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Commit 52a7e7cb authored by Lubos Slovak's avatar Lubos Slovak
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Documented part of nameserver private functions. 

refs #685
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src/knot/server/name-server.c
+ 371
− 21
View file @ 52a7e7cb
......@@ -10,27 +10,52 @@
#include "knot/stat/stat.h"
#include "dnslib/dnslib.h"
#include "dnslib/debug.h"
#include "other/error.h"
//static const uint8_t RCODE_MASK = 0xf0;
static const int OFFSET_FLAGS2 = 3;
static const size_t RR_FIXED_SIZE = 10;
static const size_t QUESTION_FIXED_SIZE = 4;
/*----------------------------------------------------------------------------*/
/*! \brief Maximum UDP payload with EDNS enabled. */
static const uint16_t MAX_UDP_PAYLOAD_EDNS = 4096;
/*! \brief Maximum UDP payload with EDNS disabled. */
static const uint16_t MAX_UDP_PAYLOAD = 512;
/*! \brief Supported EDNS version. */
static const uint8_t EDNS_VERSION = 0;
static const uint8_t OPT_SIZE = 11;
/*! \brief Determines whether EDNS is enabled. */
static const int EDNS_ENABLED = 1;
/*! \brief TTL of a CNAME synthetized from a DNAME. */
static const uint32_t SYNTH_CNAME_TTL = 0;
/*! \brief Determines whether DNSSEC is enabled. */
static const int DNSSEC_ENABLED = 1;
/*! \brief Determines whether NSID is enabled. */
static const int NSID_ENABLED = 1;
/*! \brief Length of NSID option data. */
static const uint16_t NSID_LENGTH = 6;
/*! \brief NSID option data. */
static const uint8_t NSID_DATA[6] = {0x46, 0x6f, 0x6f, 0x42, 0x61, 0x72};
/*! \brief Internal error code to propagate need for SERVFAIL response. */
static const int NS_ERR_SERVFAIL = -999;
/*----------------------------------------------------------------------------*/
/* Private functions */
/*----------------------------------------------------------------------------*/
/*!
* \brief Prepares wire format of an error response using generic error template
* stored in the nameserver structure.
*
* The error response will not contain the Question section from the query, just
* a header with ID copied from the query and the given RCODE.
*
* \param nameserver Nameserver structure containing the error template.
* \param query_wire Wire format of the query.
* \param rcode RCODE to set in the response.
* \param response_wire Place for wire format of the response.
* \param rsize Size of the error response will be stored here.
*/
static inline void ns_error_response(ns_nameserver *nameserver,
const uint8_t *query_wire,
uint8_t rcode,
......@@ -47,7 +72,19 @@ static inline void ns_error_response(ns_nameserver *nameserver,
}
/*----------------------------------------------------------------------------*/
/*!
* \brief Finds zone where to search for the QNAME.
*
* \note As QTYPE DS requires special handling, this function finds a zone for
* a direct predecessor of QNAME in such case.
*
* \param zdb Zone database where to search for the proper zone.
* \param qname QNAME.
* \param qtype QTYPE.
*
* \return Zone to which QNAME belongs (according to QTYPE), or NULL if no such
* zone was found.
*/
static const dnslib_zone_t *ns_get_zone_for_qname(dnslib_zonedb_t *zdb,
const dnslib_dname_t *qname,
uint16_t qtype)
......@@ -76,7 +113,18 @@ static const dnslib_zone_t *ns_get_zone_for_qname(dnslib_zonedb_t *zdb,
}
/*----------------------------------------------------------------------------*/
/*!
* \brief Synthetizes RRSet from a wildcard RRSet using the given QNAME.
*
* The synthetized RRSet is identical to the wildcard RRSets, except that the
* owner name is replaced by \a qname.
*
* \param wildcard_rrset Wildcard RRSet to synthetize from.
* \param qname Domain name to be used as the owner of the synthetized RRset.
*
* \return The synthetized RRSet (this is a newly created RRSet, remember to
* free it).
*/
dnslib_rrset_t *ns_synth_from_wildcard(const dnslib_rrset_t *wildcard_rrset,
const dnslib_dname_t *qname)
{
......@@ -122,7 +170,16 @@ dnslib_rrset_t *ns_synth_from_wildcard(const dnslib_rrset_t *wildcard_rrset,
}
/*----------------------------------------------------------------------------*/
/*!
