Adding upstream version 5.6.0.upstream/5.6.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 420 insertions, 0 deletions

diff --git a/lib/resolve.h b/lib/resolve.h
new file mode 100644
index 0000000..97ba07b
--- /dev/null
+++ b/lib/resolve.h
@@ -0,0 +1,420 @@
+/*  Copyright (C) CZ.NIC, z.s.p.o. <knot-resolver@labs.nic.cz>
+ *  SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#pragma once
+
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <libknot/packet/pkt.h>
+
+#include "lib/cookies/control.h"
+#include "lib/cookies/lru_cache.h"
+#include "lib/layer.h"
+#include "lib/generic/array.h"
+#include "lib/selection.h"
+#include "lib/rplan.h"
+#include "lib/module.h"
+#include "lib/cache/api.h"
+
+/**
+ * @file resolve.h
+ * @brief The API provides an API providing a "consumer-producer"-like interface to enable
+ * user to plug it into existing event loop or I/O code.
+ *
+ * # Example usage of the iterative API:
+ *
+ * @code{.c}
+ *
+ * // Create request and its memory pool
+ * struct kr_request req = {
+ * 	.pool = {
+ * 		.ctx = mp_new (4096),
+ * 		.alloc = (mm_alloc_t) mp_alloc
+ * 	}
+ * };
+ *
+ * // Setup and provide input query
+ * int state = kr_resolve_begin(&req, ctx);
+ * state = kr_resolve_consume(&req, query);
+ *
+ * // Generate answer
+ * while (state == KR_STATE_PRODUCE) {
+ *
+ *     // Additional query generate, do the I/O and pass back answer
+ *     state = kr_resolve_produce(&req, &addr, &type, query);
+ *     while (state == KR_STATE_CONSUME) {
+ *         int ret = sendrecv(addr, proto, query, resp);
+ *
+ *         // If I/O fails, make "resp" empty
+ *         state = kr_resolve_consume(&request, addr, resp);
+ *         knot_pkt_clear(resp);
+ *     }
+ *     knot_pkt_clear(query);
+ * }
+ *
+ * // "state" is either DONE or FAIL
+ * kr_resolve_finish(&request, state);
+ *
+ * @endcode
+ */
+
+
+struct kr_request;
+/** Allocate buffer for answer's wire (*maxlen may get lowered).
+ *
+ * Motivation: XDP wire allocation is an overlap of library and daemon:
+ *  - it needs to be called from the library
+ *  - it needs to rely on some daemon's internals
+ *  - the library (currently) isn't allowed to directly use symbols from daemon
+ *    (contrary to modules), e.g. some of our lib-using tests run without daemon
+ *
+ * Note: after we obtain the wire, we're obliged to send it out.
+ * (So far there's no use case to allow cancelling at that point.)
+ */
+typedef uint8_t * (*alloc_wire_f)(struct kr_request *req, uint16_t *maxlen);
+
+/**
+ * RRset rank - for cache and ranked_rr_*.
+ *
+ * The rank meaning consists of one independent flag - KR_RANK_AUTH,
+ * and the rest have meaning of values where only one can hold at any time.
+ * You can use one of the enums as a safe initial value, optionally | KR_RANK_AUTH;
+ * otherwise it's best to manipulate ranks via the kr_rank_* functions.
+ *
+ * @note The representation is complicated by restrictions on integer comparison:
+ * - AUTH must be > than !AUTH
+ * - AUTH INSECURE must be > than AUTH (because it attempted validation)
+ * - !AUTH SECURE must be > than AUTH (because it's valid)
+ *
+ * See also:
+ *   https://tools.ietf.org/html/rfc2181#section-5.4.1
+ *   https://tools.ietf.org/html/rfc4035#section-4.3
+ */
+enum kr_rank {
+	/* Initial-like states.  No validation has been attempted (yet). */
+	KR_RANK_INITIAL = 0, /**< Did not attempt to validate. It's assumed
+					compulsory to validate (or prove insecure). */
+	KR_RANK_OMIT,        /**< Do not attempt to validate.
+					(And don't consider it a validation failure.) */
+	KR_RANK_TRY,         /**< Attempt to validate, but failures are non-fatal. */
+
+	/* Failure states.  These have higher value because they have more information. */
+	KR_RANK_INDET = 4,   /**< Unable to determine whether it should be secure. */
+	KR_RANK_BOGUS,       /**< Ought to be secure but isn't. */
+	KR_RANK_MISMATCH,
+	KR_RANK_MISSING,     /**< No RRSIG found for that owner+type combination. */
+
+	/** Proven to be insecure, i.e. we have a chain of trust from TAs
+	 * that cryptographically denies the possibility of existence
+	 * of a positive chain of trust from the TAs to the record.
