我正在使用 Parse::RecDescent 来解析 Cisco IOS ACL 中的行。ACL用在大型网络的边缘路由器上，所以它包含了政府规定的近8k条线路。我正在遍历每一行并将值放入哈希中。虽然它是 8k 行，但我仍然花费超过 14 秒来解析这些行？这听起来合理吗？对我来说似乎很慢。使用散列与其他数据结构是否有一些开销？
样本输入：（大约 8k 个或类似的）
deny ip 2.3.4.5 0.0.0.7 any log-input
deny ip 5.6.7.8 0.0.0.255 any log-input
deny ip host 9.10.11.12 any log-input
deny ip 13.14.15.16 0.0.31.255 any log-input
permit tcp host 17.18.19.20 host 21.22.23.24 eq bgp
permit icmp 25.26.0.0 0.0.255.255 27.28.0.0 0.0.255.255
这是我的整个解析器：
package AccessList::Parser;
use strict;
use warnings;
use Carp;
use Scalar::Util 'blessed';
use Parse::RecDescent;
our $VERSION = '0.05';
sub new {
my ($class) = @_;
my $self = { PARSER => undef, };
bless $self, $class;
$self->_init();
return $self;
}
sub _init {
my ($self) = @_;
$self->{PARSER} = Parse::RecDescent->new( $self->_grammar() );
}
sub parse {
my ( $self, $string ) = @_;
defined ($string) or confess "blank line received";
my $tree = $self->{PARSER}->startrule($string);
defined($tree) or confess "unrecognized line\n";
return visit($tree);
}
#
# Finished tests
#
sub visit {
my ($node) = @_;
my $Rule_To_Key_Map = {
"acl_action" => 1,
"acl_protocol" => 1,
"acl_src_ip" => 1,
"acl_src_port" => 1,
"acl_dst_ip" => 1,
"acl_dst_port" => 1,
"acl_remark" => 1
};
my $parent_key;
my $result;
# set s of explored vertices
my %seen;
#stack is all neighbors of s
my @stack;
push @stack, [ $node, $parent_key ];
my $key;
while (@stack) {
my $rec = pop @stack;
$node = $rec->[0];
$parent_key = $rec->[1]; #undef for root
next if ( $seen{$node}++ );
my $rule_id = ref($node);
if ( exists( $Rule_To_Key_Map->{$rule_id} ) ) {
$parent_key = $rule_id;
}
foreach my $key ( keys %$node ) {
next if ( $key eq "EOL" );
my $next = $node->{$key};
if ( blessed($next) ) {
if ( exists( $next->{__VALUE__} ) ) {
#print ref($node), " ", ref($next), " ", $next->{__VALUE__},"\n";
my $rule = ref($node);
my $token = $next->{__VALUE__};
$result->{$parent_key} = $token;
#print $rule, " ", $result->{$rule}, "\n";
}
push @stack, [ $next, $parent_key ];
#push @stack, $next;
}
}
}
return $result;
}
sub _grammar {
my ($self) = @_;
my $grammar = q{
<autotree>
startrule :
access_list EOL
| acl_remark EOL
| <error>
#
# access-lists
#
access_list : acl_action
acl_remark :
"remark" REMARKS
acl_action :
ACTIONS acl_protocol
#
# protocol options
#
acl_protocol :
PROTOCOL acl_src_ip
#
# access-list source IP addresses
#
acl_src_ip :
address acl_dst_ip
| address acl_src_port
#
# access-list source ports
#
acl_src_port :
port acl_dst_ip
#
# access-list destination IP address
#
acl_dst_ip :
address acl_dst_port
| address acl_options
| address CONNECTION_TYPE
| address LAYER3_OPTIONS
| IPRANGE
