Merge pull request #2589 from keszybz/resolve-tool-2

Better support of OPENPGPKEY, CAA, TLSA packets and tests

18 files changed, 451 insertions, 285 deletions

diff --git a/src/resolve/dns-type.h b/src/resolve/dns-type.h
index a6c1630021..f18ac6eef3 100644
--- a/src/resolve/dns-type.h
+++ b/src/resolve/dns-type.h
@@ -152,3 +152,6 @@ const char *tlsa_selector_to_string(uint8_t selector);
 
 /* https://tools.ietf.org/html/draft-ietf-dane-protocol-23#section-7.4 */
 const char *tlsa_matching_type_to_string(uint8_t selector);
+
+/* https://tools.ietf.org/html/rfc6844#section-5.1 */
+#define CAA_FLAG_CRITICAL (1u << 7)
diff --git a/src/resolve/resolve-tool.c b/src/resolve/resolve-tool.c
index 824cb267b5..9aade8e490 100644
--- a/src/resolve/resolve-tool.c
+++ b/src/resolve/resolve-tool.c
@@ -17,6 +17,7 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+#include <gcrypt.h>
 #include <getopt.h>
 #include <net/if.h>
 
@@ -28,6 +29,7 @@
 #include "bus-util.h"
 #include "escape.h"
 #include "in-addr-util.h"
+#include "gcrypt-util.h"
 #include "parse-util.h"
 #include "resolved-def.h"
 #include "resolved-dns-packet.h"
@@ -46,6 +48,7 @@ static enum {
         MODE_RESOLVE_HOST,
         MODE_RESOLVE_RECORD,
         MODE_RESOLVE_SERVICE,
+        MODE_RESOLVE_OPENPGP,
         MODE_STATISTICS,
         MODE_RESET_STATISTICS,
 } arg_mode = MODE_RESOLVE_HOST;
@@ -545,15 +548,10 @@ static int resolve_rfc4501(sd_bus *bus, const char *name) {
         } else
                 n = p;
 
-        if (type == 0)
-                type = arg_type;
-        if (type == 0)
-                type = DNS_TYPE_A;
-
         if (class == 0)
-                class = arg_class;
-        if (class == 0)
-                class = DNS_CLASS_IN;
+                class = arg_class ?: DNS_CLASS_IN;
+        if (type == 0)
+                type = arg_type ?: DNS_TYPE_A;
 
         return resolve_record(bus, n, class, type);
 
@@ -763,6 +761,36 @@ static int resolve_service(sd_bus *bus, const char *name, const char *type, cons
         return 0;
 }
 
+static int resolve_openpgp(sd_bus *bus, const char *address) {
+        const char *domain, *full;
+        int r;
+        _cleanup_free_ char *hashed = NULL;
+
+        assert(bus);
+        assert(address);
+
+        domain = strrchr(address, '@');
+        if (!domain) {
+                log_error("Address does not contain '@': \"%s\"", address);
+                return -EINVAL;
+        } else if (domain == address || domain[1] == '\0') {
+                log_error("Address starts or ends with '@': \"%s\"", address);
+                return -EINVAL;
+        }
+        domain++;
+
+        r = string_hashsum(address, domain - 1 - address, GCRY_MD_SHA224, &hashed);
+        if (r < 0)
+                return log_error_errno(r, "Hashing failed: %m");
+
+        full = strjoina(hashed, "._openpgpkey.", domain);
+        log_debug("Looking up \"%s\".", full);
+
+        return resolve_record(bus, full,
+                              arg_class ?: DNS_CLASS_IN,
+                              arg_type ?: DNS_TYPE_OPENPGPKEY);
+}
+
 static int show_statistics(sd_bus *bus) {
         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
         _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
@@ -945,6 +973,7 @@ static void help(void) {
                "     --service                Resolve service (SRV)\n"
                "     --service-address=BOOL   Do [not] resolve address for services\n"
                "     --service-txt=BOOL       Do [not] resolve TXT records for services\n"
+               "     --openpgp                Query OpenPGP public key\n"
                "     --cname=BOOL             Do [not] follow CNAME redirects\n"
                "     --search=BOOL            Do [not] use search domains\n"
                "     --legend=BOOL            Do [not] print column headers and meta information\n"
@@ -961,6 +990,7 @@ static int parse_argv(int argc, char *argv[]) {
                 ARG_CNAME,
                 ARG_SERVICE_ADDRESS,
                 ARG_SERVICE_TXT,
+                ARG_OPENPGP,
                 ARG_SEARCH,
                 ARG_STATISTICS,
                 ARG_RESET_STATISTICS,
@@ -978,6 +1008,7 @@ static int parse_argv(int argc, char *argv[]) {
                 { "service",          no_argument,       NULL, ARG_SERVICE          },
                 { "service-address",  required_argument, NULL, ARG_SERVICE_ADDRESS  },
                 { "service-txt",      required_argument, NULL, ARG_SERVICE_TXT      },
+                { "openpgp",          no_argument,       NULL, ARG_OPENPGP          },
                 { "search",           required_argument, NULL, ARG_SEARCH           },
                 { "statistics",       no_argument,       NULL, ARG_STATISTICS,      },
                 { "reset-statistics", no_argument,       NULL, ARG_RESET_STATISTICS },
@@ -1087,6 +1118,10 @@ static int parse_argv(int argc, char *argv[]) {
                         arg_mode = MODE_RESOLVE_SERVICE;
                         break;
 
+                case ARG_OPENPGP:
+                        arg_mode = MODE_RESOLVE_OPENPGP;
+                        break;
+
                 case ARG_CNAME:
                         r = parse_boolean(optarg);
                         if (r < 0)
@@ -1246,6 +1281,24 @@ int main(int argc, char **argv) {
 
                 break;
 
+        case MODE_RESOLVE_OPENPGP:
+                if (argc < optind + 1) {
+                        log_error("E-mail address required.");
+                        r = -EINVAL;
+                        goto finish;
+
+                }
+
+                r = 0;
+                while (optind < argc) {
+                        int k;
+
+                        k = resolve_openpgp(bus, argv[optind++]);
+                        if (k < 0)
+                                r = k;
+                }
+                break;
+
         case MODE_STATISTICS:
                 if (argc > optind) {
                         log_error("Too many arguments.");
diff --git a/src/resolve/resolved-dns-dnssec.c b/src/resolve/resolved-dns-dnssec.c
index 7aea9cb653..7098265929 100644
--- a/src/resolve/resolved-dns-dnssec.c
+++ b/src/resolve/resolved-dns-dnssec.c
@@ -23,6 +23,7 @@
 