+	 * Or it may be covered by a closer negative TA. */
+	KR_RANK_INSECURE = 8,
+
+	/** Authoritative data flag; the chain of authority was "verified".
+	 *  Even if not set, only in-bailiwick stuff is acceptable,
+	 *  i.e. almost authoritative (example: mandatory glue and its NS RR). */
+	KR_RANK_AUTH = 16,
+
+	KR_RANK_SECURE = 32,  /**< Verified whole chain of trust from the closest TA. */
+	/* @note Rank must not exceed 6 bits */
+};
+
+/** Check that a rank value is valid.  Meant for assertions. */
+bool kr_rank_check(uint8_t rank) KR_PURE;
+
+/** Test the presence of any flag/state in a rank, i.e. including KR_RANK_AUTH. */
+bool kr_rank_test(uint8_t rank, uint8_t kr_flag) KR_PURE KR_EXPORT;
+
+/** Set the rank state. The _AUTH flag is kept as it was. */
+static inline void kr_rank_set(uint8_t *rank, uint8_t kr_flag)
+{
+	if (kr_fails_assert(rank && kr_rank_check(*rank)))
+		return;
+	if (kr_fails_assert(kr_rank_check(kr_flag) && !(kr_flag & KR_RANK_AUTH)))
+		return;
+	*rank = kr_flag | (*rank & KR_RANK_AUTH);
+}
+
+
+/** @cond internal Array of modules. */
+typedef array_t(struct kr_module *) module_array_t;
+/* @endcond */
+
+/**
+ * Name resolution context.
+ *
+ * Resolution context provides basic services like cache, configuration and options.
+ *
+ * @note This structure is persistent between name resolutions and may
+ *       be shared between threads.
+ */
+struct kr_context
+{
+	/** Default kr_request flags.  For startup defaults see init_resolver() */
+	struct kr_qflags options;
+
+	/** Default EDNS towards *both* clients and upstream.
+	 * LATER: consider splitting the two, e.g. allow separately
+	 * configured limits for UDP packet size (say, LAN is under control). */
+	knot_rrset_t *downstream_opt_rr;
+	knot_rrset_t *upstream_opt_rr;
+
+	trie_t *trust_anchors;
+	trie_t *negative_anchors;
+	struct kr_zonecut root_hints;
+	struct kr_cache cache;
+	unsigned cache_rtt_tout_retry_interval;
+	module_array_t *modules;
+	/* The cookie context structure should not be held within the cookies
+	 * module because of better access. */
+	struct kr_cookie_ctx cookie_ctx;
+	kr_cookie_lru_t *cache_cookie;
+	int32_t tls_padding; /**< See net.tls_padding in ../daemon/README.rst -- -1 is "true" (default policy), 0 is "false" (no padding) */
+	knot_mm_t *pool;
+};
+
+/* Kept outside, because kres-gen.lua can't handle this depth
+ * (and lines here were too long anyway). */
+struct kr_request_qsource_flags {
+	bool tcp:1; /**< true if the request is not on UDP; only meaningful if (dst_addr). */
+	bool tls:1; /**< true if the request is encrypted; only meaningful if (dst_addr). */
+	bool http:1; /**< true if the request is on HTTP; only meaningful if (dst_addr). */
+	bool xdp:1; /**< true if the request is on AF_XDP; only meaningful if (dst_addr). */
+};
+
+/* Extended DNS Errors, RFC 8914 */
+struct kr_extended_error {
+	int32_t info_code;  /**< May contain -1 (KNOT_EDNS_EDE_NONE); filter before converting to uint16_t. */
+	const char *extra_text; /**< Can be NULL.  Allocated on the kr_request::pool or static. */
+};
+
+
+typedef bool (*addr_info_f)(struct sockaddr*);
+typedef void (*async_resolution_f)(knot_dname_t*, enum knot_rr_type);
+typedef array_t(union kr_sockaddr) kr_sockaddr_array_t;
+
+/**
+ * Name resolution request.
+ *
+ * Keeps information about current query processing between calls to
+ * processing APIs, i.e. current resolved query, resolution plan, ...
+ * Use this instead of the simple interface if you want to implement
+ * multiplexing or custom I/O.
+ *
+ * @note All data for this request must be allocated from the given pool.
