555 lines
19 KiB
C
555 lines
19 KiB
C
/*
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* services/outside_network.h - listen to answers from the network
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*
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* Copyright (c) 2007, NLnet Labs. All rights reserved.
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*
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* This software is open source.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* Neither the name of the NLNET LABS nor the names of its contributors may
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* be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* \file
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*
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* This file has functions to send queries to authoritative servers,
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* and wait for the pending answer, with timeouts.
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*/
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#ifndef OUTSIDE_NETWORK_H
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#define OUTSIDE_NETWORK_H
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#include "util/rbtree.h"
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#include "util/netevent.h"
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#include "dnstap/dnstap_config.h"
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struct pending;
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struct pending_timeout;
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struct ub_randstate;
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struct pending_tcp;
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struct waiting_tcp;
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struct waiting_udp;
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struct infra_cache;
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struct port_comm;
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struct port_if;
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struct sldns_buffer;
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struct serviced_query;
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struct dt_env;
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/**
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* Send queries to outside servers and wait for answers from servers.
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* Contains answer-listen sockets.
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*/
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struct outside_network {
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/** Base for select calls */
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struct comm_base* base;
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/** pointer to time in seconds */
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time_t* now_secs;
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/** pointer to time in microseconds */
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struct timeval* now_tv;
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/** buffer shared by UDP connections, since there is only one
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datagram at any time. */
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struct sldns_buffer* udp_buff;
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/** serviced_callbacks malloc overhead when processing multiple
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* identical serviced queries to the same server. */
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size_t svcd_overhead;
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/** use x20 bits to encode additional ID random bits */
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int use_caps_for_id;
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/** outside network wants to quit. Stop queued msgs from sent. */
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int want_to_quit;
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/** number of unwanted replies received (for statistics) */
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size_t unwanted_replies;
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/** cumulative total of unwanted replies (for defense) */
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size_t unwanted_total;
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/** threshold when to take defensive action. If 0 then never. */
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size_t unwanted_threshold;
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/** what action to take, called when defensive action is needed */
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void (*unwanted_action)(void*);
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/** user param for action */
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void* unwanted_param;
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/** linked list of available commpoints, unused file descriptors,
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* for use as outgoing UDP ports. cp.fd=-1 in them. */
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struct port_comm* unused_fds;
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/** if udp is done */
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int do_udp;
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/** if udp is delay-closed (delayed answers do not meet closed port)*/
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int delayclose;
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/** timeout for delayclose */
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struct timeval delay_tv;
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/** array of outgoing IP4 interfaces */
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struct port_if* ip4_ifs;
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/** number of outgoing IP4 interfaces */
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int num_ip4;
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/** array of outgoing IP6 interfaces */
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struct port_if* ip6_ifs;
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/** number of outgoing IP6 interfaces */
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int num_ip6;
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/** pending udp queries waiting to be sent out, waiting for fd */
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struct pending* udp_wait_first;
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/** last pending udp query in list */
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struct pending* udp_wait_last;
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/** pending udp answers. sorted by id, addr */
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rbtree_t* pending;
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/** serviced queries, sorted by qbuf, addr, dnssec */
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rbtree_t* serviced;
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/** host cache, pointer but not owned by outnet. */
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struct infra_cache* infra;
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/** where to get random numbers */
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struct ub_randstate* rnd;
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/** ssl context to create ssl wrapped TCP with DNS connections */
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void* sslctx;
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#ifdef USE_DNSTAP
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/** dnstap environment */
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struct dt_env* dtenv;
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#endif
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/**
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* Array of tcp pending used for outgoing TCP connections.
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* Each can be used to establish a TCP connection with a server.
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* The file descriptors are -1 if they are free, and need to be
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* opened for the tcp connection. Can be used for ip4 and ip6.
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*/
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struct pending_tcp **tcp_conns;
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/** number of tcp communication points. */
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size_t num_tcp;
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/** number of tcp communication points in use. */
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size_t num_tcp_outgoing;
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/** list of tcp comm points that are free for use */
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struct pending_tcp* tcp_free;
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/** list of tcp queries waiting for a buffer */
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struct waiting_tcp* tcp_wait_first;
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/** last of waiting query list */
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struct waiting_tcp* tcp_wait_last;
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};
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/**
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* Outgoing interface. Ports available and currently used are tracked
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* per interface
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*/
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struct port_if {
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/** address ready to allocate new socket (except port no). */
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struct sockaddr_storage addr;
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/** length of addr field */
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socklen_t addrlen;
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/** the available ports array. These are unused.
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* Only the first total-inuse part is filled. */
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int* avail_ports;
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/** the total number of available ports (size of the array) */
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int avail_total;
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/** array of the commpoints currently in use.
