/*
* services/mesh.h - deal with mesh of query states and handle events for that.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \file
*
* This file contains functions to assist in dealing with a mesh of
* query states. This mesh is supposed to be thread-specific.
* It consists of query states (per qname, qtype, qclass) and connections
* between query states and the super and subquery states, and replies to
* send back to clients.
*/
#ifndef SERVICES_MESH_H
#define SERVICES_MESH_H
#include "util/rbtree.h"
#include "util/netevent.h"
#include "util/data/msgparse.h"
#include "util/module.h"
#include "services/modstack.h"
struct sldns_buffer;
struct mesh_state;
struct mesh_reply;
struct mesh_cb;
struct query_info;
struct reply_info;
struct outbound_entry;
struct timehist;
/**
* Maximum number of mesh state activations. Any more is likely an
* infinite loop in the module. It is then terminated.
*/
#define MESH_MAX_ACTIVATION 3000
/**
* Max number of references-to-references-to-references.. search size.
* Any more is treated like 'too large', and the creation of a new
* dependency is failed (so that no loops can be created).
*/
#define MESH_MAX_SUBSUB 1024
/**
* Mesh of query states
*/
struct mesh_area {
/** active module stack */
struct module_stack mods;
/** environment for new states */
struct module_env* env;
/** set of runnable queries (mesh_state.run_node) */
rbtree_t run;
/** rbtree of all current queries (mesh_state.node)*/
rbtree_t all;
/** count of the total number of mesh_reply entries */
size_t num_reply_addrs;
/** count of the number of mesh_states that have mesh_replies
* Because a state can send results to multiple reply addresses,
* this number must be equal or lower than num_reply_addrs. */
size_t num_reply_states;
/** number of mesh_states that have no mesh_replies, and also
* an empty set of super-states, thus are 'toplevel' or detached
* internal opportunistic queries */
size_t num_detached_states;
/** number of reply states in the forever list */
size_t num_forever_states;
/** max total number of reply states to have */
size_t max_reply_states;
/** max forever number of reply states to have */
size_t max_forever_states;
/** stats, cumulative number of reply states jostled out */
size_t stats_jostled;
/** stats, cumulative number of incoming client msgs dropped */
size_t stats_dropped;
/** number of replies sent */
size_t replies_sent;
/** sum of waiting times for the replies */
struct timeval replies_sum_wait;
/** histogram of time values */
struct timehist* histogram;
/** (extended stats) secure replies */
size_t ans_secure;
/** (extended stats) bogus replies */
size_t ans_bogus;
/** (extended stats) rcodes in replies */
size_t ans_rcode[16];
/** (extended stats) rcode nodata in replies */
size_t ans_nodata;
/** backup of query if other operations recurse and need the
* network buffers */
struct sldns_buffer* qbuf_bak;
/** double linked list of the run-to-completion query states.
* These are query states with a reply */
struct mesh_state* forever_first;
/** last entry in run forever list */
struct mesh_state* forever_last;
/** double linked list of the query states that can be jostled out
* by new queries if too old. These are query states with a reply */
struct mesh_state* jostle_first;
/** last entry in jostle list - this is the entry that is newest */
struct mesh_state* jostle_last;
/** timeout for jostling. if age is lower, it does not get jostled. */
struct timeval jostle_max;
};
/**
* A mesh query state
* Unique per qname, qtype, qclass (from the qstate).
* And RD / CD flag; in case a client turns it off.
* And priming queries are different from ordinary queries (because of hints).
*
* The entire structure is allocated in a region, this region is the qstate
* region. All parts (rbtree nodes etc) are also allocated in the region.
*/
struct mesh_state {
/** node in mesh_area all tree, key is this struct. Must be first. */
rbnode_t node;
/** node in mesh_area runnable tree, key is this struct */
rbnode_t run_node;
/** the query state. Note that the qinfo and query_flags
* may not change. */
struct module_qstate s;
/** the list of replies to clients for the results */
struct mesh_reply* reply_list;
/** the list of callbacks for the results */
struct mesh_cb* cb_list;
/** set of superstates (that want this state's result)
* contains struct mesh_state_ref* */
rbtree_t super_set;
/** set of substates (that this state needs to continue)
* contains struct mesh_state_ref* */
rbtree_t sub_set;
/** number of activations for the mesh state */
size_t num_activated;
/** previous in linked list for reply states */
struct mesh_state* prev;
/** next in linked list for reply states */
struct mesh_state* next;
/** if this state is in the forever list, jostle list, or neither */
enum mesh_list_select { mesh_no_list, mesh_forever_list,
mesh_jostle_list } list_select;
/** true if replies have been sent out (at end for alignment) */
uint8_t replies_sent;
};
/**
* Rbtree reference to a mesh_state.