+ */
+struct kr_request {
+	struct kr_context *ctx;
+	knot_pkt_t *answer; /**< See kr_request_ensure_answer() */
+	struct kr_query *current_query;    /**< Current evaluated query. */
+	struct {
+		/** Address that originated the request. May be that of a client
+		 * behind a proxy, if PROXYv2 is used. Otherwise, it will be
+		 * the same as `comm_addr`. `NULL` for internal origin. */
+		const struct sockaddr *addr;
+		/** Address that communicated the request. This may be the address
+		 * of a proxy. It is the same as `addr` if no proxy is used.
+		 * `NULL` for internal origin. */
+		const struct sockaddr *comm_addr;
+		/** Address that accepted the request. `NULL` for internal origin.
+		 * Beware: in case of UDP on wildcard address it will be wildcard;
+		 * closely related: issue #173. */
+		const struct sockaddr *dst_addr;
+		const knot_pkt_t *packet;
+		/** Request flags from the point of view of the original client.
+		 * This client may be behind a proxy. */
+		struct kr_request_qsource_flags flags;
+		/** Request flags from the point of view of the client actually
+		 * communicating with the resolver. When PROXYv2 protocol is used,
+		 * this describes the request from the proxy. When there is no
+		 * proxy, this will have exactly the same value as `flags`. */
+		struct kr_request_qsource_flags comm_flags;
+		size_t size; /**< query packet size */
+		int32_t stream_id; /**< HTTP/2 stream ID for DoH requests */
+		kr_http_header_array_t headers;  /**< HTTP/2 headers for DoH requests */
+	} qsource;
+	struct {
+		unsigned rtt;                  /**< Current upstream RTT */
+		const struct kr_transport *transport;   /**< Current upstream transport */
+	} upstream;                        /**< Upstream information, valid only in consume() phase */
+	struct kr_qflags options;
+	int state;
+	ranked_rr_array_t answ_selected;
+	ranked_rr_array_t auth_selected;
+	ranked_rr_array_t add_selected;
+	bool answ_validated; /**< internal to validator; beware of caching, etc. */
+	bool auth_validated; /**< see answ_validated ^^ ; TODO */
+
+	/** Overall rank for the request.
+	 *
+	 * Values from kr_rank, currently just KR_RANK_SECURE and _INITIAL.
+	 * Only read this in finish phase and after validator, please.
+	 * Meaning of _SECURE: all RRs in answer+authority are _SECURE,
+	 *   including any negative results implied (NXDOMAIN, NODATA).
+	 */
+	uint8_t rank;
+
+	struct kr_rplan rplan;
+	trace_log_f trace_log; /**< Logging tracepoint */
+	trace_callback_f trace_finish; /**< Request finish tracepoint */
+	int vars_ref; /**< Reference to per-request variable table. LUA_NOREF if not set. */
+	knot_mm_t pool;
+	unsigned int uid; /**< for logging purposes only */
+	struct {
+		addr_info_f is_tls_capable;
+		addr_info_f is_tcp_connected;
+		addr_info_f is_tcp_waiting;
+		kr_sockaddr_array_t forwarding_targets; /**< When forwarding, possible targets are put here */
+	} selection_context;
+	unsigned int count_no_nsaddr;
+	unsigned int count_fail_row;
+	alloc_wire_f alloc_wire_cb; /**< CB to allocate answer wire (can be NULL). */
+	struct kr_extended_error extended_error;  /**< EDE info; don't modify directly, use kr_request_set_extended_error() */
+};
+
+/** Initializer for an array of *_selected. */
+#define kr_request_selected(req) { \
+	[KNOT_ANSWER] = &(req)->answ_selected, \
+	[KNOT_AUTHORITY] = &(req)->auth_selected, \
+	[KNOT_ADDITIONAL] = &(req)->add_selected, \
+	}
+
+/**
+ * Begin name resolution.
+ *
+ * @note Expects a request to have an initialized mempool.
+ *
+ * @param request request state with initialized mempool
+ * @param ctx     resolution context
+ * @return        CONSUME (expecting query)
+ */
+KR_EXPORT
+int kr_resolve_begin(struct kr_request *request, struct kr_context *ctx);
+
+/**
+ * Ensure that request->answer->opt_rr is present if query has EDNS.
+ *
+ * This function should be used after clearing a response packet to ensure its
+ * opt_rr is properly set. Returns the opt_rr (for convenience) or NULL.
+ */
+KR_EXPORT
+knot_rrset_t * kr_request_ensure_edns(struct kr_request *request);
+
+/**
+ * Ensure that request->answer is usable, and return it (for convenience).
+ *
+ * It may return NULL, in which case it marks ->state with _FAIL and no answer will be sent.
