dfilter: Add "bitand" as an alternative operator keyword

It's more compact than "bitwise_and" and inspired by C.

doc/release-notes.adoc

@@ -49,6 +49,8 @@ The following features are new (or have been significantly updated) since versio
      the multiplier/divisor must be an integer or float and appear on the right-hand
      side of the operator.
 
+  ** The keyword "bitand" can be used as an alternative syntax for the bitwise-and operator.
+
 //=== Removed Features and Support
 
 // === Removed Dissectors

doc/wireshark-filter.adoc

@@ -488,7 +488,7 @@ can be convenient:
 It is also possible to define tests with bitwise operations. Currently the
 following bitwise operator is supported:
 
-    bitwise_and, &	Bitwise AND
+    bitand, bitwise_and, &	Bitwise AND
 
 The bitwise AND operation allows masking bits and testing to see if one or
 more bits are set. Bitwise AND operates on integer protocol fields and slices.

docbook/wsug_src/wsug_work.adoc

@@ -830,16 +830,16 @@ You can perform the arithmetic operations on numeric fields shown in <<Arithmeti
 [#ArithmeticOps]
 
 .Display Filter Arithmetic Operations
-[options="header",cols="1,1,4"]
+[options="header",cols="1,1,1,4"]
 |===
-|Name            |Syntax    | Description
-|Unary minus     |-A        | Negation of A
-|Addition        |A + B     | Add B to A
-|Subtraction     |A - B     | Subtract B from A
-|Multiplication  |A * B     | Multiply A times B
-|Division        |A / B     | Divide A by B
-|Modulo          |A % B     | Remainder of A divided by B
-|Bitwise AND     |A & B     | Bitwise AND of A and B
+|Name            |Syntax    | Alternative | Description
+|Unary minus     |-A        |             | Negation of A
+|Addition        |A + B     |             | Add B to A
+|Subtraction     |A - B     |             | Subtract B from A
+|Multiplication  |A * B     |             | Multiply A times B
+|Division        |A / B     |             | Divide A by B
+|Modulo          |A % B     |             | Remainder of A divided by B
+|Bitwise AND     |A & B     | A bitand B  | Bitwise AND of A and B
 |===
 
 Arithmetic expressions can be grouped using curly braces.

epan/dfilter/scanner.l

@@ -206,6 +206,7 @@ HexExponent		([pP][+-]?[[:digit:]]+)
 "/"		return math(TOKEN_RSLASH);
 "%"		return math(TOKEN_PERCENT);
 "&"		return math(TOKEN_BITWISE_AND);
+"bitand"	return math(TOKEN_BITWISE_AND);
 "bitwise_and"	return math(TOKEN_BITWISE_AND);
 
 "#"				{

epan/proto.c

@@ -484,6 +484,7 @@ static const char *reserved_filter_names[] = {
 	"ge",
 	"lt",
 	"le",
+	"bitand",
 	"bitwise_and",
 	"contains",
 	"matches",

test/suite_dfilter/group_syntax.py

@@ -218,6 +218,10 @@ class TestDfilterBitwise:
         checkDFilterCount(dfilter, 1)
 
     def test_exists_2(self, checkDFilterCount):
+        dfilter = "tcp.flags bitand 0x8"
+        checkDFilterCount(dfilter, 1)
+
+    def test_exists_3(self, checkDFilterCount):
         dfilter = "eth[0] & 1"
         checkDFilterCount(dfilter, 0)
 
@@ -229,6 +233,14 @@ class TestDfilterBitwise:
         dfilter = "tcp.srcport != tcp.dstport & 0x0F"
         checkDFilterCount(dfilter, 1)
 
+    def test_equal_3(self, checkDFilterCount):
+        dfilter = "tcp.srcport != tcp.dstport bitand 0x0F"
+        checkDFilterCount(dfilter, 1)
+
+    def test_equal_4(self, checkDFilterCount):
+        dfilter = "tcp.srcport != tcp.dstport bitwise_and 0x0F"
+        checkDFilterCount(dfilter, 1)
+
 class TestDfilterUnaryMinus:
     trace_file = "http.pcap"