summaryrefslogtreecommitdiffstats
path: root/libraries/libldap/dnssrv.c
diff options
context:
space:
mode:
Diffstat (limited to 'libraries/libldap/dnssrv.c')
-rw-r--r--libraries/libldap/dnssrv.c422
1 files changed, 422 insertions, 0 deletions
diff --git a/libraries/libldap/dnssrv.c b/libraries/libldap/dnssrv.c
new file mode 100644
index 0000000..433c37f
--- /dev/null
+++ b/libraries/libldap/dnssrv.c
@@ -0,0 +1,422 @@
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 1998-2022 The OpenLDAP Foundation.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+
+/*
+ * locate LDAP servers using DNS SRV records.
+ * Location code based on MIT Kerberos KDC location code.
+ */
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/stdlib.h>
+
+#include <ac/param.h>
+#include <ac/socket.h>
+#include <ac/string.h>
+#include <ac/time.h>
+
+#include "ldap-int.h"
+
+#ifdef HAVE_ARPA_NAMESER_H
+#include <arpa/nameser.h>
+#endif
+#ifdef HAVE_RESOLV_H
+#include <resolv.h>
+#endif
+
+int ldap_dn2domain(
+ LDAP_CONST char *dn_in,
+ char **domainp)
+{
+ int i, j;
+ char *ndomain;
+ LDAPDN dn = NULL;
+ LDAPRDN rdn = NULL;
+ LDAPAVA *ava = NULL;
+ struct berval domain = BER_BVNULL;
+ static const struct berval DC = BER_BVC("DC");
+ static const struct berval DCOID = BER_BVC("0.9.2342.19200300.100.1.25");
+
+ assert( dn_in != NULL );
+ assert( domainp != NULL );
+
+ *domainp = NULL;
+
+ if ( ldap_str2dn( dn_in, &dn, LDAP_DN_FORMAT_LDAP ) != LDAP_SUCCESS ) {
+ return -2;
+ }
+
+ if( dn ) for( i=0; dn[i] != NULL; i++ ) {
+ rdn = dn[i];
+
+ for( j=0; rdn[j] != NULL; j++ ) {
+ ava = rdn[j];
+
+ if( rdn[j+1] == NULL &&
+ (ava->la_flags & LDAP_AVA_STRING) &&
+ ava->la_value.bv_len &&
+ ( ber_bvstrcasecmp( &ava->la_attr, &DC ) == 0
+ || ber_bvcmp( &ava->la_attr, &DCOID ) == 0 ) )
+ {
+ if( domain.bv_len == 0 ) {
+ ndomain = LDAP_REALLOC( domain.bv_val,
+ ava->la_value.bv_len + 1);
+
+ if( ndomain == NULL ) {
+ goto return_error;
+ }
+
+ domain.bv_val = ndomain;
+
+ AC_MEMCPY( domain.bv_val, ava->la_value.bv_val,
+ ava->la_value.bv_len );
+
+ domain.bv_len = ava->la_value.bv_len;
+ domain.bv_val[domain.bv_len] = '\0';
+
+ } else {
+ ndomain = LDAP_REALLOC( domain.bv_val,
+ ava->la_value.bv_len + sizeof(".") + domain.bv_len );
+
+ if( ndomain == NULL ) {
+ goto return_error;
+ }
+
+ domain.bv_val = ndomain;
+ domain.bv_val[domain.bv_len++] = '.';
+ AC_MEMCPY( &domain.bv_val[domain.bv_len],
+ ava->la_value.bv_val, ava->la_value.bv_len );
+ domain.bv_len += ava->la_value.bv_len;
+ domain.bv_val[domain.bv_len] = '\0';
+ }
+ } else {
+ domain.bv_len = 0;
+ }
+ }
+ }
+
+
+ if( domain.bv_len == 0 && domain.bv_val != NULL ) {
+ LDAP_FREE( domain.bv_val );
+ domain.bv_val = NULL;
+ }
+
+ ldap_dnfree( dn );
+ *domainp = domain.bv_val;
+ return 0;
+
+return_error:
+ ldap_dnfree( dn );
+ LDAP_FREE( domain.bv_val );
+ return -1;
+}
+
+int ldap_domain2dn(
+ LDAP_CONST char *domain_in,
+ char **dnp)
+{
+ char *domain, *s, *tok_r, *dn, *dntmp;
+ size_t loc;
+
+ assert( domain_in != NULL );
+ assert( dnp != NULL );
+
+ domain = LDAP_STRDUP(domain_in);
+ if (domain == NULL) {