* Used in super_set and sub_set.
*/
struct mesh_state_ref {
/** node in rbtree for set, key is this structure */
rbnode_t node;
/** the mesh state */
struct mesh_state* s;
};
/**
* Reply to a client
*/
struct mesh_reply {
/** next in reply list */
struct mesh_reply* next;
/** the query reply destination, packet buffer and where to send. */
struct comm_reply query_reply;
/** edns data from query */
struct edns_data edns;
/** the time when request was entered */
struct timeval start_time;
/** id of query, in network byteorder. */
uint16_t qid;
/** flags of query, for reply flags */
uint16_t qflags;
/** qname from this query. len same as mesh qinfo. */
uint8_t* qname;
};
/**
* Mesh result callback func.
* called as func(cb_arg, rcode, buffer_with_reply, security, why_bogus);
*/
typedef void (*mesh_cb_func_t)(void*, int, struct sldns_buffer*, enum sec_status,
char*);
/**
* Callback to result routine
*/
struct mesh_cb {
/** next in list */
struct mesh_cb* next;
/** edns data from query */
struct edns_data edns;
/** id of query, in network byteorder. */
uint16_t qid;
/** flags of query, for reply flags */
uint16_t qflags;
/** buffer for reply */
struct sldns_buffer* buf;
/** callback routine for results. if rcode != 0 buf has message.
* called as cb(cb_arg, rcode, buf, sec_state);
*/
mesh_cb_func_t cb;
/** user arg for callback */
void* cb_arg;
};
/* ------------------- Functions for worker -------------------- */
/**
* Allocate mesh, to empty.
* @param stack: module stack to activate, copied (as readonly reference).
* @param env: environment for new queries.
* @return mesh: the new mesh or NULL on error.
*/
struct mesh_area* mesh_create(struct module_stack* stack,
struct module_env* env);
/**
* Delete mesh, and all query states and replies in it.
* @param mesh: the mesh to delete.
*/
void mesh_delete(struct mesh_area* mesh);
/**
* New query incoming from clients. Create new query state if needed, and
* add mesh_reply to it. Returns error to client on malloc failures.
* Will run the mesh area queries to process if a new query state is created.
*
* @param mesh: the mesh.
* @param qinfo: query from client.
* @param qflags: flags from client query.
* @param edns: edns data from client query.
* @param rep: where to reply to.
* @param qid: query id to reply with.
*/
void mesh_new_client(struct mesh_area* mesh, struct query_info* qinfo,
uint16_t qflags, struct edns_data* edns, struct comm_reply* rep,
uint16_t qid);
/**
* New query with callback. Create new query state if needed, and
* add mesh_cb to it.
* Will run the mesh area queries to process if a new query state is created.
*
* @param mesh: the mesh.
* @param qinfo: query from client.
* @param qflags: flags from client query.
* @param edns: edns data from client query.
* @param buf: buffer for reply contents.
* @param qid: query id to reply with.
* @param cb: callback function.
* @param cb_arg: callback user arg.
* @return 0 on error.
*/
int mesh_new_callback(struct mesh_area* mesh, struct query_info* qinfo,
uint16_t qflags, struct edns_data* edns, struct sldns_buffer* buf,
uint16_t qid, mesh_cb_func_t cb, void* cb_arg);
/**
* New prefetch message. Create new query state if needed.
* Will run the mesh area queries to process if a new query state is created.
*
* @param mesh: the mesh.
* @param qinfo: query from client.
* @param qflags: flags from client query.
* @param leeway: TTL leeway what to expire earlier for this update.
*/
void mesh_new_prefetch(struct mesh_area* mesh, struct query_info* qinfo,
uint16_t qflags, time_t leeway);
/**
* Handle new event from the wire. A serviced query has returned.
* The query state will be made runnable, and the mesh_area will process
* query states until processing is complete.
*
* @param mesh: the query mesh.
* @param e: outbound entry, with query state to run and reply pointer.
* @param reply: the comm point reply info.
* @param what: NETEVENT_* error code (if not 0, what is wrong, TIMEOUT).
*/
void mesh_report_reply(struct mesh_area* mesh, struct outbound_entry* e,
struct comm_reply* reply, int what);
/* ------------------- Functions for module environment --------------- */
/**
* Detach-subqueries.
* Remove all sub-query references from this query state.
* Keeps super-references of those sub-queries correct.
