Add tvb_get and proto_tree_add for string-encoded byte arrays

This commit adds tvb_get_string_bytes and proto_tree_add_bytes_item routines for
getting GByteArrays fields from the tvb when they are encoded in ASCII hex string form.

The proto_tree_add_bytes_item routine is also usable for normal
binary encoded byte arrays, and has the advantage of retrieving
the array values even if there's no proto tree.

It also exposes the routines to Lua, both so that a Lua script can take
advantage of this, but also so I can write a testsuite to test the functions.

Change-Id: I112a038653df6482a5d0ebe7c95708f207319e20
Reviewed-on: https://code.wireshark.org/review/1158
Reviewed-by: Hadriel Kaplan <hadrielk@yahoo.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 63 insertions, 4 deletions

diff --git a/epan/wslua/wslua_tvb.c b/epan/wslua/wslua_tvb.c
index a48e48f32c..d40de58436 100644
--- a/epan/wslua/wslua_tvb.c
+++ b/epan/wslua/wslua_tvb.c
@@ -106,6 +106,27 @@ WSLUA_METAMETHOD ByteArray__concat(lua_State* L) {
     WSLUA_RETURN(1); /* The new composite `ByteArray`. */
 }
 
+WSLUA_METAMETHOD ByteArray__eq(lua_State* L) {
+    /* Compares two ByteArray values.
+
+       @since 1.11.4
+     */
+#define WSLUA_ARG_ByteArray__eq_FIRST 1 /* First array. */
+#define WSLUA_ARG_ByteArray__eq_SECOND 2 /* Second array. */
+    ByteArray ba1 = checkByteArray(L,WSLUA_ARG_ByteArray__eq_FIRST);
+    ByteArray ba2 = checkByteArray(L,WSLUA_ARG_ByteArray__eq_SECOND);
+    gboolean result = FALSE;
+
+    if (ba1->len == ba2->len) {
+        if (memcmp(ba1->data, ba2->data, ba1->len) == 0)
+            result = TRUE;
+    }
+
+    lua_pushboolean(L,result);
+
+    return 1;
+}
+
 WSLUA_METHOD ByteArray_prepend(lua_State* L) {
 	/* Prepend a `ByteArray` to this `ByteArray`. */
 #define WSLUA_ARG_ByteArray_prepend_PREPENDED 2 /* `ByteArray` to be prepended. */
@@ -325,6 +346,7 @@ WSLUA_METHODS ByteArray_methods[] = {
 WSLUA_META ByteArray_meta[] = {
     WSLUA_CLASS_MTREG(ByteArray,tostring),
     WSLUA_CLASS_MTREG(ByteArray,concat),
+    WSLUA_CLASS_MTREG(ByteArray,eq),
     {"__call",ByteArray_subset},
     { NULL, NULL }
 };
@@ -1309,9 +1331,25 @@ WSLUA_METHOD TvbRange_le_ustringz(lua_State* L) {
 }
 
 WSLUA_METHOD TvbRange_bytes(lua_State* L) {
-	/* Obtain a `ByteArray` from a `TvbRange`. */
+	/* Obtain a `ByteArray` from a `TvbRange`.
+
+       Starting in 1.11.4, this function also takes an optional `encoding` argument,
+       which can be set to `ENC_STR_HEX` to decode a hex-string from the `TvbRange`
+       into the returned `ByteArray`. The `encoding` can be bitwise-or'ed with one
+       or more separator encodings, such as `ENC_SEP_COLON`, to allow separators
+       to occur between each pair of hex characters.
+
+       The return value also now returns the number of bytes used as a second return value.
+
+       On failure or error, nil is returned for both return values.
+
+       @note The encoding type of the hex string should also be set, for example
+       `ENC_ASCII` or `ENC_UTF_8`, along with `ENC_STR_HEX`.
+     */
+#define WSLUA_OPTARG_TvbRange_bytes_ENCODING 2 /* An optional ENC_* encoding value to use */
     TvbRange tvbr = checkTvbRange(L,1);
     GByteArray* ba;
+    const guint encoding = luaL_optint(L, WSLUA_OPTARG_TvbRange_bytes_ENCODING, 0);
 
     if ( !(tvbr && tvbr->tvb)) return 0;
     if (tvbr->tvb->expired) {
@@ -1320,11 +1358,32 @@ WSLUA_METHOD TvbRange_bytes(lua_State* L) {
     }
 
     ba = g_byte_array_new();
-    g_byte_array_append(ba,(const guint8 *)tvb_memdup(wmem_packet_scope(),tvbr->tvb->ws_tvb,tvbr->offset,tvbr->len),tvbr->len);
 
-    pushByteArray(L,ba);
+    if (encoding == 0) {
+        g_byte_array_append(ba,(const guint8 *)tvb_memdup(wmem_packet_scope(),tvbr->tvb->ws_tvb,tvbr->offset,tvbr->len),tvbr->len);
+        pushByteArray(L,ba);
+        lua_pushinteger(L, tvbr->len);
+    }
+    else if ((encoding & ENC_STR_HEX) == 0) {
+        WSLUA_OPTARG_ERROR(TvbRange_nstime, ENCODING, "invalid encoding value");
+    }
+    else {
+        gint endoff = 0;
+        GByteArray* retval = tvb_get_string_bytes(tvbr->tvb->ws_tvb, tvbr->offset, tvbr->len,
+                                                  encoding, ba, &endoff);
+        if (!retval || endoff == 0) {
+            g_byte_array_free(ba, TRUE);
+            /* push nil nstime and offset */
+            lua_pushnil(L);
+            lua_pushnil(L);
+        }
+        else {
+            pushByteArray(L,ba);
+            lua_pushinteger(L, endoff);
+        }
+    }
 
-    WSLUA_RETURN(1); /* The `ByteArray` object. */
+    WSLUA_RETURN(2); /* The `ByteArray` object or nil, and number of bytes consumed or nil. */
 }
 
 WSLUA_METHOD TvbRange_bitfield(lua_State* L) {