kea/src/lib/eval/parser.yy

/* 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"
  PKT "pkt"
  IFACE "iface"
  SRC "src"
  DST "dst"
  LEN "len"
  PKT4 "pkt4"
  CHADDR "mac"
  HLEN "hlen"
  HTYPE "htype"
  CIADDR "ciaddr"
  GIADDR "giaddr"
  YIADDR "yiaddr"
  SIADDR "siaddr"
  PKT6 "pkt6"
  MSGTYPE "msgtype"
  TRANSID "transid"
  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
%type <TokenPkt::MetadataType> pkt_metadata
%type <TokenPkt4::FieldType> pkt4_field
%type <TokenPkt6::FieldType> pkt6_field

%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.");
                     }
                  }

            | PKT "." pkt_metadata
                  {
                      TokenPtr pkt_metadata(new TokenPkt($3));
                      ctx.expression.push_back(pkt_metadata);
                  }
            | PKT4 "." pkt4_field
                  {
                     switch (ctx.getUniverse()) {
                     case Option::V4:
                     {
                         TokenPtr pkt4_field(new TokenPkt4($3));
                         ctx.expression.push_back(pkt4_field);
                         break;
                     }
                     case Option::V6:
                         // For now we only use pkt4 in DHCPv4.
                         error(@1, "pkt4 can only be used in DHCPv4.");
                     }
                  }
            | PKT6 "." pkt6_field
                  {
                     switch (ctx.getUniverse()) {
                     case Option::V6:
                     {
                         TokenPtr pkt6_field(new TokenPkt6($3));
                         ctx.expression.push_back(pkt6_field);
                         break;
                     }
                     case Option::V4:
                         // For now we only use pkt6 in DHCPv6.
                         error(@1, "pkt6 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;
                      }
                 ;

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.
           ;

pkt_metadata : IFACE
                  {
                      $$ = TokenPkt::IFACE;
                  }
             | SRC
                  {
                      $$ = TokenPkt::SRC;
                  }
             | DST
                  {
                      $$ = TokenPkt::DST;
                  }
             | LEN
                  {
                      $$ = TokenPkt::LEN;
                  }
             ;

pkt4_field : CHADDR
                {
                    $$ = TokenPkt4::CHADDR;
                }
           | HLEN
                {
                    $$ = TokenPkt4::HLEN;
                }
           | HTYPE
                {
                    $$ = TokenPkt4::HTYPE;
                }
           | CIADDR
                {
                    $$ = TokenPkt4::CIADDR;
                }
           | GIADDR
                {
                    $$ = TokenPkt4::GIADDR;
                }
           | YIADDR
                {
                    $$ = TokenPkt4::YIADDR;
                }
           | SIADDR
                {
                    $$ = TokenPkt4::SIADDR;
                }
           ;

pkt6_field : MSGTYPE
                 {
                     $$ = TokenPkt6::MSGTYPE;
                 }
           | TRANSID
                 {
                     $$ = TokenPkt6::TRANSID;
                 }
           ;

relay6_field : PEERADDR
                   {
                       $$ = TokenRelay6Field::PEERADDR;
                   }
             | LINKADDR
                   {
                       $$ = TokenRelay6Field::LINKADDR;
                   }
             ;

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);
                 }
            ;

%%
void
isc::eval::EvalParser::error(const location_type& loc,
                             const std::string& what)
{
    ctx.error(loc, what);
}