[openldap] new feature: honor priority/weight with ldap_domain2hostlist
jvcelak
jvcelak at fedoraproject.org
Wed Aug 24 17:36:23 UTC 2011
commit a551ec94d31e38e4d3cfac7f631234c2f50f1566
Author: Jan Vcelak <jvcelak at redhat.com>
Date: Wed Aug 24 19:16:35 2011 +0200
new feature: honor priority/weight with ldap_domain2hostlist
Resolves: #733078
openldap-dns-priority.patch | 192 +++++++++++++++++++++++++++++++++++++++++++
openldap.spec | 3 +
2 files changed, 195 insertions(+), 0 deletions(-)
---
diff --git a/openldap-dns-priority.patch b/openldap-dns-priority.patch
new file mode 100644
index 0000000..13d9dcf
--- /dev/null
+++ b/openldap-dns-priority.patch
@@ -0,0 +1,192 @@
+Implement priority/weight for DNS SRV records
+
+From RFC 2782:
+
+ A client MUST attempt to contact the target host with the
+ lowest-numbered priority it can reach.
+
+This patch sorts the DNS SRV records by their priority, and
+additionally gives records with a larger weight a higher probability
+of appearing earlier. This way, the DNS SRV records are tried in the
+order of their priority.
+
+Author: James M Leddy <james.leddy at redhat.com>
+Upstream ITS: #7027
+Resolves: #733078
+
+---
+ libraries/libldap/dnssrv.c | 106 ++++++++++++++++++++++++++++++++++----------
+ 1 files changed, 83 insertions(+), 23 deletions(-)
+
+diff --git a/libraries/libldap/dnssrv.c b/libraries/libldap/dnssrv.c
+index 16b1544..40f93b4 100644
+--- a/libraries/libldap/dnssrv.c
++++ b/libraries/libldap/dnssrv.c
+@@ -174,6 +174,46 @@ int ldap_domain2dn(
+ return LDAP_SUCCESS;
+ }
+
++#ifdef HAVE_RES_QUERY
++#define DNSBUFSIZ (64*1024)
++typedef struct srv_record {
++ u_short priority;
++ u_short weight;
++ u_short port;
++ char hostname[DNSBUFSIZ];
++} srv_record;
++
++
++static int srv_cmp(const void *aa, const void *bb){
++ srv_record *a=(srv_record *)aa;
++ srv_record *b=(srv_record *)bb;
++ u_long total;
++
++ if(a->priority < b->priority) {
++ return -1;
++ }
++ if(a->priority > b->priority) {
++ return 1;
++ }
++ if(a->priority == b->priority){
++ /* targets with same priority are in psudeo random order */
++ if (a->weight == 0 && b->weight == 0) {
++ if (rand() % 2) {
++ return -1;
++ } else {
++ return 1;
++ }
++ }
++ total = a->weight + b->weight;
++ if (rand() % total < a->weight) {
++ return -1;
++ } else {
++ return 1;
++ }
++ }
++}
++#endif /* HAVE_RES_QUERY */
++
+ /*
+ * Lookup and return LDAP servers for domain (using the DNS
+ * SRV record _ldap._tcp.domain).
+@@ -183,15 +223,16 @@ int ldap_domain2hostlist(
+ char **list )
+ {
+ #ifdef HAVE_RES_QUERY
+-#define DNSBUFSIZ (64*1024)
+- char *request;
+- char *hostlist = NULL;
++ char *request;
++ char *hostlist = NULL;
++ srv_record *hostent_head=NULL;
++ int i;
+ 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;
+ }
+@@ -223,8 +264,7 @@ int ldap_domain2hostlist(
+ unsigned char *p;
+ char host[DNSBUFSIZ];
+ int status;
+- u_short port;
+- /* int priority, weight; */
++ u_short port, priority, weight;
+
+ /* Parse out query */
+ p = reply;
+@@ -263,40 +303,56 @@ int ldap_domain2hostlist(
+ size = (p[0] << 8) | p[1];
+ p += 2;
+ if (type == T_SRV) {
+- int buflen;
+ status = dn_expand(reply, reply + len, p + 6, host, sizeof(host));
+ if (status < 0) {
+ goto out;
+ }
+- /* ignore priority and weight for now */
+- /* priority = (p[0] << 8) | p[1]; */
+- /* weight = (p[2] << 8) | p[3]; */
++
++ /* 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;
+ }
+
+- buflen = strlen(host) + STRLENOF(":65355 ");
+- hostlist = (char *) LDAP_REALLOC(hostlist, cur + buflen + 1);
+- if (hostlist == NULL) {
+- rc = LDAP_NO_MEMORY;
+- goto out;
++ hostent_head = (srv_record *) LDAP_REALLOC(hostent_head, (hostent_count+1)*(sizeof(srv_record)));
++ if(hostent_head==NULL){
++ rc=LDAP_NO_MEMORY;
++ goto out;
++
+ }
+- if (cur > 0) {
+- /* not first time around */
+- hostlist[cur++] = ' ';
+- }
+- cur += sprintf(&hostlist[cur], "%s:%hu", host, port);
++ hostent_head[hostent_count].priority=priority;
++ hostent_head[hostent_count].weight=priority;
++ hostent_head[hostent_count].port=port;
++ strncpy(hostent_head[hostent_count].hostname, host,255);
++ hostent_count=hostent_count+1;
+ }
+ add_size:;
+ p += size;
+ }
+ }
++ qsort(hostent_head, hostent_count, sizeof(srv_record), srv_cmp);
++
++ for(i=0; i<hostent_count; i++){
++ int buflen;
++ buflen = strlen(hostent_head[i].hostname) + STRLENOF(":65355" );
++ 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:%hd", hostent_head[i].hostname, hostent_head[i].port);
++ }
++
+ if (hostlist == NULL) {
+- /* No LDAP servers found in DNS. */
+- rc = LDAP_UNAVAILABLE;
+- goto out;
++ /* No LDAP servers found in DNS. */
++ rc = LDAP_UNAVAILABLE;
++ goto out;
+ }
+
+ rc = LDAP_SUCCESS;
+@@ -308,8 +364,12 @@ add_size:;
+ 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
+--
+1.7.6
+
diff --git a/openldap.spec b/openldap.spec
index dd1d3f3..2411455 100644
--- a/openldap.spec
+++ b/openldap.spec
@@ -38,6 +38,7 @@ Patch12: openldap-constraint-overlay-config.patch
Patch13: openldap-dds-overlay-tolerance.patch
Patch14: openldap-man-slapo-unique.patch
Patch15: openldap-nss-wildcards.patch
+Patch16: openldap-dns-priority.patch
# patches for the evolution library (see README.evolution)
Patch200: openldap-evolution-ntlm.patch
@@ -146,6 +147,7 @@ pushd openldap-%{version}
%patch13 -p1 -b .dds-overlay-tolerance
%patch14 -p1 -b .man-slapo-unique
%patch15 -p1 -b .nss-wildcards
+%patch16 -p1 -b .dns-priority
cp %{_datadir}/libtool/config/config.{sub,guess} build/
@@ -678,6 +680,7 @@ exit 0
- fix: DDS overlay tolerance parametr doesn't function and breakes default TTL (#733069)
- manpage fix: errors in manual page slapo-unique (#733070)
- fix: matching wildcard hostnames in certificate Subject field does not work (#733073)
+- new feature: honor priority/weight with ldap_domain2hostlist (#733078)
* Sun Aug 14 2011 Rex Dieter <rdieter at fedoraproject.org> - 2.4.26-1.1
- Rebuilt for rpm (#728707)
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