diff options
Diffstat (limited to 'src/resolve/dns-type.c')
-rw-r--r-- | src/resolve/dns-type.c | 270 |
1 files changed, 264 insertions, 6 deletions
diff --git a/src/resolve/dns-type.c b/src/resolve/dns-type.c index a626ecf01a..49210b2ca9 100644 --- a/src/resolve/dns-type.c +++ b/src/resolve/dns-type.c @@ -19,7 +19,11 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ +#include <sys/socket.h> + #include "dns-type.h" +#include "parse-util.h" +#include "string-util.h" typedef const struct { uint16_t type; @@ -38,13 +42,267 @@ int dns_type_from_string(const char *s) { assert(s); sc = lookup_dns_type(s, strlen(s)); - if (!sc) - return _DNS_TYPE_INVALID; + if (sc) + return sc->id; + + s = startswith_no_case(s, "TYPE"); + if (s) { + unsigned x; + + if (safe_atou(s, &x) >= 0 && + x <= UINT16_MAX) + return (int) x; + } + + return _DNS_TYPE_INVALID; +} + +bool dns_type_is_pseudo(uint16_t type) { + + /* Checks whether the specified type is a "pseudo-type". What + * a "pseudo-type" precisely is, is defined only very weakly, + * but apparently entails all RR types that are not actually + * stored as RRs on the server and should hence also not be + * cached. We use this list primarily to validate NSEC type + * bitfields, and to verify what to cache. */ + + return IN_SET(type, + 0, /* A Pseudo RR type, according to RFC 2931 */ + DNS_TYPE_ANY, + DNS_TYPE_AXFR, + DNS_TYPE_IXFR, + DNS_TYPE_OPT, + DNS_TYPE_TSIG, + DNS_TYPE_TKEY + ); +} + +bool dns_class_is_pseudo(uint16_t class) { + return class == DNS_TYPE_ANY; +} + +bool dns_type_is_valid_query(uint16_t type) { + + /* The types valid as questions in packets */ + + return !IN_SET(type, + 0, + DNS_TYPE_OPT, + DNS_TYPE_TSIG, + DNS_TYPE_TKEY, + + /* RRSIG are technically valid as questions, but we refuse doing explicit queries for them, as + * they aren't really payload, but signatures for payload, and cannot be validated on their + * own. After all they are the signatures, and have no signatures of their own validating + * them. */ + DNS_TYPE_RRSIG); +} + +bool dns_type_is_valid_rr(uint16_t type) { + + /* The types valid as RR in packets (but not necessarily + * stored on servers). */ + + return !IN_SET(type, + DNS_TYPE_ANY, + DNS_TYPE_AXFR, + DNS_TYPE_IXFR); +} + +bool dns_class_is_valid_rr(uint16_t class) { + return class != DNS_CLASS_ANY; +} + +bool dns_type_may_redirect(uint16_t type) { + /* The following record types should never be redirected using + * CNAME/DNAME RRs. See + * <https://tools.ietf.org/html/rfc4035#section-2.5>. */ + + if (dns_type_is_pseudo(type)) + return false; + + return !IN_SET(type, + DNS_TYPE_CNAME, + DNS_TYPE_DNAME, + DNS_TYPE_NSEC3, + DNS_TYPE_NSEC, + DNS_TYPE_RRSIG, + DNS_TYPE_NXT, + DNS_TYPE_SIG, + DNS_TYPE_KEY); +} + +bool dns_type_may_wildcard(uint16_t type) { + + /* The following records may not be expanded from wildcard RRsets */ + + if (dns_type_is_pseudo(type)) + return false; + + return !IN_SET(type, + DNS_TYPE_NSEC3, + DNS_TYPE_SOA, + + /* Prohibited by https://tools.ietf.org/html/rfc4592#section-4.4 */ + DNS_TYPE_DNAME); +} + +bool dns_type_apex_only(uint16_t type) { + + /* Returns true for all RR types that may only appear signed in a zone apex */ + + return IN_SET(type, + DNS_TYPE_SOA, + DNS_TYPE_NS, /* this one can appear elsewhere, too, but not signed */ + DNS_TYPE_DNSKEY, + DNS_TYPE_NSEC3PARAM); +} + +bool dns_type_is_dnssec(uint16_t type) { + return IN_SET(type, + DNS_TYPE_DS, + DNS_TYPE_DNSKEY, + DNS_TYPE_RRSIG, + DNS_TYPE_NSEC, + DNS_TYPE_NSEC3, + DNS_TYPE_NSEC3PARAM); +} + +bool dns_type_is_obsolete(uint16_t type) { + return IN_SET(type, + /* Obsoleted by RFC 973 */ + DNS_TYPE_MD, + DNS_TYPE_MF, + DNS_TYPE_MAILA, + + /* Kinda obsoleted by RFC 2505 */ + DNS_TYPE_MB, + DNS_TYPE_MG, + DNS_TYPE_MR, + DNS_TYPE_MINFO, + DNS_TYPE_MAILB, + + /* RFC1127 kinda obsoleted this by recommending against its use */ + DNS_TYPE_WKS, + + /* Declared historical by RFC 6563 */ + DNS_TYPE_A6, - return sc->id; + /* Obsoleted by DNSSEC-bis */ + DNS_TYPE_NXT, + + /* RFC 1035 removed support for concepts that needed this from RFC 883 */ + DNS_TYPE_NULL); +} + +int dns_type_to_af(uint16_t t) { + switch (t) { + + case DNS_TYPE_A: + return AF_INET; + + case DNS_TYPE_AAAA: + return AF_INET6; + + case DNS_TYPE_ANY: + return AF_UNSPEC; + + default: + return -EINVAL; + } +} + +const char *dns_class_to_string(uint16_t class) { + + switch (class) { + + case DNS_CLASS_IN: + return "IN"; + + case DNS_CLASS_ANY: + return "ANY"; + } + + return NULL; +} + +int dns_class_from_string(const char *s) { + + if (!s) + return _DNS_CLASS_INVALID; + + if (strcaseeq(s, "IN")) + return DNS_CLASS_IN; + else if (strcaseeq(s, "ANY")) + return DNS_CLASS_ANY; + + return _DNS_CLASS_INVALID; +} + +const char* tlsa_cert_usage_to_string(uint8_t cert_usage) { + + switch (cert_usage) { + + case 0: + return "CA constraint"; + + case 1: + return "Service certificate constraint"; + + case 2: + return "Trust anchor assertion"; + + case 3: + return "Domain-issued certificate"; + + case 4 ... 254: + return "Unassigned"; + + case 255: + return "Private use"; + } + + return NULL; /* clang cannot count that we covered everything */ } -/* XXX: find an authoritative list of all pseudo types? */ -bool dns_type_is_pseudo(uint16_t n) { - return IN_SET(n, DNS_TYPE_ANY, DNS_TYPE_AXFR, DNS_TYPE_IXFR, DNS_TYPE_OPT); +const char* tlsa_selector_to_string(uint8_t selector) { + switch (selector) { + + case 0: + return "Full Certificate"; + + case 1: + return "SubjectPublicKeyInfo"; + + case 2 ... 254: + return "Unassigned"; + + case 255: + return "Private use"; + } + + return NULL; +} + +const char* tlsa_matching_type_to_string(uint8_t selector) { + + switch (selector) { + + case 0: + return "No hash used"; + + case 1: + return "SHA-256"; + + case 2: + return "SHA-512"; + + case 3 ... 254: + return "Unassigned"; + + case 255: + return "Private use"; + } + + return NULL; } |