * we should *not* byte-swap it.  In the case of the IRIX or UNICOS/mp
+   * DLT_NULL header, we should extract the AF_ value and byte-swap it.
+   *
+   * If it's a BSD DLT_NULL header whose AF_ value is in our byte order,
+   * the upper 6 hex digits would all be zero.
+   *
+   * If it's an IRIX or UNICOS/mp DLT_NULL header, the upper 4 hex
+   * digits would be zero and the next 2 hex digits would not be zero.
+   * Furthermore, the third hex digit from the bottom would be <
+   */
+  if (!BYTES_ARE_IN_FRAME(0, len, 2))
+    return FALSE;
+
+  if (pd[0] == 0xFF && pd[1] == 0x03) {
+    /*
+     * Hand it to PPP.
+     */
+    return call_capture_dissector(ppp_hdlc_cap_handle, pd, 0, len, cpinfo, pseudo_header);
+  } else {
+    /*
+     * Treat it as a normal DLT_NULL header.
+     */
+    if (!BYTES_ARE_IN_FRAME(0, len, (int)sizeof(null_header)))
+      return FALSE;
+
+    memcpy((char *)&null_header, (const char *)&pd[0], sizeof(null_header));
+
+    if ((null_header & 0xFFFF0000) != 0) {
+      /*
+       * It is possible that the AF_ type was only a 16 bit value.
+       * IRIX and UNICOS/mp loopback snoop use a 4 byte header with
+       * AF_ type in the first 2 bytes!
+       * BSD AF_ types will always have the upper 8 bits as 0.
+       */
+      if ((null_header & 0xFF000000) == 0 &&
+          (null_header & 0x00FF0000) < 0x00060000) {
+        /*
+         * Looks like a IRIX or UNICOS/mp loopback header, in the
+         * correct byte order.  Set the null header value to the
+         * AF_ type, which is in the upper 16 bits of "null_header".
+         */
+        null_header >>= 16;
+      } else {
+        /* Byte-swap it. */
+        null_header = GUINT32_SWAP_LE_BE(null_header);
+      }
+    } else {
+      /*
+       * Check for an IRIX or UNICOS/mp snoop header.
+       */
+      if ((null_header & 0x000000FF) == 0 &&
+          (null_header & 0x0000FF00) < 0x00000600) {
+        /*
+         * Looks like a IRIX or UNICOS/mp loopback header, in the
+         * wrong byte order.  Set the null header value to the AF_
+         * type; that's in the lower 16 bits of "null_header", but
+         * is byte-swapped.
+         */
+        null_header = GUINT16_SWAP_LE_BE(null_header & 0xFFFF);
+      }
+    }
+
+    /*
+     * The null header value must be greater than the IEEE 802.3 maximum
+     * frame length to be a valid Ethernet type; if it is, hand it
+     * to "capture_ethertype()", otherwise treat it as a BSD AF_type (we
+     * wire in the values of the BSD AF_ types, because the values
+     * in the file will be BSD values, and the OS on which
+     * we're building this might not have the same values or
+     * might not have them defined at all; XXX - what if different
+     * BSD derivatives have different values?).
+     */
+    if (null_header > IEEE_802_3_MAX_LEN)
+      return try_capture_dissector("ethertype", null_header, pd, 4, len, cpinfo, pseudo_header);
+    else
+      return try_capture_dissector("null.bsd", null_header, pd, 4, len, cpinfo, pseudo_header);
+  }
+
+  return FALSE;
+}
+
+static int
+dissect_null(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
+{
+  guint32       null_header;
+  proto_tree    *fh_tree;
+  proto_item    *ti;
+  tvbuff_t      *next_tvb;
+
+  /*
+   * See comment in "capture_null()" for an explanation of what we're
+   * doing.
+   */
+  if (tvb_get_ntohs(tvb, 0) == 0xFF03) {
+    /*
+     * Hand it to PPP.
