Exclude EDE before other EDNS options when there isn't enough space

diff --git a/util/data/msgencode.c b/util/data/msgencode.c
index fe21cfb86bd11a46ef1b0a319f68d406bd340527..c394cceba989f109764a072244979d0a17d84d53 100644 (file)
--- a/util/data/msgencode.c
+++ b/util/data/msgencode.c
@@ -806,6 +806,24 @@ calc_edns_field_size(struct edns_data* edns)
        return 1 + 2 + 2 + 4 + 2 + rdatalen;
 }
 
+uint16_t
+calc_edns_option_size(struct edns_data* edns, uint16_t code)
+{
+       size_t rdatalen = 0;
+       struct edns_option* opt;
+       if(!edns || !edns->edns_present)
+               return 0;
+       for(opt = edns->opt_list_inplace_cb_out; opt; opt = opt->next) {
+               if (opt->opt_code == code)
+                       rdatalen += 4 + opt->opt_len;
+       }
+       for(opt = edns->opt_list_out; opt; opt = opt->next) {
+               if (opt->opt_code == code)
+                       rdatalen += 4 + opt->opt_len;
+       }
+       return rdatalen;
+}
+
 static void
 attach_edns_record_max_msg_sz(sldns_buffer* pkt, struct edns_data* edns,
        uint16_t max_msg_sz)
@@ -918,23 +936,30 @@ reply_info_answer_encode(struct query_info* qinf, struct reply_info* rep,
                return 0;
        if(sldns_buffer_capacity(pkt) < udpsize)
                udpsize = sldns_buffer_capacity(pkt);
-       if(udpsize < LDNS_HEADER_SIZE + calc_edns_field_size(edns)) {
+       if(udpsize < LDNS_HEADER_SIZE + calc_edns_field_size(edns) -
+               calc_edns_option_size(edns, LDNS_EDNS_EDE)) {
                /* packet too small to contain edns, omit it. */
                attach_edns = 0;
        } else {
                /* reserve space for edns record */
-               attach_edns = (unsigned int)calc_edns_field_size(edns);
-               udpsize -= attach_edns;
+               attach_edns = (unsigned int)calc_edns_field_size(edns) -
+                       calc_edns_option_size(edns, LDNS_EDNS_EDE);
        }
 
        if(!reply_info_encode(qinf, rep, id, flags, pkt, timenow, region,
-               udpsize, dnssec, MINIMAL_RESPONSES)) {
+               udpsize - attach_edns, dnssec, MINIMAL_RESPONSES)) {
                log_err("reply encode: out of memory");
                return 0;
        }
-       if(attach_edns && sldns_buffer_capacity(pkt) >=
-               sldns_buffer_limit(pkt)+attach_edns)
-               attach_edns_record_max_msg_sz(pkt, edns, udpsize+attach_edns);
+       if(attach_edns) {
+               if(udpsize >= sldns_buffer_limit(pkt)+calc_edns_field_size(edns))
+                       attach_edns_record_max_msg_sz(pkt, edns, udpsize);
+               else if(udpsize >= sldns_buffer_limit(pkt) + attach_edns) {
+                       edns_opt_list_remove(&edns->opt_list_inplace_cb_out, LDNS_EDNS_EDE);
+                       edns_opt_list_remove(&edns->opt_list_out, LDNS_EDNS_EDE);
+                       attach_edns_record_max_msg_sz(pkt, edns, udpsize);
+               }
+       }
        return 1;
 }
 
@@ -996,8 +1021,14 @@ error_encode(sldns_buffer* buf, int r, struct query_info* qinfo,
                es.ext_rcode = 0;
                es.bits &= EDNS_DO;
                if(sldns_buffer_limit(buf) + calc_edns_field_size(&es) >
-                       edns->udp_size)
-                       return;
+                       edns->udp_size) {
+                       edns_opt_list_remove(&es.opt_list_inplace_cb_out, LDNS_EDNS_EDE);
+                       edns_opt_list_remove(&es.opt_list_out, LDNS_EDNS_EDE);
+                       if(sldns_buffer_limit(buf) + calc_edns_field_size(&es) >
+                               edns->udp_size) {
+                               return;
+                       }
+               }
                attach_edns_record(buf, &es);
        }
 }

diff --git a/util/data/msgencode.h b/util/data/msgencode.h
index 30dc515cbe595eadcb0bf58b5ded21b32e55296c..7dd1772ddd8bcb3fbaa232359812558e146846ad 100644 (file)
--- a/util/data/msgencode.h
+++ b/util/data/msgencode.h
@@ -108,6 +108,14 @@ void qinfo_query_encode(struct sldns_buffer* pkt, struct query_info* qinfo);
  */
 uint16_t calc_edns_field_size(struct edns_data* edns);
 
+/**
+ * Calculate the size of a specific EDNS option in packet.
+ * @param edns: edns data or NULL.
+ * @param code: the opt code to get the size of.
+ * @return octets the option will take up.
+ */
+uint16_t calc_edns_option_size(struct edns_data* edns, uint16_t code);
+
 /**
  * Attach EDNS record to buffer. Buffer has complete packet. There must
  * be enough room left for the EDNS record.