1 files changed, 42 insertions, 10 deletions

diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c
index 14faf9e4ab..5f79701296 100644
--- a/src/resolve/resolved-dns-packet.c
+++ b/src/resolve/resolved-dns-packet.c
@@ -58,6 +58,7 @@ int dns_packet_new(DnsPacket **ret, DnsProtocol protocol, size_t mtu) {
         p->size = p->rindex = DNS_PACKET_HEADER_SIZE;
         p->allocated = a;
         p->protocol = protocol;
+        p->opt_start = p->opt_size = (size_t) -1;
         p->n_ref = 1;
 
         *ret = p;
@@ -499,7 +500,7 @@ int dns_packet_append_name(
         saved_size = p->size;
 
         while (*name) {
-                _cleanup_free_ char *s = NULL;
+                const char *z = name;
                 char label[DNS_LABEL_MAX];
                 size_t n = 0;
                 int k;
@@ -518,12 +519,6 @@ int dns_packet_append_name(
                         }
                 }
 
-                s = strdup(name);
-                if (!s) {
-                        r = -ENOMEM;
-                        goto fail;
-                }
-
                 r = dns_label_unescape(&name, label, sizeof(label));
                 if (r < 0)
                         goto fail;
@@ -544,6 +539,14 @@ int dns_packet_append_name(
                         goto fail;
 
                 if (allow_compression) {
+                        _cleanup_free_ char *s = NULL;
+
+                        s = strdup(z);
+                        if (!s) {
+                                r = -ENOMEM;
+                                goto fail;
+                        }
+
                         r = hashmap_ensure_allocated(&p->names, &dns_name_hash_ops);
                         if (r < 0)
                                 goto fail;
@@ -643,7 +646,6 @@ static int dns_packet_append_types(DnsPacket *p, Bitmap *types, size_t *start) {
         int r;
 
         assert(p);
-        assert(types);
 
         saved_size = p->size;
 
@@ -680,7 +682,7 @@ fail:
 }
 
 /* Append the OPT pseudo-RR described in RFC6891 */
-int dns_packet_append_opt_rr(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, size_t *start) {
+int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, size_t *start) {
         size_t saved_size;
         int r;
 
@@ -688,6 +690,11 @@ int dns_packet_append_opt_rr(DnsPacket *p, uint16_t max_udp_size, bool edns0_do,
         /* we must never advertise supported packet size smaller than the legacy max */
         assert(max_udp_size >= DNS_PACKET_UNICAST_SIZE_MAX);
 
+        if (p->opt_start != (size_t) -1)
+                return -EBUSY;
+
+        assert(p->opt_size == (size_t) -1);
+
         saved_size = p->size;
 
         /* empty name */
@@ -720,6 +727,11 @@ int dns_packet_append_opt_rr(DnsPacket *p, uint16_t max_udp_size, bool edns0_do,
         if (r < 0)
                 goto fail;
 
+        DNS_PACKET_HEADER(p)->arcount = htobe16(DNS_PACKET_ARCOUNT(p) + 1);
+
+        p->opt_start = saved_size;
+        p->opt_size = p->size - saved_size;
+
         if (start)
                 *start = saved_size;
 
@@ -730,6 +742,27 @@ fail:
         return r;
 }
 
+int dns_packet_truncate_opt(DnsPacket *p) {
+        assert(p);
+
+        if (p->opt_start == (size_t) -1) {
+                assert(p->opt_size == (size_t) -1);
+                return 0;
+        }
+
+        assert(p->opt_size != (size_t) -1);
+        assert(DNS_PACKET_ARCOUNT(p) > 0);
+
+        if (p->opt_start + p->opt_size != p->size)
+                return -EBUSY;
+
+        dns_packet_truncate(p, p->opt_start);
+        DNS_PACKET_HEADER(p)->arcount = htobe16(DNS_PACKET_ARCOUNT(p) - 1);
+        p->opt_start = p->opt_size = (size_t) -1;
+
+        return 1;
+}
+
 int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start, size_t *rdata_start) {
         size_t saved_size, rdlength_offset, end, rdlength, rds;
         int r;
@@ -1045,7 +1078,6 @@ fail:
         return r;
 }
 
-
 int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start) {
         assert(p);