diff options
Diffstat (limited to 'lib/dns/dispatch.c')
| -rw-r--r-- | lib/dns/dispatch.c | 2674 |
1 files changed, 2674 insertions, 0 deletions
diff --git a/lib/dns/dispatch.c b/lib/dns/dispatch.c new file mode 100644 index 0000000..f3ef091 --- /dev/null +++ b/lib/dns/dispatch.c @@ -0,0 +1,2674 @@ +/* + * Copyright (C) 2004-2007 Internet Systems Consortium, Inc. ("ISC") + * Copyright (C) 1999-2003 Internet Software Consortium. + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH + * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, + * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM + * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE + * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + * PERFORMANCE OF THIS SOFTWARE. + */ + +/* $Id: dispatch.c,v 1.116.18.19 2007/08/28 07:20:04 tbox Exp $ */ + +/*! \file */ + +#include <config.h> + +#include <stdlib.h> +#include <sys/types.h> +#include <unistd.h> + +#include <isc/entropy.h> +#include <isc/mem.h> +#include <isc/mutex.h> +#include <isc/print.h> +#include <isc/string.h> +#include <isc/task.h> +#include <isc/time.h> +#include <isc/util.h> + +#include <dns/acl.h> +#include <dns/dispatch.h> +#include <dns/events.h> +#include <dns/log.h> +#include <dns/message.h> +#include <dns/portlist.h> +#include <dns/tcpmsg.h> +#include <dns/types.h> + +typedef ISC_LIST(dns_dispentry_t) dns_displist_t; + +typedef struct dns_nsid { + isc_uint16_t nsid_state; + isc_uint16_t *nsid_vtable; + isc_uint16_t *nsid_pool; + isc_uint16_t nsid_a1, nsid_a2, nsid_a3; + isc_uint16_t nsid_c1, nsid_c2, nsid_c3; + isc_uint16_t nsid_state2; + isc_boolean_t nsid_usepool; +} dns_nsid_t; + +typedef struct dns_qid { + unsigned int magic; + unsigned int qid_nbuckets; /*%< hash table size */ + unsigned int qid_increment; /*%< id increment on collision */ + isc_mutex_t lock; + dns_nsid_t nsid; + dns_displist_t *qid_table; /*%< the table itself */ +} dns_qid_t; + +struct dns_dispatchmgr { + /* Unlocked. */ + unsigned int magic; + isc_mem_t *mctx; + dns_acl_t *blackhole; + dns_portlist_t *portlist; + + /* Locked by "lock". */ + isc_mutex_t lock; + unsigned int state; + ISC_LIST(dns_dispatch_t) list; + + /* locked by buffer lock */ + dns_qid_t *qid; + isc_mutex_t buffer_lock; + unsigned int buffers; /*%< allocated buffers */ + unsigned int buffersize; /*%< size of each buffer */ + unsigned int maxbuffers; /*%< max buffers */ + + /* Locked internally. */ + isc_mutex_t pool_lock; + isc_mempool_t *epool; /*%< memory pool for events */ + isc_mempool_t *rpool; /*%< memory pool for replies */ + isc_mempool_t *dpool; /*%< dispatch allocations */ + isc_mempool_t *bpool; /*%< memory pool for buffers */ + + isc_entropy_t *entropy; /*%< entropy source */ +}; + +#define MGR_SHUTTINGDOWN 0x00000001U +#define MGR_IS_SHUTTINGDOWN(l) (((l)->state & MGR_SHUTTINGDOWN) != 0) + +#define IS_PRIVATE(d) (((d)->attributes & DNS_DISPATCHATTR_PRIVATE) != 0) + +struct dns_dispentry { + unsigned int magic; + dns_dispatch_t *disp; + dns_messageid_t id; + unsigned int bucket; + isc_sockaddr_t host; + isc_task_t *task; + isc_taskaction_t action; + void *arg; + isc_boolean_t item_out; + ISC_LIST(dns_dispatchevent_t) items; + ISC_LINK(dns_dispentry_t) link; +}; + +#define INVALID_BUCKET (0xffffdead) + +struct dns_dispatch { + /* Unlocked. */ + unsigned int magic; /*%< magic */ + dns_dispatchmgr_t *mgr; /*%< dispatch manager */ + isc_task_t *task; /*%< internal task */ + isc_socket_t *socket; /*%< isc socket attached to */ + isc_sockaddr_t local; /*%< local address */ + unsigned int maxrequests; /*%< max requests */ + isc_event_t *ctlevent; + + /*% Locked by mgr->lock. */ + ISC_LINK(dns_dispatch_t) link; + + /* Locked by "lock". */ + isc_mutex_t lock; /*%< locks all below */ + isc_sockettype_t socktype; + unsigned int attributes; + unsigned int refcount; /*%< number of users */ + dns_dispatchevent_t *failsafe_ev; /*%< failsafe cancel event */ + unsigned int shutting_down : 1, + shutdown_out : 1, + connected : 1, + tcpmsg_valid : 1, + recv_pending : 1; /*%< is a recv() pending? */ + isc_result_t shutdown_why; + unsigned int requests; /*%< how many requests we have */ + unsigned int tcpbuffers; /*%< allocated buffers */ + dns_tcpmsg_t tcpmsg; /*%< for tcp streams */ + dns_qid_t *qid; +}; + +#define QID_MAGIC ISC_MAGIC('Q', 'i', 'd', ' ') +#define VALID_QID(e) ISC_MAGIC_VALID((e), QID_MAGIC) + +#define RESPONSE_MAGIC ISC_MAGIC('D', 'r', 's', 'p') +#define VALID_RESPONSE(e) ISC_MAGIC_VALID((e), RESPONSE_MAGIC) + +#define DISPATCH_MAGIC ISC_MAGIC('D', 'i', 's', 'p') +#define VALID_DISPATCH(e) ISC_MAGIC_VALID((e), DISPATCH_MAGIC) + +#define DNS_DISPATCHMGR_MAGIC ISC_MAGIC('D', 'M', 'g', 'r') +#define VALID_DISPATCHMGR(e) ISC_MAGIC_VALID((e), DNS_DISPATCHMGR_MAGIC) + +#define DNS_QID(disp) ((disp)->socktype == isc_sockettype_tcp) ? \ + (disp)->qid : (disp)->mgr->qid +/* + * Statics. + */ +static dns_dispentry_t *bucket_search(dns_qid_t *, isc_sockaddr_t *, + dns_messageid_t, unsigned int); +static isc_boolean_t destroy_disp_ok(dns_dispatch_t *); +static void destroy_disp(isc_task_t *task, isc_event_t *event); +static void udp_recv(isc_task_t *, isc_event_t *); +static void tcp_recv(isc_task_t *, isc_event_t *); +static void startrecv(dns_dispatch_t *); +static dns_messageid_t dns_randomid(dns_nsid_t *); +static isc_uint32_t dns_hash(dns_qid_t *, isc_sockaddr_t *, dns_messageid_t); +static void free_buffer(dns_dispatch_t *disp, void *buf, unsigned int len); +static void *allocate_udp_buffer(dns_dispatch_t *disp); +static inline void free_event(dns_dispatch_t *disp, dns_dispatchevent_t *ev); +static inline dns_dispatchevent_t *allocate_event(dns_dispatch_t *disp); +static void do_cancel(dns_dispatch_t *disp); +static dns_dispentry_t *linear_first(dns_qid_t *disp); +static dns_dispentry_t *linear_next(dns_qid_t *disp, + dns_dispentry_t *resp); +static void dispatch_free(dns_dispatch_t **dispp); +static isc_result_t dispatch_createudp(dns_dispatchmgr_t *mgr, + isc_socketmgr_t *sockmgr, + isc_taskmgr_t *taskmgr, + isc_sockaddr_t *localaddr, + unsigned int maxrequests, + unsigned int attributes, + dns_dispatch_t **dispp); +static isc_boolean_t destroy_mgr_ok(dns_dispatchmgr_t *mgr); +static void destroy_mgr(dns_dispatchmgr_t **mgrp); +static isc_result_t qid_allocate(dns_dispatchmgr_t *mgr, unsigned int buckets, + unsigned int increment, isc_boolean_t usepool, + dns_qid_t **qidp); +static void qid_destroy(isc_mem_t *mctx, dns_qid_t **qidp); +static isc_uint16_t nsid_next(dns_nsid_t *nsid); +static isc_result_t nsid_init(isc_mem_t *mctx, dns_nsid_t *nsid, isc_boolean_t usepool); +static void nsid_destroy(isc_mem_t *mctx, dns_nsid_t *nsid); + +#define LVL(x) ISC_LOG_DEBUG(x) + +static void +mgr_log(dns_dispatchmgr_t *mgr, int level, const char *fmt, ...) + ISC_FORMAT_PRINTF(3, 4); + +static void +mgr_log(dns_dispatchmgr_t *mgr, int level, const char *fmt, ...) { + char msgbuf[2048]; + va_list ap; + + if (! isc_log_wouldlog(dns_lctx, level)) + return; + + va_start(ap, fmt); + vsnprintf(msgbuf, sizeof(msgbuf), fmt, ap); + va_end(ap); + + isc_log_write(dns_lctx, + DNS_LOGCATEGORY_DISPATCH, DNS_LOGMODULE_DISPATCH, + level, "dispatchmgr %p: %s", mgr, msgbuf); +} + +static void +dispatch_log(dns_dispatch_t *disp, int level, const char *fmt, ...) + ISC_FORMAT_PRINTF(3, 4); + +static void +dispatch_log(dns_dispatch_t *disp, int level, const char *fmt, ...) { + char msgbuf[2048]; + va_list ap; + + if (! isc_log_wouldlog(dns_lctx, level)) + return; + + va_start(ap, fmt); + vsnprintf(msgbuf, sizeof(msgbuf), fmt, ap); + va_end(ap); + + isc_log_write(dns_lctx, + DNS_LOGCATEGORY_DISPATCH, DNS_LOGMODULE_DISPATCH, + level, "dispatch %p: %s", disp, msgbuf); +} + +static void +request_log(dns_dispatch_t *disp, dns_dispentry_t *resp, + int level, const char *fmt, ...) + ISC_FORMAT_PRINTF(4, 5); + +static void +request_log(dns_dispatch_t *disp, dns_dispentry_t *resp, + int level, const char *fmt, ...) +{ + char msgbuf[2048]; + char peerbuf[256]; + va_list ap; + + if (! isc_log_wouldlog(dns_lctx, level)) + return; + + va_start(ap, fmt); + vsnprintf(msgbuf, sizeof(msgbuf), fmt, ap); + va_end(ap); + + if (VALID_RESPONSE(resp)) { + isc_sockaddr_format(&resp->host, peerbuf, sizeof(peerbuf)); + isc_log_write(dns_lctx, DNS_LOGCATEGORY_DISPATCH, + DNS_LOGMODULE_DISPATCH, level, + "dispatch %p response %p %s: %s", disp, resp, + peerbuf, msgbuf); + } else { + isc_log_write(dns_lctx, DNS_LOGCATEGORY_DISPATCH, + DNS_LOGMODULE_DISPATCH, level, + "dispatch %p req/resp %p: %s", disp, resp, + msgbuf); + } +} + +/* + * Return an unpredictable message ID. + */ +static dns_messageid_t +dns_randomid(dns_nsid_t *nsid) { + isc_uint32_t id; + + id = nsid_next(nsid); + + return ((dns_messageid_t)id); +} + +/* + * Return a hash of the destination and message id. + */ +static isc_uint32_t +dns_hash(dns_qid_t *qid, isc_sockaddr_t *dest, dns_messageid_t id) { + unsigned int ret; + + ret = isc_sockaddr_hash(dest, ISC_TRUE); + ret ^= id; + ret %= qid->qid_nbuckets; + + INSIST(ret < qid->qid_nbuckets); + + return (ret); +} + +/* + * Find the first entry in 'qid'. Returns NULL if there are no entries. + */ +static dns_dispentry_t * +linear_first(dns_qid_t *qid) { + dns_dispentry_t *ret; + unsigned int bucket; + + bucket = 0; + + while (bucket < qid->qid_nbuckets) { + ret = ISC_LIST_HEAD(qid->qid_table[bucket]); + if (ret != NULL) + return (ret); + bucket++; + } + + return (NULL); +} + +/* + * Find the next entry after 'resp' in 'qid'. Return NULL if there are + * no more entries. + */ +static dns_dispentry_t * +linear_next(dns_qid_t *qid, dns_dispentry_t *resp) { + dns_dispentry_t *ret; + unsigned int bucket; + + ret = ISC_LIST_NEXT(resp, link); + if (ret != NULL) + return (ret); + + bucket = resp->bucket; + bucket++; + while (bucket < qid->qid_nbuckets) { + ret = ISC_LIST_HEAD(qid->qid_table[bucket]); + if (ret != NULL) + return (ret); + bucket++; + } + + return (NULL); +} + +/* + * The dispatch must be locked. + */ +static isc_boolean_t +destroy_disp_ok(dns_dispatch_t *disp) +{ + if (disp->refcount != 0) + return (ISC_FALSE); + + if (disp->recv_pending != 0) + return (ISC_FALSE); + + if (disp->shutting_down == 0) + return (ISC_FALSE); + + return (ISC_TRUE); +} + + +/* + * Called when refcount reaches 0 (and safe to destroy). + * + * The dispatcher must not be locked. + * The manager must be locked. + */ +static void +destroy_disp(isc_task_t *task, isc_event_t *event) { + dns_dispatch_t *disp; + dns_dispatchmgr_t *mgr; + isc_boolean_t killmgr; + + INSIST(event->ev_type == DNS_EVENT_DISPATCHCONTROL); + + UNUSED(task); + + disp = event->ev_arg; + mgr = disp->mgr; + + LOCK(&mgr->lock); + ISC_LIST_UNLINK(mgr->list, disp, link); + + dispatch_log(disp, LVL(90), + "shutting down; detaching from sock %p, task %p", + disp->socket, disp->task); + + isc_socket_detach(&disp->socket); + isc_task_detach(&disp->task); + isc_event_free(&event); + + dispatch_free(&disp); + + killmgr = destroy_mgr_ok(mgr); + UNLOCK(&mgr->lock); + if (killmgr) + destroy_mgr(&mgr); +} + + +/* + * Find an entry for query ID 'id' and socket address 'dest' in 'qid'. + * Return NULL if no such entry exists. + */ +static dns_dispentry_t * +bucket_search(dns_qid_t *qid, isc_sockaddr_t *dest, dns_messageid_t id, + unsigned int bucket) +{ + dns_dispentry_t *res; + + REQUIRE(bucket < qid->qid_nbuckets); + + res = ISC_LIST_HEAD(qid->qid_table[bucket]); + + while (res != NULL) { + if ((res->id == id) && isc_sockaddr_equal(dest, &res->host)) + return (res); + res = ISC_LIST_NEXT(res, link); + } + + return (NULL); +} + +static void +free_buffer(dns_dispatch_t *disp, void *buf, unsigned int len) { + INSIST(buf != NULL && len != 0); + + + switch (disp->socktype) { + case isc_sockettype_tcp: + INSIST(disp->tcpbuffers > 0); + disp->tcpbuffers--; + isc_mem_put(disp->mgr->mctx, buf, len); + break; + case isc_sockettype_udp: + LOCK(&disp->mgr->buffer_lock); + INSIST(disp->mgr->buffers > 0); + INSIST(len == disp->mgr->buffersize); + disp->mgr->buffers--; + isc_mempool_put(disp->mgr->bpool, buf); + UNLOCK(&disp->mgr->buffer_lock); + break; + default: + INSIST(0); + break; + } +} + +static void * +allocate_udp_buffer(dns_dispatch_t *disp) { + void *temp; + + LOCK(&disp->mgr->buffer_lock); + temp = isc_mempool_get(disp->mgr->bpool); + + if (temp != NULL) + disp->mgr->buffers++; + UNLOCK(&disp->mgr->buffer_lock); + + return (temp); +} + +static inline void +free_event(dns_dispatch_t *disp, dns_dispatchevent_t *ev) { + if (disp->failsafe_ev == ev) { + INSIST(disp->shutdown_out == 1); + disp->shutdown_out = 0; + + return; + } + + isc_mempool_put(disp->mgr->epool, ev); +} + +static inline dns_dispatchevent_t * +allocate_event(dns_dispatch_t *disp) { + dns_dispatchevent_t *ev; + + ev = isc_mempool_get(disp->mgr->epool); + if (ev == NULL) + return (NULL); + ISC_EVENT_INIT(ev, sizeof(*ev), 0, NULL, 0, + NULL, NULL, NULL, NULL, NULL); + + return (ev); +} + +/* + * General flow: + * + * If I/O result == CANCELED or error, free the buffer. + * + * If query, free the buffer, restart. + * + * If response: + * Allocate event, fill in details. + * If cannot allocate, free buffer, restart. + * find target. If not found, free buffer, restart. + * if event queue is not empty, queue. else, send. + * restart. + */ +static void +udp_recv(isc_task_t *task, isc_event_t *ev_in) { + isc_socketevent_t *ev = (isc_socketevent_t *)ev_in; + dns_dispatch_t *disp = ev_in->ev_arg; + dns_messageid_t id; + isc_result_t dres; + isc_buffer_t source; + unsigned int flags; + dns_dispentry_t *resp; + dns_dispatchevent_t *rev; + unsigned int bucket; + isc_boolean_t killit; + isc_boolean_t queue_response; + dns_dispatchmgr_t *mgr; + dns_qid_t *qid; + isc_netaddr_t netaddr; + int match; + + UNUSED(task); + + LOCK(&disp->lock); + + mgr = disp->mgr; + qid = mgr->qid; + + dispatch_log(disp, LVL(90), + "got packet: requests %d, buffers %d, recvs %d", + disp->requests, disp->mgr->buffers, disp->recv_pending); + + if (ev->ev_type == ISC_SOCKEVENT_RECVDONE) { + /* + * Unless the receive event was imported from a listening + * interface, in which case the event type is + * DNS_EVENT_IMPORTRECVDONE, receive operation must be pending. + */ + INSIST(disp->recv_pending != 0); + disp->recv_pending = 0; + } + + if (disp->shutting_down) { + /* + * This dispatcher is shutting down. + */ + free_buffer(disp, ev->region.base, ev->region.length); + + isc_event_free(&ev_in); + ev = NULL; + + killit = destroy_disp_ok(disp); + UNLOCK(&disp->lock); + if (killit) + isc_task_send(disp->task, &disp->ctlevent); + + return; + } + + if (ev->result != ISC_R_SUCCESS) { + free_buffer(disp, ev->region.base, ev->region.length); + + if (ev->result != ISC_R_CANCELED) + dispatch_log(disp, ISC_LOG_ERROR, + "odd socket result in udp_recv(): %s", + isc_result_totext(ev->result)); + + UNLOCK(&disp->lock); + isc_event_free(&ev_in); + return; + } + + /* + * If this is from a blackholed address, drop it. + */ + isc_netaddr_fromsockaddr(&netaddr, &ev->address); + if (disp->mgr->blackhole != NULL && + dns_acl_match(&netaddr, NULL, disp->mgr->blackhole, + NULL, &match, NULL) == ISC_R_SUCCESS && + match > 0) + { + if (isc_log_wouldlog(dns_lctx, LVL(10))) { + char netaddrstr[ISC_NETADDR_FORMATSIZE]; + isc_netaddr_format(&netaddr, netaddrstr, + sizeof(netaddrstr)); + dispatch_log(disp, LVL(10), + "blackholed packet from %s", + netaddrstr); + } + free_buffer(disp, ev->region.base, ev->region.length); + goto restart; + } + + /* + * Peek into the buffer to see what we can see. + */ + isc_buffer_init(&source, ev->region.base, ev->region.length); + isc_buffer_add(&source, ev->n); + dres = dns_message_peekheader(&source, &id, &flags); + if (dres != ISC_R_SUCCESS) { + free_buffer(disp, ev->region.base, ev->region.length); + dispatch_log(disp, LVL(10), "got garbage packet"); + goto restart; + } + + dispatch_log(disp, LVL(92), + "got valid DNS message header, /QR %c, id %u", + ((flags & DNS_MESSAGEFLAG_QR) ? '1' : '0'), id); + + /* + * Look at flags. If query, drop it. If response, + * look to see where it goes. + */ + queue_response = ISC_FALSE; + if ((flags & DNS_MESSAGEFLAG_QR) == 0) { + /* query */ + free_buffer(disp, ev->region.base, ev->region.length); + goto restart; + } + + dns_dispatch_hash(&ev->timestamp, sizeof(&ev->timestamp)); + dns_dispatch_hash(ev->region.base, ev->region.length); + + /* response */ + bucket = dns_hash(qid, &ev->address, id); + LOCK(&qid->lock); + resp = bucket_search(qid, &ev->address, id, bucket); + dispatch_log(disp, LVL(90), + "search for response in bucket %d: %s", + bucket, (resp == NULL ? "not found" : "found")); + + if (resp == NULL) { + free_buffer(disp, ev->region.base, ev->region.length); + goto unlock; + } + + /* + * Now that we have the original dispatch the query was sent + * from check that the address and port the response was + * sent to make sense. + */ + if (disp != resp->disp) { + isc_sockaddr_t a1; + isc_sockaddr_t a2; + + /* + * Check that the socket types and ports match. + */ + if (disp->socktype != resp->disp->socktype || + isc_sockaddr_getport(&disp->local) != + isc_sockaddr_getport(&resp->disp->local)) { + free_buffer(disp, ev->region.base, ev->region.length); + goto unlock; + } + + /* + * If both dispatches are bound to an address then fail as + * the addresses can't be equal (enforced by the IP stack). + * + * Note under Linux a packet can be sent out via IPv4 socket + * and the response be received via a IPv6 socket. + * + * Requests sent out via IPv6 should always come back in + * via IPv6. + */ + if (isc_sockaddr_pf(&resp->disp->local) == PF_INET6 && + isc_sockaddr_pf(&disp->local) != PF_INET6) { + free_buffer(disp, ev->region.base, ev->region.length); + goto unlock; + } + isc_sockaddr_anyofpf(&a1, isc_sockaddr_pf(&resp->disp->local)); + isc_sockaddr_anyofpf(&a2, isc_sockaddr_pf(&disp->local)); + if (!isc_sockaddr_eqaddr(&a1, &resp->disp->local) && + !isc_sockaddr_eqaddr(&a2, &disp->local)) { + free_buffer(disp, ev->region.base, ev->region.length); + goto unlock; + } + } + + queue_response = resp->item_out; + rev = allocate_event(resp->disp); + if (rev == NULL) { + free_buffer(disp, ev->region.base, ev->region.length); + goto unlock; + } + + /* + * At this point, rev contains the event we want to fill in, and + * resp contains the information on the place to send it to. + * Send the event off. + */ + isc_buffer_init(&rev->buffer, ev->region.base, ev->region.length); + isc_buffer_add(&rev->buffer, ev->n); + rev->result = ISC_R_SUCCESS; + rev->id = id; + rev->addr = ev->address; + rev->pktinfo = ev->pktinfo; + rev->attributes = ev->attributes; + if (queue_response) { + ISC_LIST_APPEND(resp->items, rev, ev_link); + } else { + ISC_EVENT_INIT(rev, sizeof(*rev), 0, NULL, + DNS_EVENT_DISPATCH, + resp->action, resp->arg, resp, NULL, NULL); + request_log(disp, resp, LVL(90), + "[a] Sent event %p buffer %p len %d to task %p", + rev, rev->buffer.base, rev->buffer.length, + resp->task); + resp->item_out = ISC_TRUE; + isc_task_send(resp->task, ISC_EVENT_PTR(&rev)); + } + unlock: + UNLOCK(&qid->lock); + + /* + * Restart recv() to get the next packet. + */ + restart: + startrecv(disp); + + UNLOCK(&disp->lock); + + isc_event_free(&ev_in); +} + +/* + * General flow: + * + * If I/O result == CANCELED, EOF, or error, notify everyone as the + * various queues drain. + * + * If query, restart. + * + * If response: + * Allocate event, fill in details. + * If cannot allocate, restart. + * find target. If not found, restart. + * if event queue is not empty, queue. else, send. + * restart. + */ +static void +tcp_recv(isc_task_t *task, isc_event_t *ev_in) { + dns_dispatch_t *disp = ev_in->ev_arg; + dns_tcpmsg_t *tcpmsg = &disp->tcpmsg; + dns_messageid_t id; + isc_result_t dres; + unsigned int flags; + dns_dispentry_t *resp; + dns_dispatchevent_t *rev; + unsigned int bucket; + isc_boolean_t killit; + isc_boolean_t queue_response; + dns_qid_t *qid; + int level; + char buf[ISC_SOCKADDR_FORMATSIZE]; + + UNUSED(task); + + REQUIRE(VALID_DISPATCH(disp)); + + qid = disp->qid; + + dispatch_log(disp, LVL(90), + "got TCP packet: requests %d, buffers %d, recvs %d", + disp->requests, disp->tcpbuffers, disp->recv_pending); + + LOCK(&disp->lock); + + INSIST(disp->recv_pending != 0); + disp->recv_pending = 0; + + if (disp->refcount == 0) { + /* + * This dispatcher is shutting down. Force cancelation. + */ + tcpmsg->result = ISC_R_CANCELED; + } + + if (tcpmsg->result != ISC_R_SUCCESS) { + switch (tcpmsg->result) { + case ISC_R_CANCELED: + break; + + case ISC_R_EOF: + dispatch_log(disp, LVL(90), "shutting down on EOF"); + do_cancel(disp); + break; + + case ISC_R_CONNECTIONRESET: + level = ISC_LOG_INFO; + goto logit; + + default: + level = ISC_LOG_ERROR; + logit: + isc_sockaddr_format(&tcpmsg->address, buf, sizeof(buf)); + dispatch_log(disp, level, "shutting down due to TCP " + "receive error: %s: %s", buf, + isc_result_totext(tcpmsg->result)); + do_cancel(disp); + break; + } + + /* + * The event is statically allocated in the tcpmsg + * structure, and destroy_disp() frees the tcpmsg, so we must + * free the event *before* calling destroy_disp(). + */ + isc_event_free(&ev_in); + + disp->shutting_down = 1; + disp->shutdown_why = tcpmsg->result; + + /* + * If the recv() was canceled pass the word on. + */ + killit = destroy_disp_ok(disp); + UNLOCK(&disp->lock); + if (killit) + isc_task_send(disp->task, &disp->ctlevent); + return; + } + + dispatch_log(disp, LVL(90), "result %d, length == %d, addr = %p", + tcpmsg->result, + tcpmsg->buffer.length, tcpmsg->buffer.base); + + /* + * Peek into the buffer to see what we can see. + */ + dres = dns_message_peekheader(&tcpmsg->buffer, &id, &flags); + if (dres != ISC_R_SUCCESS) { + dispatch_log(disp, LVL(10), "got garbage packet"); + goto restart; + } + + dispatch_log(disp, LVL(92), + "got valid DNS message header, /QR %c, id %u", + ((flags & DNS_MESSAGEFLAG_QR) ? '1' : '0'), id); + + /* + * Allocate an event to send to the query or response client, and + * allocate a new buffer for our use. + */ + + /* + * Look at flags. If query, drop it. If response, + * look to see where it goes. + */ + queue_response = ISC_FALSE; + if ((flags & DNS_MESSAGEFLAG_QR) == 0) { + /* + * Query. + */ + goto restart; + } + + dns_dispatch_hash(tcpmsg->buffer.base, tcpmsg->buffer.length); + + /* + * Response. + */ + bucket = dns_hash(qid, &tcpmsg->address, id); + LOCK(&qid->lock); + resp = bucket_search(qid, &tcpmsg->address, id, bucket); + dispatch_log(disp, LVL(90), + "search for response in bucket %d: %s", + bucket, (resp == NULL ? "not found" : "found")); + + if (resp == NULL) + goto unlock; + queue_response = resp->item_out; + rev = allocate_event(disp); + if (rev == NULL) + goto unlock; + + /* + * At this point, rev contains the event we want to fill in, and + * resp contains the information on the place to send it to. + * Send the event off. + */ + dns_tcpmsg_keepbuffer(tcpmsg, &rev->buffer); + disp->tcpbuffers++; + rev->result = ISC_R_SUCCESS; + rev->id = id; + rev->addr = tcpmsg->address; + if (queue_response) { + ISC_LIST_APPEND(resp->items, rev, ev_link); + } else { + ISC_EVENT_INIT(rev, sizeof(*rev), 0, NULL, DNS_EVENT_DISPATCH, + resp->action, resp->arg, resp, NULL, NULL); + request_log(disp, resp, LVL(90), + "[b] Sent event %p buffer %p len %d to task %p", + rev, rev->buffer.base, rev->buffer.length, + resp->task); + resp->item_out = ISC_TRUE; + isc_task_send(resp->task, ISC_EVENT_PTR(&rev)); + } + unlock: + UNLOCK(&qid->lock); + + /* + * Restart recv() to get the next packet. + */ + restart: + startrecv(disp); + + UNLOCK(&disp->lock); + + isc_event_free(&ev_in); +} + +/* + * disp must be locked. + */ +static void +startrecv(dns_dispatch_t *disp) { + isc_result_t res; + isc_region_t region; + + if (disp->shutting_down == 1) + return; + + if ((disp->attributes & DNS_DISPATCHATTR_NOLISTEN) != 0) + return; + + if (disp->recv_pending != 0) + return; + + if (disp->mgr->buffers >= disp->mgr->maxbuffers) + return; + + switch (disp->socktype) { + /* + * UDP reads are always maximal. + */ + case isc_sockettype_udp: + region.length = disp->mgr->buffersize; + region.base = allocate_udp_buffer(disp); + if (region.base == NULL) + return; + res = isc_socket_recv(disp->socket, ®ion, 1, + disp->task, udp_recv, disp); + if (res != ISC_R_SUCCESS) { + free_buffer(disp, region.base, region.length); + disp->shutdown_why = res; + disp->shutting_down = 1; + do_cancel(disp); + return; + } + INSIST(disp->recv_pending == 0); + disp->recv_pending = 1; + break; + + case isc_sockettype_tcp: + res = dns_tcpmsg_readmessage(&disp->tcpmsg, disp->task, + tcp_recv, disp); + if (res != ISC_R_SUCCESS) { + disp->shutdown_why = res; + disp->shutting_down = 1; + do_cancel(disp); + return; + } + INSIST(disp->recv_pending == 0); + disp->recv_pending = 1; + break; + default: + INSIST(0); + break; + } +} + +/* + * Mgr must be locked when calling this function. + */ +static isc_boolean_t +destroy_mgr_ok(dns_dispatchmgr_t *mgr) { + mgr_log(mgr, LVL(90), + "destroy_mgr_ok: shuttingdown=%d, listnonempty=%d, " + "epool=%d, rpool=%d, dpool=%d", + MGR_IS_SHUTTINGDOWN(mgr), !ISC_LIST_EMPTY(mgr->list), + isc_mempool_getallocated(mgr->epool), + isc_mempool_getallocated(mgr->rpool), + isc_mempool_getallocated(mgr->dpool)); + if (!MGR_IS_SHUTTINGDOWN(mgr)) + return (ISC_FALSE); + if (!ISC_LIST_EMPTY(mgr->list)) + return (ISC_FALSE); + if (isc_mempool_getallocated(mgr->epool) != 0) + return (ISC_FALSE); + if (isc_mempool_getallocated(mgr->rpool) != 0) + return (ISC_FALSE); + if (isc_mempool_getallocated(mgr->dpool) != 0) + return (ISC_FALSE); + + return (ISC_TRUE); +} + +/* + * Mgr must be unlocked when calling this function. + */ +static void +destroy_mgr(dns_dispatchmgr_t **mgrp) { + isc_mem_t *mctx; + dns_dispatchmgr_t *mgr; + + mgr = *mgrp; + *mgrp = NULL; + + mctx = mgr->mctx; + + mgr->magic = 0; + mgr->mctx = NULL; + DESTROYLOCK(&mgr->lock); + mgr->state = 0; + + isc_mempool_destroy(&mgr->epool); + isc_mempool_destroy(&mgr->rpool); + isc_mempool_destroy(&mgr->dpool); + isc_mempool_destroy(&mgr->bpool); + + DESTROYLOCK(&mgr->pool_lock); + + if (mgr->entropy != NULL) + isc_entropy_detach(&mgr->entropy); + if (mgr->qid != NULL) + qid_destroy(mctx, &mgr->qid); + + DESTROYLOCK(&mgr->buffer_lock); + + if (mgr->blackhole != NULL) + dns_acl_detach(&mgr->blackhole); + + if (mgr->portlist != NULL) + dns_portlist_detach(&mgr->portlist); + + isc_mem_put(mctx, mgr, sizeof(dns_dispatchmgr_t)); + isc_mem_detach(&mctx); +} + +static isc_result_t +create_socket(isc_socketmgr_t *mgr, isc_sockaddr_t *local, + isc_socket_t **sockp) +{ + isc_socket_t *sock; + isc_result_t result; + + sock = NULL; + result = isc_socket_create(mgr, isc_sockaddr_pf(local), + isc_sockettype_udp, &sock); + if (result != ISC_R_SUCCESS) + return (result); + +#ifndef ISC_ALLOW_MAPPED + isc_socket_ipv6only(sock, ISC_TRUE); +#endif + result = isc_socket_bind(sock, local); + if (result != ISC_R_SUCCESS) { + isc_socket_detach(&sock); + return (result); + } + + *sockp = sock; + return (ISC_R_SUCCESS); +} + +/* + * Publics. + */ + +isc_result_t +dns_dispatchmgr_create(isc_mem_t *mctx, isc_entropy_t *entropy, + dns_dispatchmgr_t **mgrp) +{ + dns_dispatchmgr_t *mgr; + isc_result_t result; + + REQUIRE(mctx != NULL); + REQUIRE(mgrp != NULL && *mgrp == NULL); + + mgr = isc_mem_get(mctx, sizeof(dns_dispatchmgr_t)); + if (mgr == NULL) + return (ISC_R_NOMEMORY); + + mgr->mctx = NULL; + isc_mem_attach(mctx, &mgr->mctx); + + mgr->blackhole = NULL; + mgr->portlist = NULL; + + result = isc_mutex_init(&mgr->lock); + if (result != ISC_R_SUCCESS) + goto deallocate; + + result = isc_mutex_init(&mgr->buffer_lock); + if (result != ISC_R_SUCCESS) + goto kill_lock; + + result = isc_mutex_init(&mgr->pool_lock); + if (result != ISC_R_SUCCESS) + goto kill_buffer_lock; + + mgr->epool = NULL; + if (isc_mempool_create(mgr->mctx, sizeof(dns_dispatchevent_t), + &mgr->epool) != ISC_R_SUCCESS) { + result = ISC_R_NOMEMORY; + goto kill_pool_lock; + } + + mgr->rpool = NULL; + if (isc_mempool_create(mgr->mctx, sizeof(dns_dispentry_t), + &mgr->rpool) != ISC_R_SUCCESS) { + result = ISC_R_NOMEMORY; + goto kill_epool; + } + + mgr->dpool = NULL; + if (isc_mempool_create(mgr->mctx, sizeof(dns_dispatch_t), + &mgr->dpool) != ISC_R_SUCCESS) { + result = ISC_R_NOMEMORY; + goto kill_rpool; + } + + isc_mempool_setname(mgr->epool, "dispmgr_epool"); + isc_mempool_setfreemax(mgr->epool, 1024); + isc_mempool_associatelock(mgr->epool, &mgr->pool_lock); + + isc_mempool_setname(mgr->rpool, "dispmgr_rpool"); + isc_mempool_setfreemax(mgr->rpool, 1024); + isc_mempool_associatelock(mgr->rpool, &mgr->pool_lock); + + isc_mempool_setname(mgr->dpool, "dispmgr_dpool"); + isc_mempool_setfreemax(mgr->dpool, 1024); + isc_mempool_associatelock(mgr->dpool, &mgr->pool_lock); + + mgr->buffers = 0; + mgr->buffersize = 0; + mgr->maxbuffers = 0; + mgr->bpool = NULL; + mgr->entropy = NULL; + mgr->qid = NULL; + mgr->state = 0; + ISC_LIST_INIT(mgr->list); + mgr->magic = DNS_DISPATCHMGR_MAGIC; + + if (entropy != NULL) + isc_entropy_attach(entropy, &mgr->entropy); + + *mgrp = mgr; + return (ISC_R_SUCCESS); + + kill_rpool: + isc_mempool_destroy(&mgr->rpool); + kill_epool: + isc_mempool_destroy(&mgr->epool); + kill_pool_lock: + DESTROYLOCK(&mgr->pool_lock); + kill_buffer_lock: + DESTROYLOCK(&mgr->buffer_lock); + kill_lock: + DESTROYLOCK(&mgr->lock); + deallocate: + isc_mem_put(mctx, mgr, sizeof(dns_dispatchmgr_t)); + isc_mem_detach(&mctx); + + return (result); +} + +void +dns_dispatchmgr_setblackhole(dns_dispatchmgr_t *mgr, dns_acl_t *blackhole) { + REQUIRE(VALID_DISPATCHMGR(mgr)); + if (mgr->blackhole != NULL) + dns_acl_detach(&mgr->blackhole); + dns_acl_attach(blackhole, &mgr->blackhole); +} + +dns_acl_t * +dns_dispatchmgr_getblackhole(dns_dispatchmgr_t *mgr) { + REQUIRE(VALID_DISPATCHMGR(mgr)); + return (mgr->blackhole); +} + +void +dns_dispatchmgr_setblackportlist(dns_dispatchmgr_t *mgr, + dns_portlist_t *portlist) +{ + REQUIRE(VALID_DISPATCHMGR(mgr)); + if (mgr->portlist != NULL) + dns_portlist_detach(&mgr->portlist); + if (portlist != NULL) + dns_portlist_attach(portlist, &mgr->portlist); +} + +dns_portlist_t * +dns_dispatchmgr_getblackportlist(dns_dispatchmgr_t *mgr) { + REQUIRE(VALID_DISPATCHMGR(mgr)); + return (mgr->portlist); +} + +static isc_result_t +dns_dispatchmgr_setudp(dns_dispatchmgr_t *mgr, + unsigned int buffersize, unsigned int maxbuffers, + unsigned int buckets, unsigned int increment) +{ + isc_result_t result; + + REQUIRE(VALID_DISPATCHMGR(mgr)); + REQUIRE(buffersize >= 512 && buffersize < (64 * 1024)); + REQUIRE(maxbuffers > 0); + REQUIRE(buckets < 2097169); /* next prime > 65536 * 32 */ + REQUIRE(increment > buckets); + + /* + * Keep some number of items around. This should be a config + * option. For now, keep 8, but later keep at least two even + * if the caller wants less. This allows us to ensure certain + * things, like an event can be "freed" and the next allocation + * will always succeed. + * + * Note that if limits are placed on anything here, we use one + * event internally, so the actual limit should be "wanted + 1." + * + * XXXMLG + */ + + if (maxbuffers < 8) + maxbuffers = 8; + + LOCK(&mgr->buffer_lock); + if (mgr->bpool != NULL) { + isc_mempool_setmaxalloc(mgr->bpool, maxbuffers); + mgr->maxbuffers = maxbuffers; + UNLOCK(&mgr->buffer_lock); + return (ISC_R_SUCCESS); + } + + if (isc_mempool_create(mgr->mctx, buffersize, + &mgr->bpool) != ISC_R_SUCCESS) { + UNLOCK(&mgr->buffer_lock); + return (ISC_R_NOMEMORY); + } + + isc_mempool_setname(mgr->bpool, "dispmgr_bpool"); + isc_mempool_setmaxalloc(mgr->bpool, maxbuffers); + isc_mempool_associatelock(mgr->bpool, &mgr->pool_lock); + + result = qid_allocate(mgr, buckets, increment, ISC_TRUE, &mgr->qid); + if (result != ISC_R_SUCCESS) + goto cleanup; + + mgr->buffersize = buffersize; + mgr->maxbuffers = maxbuffers; + UNLOCK(&mgr->buffer_lock); + return (ISC_R_SUCCESS); + + cleanup: + isc_mempool_destroy(&mgr->bpool); + UNLOCK(&mgr->buffer_lock); + return (ISC_R_NOMEMORY); +} + +void +dns_dispatchmgr_destroy(dns_dispatchmgr_t **mgrp) { + dns_dispatchmgr_t *mgr; + isc_boolean_t killit; + + REQUIRE(mgrp != NULL); + REQUIRE(VALID_DISPATCHMGR(*mgrp)); + + mgr = *mgrp; + *mgrp = NULL; + + LOCK(&mgr->lock); + mgr->state |= MGR_SHUTTINGDOWN; + + killit = destroy_mgr_ok(mgr); + UNLOCK(&mgr->lock); + + mgr_log(mgr, LVL(90), "destroy: killit=%d", killit); + + if (killit) + destroy_mgr(&mgr); +} + +static isc_boolean_t +blacklisted(dns_dispatchmgr_t *mgr, isc_socket_t *sock) { + isc_sockaddr_t sockaddr; + isc_result_t result; + + if (mgr->portlist == NULL) + return (ISC_FALSE); + + result = isc_socket_getsockname(sock, &sockaddr); + if (result != ISC_R_SUCCESS) + return (ISC_FALSE); + + if (mgr->portlist != NULL && + dns_portlist_match(mgr->portlist, isc_sockaddr_pf(&sockaddr), + isc_sockaddr_getport(&sockaddr))) + return (ISC_TRUE); + return (ISC_FALSE); +} + +#define ATTRMATCH(_a1, _a2, _mask) (((_a1) & (_mask)) == ((_a2) & (_mask))) + +static isc_boolean_t +local_addr_match(dns_dispatch_t *disp, isc_sockaddr_t *addr) { + isc_sockaddr_t sockaddr; + isc_result_t result; + + if (addr == NULL) + return (ISC_TRUE); + + /* + * Don't match wildcard ports against newly blacklisted ports. + */ + if (disp->mgr->portlist != NULL && + isc_sockaddr_getport(addr) == 0 && + isc_sockaddr_getport(&disp->local) == 0 && + blacklisted(disp->mgr, disp->socket)) + return (ISC_FALSE); + + /* + * Check if we match the binding <address,port>. + * Wildcard ports match/fail here. + */ + if (isc_sockaddr_equal(&disp->local, addr)) + return (ISC_TRUE); + if (isc_sockaddr_getport(addr) == 0) + return (ISC_FALSE); + + /* + * Check if we match a bound wildcard port <address,port>. + */ + if (!isc_sockaddr_eqaddr(&disp->local, addr)) + return (ISC_FALSE); + result = isc_socket_getsockname(disp->socket, &sockaddr); + if (result != ISC_R_SUCCESS) + return (ISC_FALSE); + + return (isc_sockaddr_equal(&sockaddr, addr)); +} + +/* + * Requires mgr be locked. + * + * No dispatcher can be locked by this thread when calling this function. + * + * + * NOTE: + * If a matching dispatcher is found, it is locked after this function + * returns, and must be unlocked by the caller. + */ +static isc_result_t +dispatch_find(dns_dispatchmgr_t *mgr, isc_sockaddr_t *local, + unsigned int attributes, unsigned int mask, + dns_dispatch_t **dispp) +{ + dns_dispatch_t *disp; + isc_result_t result; + + /* + * Make certain that we will not match a private dispatch. + */ + attributes &= ~DNS_DISPATCHATTR_PRIVATE; + mask |= DNS_DISPATCHATTR_PRIVATE; + + disp = ISC_LIST_HEAD(mgr->list); + while (disp != NULL) { + LOCK(&disp->lock); + if ((disp->shutting_down == 0) + && ATTRMATCH(disp->attributes, attributes, mask) + && local_addr_match(disp, local)) + break; + UNLOCK(&disp->lock); + disp = ISC_LIST_NEXT(disp, link); + } + + if (disp == NULL) { + result = ISC_R_NOTFOUND; + goto out; + } + + *dispp = disp; + result = ISC_R_SUCCESS; + out: + + return (result); +} + +static isc_result_t +qid_allocate(dns_dispatchmgr_t *mgr, unsigned int buckets, + unsigned int increment, isc_boolean_t usepool, dns_qid_t **qidp) +{ + dns_qid_t *qid; + unsigned int i; + isc_result_t result; + + REQUIRE(VALID_DISPATCHMGR(mgr)); + REQUIRE(buckets < 2097169); /* next prime > 65536 * 32 */ + REQUIRE(increment > buckets); + REQUIRE(qidp != NULL && *qidp == NULL); + + qid = isc_mem_get(mgr->mctx, sizeof(*qid)); + if (qid == NULL) + return (ISC_R_NOMEMORY); + + qid->qid_table = isc_mem_get(mgr->mctx, + buckets * sizeof(dns_displist_t)); + if (qid->qid_table == NULL) { + isc_mem_put(mgr->mctx, qid, sizeof(*qid)); + return (ISC_R_NOMEMORY); + } + + result = nsid_init(mgr->mctx, &qid->nsid, usepool); + if (result != ISC_R_SUCCESS) { + isc_mem_put(mgr->mctx, qid->qid_table, + buckets * sizeof(dns_displist_t)); + isc_mem_put(mgr->mctx, qid, sizeof(*qid)); + return (ISC_R_NOMEMORY); + } + + result = isc_mutex_init(&qid->lock); + if (result != ISC_R_SUCCESS) { + nsid_destroy(mgr->mctx, &qid->nsid); + isc_mem_put(mgr->mctx, qid->qid_table, + buckets * sizeof(dns_displist_t)); + isc_mem_put(mgr->mctx, qid, sizeof(*qid)); + return (result); + } + + for (i = 0; i < buckets; i++) + ISC_LIST_INIT(qid->qid_table[i]); + + qid->qid_nbuckets = buckets; + qid->qid_increment = increment; + qid->magic = QID_MAGIC; + *qidp = qid; + return (ISC_R_SUCCESS); +} + +static void +qid_destroy(isc_mem_t *mctx, dns_qid_t **qidp) { + dns_qid_t *qid; + + REQUIRE(qidp != NULL); + qid = *qidp; + + REQUIRE(VALID_QID(qid)); + + *qidp = NULL; + qid->magic = 0; + nsid_destroy(mctx, &qid->nsid); + isc_mem_put(mctx, qid->qid_table, + qid->qid_nbuckets * sizeof(dns_displist_t)); + DESTROYLOCK(&qid->lock); + isc_mem_put(mctx, qid, sizeof(*qid)); +} + +/* + * Allocate and set important limits. + */ +static isc_result_t +dispatch_allocate(dns_dispatchmgr_t *mgr, unsigned int maxrequests, + dns_dispatch_t **dispp) +{ + dns_dispatch_t *disp; + isc_result_t result; + + REQUIRE(VALID_DISPATCHMGR(mgr)); + REQUIRE(dispp != NULL && *dispp == NULL); + + /* + * Set up the dispatcher, mostly. Don't bother setting some of + * the options that are controlled by tcp vs. udp, etc. + */ + + disp = isc_mempool_get(mgr->dpool); + if (disp == NULL) + return (ISC_R_NOMEMORY); + + disp->magic = 0; + disp->mgr = mgr; + disp->maxrequests = maxrequests; + disp->attributes = 0; + ISC_LINK_INIT(disp, link); + disp->refcount = 1; + disp->recv_pending = 0; + memset(&disp->local, 0, sizeof(disp->local)); + disp->shutting_down = 0; + disp->shutdown_out = 0; + disp->connected = 0; + disp->tcpmsg_valid = 0; + disp->shutdown_why = ISC_R_UNEXPECTED; + disp->requests = 0; + disp->tcpbuffers = 0; + disp->qid = NULL; + + result = isc_mutex_init(&disp->lock); + if (result != ISC_R_SUCCESS) + goto deallocate; + + disp->failsafe_ev = allocate_event(disp); + if (disp->failsafe_ev == NULL) { + result = ISC_R_NOMEMORY; + goto kill_lock; + } + + disp->magic = DISPATCH_MAGIC; + + *dispp = disp; + return (ISC_R_SUCCESS); + + /* + * error returns + */ + kill_lock: + DESTROYLOCK(&disp->lock); + deallocate: + isc_mempool_put(mgr->dpool, disp); + + return (result); +} + + +/* + * MUST be unlocked, and not used by anthing. + */ +static void +dispatch_free(dns_dispatch_t **dispp) +{ + dns_dispatch_t *disp; + dns_dispatchmgr_t *mgr; + + REQUIRE(VALID_DISPATCH(*dispp)); + disp = *dispp; + *dispp = NULL; + + mgr = disp->mgr; + REQUIRE(VALID_DISPATCHMGR(mgr)); + + if (disp->tcpmsg_valid) { + dns_tcpmsg_invalidate(&disp->tcpmsg); + disp->tcpmsg_valid = 0; + } + + INSIST(disp->tcpbuffers == 0); + INSIST(disp->requests == 0); + INSIST(disp->recv_pending == 0); + + isc_mempool_put(mgr->epool, disp->failsafe_ev); + disp->failsafe_ev = NULL; + + if (disp->qid != NULL) + qid_destroy(mgr->mctx, &disp->qid); + disp->mgr = NULL; + DESTROYLOCK(&disp->lock); + disp->magic = 0; + isc_mempool_put(mgr->dpool, disp); +} + +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 result; + dns_dispatch_t *disp; + + UNUSED(maxbuffers); + UNUSED(buffersize); + + REQUIRE(VALID_DISPATCHMGR(mgr)); + REQUIRE(isc_socket_gettype(sock) == isc_sockettype_tcp); + REQUIRE((attributes & DNS_DISPATCHATTR_TCP) != 0); + REQUIRE((attributes & DNS_DISPATCHATTR_UDP) == 0); + + attributes |= DNS_DISPATCHATTR_PRIVATE; /* XXXMLG */ + + LOCK(&mgr->lock); + + /* + * dispatch_allocate() checks mgr for us. + * qid_allocate() checks buckets and increment for us. + */ + disp = NULL; + result = dispatch_allocate(mgr, maxrequests, &disp); + if (result != ISC_R_SUCCESS) { + UNLOCK(&mgr->lock); + return (result); + } + + result = qid_allocate(mgr, buckets, increment, ISC_FALSE, &disp->qid); + if (result != ISC_R_SUCCESS) + goto deallocate_dispatch; + + disp->socktype = isc_sockettype_tcp; + disp->socket = NULL; + isc_socket_attach(sock, &disp->socket); + + disp->task = NULL; + result = isc_task_create(taskmgr, 0, &disp->task); + if (result != ISC_R_SUCCESS) + goto kill_socket; + + disp->ctlevent = isc_event_allocate(mgr->mctx, disp, + DNS_EVENT_DISPATCHCONTROL, + destroy_disp, disp, + sizeof(isc_event_t)); + if (disp->ctlevent == NULL) { + result = ISC_R_NOMEMORY; + goto kill_task; + } + + isc_task_setname(disp->task, "tcpdispatch", disp); + + dns_tcpmsg_init(mgr->mctx, disp->socket, &disp->tcpmsg); + disp->tcpmsg_valid = 1; + + disp->attributes = attributes; + + /* + * Append it to the dispatcher list. + */ + ISC_LIST_APPEND(mgr->list, disp, link); + UNLOCK(&mgr->lock); + + mgr_log(mgr, LVL(90), "created TCP dispatcher %p", disp); + dispatch_log(disp, LVL(90), "created task %p", disp->task); + + *dispp = disp; + + return (ISC_R_SUCCESS); + + /* + * Error returns. + */ + kill_task: + isc_task_detach(&disp->task); + kill_socket: + isc_socket_detach(&disp->socket); + deallocate_dispatch: + dispatch_free(&disp); + + UNLOCK(&mgr->lock); + + return (result); +} + +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 result; + dns_dispatch_t *disp; + + REQUIRE(VALID_DISPATCHMGR(mgr)); + REQUIRE(sockmgr != NULL); + REQUIRE(localaddr != NULL); + REQUIRE(taskmgr != NULL); + REQUIRE(buffersize >= 512 && buffersize < (64 * 1024)); + REQUIRE(maxbuffers > 0); + REQUIRE(buckets < 2097169); /* next prime > 65536 * 32 */ + REQUIRE(increment > buckets); + REQUIRE(dispp != NULL && *dispp == NULL); + REQUIRE((attributes & DNS_DISPATCHATTR_TCP) == 0); + + result = dns_dispatchmgr_setudp(mgr, buffersize, maxbuffers, + buckets, increment); + if (result != ISC_R_SUCCESS) + return (result); + + LOCK(&mgr->lock); + + /* + * First, see if we have a dispatcher that matches. + */ + disp = NULL; + result = dispatch_find(mgr, localaddr, attributes, mask, &disp); + if (result == ISC_R_SUCCESS) { + disp->refcount++; + + if (disp->maxrequests < maxrequests) + disp->maxrequests = maxrequests; + + if ((disp->attributes & DNS_DISPATCHATTR_NOLISTEN) == 0 && + (attributes & DNS_DISPATCHATTR_NOLISTEN) != 0) + { + disp->attributes |= DNS_DISPATCHATTR_NOLISTEN; + if (disp->recv_pending != 0) + isc_socket_cancel(disp->socket, disp->task, + ISC_SOCKCANCEL_RECV); + } + + UNLOCK(&disp->lock); + UNLOCK(&mgr->lock); + + *dispp = disp; + + return (ISC_R_SUCCESS); + } + + /* + * Nope, create one. + */ + result = dispatch_createudp(mgr, sockmgr, taskmgr, localaddr, + maxrequests, attributes, &disp); + if (result != ISC_R_SUCCESS) { + UNLOCK(&mgr->lock); + return (result); + } + + UNLOCK(&mgr->lock); + *dispp = disp; + return (ISC_R_SUCCESS); +} + +/* + * mgr should be locked. + */ + +#ifndef DNS_DISPATCH_HELD +#define DNS_DISPATCH_HELD 20U +#endif + +static isc_result_t +dispatch_createudp(dns_dispatchmgr_t *mgr, isc_socketmgr_t *sockmgr, + isc_taskmgr_t *taskmgr, + isc_sockaddr_t *localaddr, + unsigned int maxrequests, + unsigned int attributes, + dns_dispatch_t **dispp) +{ + isc_result_t result; + dns_dispatch_t *disp; + isc_socket_t *sock = NULL; + isc_socket_t *held[DNS_DISPATCH_HELD]; + unsigned int i = 0, j = 0; + + /* + * dispatch_allocate() checks mgr for us. + */ + disp = NULL; + result = dispatch_allocate(mgr, maxrequests, &disp); + if (result != ISC_R_SUCCESS) + return (result); + + /* + * Try to allocate a socket that is not on the blacklist. + * Hold up to DNS_DISPATCH_HELD sockets to prevent the OS + * from returning the same port to us too quickly. + */ + memset(held, 0, sizeof(held)); + getsocket: + result = create_socket(sockmgr, localaddr, &sock); + if (result != ISC_R_SUCCESS) + goto deallocate_dispatch; + if (isc_sockaddr_getport(localaddr) == 0 && blacklisted(mgr, sock)) { + if (held[i] != NULL) + isc_socket_detach(&held[i]); + held[i++] = sock; + sock = NULL; + if (i == DNS_DISPATCH_HELD) + i = 0; + if (j++ == 0xffffU) { + mgr_log(mgr, ISC_LOG_ERROR, "avoid-v%s-udp-ports: " + "unable to allocate a non-blacklisted port", + isc_sockaddr_pf(localaddr) == AF_INET ? + "4" : "6"); + result = ISC_R_FAILURE; + goto deallocate_dispatch; + } + goto getsocket; + } + + disp->socktype = isc_sockettype_udp; + disp->socket = sock; + disp->local = *localaddr; + + disp->task = NULL; + result = isc_task_create(taskmgr, 0, &disp->task); + if (result != ISC_R_SUCCESS) + goto kill_socket; + + disp->ctlevent = isc_event_allocate(mgr->mctx, disp, + DNS_EVENT_DISPATCHCONTROL, + destroy_disp, disp, + sizeof(isc_event_t)); + if (disp->ctlevent == NULL) { + result = ISC_R_NOMEMORY; + goto kill_task; + } + + isc_task_setname(disp->task, "udpdispatch", disp); + + attributes &= ~DNS_DISPATCHATTR_TCP; + attributes |= DNS_DISPATCHATTR_UDP; + disp->attributes = attributes; + + /* + * Append it to the dispatcher list. + */ + ISC_LIST_APPEND(mgr->list, disp, link); + + mgr_log(mgr, LVL(90), "created UDP dispatcher %p", disp); + dispatch_log(disp, LVL(90), "created task %p", disp->task); + dispatch_log(disp, LVL(90), "created socket %p", disp->socket); + + *dispp = disp; + + goto cleanheld; + + /* + * Error returns. + */ + kill_task: + isc_task_detach(&disp->task); + kill_socket: + isc_socket_detach(&disp->socket); + deallocate_dispatch: + dispatch_free(&disp); + cleanheld: + for (i = 0; i < DNS_DISPATCH_HELD; i++) + if (held[i] != NULL) + isc_socket_detach(&held[i]); + return (result); +} + +void +dns_dispatch_attach(dns_dispatch_t *disp, dns_dispatch_t **dispp) { + REQUIRE(VALID_DISPATCH(disp)); + REQUIRE(dispp != NULL && *dispp == NULL); + + LOCK(&disp->lock); + disp->refcount++; + UNLOCK(&disp->lock); + + *dispp = disp; +} + +/* + * It is important to lock the manager while we are deleting the dispatch, + * since dns_dispatch_getudp will call dispatch_find, which returns to + * the caller a dispatch but does not attach to it until later. _getudp + * locks the manager, however, so locking it here will keep us from attaching + * to a dispatcher that is in the process of going away. + */ +void +dns_dispatch_detach(dns_dispatch_t **dispp) { + dns_dispatch_t *disp; + isc_boolean_t killit; + + REQUIRE(dispp != NULL && VALID_DISPATCH(*dispp)); + + disp = *dispp; + *dispp = NULL; + + LOCK(&disp->lock); + + INSIST(disp->refcount > 0); + disp->refcount--; + killit = ISC_FALSE; + if (disp->refcount == 0) { + if (disp->recv_pending > 0) + isc_socket_cancel(disp->socket, disp->task, + ISC_SOCKCANCEL_RECV); + disp->shutting_down = 1; + } + + dispatch_log(disp, LVL(90), "detach: refcount %d", disp->refcount); + + killit = destroy_disp_ok(disp); + UNLOCK(&disp->lock); + if (killit) + isc_task_send(disp->task, &disp->ctlevent); +} + +isc_result_t +dns_dispatch_addresponse(dns_dispatch_t *disp, isc_sockaddr_t *dest, + isc_task_t *task, isc_taskaction_t action, void *arg, + dns_messageid_t *idp, dns_dispentry_t **resp) +{ + dns_dispentry_t *res; + unsigned int bucket; + dns_messageid_t id; + int i; + isc_boolean_t ok; + dns_qid_t *qid; + + REQUIRE(VALID_DISPATCH(disp)); + REQUIRE(task != NULL); + REQUIRE(dest != NULL); + REQUIRE(resp != NULL && *resp == NULL); + REQUIRE(idp != NULL); + + LOCK(&disp->lock); + + if (disp->shutting_down == 1) { + UNLOCK(&disp->lock); + return (ISC_R_SHUTTINGDOWN); + } + + if (disp->requests >= disp->maxrequests) { + UNLOCK(&disp->lock); + return (ISC_R_QUOTA); + } + + /* + * Try somewhat hard to find an unique ID. + */ + qid = DNS_QID(disp); + LOCK(&qid->lock); + id = dns_randomid(&qid->nsid); + bucket = dns_hash(qid, dest, id); + ok = ISC_FALSE; + for (i = 0; i < 64; i++) { + if (bucket_search(qid, dest, id, bucket) == NULL) { + ok = ISC_TRUE; + break; + } + id += qid->qid_increment; + id &= 0x0000ffff; + bucket = dns_hash(qid, dest, id); + } + + if (!ok) { + UNLOCK(&qid->lock); + UNLOCK(&disp->lock); + return (ISC_R_NOMORE); + } + + res = isc_mempool_get(disp->mgr->rpool); + if (res == NULL) { + UNLOCK(&qid->lock); + UNLOCK(&disp->lock); + return (ISC_R_NOMEMORY); + } + + disp->refcount++; + disp->requests++; + res->task = NULL; + isc_task_attach(task, &res->task); + res->disp = disp; + res->id = id; + res->bucket = bucket; + res->host = *dest; + res->action = action; + res->arg = arg; + res->item_out = ISC_FALSE; + ISC_LIST_INIT(res->items); + ISC_LINK_INIT(res, link); + res->magic = RESPONSE_MAGIC; + ISC_LIST_APPEND(qid->qid_table[bucket], res, link); + UNLOCK(&qid->lock); + + request_log(disp, res, LVL(90), + "attached to task %p", res->task); + + if (((disp->attributes & DNS_DISPATCHATTR_UDP) != 0) || + ((disp->attributes & DNS_DISPATCHATTR_CONNECTED) != 0)) + startrecv(disp); + + UNLOCK(&disp->lock); + + *idp = id; + *resp = res; + + return (ISC_R_SUCCESS); +} + +void +dns_dispatch_starttcp(dns_dispatch_t *disp) { + + REQUIRE(VALID_DISPATCH(disp)); + + dispatch_log(disp, LVL(90), "starttcp %p", disp->task); + + LOCK(&disp->lock); + disp->attributes |= DNS_DISPATCHATTR_CONNECTED; + startrecv(disp); + UNLOCK(&disp->lock); +} + +void +dns_dispatch_removeresponse(dns_dispentry_t **resp, + dns_dispatchevent_t **sockevent) +{ + dns_dispatchmgr_t *mgr; + dns_dispatch_t *disp; + dns_dispentry_t *res; + dns_dispatchevent_t *ev; + unsigned int bucket; + isc_boolean_t killit; + unsigned int n; + isc_eventlist_t events; + dns_qid_t *qid; + + REQUIRE(resp != NULL); + REQUIRE(VALID_RESPONSE(*resp)); + + res = *resp; + *resp = NULL; + + disp = res->disp; + REQUIRE(VALID_DISPATCH(disp)); + mgr = disp->mgr; + REQUIRE(VALID_DISPATCHMGR(mgr)); + + qid = DNS_QID(disp); + + if (sockevent != NULL) { + REQUIRE(*sockevent != NULL); + ev = *sockevent; + *sockevent = NULL; + } else { + ev = NULL; + } + + LOCK(&disp->lock); + + INSIST(disp->requests > 0); + disp->requests--; + INSIST(disp->refcount > 0); + disp->refcount--; + killit = ISC_FALSE; + if (disp->refcount == 0) { + if (disp->recv_pending > 0) + isc_socket_cancel(disp->socket, disp->task, + ISC_SOCKCANCEL_RECV); + disp->shutting_down = 1; + } + + bucket = res->bucket; + + LOCK(&qid->lock); + ISC_LIST_UNLINK(qid->qid_table[bucket], res, link); + UNLOCK(&qid->lock); + + if (ev == NULL && res->item_out) { + /* + * We've posted our event, but the caller hasn't gotten it + * yet. Take it back. + */ + ISC_LIST_INIT(events); + n = isc_task_unsend(res->task, res, DNS_EVENT_DISPATCH, + NULL, &events); + /* + * We had better have gotten it back. + */ + INSIST(n == 1); + ev = (dns_dispatchevent_t *)ISC_LIST_HEAD(events); + } + + if (ev != NULL) { + REQUIRE(res->item_out == ISC_TRUE); + res->item_out = ISC_FALSE; + if (ev->buffer.base != NULL) + free_buffer(disp, ev->buffer.base, ev->buffer.length); + free_event(disp, ev); + } + + request_log(disp, res, LVL(90), "detaching from task %p", res->task); + isc_task_detach(&res->task); + + /* + * Free any buffered requests as well + */ + ev = ISC_LIST_HEAD(res->items); + while (ev != NULL) { + ISC_LIST_UNLINK(res->items, ev, ev_link); + if (ev->buffer.base != NULL) + free_buffer(disp, ev->buffer.base, ev->buffer.length); + free_event(disp, ev); + ev = ISC_LIST_HEAD(res->items); + } + res->magic = 0; + isc_mempool_put(disp->mgr->rpool, res); + if (disp->shutting_down == 1) + do_cancel(disp); + else + startrecv(disp); + + killit = destroy_disp_ok(disp); + UNLOCK(&disp->lock); + if (killit) + isc_task_send(disp->task, &disp->ctlevent); +} + +static void +do_cancel(dns_dispatch_t *disp) { + dns_dispatchevent_t *ev; + dns_dispentry_t *resp; + dns_qid_t *qid; + + if (disp->shutdown_out == 1) + return; + + qid = DNS_QID(disp); + + /* + * Search for the first response handler without packets outstanding. + */ + LOCK(&qid->lock); + for (resp = linear_first(qid); + resp != NULL && resp->item_out != ISC_FALSE; + /* Empty. */) + resp = linear_next(qid, resp); + /* + * No one to send the cancel event to, so nothing to do. + */ + if (resp == NULL) + goto unlock; + + /* + * Send the shutdown failsafe event to this resp. + */ + ev = disp->failsafe_ev; + ISC_EVENT_INIT(ev, sizeof(*ev), 0, NULL, DNS_EVENT_DISPATCH, + resp->action, resp->arg, resp, NULL, NULL); + ev->result = disp->shutdown_why; + ev->buffer.base = NULL; + ev->buffer.length = 0; + disp->shutdown_out = 1; + request_log(disp, resp, LVL(10), + "cancel: failsafe event %p -> task %p", + ev, resp->task); + resp->item_out = ISC_TRUE; + isc_task_send(resp->task, ISC_EVENT_PTR(&ev)); + unlock: + UNLOCK(&qid->lock); +} + +isc_socket_t * +dns_dispatch_getsocket(dns_dispatch_t *disp) { + REQUIRE(VALID_DISPATCH(disp)); + + return (disp->socket); +} + +isc_result_t +dns_dispatch_getlocaladdress(dns_dispatch_t *disp, isc_sockaddr_t *addrp) { + + REQUIRE(VALID_DISPATCH(disp)); + REQUIRE(addrp != NULL); + + if (disp->socktype == isc_sockettype_udp) { + *addrp = disp->local; + return (ISC_R_SUCCESS); + } + return (ISC_R_NOTIMPLEMENTED); +} + +void +dns_dispatch_cancel(dns_dispatch_t *disp) { + REQUIRE(VALID_DISPATCH(disp)); + + LOCK(&disp->lock); + + if (disp->shutting_down == 1) { + UNLOCK(&disp->lock); + return; + } + + disp->shutdown_why = ISC_R_CANCELED; + disp->shutting_down = 1; + do_cancel(disp); + + UNLOCK(&disp->lock); + + return; +} + +void +dns_dispatch_changeattributes(dns_dispatch_t *disp, + unsigned int attributes, unsigned int mask) +{ + REQUIRE(VALID_DISPATCH(disp)); + + /* XXXMLG + * Should check for valid attributes here! + */ + + LOCK(&disp->lock); + + if ((mask & DNS_DISPATCHATTR_NOLISTEN) != 0) { + if ((disp->attributes & DNS_DISPATCHATTR_NOLISTEN) != 0 && + (attributes & DNS_DISPATCHATTR_NOLISTEN) == 0) { + disp->attributes &= ~DNS_DISPATCHATTR_NOLISTEN; + startrecv(disp); + } else if ((disp->attributes & DNS_DISPATCHATTR_NOLISTEN) + == 0 && + (attributes & DNS_DISPATCHATTR_NOLISTEN) != 0) { + disp->attributes |= DNS_DISPATCHATTR_NOLISTEN; + if (disp->recv_pending != 0) + isc_socket_cancel(disp->socket, disp->task, + ISC_SOCKCANCEL_RECV); + } + } + + disp->attributes &= ~mask; + disp->attributes |= (attributes & mask); + UNLOCK(&disp->lock); +} + +void +dns_dispatch_importrecv(dns_dispatch_t *disp, isc_event_t *event) { + void *buf; + isc_socketevent_t *sevent, *newsevent; + + REQUIRE(VALID_DISPATCH(disp)); + REQUIRE((disp->attributes & DNS_DISPATCHATTR_NOLISTEN) != 0); + REQUIRE(event != NULL); + + sevent = (isc_socketevent_t *)event; + + INSIST(sevent->n <= disp->mgr->buffersize); + newsevent = (isc_socketevent_t *) + isc_event_allocate(disp->mgr->mctx, NULL, + DNS_EVENT_IMPORTRECVDONE, udp_recv, + disp, sizeof(isc_socketevent_t)); + if (newsevent == NULL) + return; + + buf = allocate_udp_buffer(disp); + if (buf == NULL) { + isc_event_free(ISC_EVENT_PTR(&newsevent)); + return; + } + memcpy(buf, sevent->region.base, sevent->n); + newsevent->region.base = buf; + newsevent->region.length = disp->mgr->buffersize; + newsevent->n = sevent->n; + newsevent->result = sevent->result; + newsevent->address = sevent->address; + newsevent->timestamp = sevent->timestamp; + newsevent->pktinfo = sevent->pktinfo; + newsevent->attributes = sevent->attributes; + + isc_task_send(disp->task, ISC_EVENT_PTR(&newsevent)); +} + +#if 0 +void +dns_dispatchmgr_dump(dns_dispatchmgr_t *mgr) { + dns_dispatch_t *disp; + char foo[1024]; + + disp = ISC_LIST_HEAD(mgr->list); + while (disp != NULL) { + isc_sockaddr_format(&disp->local, foo, sizeof(foo)); + printf("\tdispatch %p, addr %s\n", disp, foo); + disp = ISC_LIST_NEXT(disp, link); + } +} +#endif + +/* + * Allow the user to pick one of two ID randomization algorithms. + * + * The first algorithm is an adaptation of the sequence shuffling + * algorithm discovered by Carter Bays and S. D. Durham [ACM Trans. Math. + * Software 2 (1976), 59-64], as documented as Algorithm B in Chapter + * 3.2.2 in Volume 2 of Knuth's "The Art of Computer Programming". We use + * a randomly selected linear congruential random number generator with a + * modulus of 2^16, whose increment is a randomly picked odd number, and + * whose multiplier is picked from a set which meets the following + * criteria: + * Is of the form 8*n+5, which ensures "high potency" according to + * principle iii in the summary chapter 3.6. This form also has a + * gcd(a-1,m) of 4 which is good according to principle iv. + * + * Is between 0.01 and 0.99 times the modulus as specified by + * principle iv. + * + * Passes the spectral test "with flying colors" (ut >= 1) in + * dimensions 2 through 6 as calculated by Algorithm S in Chapter + * 3.3.4 and the ratings calculated by formula 35 in section E. + * + * Of the multipliers that pass this test, pick the set that is + * best according to the theoretical bounds of the serial + * correlation test. This was calculated using a simplified + * version of Knuth's Theorem K in Chapter 3.3.3. + * + * These criteria may not be important for this use, but we might as well + * pick from the best generators since there are so many possible ones and + * we don't have that many random bits to do the picking. + * + * We use a modulus of 2^16 instead of something bigger so that we will + * tend to cycle through all the possible IDs before repeating any, + * however the shuffling will perturb this somewhat. Theoretically there + * is no minimimum interval between two uses of the same ID, but in + * practice it seems to be >64000. + * + * Our adaptatation of Algorithm B mixes the hash state which has + * captured various random events into the shuffler to perturb the + * sequence. + * + * One disadvantage of this algorithm is that if the generator parameters + * were to be guessed, it would be possible to mount a limited brute force + * attack on the ID space since the IDs are only shuffled within a limited + * range. + * + * The second algorithm uses the same random number generator to populate + * a pool of 65536 IDs. The hash state is used to pick an ID from a window + * of 4096 IDs in this pool, then the chosen ID is swapped with the ID + * at the beginning of the window and the window position is advanced. + * This means that the interval between uses of the ID will be no less + * than 65536-4096. The ID sequence in the pool will become more random + * over time. + * + * For both algorithms, two more linear congruential random number generators + * are selected. The ID from the first part of algorithm is used to seed + * the first of these generators, and its output is used to seed the second. + * The strategy is use these generators as 1 to 1 hashes to obfuscate the + * properties of the generator used in the first part of either algorithm. + * + * The first algorithm may be suitable for use in a client resolver since + * its memory requirements are fairly low and it's pretty random out of + * the box. It is somewhat succeptible to a limited brute force attack, + * so the second algorithm is probably preferable for a longer running + * program that issues a large number of queries and has time to randomize + * the pool. + */ + +#define NSID_SHUFFLE_TABLE_SIZE 100 /* Suggested by Knuth */ +/* + * Pick one of the next 4096 IDs in the pool. + * There is a tradeoff here between randomness and how often and ID is reused. + */ +#define NSID_LOOKAHEAD 4096 /* Must be a power of 2 */ +#define NSID_SHUFFLE_ONLY 1 /* algorithm 1 */ +#define NSID_USE_POOL 2 /* algorithm 2 */ +#define NSID_HASHSHIFT 3 +#define NSID_HASHROTATE(v) \ + (((v) << NSID_HASHSHIFT) | ((v) >> ((sizeof(v) * 8) - NSID_HASHSHIFT))) + +static isc_uint32_t nsid_hash_state; + +/* + * Keep a running hash of various bits of data that we'll use to + * stir the ID pool or perturb the ID generator + */ +static void +nsid_hash(void *data, size_t len) { + unsigned char *p = data; + /* + * Hash function similar to the one we use for hashing names. + * We don't fold case or toss the upper bit here, though. + * This hash doesn't do much interesting when fed binary zeros, + * so there may be a better hash function. + * This function doesn't need to be very strong since we're + * only using it to stir the pool, but it should be reasonably + * fast. + */ + /* + * We don't care about locking access to nsid_hash_state. + * In fact races make the result even more non deteministic. + */ + while (len-- > 0U) { + nsid_hash_state = NSID_HASHROTATE(nsid_hash_state); + nsid_hash_state += *p++; + } +} + +/* + * Table of good linear congruential multipliers for modulus 2^16 + * in order of increasing serial correlation bounds (so trim from + * the end). + */ +static const isc_uint16_t nsid_multiplier_table[] = { + 17565, 25013, 11733, 19877, 23989, 23997, 24997, 25421, + 26781, 27413, 35901, 35917, 35973, 36229, 38317, 38437, + 39941, 40493, 41853, 46317, 50581, 51429, 53453, 53805, + 11317, 11789, 12045, 12413, 14277, 14821, 14917, 18989, + 19821, 23005, 23533, 23573, 23693, 27549, 27709, 28461, + 29365, 35605, 37693, 37757, 38309, 41285, 45261, 47061, + 47269, 48133, 48597, 50277, 50717, 50757, 50805, 51341, + 51413, 51581, 51597, 53445, 11493, 14229, 20365, 20653, + 23485, 25541, 27429, 29421, 30173, 35445, 35653, 36789, + 36797, 37109, 37157, 37669, 38661, 39773, 40397, 41837, + 41877, 45293, 47277, 47845, 49853, 51085, 51349, 54085, + 56933, 8877, 8973, 9885, 11365, 11813, 13581, 13589, + 13613, 14109, 14317, 15765, 15789, 16925, 17069, 17205, + 17621, 17941, 19077, 19381, 20245, 22845, 23733, 24869, + 25453, 27213, 28381, 28965, 29245, 29997, 30733, 30901, + 34877, 35485, 35613, 36133, 36661, 36917, 38597, 40285, + 40693, 41413, 41541, 41637, 42053, 42349, 45245, 45469, + 46493, 48205, 48613, 50861, 51861, 52877, 53933, 54397, + 55669, 56453, 56965, 58021, 7757, 7781, 8333, 9661, + 12229, 14373, 14453, 17549, 18141, 19085, 20773, 23701, + 24205, 24333, 25261, 25317, 27181, 30117, 30477, 34757, + 34885, 35565, 35885, 36541, 37957, 39733, 39813, 41157, + 41893, 42317, 46621, 48117, 48181, 49525, 55261, 55389, + 56845, 7045, 7749, 7965, 8469, 9133, 9549, 9789, + 10173, 11181, 11285, 12253, 13453, 13533, 13757, 14477, + 15053, 16901, 17213, 17269, 17525, 17629, 18605, 19013, + 19829, 19933, 20069, 20093, 23261, 23333, 24949, 25309, + 27613, 28453, 28709, 29301, 29541, 34165, 34413, 37301, + 37773, 38045, 38405, 41077, 41781, 41925, 42717, 44437, + 44525, 44613, 45933, 45941, 47077, 50077, 50893, 52117, + 5293, 55069, 55989, 58125, 59205, 6869, 14685, 15453, + 16821, 17045, 17613, 18437, 21029, 22773, 22909, 25445, + 25757, 26541, 30709, 30909, 31093, 31149, 37069, 37725, + 37925, 38949, 39637, 39701, 40765, 40861, 42965, 44813, + 45077, 45733, 47045, 50093, 52861, 52957, 54181, 56325, + 56365, 56381, 56877, 57013, 5741, 58101, 58669, 8613, + 10045, 10261, 10653, 10733, 11461, 12261, 14069, 15877, + 17757, 21165, 23885, 24701, 26429, 26645, 27925, 28765, + 29197, 30189, 31293, 39781, 39909, 40365, 41229, 41453, + 41653, 42165, 42365, 47421, 48029, 48085, 52773, 5573, + 57037, 57637, 58341, 58357, 58901, 6357, 7789, 9093, + 10125, 10709, 10765, 11957, 12469, 13437, 13509, 14773, + 15437, 15773, 17813, 18829, 19565, 20237, 23461, 23685, + 23725, 23941, 24877, 25461, 26405, 29509, 30285, 35181, + 37229, 37893, 38565, 40293, 44189, 44581, 45701, 47381, + 47589, 48557, 4941, 51069, 5165, 52797, 53149, 5341, + 56301, 56765, 58581, 59493, 59677, 6085, 6349, 8293, + 8501, 8517, 11597, 11709, 12589, 12693, 13517, 14909, + 17397, 18085, 21101, 21269, 22717, 25237, 25661, 29189, + 30101, 31397, 33933, 34213, 34661, 35533, 36493, 37309, + 40037, 4189, 42909, 44309, 44357, 44389, 4541, 45461, + 46445, 48237, 54149, 55301, 55853, 56621, 56717, 56901, + 5813, 58437, 12493, 15365, 15989, 17829, 18229, 