isc-dhcp/server/class.c

/* class.c

   Handling for client classes. */

/*
 * Copyright (C) 2004-2022 Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1998-2003 by Internet Software Consortium
 *
 * 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/.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 *   Internet Systems Consortium, Inc.
 *   PO Box 360
 *   Newmarket, NH 03857 USA
 *   <info@isc.org>
 *   https://www.isc.org/
 *
 */

#include "dhcpd.h"

struct executable_statement *default_classification_rules;

int have_billing_classes;

/* Build the default classification rule tree. */

void classification_setup ()
{
	/* eval ... */
	default_classification_rules = (struct executable_statement *)0;
	if (!executable_statement_allocate (&default_classification_rules,
					    MDL))
		log_fatal ("Can't allocate check of default collection");
	default_classification_rules -> op = eval_statement;

	/* check-collection "default" */
	if (!expression_allocate (&default_classification_rules -> data.eval,
				  MDL))
		log_fatal ("Can't allocate default check expression");
	default_classification_rules -> data.eval -> op = expr_check;
	default_classification_rules -> data.eval -> data.check =
		&default_collection;
}

void classify_client (packet)
	struct packet *packet;
{
	execute_statements (NULL, packet, NULL, NULL, packet->options, NULL,
			    &global_scope, default_classification_rules, NULL);
}

int check_collection (packet, lease, collection)
	struct packet *packet;
	struct lease *lease;
	struct collection *collection;
{
	struct class *class, *nc;
	struct data_string data;
	int matched = 0;
	int status;
	int ignorep;
	int classfound;

	for (class = collection -> classes; class; class = class -> nic) {
#if defined (DEBUG_CLASS_MATCHING)
		log_info ("checking against class %s...", class -> name);
#endif
		memset (&data, 0, sizeof data);

		/* If there is a "match if" expression, check it.   If
		   we get a match, and there's no subclass expression,
		   it's a match.   If we get a match and there is a subclass
		   expression, then we check the submatch.   If it's not a
		   match, that's final - we don't check the submatch. */

		if (class -> expr) {
			status = (evaluate_boolean_expression_result
				  (&ignorep, packet, lease,
				   (struct client_state *)0,
				   packet -> options, (struct option_state *)0,
				   lease ? &lease -> scope : &global_scope,
				   class -> expr));
			if (status) {
				if (!class -> submatch) {
					matched = 1;
#if defined (DEBUG_CLASS_MATCHING)
					log_info ("matches class.");
#endif
					classify (packet, class);
					continue;
				}
			} else
				continue;
		}

		/* Check to see if the client matches an existing subclass.
		   If it doesn't, and this is a spawning class, spawn a new
		   subclass and put the client in it. */
		if (class -> submatch) {
			status = (evaluate_data_expression
				  (&data, packet, lease,
				   (struct client_state *)0,
				   packet -> options, (struct option_state *)0,
				   lease ? &lease -> scope : &global_scope,
				   class -> submatch, MDL));
			if (status && data.len) {
				nc = (struct class *)0;
				classfound = class_hash_lookup (&nc, class -> hash,
					(const char *)data.data, data.len, MDL);

#ifdef LDAP_CONFIGURATION
				if (!classfound && find_subclass_in_ldap (class, &nc, &data))
					classfound = 1;
#endif

				if (classfound) {
#if defined (DEBUG_CLASS_MATCHING)
					log_info ("matches subclass %s.",
					      print_hex_1 (data.len,
							   data.data, 60));
#endif
					data_string_forget (&data, MDL);
					classify (packet, nc);
					matched = 1;
					class_dereference (&nc, MDL);
					continue;
				}
				if (!class -> spawning) {
					data_string_forget (&data, MDL);
					continue;
				}
				/* XXX Write out the spawned class? */
#if defined (DEBUG_CLASS_MATCHING)
				log_info ("spawning subclass %s.",
				      print_hex_1 (data.len, data.data, 60));
#endif
				status = class_allocate (&nc, MDL);
				group_reference (&nc -> group,
						 class -> group, MDL);
				class_reference (&nc -> superclass,
						 class, MDL);
				nc -> lease_limit = class -> lease_limit;
				nc -> dirty = 1;
				if (nc -> lease_limit) {
					nc -> billed_leases =
						(dmalloc
						 (nc -> lease_limit *
						  sizeof (struct lease *),
						  MDL));
					if (!nc -> billed_leases) {
						log_error ("no memory for%s",
							   " billing");
						data_string_forget
							(&nc -> hash_string,
							 MDL);
						class_dereference (&nc, MDL);
						data_string_forget (&data,
								    MDL);
						continue;
					}
					memset (nc -> billed_leases, 0,
						(nc -> lease_limit *
						 sizeof (struct lease *)));
				}
				data_string_copy (&nc -> hash_string, &data,
						  MDL);
				if (!class -> hash)
				    class_new_hash(&class->hash,
						   SCLASS_HASH_SIZE, MDL);
				class_hash_add (class -> hash,
						(const char *)
						nc -> hash_string.data,
						nc -> hash_string.len,
						nc, MDL);
				classify (packet, nc);
				class_dereference (&nc, MDL);
			}

