* PERFORMANCE OF THIS SOFTWARE.
*/
-/* $ISC: dispatch.c,v 1.116.18.19 2007/08/28 07:20:04 tbox Exp $ */
+/* $ISC: dispatch.c,v 1.116.18.19.12.1 2008/05/22 21:28:06 each Exp $ */
/*! \file */
#include <unistd.h>
#include <isc/entropy.h>
-#include <isc/shuffle.h>
#include <isc/mem.h>
#include <isc/mutex.h>
#include <isc/print.h>
+#include <isc/random.h>
#include <isc/string.h>
#include <isc/task.h>
#include <isc/time.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;
- isc_shuffle_t qid_shuffle; /* state generator info */
- dns_nsid_t nsid;
dns_displist_t *qid_table; /*%< the table itself */
} dns_qid_t;
+/* ARC4 Random generator state */
+typedef struct arc4ctx {
+ isc_uint8_t i;
+ isc_uint8_t j;
+ isc_uint8_t s[256];
+ int count;
+} arc4ctx_t;
+
struct dns_dispatchmgr {
/* Unlocked. */
unsigned int magic;
unsigned int state;
ISC_LIST(dns_dispatch_t) list;
+ /* Locked by arc4_lock. */
+ isc_mutex_t arc4_lock;
+ arc4ctx_t arc4ctx; /*%< ARC4 context for QID */
+
/* locked by buffer lock */
dns_qid_t *qid;
isc_mutex_t buffer_lock;
unsigned int magic;
dns_dispatch_t *disp;
dns_messageid_t id;
+ in_port_t port;
unsigned int bucket;
isc_sockaddr_t host;
isc_task_t *task;
isc_task_t *task; /*%< internal task */
isc_socket_t *socket; /*%< isc socket attached to */
isc_sockaddr_t local; /*%< local address */
+ in_port_t localport; /*%< local UDP port */
unsigned int maxrequests; /*%< max requests */
isc_event_t *ctlevent;
* Statics.
*/
static dns_dispentry_t *bucket_search(dns_qid_t *, isc_sockaddr_t *,
- dns_messageid_t, unsigned int);
+ dns_messageid_t, in_port_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_qid_t *);
-static isc_uint32_t dns_hash(dns_qid_t *, isc_sockaddr_t *, dns_messageid_t);
+static isc_uint32_t dns_hash(dns_qid_t *, isc_sockaddr_t *, dns_messageid_t,
+ in_port_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 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);
+ unsigned int increment, 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)
}
/*
- * Return an unpredictable message ID.
+ * ARC4 random number generator obtained from OpenBSD
*/
-static dns_messageid_t
-dns_randomid(dns_qid_t *qid) {
- isc_uint16_t id;
+static void
+dispatch_arc4init(arc4ctx_t *actx) {
+ int n;
+ for (n = 0; n < 256; n++)
+ actx->s[n] = n;
+ actx->i = 0;
+ actx->j = 0;
+ actx->count = 0;
+}
+
+static void
+dispatch_arc4addrandom(arc4ctx_t *actx, unsigned char *dat, int datlen) {
+ int n;
+ isc_uint8_t si;
+
+ actx->i--;
+ for (n = 0; n < 256; n++) {
+ actx->i = (actx->i + 1);
+ si = actx->s[actx->i];
+ actx->j = (actx->j + si + dat[n % datlen]);
+ actx->s[actx->i] = actx->s[actx->j];
+ actx->s[actx->j] = si;
+ }
+ actx->j = actx->i;
+}
+
+static inline isc_uint8_t
+dispatch_arc4get8(arc4ctx_t *actx) {
+ isc_uint8_t si, sj;
+
+ actx->i = (actx->i + 1);
+ si = actx->s[actx->i];
+ actx->j = (actx->j + si);
+ sj = actx->s[actx->j];
+ actx->s[actx->i] = sj;
+ actx->s[actx->j] = si;
+
+ return (actx->s[(si + sj) & 0xff]);
+}
+
+static inline isc_uint16_t
+dispatch_arc4get16(arc4ctx_t *actx) {
+ isc_uint16_t val;
+
+ val = dispatch_arc4get8(actx) << 8;
+ val |= dispatch_arc4get8(actx);
+
+ return (val);
+}
+
+static void
+dispatch_arc4stir(dns_dispatchmgr_t *mgr) {
+ int i;
+ union {
+ unsigned char rnd[128];
+ isc_uint32_t rnd32[32];
+ } rnd;
+ isc_result_t result;
+
+ if (mgr->entropy != NULL) {
+ /*
+ * We accept any quality of random data to avoid blocking.