 #include "alloc-util.h"
 #include "dns-domain.h"
+#include "gcrypt-util.h"
 #include "hexdecoct.h"
 #include "resolved-dns-dnssec.h"
 #include "resolved-dns-packet.h"
@@ -126,19 +127,6 @@ int dnssec_canonicalize(const char *n, char *buffer, size_t buffer_max) {
 
 #ifdef HAVE_GCRYPT
 
-static void initialize_libgcrypt(void) {
-        const char *p;
-
-        if (gcry_control(GCRYCTL_INITIALIZATION_FINISHED_P))
-                return;
-
-        p = gcry_check_version("1.4.5");
-        assert(p);
-
-        gcry_control(GCRYCTL_DISABLE_SECMEM);
-        gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
-}
-
 static int rr_compare(const void *a, const void *b) {
         DnsResourceRecord **x = (DnsResourceRecord**) a, **y = (DnsResourceRecord**) b;
         size_t m;
@@ -737,7 +725,7 @@ int dnssec_verify_rrset(
         qsort_safe(list, n, sizeof(DnsResourceRecord*), rr_compare);
 
         /* OK, the RRs are now in canonical order. Let's calculate the digest */
-        initialize_libgcrypt();
+        initialize_libgcrypt(false);
 
         hash_size = gcry_md_get_algo_dlen(md_algorithm);
         assert(hash_size > 0);
@@ -1070,7 +1058,7 @@ int dnssec_verify_dnskey_by_ds(DnsResourceRecord *dnskey, DnsResourceRecord *ds,
         if (dnssec_keytag(dnskey, mask_revoke) != ds->ds.key_tag)
                 return 0;
 
-        initialize_libgcrypt();
+        initialize_libgcrypt(false);
 
         md_algorithm = digest_to_gcrypt_md(ds->ds.digest_type);
         if (md_algorithm < 0)
@@ -1189,7 +1177,7 @@ int dnssec_nsec3_hash(DnsResourceRecord *nsec3, const char *name, void *ret) {
         if (algorithm < 0)
                 return algorithm;
 
-        initialize_libgcrypt();
+        initialize_libgcrypt(false);
 
         hash_size = gcry_md_get_algo_dlen(algorithm);
         assert(hash_size > 0);
diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c
index c940dd8929..c2fc1d8b05 100644
--- a/src/resolve/resolved-dns-packet.c
+++ b/src/resolve/resolved-dns-packet.c
@@ -28,6 +28,19 @@
 
 #define EDNS0_OPT_DO (1<<15)
 
+typedef struct DnsPacketRewinder {
+        DnsPacket *packet;
+        size_t saved_rindex;
+} DnsPacketRewinder;
+
+static void rewind_dns_packet(DnsPacketRewinder *rewinder) {
+        if (rewinder->packet)
+                dns_packet_rewind(rewinder->packet, rewinder->saved_rindex);
+}
+
+#define INIT_REWINDER(rewinder, p) do { rewinder.packet = p; rewinder.saved_rindex = p->rindex; } while(0)
+#define CANCEL_REWINDER(rewinder) do { rewinder.packet = NULL; } while(0)
+
 int dns_packet_new(DnsPacket **ret, DnsProtocol protocol, size_t mtu) {
         DnsPacket *p;
         size_t a;
@@ -431,8 +444,7 @@ int dns_packet_append_raw_string(DnsPacket *p, const void *s, size_t size, size_
 
         ((uint8_t*) d)[0] = (uint8_t) size;
 
-        if (size > 0)
-                memcpy(((uint8_t*) d) + 1, s, size);
+        memcpy_safe(((uint8_t*) d) + 1, s, size);
 
         return 0;
 }
@@ -1072,6 +1084,18 @@ int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *star
                 r = dns_packet_append_blob(p, rr->tlsa.data, rr->tlsa.data_size, NULL);
                 break;
 
+        case DNS_TYPE_CAA:
+                r = dns_packet_append_uint8(p, rr->caa.flags, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_string(p, rr->caa.tag, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_blob(p, rr->caa.value, rr->caa.value_size, NULL);
+                break;
+
         case DNS_TYPE_OPT:
         case DNS_TYPE_OPENPGPKEY:
         case _DNS_TYPE_INVALID: /* unparseable */
@@ -1230,80 +1254,67 @@ int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start) {
 }
 
 int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start) {
-        size_t saved_rindex;
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
         const void *d;
         char *t;
         uint8_t c;
         int r;
 
         assert(p);
-
-        saved_rindex = p->rindex;
+        INIT_REWINDER(rewinder, p);
 
         r = dns_packet_read_uint8(p, &c, NULL);
         if (r < 0)
-                goto fail;
+                return r;
 
         r = dns_packet_read(p, c, &d, NULL);
         if (r < 0)
-                goto fail;
+                return r;
 
-        if (memchr(d, 0, c)) {
-                r = -EBADMSG;
-                goto fail;
-        }
+        if (memchr(d, 0, c))
+                return -EBADMSG;
 
         t = strndup(d, c);
-        if (!t) {
-                r = -ENOMEM;
-                goto fail;
-        }
+        if (!t)
+                return -ENOMEM;
 
         if (!utf8_is_valid(t)) {
                 free(t);
-                r = -EBADMSG;
-                goto fail;
+                return -EBADMSG;
         }
 
         *ret = t;
 
         if (start)
-                *start = saved_rindex;
+                *start = rewinder.saved_rindex;
+        CANCEL_REWINDER(rewinder);
 
         return 0;
-
-fail:
-        dns_packet_rewind(p, saved_rindex);
-        return r;
 }
 
 int dns_packet_read_raw_string(DnsPacket *p, const void **ret, size_t *size, size_t *start) {
-        size_t saved_rindex;
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
         uint8_t c;
         int r;
 
         assert(p);
-
-        saved_rindex = p->rindex;
+        INIT_REWINDER(rewinder, p);
 
         r = dns_packet_read_uint8(p, &c, NULL);
         if (r < 0)
-                goto fail;
+                return r;
 
         r = dns_packet_read(p, c, ret, NULL);
         if (r < 0)
-                goto fail;
+                return r;
 
         if (size)
                 *size = c;
         if (start)
-                *start = saved_rindex;
+                *start = rewinder.saved_rindex;
+        CANCEL_REWINDER(rewinder);
 
         return 0;
-
-fail:
-        dns_packet_rewind(p, saved_rindex);
-        return r;
 }
 
 int dns_packet_read_name(
@@ -1312,7 +1323,8 @@ int dns_packet_read_name(
                 bool allow_compression,
                 size_t *start) {
 
