1b7d3089d5
- Fix for losing nameserver when it drops UDP fragments in ldns_resolver_send_pkt [Willem Toorop <willem@NLnetLabs.nl>] - Added ldnsx module (to be merged into ldns soon) http://git.xelerance.com/cgi-bin/gitweb.cgi?p=ldnsx.git;a=summary
71 lines
1.9 KiB
Diff
71 lines
1.9 KiB
Diff
Index: resolver.c
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===================================================================
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--- resolver.c (revision 3550)
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+++ resolver.c (revision 3551)
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@@ -1031,12 +1031,41 @@
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return pkt;
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}
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+static size_t *
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+ldns_resolver_backup_rtt(ldns_resolver *r)
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+{
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+ size_t *new_rtt;
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+ size_t *old_rtt = ldns_resolver_rtt(r);
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+
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+ if (old_rtt && ldns_resolver_nameserver_count(r)) {
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+ new_rtt = LDNS_XMALLOC(size_t
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+ , ldns_resolver_nameserver_count(r));
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+ memcpy(new_rtt, old_rtt, sizeof(size_t)
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+ * ldns_resolver_nameserver_count(r));
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+ ldns_resolver_set_rtt(r, new_rtt);
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+ return old_rtt;
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+ }
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+ return NULL;
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+}
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+
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+static void
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+ldns_resolver_restore_rtt(ldns_resolver *r, size_t *old_rtt)
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+{
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+ size_t *cur_rtt = ldns_resolver_rtt(r);
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+
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+ if (cur_rtt) {
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+ LDNS_FREE(cur_rtt);
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+ }
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+ ldns_resolver_set_rtt(r, old_rtt);
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+}
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+
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ldns_status
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ldns_resolver_send_pkt(ldns_pkt **answer, ldns_resolver *r,
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ldns_pkt *query_pkt)
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{
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ldns_pkt *answer_pkt = NULL;
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ldns_status stat = LDNS_STATUS_OK;
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+ size_t *rtt;
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stat = ldns_send(&answer_pkt, (ldns_resolver *)r, query_pkt);
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if (stat != LDNS_STATUS_OK) {
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@@ -1051,9 +1080,21 @@
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if (ldns_pkt_tc(answer_pkt)) {
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/* was EDNS0 set? */
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if (ldns_pkt_edns_udp_size(query_pkt) == 0) {
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- ldns_pkt_set_edns_udp_size(query_pkt, 4096);
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+ ldns_pkt_set_edns_udp_size(query_pkt
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+ , 4096);
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ldns_pkt_free(answer_pkt);
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- stat = ldns_send(&answer_pkt, r, query_pkt);
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+ /* Nameservers should not become
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+ * unreachable because fragments are
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+ * dropped (network error). We might
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+ * still have success with TCP.
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+ * Therefore maintain reachability
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+ * statuses of the nameservers by
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+ * backup and restore the rtt list.
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+ */
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+ rtt = ldns_resolver_backup_rtt(r);
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+ stat = ldns_send(&answer_pkt, r
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+ , query_pkt);
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+ ldns_resolver_restore_rtt(r, rtt);
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}
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/* either way, if it is still truncated, use TCP */
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if (stat != LDNS_STATUS_OK ||
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