+ */
+ result = isc_entropy_getdata(mgr->entropy, rnd.rnd,
+ sizeof(rnd), NULL, 0);
+ RUNTIME_CHECK(result == ISC_R_SUCCESS);
+ } else {
+ for (i = 0; i < 32; i++)
+ isc_random_get(&rnd.rnd32[i]);
+ }
+ dispatch_arc4addrandom(&mgr->arc4ctx, rnd.rnd, sizeof(rnd.rnd));
+
+ /*
+ * Discard early keystream, as per recommendations in:
+ * http://www.wisdom.weizmann.ac.il/~itsik/RC4/Papers/Rc4_ksa.ps
+ */
+ for (i = 0; i < 256; i++)
+ (void)dispatch_arc4get8(&mgr->arc4ctx);
+
+ /*
+ * Derived from OpenBSD's implementation. The rationale is not clear,
+ * but should be conservative enough in safety, and reasonably large
+ * for efficiency.
+ */
+ mgr->arc4ctx.count = 1600000;
+}
+
+static isc_uint16_t
+dispatch_arc4random(dns_dispatchmgr_t *mgr) {
+ isc_uint16_t result;
+
+ LOCK(&mgr->arc4_lock);
+ mgr->arc4ctx.count -= sizeof(isc_uint16_t);
+ if (mgr->arc4ctx.count <= 0)
+ dispatch_arc4stir(mgr);
+ result = dispatch_arc4get16(&mgr->arc4ctx);
+ UNLOCK(&mgr->arc4_lock);
+ return (result);
+}
+
+static isc_uint16_t
+dispatch_arc4uniformrandom(dns_dispatchmgr_t *mgr, isc_uint16_t upper_bound) {
+ isc_uint16_t min, r;
+ /* The caller must hold the manager lock. */
- id = isc_shuffle_generate16(&qid->qid_shuffle);
+ if (upper_bound < 2)
+ return (0);
- return ((dns_messageid_t)id);
+ /*
+ * Ensure the range of random numbers [min, 0xffff] be a multiple of
+ * upper_bound and contain at least a half of the 16 bit range.
+ */
+
+ if (upper_bound > 0x8000)
+ min = 1 + ~upper_bound; /* 0x8000 - upper_bound */
+ else
+ min = (isc_uint16_t)(0x10000 % (isc_uint32_t)upper_bound);
+
+ /*
+ * This could theoretically loop forever but each retry has
+ * p > 0.5 (worst case, usually far better) of selecting a
+ * number inside the range we need, so it should rarely need
+ * to re-roll.
+ */
+ for (;;) {
+ r = dispatch_arc4random(mgr);
+ if (r >= min)
+ break;
+ }
+
+ return (r % upper_bound);
}
/*
* 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) {
+dns_hash(dns_qid_t *qid, isc_sockaddr_t *dest, dns_messageid_t id,
+ in_port_t port)
+{
unsigned int ret;
ret = isc_sockaddr_hash(dest, ISC_TRUE);
- ret ^= id;
+ ret ^= (id << 16) | port;
ret %= qid->qid_nbuckets;
INSIST(ret < qid->qid_nbuckets);
*/
static dns_dispentry_t *
bucket_search(dns_qid_t *qid, isc_sockaddr_t *dest, dns_messageid_t id,
- unsigned int bucket)
+ in_port_t port, unsigned int bucket)
{
dns_dispentry_t *res;
res = ISC_LIST_HEAD(qid->qid_table[bucket]);
while (res != NULL) {
- if ((res->id == id) && isc_sockaddr_equal(dest, &res->host))
+ if ((res->id == id) && isc_sockaddr_equal(dest, &res->host) &&
+ res->port == port) {
return (res);
+ }
res = ISC_LIST_NEXT(res, link);
}
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);
+ bucket = dns_hash(qid, &ev->address, id, disp->localport);
LOCK(&qid->lock);
- resp = bucket_search(qid, &ev->address, id, bucket);
+ resp = bucket_search(qid, &ev->address, id, disp->localport, bucket);
dispatch_log(disp, LVL(90),
"search for response in bucket %d: %s",
bucket, (resp == NULL ? "not found" : "found"));
goto restart;
}
- dns_dispatch_hash(tcpmsg->buffer.base, tcpmsg->buffer.length);
-
/*
* Response.