+     */
+    call_dissector(ppp_hdlc_handle, tvb, pinfo, tree);
+  } else {
+
+    /* load the top pane info. This should be overwritten by
+       the next protocol in the stack */
+    col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "N/A");
+    col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A");
+    col_set_str(pinfo->cinfo, COL_PROTOCOL, "N/A");
+    col_set_str(pinfo->cinfo, COL_INFO, "Null/Loopback");
+
+    /*
+     * Treat it as a normal DLT_NULL header.  Fetch it in host
+     * byte order.
+     */
+    null_header = tvb_get_h_guint32(tvb, 0);
+
+    if ((null_header & 0xFFFF0000) != 0) {
+      /*
+       * It is possible that the AF_ type was only a 16 bit value.
+       * IRIX and UNICOS/mp loopback snoop use a 4 byte header with
+       * AF_ type in the first 2 bytes!
+       * BSD AF_ types will always have the upper 8 bits as 0.
+       */
+      if ((null_header & 0xFF000000) == 0 &&
+          (null_header & 0x00FF0000) < 0x00060000) {
+        /*
+         * Looks like a IRIX or UNICOS/mp loopback header, in the
+         * correct byte order.  Set the null header value to the
+         * AF_ type, which is in the upper 16 bits of "null_header".
+         */
+        null_header >>= 16;
+      } else {
+        /* Byte-swap it. */
+        null_header = GUINT32_SWAP_LE_BE(null_header);
+      }
+    } else {
+      /*
+       * Check for an IRIX or UNICOS/mp snoop header.
+       */
+      if ((null_header & 0x000000FF) == 0 &&
+          (null_header & 0x0000FF00) < 0x00000600) {
+        /*
+         * Looks like a IRIX or UNICOS/mp loopback header, in the
+         * wrong byte order.  Set the null header value to the AF_
+         * type; that's in the lower 16 bits of "null_header", but
+         * is byte-swapped.
+         */
+        null_header = GUINT16_SWAP_LE_BE(null_header & 0xFFFF);
+      }
+    }
+
+    /*
+     * The null header value must be greater than the IEEE 802.3 maximum
+     * frame length to be a valid Ethernet type; if it is, dissect it
+     * as one, otherwise treat it as a BSD AF_type (we wire in the values
+     * of the BSD AF_ types, because the values in the file will be BSD
+     * values, and the OS on which we're building this might not have the
+     * same values or might not have them defined at all; XXX - what if
+     * different BSD derivatives have different values?).
+     */
+    if (null_header > IEEE_802_3_MAX_LEN) {
+      if (tree) {
+        ti = proto_tree_add_item(tree, proto_null, tvb, 0, 4, ENC_NA);
+        fh_tree = proto_item_add_subtree(ti, ett_null);
+        proto_tree_add_uint(fh_tree, hf_null_etype, tvb, 0, 4,
+          (guint16) null_header);
+      }
+
+      next_tvb = tvb_new_subset_remaining(tvb, 4);
+      if (!dissector_try_uint(ethertype_dissector_table,
+            (guint16) null_header, next_tvb, pinfo, tree))
+        call_data_dissector(next_tvb, pinfo, tree);
+    } else {
+      /* populate a tree in the second pane with the status of the link
+         layer (ie none) */
+      if (tree) {
+        ti = proto_tree_add_item(tree, proto_null, tvb, 0, 4, ENC_NA);
+        fh_tree = proto_item_add_subtree(ti, ett_null);
+        proto_tree_add_uint(fh_tree, hf_null_family, tvb, 0, 4, null_header);
+      }
+
+      next_tvb = tvb_new_subset_remaining(tvb, 4);
+      if (!dissector_try_uint(null_dissector_table, null_header,
+            next_tvb, pinfo, tree)) {
+        /* No sub-dissector found.  Label rest of packet as "Data" */
+        call_data_dissector(next_tvb, pinfo, tree);
+      }
+    }
+  }
+  return tvb_captured_length(tvb);
+}
+
+/*
+ * OpenBSD DLT_LOOP; like DLT_NULL, but with the first 4 byte *always*
+ * being a *big-endian* type.