+ return LDAP_NO_MEMORY;
+ }
+ dn = NULL;
+ loc = 0;
+
+ for (s = ldap_pvt_strtok(domain, ".", &tok_r);
+ s != NULL;
+ s = ldap_pvt_strtok(NULL, ".", &tok_r))
+ {
+ size_t len = strlen(s);
+
+ dntmp = (char *) LDAP_REALLOC(dn, loc + sizeof(",dc=") + len );
+ if (dntmp == NULL) {
+ if (dn != NULL)
+ LDAP_FREE(dn);
+ LDAP_FREE(domain);
+ return LDAP_NO_MEMORY;
+ }
+
+ dn = dntmp;
+
+ if (loc > 0) {
+ /* not first time. */
+ strcpy(dn + loc, ",");
+ loc++;
+ }
+ strcpy(dn + loc, "dc=");
+ loc += sizeof("dc=")-1;
+
+ strcpy(dn + loc, s);
+ loc += len;
+ }
+
+ LDAP_FREE(domain);
+ *dnp = dn;
+ return LDAP_SUCCESS;
+}
+
+#ifdef HAVE_RES_QUERY
+#define DNSBUFSIZ (64*1024)
+#define MAXHOST 254 /* RFC 1034, max length is 253 chars */
+typedef struct srv_record {
+ u_short priority;
+ u_short weight;
+ u_short port;
+ char hostname[MAXHOST];
+} srv_record;
+
+/* Linear Congruential Generator - we don't need
+ * high quality randomness, and we don't want to
+ * interfere with anyone else's use of srand().
+ *
+ * The PRNG here cycles thru 941,955 numbers.
+ */
+static float srv_seed;
+
+static void srv_srand(int seed) {
+ srv_seed = (float)seed / (float)RAND_MAX;
+}
+
+static float srv_rand() {
+ float val = 9821.0 * srv_seed + .211327;
+ srv_seed = val - (int)val;
+ return srv_seed;
+}
+
+static int srv_cmp(const void *aa, const void *bb){
+ srv_record *a=(srv_record *)aa;
+ srv_record *b=(srv_record *)bb;
+ int i = a->priority - b->priority;
+ if (i) return i;
+ return b->weight - a->weight;
+}
+
+static void srv_shuffle(srv_record *a, int n) {
+ int i, j, total = 0, r, p;
+
+ for (i=0; i<n; i++)
+ total += a[i].weight;
+
+ /* Do a shuffle per RFC2782 Page 4 */
+ for (p=n; p>1; a++, p--) {
+ if (!total) {
+ /* all remaining weights are zero,
+ do a straight Fisher-Yates shuffle */
+ j = srv_rand() * p;
+ } else {
+ r = srv_rand() * total;
+ for (j=0; j<p; j++) {
+ r -= a[j].weight;
+ if (r < 0) {
+ total -= a[j].weight;
+ break;
+ }
+ }
+ }
+ if (j && j<p) {
+ srv_record t = a[0];
+ a[0] = a[j];
+ a[j] = t;
+ }
+ }
+}
+#endif /* HAVE_RES_QUERY */
+
+/*
+ * Lookup and return LDAP servers for domain (using the DNS
+ * SRV record _ldap._tcp.domain).
+ */
+int ldap_domain2hostlist(
+ LDAP_CONST char *domain,
+ char **list )
+{
+#ifdef HAVE_RES_QUERY
+ char *request;
+ char *hostlist = NULL;
+ srv_record *hostent_head=NULL;
+ int i, j;
+ int rc, len, cur = 0;
+ unsigned char reply[DNSBUFSIZ];
+ int hostent_count=0;
+
+ assert( domain != NULL );
+ assert( list != NULL );
+ if( *domain == '\0' ) {
+ return LDAP_PARAM_ERROR;
+ }
+
+ request = LDAP_MALLOC(strlen(domain) + sizeof("_ldap._tcp."));
+ if (request == NULL) {
+ return LDAP_NO_MEMORY;
+ }
+ sprintf(request, "_ldap._tcp.%s", domain);
+
+ LDAP_MUTEX_LOCK(&ldap_int_resolv_mutex);
+
+ rc = LDAP_UNAVAILABLE;
+#ifdef NS_HFIXEDSZ
+ /* Bind 8/9 interface */
+ len = res_query(request, ns_c_in, ns_t_srv, reply, sizeof(reply));
+# ifndef T_SRV
+# define T_SRV ns_t_srv
+# endif
+#else
+ /* Bind 4 interface */
+# ifndef T_SRV
+# define T_SRV 33
+# endif
+
+ len = res_query(request, C_IN, T_SRV, reply, sizeof(reply));