* Updates stat items in mesh_area structure.
* @param qstate: used to find mesh state.
*/
void mesh_detach_subs(struct module_qstate* qstate);
/**
* Attach subquery.
* Creates it if it does not exist already.
* Keeps sub and super references correct.
* Performs a cycle detection - for double check - and fails if there is one.
* Also fails if the sub-sub-references become too large.
* Updates stat items in mesh_area structure.
* Pass if it is priming query or not.
* return:
* o if error (malloc) happened.
* o need to initialise the new state (module init; it is a new state).
* so that the next run of the query with this module is successful.
* o no init needed, attachment successful.
*
* @param qstate: the state to find mesh state, and that wants to receive
* the results from the new subquery.
* @param qinfo: what to query for (copied).
* @param qflags: what flags to use (RD / CD flag or not).
* @param prime: if it is a (stub) priming query.
* @param valrec: if it is a validation recursion query (lookup of key, DS).
* @param newq: If the new subquery needs initialisation, it is returned,
* otherwise NULL is returned.
* @return: false on error, true if success (and init may be needed).
*/
int mesh_attach_sub(struct module_qstate* qstate, struct query_info* qinfo,
uint16_t qflags, int prime, int valrec, struct module_qstate** newq);
/**
* Query state is done, send messages to reply entries.
* Encode messages using reply entry values and the querystate (with original
* qinfo), using given reply_info.
* Pass errcode != 0 if an error reply is needed.
* If no reply entries, nothing is done.
* Must be called before a module can module_finished or return module_error.
* The module must handle the super query states itself as well.
*
* @param mstate: mesh state that is done. return_rcode and return_msg
* are used for replies.
* return_rcode: if not 0 (NOERROR) an error is sent back (and
* return_msg is ignored).
* return_msg: reply to encode and send back to clients.
*/
void mesh_query_done(struct mesh_state* mstate);
/**
* Call inform_super for the super query states that are interested in the
* results from this query state. These can then be changed for error
* or results.
* Called when a module is module_finished or returns module_error.
* The super query states become runnable with event module_event_pass,
* it calls the current module for the super with the inform_super event.
*
* @param mesh: mesh area to add newly runnable modules to.
* @param mstate: the state that has results, used to find mesh state.
*/
void mesh_walk_supers(struct mesh_area* mesh, struct mesh_state* mstate);
/**
* Delete mesh state, cleanup and also rbtrees and so on.
* Will detach from all super/subnodes.
* @param qstate: to remove.
*/
void mesh_state_delete(struct module_qstate* qstate);
/* ------------------- Functions for mesh -------------------- */
/**
* Create and initialize a new mesh state and its query state
* Does not put the mesh state into rbtrees and so on.
* @param env: module environment to set.
* @param qinfo: query info that the mesh is for.
* @param qflags: flags for query (RD / CD flag).
* @param prime: if true, it is a priming query, set is_priming on mesh state.
* @param valrec: if true, it is a validation recursion query, and sets
* is_valrec on the mesh state.
* @return: new mesh state or NULL on allocation error.
*/
struct mesh_state* mesh_state_create(struct module_env* env,
struct query_info* qinfo, uint16_t qflags, int prime, int valrec);
/**
* Cleanup a mesh state and its query state. Does not do rbtree or
* reference cleanup.
* @param mstate: mesh state to cleanup. Its pointer may no longer be used
* afterwards. Cleanup rbtrees before calling this function.
*/
void mesh_state_cleanup(struct mesh_state* mstate);
/**
* Delete all mesh states from the mesh.
* @param mesh: the mesh area to clear
*/
void mesh_delete_all(struct mesh_area* mesh);
/**
* Find a mesh state in the mesh area. Pass relevant flags.
*
* @param mesh: the mesh area to look in.
* @param qinfo: what query
* @param qflags: if RD / CD bit is set or not.
* @param prime: if it is a priming query.
* @param valrec: if it is a validation-recursion query.
* @return: mesh state or NULL if not found.
*/
struct mesh_state* mesh_area_find(struct mesh_area* mesh,
struct query_info* qinfo, uint16_t qflags, int prime, int valrec);
/**
* Setup attachment super/sub relation between super and sub mesh state.
* The relation must not be present when calling the function.
* Does not update stat items in mesh_area.
* @param super: super state.
* @param sub: sub state.
* @return: 0 on alloc error.
*/
int mesh_state_attachment(struct mesh_state* super, struct mesh_state* sub);
/**
* Create new reply structure and attach it to a mesh state.
* Does not update stat items in mesh area.