* \brief Checks if the given RRSet is a wildcard RRSet and replaces it with
* a synthetized RRSet if required.
*
* \param name Domain name to be used as the owner of the possibly synthetized
* RRSet
* \param resp Response to which the synthetized RRSet should be stored (as a
* temporary RRSet).
* \param rrset RRSet to check (and possibly replace).
*/
static void ns_check_wildcard(const dnslib_dname_t *name,
dnslib_response_t *resp,
const dnslib_rrset_t **rrset)
......@@ -138,7 +195,26 @@ static void ns_check_wildcard(const dnslib_dname_t *name,
}
/*----------------------------------------------------------------------------*/
/*!
* \brief Adds signatures (RRSIGs) for the given RRSet to the response.
*
* This function first checks if DNSSEC is enabled and if it was requested in
* the response (DO bit set). If not, it does nothing and returns 0. If yes,
* it retrieves RRSIGs stored in the RRSet, deals with possible wildcard owner
* and adds the RRSIGs to response using the given function (that determines
* to which section of the response they will be added).
*
* \param rrset RRSet to get the RRSIGs from.
* \param resp Response where to add the RRSIGs.
* \param name Actual name to be used as owner in case of wildcard RRSet.
* \param add_rrset_to_resp Function for adding the RRSIG RRset to the response.
* \param tc Set to 1 if omitting the RRSIG RRSet should result in setting the
* TC bit in the response.
*
* \return KNOT_EOK
* \return DNSLIB_ENOMEM
* \return DNSLIB_ESPACE
*/
static int ns_add_rrsigs(const dnslib_rrset_t *rrset, dnslib_response_t *resp,
const dnslib_dname_t *name,
int (*add_rrset_to_resp)(dnslib_response_t *,
......@@ -160,11 +236,22 @@ static int ns_add_rrsigs(const dnslib_rrset_t *rrset, dnslib_response_t *resp,
return add_rrset_to_resp(resp, rrsigs, tc, 0);
}
return 0;
return KNOT_EOK;
}
/*----------------------------------------------------------------------------*/
/*!
* \brief Resolves CNAME chain starting in \a node, stores all the CNAMEs in the
* response and updates \a node and \a qname to the last node in the
* chain.
*
* \param node Node (possibly) containing a CNAME RR.
* \param qname Searched name. Will be updated to the canonical name.
* \param resp Response where to add the CNAME RRs.
* \param add_rrset_to_resp Function for adding the CNAME RRs to the response.
* \param tc Set to 1 if omitting the RRSIG RRSet should result in setting the
* TC bit in the response.
*/
static void ns_follow_cname(const dnslib_node_t **node,
const dnslib_dname_t **qname,
dnslib_response_t *resp,
......@@ -217,6 +304,18 @@ DEBUG_NS(
/*----------------------------------------------------------------------------*/
/*!
* \brief Retrieves RRSet(s) of given type from the given node and adds them to
* the response's Answer section.
*
* \param node Node where to take the RRSet from.
* \param name Actual searched name (used in case of wildcard RRSet(s)).
* \param type Type of the RRSet(s). If set to DNSLIB_RRTYPE_ANY, all RRSets
* from the node will be added to the answer.
* \param resp Response where to add the RRSets.
*
* \return Number of RRSets added.
*/
static int ns_put_answer(const dnslib_node_t *node, const dnslib_dname_t *name,
uint16_t type, dnslib_response_t *resp)
{
......@@ -316,6 +415,23 @@ DEBUG_NS(
/*----------------------------------------------------------------------------*/
/*!
* \brief Adds RRSets to Additional section of the response.
*
* This function uses dnslib_rdata_get_name() to get the domain name from the
* RDATA of the RRSet according to its type. It also does not search for the
* retrieved domain name, but just uses its node field. Thus to work correctly,
* the zone where the RRSet is from should be adjusted using
* dnslib_zone_adjust_dnames().
*
* A and AAAA RRSets (and possible CNAMEs) for the found domain names are added.
*
* \warning Use this function only with types containing some domain name,
* otherwise it will crash (or behave strangely).
