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dns
dispatch.h
/* * Copyright (C) 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 https://mozilla.org/MPL/2.0/. * * See the COPYRIGHT file distributed with this work for additional * information regarding copyright ownership. */ #ifndef DNS_DISPATCH_H #define DNS_DISPATCH_H 1 /***** ***** Module Info *****/ /*! \file dns/dispatch.h * \brief * DNS Dispatch Management * Shared UDP and single-use TCP dispatches for queries and responses. * * MP: * *\li All locking is performed internally to each dispatch. * Restrictions apply to dns_dispatch_removeresponse(). * * Reliability: * * Resources: * * Security: * *\li Depends on the isc_socket_t and dns_message_t for prevention of * buffer overruns. * * Standards: * *\li None. */ /*** *** Imports ***/ #include <stdbool.h> #include <isc/buffer.h> #include <isc/lang.h> #include <isc/mutex.h> #include <isc/socket.h> #include <isc/types.h> #include <dns/types.h> ISC_LANG_BEGINDECLS /*% * This event is sent to a task when a response comes in. * No part of this structure should ever be modified by the caller, * other than parts of the buffer. The holy parts of the buffer are * the base and size of the buffer. All other parts of the buffer may * be used. On event delivery the used region contains the packet. * * "id" is the received message id, * * "addr" is the host that sent it to us, * * "buffer" holds state on the received data. * * The "free" routine for this event will clean up itself as well as * any buffer space allocated from common pools. */ struct dns_dispatchevent { ISC_EVENT_COMMON(dns_dispatchevent_t); /*%< standard event common */ isc_result_t result; /*%< result code */ int32_t id; /*%< message id */ isc_sockaddr_t addr; /*%< address recv'd from */ struct in6_pktinfo pktinfo; /*%< reply info for v6 */ isc_buffer_t buffer; /*%< data buffer */ uint32_t attributes; /*%< mirrored from socket.h */ }; /*% * This is a set of one or more dispatches which can be retrieved * round-robin fashion. */ struct dns_dispatchset { isc_mem_t *mctx; dns_dispatch_t **dispatches; int ndisp; int cur; isc_mutex_t lock; }; /*@{*/ /*% * Attributes for added dispatchers. * * Values with the mask 0xffff0000 are application defined. * Values with the mask 0x0000ffff are library defined. * * Insane values (like setting both TCP and UDP) are not caught. Don't * do that. * * _PRIVATE * The dispatcher cannot be shared. * * _TCP, _UDP * The dispatcher is a TCP or UDP socket. * * _IPV4, _IPV6 * The dispatcher uses an IPv4 or IPv6 socket. * * _NOLISTEN * The dispatcher should not listen on the socket. * * _MAKEQUERY * The dispatcher can be used to issue queries to other servers, and * accept replies from them. * * _RANDOMPORT * Previously used to indicate that the port of a dispatch UDP must be * chosen randomly. This behavior now always applies and the attribute * is obsoleted. * * _EXCLUSIVE * A separate socket will be used on-demand for each transaction. */ #define DNS_DISPATCHATTR_PRIVATE 0x00000001U #define DNS_DISPATCHATTR_TCP 0x00000002U #define DNS_DISPATCHATTR_UDP 0x00000004U #define DNS_DISPATCHATTR_IPV4 0x00000008U #define DNS_DISPATCHATTR_IPV6 0x00000010U #define DNS_DISPATCHATTR_NOLISTEN 0x00000020U #define DNS_DISPATCHATTR_MAKEQUERY 0x00000040U #define DNS_DISPATCHATTR_CONNECTED 0x00000080U #define DNS_DISPATCHATTR_FIXEDID 0x00000100U #define DNS_DISPATCHATTR_EXCLUSIVE 0x00000200U /*@}*/ /* */ #define DNS_DISPATCHOPT_FIXEDID 0x00000001U isc_result_t dns_dispatchmgr_create(isc_mem_t *mctx, isc_entropy_t *entropy, dns_dispatchmgr_t **mgrp); /*%< * Creates a new dispatchmgr object. * * Requires: *\li "mctx" be a valid memory context. * *\li mgrp != NULL && *mgrp == NULL * *\li "entropy" may be NULL, in which case an insecure random generator * will be used. If it is non-NULL, it must be a valid entropy * source. * * Returns: *\li ISC_R_SUCCESS -- all ok * *\li anything else -- failure */ void dns_dispatchmgr_destroy(dns_dispatchmgr_t **mgrp); /*%< * Destroys the dispatchmgr when it becomes empty. This could be * immediately. * * Requires: *\li mgrp != NULL && *mgrp is a valid dispatchmgr. */ void dns_dispatchmgr_setblackhole(dns_dispatchmgr_t *mgr, dns_acl_t *blackhole); /*%< * Sets the dispatcher's "blackhole list," a list of addresses that will * be ignored by all dispatchers created by the dispatchmgr. * * Requires: * \li mgrp is a valid dispatchmgr * \li blackhole is a valid acl */ dns_acl_t * dns_dispatchmgr_getblackhole(dns_dispatchmgr_t *mgr); /*%< * Gets a pointer to the dispatcher's current blackhole list, * without incrementing its reference count. * * Requires: *\li mgr is a valid dispatchmgr * Returns: *\li A pointer to the current blackhole list, or NULL. */ void dns_dispatchmgr_setblackportlist(dns_dispatchmgr_t *mgr, dns_portlist_t *portlist); /*%< * This function is deprecated. Use dns_dispatchmgr_setavailports() instead. * * Requires: *\li mgr is a valid dispatchmgr */ dns_portlist_t * dns_dispatchmgr_getblackportlist(dns_dispatchmgr_t *mgr); /*%< * This function is deprecated and always returns NULL. * * Requires: *\li mgr is a valid dispatchmgr */ isc_result_t dns_dispatchmgr_setavailports(dns_dispatchmgr_t *mgr, isc_portset_t *v4portset, isc_portset_t *v6portset); /*%< * Sets a list of UDP ports that can be used for outgoing UDP messages. * * Requires: *\li mgr is a valid dispatchmgr *\li v4portset is NULL or a valid port set *\li v6portset is NULL or a valid port set */ void dns_dispatchmgr_setstats(dns_dispatchmgr_t *mgr, isc_stats_t *stats); /*%< * Sets statistics counter for the dispatchmgr. This function is expected to * be called only on zone creation (when necessary). * Once installed, it cannot be removed or replaced. Also, there is no * interface to get the installed stats from the zone; the caller must keep the * stats to reference (e.g. dump) it later. * * Requires: *\li mgr is a valid dispatchmgr with no managed dispatch. *\li stats is a valid statistics supporting resolver statistics counters * (see dns/stats.h). */ isc_result_t dns_dispatch_getudp(dns_dispatchmgr_t *mgr, isc_socketmgr_t *sockmgr, isc_taskmgr_t *taskmgr, isc_sockaddr_t *localaddr, unsigned int buffersize, unsigned int maxbuffers, unsigned int maxrequests, unsigned int buckets, unsigned int increment, unsigned int attributes, unsigned int mask, dns_dispatch_t **dispp); isc_result_t dns_dispatch_getudp_dup(dns_dispatchmgr_t *mgr, isc_socketmgr_t *sockmgr, isc_taskmgr_t *taskmgr, isc_sockaddr_t *localaddr, unsigned int buffersize, unsigned int maxbuffers, unsigned int maxrequests, unsigned int buckets, unsigned int increment, unsigned int attributes, unsigned int mask, dns_dispatch_t **dispp, dns_dispatch_t *dup); /*%< * Attach to existing dns_dispatch_t if one is found with dns_dispatchmgr_find, * otherwise create a new UDP dispatch. * * Requires: *\li All pointer parameters be valid for their respective types. * *\li dispp != NULL && *disp == NULL * *\li 512 <= buffersize <= 64k * *\li maxbuffers > 0 * *\li buckets < 2097169 * *\li increment > buckets * *\li (attributes & DNS_DISPATCHATTR_TCP) == 0 * * Returns: *\li ISC_R_SUCCESS -- success. * *\li Anything else -- failure. */ isc_result_t dns_dispatch_createtcp(dns_dispatchmgr_t *mgr, isc_socket_t *sock, isc_taskmgr_t *taskmgr, unsigned int buffersize, unsigned int maxbuffers, unsigned int maxrequests, unsigned int buckets, unsigned int increment, unsigned int attributes, dns_dispatch_t **dispp); isc_result_t dns_dispatch_createtcp2(dns_dispatchmgr_t *mgr, isc_socket_t *sock, isc_taskmgr_t *taskmgr, isc_sockaddr_t *localaddr, isc_sockaddr_t *destaddr, unsigned int buffersize, unsigned int maxbuffers, unsigned int maxrequests, unsigned int buckets, unsigned int increment, unsigned int attributes, dns_dispatch_t **dispp); /*%< * Create a