+ * Only use this when it's guaranteed that there will be no delay before sending it.
+ * You don't need to call this in places where "resolver knows" that there will be no delay,
+ * but even there you need to check if the ->answer is NULL (unless you check for _FAIL anyway).
+ */
+KR_EXPORT
+knot_pkt_t * kr_request_ensure_answer(struct kr_request *request);
+
+/**
+ * Consume input packet (may be either first query or answer to query originated from kr_resolve_produce())
+ *
+ * @note If the I/O fails, provide an empty or NULL packet, this will make iterator recognize nameserver failure.
+ *
+ * @param  request request state (awaiting input)
+ * @param  src     [in] packet source address
+ * @param  packet  [in] input packet
+ * @return         any state
+ */
+KR_EXPORT
+int kr_resolve_consume(struct kr_request *request, struct kr_transport **transport, knot_pkt_t *packet);
+
+/**
+ * Produce either next additional query or finish.
+ *
+ * If the CONSUME is returned then dst, type and packet will be filled with
+ * appropriate values and caller is responsible to send them and receive answer.
+ * If it returns any other state, then content of the variables is undefined.
+ *
+ * @param  request request state (in PRODUCE state)
+ * @param  dst     [out] possible address of the next nameserver
+ * @param  type    [out] possible used socket type (SOCK_STREAM, SOCK_DGRAM)
+ * @param  packet  [out] packet to be filled with additional query
+ * @return         any state
+ */
+KR_EXPORT
+int kr_resolve_produce(struct kr_request *request, struct kr_transport **transport, knot_pkt_t *packet);
+
+/**
+ * Finalises the outbound query packet with the knowledge of the IP addresses.
+ *
+ * @note The function must be called before actual sending of the request packet.
+ *
+ * @param  request request state (in PRODUCE state)
+ * @param  src     address from which the query is going to be sent
+ * @param  dst     address of the name server
+ * @param  type    used socket type (SOCK_STREAM, SOCK_DGRAM)
+ * @param  packet  [in,out] query packet to be finalised
+ * @return         kr_ok() or error code
+ */
+KR_EXPORT
+int kr_resolve_checkout(struct kr_request *request, const struct sockaddr *src,
+                        struct kr_transport *transport, knot_pkt_t *packet);
+
+/**
+ * Finish resolution and commit results if the state is DONE.
+ *
+ * @note The structures will be deinitialized, but the assigned memory pool is not going to
+ *       be destroyed, as it's owned by caller.
+ *
+ * @param  request request state
+ * @param  state   either DONE or FAIL state (to be assigned to request->state)
+ * @return         DONE
+ */
+KR_EXPORT
+int kr_resolve_finish(struct kr_request *request, int state);
+
+/**
+ * Return resolution plan.
+ * @param  request request state
+ * @return         pointer to rplan
+ */
+KR_EXPORT KR_PURE
+struct kr_rplan *kr_resolve_plan(struct kr_request *request);
+
+/**
+ * Return memory pool associated with request.
+ * @param  request request state
+ * @return         mempool
+ */
+KR_EXPORT KR_PURE
+knot_mm_t *kr_resolve_pool(struct kr_request *request);
+
+/**
+ * Set the extended DNS error for request.
+ *
+ * The error is set only if it has a higher or the same priority as the one
+ * already assigned.  The provided extra_text may be NULL, or a string that is
+ * allocated either statically, or on the request's mempool. To clear any
+ * error, call it with KNOT_EDNS_EDE_NONE and NULL as extra_text.
+ *
+ * To facilitate debugging, we include a unique base32 identifier at the start
+ * of the extra_text field for every call of this function. To generate such an
+ * identifier, you can use the command:
+ * $ base32 /dev/random | head -c 4
+ *
+ * @param  request     request state
+ * @param  info_code   extended DNS error code
+ * @param  extra_text  optional string with additional information
+ * @return             info_code that is set after the call
+ */
+KR_EXPORT
+int kr_request_set_extended_error(struct kr_request *request, int info_code, const char *extra_text);
+
+static inline void kr_query_inform_timeout(struct kr_request *req, const struct kr_query *qry)
+{
+	kr_request_set_extended_error(req, KNOT_EDNS_EDE_NREACH_AUTH, "RRPF");
+
+	unsigned ind = 0;
+	for (const struct kr_query *q = qry; q; q = q->parent)
+		ind += 2;
+	const uint32_t qid = qry ? qry->uid : 0;
+
+	kr_log_req(req, qid, ind, WORKER, "internal timeout for resolving the request has expired\n");
+}