*
* \param resp Response where to add the Additional data.
* \param rrset RRSet to get the Additional data for.
*/
static void ns_put_additional_for_rrset(dnslib_response_t *resp,
const dnslib_rrset_t *rrset)
{
......@@ -329,7 +445,7 @@ static void ns_put_additional_for_rrset(dnslib_response_t *resp,
debug_ns("Getting name from RDATA, type %s..\n",
dnslib_rrtype_to_string(dnslib_rrset_type(rrset)));
dname = dnslib_rdata_get_name(rdata,
dnslib_rrset_type(rrset));
dnslib_rrset_type(rrset));
assert(dname != NULL);
node = dnslib_dname_node(dname);
......@@ -393,6 +509,16 @@ DEBUG_NS(
/*----------------------------------------------------------------------------*/
/*!
* \brief Checks whether the given type requires additional processing.
*
* Only MX, NS and SRV types require additional processing.
*
* \param qtype Type to check.
*
* \retval <> 0 if additional processing is needed for \a qtype.
* \retval 0 otherwise.
*/
static int ns_additional_needed(uint16_t qtype)
{
return (qtype == DNSLIB_RRTYPE_MX ||
......@@ -402,6 +528,15 @@ static int ns_additional_needed(uint16_t qtype)
/*----------------------------------------------------------------------------*/
/*!
* \brief Adds whatever Additional RRSets are required for the response.
*
* For each RRSet in Answer and Authority sections this function checks if
* additional processing is needed and if yes, it puts any Additional RRSets
* available to the Additional section of the response.
*
* \param resp Response to process.
*/
static void ns_put_additional(dnslib_response_t *resp)
{
debug_ns("ADDITIONAL SECTION PROCESSING\n");
......@@ -426,6 +561,12 @@ static void ns_put_additional(dnslib_response_t *resp)
/*----------------------------------------------------------------------------*/
/*!
* \brief Puts authority NS RRSet to the Auhority section of the response.
*
* \param zone Zone to take the authority NS RRSet from.
* \param resp Response where to add the RRSet.
*/
static void ns_put_authority_ns(const dnslib_zone_t *zone,
dnslib_response_t *resp)
{
......@@ -440,6 +581,12 @@ static void ns_put_authority_ns(const dnslib_zone_t *zone,
/*----------------------------------------------------------------------------*/
/*!
* \brief Puts SOA RRSet to the Auhority section of the response.
*
* \param zone Zone to take the SOA RRSet from.
* \param resp Response where to add the RRSet.
*/
static void ns_put_authority_soa(const dnslib_zone_t *zone,
dnslib_response_t *resp)
{
......@@ -454,20 +601,31 @@ static void ns_put_authority_soa(const dnslib_zone_t *zone,
/*----------------------------------------------------------------------------*/
/*!
* \brief Creates a 'next closer name' to the given domain name.
*
* For definition of 'next closer name', see RFC5155, Page 6.
*
* \param closest_encloser Closest encloser of \a name.
* \param name Domain name to create the 'next closer' name to.
*
* \return 'Next closer name' to the given domain name or NULL if an error
* occured.
*/
static dnslib_dname_t *ns_next_closer(const dnslib_dname_t *closest_encloser,
const dnslib_dname_t *qname)
const dnslib_dname_t *name)
{
int ce_labels = dnslib_dname_label_count(closest_encloser);
int qname_labels = dnslib_dname_label_count(qname);
int qname_labels = dnslib_dname_label_count(name);
assert(ce_labels < qname_labels);
// the common labels should match
assert(dnslib_dname_matched_labels(closest_encloser, qname)
assert(dnslib_dname_matched_labels(closest_encloser, name)
== ce_labels);
// chop some labels from the qname
dnslib_dname_t *next_closer = dnslib_dname_copy(qname);
dnslib_dname_t *next_closer = dnslib_dname_copy(name);
if (next_closer == NULL) {
return NULL;
}
......@@ -481,6 +639,13 @@ static dnslib_dname_t *ns_next_closer(const dnslib_dname_t *closest_encloser,
/*----------------------------------------------------------------------------*/
/*!
* \brief Adds NSEC3 RRSet (together with corresponding RRSIGs) from the given
* node into the response.