* @param s: the mesh state.
* @param edns: edns data for reply (bufsize).
* @param rep: comm point reply info.
* @param qid: ID of reply.
* @param qflags: original query flags.
* @param qname: original query name.
* @return: 0 on alloc error.
*/
int mesh_state_add_reply(struct mesh_state* s, struct edns_data* edns,
struct comm_reply* rep, uint16_t qid, uint16_t qflags, uint8_t* qname);
/**
* Create new callback structure and attach it to a mesh state.
* Does not update stat items in mesh area.
* @param s: the mesh state.
* @param edns: edns data for reply (bufsize).
* @param buf: buffer for reply
* @param cb: callback to call with results.
* @param cb_arg: callback user arg.
* @param qid: ID of reply.
* @param qflags: original query flags.
* @return: 0 on alloc error.
*/
int mesh_state_add_cb(struct mesh_state* s, struct edns_data* edns,
struct sldns_buffer* buf, mesh_cb_func_t cb, void* cb_arg, uint16_t qid,
uint16_t qflags);
/**
* Run the mesh. Run all runnable mesh states. Which can create new
* runnable mesh states. Until completion. Automatically called by
* mesh_report_reply and mesh_new_client as needed.
* @param mesh: mesh area.
* @param mstate: first mesh state to run.
* @param ev: event the mstate. Others get event_pass.
* @param e: if a reply, its outbound entry.
*/
void mesh_run(struct mesh_area* mesh, struct mesh_state* mstate,
enum module_ev ev, struct outbound_entry* e);
/**
* Print some stats about the mesh to the log.
* @param mesh: the mesh to print it for.
* @param str: descriptive string to go with it.
*/
void mesh_stats(struct mesh_area* mesh, const char* str);
/**
* Clear the stats that the mesh keeps (number of queries serviced)
* @param mesh: the mesh
*/
void mesh_stats_clear(struct mesh_area* mesh);
/**
* Print all the states in the mesh to the log.
* @param mesh: the mesh to print all states of.
*/
void mesh_log_list(struct mesh_area* mesh);
/**
* Calculate memory size in use by mesh and all queries inside it.
* @param mesh: the mesh to examine.
* @return size in bytes.
*/
size_t mesh_get_mem(struct mesh_area* mesh);
/**
* Find cycle; see if the given mesh is in the targets sub, or sub-sub, ...
* trees.
* If the sub-sub structure is too large, it returns 'a cycle'=2.
* @param qstate: given mesh querystate.
* @param qinfo: query info for dependency.
* @param flags: query flags of dependency.
* @param prime: if dependency is a priming query or not.
* @param valrec: if it is a validation recursion query (lookup of key, DS).
* @return true if the name,type,class exists and the given qstate mesh exists
* as a dependency of that name. Thus if qstate becomes dependent on
* name,type,class then a cycle is created, this is return value 1.
* Too large to search is value 2 (also true).
*/
int mesh_detect_cycle(struct module_qstate* qstate, struct query_info* qinfo,
uint16_t flags, int prime, int valrec);
/** compare two mesh_states */
int mesh_state_compare(const void* ap, const void* bp);
/** compare two mesh references */
int mesh_state_ref_compare(const void* ap, const void* bp);
/**
* Make space for another recursion state for a reply in the mesh
* @param mesh: mesh area
* @param qbuf: query buffer to save if recursion is invoked to make space.
* This buffer is necessary, because the following sequence in calls
* can result in an overwrite of the incoming query:
* delete_other_mesh_query - iter_clean - serviced_delete - waiting
* udp query is sent - on error callback - callback sends SERVFAIL reply
* over the same network channel, and shared UDP buffer is overwritten.
* You can pass NULL if there is no buffer that must be backed up.
* @return false if no space is available.
*/
int mesh_make_new_space(struct mesh_area* mesh, struct sldns_buffer* qbuf);
/**
* Insert mesh state into a double linked list. Inserted at end.
* @param m: mesh state.
* @param fp: pointer to the first-elem-pointer of the list.
* @param lp: pointer to the last-elem-pointer of the list.
*/
void mesh_list_insert(struct mesh_state* m, struct mesh_state** fp,
struct mesh_state** lp);
/**
* Remove mesh state from a double linked list. Remove from any position.
* @param m: mesh state.
* @param fp: pointer to the first-elem-pointer of the list.
* @param lp: pointer to the last-elem-pointer of the list.
*/
void mesh_list_remove(struct mesh_state* m, struct mesh_state** fp,
struct mesh_state** lp);
#endif /* SERVICES_MESH_H */