-        size_t saved_rindex, after_rindex = 0, jump_barrier;
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
+        size_t after_rindex = 0, jump_barrier;
         _cleanup_free_ char *ret = NULL;
         size_t n = 0, allocated = 0;
         bool first = true;
@@ -1320,19 +1332,18 @@ int dns_packet_read_name(
 
         assert(p);
         assert(_ret);
+        INIT_REWINDER(rewinder, p);
+        jump_barrier = p->rindex;
 
         if (p->refuse_compression)
                 allow_compression = false;
 
-        saved_rindex = p->rindex;
-        jump_barrier = p->rindex;
-
         for (;;) {
                 uint8_t c, d;
 
                 r = dns_packet_read_uint8(p, &c, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 if (c == 0)
                         /* End of name */
@@ -1343,12 +1354,10 @@ int dns_packet_read_name(
                         /* Literal label */
                         r = dns_packet_read(p, c, (const void**) &label, NULL);
                         if (r < 0)
-                                goto fail;
+                                return r;
 
-                        if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX)) {
-                                r = -ENOMEM;
-                                goto fail;
-                        }
+                        if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX))
+                                return -ENOMEM;
 
                         if (first)
                                 first = false;
@@ -1357,7 +1366,7 @@ int dns_packet_read_name(
 
                         r = dns_label_escape(label, c, ret + n, DNS_LABEL_ESCAPED_MAX);
                         if (r < 0)
-                                goto fail;
+                                return r;
 
                         n += r;
                         continue;
@@ -1367,13 +1376,11 @@ int dns_packet_read_name(
                         /* Pointer */
                         r = dns_packet_read_uint8(p, &d, NULL);
                         if (r < 0)
-                                goto fail;
+                                return r;
 
                         ptr = (uint16_t) (c & ~0xc0) << 8 | (uint16_t) d;
-                        if (ptr < DNS_PACKET_HEADER_SIZE || ptr >= jump_barrier) {
-                                r = -EBADMSG;
-                                goto fail;
-                        }
+                        if (ptr < DNS_PACKET_HEADER_SIZE || ptr >= jump_barrier)
+                                return -EBADMSG;
 
                         if (after_rindex == 0)
                                 after_rindex = p->rindex;
@@ -1381,16 +1388,12 @@ int dns_packet_read_name(
                         /* Jumps are limited to a "prior occurrence" (RFC-1035 4.1.4) */
                         jump_barrier = ptr;
                         p->rindex = ptr;
-                } else {
-                        r = -EBADMSG;
-                        goto fail;
-                }
+                } else
+                        return -EBADMSG;
         }
 
-        if (!GREEDY_REALLOC(ret, allocated, n + 1)) {
-                r = -ENOMEM;
-                goto fail;
-        }
+        if (!GREEDY_REALLOC(ret, allocated, n + 1))
+                return -ENOMEM;
 
         ret[n] = 0;
 
@@ -1401,13 +1404,10 @@ int dns_packet_read_name(
         ret = NULL;
 
         if (start)
-                *start = saved_rindex;
+                *start = rewinder.saved_rindex;
+        CANCEL_REWINDER(rewinder);
 
         return 0;
-
-fail:
-        dns_packet_rewind(p, saved_rindex);
-        return r;
 }
 
 static int dns_packet_read_type_window(DnsPacket *p, Bitmap **types, size_t *start) {
@@ -1417,32 +1417,31 @@ static int dns_packet_read_type_window(DnsPacket *p, Bitmap **types, size_t *sta
         uint8_t bit = 0;
         unsigned i;
         bool found = false;
-        size_t saved_rindex;
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
         int r;
 
         assert(p);
         assert(types);
-
-        saved_rindex = p->rindex;
+        INIT_REWINDER(rewinder, p);
 
         r = bitmap_ensure_allocated(types);
         if (r < 0)
-                goto fail;
+                return r;
 
         r = dns_packet_read_uint8(p, &window, NULL);
         if (r < 0)
-                goto fail;
+                return r;
 
         r = dns_packet_read_uint8(p, &length, NULL);
         if (r < 0)
-                goto fail;
+                return r;
 
         if (length == 0 || length > 32)
                 return -EBADMSG;
 
         r = dns_packet_read(p, length, (const void **)&bitmap, NULL);
         if (r < 0)
-                goto fail;
+                return r;
 
         for (i = 0; i < length; i++) {
                 uint8_t bitmask = 1 << 7;
@@ -1467,7 +1466,7 @@ static int dns_packet_read_type_window(DnsPacket *p, Bitmap **types, size_t *sta
 
                                 r = bitmap_set(*types, n);
                                 if (r < 0)
-                                        goto fail;
+                                        return r;
                         }
 
                         bit ++;
@@ -1479,70 +1478,61 @@ static int dns_packet_read_type_window(DnsPacket *p, Bitmap **types, size_t *sta
                 return -EBADMSG;
 
         if (start)
-                *start = saved_rindex;
+                *start = rewinder.saved_rindex;
+        CANCEL_REWINDER(rewinder);
 
         return 0;
-fail:
-        dns_packet_rewind(p, saved_rindex);
-        return r;
 }
 
 static int dns_packet_read_type_windows(DnsPacket *p, Bitmap **types, size_t size, size_t *start) {
-        size_t saved_rindex;
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
         int r;
 
-        saved_rindex = p->rindex;
+        INIT_REWINDER(rewinder, p);
 
-        while (p->rindex < saved_rindex + size) {
+        while (p->rindex < rewinder.saved_rindex + size) {
                 r = dns_packet_read_type_window(p, types, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 /* don't read past end of current RR */
-                if (p->rindex > saved_rindex + size) {
-                        r = -EBADMSG;
-                        goto fail;
-                }
+                if (p->rindex > rewinder.saved_rindex + size)
+                        return -EBADMSG;
         }
 