*
* \param node Node to get the NSEC3 RRSet from.
* \param resp Response where to add the RRSets.
*/
static void ns_put_nsec3_from_node(const dnslib_node_t *node,
dnslib_response_t *resp)
{
......@@ -499,12 +664,24 @@ static void ns_put_nsec3_from_node(const dnslib_node_t *node,
/*----------------------------------------------------------------------------*/
/*!
* \brief Finds and adds NSEC3 covering the given domain name (and their
* associated RRSIGs) to the response.
*
* \param zone Zone where to take the NSEC3s from.
* \param name Domain name to cover.
* \param resp Response where to add the RRSets.
*
* \retval KNOT_OK
* \retval NS_ERR_SERVFAIL if a runtime collision occured. The server should
* respond with SERVFAIL in such case.
*/
static int ns_put_covering_nsec3(const dnslib_zone_t *zone,
const dnslib_dname_t *nsec3_name,
dnslib_response_t *resp)
const dnslib_dname_t *name,
dnslib_response_t *resp)
{
const dnslib_node_t *prev, *node;
int match = dnslib_zone_find_nsec3_for_name(zone, nsec3_name,
int match = dnslib_zone_find_nsec3_for_name(zone, name,
&node, &prev);
if (match == DNSLIB_ZONE_NAME_FOUND){
......@@ -520,11 +697,21 @@ DEBUG_NS(
ns_put_nsec3_from_node(prev, resp);
return 0;
return KNOT_OK;
}
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param zone
* \param closest_encloser
* \param qname
* \param resp
*
* \return int
*/
static int ns_put_nsec3_closest_encloser_proof(const dnslib_zone_t *zone,
const dnslib_node_t **closest_encloser,
const dnslib_dname_t *qname,
......@@ -609,6 +796,12 @@ DEBUG_NS(
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param name
* \return dnslib_dname_t *
*/
static dnslib_dname_t *ns_wildcard_child_name(const dnslib_dname_t *name)
{
assert(name != NULL);
......@@ -633,6 +826,14 @@ DEBUG_NS(
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param zone
* \param node
* \param resp
* \return int
*/
static int ns_put_nsec3_no_wildcard_child(const dnslib_zone_t *zone,
const dnslib_node_t *node,
dnslib_response_t *resp)
......@@ -654,6 +855,12 @@ static int ns_put_nsec3_no_wildcard_child(const dnslib_zone_t *zone,
}
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param node
* \param resp
*/
static void ns_put_nsec_nsec3_nodata(const dnslib_node_t *node,
dnslib_response_t *resp)
{
......@@ -676,6 +883,16 @@ static void ns_put_nsec_nsec3_nodata(const dnslib_node_t *node,
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param qname
* \param zone
* \param previous
* \param closest_encloser
* \param resp
* \return int
*/
static int ns_put_nsec_nxdomain(const dnslib_dname_t *qname,
const dnslib_zone_t *zone,
const dnslib_node_t *previous,
......@@ -745,6 +962,15 @@ static int ns_put_nsec_nxdomain(const dnslib_dname_t *qname,
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param zone
* \param closest_encloser
* \param qname
* \param resp
* \return int
*/
static int ns_put_nsec3_nxdomain(const dnslib_zone_t *zone,
const dnslib_node_t *closest_encloser,
const dnslib_dname_t *qname,
......@@ -764,6 +990,16 @@ static int ns_put_nsec3_nxdomain(const dnslib_zone_t *zone,
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param zone
* \param previous
* \param closest_encloser
* \param qname
* \param resp
* \return int
*/
static int ns_put_nsec_nsec3_nxdomain(const dnslib_zone_t *zone,
const dnslib_node_t *previous,
const dnslib_node_t *closest_encloser,
......@@ -785,6 +1021,15 @@ static int ns_put_nsec_nsec3_nxdomain(const dnslib_zone_t *zone,
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param zone
* \param closest_encloser
* \param qname
* \param resp
* \return int
*/
static int ns_put_nsec3_wildcard(const dnslib_zone_t *zone,
const dnslib_node_t *closest_encloser,
const dnslib_dname_t *qname,
......@@ -820,6 +1065,15 @@ DEBUG_NS(
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param zone
* \param qname
* \param node
* \param previous
* \param resp
*/
static void ns_put_nsec_wildcard(const dnslib_zone_t *zone,