+ */
+static int
+dissect_loop(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
+{
+  guint32       loop_family;
+  proto_tree    *fh_tree;
+  proto_item    *ti;
+  tvbuff_t      *next_tvb;
+
+  /* load the top pane info. This should be overwritten by
+     the next protocol in the stack */
+  col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "N/A");
+  col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A");
+  col_set_str(pinfo->cinfo, COL_PROTOCOL, "N/A");
+  col_set_str(pinfo->cinfo, COL_INFO, "Null/Loopback");
+
+  /* populate a tree in the second pane with the status of the link
+     layer (ie none) */
+  loop_family = tvb_get_ntohl(tvb, 0);
+  if (tree) {
+    ti = proto_tree_add_item(tree, proto_null, tvb, 0, 4, ENC_NA);
+    fh_tree = proto_item_add_subtree(ti, ett_null);
+    proto_tree_add_uint(fh_tree, hf_null_family, tvb, 0, 4, loop_family);
+  }
+
+  next_tvb = tvb_new_subset_remaining(tvb, 4);
+  if (!dissector_try_uint(null_dissector_table, loop_family,
+        next_tvb, pinfo, tree)) {
+    /* No sub-dissector found.  Label rest of packet as "Data" */
+    call_data_dissector(next_tvb, pinfo, tree);
+  }
+  return tvb_captured_length(tvb);
+}
+
+void
+proto_register_null(void)
+{
+  static hf_register_info hf[] = {
+
+    /* registered here but handled in ethertype.c */
+    { &hf_null_etype,
+      { "Type",         "null.type", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0,
+        NULL, HFILL }},
+
+    { &hf_null_family,
+      { "Family",       "null.family", FT_UINT32, BASE_DEC, VALS(family_vals), 0x0,
+        NULL, HFILL }}
+  };
+  static gint *ett[] = {
+    &ett_null,
+  };
+
+  proto_null = proto_register_protocol("Null/Loopback", "Null", "null");
+  proto_register_field_array(proto_null, hf, array_length(hf));
+  proto_register_subtree_array(ett, array_length(ett));
+
+  /* subdissector code */
+  null_dissector_table = register_dissector_table("null.type",
+                                                  "Null type", proto_null, FT_UINT32, BASE_DEC);
+
+  register_capture_dissector_table("null.bsd", "Null/Loopback BSD AF");
+
+  null_handle = register_dissector("null", dissect_null, proto_null);
+  loop_handle = register_dissector("null.loop", dissect_loop, proto_null);
+  null_cap_handle = register_capture_dissector("null", capture_null, proto_null);
+}
+
+void
+proto_reg_handoff_null(void)
+{
+  /*
+   * Get a handle for the PPP-in-HDLC-like-framing dissector and
+   * the "I don't know what this is" dissector.
+   */
+  ppp_hdlc_handle = find_dissector_add_dependency("ppp_hdlc", proto_null);
+
+  ethertype_dissector_table = find_dissector_table("ethertype");
+
+  dissector_add_uint("wtap_encap", WTAP_ENCAP_NULL, null_handle);
+
+  dissector_add_uint("wtap_encap", WTAP_ENCAP_LOOP, loop_handle);
+
+  capture_dissector_add_uint("wtap_encap", WTAP_ENCAP_NULL, null_cap_handle);
+  capture_dissector_add_uint("wtap_encap", WTAP_ENCAP_LOOP, null_cap_handle);
+
+  ppp_hdlc_cap_handle = find_capture_dissector("ppp_hdlc");
+}
+
+/*
+ * Editor modelines
+ *
+ * Local Variables:
+ * c-basic-offset: 2
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * ex: set shiftwidth=2 tabstop=8 expandtab:
+ * :indentSize=2:tabSize=8:noTabs=true:
+ */