-        if (p->rindex != saved_rindex + size) {
-                r = -EBADMSG;
-                goto fail;
-        }
+        if (p->rindex != rewinder.saved_rindex + size)
+                return -EBADMSG;
 
         if (start)
-                *start = saved_rindex;
+                *start = rewinder.saved_rindex;
+        CANCEL_REWINDER(rewinder);
 
         return 0;
-fail:
-        dns_packet_rewind(p, saved_rindex);
-        return r;
 }
 
 int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, bool *ret_cache_flush, size_t *start) {
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
         _cleanup_free_ char *name = NULL;
         bool cache_flush = false;
         uint16_t class, type;
         DnsResourceKey *key;
-        size_t saved_rindex;
         int r;
 
         assert(p);
         assert(ret);
-
-        saved_rindex = p->rindex;
+        INIT_REWINDER(rewinder, p);
 
         r = dns_packet_read_name(p, &name, true, NULL);
         if (r < 0)
-                goto fail;
+                return r;
 
         r = dns_packet_read_uint16(p, &type, NULL);
         if (r < 0)
-                goto fail;
+                return r;
 
         r = dns_packet_read_uint16(p, &class, NULL);
         if (r < 0)
-                goto fail;
+                return r;
 
         if (p->protocol == DNS_PROTOCOL_MDNS) {
                 /* See RFC6762, Section 10.2 */
@@ -1554,10 +1544,8 @@ int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, bool *ret_cache_flus
         }
 
         key = dns_resource_key_new_consume(class, type, name);
-        if (!key) {
-                r = -ENOMEM;
-                goto fail;
-        }
+        if (!key)
+                return -ENOMEM;
 
         name = NULL;
         *ret = key;
@@ -1565,12 +1553,10 @@ int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, bool *ret_cache_flus
         if (ret_cache_flush)
                 *ret_cache_flush = cache_flush;
         if (start)
-                *start = saved_rindex;
+                *start = rewinder.saved_rindex;
+        CANCEL_REWINDER(rewinder);
 
         return 0;
-fail:
-        dns_packet_rewind(p, saved_rindex);
-        return r;
 }
 
 static bool loc_size_ok(uint8_t size) {
@@ -1582,7 +1568,8 @@ static bool loc_size_ok(uint8_t size) {
 int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_flush, size_t *start) {
         _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
         _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
-        size_t saved_rindex, offset;
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
+        size_t offset;
         uint16_t rdlength;
         bool cache_flush;
         int r;
@@ -1590,27 +1577,22 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl
         assert(p);
         assert(ret);
 
-        saved_rindex = p->rindex;
+        INIT_REWINDER(rewinder, p);
 
         r = dns_packet_read_key(p, &key, &cache_flush, NULL);
         if (r < 0)
-                goto fail;
+                return r;
 
-        if (!dns_class_is_valid_rr(key->class)||
-            !dns_type_is_valid_rr(key->type)) {
-                r = -EBADMSG;
-                goto fail;
-        }
+        if (!dns_class_is_valid_rr(key->class) || !dns_type_is_valid_rr(key->type))
+                return -EBADMSG;
 
         rr = dns_resource_record_new(key);
-        if (!rr) {
-                r = -ENOMEM;
-                goto fail;
-        }
+        if (!rr)
+                return -ENOMEM;
 
         r = dns_packet_read_uint32(p, &rr->ttl, NULL);
         if (r < 0)
-                goto fail;
+                return r;
 
         /* RFC 2181, Section 8, suggests to
          * treat a TTL with the MSB set as a zero TTL. */
@@ -1619,12 +1601,10 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl
 
         r = dns_packet_read_uint16(p, &rdlength, NULL);
         if (r < 0)
-                goto fail;
+                return r;
 
-        if (p->rindex + rdlength > p->size) {
-                r = -EBADMSG;
-                goto fail;
-        }
+        if (p->rindex + rdlength > p->size)
+                return -EBADMSG;
 
         offset = p->rindex;
 
@@ -1633,13 +1613,13 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl
         case DNS_TYPE_SRV:
                 r = dns_packet_read_uint16(p, &rr->srv.priority, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
                 r = dns_packet_read_uint16(p, &rr->srv.weight, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
                 r = dns_packet_read_uint16(p, &rr->srv.port, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
                 r = dns_packet_read_name(p, &rr->srv.name, true, NULL);
                 break;
 
@@ -1653,7 +1633,7 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl
         case DNS_TYPE_HINFO:
                 r = dns_packet_read_string(p, &rr->hinfo.cpu, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_string(p, &rr->hinfo.os, NULL);
                 break;
@@ -1709,27 +1689,27 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl
         case DNS_TYPE_SOA:
                 r = dns_packet_read_name(p, &rr->soa.mname, true, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_name(p, &rr->soa.rname, true, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint32(p, &rr->soa.serial, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint32(p, &rr->soa.refresh, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint32(p, &rr->soa.retry, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint32(p, &rr->soa.expire, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint32(p, &rr->soa.minimum, NULL);
                 break;
@@ -1737,7 +1717,7 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl
         case DNS_TYPE_MX:
                 r = dns_packet_read_uint16(p, &rr->mx.priority, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_name(p, &rr->mx.exchange, true, NULL);
                 break;
@@ -1748,49 +1728,43 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl
 
                 r = dns_packet_read_uint8(p, &t, &pos);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 if (t == 0) {
                         rr->loc.version = t;
 
                         r = dns_packet_read_uint8(p, &rr->loc.size, NULL);
                         if (r < 0)
-                                goto fail;
+                                return r;
 
-                        if (!loc_size_ok(rr->loc.size)) {
-                                r = -EBADMSG;
-                                goto fail;
-                        }
+                        if (!loc_size_ok(rr->loc.size))
+                                return -EBADMSG;
 
                         r = dns_packet_read_uint8(p, &rr->loc.horiz_pre, NULL);
                         if (r < 0)
-                                goto fail;
+                                return r;
 
-                        if (!loc_size_ok(rr->loc.horiz_pre)) {
-                                r = -EBADMSG;
-                                goto fail;
-                        }
+                        if (!loc_size_ok(rr->loc.horiz_pre))
+                                return -EBADMSG;
 
                         r = dns_packet_read_uint8(p, &rr->loc.vert_pre, NULL);
                         if (r < 0)
-                                goto fail;
+                                return r;
 