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* allocated for max number of fds, first part in use. */
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struct port_comm** out;
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/** max number of fds, size of out array */
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int maxout;
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/** number of commpoints (and thus also ports) in use */
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int inuse;
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};
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/**
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* Outgoing commpoint for UDP port.
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*/
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struct port_comm {
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/** next in free list */
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struct port_comm* next;
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/** which port number (when in use) */
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int number;
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/** interface it is used in */
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struct port_if* pif;
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/** index in the out array of the interface */
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int index;
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/** number of outstanding queries on this port */
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int num_outstanding;
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/** UDP commpoint, fd=-1 if not in use */
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struct comm_point* cp;
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};
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/**
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* A query that has an answer pending for it.
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*/
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struct pending {
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/** redblacktree entry, key is the pending struct(id, addr). */
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rbnode_t node;
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/** the ID for the query. int so that a value out of range can
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* be used to signify a pending that is for certain not present in
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* the rbtree. (and for which deletion is safe). */
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unsigned int id;
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/** remote address. */
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struct sockaddr_storage addr;
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/** length of addr field in use. */
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socklen_t addrlen;
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/** comm point it was sent on (and reply must come back on). */
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struct port_comm* pc;
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/** timeout event */
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struct comm_timer* timer;
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/** callback for the timeout, error or reply to the message */
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comm_point_callback_t* cb;
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/** callback user argument */
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void* cb_arg;
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/** the outside network it is part of */
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struct outside_network* outnet;
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/** the corresponding serviced_query */
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struct serviced_query* sq;
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/*---- filled if udp pending is waiting -----*/
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/** next in waiting list. */
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struct pending* next_waiting;
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/** timeout in msec */
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int timeout;
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/** The query itself, the query packet to send. */
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uint8_t* pkt;
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/** length of query packet. */
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size_t pkt_len;
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};
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/**
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* Pending TCP query to server.
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*/
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struct pending_tcp {
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/** next in list of free tcp comm points, or NULL. */
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struct pending_tcp* next_free;
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/** the ID for the query; checked in reply */
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uint16_t id;
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/** tcp comm point it was sent on (and reply must come back on). */
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struct comm_point* c;
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/** the query being serviced, NULL if the pending_tcp is unused. */
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struct waiting_tcp* query;
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};
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/**
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* Query waiting for TCP buffer.
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*/
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struct waiting_tcp {
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/**
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* next in waiting list.
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* if pkt==0, this points to the pending_tcp structure.
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*/
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struct waiting_tcp* next_waiting;
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/** timeout event; timer keeps running whether the query is
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* waiting for a buffer or the tcp reply is pending */
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struct comm_timer* timer;
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/** the outside network it is part of */
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struct outside_network* outnet;
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/** remote address. */
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struct sockaddr_storage addr;
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/** length of addr field in use. */
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socklen_t addrlen;
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/**
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* The query itself, the query packet to send.
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* allocated after the waiting_tcp structure.
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* set to NULL when the query is serviced and it part of pending_tcp.
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* if this is NULL, the next_waiting points to the pending_tcp.
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*/
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uint8_t* pkt;
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/** length of query packet. */
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size_t pkt_len;
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/** callback for the timeout, error or reply to the message */
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comm_point_callback_t* cb;
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/** callback user argument */
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void* cb_arg;
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/** if it uses ssl upstream */
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int ssl_upstream;
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};
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/**
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* Callback to party interested in serviced query results.
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*/
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struct service_callback {
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/** next in callback list */
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struct service_callback* next;
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/** callback function */
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comm_point_callback_t* cb;
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/** user argument for callback function */
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void* cb_arg;
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};
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/** fallback size for fragmentation for EDNS in IPv4 */
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#define EDNS_FRAG_SIZE_IP4 1472
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/** fallback size for EDNS in IPv6, fits one fragment with ip6-tunnel-ids */
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#define EDNS_FRAG_SIZE_IP6 1232
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/**
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* Query service record.
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* Contains query and destination. UDP, TCP, EDNS are all tried.
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* complete with retries and timeouts. A number of interested parties can
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* receive a callback.