#
# access-list destination ports
#
acl_dst_port :
port acl_options
| acl_icmp_type acl_options
#
# icmp_types
#
acl_icmp_type :
ICMP_TYPE
#
# access-list options
#
acl_options :
acl_logging LAYER3_OPTIONS
| acl_logging
| EOL
| <error>
acl_logging :
"log-input"
| "log"
#
# IP address types
#
# "object" should be fine here because "object" can not
# be used to specify ports
address :
"host" IPADDRESS
| "host" NAME
| IPNETWORK
| WILDCARD_NETWORK
| ANY
#
# port types
#
port :
port_eq
| port_range
| port_gt
| port_lt
| port_neq
port_eq :
"eq" PORT_ID
port_range :
"range" PORT_RANGE
port_gt :
"gt" PORT_GT
port_lt :
"lt" PORT_LT
port_neq :
"neq" <error: neq is unsupported>
#
# Token Definitions
#
STRING :
/\S+/
DIGIT :
/\d+/
NAME :
/((^|\s[a-zA-Z])(\.|[0-9a-zA-Z_-]+)+)/
RULE_REF :
/\S+/
ANY:
"any"
IPADDRESS :
/((\d{1,3})((\.)(\d{1,3})){3})/
MASK :
/(((255\.){3}(255|254|252|248|240|224|192|128|0+))|((255\.){2}(255|254|252|248|240|224|192|128|0+)\.0)|((255\.)(255|254|252|248|240|224|192|128|0+)(\.0+){2})|((255|254|252|248|240|224|192|128|0+)(\.0+){3}))/
INVERSE_MASK :
/(0+|1|3|7|15|31|63|127|255)((\.)(255|127|63|31|15|7|3|1|0)){3}/
WILDCARD_NETWORK :
/((\d{1,3})((\.)(\d{1,3})){3}) (0+|1|3|7|15|31|63|127|255)((\.)(255|127|63|31|15|7|3|1|0)){3}/
IPNETWORK :
/((\d{1,3})((\.)(\d{1,3})){3}) (((255\.){3}(255|254|252|248|240|224|192|128|0+))|((255\.){2}(255|254|252|248|240|224|192|128|0+)\.0)|((255\.)(255|254|252|248|240|224|192|128|0+)(\.0+){2})|((255|254|252|248|240|224|192|128|0+)(\.0+){3}))/
IPRANGE :
/((\d{1,3})((\.)(\d{1,3})){3}) ((\d{1,3})((\.)(\d{1,3})){3})/
PROTOCOL :
/\d+/ | "ahp" | "eigrp" | "esp" | "gre" | "icmp" | "icmp6" | "igmp"
| "igrp" | "ip" | "ipinip" | "ipsec" | "nos" | "ospf" | "pcp"
| "pim" | "pptp" | "snp" | "tcp" | "udp" | "41"
GROUP_PROTOCOL :
"tcp-udp" | "tcp" | "udp"
ICMP_TYPE :
/\d+/ | "alternate-address" | "conversion-error" | "echo-reply" | "echo"
| "information-reply" | "information-request" | "mask-reply" | "mask-request"
| "mobile-redirect" | "parameter-problem" | "redirect" | "router-advertisement"
| "router-solicitation" | "source-quench" | "time-exceeded" | "timestamp-reply"
| "timestamp-request" | "traceroute" | "unreachable"
CONNECTION_TYPE:
"established"
LAYER3_OPTIONS:
"fragments" | "packet-too-big"
PORT_ID :
/\S+/
PORT_GT :
/\S+/
{
bless {__VALUE__=>"$item[1] 65535"}, $item[0]
}
PORT_LT :
/\S+/
{
bless {__VALUE__=>"1 $item[1]"}, $item[0]
}
PORT_RANGE :
/\S+ \S+/
ACTIONS :
"permit"
| "deny"
REMARKS :
/.*$/
LOG_LEVEL :
/\d+/ | "emergencies" | "alerts" | "critical" | "errors"
| "warnings" | "notifications" | "informational" | "debugging"
| "disable"
EOL :
/$/
};
return $grammar;
}
1;