-                        if (!loc_size_ok(rr->loc.vert_pre)) {
-                                r = -EBADMSG;
-                                goto fail;
-                        }
+                        if (!loc_size_ok(rr->loc.vert_pre))
+                                return -EBADMSG;
 
                         r = dns_packet_read_uint32(p, &rr->loc.latitude, NULL);
                         if (r < 0)
-                                goto fail;
+                                return r;
 
                         r = dns_packet_read_uint32(p, &rr->loc.longitude, NULL);
                         if (r < 0)
-                                goto fail;
+                                return r;
 
                         r = dns_packet_read_uint32(p, &rr->loc.altitude, NULL);
                         if (r < 0)
-                                goto fail;
+                                return r;
 
                         break;
                 } else {
@@ -1803,122 +1777,114 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl
         case DNS_TYPE_DS:
                 r = dns_packet_read_uint16(p, &rr->ds.key_tag, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint8(p, &rr->ds.algorithm, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint8(p, &rr->ds.digest_type, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_memdup(p, rdlength - 4,
                                            &rr->ds.digest, &rr->ds.digest_size,
                                            NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
-                if (rr->ds.digest_size <= 0) {
+                if (rr->ds.digest_size <= 0)
                         /* the accepted size depends on the algorithm, but for now
                            just ensure that the value is greater than zero */
-                        r = -EBADMSG;
-                        goto fail;
-                }
+                        return -EBADMSG;
 
                 break;
 
         case DNS_TYPE_SSHFP:
                 r = dns_packet_read_uint8(p, &rr->sshfp.algorithm, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint8(p, &rr->sshfp.fptype, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_memdup(p, rdlength - 2,
                                            &rr->sshfp.fingerprint, &rr->sshfp.fingerprint_size,
                                            NULL);
 
-                if (rr->sshfp.fingerprint_size <= 0) {
+                if (rr->sshfp.fingerprint_size <= 0)
                         /* the accepted size depends on the algorithm, but for now
                            just ensure that the value is greater than zero */
-                        r = -EBADMSG;
-                        goto fail;
-                }
+                        return -EBADMSG;
 
                 break;
 
         case DNS_TYPE_DNSKEY:
                 r = dns_packet_read_uint16(p, &rr->dnskey.flags, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint8(p, &rr->dnskey.protocol, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint8(p, &rr->dnskey.algorithm, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_memdup(p, rdlength - 4,
                                            &rr->dnskey.key, &rr->dnskey.key_size,
                                            NULL);
 
-                if (rr->dnskey.key_size <= 0) {
+                if (rr->dnskey.key_size <= 0)
                         /* the accepted size depends on the algorithm, but for now
                            just ensure that the value is greater than zero */
-                        r = -EBADMSG;
-                        goto fail;
-                }
+                        return -EBADMSG;
 
                 break;
 
         case DNS_TYPE_RRSIG:
                 r = dns_packet_read_uint16(p, &rr->rrsig.type_covered, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint8(p, &rr->rrsig.algorithm, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint8(p, &rr->rrsig.labels, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint32(p, &rr->rrsig.original_ttl, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint32(p, &rr->rrsig.expiration, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint32(p, &rr->rrsig.inception, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint16(p, &rr->rrsig.key_tag, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_name(p, &rr->rrsig.signer, false, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_memdup(p, offset + rdlength - p->rindex,
                                            &rr->rrsig.signature, &rr->rrsig.signature_size,
                                            NULL);
 
-                if (rr->rrsig.signature_size <= 0) {
+                if (rr->rrsig.signature_size <= 0)
                         /* the accepted size depends on the algorithm, but for now
                            just ensure that the value is greater than zero */
-                        r = -EBADMSG;
-                        goto fail;
-                }
+                        return -EBADMSG;
 
                 break;
 
@@ -1933,11 +1899,9 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl
 
                 r = dns_packet_read_name(p, &rr->nsec.next_domain_name, allow_compressed, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_type_windows(p, &rr->nsec.types, offset + rdlength - p->rindex, NULL);
-                if (r < 0)
-                        goto fail;
 
                 /* We accept empty NSEC bitmaps. The bit indicating the presence of the NSEC record itself
                  * is redundant and in e.g., RFC4956 this fact is used to define a use for NSEC records
@@ -1950,41 +1914,39 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl
 
                 r = dns_packet_read_uint8(p, &rr->nsec3.algorithm, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint8(p, &rr->nsec3.flags, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint16(p, &rr->nsec3.iterations, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 /* this may be zero */
                 r = dns_packet_read_uint8(p, &size, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_memdup(p, size, &rr->nsec3.salt, &rr->nsec3.salt_size, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint8(p, &size, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
-                if (size <= 0) {
-                        r = -EBADMSG;
-                        goto fail;
-                }
+                if (size <= 0)
+                        return -EBADMSG;
 
-                r = dns_packet_read_memdup(p, size, &rr->nsec3.next_hashed_name, &rr->nsec3.next_hashed_name_size, NULL);
+                r = dns_packet_read_memdup(p, size,
+                                           &rr->nsec3.next_hashed_name, &rr->nsec3.next_hashed_name_size,
+                                           NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_type_windows(p, &rr->nsec3.types, offset + rdlength - p->rindex, NULL);
-                if (r < 0)
-                        goto fail;
 
                 /* empty non-terminals can have NSEC3 records, so empty bitmaps are allowed */
 
@@ -1994,25 +1956,39 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl
         case DNS_TYPE_TLSA:
                 r = dns_packet_read_uint8(p, &rr->tlsa.cert_usage, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint8(p, &rr->tlsa.selector, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_uint8(p, &rr->tlsa.matching_type, NULL);
                 if (r < 0)
-                        goto fail;
+                        return r;
 
                 r = dns_packet_read_memdup(p, rdlength - 3,
                                            &rr->tlsa.data, &rr->tlsa.data_size,
                                            NULL);
-                if (rr->tlsa.data_size <= 0) {
+
+                if (rr->tlsa.data_size <= 0)
                         /* the accepted size depends on the algorithm, but for now
                            just ensure that the value is greater than zero */
-                        r = -EBADMSG;
-                        goto fail;
-                }
+                        return -EBADMSG;
+
+                break;
+
+        case DNS_TYPE_CAA:
+                r = dns_packet_read_uint8(p, &rr->caa.flags, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_string(p, &rr->caa.tag, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_memdup(p,
+                                           rdlength + offset - p->rindex,
+                                           &rr->caa.value, &rr->caa.value_size, NULL);
 
                 break;
 
