diff options
Diffstat (limited to 'server/mdb6.c')
| -rw-r--r-- | server/mdb6.c | 262 |
1 files changed, 242 insertions, 20 deletions
diff --git a/server/mdb6.c b/server/mdb6.c index 9d410f5..e6d0a1a 100644 --- a/server/mdb6.c +++ b/server/mdb6.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2007-2011 by Internet Systems Consortium, Inc. ("ISC") + * Copyright (C) 2007-2012 by Internet Systems Consortium, Inc. ("ISC") * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above @@ -14,9 +14,68 @@ * PERFORMANCE OF THIS SOFTWARE. */ -/* TODO: assert() */ -/* TODO: simplify functions, as pool is now in iaaddr */ +/*! + * \todo assert() + * \todo simplify functions, as pool is now in iaaddr + */ +/*! \file server/mdb6.c + * + * \page ipv6structures IPv6 Structures Overview + * + * A brief description of the IPv6 structures as reverse engineered. + * + * There are three major data strucutes involved in the database: + * ipv6_pool - this contains information about a pool of addresses or prefixes + * that the server is using. This includes a hash table that + * tracks the active items and a pair of heap tables one for + * active items and one for non-active items. The heap tables + * are used to determine the next items to be modified due to + * timing events (expire mostly). + * ia_xx - this contains information about a single IA from a request + * normally it will contain one pointer to a lease for the client + * but it may contain more in some circumstances. There are 3 + * hash tables to aid in accessing these one each for NA, TA and PD + * iasubopt - the v6 lease structure. These are creaeted dynamically when + * a client asks for something and will eventually be destroyed + * if the client doesn't re-ask for that item. A lease has space + * for backpointers to the IA and to the pool to which it belongs. + * The pool backpointer is always filled, the IA pointer may not be + * + * In normal use we then have something like this: + * + * ia hash tables + * ia_na_active +----------------+ + * ia_ta_active +------------+ | pool | + * ia_pd_active | iasubopt |<--| active hash | + * +-----------------+ | aka lease |<--| active heap | + * | ia_xx | | pool ptr |-->| | + * | iasubopt array |<---| iaptr |<--| inactive heap | + * | lease ptr |--->| | | | + * +-----------------+ +------------+ +----------------+ + * + * For the pool either the inactive heap will have a pointer + * or both the active heap and the active hash will have pointers. + * + * I think there are several major items to notice. The first is + * that as a lease moves around it will be added to and removed + * from the address hash table in the pool and between the active + * and inactive hash tables. The hash table and the active heap + * are used when the lease is either active or abandoned. The + * inactive heap is used for all other states. In particular a + * lease that has expired or been released will be cleaned + * (DDNS removal etc) and then moved to the inactive heap. After + * some time period (currently 1 hour) it will be freed. + * + * The second is that when a client requests specific addresses, + * either because it previously owned them or if the server supplied + * them as part of a solicit, the server will try to lookup the ia_xx + * associated with the client and find the addresses there. If it + * does find appropriate leases it moves them from the old IA to + * a new IA and eventually replaces the old IA with the new IA + * in the IA hash tables. + * + */ #include "config.h" #include <sys/types.h> @@ -808,15 +867,14 @@ create_lease6(struct ipv6_pool *pool, struct iasubopt **addr, } /* - * Avoid reserved interface IDs. - * (cf. draft-krishnan-ipv6-reserved-iids-02.txt) + * Avoid reserved interface IDs. (cf. RFC 5453) */ reserved_iid = ISC_FALSE; - if (memcmp(&tmp.s6_addr[8], &rtany, 8) == 0) { + if (memcmp(&tmp.s6_addr[8], &rtany.s6_addr[8], 8) == 0) { reserved_iid = ISC_TRUE; } if (!reserved_iid && - (memcmp(&tmp.s6_addr[8], &resany, 7) == 0) && + (memcmp(&tmp.s6_addr[8], &resany.s6_addr[8], 7) == 0) && ((tmp.s6_addr[15] & 0x80) == 0x80)) { reserved_iid = ISC_TRUE; } @@ -875,6 +933,145 @@ create_lease6(struct ipv6_pool *pool, struct iasubopt **addr, return result; } + +/*! \file server/mdb6.c + * + * \brief Cleans up leases when reading from a lease file + * + * This function is only expected to be run when reading leases in from a file. + * It checks to see if a lease already exists for the new leases's address. + * We don't add expired leases to the structures when reading a lease file + * which limits what can happen. We have two variables the owners of the leases + * being the same or different and the new lease being active or non-active: + * Owners active + * same no remove old lease and its connections + * same yes nothing to do, other code will update the structures. + * diff no nothing to do + * diff yes this combination shouldn't happen, we should only have a + * single active lease per address at a time and that lease + * should move to non-active before any other lease can + * become active for that address. + * Currently we delete the previous lease and pass an error + * to the caller who should log an error. + * + * When we remove a lease we remove it from the hash table and active heap + * (remember only active leases are in the structures at this time) for the + * pool, and from the IA's array. If, after we've removed the pointer from + * IA's array to the lease, the IA has no more