			data_string_forget (&data, MDL);
		}
	}
	return matched;
}

void classify (packet, class)
	struct packet *packet;
	struct class *class;
{
	if (packet -> class_count < PACKET_MAX_CLASSES)
		class_reference (&packet -> classes [packet -> class_count++],
				 class, MDL);
	else
		log_error ("too many classes match %s",
		      print_hw_addr (packet -> raw -> htype,
				     packet -> raw -> hlen,
				     packet -> raw -> chaddr));
}


isc_result_t unlink_class(struct class **class) {
	struct collection *lp;
	struct class *cp, *pp;

	for (lp = collections; lp; lp = lp -> next) {
		for (pp = 0, cp = lp -> classes; cp; pp = cp, cp = cp -> nic)
			if (cp == *class) {
				if (pp == 0) {
					lp->classes = cp->nic;
				} else {
					pp->nic = cp->nic;
				}
				cp->nic = 0;
				class_dereference(class, MDL);

				return ISC_R_SUCCESS;
			}
	}
	return ISC_R_NOTFOUND;
}


isc_result_t find_class (struct class **class, const char *name,
			 const char *file, int line)
{
	struct collection *lp;
	struct class *cp;

	for (lp = collections; lp; lp = lp -> next) {
		for (cp = lp -> classes; cp; cp = cp -> nic)
			if (cp -> name && !strcmp (name, cp -> name)) {
				return class_reference (class, cp, file, line);
			}
	}
	return ISC_R_NOTFOUND;
}

/* Removes the billing class from a lease
 *
 * Note that because classes can be created and removed dynamically, it is
 * possible that the class to which a lease was billed has since been deleted.
 * To cover the case where the lease is the last reference to a deleted class
 * we remove the lease reference from the class first, then the class from the
 * lease.  To protect ourselves from the reverse situation, where the class is
 * the last reference to the lease (unlikely), we create a guard reference to
 * the lease, then remove it at the end.
 */
void unbill_class (lease)
	struct lease *lease;
{
	int i;
	struct class* class = lease->billing_class;
	struct lease* refholder = NULL;

	/* if there's no billing to remove, nothing to do */
	if (class == NULL) {
		return;
	}

	/* Find the lease in the list of the class's billed leases */
	for (i = 0; i < class->lease_limit; i++) {
		if (class->billed_leases[i] == lease)
			break;
	}

	/* Create guard reference, so class cannot be last reference to lease */
	lease_reference(&refholder, lease, MDL);

	/* If the class doesn't have the lease, then something is broken
	 * programmatically.  We'll log it but skip the lease dereference. */
	if (i == class->lease_limit) {
		log_error ("lease %s unbilled with no billing arrangement.",
			   piaddr(lease->ip_addr));
	} else {
		/* Remove the lease from the class */
		lease_dereference(&class->billed_leases[i], MDL);
		class->leases_consumed--;
	}

	/* Remove the class from the lease */
	class_dereference(&lease->billing_class, MDL);

	/* Ditch our guard reference */
	lease_dereference(&refholder, MDL);
}

int bill_class (lease, class)
	struct lease *lease;
	struct class *class;
{
	int i;

	if (lease -> billing_class) {
		log_error ("lease billed with existing billing arrangement.");
		unbill_class (lease);
	}

	if (class -> leases_consumed == class -> lease_limit)
		return 0;

	for (i = 0; i < class -> lease_limit; i++)
		if (!class -> billed_leases [i])
			break;

	if (i == class -> lease_limit) {
		log_error ("class billing consumption disagrees with leases.");
		return 0;
	}

	lease_reference (&class -> billed_leases [i], lease, MDL);
	class_reference (&lease -> billing_class, class, MDL);
	class -> leases_consumed++;
	return 1;
}