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-rw-r--r--lib/cache/knot_pkt.c94
1 files changed, 94 insertions, 0 deletions
diff --git a/lib/cache/knot_pkt.c b/lib/cache/knot_pkt.c
new file mode 100644
index 0000000..31fa7e9
--- /dev/null
+++ b/lib/cache/knot_pkt.c
@@ -0,0 +1,94 @@
+/* Copyright (C) CZ.NIC, z.s.p.o. <knot-resolver@labs.nic.cz>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+/** @file
+ * Implementation of preparing knot_pkt_t for filling with RRs.
+ * Prototypes in ./impl.h
+ */
+
+#include "lib/cache/impl.h"
+
+int pkt_renew(knot_pkt_t *pkt, const knot_dname_t *name, uint16_t type)
+{
+ /* Update packet question if needed. */
+ if (!knot_dname_is_equal(knot_pkt_qname(pkt), name)
+ || knot_pkt_qtype(pkt) != type || knot_pkt_qclass(pkt) != KNOT_CLASS_IN) {
+ int ret = kr_pkt_recycle(pkt);
+ if (ret) return kr_error(ret);
+ ret = knot_pkt_put_question(pkt, name, KNOT_CLASS_IN, type);
+ if (ret) return kr_error(ret);
+ }
+
+ pkt->parsed = pkt->size = KR_PKT_SIZE_NOWIRE;
+ knot_wire_set_qr(pkt->wire);
+ knot_wire_set_aa(pkt->wire);
+ return kr_ok();
+}
+
+/** Reserve space for additional `count` RRsets.
+ * \note pkt->rr_info gets correct length but is always zeroed
+ */
+static int pkt_alloc_space(knot_pkt_t *pkt, int count)
+{
+ size_t allocd_orig = pkt->rrset_allocd;
+ if (pkt->rrset_count + count <= allocd_orig) {
+ return kr_ok();
+ }
+ /* A simple growth strategy, amortized O(count). */
+ pkt->rrset_allocd = MAX(
+ pkt->rrset_count + count,
+ pkt->rrset_count + allocd_orig);
+
+ pkt->rr = mm_realloc(&pkt->mm, pkt->rr,
+ sizeof(pkt->rr[0]) * pkt->rrset_allocd,
+ sizeof(pkt->rr[0]) * allocd_orig);
+ if (!pkt->rr) {
+ return kr_error(ENOMEM);
+ }
+ /* Allocate pkt->rr_info to be certain, but just leave it zeroed. */
+ mm_free(&pkt->mm, pkt->rr_info);
+ pkt->rr_info = mm_calloc(&pkt->mm, pkt->rrset_allocd, sizeof(pkt->rr_info[0]));
+ if (!pkt->rr_info) {
+ return kr_error(ENOMEM);
+ }
+ return kr_ok();
+}
+
+int pkt_append(knot_pkt_t *pkt, const struct answer_rrset *rrset, uint8_t rank)
+{
+ /* allocate space, to be sure */
+ int rrset_cnt = (rrset->set.rr->rrs.count > 0) + (rrset->sig_rds.count > 0);
+ int ret = pkt_alloc_space(pkt, rrset_cnt);
+ if (ret) return kr_error(ret);
+ /* write both sets */
+ const knot_rdataset_t *rdss[2] = { &rrset->set.rr->rrs, &rrset->sig_rds };
+ for (int i = 0; i < rrset_cnt; ++i) {
+ if (kr_fails_assert(rdss[i]->count))
+ return kr_error(EINVAL);
+ /* allocate rank */
+ uint8_t *rr_rank = mm_alloc(&pkt->mm, sizeof(*rr_rank));
+ if (!rr_rank) return kr_error(ENOMEM);
+ *rr_rank = (i == 0) ? rank : (KR_RANK_OMIT | KR_RANK_AUTH);
+ /* rank for RRSIGs isn't really useful: ^^ */
+ if (i == 0) {
+ pkt->rr[pkt->rrset_count] = *rrset->set.rr;
+ pkt->rr[pkt->rrset_count].additional = rr_rank;
+ } else {
+ /* append the RR array */
+ pkt->rr[pkt->rrset_count] = (knot_rrset_t){
+ .owner = knot_dname_copy(rrset->set.rr->owner, &pkt->mm),
+ /* ^^ well, another copy isn't really needed */
+ .ttl = rrset->set.rr->ttl,
+ .type = KNOT_RRTYPE_RRSIG,
+ .rclass = KNOT_CLASS_IN,
+ .rrs = *rdss[i],
+ .additional = rr_rank,
+ };
+ }
+ ++pkt->rrset_count;
+ ++(pkt->sections[pkt->current].count);
+ }
+ return kr_ok();
+}
+