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https://github.com/servalproject/serval-dna.git
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120 lines
3.3 KiB
C
120 lines
3.3 KiB
C
/*
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MDP packet filtering
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Copyright (C) 2013-2014 Serval Project Inc.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include "serval.h"
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#include "overlay_address.h"
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#include "overlay_packet.h"
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#include "constants.h"
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#include "conf.h"
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#define RULE_ALLOW 0
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#define RULE_DROP (1<<0)
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#define RULE_SOURCE (1<<1)
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#define RULE_DESTINATION (1<<2)
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#define RULE_SRC_PORT (1<<3)
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#define RULE_DST_PORT (1<<4)
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struct packet_rule{
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struct subscriber *source;
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struct subscriber *destination;
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mdp_port_t src_start;
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mdp_port_t src_end;
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mdp_port_t dst_start;
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mdp_port_t dst_end;
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uint8_t flags;
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struct packet_rule *next;
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};
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struct packet_rule *global_rules = NULL;
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static int match_rule(struct internal_mdp_header *header, struct packet_rule *rule)
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{
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if ((rule->flags & RULE_SOURCE) && header->source != rule->source)
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return 0;
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if ((rule->flags & RULE_DESTINATION) && header->destination != rule->destination)
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return 0;
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if ((rule->flags & RULE_SRC_PORT) &&
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(header->source_port < rule->src_start||header->source_port > rule->src_end))
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return 0;
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if ((rule->flags & RULE_DST_PORT) &&
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(header->destination_port < rule->dst_start||header->destination_port > rule->dst_end))
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return 0;
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if (config.debug.mdprequests)
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DEBUGF("Packet matches %s rule, flags:%s%s%s%s",
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rule->flags & RULE_DROP ? "DROP" : "ALLOW",
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rule->flags & RULE_SOURCE ? " SOURCE" : "",
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rule->flags & RULE_DESTINATION ? " DESTINATION" : "",
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rule->flags & RULE_SRC_PORT? " SOURCE_PORT" : "",
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rule->flags & RULE_DST_PORT ? " DESTINATION_PORT" : "");
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return 1;
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}
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int allow_incoming_packet(struct internal_mdp_header *header)
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{
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struct packet_rule *rule = header->source->source_rules;
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while(rule){
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if (match_rule(header, rule))
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return rule->flags & RULE_DROP;
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rule = rule->next;
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}
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rule = global_rules;
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while(rule){
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if (match_rule(header, rule))
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return rule->flags & RULE_DROP;
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rule = rule->next;
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}
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return RULE_ALLOW;
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}
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static void free_rule_list(struct packet_rule *rule)
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{
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while(rule){
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struct packet_rule *t = rule;
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rule = rule->next;
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free(t);
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}
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}
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static int drop_rule(struct subscriber *subscriber, void *UNUSED(context))
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{
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free_rule_list(subscriber->source_rules);
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subscriber->source_rules=NULL;
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return 0;
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}
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void load_mdp_packet_rules(const char *UNUSED(filename))
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{
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// drop all existing rules
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free_rule_list(global_rules);
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global_rules=NULL;
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enum_subscribers(NULL, drop_rule, NULL);
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// TODO parse config [file]?
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/*
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* Rule format?
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* one line per rule, name value pairs for parameters?
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* eg;
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*
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* DROP,source=FF...,destination_port=00[-99]
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* DROP,destination=broadcast
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* ALLOW
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*
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* */
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}
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