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*/
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struct serviced_query {
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/** The rbtree node, key is this record */
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rbnode_t node;
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/** The query that needs to be answered. Starts with flags u16,
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* then qdcount, ..., including qname, qtype, qclass. Does not include
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* EDNS record. */
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uint8_t* qbuf;
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/** length of qbuf. */
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size_t qbuflen;
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/** If an EDNS section is included, the DO/CD bit will be turned on. */
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int dnssec;
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/** We want signatures, or else the answer is likely useless */
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int want_dnssec;
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/** ignore capsforid */
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int nocaps;
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/** tcp upstream used, use tcp, or ssl_upstream for SSL */
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int tcp_upstream, ssl_upstream;
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/** where to send it */
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struct sockaddr_storage addr;
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/** length of addr field in use. */
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socklen_t addrlen;
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/** zone name, uncompressed domain name in wireformat */
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uint8_t* zone;
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/** length of zone name */
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size_t zonelen;
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/** qtype */
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int qtype;
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/** current status */
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enum serviced_query_status {
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/** initial status */
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serviced_initial,
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/** UDP with EDNS sent */
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serviced_query_UDP_EDNS,
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/** UDP without EDNS sent */
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serviced_query_UDP,
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/** TCP with EDNS sent */
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serviced_query_TCP_EDNS,
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/** TCP without EDNS sent */
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serviced_query_TCP,
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/** probe to test EDNS lameness (EDNS is dropped) */
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serviced_query_PROBE_EDNS,
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/** probe to test noEDNS0 (EDNS gives FORMERRorNOTIMP) */
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serviced_query_UDP_EDNS_fallback,
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/** probe to test TCP noEDNS0 (EDNS gives FORMERRorNOTIMP) */
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serviced_query_TCP_EDNS_fallback,
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/** send UDP query with EDNS1480 (or 1280) */
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serviced_query_UDP_EDNS_FRAG
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}
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/** variable with current status */
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status;
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/** true if serviced_query is scheduled for deletion already */
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int to_be_deleted;
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/** number of UDP retries */
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int retry;
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/** time last UDP was sent */
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struct timeval last_sent_time;
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/** rtt of last (UDP) message */
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int last_rtt;
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/** do we know edns probe status already, for UDP_EDNS queries */
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int edns_lame_known;
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/** outside network this is part of */
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struct outside_network* outnet;
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/** list of interested parties that need callback on results. */
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struct service_callback* cblist;
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/** the UDP or TCP query that is pending, see status which */
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void* pending;
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};
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/**
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* Create outside_network structure with N udp ports.
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* @param base: the communication base to use for event handling.
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* @param bufsize: size for network buffers.
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* @param num_ports: number of udp ports to open per interface.
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* @param ifs: interface names (or NULL for default interface).
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* These interfaces must be able to access all authoritative servers.
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* @param num_ifs: number of names in array ifs.
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* @param do_ip4: service IP4.
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* @param do_ip6: service IP6.
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* @param num_tcp: number of outgoing tcp buffers to preallocate.
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* @param infra: pointer to infra cached used for serviced queries.
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* @param rnd: stored to create random numbers for serviced queries.
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* @param use_caps_for_id: enable to use 0x20 bits to encode id randomness.
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* @param availports: array of available ports.
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* @param numavailports: number of available ports in array.
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* @param unwanted_threshold: when to take defensive action.
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* @param unwanted_action: the action to take.
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* @param unwanted_param: user parameter to action.
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* @param do_udp: if udp is done.
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* @param sslctx: context to create outgoing connections with (if enabled).
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* @param delayclose: if not 0, udp sockets are delayed before timeout closure.
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* msec to wait on timeouted udp sockets.
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* @param dtenv: environment to send dnstap events with (if enabled).
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* @return: the new structure (with no pending answers) or NULL on error.
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*/
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struct outside_network* outside_network_create(struct comm_base* base,
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size_t bufsize, size_t num_ports, char** ifs, int num_ifs,
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int do_ip4, int do_ip6, size_t num_tcp, struct infra_cache* infra,
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struct ub_randstate* rnd, int use_caps_for_id, int* availports,
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int numavailports, size_t unwanted_threshold,
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void (*unwanted_action)(void*), void* unwanted_param, int do_udp,
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void* sslctx, int delayclose, struct dt_env *dtenv);
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/**
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* Delete outside_network structure.
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* @param outnet: object to delete.
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*/
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void outside_network_delete(struct outside_network* outnet);
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/**
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* Prepare for quit. Sends no more queries, even if queued up.
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* @param outnet: object to prepare for removal
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*/
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void outside_network_quit_prepare(struct outside_network* outnet);
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/**
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* Send UDP query, create pending answer.
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* Changes the ID for the query to be random and unique for that destination.
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* @param sq: serviced query.
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* @param packet: wireformat query to send to destination.
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* @param timeout: in milliseconds from now.
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* @param callback: function to call on error, timeout or reply.
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* @param callback_arg: user argument for callback function.
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* @return: NULL on error for malloc or socket. Else the pending query object.
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*/
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struct pending* pending_udp_query(struct serviced_query* sq,
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struct sldns_buffer* packet, int timeout, comm_point_callback_t* callback,
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void* callback_arg);
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/**
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* Send TCP query. May wait for TCP buffer. Selects ID to be random, and
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* checks id.
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* @param sq: serviced query.
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* @param packet: wireformat query to send to destination. copied from.