*/
- bucket = dns_hash(qid, &tcpmsg->address, id);
+ bucket = dns_hash(qid, &tcpmsg->address, id, disp->localport);
LOCK(&qid->lock);
- resp = bucket_search(qid, &tcpmsg->address, id, bucket);
+ resp = bucket_search(qid, &tcpmsg->address, id, disp->localport,
+ bucket);
dispatch_log(disp, LVL(90),
"search for response in bucket %d: %s",
bucket, (resp == NULL ? "not found" : "found"));
DESTROYLOCK(&mgr->lock);
mgr->state = 0;
+ DESTROYLOCK(&mgr->arc4_lock);
+
isc_mempool_destroy(&mgr->epool);
isc_mempool_destroy(&mgr->rpool);
isc_mempool_destroy(&mgr->dpool);
if (result != ISC_R_SUCCESS)
goto deallocate;
- result = isc_mutex_init(&mgr->buffer_lock);
+ result = isc_mutex_init(&mgr->arc4_lock);
if (result != ISC_R_SUCCESS)
goto kill_lock;
+ result = isc_mutex_init(&mgr->buffer_lock);
+ if (result != ISC_R_SUCCESS)
+ goto kill_arc4_lock;
+
result = isc_mutex_init(&mgr->pool_lock);
if (result != ISC_R_SUCCESS)
goto kill_buffer_lock;
if (entropy != NULL)
isc_entropy_attach(entropy, &mgr->entropy);
+ dispatch_arc4init(&mgr->arc4ctx);
+
*mgrp = mgr;
return (ISC_R_SUCCESS);
DESTROYLOCK(&mgr->pool_lock);
kill_buffer_lock:
DESTROYLOCK(&mgr->buffer_lock);
+ kill_arc4_lock:
+ DESTROYLOCK(&mgr->arc4_lock);
kill_lock:
DESTROYLOCK(&mgr->lock);
deallocate:
isc_mempool_setmaxalloc(mgr->bpool, maxbuffers);
isc_mempool_associatelock(mgr->bpool, &mgr->pool_lock);
- result = qid_allocate(mgr, buckets, increment, ISC_TRUE, &mgr->qid);
+ result = qid_allocate(mgr, buckets, increment, &mgr->qid);
if (result != ISC_R_SUCCESS)
goto cleanup;
}
static isc_boolean_t
-blacklisted(dns_dispatchmgr_t *mgr, isc_socket_t *sock) {
+blacklisted(dns_dispatchmgr_t *mgr, isc_socket_t *sock,
+ isc_sockaddr_t *sockaddrp)
+{
isc_sockaddr_t sockaddr;
isc_result_t result;
+ REQUIRE(sock != NULL || sockaddrp != NULL);
+
if (mgr->portlist == NULL)
return (ISC_FALSE);
- result = isc_socket_getsockname(sock, &sockaddr);
- if (result != ISC_R_SUCCESS)
- return (ISC_FALSE);
+ if (sock != NULL) {
+ sockaddrp = &sockaddr;
+ result = isc_socket_getsockname(sock, sockaddrp);
+ 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)))
+ dns_portlist_match(mgr->portlist, isc_sockaddr_pf(sockaddrp),
+ isc_sockaddr_getport(sockaddrp)))
return (ISC_TRUE);
return (ISC_FALSE);
}
if (disp->mgr->portlist != NULL &&
isc_sockaddr_getport(addr) == 0 &&
isc_sockaddr_getport(&disp->local) == 0 &&
- blacklisted(disp->mgr, disp->socket))
+ blacklisted(disp->mgr, disp->socket, NULL))
return (ISC_FALSE);
/*
static isc_result_t
qid_allocate(dns_dispatchmgr_t *mgr, unsigned int buckets,
- unsigned int increment, isc_boolean_t usepool, dns_qid_t **qidp)
+ unsigned int increment, dns_qid_t **qidp)
{
dns_qid_t *qid;
unsigned int i;
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));
qid->qid_nbuckets = buckets;
qid->qid_increment = increment;
qid->magic = QID_MAGIC;
-
- isc_shuffle_init(&qid->qid_shuffle);
-
*qidp = qid;
return (ISC_R_SUCCESS);
}
*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);
disp->refcount = 1;
disp->recv_pending = 0;
memset(&disp->local, 0, sizeof(disp->local));
+ disp->localport = 0;
disp->shutting_down = 0;
disp->shutdown_out = 0;
disp->connected = 0;
return (result);
}
- result = qid_allocate(mgr, buckets, increment, ISC_FALSE, &disp->qid);
+ result = qid_allocate(mgr, buckets, increment, &disp->qid);
if (result != ISC_R_SUCCESS)
goto deallocate_dispatch;
dns_dispatch_t **dispp)
{
isc_result_t result;
- dns_dispatch_t *disp;
+ dns_dispatch_t *disp = NULL;
REQUIRE(VALID_DISPATCHMGR(mgr));
REQUIRE(sockmgr != NULL);
LOCK(&mgr->lock);
+ if ((attributes & DNS_DISPATCHATTR_RANDOMPORT) != 0) {
+ REQUIRE(isc_sockaddr_getport(localaddr) == 0);
+ goto createudp;
+ }
+
/*
* First, see if we have a dispatcher that matches.
