Adding upstream version 2.7.6.upstream/2.7.6upstream

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

1 files changed, 402 insertions, 0 deletions

diff --git a/src/libknot/packet/pkt.h b/src/libknot/packet/pkt.h
new file mode 100644
index 0000000..a105d9f
--- /dev/null
+++ b/src/libknot/packet/pkt.h
@@ -0,0 +1,402 @@
+/*  Copyright (C) 2018 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+/*!
+ * \file
+ *
+ * \brief Structure for holding DNS packet data and metadata.
+ *
+ * \addtogroup pkt
+ * @{
+ */
+
+#pragma once
+
+#include <assert.h>
+#include <stdint.h>
+
+#include "libknot/consts.h"
+#include "libknot/dname.h"
+#include "libknot/mm_ctx.h"
+#include "libknot/rrset.h"
+#include "libknot/rrtype/opt.h"
+#include "libknot/packet/wire.h"
+#include "libknot/packet/compr.h"
+#include "libknot/wire.h"
+
+/* Number of packet sections (ANSWER, AUTHORITY, ADDITIONAL). */
+#define KNOT_PKT_SECTIONS 3
+
+/*!
+ * \brief Packet flags.
+ */
+enum {
+	KNOT_PF_NULL      = 0 << 0, /*!< No flags. */
+	KNOT_PF_FREE      = 1 << 1, /*!< Free with packet. */
+	KNOT_PF_NOTRUNC   = 1 << 2, /*!< Don't truncate. */
+	KNOT_PF_CHECKDUP  = 1 << 3, /*!< Check for duplicates. */
+	KNOT_PF_KEEPWIRE  = 1 << 4, /*!< Keep wireformat untouched when parsing. */
+	KNOT_PF_NOCANON   = 1 << 5, /*!< Don't canonicalize rrsets during parsing. */
+	KNOT_PF_ORIGTTL   = 1 << 6, /*!< Write RRSIGs with their original TTL. */
+};
+
+typedef struct knot_pkt knot_pkt_t;
+
+/*!
+ * \brief Packet section.
+ * Points to RRSet and RRSet info arrays in the packet.
+ * This structure is required for random access to packet sections.
+ */
+typedef struct {
+	knot_pkt_t *pkt; /*!< Owner. */
+	uint16_t pos;    /*!< Position in the rr/rrinfo fields in packet. */
+	uint16_t count;  /*!< Number of RRSets in this section. */
+} knot_pktsection_t;
+
+/*!
+ * \brief Structure representing a DNS packet.
+ */
+struct knot_pkt {
+	uint8_t *wire;         /*!< Wire format of the packet. */
+	size_t size;           /*!< Current wire size of the packet. */
+	size_t max_size;       /*!< Maximum allowed size of the packet. */
+	size_t parsed;         /*!< Parsed size. */
+	uint16_t reserved;     /*!< Reserved space. */
+	uint16_t qname_size;   /*!< QNAME size. */
+	uint16_t rrset_count;  /*!< Packet RRSet count. */
+	uint16_t flags;        /*!< Packet flags. */
+
+	knot_rrset_t *opt_rr;   /*!< OPT RR included in the packet. */
+	knot_rrset_t *tsig_rr;  /*!< TSIG RR stored in the packet. */
+
+	/*! EDNS option positions in the wire (if parsed from wire). */
+	knot_edns_options_t *edns_opts;
+
+	/*! TSIG RR position in the wire (if parsed from wire). */
+	struct {
+		uint8_t *pos;
+		size_t len;
+	} tsig_wire;
+
+	/* Packet sections. */
+	knot_section_t current;
+	knot_pktsection_t sections[KNOT_PKT_SECTIONS];
+
+	/* Packet RRSet (meta)data. */
+	size_t rrset_allocd;
+	knot_rrinfo_t *rr_info;
+	knot_rrset_t *rr;
+
+	knot_mm_t mm; /*!< Memory allocation context. */
+
+	knot_compr_t compr; /*!< Compression context. */
+};
+
+/*!
+ * \brief Create new packet over existing memory, or allocate new from memory context.
+ *
+ * \note Packet is allocated from given memory context.
+ *
+ * \param wire If NULL, memory of 'len' size shall be allocated.
+ *        Otherwise pointer is used for the wire format of the packet.
+ * \param len Wire format length.
+ * \param mm Memory context (NULL for default).
+ * \return New packet or NULL.
+ */
+knot_pkt_t *knot_pkt_new(void *wire, uint16_t len, knot_mm_t *mm);
+
+/*!
+ * \brief Copy packet.
+ *
+ * \note Current implementation is not very efficient, as it re-parses the wire.
+ *
+ * \param dst Target packet.
+ * \param src Source packet.
+ *
+ * \return new packet or NULL
+ */
+int knot_pkt_copy(knot_pkt_t *dst, const knot_pkt_t *src);
+
+/*!
+ * \brief Initialized response from query packet.