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* @param timeout: in seconds from now.
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* Timer starts running now. Timer may expire if all buffers are used,
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* without any query been sent to the server yet.
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* @param callback: function to call on error, timeout or reply.
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* @param callback_arg: user argument for callback function.
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* @return: false on error for malloc or socket. Else the pending TCP object.
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*/
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struct waiting_tcp* pending_tcp_query(struct serviced_query* sq,
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struct sldns_buffer* packet, int timeout, comm_point_callback_t* callback,
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void* callback_arg);
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/**
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* Delete pending answer.
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* @param outnet: outside network the pending query is part of.
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* Internal feature: if outnet is NULL, p is not unlinked from rbtree.
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* @param p: deleted
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*/
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void pending_delete(struct outside_network* outnet, struct pending* p);
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/**
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* Perform a serviced query to the authoritative servers.
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* Duplicate efforts are detected, and EDNS, TCP and UDP retry is performed.
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* @param outnet: outside network, with rbtree of serviced queries.
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* @param qname: what qname to query.
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* @param qnamelen: length of qname in octets including 0 root label.
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* @param qtype: rrset type to query (host format)
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* @param qclass: query class. (host format)
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* @param flags: flags u16 (host format), includes opcode, CD bit.
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* @param dnssec: if set, DO bit is set in EDNS queries.
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* If the value includes BIT_CD, CD bit is set when in EDNS queries.
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* If the value includes BIT_DO, DO bit is set when in EDNS queries.
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* @param want_dnssec: signatures are needed, without EDNS the answer is
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* likely to be useless.
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* @param nocaps: ignore use_caps_for_id and use unperturbed qname.
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* @param tcp_upstream: use TCP for upstream queries.
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* @param ssl_upstream: use SSL for upstream queries.
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* @param callback: callback function.
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* @param callback_arg: user argument to callback function.
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* @param addr: to which server to send the query.
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* @param addrlen: length of addr.
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* @param zone: name of the zone of the delegation point. wireformat dname.
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This is the delegation point name for which the server is deemed
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authoritative.
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* @param zonelen: length of zone.
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* @param buff: scratch buffer to create query contents in. Empty on exit.
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* @return 0 on error, or pointer to serviced query that is used to answer
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* this serviced query may be shared with other callbacks as well.
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*/
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struct serviced_query* outnet_serviced_query(struct outside_network* outnet,
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uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
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uint16_t flags, int dnssec, int want_dnssec, int nocaps,
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int tcp_upstream, int ssl_upstream, struct sockaddr_storage* addr,
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socklen_t addrlen, uint8_t* zone, size_t zonelen,
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comm_point_callback_t* callback, void* callback_arg,
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struct sldns_buffer* buff);
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/**
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* Remove service query callback.
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* If that leads to zero callbacks, the query is completely cancelled.
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* @param sq: serviced query to adjust.
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* @param cb_arg: callback argument of callback that needs removal.
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* same as the callback_arg to outnet_serviced_query().
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*/
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void outnet_serviced_query_stop(struct serviced_query* sq, void* cb_arg);
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/**
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* Get memory size in use by outside network.
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* Counts buffers and outstanding query (serviced queries) malloced data.
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* @param outnet: outside network structure.
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* @return size in bytes.
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*/
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size_t outnet_get_mem(struct outside_network* outnet);
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/**
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* Get memory size in use by serviced query while it is servicing callbacks.
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* This takes into account the pre-deleted status of it; it will be deleted
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* when the callbacks are done.
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* @param sq: serviced query.
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* @return size in bytes.
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*/
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size_t serviced_get_mem(struct serviced_query* sq);
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/** callback for incoming udp answers from the network */
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int outnet_udp_cb(struct comm_point* c, void* arg, int error,
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struct comm_reply *reply_info);
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/** callback for pending tcp connections */
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int outnet_tcp_cb(struct comm_point* c, void* arg, int error,
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struct comm_reply *reply_info);
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/** callback for udp timeout */
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void pending_udp_timer_cb(void *arg);
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/** callback for udp delay for timeout */
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void pending_udp_timer_delay_cb(void *arg);
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/** callback for outgoing TCP timer event */
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void outnet_tcptimer(void* arg);
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/** callback for serviced query UDP answers */
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int serviced_udp_callback(struct comm_point* c, void* arg, int error,
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struct comm_reply* rep);
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|
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/** TCP reply or error callback for serviced queries */
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int serviced_tcp_callback(struct comm_point* c, void* arg, int error,
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struct comm_reply* rep);
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/** compare function of pending rbtree */
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int pending_cmp(const void* key1, const void* key2);
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|
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/** compare function of serviced query rbtree */
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int serviced_cmp(const void* key1, const void* key2);
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#endif /* OUTSIDE_NETWORK_H */
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