3633. [cleanup] Refactor OPT processing in named to make it easier

                        to support new EDNS options. [RT #34414]

(cherry picked from commit 8e091f3d3ee0079f35dfccdc4479105e8f087ab2)

diff --git a/CHANGES b/CHANGES
index e048272d4c92b5a0eaf27bb42dea124edcfbae3f..56213fcedbb57524a42941cad8e5729d28eb5c65 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+3633.  [cleanup]       Refactor OPT processing in named to make it easier
+                       to support new EDNS options. [RT #34414]
+
 3631.  [bug]           Remove spurious warning about missing signatures when
                        qtype is SIG. [RT #34600]
 

diff --git a/bin/named/client.c b/bin/named/client.c
index d090061b8341133540483e0a5b1c79f9d93433ec..e5a9351c3c76efbdaf8f8810545b052f663e832c 100644 (file)
--- a/bin/named/client.c
+++ b/bin/named/client.c
@@ -1170,62 +1170,30 @@ ns_client_error(ns_client_t *client, isc_result_t result) {
 
 static inline isc_result_t
 client_addopt(ns_client_t *client) {
-       dns_rdataset_t *rdataset;
-       dns_rdatalist_t *rdatalist;
-       dns_rdata_t *rdata;
+       char nsid[BUFSIZ], *nsidp;
        isc_result_t result;
        dns_view_t *view;
        dns_resolver_t *resolver;
        isc_uint16_t udpsize;
+       dns_ednsopt_t ednsopts[2];
+       int count = 0;
+       unsigned int flags;
 
        REQUIRE(client->opt == NULL);   /* XXXRTH free old. */
 
-       rdatalist = NULL;
-       result = dns_message_gettemprdatalist(client->message, &rdatalist);
-       if (result != ISC_R_SUCCESS)
-               return (result);
-       rdata = NULL;
-       result = dns_message_gettemprdata(client->message, &rdata);
-       if (result != ISC_R_SUCCESS)
-               return (result);
-       rdataset = NULL;
-       result = dns_message_gettemprdataset(client->message, &rdataset);
-       if (result != ISC_R_SUCCESS)
-               return (result);
-       dns_rdataset_init(rdataset);
-
-       rdatalist->type = dns_rdatatype_opt;
-       rdatalist->covers = 0;
-
-       /*
-        * Set the maximum UDP buffer size.
-        */
        view = client->view;
        resolver = (view != NULL) ? view->resolver : NULL;
        if (resolver != NULL)
                udpsize = dns_resolver_getudpsize(resolver);
        else
                udpsize = ns_g_udpsize;
-       rdatalist->rdclass = udpsize;
 
-       /*
-        * Set EXTENDED-RCODE, VERSION and Z to 0.
-        */
-       rdatalist->ttl = (client->extflags & DNS_MESSAGEEXTFLAG_REPLYPRESERVE);
+       flags = client->extflags & DNS_MESSAGEEXTFLAG_REPLYPRESERVE;
 
        /* Set EDNS options if applicable */
-       if (client->attributes & NS_CLIENTATTR_WANTNSID &&
+       if ((client->attributes & NS_CLIENTATTR_WANTNSID) != 0 &&
            (ns_g_server->server_id != NULL ||
             ns_g_server->server_usehostname)) {
-               /*
-                * Space required for NSID data:
-                *   2 bytes for opt code
-                * + 2 bytes for NSID length
-                * + NSID itself
-                */
-               char nsid[BUFSIZ], *nsidp;
-               isc_buffer_t *buffer = NULL;
-
                if (ns_g_server->server_usehostname) {
                        isc_result_t result;
                        result = ns_os_gethostname(nsid, sizeof(nsid));
@@ -1236,35 +1204,15 @@ client_addopt(ns_client_t *client) {
                } else
                        nsidp = ns_g_server->server_id;
 
-               rdata->length = strlen(nsidp) + 4;
-               result = isc_buffer_allocate(client->mctx, &buffer,
-                                            rdata->length);
-               if (result != ISC_R_SUCCESS)
-                       goto no_nsid;
-
-               isc_buffer_putuint16(buffer, DNS_OPT_NSID);
-               isc_buffer_putuint16(buffer, strlen(nsidp));
-               isc_buffer_putstr(buffer, nsidp);
-               rdata->data = buffer->base;
-               dns_message_takebuffer(client->message, &buffer);
-       } else {
-no_nsid:
-               rdata->data = NULL;
-               rdata->length = 0;
+               ednsopts[count].code = DNS_OPT_NSID;
+               ednsopts[count].length = strlen(nsidp);
+               ednsopts[count].value = (unsigned char *)nsidp;
+               count++;
        }
-
-       rdata->rdclass = rdatalist->rdclass;
-       rdata->type = rdatalist->type;
-       rdata->flags = 0;
-
-       ISC_LIST_INIT(rdatalist->rdata);
-       ISC_LIST_APPEND(rdatalist->rdata, rdata, link);
-       RUNTIME_CHECK(dns_rdatalist_tordataset(rdatalist, rdataset)
-                     == ISC_R_SUCCESS);
-
-       client->opt = rdataset;
-
-       return (ISC_R_SUCCESS);
+ no_nsid:
+       result = dns_message_buildopt(client->message, &client->opt, 0,
+                                     udpsize, flags, ednsopts, count);
+       return (result);
 }
 
 static inline isc_boolean_t
@@ -1345,6 +1293,83 @@ ns_client_isself(dns_view_t *myview, dns_tsigkey_t *mykey,
        return (ISC_TF(view == myview));
 }
 