new dns_dispatch and attach it to the provided isc_socket_t. * * For all dispatches, "buffersize" is the maximum packet size we will * accept. * * "maxbuffers" and "maxrequests" control the number of buffers in the * overall system and the number of buffers which can be allocated to * requests. * * "buckets" is the number of buckets to use, and should be prime. * * "increment" is used in a collision avoidance function, and needs to be * a prime > buckets, and not 2. * * Requires: * *\li mgr is a valid dispatch manager. * *\li sock is a valid. * *\li task is a valid task that can be used internally to this dispatcher. * * \li 512 <= buffersize <= 64k * *\li maxbuffers > 0. * *\li maxrequests <= maxbuffers. * *\li buckets < 2097169 (the next prime after 65536 * 32) * *\li increment > buckets (and prime). * *\li attributes includes #DNS_DISPATCHATTR_TCP and does not include * #DNS_DISPATCHATTR_UDP. * * Returns: *\li ISC_R_SUCCESS -- success. * *\li Anything else -- failure. */ void dns_dispatch_attach(dns_dispatch_t *disp, dns_dispatch_t **dispp); /*%< * Attach to a dispatch handle. * * Requires: *\li disp is valid. * *\li dispp != NULL && *dispp == NULL */ void dns_dispatch_detach(dns_dispatch_t **dispp); /*%< * Detaches from the dispatch. * * Requires: *\li dispp != NULL and *dispp be a valid dispatch. */ void dns_dispatch_starttcp(dns_dispatch_t *disp); /*%< * Start processing of a TCP dispatch once the socket connects. * * Requires: *\li 'disp' is valid. */ isc_result_t dns_dispatch_gettcp(dns_dispatchmgr_t *mgr, isc_sockaddr_t *destaddr, isc_sockaddr_t *localaddr, dns_dispatch_t **dispp); isc_result_t dns_dispatch_gettcp2(dns_dispatchmgr_t *mgr, isc_sockaddr_t *destaddr, isc_sockaddr_t *localaddr, bool *connected, dns_dispatch_t **dispp); /* * Attempt to connect to a existing TCP connection (connection completed * for dns_dispatch_gettcp()). */ isc_result_t dns_dispatch_addresponse3(dns_dispatch_t *disp, unsigned int options, isc_sockaddr_t *dest, isc_task_t *task, isc_taskaction_t action, void *arg, uint16_t *idp, dns_dispentry_t **resp, isc_socketmgr_t *sockmgr); isc_result_t dns_dispatch_addresponse2(dns_dispatch_t *disp, isc_sockaddr_t *dest, isc_task_t *task, isc_taskaction_t action, void *arg, uint16_t *idp, dns_dispentry_t **resp, isc_socketmgr_t *sockmgr); isc_result_t dns_dispatch_addresponse(dns_dispatch_t *disp, isc_sockaddr_t *dest, isc_task_t *task, isc_taskaction_t action, void *arg, uint16_t *idp, dns_dispentry_t **resp); /*%< * Add a response entry for this dispatch. * * "*idp" is filled in with the assigned message ID, and *resp is filled in * to contain the magic token used to request event flow stop. * * Arranges for the given task to get a callback for response packets. When * the event is delivered, it must be returned using dns_dispatch_freeevent() * or through dns_dispatch_removeresponse() for another to be delivered. * * Requires: *\li "idp" be non-NULL. * *\li "task" "action" and "arg" be set as appropriate. * *\li "dest" be non-NULL and valid. * *\li "resp" be non-NULL and *resp be NULL * *\li "sockmgr" be NULL or a valid socket manager. If 'disp' has * the DNS_DISPATCHATTR_EXCLUSIVE attribute, this must not be NULL, * which also means dns_dispatch_addresponse() cannot be used. * * Ensures: * *\li <id, dest> is a unique tuple. That means incoming messages * are identifiable. * * Returns: * *\li ISC_R_SUCCESS -- all is well. *\li ISC_R_NOMEMORY -- memory could not be allocated. *\li ISC_R_NOMORE -- no more message ids can be allocated * for this destination. */ void dns_dispatch_removeresponse(dns_dispentry_t **resp, dns_dispatchevent_t **sockevent); /*%< * Stops the flow of responses for the provided id and destination. * If "sockevent" is non-NULL, the dispatch event and associated buffer is * also returned to the system. * * Requires: *\li "resp" != NULL and "*resp" contain a value previously allocated * by