@@ -2021,16 +1997,13 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl
         default:
         unparseable:
                 r = dns_packet_read_memdup(p, rdlength, &rr->generic.data, &rr->generic.data_size, NULL);
-                if (r < 0)
-                        goto fail;
+
                 break;
         }
         if (r < 0)
-                goto fail;
-        if (p->rindex != offset + rdlength) {
-                r = -EBADMSG;
-                goto fail;
-        }
+                return r;
+        if (p->rindex != offset + rdlength)
+                return -EBADMSG;
 
         *ret = rr;
         rr = NULL;
@@ -2038,12 +2011,10 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl
         if (ret_cache_flush)
                 *ret_cache_flush = cache_flush;
         if (start)
-                *start = saved_rindex;
+                *start = rewinder.saved_rindex;
+        CANCEL_REWINDER(rewinder);
 
         return 0;
-fail:
-        dns_packet_rewind(p, saved_rindex);
-        return r;
 }
 
 static bool opt_is_good(DnsResourceRecord *rr, bool *rfc6975) {
@@ -2091,23 +2062,21 @@ static bool opt_is_good(DnsResourceRecord *rr, bool *rfc6975) {
 int dns_packet_extract(DnsPacket *p) {
         _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL;
         _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
-        size_t saved_rindex;
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = {};
         unsigned n, i;
         int r;
 
         if (p->extracted)
                 return 0;
 
-        saved_rindex = p->rindex;
+        INIT_REWINDER(rewinder, p);
         dns_packet_rewind(p, DNS_PACKET_HEADER_SIZE);
 
         n = DNS_PACKET_QDCOUNT(p);
         if (n > 0) {
                 question = dns_question_new(n);
-                if (!question) {
-                        r = -ENOMEM;
-                        goto finish;
-                }
+                if (!question)
+                        return -ENOMEM;
 
                 for (i = 0; i < n; i++) {
                         _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
@@ -2115,21 +2084,17 @@ int dns_packet_extract(DnsPacket *p) {
 
                         r = dns_packet_read_key(p, &key, &cache_flush, NULL);
                         if (r < 0)
-                                goto finish;
+                                return r;
 
-                        if (cache_flush) {
-                                r = -EBADMSG;
-                                goto finish;
-                        }
+                        if (cache_flush)
+                                return -EBADMSG;
 
-                        if (!dns_type_is_valid_query(key->type)) {
-                                r = -EBADMSG;
-                                goto finish;
-                        }
+                        if (!dns_type_is_valid_query(key->type))
+                                return -EBADMSG;
 
                         r = dns_question_add(question, key);
                         if (r < 0)
-                                goto finish;
+                                return r;
                 }
         }
 
@@ -2139,10 +2104,8 @@ int dns_packet_extract(DnsPacket *p) {
                 bool bad_opt = false;
 
                 answer = dns_answer_new(n);
-                if (!answer) {
-                        r = -ENOMEM;
-                        goto finish;
-                }
+                if (!answer)
+                        return -ENOMEM;
 
                 for (i = 0; i < n; i++) {
                         _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
@@ -2150,7 +2113,7 @@ int dns_packet_extract(DnsPacket *p) {
 
                         r = dns_packet_read_rr(p, &rr, &cache_flush, NULL);
                         if (r < 0)
-                                goto finish;
+                                return r;
 
                         /* Try to reduce memory usage a bit */
                         if (previous)
@@ -2213,7 +2176,7 @@ int dns_packet_extract(DnsPacket *p) {
                                                    (i < DNS_PACKET_ANCOUNT(p) ? DNS_ANSWER_CACHEABLE : 0) |
                                                    (p->protocol == DNS_PROTOCOL_MDNS && !cache_flush ? DNS_ANSWER_SHARED_OWNER : 0));
                                 if (r < 0)
-                                        goto finish;
+                                        return r;
                         }
 
                         /* Remember this RR, so that we potentically can merge it's ->key object with the next RR. Note
@@ -2234,11 +2197,8 @@ int dns_packet_extract(DnsPacket *p) {
 
         p->extracted = true;
 
-        r = 0;
-
-finish:
-        p->rindex = saved_rindex;
-        return r;
+        /* no CANCEL, always rewind */
+        return 0;
 }
 
 int dns_packet_is_reply_for(DnsPacket *p, const DnsResourceKey *key) {
diff --git a/src/resolve/resolved-dns-rr.c b/src/resolve/resolved-dns-rr.c
index 40f8e28dfd..6397005a68 100644
--- a/src/resolve/resolved-dns-rr.c
+++ b/src/resolve/resolved-dns-rr.c
@@ -22,6 +22,7 @@
 #include "alloc-util.h"
 #include "dns-domain.h"
 #include "dns-type.h"
+#include "escape.h"
 #include "hexdecoct.h"
 #include "resolved-dns-dnssec.h"
 #include "resolved-dns-packet.h"
@@ -490,6 +491,11 @@ DnsResourceRecord* dns_resource_record_unref(DnsResourceRecord *rr) {
                         free(rr->tlsa.data);
                         break;
 
+                case DNS_TYPE_CAA:
+                        free(rr->caa.tag);
+                        free(rr->caa.value);
+                        break;
+
                 case DNS_TYPE_OPENPGPKEY:
                 default:
                         free(rr->generic.data);
@@ -697,6 +703,12 @@ int dns_resource_record_equal(const DnsResourceRecord *a, const DnsResourceRecor
                        a->tlsa.matching_type == b->tlsa.matching_type &&
                        FIELD_EQUAL(a->tlsa, b->tlsa, data);
 
+        case DNS_TYPE_CAA:
+                return a->caa.flags == b->caa.flags &&
+                       streq(a->caa.tag, b->caa.tag) &&
+                       FIELD_EQUAL(a->caa, b->caa, value);
+
+        case DNS_TYPE_OPENPGPKEY:
         default:
                 return FIELD_EQUAL(a->generic, b->generic, data);
         }
@@ -966,7 +978,7 @@ const char *dns_resource_record_to_string(DnsResourceRecord *rr) {
         case DNS_TYPE_DNSKEY: {
                 _cleanup_free_ char *alg = NULL;
                 char *ss;
-                int n, n1;
+                int n;
                 uint16_t key_tag;
 
                 key_tag = dnssec_keytag(rr, true);
@@ -975,9 +987,8 @@ const char *dns_resource_record_to_string(DnsResourceRecord *rr) {
                 if (r < 0)
                         return NULL;
 
