1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
|
/* Copyright (C) 2015-2016 Internet Systems Consortium, Inc. ("ISC")
This Source Code Form is subject to the terms of the Mozilla Public
License, v. 2.0. If a copy of the MPL was not distributed with this
file, You can obtain one at http://mozilla.org/MPL/2.0/. */
%skeleton "lalr1.cc" /* -*- C++ -*- */
%require "3.0.0"
%defines
%define parser_class_name {EvalParser}
%define api.token.constructor
%define api.value.type variant
%define api.namespace {isc::eval}
%define parse.assert
%code requires
{
#include <string>
#include <eval/token.h>
#include <eval/eval_context_decl.h>
#include <dhcp/option.h>
#include <boost/lexical_cast.hpp>
using namespace isc::dhcp;
using namespace isc::eval;
}
// The parsing context.
%param { EvalContext& ctx }
%locations
%define parse.trace
%define parse.error verbose
%code
{
# include "eval_context.h"
}
%define api.token.prefix {TOKEN_}
// Tokens in an order which makes sense and related to the intented use.
%token
END 0 "end of file"
LPAREN "("
RPAREN ")"
NOT "not"
AND "and"
OR "or"
EQUAL "=="
OPTION "option"
RELAY4 "relay4"
RELAY6 "relay6"
PEERADDR "peeraddr"
LINKADDR "linkaddr"
LBRACKET "["
RBRACKET "]"
DOT "."
TEXT "text"
HEX "hex"
EXISTS "exists"
SUBSTRING "substring"
ALL "all"
COMA ","
CONCAT "concat"
;
%token <std::string> STRING "constant string"
%token <std::string> INTEGER "integer"
%token <std::string> HEXSTRING "constant hexstring"
%token <std::string> OPTION_NAME "option name"
%token <std::string> IP_ADDRESS "ip address"
%type <uint16_t> option_code
%type <TokenOption::RepresentationType> option_repr_type
%type <TokenRelay6Field::FieldType> relay6_field
%type <uint8_t> nest_level
%left OR
%left AND
%precedence NOT
%printer { yyoutput << $$; } <*>;
%%
// The whole grammar starts with an expression.
%start expression;
// Expression can either be a single token or a (something == something) expression
expression : bool_expr
;
bool_expr : "(" bool_expr ")"
| NOT bool_expr
{
TokenPtr neg(new TokenNot());
ctx.expression.push_back(neg);
}
| bool_expr AND bool_expr
{
TokenPtr neg(new TokenAnd());
ctx.expression.push_back(neg);
}
| bool_expr OR bool_expr
{
TokenPtr neg(new TokenOr());
ctx.expression.push_back(neg);
}
| string_expr EQUAL string_expr
{
TokenPtr eq(new TokenEqual());
ctx.expression.push_back(eq);
}
| OPTION "[" option_code "]" "." EXISTS
{
TokenPtr opt(new TokenOption($3, TokenOption::EXISTS));
ctx.expression.push_back(opt);
}
| RELAY4 "[" option_code "]" "." EXISTS
{
switch (ctx.getUniverse()) {
case Option::V4:
{
TokenPtr opt(new TokenRelay4Option($3, TokenOption::EXISTS));
ctx.expression.push_back(opt);
break;
}
case Option::V6:
// We will have relay6[123] for the DHCPv6.
// In a very distant future we'll possibly be able
// to mix both if we have DHCPv4-over-DHCPv6, so it
// has some sense to make it explicit whether we
// talk about DHCPv4 relay or DHCPv6 relay. However,
// for the time being relay4 can be used in DHCPv4
// only.
error(@1, "relay4 can only be used in DHCPv4.");
}
}
| RELAY6 "[" nest_level "]" "." OPTION "[" option_code "]" "." EXISTS
{
switch (ctx.getUniverse()) {
case Option::V6:
{
TokenPtr opt(new TokenRelay6Option($3, $8, TokenOption::EXISTS));
ctx.expression.push_back(opt);
break;
}
case Option::V4:
// For now we only use relay6 in DHCPv6.
error(@1, "relay6 can only be used in DHCPv6.");
}
}
;
string_expr : STRING
{
TokenPtr str(new TokenString($1));
ctx.expression.push_back(str);
}
| HEXSTRING
{
TokenPtr hex(new TokenHexString($1));
ctx.expression.push_back(hex);
}
| IP_ADDRESS
{
TokenPtr ip(new TokenIpAddress($1));
ctx.expression.push_back(ip);
}
| OPTION "[" option_code "]" "." option_repr_type
{
TokenPtr opt(new TokenOption($3, $6));
ctx.expression.push_back(opt);
}
| RELAY4 "[" option_code "]" "." option_repr_type
{
switch (ctx.getUniverse()) {
case Option::V4:
{
TokenPtr opt(new TokenRelay4Option($3, $6));
ctx.expression.push_back(opt);
break;
}
case Option::V6:
// We will have relay6[123] for the DHCPv6.
// In a very distant future we'll possibly be able
// to mix both if we have DHCPv4-over-DHCPv6, so it
// has some sense to make it explicit whether we
// talk about DHCPv4 relay or DHCPv6 relay. However,
// for the time being relay4 can be used in DHCPv4
// only.
error(@1, "relay4 can only be used in DHCPv4.");
}
}
| RELAY6 "[" nest_level "]" "." OPTION "[" option_code "]" "." option_repr_type
{
switch (ctx.getUniverse()) {
case Option::V6:
{
TokenPtr opt(new TokenRelay6Option($3, $8, $11));
ctx.expression.push_back(opt);
break;
}
case Option::V4:
// For now we only use relay6 in DHCPv6.
error(@1, "relay6 can only be used in DHCPv6.");
}
}
| RELAY6 "[" nest_level "]" "." relay6_field
{
switch (ctx.getUniverse()) {
case Option::V6:
{
TokenPtr relay6field(new TokenRelay6Field($3, $6));
ctx.expression.push_back(relay6field);
break;
}
case Option::V4:
// For now we only use relay6 in DHCPv6.
error(@1, "relay6 can only be used in DHCPv6.");
}
}
| SUBSTRING "(" string_expr "," start_expr "," length_expr ")"
{
TokenPtr sub(new TokenSubstring());
ctx.expression.push_back(sub);
}
| CONCAT "(" string_expr "," string_expr ")"
{
TokenPtr conc(new TokenConcat());
ctx.expression.push_back(conc);
}
;
option_code : INTEGER
{
$$ = ctx.convertOptionCode($1, @1);
}
| OPTION_NAME
{
$$ = ctx.convertOptionName($1, @1);
}
;
option_repr_type : TEXT
{
$$ = TokenOption::TEXTUAL;
}
| HEX
{
$$ = TokenOption::HEXADECIMAL;
}
;
start_expr : INTEGER
{
TokenPtr str(new TokenString($1));
ctx.expression.push_back(str);
}
;
length_expr : INTEGER
{
TokenPtr str(new TokenString($1));
ctx.expression.push_back(str);
}
| ALL
{
TokenPtr str(new TokenString("all"));
ctx.expression.push_back(str);
}
;
relay6_field : PEERADDR { $$ = TokenRelay6Field::PEERADDR; }
| LINKADDR { $$ = TokenRelay6Field::LINKADDR; }
;
nest_level : INTEGER
{
$$ = ctx.convertNestLevelNumber($1, @1);
}
// Eventually we may add strings to handle different
// ways of choosing from which relay we want to extract
// an option or field.
;
%%
void
isc::eval::EvalParser::error(const location_type& loc,
const std::string& what)
{
ctx.error(loc, what);
}
|