19341, + 21013, 21357, 22925, 24885, 26053, 27581, 28221, 28485, + 30605, 30613, 30789, 35437, 36285, 37189, 3941, 41797, + 4269, 42901, 43293, 44645, 45221, 46893, 4893, 50301, + 50325, 5189, 52109, 53517, 54053, 54485, 5525, 55949, + 56973, 59069, 59421, 60733, 61253, 6421, 6701, 6709, + 7101, 8669, 15797, 19221, 19837, 20133, 20957, 21293, + 21461, 22461, 29085, 29861, 30869, 34973, 36469, 37565, + 38125, 38829, 39469, 40061, 40117, 44093, 47429, 48341, + 50597, 51757, 5541, 57629, 58405, 59621, 59693, 59701, + 61837, 7061, 10421, 11949, 15405, 20861, 25397, 25509, + 25893, 26037, 28629, 28869, 29605, 30213, 34205, 35637, + 36365, 37285, 3773, 39117, 4021, 41061, 42653, 44509, + 4461, 44829, 4725, 5125, 52269, 56469, 59085, 5917, + 60973, 8349, 17725, 18637, 19773, 20293, 21453, 22533, + 24285, 26333, 26997, 31501, 34541, 34805, 37509, 38477, + 41333, 44125, 46285, 46997, 47637, 48173, 4925, 50253, + 50381, 50917, 51205, 51325, 52165, 52229, 5253, 5269, + 53509, 56253, 56341, 5821, 58373, 60301, 61653, 61973, + 62373, 8397, 11981, 14341, 14509, 15077, 22261, 22429, + 24261, 28165, 28685, 30661, 34021, 34445, 39149, 3917, + 43013, 43317, 44053, 44101, 4533, 49541, 49981, 5277, + 54477, 56357, 57261, 57765, 58573, 59061, 60197, 61197, + 62189, 7725, 8477, 9565, 10229, 11437, 14613, 14709, + 16813, 20029, 20677, 31445, 3165, 31957, 3229, 33541, + 36645, 3805, 38973, 3965, 4029, 44293, 44557, 46245, + 48917, 4909, 51749, 53709, 55733, 56445, 5925, 6093, + 61053, 62637, 8661, 9109, 10821, 11389, 13813, 14325, + 15501, 16149, 18845, 22669, 26437, 29869, 31837, 33709, + 33973, 34173, 3677, 3877, 3981, 39885, 42117, 4421, + 44221, 44245, 44693, 46157, 47309, 5005, 51461, 52037, + 55333, 55693, 56277, 58949, 6205, 62141, 62469, 6293, + 10101, 12509, 14029, 17997, 20469, 21149, 25221, 27109, + 2773, 2877, 29405, 31493, 31645, 4077, 42005, 42077, + 42469, 42501, 44013, 48653, 49349, 4997, 50101, 55405, + 56957, 58037, 59429, 60749, 61797, 62381, 62837, 6605, + 10541, 23981, 24533, 2701, 27333, 27341, 31197, 33805, + 3621, 37381, 3749, 3829, 38533, 42613, 44381, 45901, + 48517, 51269, 57725, 59461, 60045, 62029, 13805, 14013, + 15461, 16069, 16157, 18573, 2309, 23501, 28645, 3077, + 31541, 36357, 36877, 3789, 39429, 39805, 47685, 47949, + 49413, 5485, 56757, 57549, 57805, 58317, 59549, 62213, + 62613, 62853, 62933, 8909, 12941, 16677, 20333, 21541, + 24429, 26077, 26421, 2885, 31269, 33381, 3661, 40925, + 42925, 45173, 4525, 4709, 53133, 55941, 57413, 57797, + 62125, 62237, 62733, 6773, 12317, 13197, 16533, 16933, + 18245, 2213, 2477, 29757, 33293, 35517, 40133, 40749, + 4661, 49941, 62757, 7853, 8149, 8573, 11029, 13421, + 21549, 22709, 22725, 24629, 2469, 26125, 2669, 34253, + 36709, 41013, 45597, 46637, 52285, 52333, 54685, 59013, + 60997, 61189, 61981, 62605, 62821, 7077, 7525, 8781, + 10861, 15277, 2205, 22077, 28517, 28949, 32109, 33493, + 4661, 49941, 62757, 7853, 8149, 8573, 11029, 13421, + 21549, 22709, 22725, 24629, 2469, 26125, 2669, 34253, + 36709, 41013, 45597, 46637, 52285, 52333, 54685, 59013, + 60997, 61189, 61981, 62605, 62821, 7077, 7525, 8781, + 10861, 15277, 2205, 22077, 28517, 28949, 32109, 33493, + 3685, 39197, 39869, 42621, 44997, 48565, 5221, 57381, + 61749, 62317, 63245, 63381, 23149, 2549, 28661, 31653, + 33885, 36341, 37053, 39517, 42805, 45853, 48997, 59349, + 60053, 62509, 63069, 6525, 1893, 20181, 2365, 24893, + 27397, 31357, 32277, 33357, 34437, 36677, 37661, 43469, + 43917, 50997, 53869, 5653, 13221, 16741, 17893, 2157, + 28653, 31789, 35301, 35821, 61613, 62245, 12405, 14517, + 17453, 18421, 3149, 3205, 40341, 4109, 43941, 46869, + 48837, 50621, 57405, 60509, 62877, 8157, 12933, 12957, + 16501, 19533, 3461, 36829, 52357, 58189, 58293, 63053, + 17109, 1933, 32157, 37701, 59005, 61621, 13029, 15085, + 16493, 32317, 35093, 5061, 51557, 62221, 20765, 24613, + 2629, 30861, 33197, 33749, 35365, 37933, 40317, 48045, + 56229, 61157, 63797, 7917, 17965, 1917, 1973, 20301, + 2253, 33157, 58629, 59861, 61085, 63909, 8141, 9221, + 14757, 1581, 21637, 26557, 33869, 34285, 35733, 40933, + 42517, 43501, 53653, 61885, 63805, 7141, 21653, 54973, + 31189, 60061, 60341, 63357, 16045, 2053, 26069, 33997, + 43901, 54565, 63837, 8949, 17909, 18693, 32349, 33125, + 37293, 48821, 49053, 51309, 64037, 7117, 1445, 20405, + 23085, 26269, 26293, 27349, 32381, 33141, 34525, 36461, + 37581, 43525, 4357, 43877, 5069, 55197, 63965, 9845, + 12093, 2197, 2229, 32165, 33469, 40981, 42397, 8749, + 10853, 1453, 18069, 21693, 30573, 36261, 37421, 42533 +}; + +#define NSID_MULT_TABLE_SIZE \ + ((sizeof nsid_multiplier_table)/(sizeof nsid_multiplier_table[0])) +#define NSID_RANGE_MASK (NSID_LOOKAHEAD - 1) +#define NSID_POOL_MASK 0xFFFF /* used to wrap the pool index */ +#define NSID_SHUFFLE_ONLY 1 +#define NSID_USE_POOL 2 + +static isc_uint16_t +nsid_next(dns_nsid_t *nsid) { + isc_uint16_t id, compressed_hash; + isc_uint16_t j; + + compressed_hash = ((nsid_hash_state >> 16) ^ + (nsid_hash_state)) & 0xFFFF; + + if (nsid->nsid_usepool) { + isc_uint16_t pick; + + pick = compressed_hash & NSID_RANGE_MASK; + pick = (nsid->nsid_state + pick) & NSID_POOL_MASK; + id = nsid->nsid_pool[pick]; + if (pick != 0) { + /* Swap two IDs to stir the pool */ + nsid->nsid_pool[pick] = + nsid->nsid_pool[nsid->nsid_state]; + nsid->nsid_pool[nsid->nsid_state] = id; + } + + /* increment the base pointer into the pool */ + if (nsid->nsid_state == 65535) + nsid->nsid_state = 0; + else + nsid->nsid_state++; + } else { + /* + * This is the original Algorithm B + * j = ((u_long) NSID_SHUFFLE_TABLE_SIZE * nsid_state2) >> 16; + * + * We'll perturb it with some random stuff ... + */ + j = ((isc_uint32_t) NSID_SHUFFLE_TABLE_SIZE * + (nsid->nsid_state2 ^ compressed_hash)) >> 16; + nsid->nsid_state2 = id = nsid->nsid_vtable[j]; + nsid->nsid_state = (((isc_uint32_t) nsid->nsid_a1 * nsid->nsid_state) + + nsid->nsid_c1) & 0xFFFF; + nsid->nsid_vtable[j] = nsid->nsid_state; + } + + /* Now lets obfuscate ... */ + id = (((isc_uint32_t) nsid->nsid_a2 * id) + nsid->nsid_c2) & 0xFFFF; + id = (((isc_uint32_t) nsid->nsid_a3 * id) + nsid->nsid_c3) & 0xFFFF; + + return (id); +} + +static isc_result_t +nsid_init(isc_mem_t *mctx, dns_nsid_t *nsid, isc_boolean_t usepool) { + isc_time_t now; + pid_t mypid; + isc_uint16_t a1ndx, a2ndx, a3ndx, c1ndx, c2ndx, c3ndx; + int i; + + isc_time_now(&now); + mypid = getpid(); + + /* Initialize the state */ + memset(nsid, 0, sizeof(*nsid)); + nsid_hash(&now, sizeof now); + nsid_hash(&mypid, sizeof mypid); + + /* + * Select our random number generators and initial seed. + * We could really use more random bits at this point, + * but we'll try to make a silk purse out of a sows ear ... + */ + /* generator 1 */ + a1ndx = ((isc_uint32_t) NSID_MULT_TABLE_SIZE * + (nsid_hash_state & 0xFFFF)) >> 16; + nsid->nsid_a1 = nsid_multiplier_table[a1ndx]; + c1ndx = (nsid_hash_state >> 9) & 0x7FFF; + nsid->nsid_c1 = 2 * c1ndx + 1; + + /* generator 2, distinct from 1 */ + a2ndx = ((isc_uint32_t) (NSID_MULT_TABLE_SIZE - 1) * + ((nsid_hash_state >> 10) & 0xFFFF)) >> 16; + if (a2ndx >= a1ndx) + a2ndx++; + nsid->nsid_a2 = nsid_multiplier_table[a2ndx]; + c2ndx = nsid_hash_state % 32767; + if (c2ndx >= c1ndx) + c2ndx++; + nsid->nsid_c2 = 2*c2ndx + 1; + + /* generator 3, distinct from 1 and 2 */ + a3ndx = ((isc_uint32_t) (NSID_MULT_TABLE_SIZE - 2) * + ((nsid_hash_state >> 20) & 0xFFFF)) >> 16; + if (a3ndx >= a1ndx || a3ndx >= a2ndx) + a3ndx++; + if (a3ndx >= a1ndx && a3ndx >= a2ndx) + a3ndx++; + nsid->nsid_a3 = nsid_multiplier_table[a3ndx]; + c3ndx = nsid_hash_state % 32766; + if (c3ndx >= c1ndx || c3ndx >= c2ndx) + c3ndx++; + if (c3ndx >= c1ndx && c3ndx >= c2ndx) + c3ndx++; + nsid->nsid_c3 = 2*c3ndx + 1; + + nsid->nsid_state = + ((nsid_hash_state >> 16) ^ (nsid_hash_state)) & 0xFFFF; + + nsid->nsid_usepool = usepool; + if (nsid->nsid_usepool) { + nsid->nsid_pool = isc_mem_get(mctx, 0x10000 * sizeof(isc_uint16_t)); + if (nsid->nsid_pool == NULL) + return (ISC_R_NOMEMORY); + for (i = 0; ; i++) { + nsid->nsid_pool[i] = nsid->nsid_state; + nsid->nsid_state = + (((u_long) nsid->nsid_a1 * nsid->nsid_state) + + nsid->nsid_c1) & 0xFFFF; + if (i == 0xFFFF) + break; + } + } else { + nsid->nsid_vtable = isc_mem_get(mctx, NSID_SHUFFLE_TABLE_SIZE * + (sizeof(isc_uint16_t)) ); + if (nsid->nsid_vtable == NULL) + return (ISC_R_NOMEMORY); + + for (i = 0; i < NSID_SHUFFLE_TABLE_SIZE; i++) { + nsid->nsid_vtable[i] = nsid->nsid_state; + nsid->nsid_state = + (((isc_uint32_t) nsid->nsid_a1 * nsid->nsid_state) + + nsid->nsid_c1) & 0xFFFF; + } + nsid->nsid_state2 = nsid->nsid_state; + } + return (ISC_R_SUCCESS); +} + +static void +nsid_destroy(isc_mem_t *mctx, dns_nsid_t *nsid) { + if (nsid->nsid_usepool) + isc_mem_put(mctx, nsid->nsid_pool, + 0x10000 * sizeof(isc_uint16_t)); + else + isc_mem_put(mctx, nsid->nsid_vtable, + NSID_SHUFFLE_TABLE_SIZE * (sizeof(isc_uint16_t)) ); + memset(nsid, 0, sizeof(*nsid)); +} + +void +dns_dispatch_hash(void *data, size_t len) { + nsid_hash(data, len); +} |