*/
return (ISC_R_SUCCESS);
}
+ createudp:
/*
* Nope, create one.
*/
dns_dispatch_t *disp;
isc_socket_t *sock = NULL;
isc_socket_t *held[DNS_DISPATCH_HELD];
- unsigned int i = 0, j = 0;
+ unsigned int i = 0, j = 0, k = 0;
+ isc_sockaddr_t localaddr_bound;
+ in_port_t localport = 0;
/*
* dispatch_allocate() checks mgr for us.
* from returning the same port to us too quickly.
*/
memset(held, 0, sizeof(held));
+ localaddr_bound = *localaddr;
getsocket:
- result = create_socket(sockmgr, localaddr, &sock);
+ if ((attributes & DNS_DISPATCHATTR_RANDOMPORT) != 0) {
+ in_port_t prt;
+
+ /* XXX: should the range be configurable? */
+ prt = 1024 + dispatch_arc4uniformrandom(mgr, 65535 - 1023);
+ isc_sockaddr_setport(&localaddr_bound, prt);
+ if (blacklisted(mgr, NULL, &localaddr_bound)) {
+ if (++k == 1024)
+ attributes &= ~DNS_DISPATCHATTR_RANDOMPORT;
+ goto getsocket;
+ }
+ result = create_socket(sockmgr, &localaddr_bound, &sock);
+ if (result == ISC_R_ADDRINUSE) {
+ if (++k == 1024)
+ attributes &= ~DNS_DISPATCHATTR_RANDOMPORT;
+ goto getsocket;
+ }
+ localport = prt;
+ } else
+ result = create_socket(sockmgr, localaddr, &sock);
if (result != ISC_R_SUCCESS)
goto deallocate_dispatch;
- if (isc_sockaddr_getport(localaddr) == 0 && blacklisted(mgr, sock)) {
+ if ((attributes & DNS_DISPATCHATTR_RANDOMPORT) == 0 &&
+ isc_sockaddr_getport(localaddr) == 0 &&
+ blacklisted(mgr, sock, NULL))
+ {
if (held[i] != NULL)
isc_socket_detach(&held[i]);
held[i++] = sock;
disp->socktype = isc_sockettype_udp;
disp->socket = sock;
disp->local = *localaddr;
+ disp->localport = localport;
disp->task = NULL;
result = isc_task_create(taskmgr, 0, &disp->task);
/*
* Try somewhat hard to find an unique ID.
*/
+ id = (dns_messageid_t)dispatch_arc4random(disp->mgr);
qid = DNS_QID(disp);
LOCK(&qid->lock);
- id = dns_randomid(qid);
- bucket = dns_hash(qid, dest, id);
+ bucket = dns_hash(qid, dest, id, disp->localport);
ok = ISC_FALSE;
for (i = 0; i < 64; i++) {
- if (bucket_search(qid, dest, id, bucket) == NULL) {
+ if (bucket_search(qid, dest, id, disp->localport, bucket) ==
+ NULL) {
ok = ISC_TRUE;
break;
}
id += qid->qid_increment;
id &= 0x0000ffff;
- bucket = dns_hash(qid, dest, id);
+ bucket = dns_hash(qid, dest, id, disp->localport);
}
if (!ok) {
isc_task_attach(task, &res->task);
res->disp = disp;
res->id = id;
+ res->port = disp->localport;
res->bucket = bucket;
res->host = *dest;
res->action = action;
}
}
#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);
-}
projects / openbsd / commitdiff