+ *
+ * \note Question is not checked, it is expected to be checked already.
+ *
+ * \param pkt Given packet.
+ * \param query Query.
+ * \return KNOT_EOK, KNOT_EINVAL, KNOT_ESPACE
+ */
+int knot_pkt_init_response(knot_pkt_t *pkt, const knot_pkt_t *query);
+
+/*! \brief Reinitialize packet for another use. */
+void knot_pkt_clear(knot_pkt_t *pkt);
+
+/*! \brief Begone you foul creature of the underworld. */
+void knot_pkt_free(knot_pkt_t *pkt);
+
+/*!
+ * \brief Reserve an arbitrary amount of space in the packet.
+ *
+ * \return KNOT_EOK
+ * \return KNOT_ERANGE if size can't be reserved
+ */
+int knot_pkt_reserve(knot_pkt_t *pkt, uint16_t size);
+
+/*!
+ * \brief Reclaim reserved size.
+ *
+ * \return KNOT_EOK
+ * \return KNOT_ERANGE if size can't be reclaimed
+ */
+int knot_pkt_reclaim(knot_pkt_t *pkt, uint16_t size);
+
+/*
+ * Packet QUESTION accessors.
+ */
+static inline uint16_t knot_pkt_question_size(const knot_pkt_t *pkt)
+{
+	if (pkt == NULL || pkt->qname_size == 0) {
+		return 0;
+	}
+
+	return pkt->qname_size + 2 * sizeof(uint16_t);
+}
+
+static inline knot_dname_t *knot_pkt_qname(const knot_pkt_t *pkt)
+{
+	if (pkt == NULL || pkt->qname_size == 0) {
+		return NULL;
+	}
+
+	return pkt->wire + KNOT_WIRE_HEADER_SIZE;
+}
+
+static inline uint16_t knot_pkt_qtype(const knot_pkt_t *pkt)
+{
+	if (pkt == NULL || pkt->qname_size == 0) {
+		return 0;
+	}
+
+	unsigned off = KNOT_WIRE_HEADER_SIZE + pkt->qname_size;
+	return knot_wire_read_u16(pkt->wire + off);
+}
+
+static inline uint16_t knot_pkt_qclass(const knot_pkt_t *pkt)
+{
+	if (pkt == NULL || pkt->qname_size == 0) {
+		return 0;
+	}
+
+	unsigned off = KNOT_WIRE_HEADER_SIZE + pkt->qname_size + sizeof(uint16_t);
+	return knot_wire_read_u16(pkt->wire + off);
+}
+
+/*
+ * Packet writing API.
+ */
+
+/*!
+ * \brief Begin reading/writing packet section.
+ *
+ * \note You must proceed in the natural order (ANSWER, AUTHORITY, ADDITIONAL).
+ *
+ * \param pkt
+ * \param section_id
+ * \return KNOT_EOK or KNOT_EINVAL
+ */
+int knot_pkt_begin(knot_pkt_t *pkt, knot_section_t section_id);
+
+/*!
+ * \brief Put QUESTION in the packet.
+ *
+ * \note Since we support QD=1 only, QUESTION is a special type of packet section.
+ * \note Must not be used after putting RRsets into the packet.
+ *
+ * \param pkt
+ * \param qname
+ * \param qclass
+ * \param qtype
+ * \return KNOT_EOK or various errors
+ */
+int knot_pkt_put_question(knot_pkt_t *pkt, const knot_dname_t *qname,
+                          uint16_t qclass, uint16_t qtype);
+
+/*!
+ * \brief Put RRSet into packet.
+ *
+ * \note See compr.h for description on how compression hints work.
+ * \note Available flags: PF_FREE, KNOT_PF_CHECKDUP, KNOT_PF_NOTRUNC
+ *
+ * \param pkt
+ * \param compr_hint  Compression hint, see enum knot_compr_hint or absolute
+ *                    position.
+ * \param rr          Given RRSet.
+ * \param rotate      Rotate the RRSet order by this count.
+ * \param flags       RRSet flags (set PF_FREE if you want RRSet to be freed
+ *                    with the packet).
+ *
+ * \return KNOT_EOK, KNOT_ESPACE, various errors
+ */
+int knot_pkt_put_rotate(knot_pkt_t *pkt, uint16_t compr_hint, const knot_rrset_t *rr,
+                        uint16_t rotate, uint16_t flags);
+
+/*! \brief Same as knot_pkt_put_rotate but without rrset rotation. */
+static inline int knot_pkt_put(knot_pkt_t *pkt, uint16_t compr_hint,
+                               const knot_rrset_t *rr, uint16_t flags)
+{
+	return knot_pkt_put_rotate(pkt, compr_hint, rr, 0, flags);
+}
+
+/*! \brief Get description of the given packet section. */
+static inline const knot_pktsection_t *knot_pkt_section(const knot_pkt_t *pkt,
+                                                        knot_section_t section_id)
+{
+	assert(pkt);
+	return &pkt->sections[section_id];
+}
+
+/*! \brief Get RRSet from the packet section. */
+static inline const knot_rrset_t *knot_pkt_rr(const knot_pktsection_t *section,
+                                              uint16_t i)
+{
+	assert(section);
+	return section->pkt->rr + section->pos + i;
+}
+
+/*! \brief Get RRSet offset in the packet wire. */
+static inline uint16_t knot_pkt_rr_offset(const knot_pktsection_t *section,
+                                          uint16_t i)
+{
+	assert(section);
+	return section->pkt->rr_info[section->pos + i].pos;
+}
+
+/*
+ * Packet parsing API.