-                r = asprintf(&s, "%s %n%u %u %s %n",
+                r = asprintf(&s, "%s %u %u %s %n",
                              k,
-                             &n1,
                              rr->dnskey.flags,
                              rr->dnskey.protocol,
                              alg,
@@ -992,14 +1003,12 @@ const char *dns_resource_record_to_string(DnsResourceRecord *rr) {
                         return NULL;
 
                 r = asprintf(&ss, "%s\n"
-                             "%*s-- Flags:%s%s%s\n"
-                             "%*s-- Key tag: %u",
+                             "        -- Flags:%s%s%s\n"
+                             "        -- Key tag: %u",
                              s,
-                             n1, "",
                              rr->dnskey.flags & DNSKEY_FLAG_SEP ? " SEP" : "",
                              rr->dnskey.flags & DNSKEY_FLAG_REVOKE ? " REVOKE" : "",
                              rr->dnskey.flags & DNSKEY_FLAG_ZONE_KEY ? " ZONE_KEY" : "",
-                             n1, "",
                              key_tag);
                 if (r < 0)
                         return NULL;
@@ -1125,13 +1134,13 @@ const char *dns_resource_record_to_string(DnsResourceRecord *rr) {
                         return NULL;
 
                 r = asprintf(&ss, "%s\n"
-                             "%*s-- Cert. usage: %s\n"
-                             "%*s-- Selector: %s\n"
-                             "%*s-- Matching type: %s",
+                             "        -- Cert. usage: %s\n"
+                             "        -- Selector: %s\n"
+                             "        -- Matching type: %s",
                              s,
-                             n - 6, "", cert_usage,
-                             n - 6, "", selector,
-                             n - 6, "", matching_type);
+                             cert_usage,
+                             selector,
+                             matching_type);
                 if (r < 0)
                         return NULL;
                 free(s);
@@ -1140,6 +1149,28 @@ const char *dns_resource_record_to_string(DnsResourceRecord *rr) {
                 break;
         }
 
+        case DNS_TYPE_CAA: {
+                _cleanup_free_ char *value;
+
+                value = octescape(rr->caa.value, rr->caa.value_size);
+                if (!value)
+                        return NULL;
+
+                r = asprintf(&s, "%s %u %s \"%s\"%s%s%s%.0u",
+                             k,
+                             rr->caa.flags,
+                             rr->caa.tag,
+                             value,
+                             rr->caa.flags ? "\n        -- Flags:" : "",
+                             rr->caa.flags & CAA_FLAG_CRITICAL ? " critical" : "",
+                             rr->caa.flags & ~CAA_FLAG_CRITICAL ? " " : "",
+                             rr->caa.flags & ~CAA_FLAG_CRITICAL);
+                if (r < 0)
+                        return NULL;
+
+                break;
+        }
+
         case DNS_TYPE_OPENPGPKEY: {
                 int n;
 
@@ -1300,7 +1331,7 @@ int dns_resource_record_is_synthetic(DnsResourceRecord *rr) {
         return !r;
 }
 
-static void dns_resource_record_hash_func(const void *i, struct siphash *state) {
+void dns_resource_record_hash_func(const void *i, struct siphash *state) {
         const DnsResourceRecord *rr = i;
 
         assert(rr);
@@ -1427,7 +1458,13 @@ static void dns_resource_record_hash_func(const void *i, struct siphash *state)
                 siphash24_compress(&rr->tlsa.cert_usage, sizeof(rr->tlsa.cert_usage), state);
                 siphash24_compress(&rr->tlsa.selector, sizeof(rr->tlsa.selector), state);
                 siphash24_compress(&rr->tlsa.matching_type, sizeof(rr->tlsa.matching_type), state);
-                siphash24_compress(&rr->tlsa.data, rr->tlsa.data_size, state);
+                siphash24_compress(rr->tlsa.data, rr->tlsa.data_size, state);
+                break;
+
+        case DNS_TYPE_CAA:
+                siphash24_compress(&rr->caa.flags, sizeof(rr->caa.flags), state);
+                string_hash_func(rr->caa.tag, state);
+                siphash24_compress(rr->caa.value, rr->caa.value_size, state);
                 break;
 
         case DNS_TYPE_OPENPGPKEY:
diff --git a/src/resolve/resolved-dns-rr.h b/src/resolve/resolved-dns-rr.h
index 2e0dfbaba3..23749790b4 100644
--- a/src/resolve/resolved-dns-rr.h
+++ b/src/resolve/resolved-dns-rr.h
@@ -249,6 +249,14 @@ struct DnsResourceRecord {
                         void *data;
                         size_t data_size;
                 } tlsa;
+
+                /* https://tools.ietf.org/html/rfc6844 */
+                struct {
+                        uint8_t flags;
+                        char *tag;
+                        void *value;
+                        size_t value_size;
+                } caa;
         };
 };
 
@@ -323,6 +331,8 @@ int dns_resource_record_is_synthetic(DnsResourceRecord *rr);
 DnsTxtItem *dns_txt_item_free_all(DnsTxtItem *i);
 bool dns_txt_item_equal(DnsTxtItem *a, DnsTxtItem *b);
 
+void dns_resource_record_hash_func(const void *i, struct siphash *state);
+
 extern const struct hash_ops dns_resource_key_hash_ops;
 extern const struct hash_ops dns_resource_record_hash_ops;
 