+#endif
+ if (len >= 0) {
+ unsigned char *p;
+ char host[DNSBUFSIZ];
+ int status;
+ u_short port, priority, weight;
+
+ /* Parse out query */
+ p = reply;
+
+#ifdef NS_HFIXEDSZ
+ /* Bind 8/9 interface */
+ p += NS_HFIXEDSZ;
+#elif defined(HFIXEDSZ)
+ /* Bind 4 interface w/ HFIXEDSZ */
+ p += HFIXEDSZ;
+#else
+ /* Bind 4 interface w/o HFIXEDSZ */
+ p += sizeof(HEADER);
+#endif
+
+ status = dn_expand(reply, reply + len, p, host, sizeof(host));
+ if (status < 0) {
+ goto out;
+ }
+ p += status;
+ p += 4;
+
+ while (p < reply + len) {
+ int type, class, ttl, size;
+ status = dn_expand(reply, reply + len, p, host, sizeof(host));
+ if (status < 0) {
+ goto out;
+ }
+ p += status;
+ type = (p[0] << 8) | p[1];
+ p += 2;
+ class = (p[0] << 8) | p[1];
+ p += 2;
+ ttl = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
+ p += 4;
+ size = (p[0] << 8) | p[1];
+ p += 2;
+ if (type == T_SRV) {
+ status = dn_expand(reply, reply + len, p + 6, host, sizeof(host));
+ if (status < 0) {
+ goto out;
+ }
+
+ /* Get priority weight and port */
+ priority = (p[0] << 8) | p[1];
+ weight = (p[2] << 8) | p[3];
+ port = (p[4] << 8) | p[5];
+
+ if ( port == 0 || host[ 0 ] == '\0' ) {
+ goto add_size;
+ }
+
+ hostent_head = (srv_record *) LDAP_REALLOC(hostent_head, (hostent_count+1)*(sizeof(srv_record)));
+ if(hostent_head==NULL){
+ rc=LDAP_NO_MEMORY;
+ goto out;
+ }
+ hostent_head[hostent_count].priority=priority;
+ hostent_head[hostent_count].weight=weight;
+ hostent_head[hostent_count].port=port;
+ strncpy(hostent_head[hostent_count].hostname, host, MAXHOST-1);
+ hostent_head[hostent_count].hostname[MAXHOST-1] = '\0';
+ hostent_count++;
+ }
+add_size:;
+ p += size;
+ }
+ if (!hostent_head) goto out;
+ qsort(hostent_head, hostent_count, sizeof(srv_record), srv_cmp);
+
+ if (!srv_seed)
+ srv_srand(time(0L));
+
+ /* shuffle records of same priority */
+ j = 0;
+ priority = hostent_head[0].priority;
+ for (i=1; i<hostent_count; i++) {
+ if (hostent_head[i].priority != priority) {
+ priority = hostent_head[i].priority;
+ if (i-j > 1)
+ srv_shuffle(hostent_head+j, i-j);
+ j = i;
+ }
+ }
+ if (i-j > 1)
+ srv_shuffle(hostent_head+j, i-j);
+
+ for(i=0; i<hostent_count; i++){
+ int buflen;
+ buflen = strlen(hostent_head[i].hostname) + STRLENOF(":65535 ");
+ hostlist = (char *) LDAP_REALLOC(hostlist, cur+buflen+1);
+ if (hostlist == NULL) {
+ rc = LDAP_NO_MEMORY;
+ goto out;
+ }
+ if(cur>0){
+ hostlist[cur++]=' ';
+ }
+ cur += sprintf(&hostlist[cur], "%s:%hu", hostent_head[i].hostname, hostent_head[i].port);
+ }
+ }
+
+ if (hostlist == NULL) {
+ /* No LDAP servers found in DNS. */
+ rc = LDAP_UNAVAILABLE;
+ goto out;
+ }
+
+ rc = LDAP_SUCCESS;
+ *list = hostlist;
+
+ out:
+ LDAP_MUTEX_UNLOCK(&ldap_int_resolv_mutex);
+
+ if (request != NULL) {
+ LDAP_FREE(request);
+ }
+ if (hostent_head != NULL) {
+ LDAP_FREE(hostent_head);
+ }
+ if (rc != LDAP_SUCCESS && hostlist != NULL) {
+ LDAP_FREE(hostlist);
+ }
+ return rc;
+#else
+ return LDAP_NOT_SUPPORTED;
+#endif /* HAVE_RES_QUERY */
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-06 11:44:56 +0000