const dnslib_dname_t *qname,
const dnslib_node_t *node,
......@@ -847,6 +1101,17 @@ static void ns_put_nsec_wildcard(const dnslib_zone_t *zone,
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param node
* \param closest_encloser
* \param previous
* \param zone
* \param qname
* \param resp
* \return int
*/
static int ns_put_nsec_nsec3_wildcard_nodata(const dnslib_node_t *node,
const dnslib_node_t *closest_encloser,
const dnslib_node_t *previous,
......@@ -876,6 +1141,17 @@ static int ns_put_nsec_nsec3_wildcard_nodata(const dnslib_node_t *node,
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param node
* \param closest_encloser
* \param previous
* \param zone
* \param qname
* \param resp
* \return int
*/
static int ns_put_nsec_nsec3_wildcard_answer(const dnslib_node_t *node,
const dnslib_node_t *closest_encloser,
const dnslib_node_t *previous,
......@@ -898,6 +1174,15 @@ static int ns_put_nsec_nsec3_wildcard_answer(const dnslib_node_t *node,
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param node
* \param zone
* \param qname
* \param resp
* \return int
*/
static inline int ns_referral(const dnslib_node_t *node,
const dnslib_zone_t *zone,
const dnslib_dname_t *qname,
......@@ -959,6 +1244,18 @@ static inline int ns_referral(const dnslib_node_t *node,
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param node
* \param closest_encloser
* \param previous
* \param zone
* \param qname
* \param qtype
* \param resp
* \return int
*/
static int ns_answer_from_node(const dnslib_node_t *node,
const dnslib_node_t *closest_encloser,
const dnslib_node_t *previous,
......@@ -1001,6 +1298,13 @@ static int ns_answer_from_node(const dnslib_node_t *node,
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param dname_rrset
* \param qname
* \return dnslib_rrset_t *
*/
static dnslib_rrset_t *ns_cname_from_dname(const dnslib_rrset_t *dname_rrset,
const dnslib_dname_t *qname)
{
......@@ -1043,6 +1347,13 @@ DEBUG_NS(
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param dname_rrset
* \param qname
* \return int
*/
static int ns_dname_is_too_long(const dnslib_rrset_t *dname_rrset,
const dnslib_dname_t *qname)
{
......@@ -1060,6 +1371,13 @@ static int ns_dname_is_too_long(const dnslib_rrset_t *dname_rrset,
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param dname_rrset
* \param qname
* \param resp
*/
static void ns_process_dname(const dnslib_rrset_t *dname_rrset,
const dnslib_dname_t *qname,
dnslib_response_t *resp)
......@@ -1096,6 +1414,12 @@ DEBUG_NS(
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param apex
* \param resp
*/
static void ns_add_dnskey(const dnslib_node_t *apex, dnslib_response_t *resp)
{
......@@ -1110,6 +1434,15 @@ static void ns_add_dnskey(const dnslib_node_t *apex, dnslib_response_t *resp)
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param zone
* \param qname
* \param qtype
* \param resp
* \return int
*/
static int ns_answer_from_zone(const dnslib_zone_t *zone,
const dnslib_dname_t *qname, uint16_t qtype,
dnslib_response_t *resp)
......@@ -1275,6 +1608,13 @@ finalize:
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param db
* \param resp
* \return int
*/
static int ns_answer(dnslib_zonedb_t *db, dnslib_response_t *resp)
{
dnslib_dname_t *qname = resp->question.qname;
......@@ -1307,6 +1647,14 @@ DEBUG_NS(
/*----------------------------------------------------------------------------*/
/*!
* \brief
*
* \param resp
* \param wire
* \param wire_size
* \return int
*/
static int ns_response_to_wire(dnslib_response_t *resp, uint8_t *wire,
size_t *wire_size)
{
......@@ -1494,6 +1842,8 @@ void ns_destroy(ns_nameserver **nameserver)
*nameserver = NULL;
}
/*----------------------------------------------------------------------------*/
int ns_conf_hook(const struct conf_t *conf, void *data)
{
ns_nameserver *ns = (ns_nameserver *)data;
......
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