pointers we remove it from + * the appropriate hash table as well. + * + * \param[in] ia_table = the hash table for the IA + * \param[in] pool = the pool to update + * \param[in] lease = the new lease we want to add + * \param[in] ia = the new ia we are building + * + * \return + * ISC_R_SUCCESS = the incoming lease and any previous lease were in + * an expected state - one of the first 3 options above. + * If necessary the old lease was removed. + * ISC_R_FAILURE = there is already an active lease for the address in + * the incoming lease. This shouldn't happen if it does + * flag an error for the caller to log. + */ + +isc_result_t +cleanup_lease6(ia_hash_t *ia_table, + struct ipv6_pool *pool, + struct iasubopt *lease, + struct ia_xx *ia) { + + struct iasubopt *test_iasubopt, *tmp_iasubopt; + struct ia_xx *old_ia; + isc_result_t status = ISC_R_SUCCESS; + + test_iasubopt = NULL; + old_ia = NULL; + + /* + * Look up the address - if we don't find a lease + * we don't need to do anything. + */ + if (iasubopt_hash_lookup(&test_iasubopt, pool->leases, + &lease->addr, sizeof(lease->addr), + MDL) == 0) { + return (ISC_R_SUCCESS); + } + + if (test_iasubopt->ia == NULL) { + /* no old ia, no work to do */ + iasubopt_dereference(&test_iasubopt, MDL); + return (status); + } + + ia_reference(&old_ia, test_iasubopt->ia, MDL); + + if ((old_ia->iaid_duid.len == ia->iaid_duid.len) && + (memcmp((unsigned char *)ia->iaid_duid.data, + (unsigned char *)old_ia->iaid_duid.data, + ia->iaid_duid.len) == 0)) { + /* same IA */ + if ((lease->state == FTS_ACTIVE) || + (lease->state == FTS_ABANDONED)) { + /* still active, no need to delete */ + goto cleanup; + } + } else { + /* different IA */ + if ((lease->state != FTS_ACTIVE) && + (lease->state != FTS_ABANDONED)) { + /* new lease isn't active, no work */ + goto cleanup; + } + + /* + * We appear to have two active leases, this shouldn't happen. + * Before a second lease can be set to active the first lease + * should be set to inactive (released, expired etc). For now + * delete the previous lease and indicate a failure to the + * caller so it can generate a warning. + * In the future we may try and determine which is the better + * lease to keep. + */ + + status = ISC_R_FAILURE; + } + + /* + * Remove the old lease from the active heap and from the hash table + * then remove the lease from the IA and clean up the IA if necessary. + */ + isc_heap_delete(pool->active_timeouts, test_iasubopt->heap_index); + pool->num_active--; + + iasubopt_hash_delete(pool->leases, &test_iasubopt->addr, + sizeof(test_iasubopt->addr), MDL); + ia_remove_iasubopt(old_ia, test_iasubopt, MDL); + if (old_ia->num_iasubopt <= 0) { + ia_hash_delete(ia_table, + (unsigned char *)old_ia->iaid_duid.data, + old_ia->iaid_duid.len, MDL); + } + + /* + * We derefenrece the subopt here as we've just removed it from + * the hash table in the pool. We need to make a copy as we + * need to derefernece it again later. + */ + tmp_iasubopt = test_iasubopt; + iasubopt_dereference(&tmp_iasubopt, MDL); + + cleanup: + ia_dereference(&old_ia, MDL); + + /* + * Clean up the reference, this is in addition to the deference + * above after removing the entry from the hash table + */ + iasubopt_dereference(&test_iasubopt, MDL); + + return (status); +} + /* * Put a lease in the pool directly. This is intended to be used when * loading leases from the file. @@ -985,6 +1182,38 @@ lease6_exists(const struct ipv6_pool *pool, const struct in6_addr *addr) { } } +/*! + * + * \brief Check if address is available to a lease + * + * Determine if the address in the lease is available to that + * lease. Either the address isn't in use or it is in use + * but by that lease. + * + * \param[in] lease = lease to check + * + * \return + * ISC_TRUE = The lease is allowed to use that address + * ISC_FALSE = The lease isn't allowed to use that address + */ +isc_boolean_t +lease6_usable(struct iasubopt *lease) { + struct iasubopt *test_iaaddr; + isc_boolean_t status = ISC_TRUE; + + test_iaaddr = NULL; + if (iasubopt_hash_lookup(&test_iaaddr, lease->ipv6_pool->leases, + (void *)&lease->addr, + sizeof(lease->addr), MDL)) { + if (test_iaaddr != lease) { + status = ISC_FALSE; + } + iasubopt_dereference(&test_iaaddr, MDL); + } + + return (status); +} + /* * Put the lease on our active pool. */ @@ -1058,7 +1287,7 @@ move_lease_to_inactive(struct ipv6_pool *pool, struct iasubopt *lease, #if defined (NSUPDATE) /* Process events upon expiration. */ if (pool->pool_type != D6O_IA_PD) { - ddns_removals(NULL, lease, NULL); + (void) ddns_removals(NULL, lease, NULL, ISC_FALSE); } #endif @@ -1466,6 +1695,11 @@ lease_timeout_support(void *vpool) { * Note that if there are no leases in the pool, * expire_lease6() will return ISC_R_SUCCESS with * a NULL lease. + * + * expire_lease6() will call move_lease_to_inactive() which + * calls ddns_removals() do we want that on the standard + * expiration timer or a special 'depref' timer? Original + * query from DH, moved here by SAR. */ lease = NULL; if (expire_lease6(&lease, pool, cur_time) != ISC_R_SUCCESS) { @@ -1475,18 +1709,6 @@ lease_timeout_support(void *vpool) { break; } - /* Look to see if there were ddns updates, and if - * so, drop them. - * - * DH: Do we want to do this on a special 'depref' - * timer rather than expiration timer? - */ -#if defined (NSUPDATE) - if (pool->pool_type != D6O_IA_PD) { - ddns_removals(NULL, lease, NULL); - } -#endif - write_ia(lease->ia); iasubopt_dereference(&lease, MDL); |