+static isc_result_t
+process_opt(ns_client_t *client, dns_rdataset_t *opt) {
+       dns_rdata_t rdata;
+       isc_buffer_t optbuf;
+       isc_result_t result;
+       isc_uint16_t optcode;
+       isc_uint16_t optlen;
+
+       /*
+        * Set the client's UDP buffer size.
+        */
+       client->udpsize = opt->rdclass;
+
+       /*
+        * If the requested UDP buffer size is less than 512,
+        * ignore it and use 512.
+        */
+       if (client->udpsize < 512)
+               client->udpsize = 512;
+
+       /*
+        * Get the flags out of the OPT record.
+        */
+       client->extflags = (isc_uint16_t)(opt->ttl & 0xFFFF);
+
+       /*
+        * Do we understand this version of EDNS?
+        *
+        * XXXRTH need library support for this!
+        */
+       client->ednsversion = (opt->ttl & 0x00FF0000) >> 16;
+       if (client->ednsversion > 0) {
+               isc_stats_increment(ns_g_server->nsstats,
+                                   dns_nsstatscounter_badednsver);
+               result = client_addopt(client);
+               if (result == ISC_R_SUCCESS)
+                       result = DNS_R_BADVERS;
+               ns_client_error(client, result);
+               goto cleanup;
+       }
+
+       /* Check for NSID request */
+       result = dns_rdataset_first(opt);
+       if (result == ISC_R_SUCCESS) {
+               dns_rdata_init(&rdata);
+               dns_rdataset_current(opt, &rdata);
+               isc_buffer_init(&optbuf, rdata.data, rdata.length);
+               isc_buffer_add(&optbuf, rdata.length);
+               while (isc_buffer_remaininglength(&optbuf) >= 4) {
+                       optcode = isc_buffer_getuint16(&optbuf);
+                       optlen = isc_buffer_getuint16(&optbuf);
+                       switch (optcode) {
+                       case DNS_OPT_NSID:
+                               client->attributes |= NS_CLIENTATTR_WANTNSID;
+                               isc_buffer_forward(&optbuf, optlen);
+                               break;
+                       default:
+                               isc_buffer_forward(&optbuf, optlen);
+                               break;
+                       }
+               }
+       }
+
+       isc_stats_increment(ns_g_server->nsstats, dns_nsstatscounter_edns0in);
+
+       /*
+        * Create an OPT for our reply.
+        */
+       result = client_addopt(client);
+       if (result != ISC_R_SUCCESS) {
+               ns_client_error(client, result);
+               goto cleanup;
+       }
+ cleanup:
+       return (result);
+}
+
 /*
  * Handle an incoming request event from the socket (UDP case)
  * or tcpmsg (TCP case).
@@ -1367,8 +1392,6 @@ client_request(isc_task_t *task, isc_event_t *event) {
        dns_messageid_t id;
        unsigned int flags;
        isc_boolean_t notimp;
-       dns_rdata_t rdata;
-       isc_uint16_t optcode;
 
        REQUIRE(event != NULL);
        client = event->ev_arg;
@@ -1568,67 +1591,9 @@ client_request(isc_task_t *task, isc_event_t *event) {
         */
        opt = dns_message_getopt(client->message);
        if (opt != NULL) {
-               /*
-                * Set the client's UDP buffer size.
-                */
-               client->udpsize = opt->rdclass;
-
-               /*
-                * If the requested UDP buffer size is less than 512,
-                * ignore it and use 512.
-                */
-               if (client->udpsize < 512)
-                       client->udpsize = 512;
-
-               /*
-                * Get the flags out of the OPT record.
-                */
-               client->extflags = (isc_uint16_t)(opt->ttl & 0xFFFF);
-
-               /*
-                * Do we understand this version of EDNS?
-                *
-                * XXXRTH need library support for this!
-                */
-               client->ednsversion = (opt->ttl & 0x00FF0000) >> 16;
-               if (client->ednsversion > 0) {
-                       isc_stats_increment(ns_g_server->nsstats,
-                                           dns_nsstatscounter_badednsver);
-                       result = client_addopt(client);
-                       if (result == ISC_R_SUCCESS)
-                               result = DNS_R_BADVERS;
-                       ns_client_error(client, result);
-                       goto cleanup;
-               }
-
-               /* Check for NSID request */
-               result = dns_rdataset_first(opt);
-               if (result == ISC_R_SUCCESS) {
-                       dns_rdata_init(&rdata);
-                       dns_rdataset_current(opt, &rdata);
-                       if (rdata.length >= 2) {
-                               isc_buffer_t nsidbuf;
-                               isc_buffer_init(&nsidbuf,
-                                               rdata.data, rdata.length);
-                               isc_buffer_add(&nsidbuf, rdata.length);
-                               optcode = isc_buffer_getuint16(&nsidbuf);
-                               if (optcode == DNS_OPT_NSID)
-                                       client->attributes |=
-                                               NS_CLIENTATTR_WANTNSID;
-                       }
-               }
-
-               isc_stats_increment(ns_g_server->nsstats,
-                                   dns_nsstatscounter_edns0in);
-
-               /*
-                * Create an OPT for our reply.
-                */
-               result = client_addopt(client);
-               if (result != ISC_R_SUCCESS) {
-                       ns_client_error(client, result);
+               result = process_opt(client, opt);
+               if (result != ISC_R_SUCCESS)
                        goto cleanup;
-               }
        }
 
        if (client->message->rdclass == 0) {