+ */
+
+/*!
+ * \brief Parse both packet question and payload.
+ *
+ * Parses both QUESTION and all packet sections,
+ * includes semantic checks over specific RRs (TSIG, OPT).
+ *
+ * \note If KNOT_PF_KEEPWIRE is set, TSIG RR is not stripped from the wire
+ *       and is processed as any other RR.
+ *
+ * \param  pkt Given packet.
+ * \param  flags Parsing flags (allowed KNOT_PF_KEEPWIRE)
+ *
+ * \retval KNOT_EOK if success.
+ * \retval KNOT_ETRAIL if success but with some trailing data.
+ * \retval KNOT_EMALF and other errors.
+ */
+int knot_pkt_parse(knot_pkt_t *pkt, unsigned flags);
+
+/*!
+ * \brief Parse packet header and a QUESTION section.
+ */
+int knot_pkt_parse_question(knot_pkt_t *pkt);
+
+/*!
+ * \brief Get packet extended RCODE.
+ *
+ * Extended RCODE is created by considering TSIG RCODE, EDNS RCODE and
+ * DNS Header RCODE. (See RFC 6895, Section 2.3).
+ *
+ * \param pkt Packet to get the response code from.
+ *
+ * \return Whole extended RCODE (0 if pkt == NULL).
+ */
+uint16_t knot_pkt_ext_rcode(const knot_pkt_t *pkt);
+
+/*!
+ * \brief Get packet extended RCODE name.
+ *
+ * The packet parameter is important as the name depends on TSIG.
+ *
+ * \param pkt Packet to get the response code from.
+ *
+ * \return RCODE name (or empty string if not known).
+ */
+const char *knot_pkt_ext_rcode_name(const knot_pkt_t *pkt);
+
+/*!
+ * \brief Checks if there is an OPT RR in the packet.
+ */
+static inline bool knot_pkt_has_edns(const knot_pkt_t *pkt)
+{
+	assert(pkt);
+	return pkt->opt_rr != NULL;
+}
+
+/*!
+ * \brief Checks if TSIG is present.
+ */
+static inline bool knot_pkt_has_tsig(const knot_pkt_t *pkt)
+{
+	assert(pkt);
+	return pkt->tsig_rr != NULL;
+}
+
+/*!
+ * \brief Checks if DO bit is set in the packet's OPT RR.
+ */
+static inline bool knot_pkt_has_dnssec(const knot_pkt_t *pkt)
+{
+	assert(pkt);
+	return knot_pkt_has_edns(pkt) && knot_edns_do(pkt->opt_rr);
+}
+
+/*!
+ * \brief Get specific EDNS option from a parsed packet.
+ */
+static inline uint8_t *knot_pkt_edns_option(const knot_pkt_t *pkt, uint16_t code)
+{
+	assert(pkt);
+	if (pkt->edns_opts != NULL && code <= KNOT_EDNS_MAX_OPTION_CODE) {
+		return pkt->edns_opts->ptr[code];
+	} else {
+		return NULL;
+	}
+}
+
+/*!
+ * \brief Computes a reasonable Padding data length for a given packet and opt RR.
+ *
+ * \param pkt     DNS Packet prepared and otherwise ready to go, no OPT yet added.
+ * \param opt_rr  OPT RR, not yet including padding.
+ *
+ * \return Required padding length or -1 if padding not required.
+ */
+static inline int knot_pkt_default_padding_size(const knot_pkt_t *pkt,
+                                                const knot_rrset_t *opt_rr)
+{
+	if (knot_wire_get_qr(pkt->wire)) {
+		return knot_edns_alignment_size(pkt->size, knot_rrset_size(opt_rr),
+		                                KNOT_EDNS_ALIGNMENT_RESPONSE_DEFAULT);
+	} else {
+		return knot_edns_alignment_size(pkt->size, knot_rrset_size(opt_rr),
+		                                KNOT_EDNS_ALIGNMENT_QUERY_DEFALT);
+	}
+}
+
+static inline size_t knot_pkt_size(const knot_pkt_t *pkt)
+{
+	assert(pkt);
+	return pkt->size + (knot_pkt_has_tsig(pkt) ? pkt->tsig_wire.len : 0);
+}
+
+/*! @} */