dns_dispatch_addresponse(); * *\li May only be called from within the task given as the 'task' * argument to dns_dispatch_addresponse() when allocating '*resp'. */ isc_socket_t * dns_dispatch_getentrysocket(dns_dispentry_t *resp); isc_socket_t * dns_dispatch_getsocket(dns_dispatch_t *disp); /*%< * Return the socket associated with this dispatcher. * * Requires: *\li disp is valid. * * Returns: *\li The socket the dispatcher is using. */ isc_result_t dns_dispatch_getlocaladdress(dns_dispatch_t *disp, isc_sockaddr_t *addrp); /*%< * Return the local address for this dispatch. * This currently only works for dispatches using UDP sockets. * * Requires: *\li disp is valid. *\li addrp to be non null. * * Returns: *\li ISC_R_SUCCESS *\li ISC_R_NOTIMPLEMENTED */ void dns_dispatch_cancel(dns_dispatch_t *disp); /*%< * cancel outstanding clients * * Requires: *\li disp is valid. */ unsigned int dns_dispatch_getattributes(dns_dispatch_t *disp); /*%< * Return the attributes (DNS_DISPATCHATTR_xxx) of this dispatch. Only the * non-changeable attributes are expected to be referenced by the caller. * * Requires: *\li disp is valid. */ void dns_dispatch_changeattributes(dns_dispatch_t *disp, unsigned int attributes, unsigned int mask); /*%< * Set the bits described by "mask" to the corresponding values in * "attributes". * * That is: * * \code * new = (old & ~mask) | (attributes & mask) * \endcode * * This function has a side effect when #DNS_DISPATCHATTR_NOLISTEN changes. * When the flag becomes off, the dispatch will start receiving on the * corresponding socket. When the flag becomes on, receive events on the * corresponding socket will be canceled. * * Requires: *\li disp is valid. * *\li attributes are reasonable for the dispatch. That is, setting the UDP * attribute on a TCP socket isn't reasonable. */ void dns_dispatch_importrecv(dns_dispatch_t *disp, isc_event_t *event); /*%< * Inform the dispatcher of a socket receive. This is used for sockets * shared between dispatchers and clients. If the dispatcher fails to copy * or send the event, nothing happens. * * If the attribute DNS_DISPATCHATTR_NOLISTEN is not set, then * the dispatch is already handling a recv; return immediately. * * Requires: *\li disp is valid, and the attribute DNS_DISPATCHATTR_NOLISTEN is set. * event != NULL */ dns_dispatch_t * dns_dispatchset_get(dns_dispatchset_t *dset); /*%< * Retrieve the next dispatch from dispatch set 'dset', and increment * the round-robin counter. * * Requires: *\li dset != NULL */ isc_result_t dns_dispatchset_create(isc_mem_t *mctx, isc_socketmgr_t *sockmgr, isc_taskmgr_t *taskmgr, dns_dispatch_t *source, dns_dispatchset_t **dsetp, int n); /*%< * Given a valid dispatch 'source', create a dispatch set containing * 'n' UDP dispatches, with the remainder filled out by clones of the * source. * * Requires: *\li source is a valid UDP dispatcher *\li dsetp != NULL, *dsetp == NULL */ void dns_dispatchset_cancelall(dns_dispatchset_t *dset, isc_task_t *task); /*%< * Cancel socket operations for the dispatches in 'dset'. */ void dns_dispatchset_destroy(dns_dispatchset_t **dsetp); /*%< * Dereference all the dispatches in '*dsetp', free the dispatchset * memory, and set *dsetp to NULL. * * Requires: *\li dset is valid */ void dns_dispatch_setdscp(dns_dispatch_t *disp, isc_dscp_t dscp); isc_dscp_t dns_dispatch_getdscp(dns_dispatch_t *disp); /*%< * Set/get the DSCP value to be used when sending responses to clients, * as defined in the "listen-on" or "listen-on-v6" statements. * * Requires: *\li disp is valid. */ isc_result_t dns_dispatch_getnext(dns_dispentry_t *resp, dns_dispatchevent_t **sockevent); /*%< * Free the sockevent and trigger the sending of the next item off the * dispatch queue if present. * * Requires: *\li resp is valid *\li *sockevent to be valid */ ISC_LANG_ENDDECLS #endif /* DNS_DISPATCH_H */
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