diff --git a/src/resolve/test-data/_443._tcp.fedoraproject.org.pkts b/src/resolve/test-data/_443._tcp.fedoraproject.org.pkts
new file mode 100644
index 0000000000..a383c6286d
--- /dev/null
+++ b/src/resolve/test-data/_443._tcp.fedoraproject.org.pkts
diff --git a/src/resolve/test-data/_openpgpkey.fedoraproject.org.pkts b/src/resolve/test-data/_openpgpkey.fedoraproject.org.pkts
new file mode 100644
index 0000000000..15de02e997
--- /dev/null
+++ b/src/resolve/test-data/_openpgpkey.fedoraproject.org.pkts
diff --git a/src/resolve/test-data/fake-caa.pkts b/src/resolve/test-data/fake-caa.pkts
new file mode 100644
index 0000000000..1c3ecc5491
--- /dev/null
+++ b/src/resolve/test-data/fake-caa.pkts
diff --git a/src/resolve/test-data/fedoraproject.org.pkts b/src/resolve/test-data/fedoraproject.org.pkts
new file mode 100644
index 0000000000..17874844d9
--- /dev/null
+++ b/src/resolve/test-data/fedoraproject.org.pkts
diff --git a/src/resolve/test-data/gandi.net.pkts b/src/resolve/test-data/gandi.net.pkts
new file mode 100644
index 0000000000..5ef51e0c8e
--- /dev/null
+++ b/src/resolve/test-data/gandi.net.pkts
diff --git a/src/resolve/test-data/google.com.pkts b/src/resolve/test-data/google.com.pkts
new file mode 100644
index 0000000000..f98c4cd855
--- /dev/null
+++ b/src/resolve/test-data/google.com.pkts
diff --git a/src/resolve/test-data/kyhwana.org.pkts b/src/resolve/test-data/kyhwana.org.pkts
new file mode 100644
index 0000000000..e28a725c9a
--- /dev/null
+++ b/src/resolve/test-data/kyhwana.org.pkts
diff --git a/src/resolve/test-data/root.pkts b/src/resolve/test-data/root.pkts
new file mode 100644
index 0000000000..54ba668c75
--- /dev/null
+++ b/src/resolve/test-data/root.pkts
diff --git a/src/resolve/test-data/sw1a1aa-sw1a2aa-sw1a2ab-sw1a2ac.find.me.uk.pkts b/src/resolve/test-data/sw1a1aa-sw1a2aa-sw1a2ab-sw1a2ac.find.me.uk.pkts
new file mode 100644
index 0000000000..a854249532
--- /dev/null
+++ b/src/resolve/test-data/sw1a1aa-sw1a2aa-sw1a2ab-sw1a2ac.find.me.uk.pkts
diff --git a/src/resolve/test-data/teamits.com.pkts b/src/resolve/test-data/teamits.com.pkts
new file mode 100644
index 0000000000..11deb39677
--- /dev/null
+++ b/src/resolve/test-data/teamits.com.pkts
diff --git a/src/resolve/test-data/zbyszek@fedoraproject.org.pkts b/src/resolve/test-data/zbyszek@fedoraproject.org.pkts
new file mode 100644
index 0000000000..f0a6f982df
--- /dev/null
+++ b/src/resolve/test-data/zbyszek@fedoraproject.org.pkts
diff --git a/src/resolve/test-dns-packet.c b/src/resolve/test-dns-packet.c
new file mode 100644
index 0000000000..1abbd3fa2e
--- /dev/null
+++ b/src/resolve/test-dns-packet.c
@@ -0,0 +1,115 @@
+/***
+  This file is part of systemd
+
+  Copyright 2016 Zbigniew Jędrzejewski-Szmek
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <net/if.h>
+#include <glob.h>
+
+#include "alloc-util.h"
+#include "fileio.h"
+#include "glob-util.h"
+#include "log.h"
+#include "macro.h"
+#include "resolved-dns-packet.h"
+#include "resolved-dns-rr.h"
+#include "string-util.h"
+#include "strv.h"
+
+#define HASH_KEY SD_ID128_MAKE(d3,1e,48,90,4b,fa,4c,fe,af,9d,d5,a1,d7,2e,8a,b1)
+
+static uint64_t hash(DnsResourceRecord *rr) {
+        struct siphash state;
+
+        siphash24_init(&state, HASH_KEY.bytes);
+        dns_resource_record_hash_func(rr, &state);
+        return siphash24_finalize(&state);
+}
+
+static void test_packet_from_file(const char* filename, bool canonical) {
+        _cleanup_free_ char *data = NULL;
+        size_t data_size, packet_size, offset;
+
+        assert_se(read_full_file(filename, &data, &data_size) >= 0);
+        assert_se(data);
+        assert_se(data_size > 8);
+
+        log_info("============== %s %s==============", filename, canonical ? "canonical " : "");
+
+        for (offset = 0; offset < data_size; offset += 8 + packet_size) {
+                _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL, *p2 = NULL;
+                _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL, *rr2 = NULL;
+                const char *s, *s2;
+                uint64_t hash1, hash2;
+
+                packet_size = le64toh( *(uint64_t*)(data + offset) );
+                assert_se(packet_size > 0);
+                assert_se(offset + 8 + packet_size <= data_size);
+
+                assert_se(dns_packet_new(&p, DNS_PROTOCOL_DNS, 0) >= 0);
+
+                assert_se(dns_packet_append_blob(p, data + offset + 8, packet_size, NULL) >= 0);
+                assert_se(dns_packet_read_rr(p, &rr, NULL, NULL) >= 0);
+
+                s = dns_resource_record_to_string(rr);
+                assert_se(s);
+                puts(s);
+
+                hash1 = hash(rr);
+
+                assert_se(dns_resource_record_to_wire_format(rr, canonical) >= 0);
+
+                assert_se(dns_packet_new(&p2, DNS_PROTOCOL_DNS, 0) >= 0);
+                assert_se(dns_packet_append_blob(p2, rr->wire_format, rr->wire_format_size, NULL) >= 0);
+                assert_se(dns_packet_read_rr(p2, &rr2, NULL, NULL) >= 0);
+
+                s2 = dns_resource_record_to_string(rr);
+                assert_se(s2);
+                assert_se(streq(s, s2));
+
+                hash2 = hash(rr);
+                assert_se(hash1 == hash2);
+        }
+}
+
+int main(int argc, char **argv) {
+        int i, N;
+        _cleanup_globfree_ glob_t g = {};
+        _cleanup_strv_free_ char **globs = NULL;
+        char **fnames;
+
+        log_parse_environment();
+
+        if (argc >= 2) {
+                N = argc - 1;
+                fnames = argv + 1;
+        } else {
+                assert_se(glob(RESOLVE_TEST_DIR "/*.pkts", GLOB_NOSORT, NULL, &g) == 0);
+                N = g.gl_pathc;
+                fnames = g.gl_pathv;
+        }
+
+        for (i = 0; i < N; i++) {
+                test_packet_from_file(fnames[i], false);
+                puts("");
+                test_packet_from_file(fnames[i], true);
+                if (i + 1 < N)
+                        puts("");
+        }
+
+        return EXIT_SUCCESS;
+}