--- /dev/null
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#pragma once
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <isc/buffer.h>
+#include <isc/mem.h>
+#include <isc/region.h>
+#include <isc/util.h>
+
+#define ISC_DNSBUFFER_STATIC_BUFFER_SIZE (512)
+#define ISC_DNSBUFFER_INITIAL_DYNAMIC_BUFFER_SIZE (ISC_BUFFER_INCR * 2)
+
+typedef struct isc_dnsbuffer {
+ isc_buffer_t *current; /* pointer to the currently used buffer */
+ isc_buffer_t stbuf; /* static memory buffer */
+ uint8_t buf[ISC_DNSBUFFER_STATIC_BUFFER_SIZE]; /* storage for the static
+ buffer */
+ isc_buffer_t *dynbuf; /* resizeable dynamic memory buffer */
+ isc_mem_t *mctx;
+} isc_dnsbuffer_t;
+/*
+ * The 'isc_dnsbuffer_t' object implementation is a thin wrapper on
+ * top of 'isc_buffer_t' which has the following characteristics:
+ *
+ * - provides interface specifically atuned for handling/generating
+ * DNS messages, especially in the format used for DNS messages over
+ * TCP;
+ *
+ * - avoids allocating dynamic memory when handling small DNS
+ * messages, while transparently switching to using dynamic memory
+ * when handling larger messages. This approach significantly
+ * reduces pressure on the memory allocator, as most of the DNS
+ * messages are small.
+ */
+
+static inline void
+isc_dnsbuffer_init(isc_dnsbuffer_t *restrict dnsbuf, isc_mem_t *memctx);
+/*!<
+ * \brief Initialise the 'isc_dnsbuffer_t' object, keep a reference to
+ * 'memctx' inside the object.
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL;
+ *\li 'memctx' is not NULL.
+ */
+
+static inline void
+isc_dnsbuffer_uninit(isc_dnsbuffer_t *restrict dnsbuf);
+/*!<
+ * \brief Un-initialise the 'isc_dnsbuffer_t' object, de-allocate any
+ *dynamically allocated memory, detach from an internal memory context
+ * reference.
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL.
+ */
+
+static inline isc_dnsbuffer_t *
+isc_dnsbuffer_new(isc_mem_t *memctx);
+/*!<
+ * \brief Allocate and initialise a new 'isc_dnsbuffer_t' object, keep a
+ * reference to 'memctx' inside the object.
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL;
+ *\li 'memctx' is not NULL.
+ */
+
+static inline void
+isc_dnsbuffer_free(isc_dnsbuffer_t **restrict pdnsbuf);
+/*!<
+ * \brief Un-initialise and de-allocate the given 'isc_dnsbuffer_t' object.
+ *
+ * Requires:
+ *\li 'pdnsbuf' is not NULL;
+ *\li 'pdnsbuf' does not point to NULL.
+ */
+
+static inline void
+isc_dnsbuffer_clear(isc_dnsbuffer_t *restrict dnsbuf);
+/*!<
+ * \brief Clear the given 'isc_dnsbuffer_t' object (make it empty).
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL.
+ */
+
+static inline unsigned int
+isc_dnsbuffer_length(const isc_dnsbuffer_t *restrict dnsbuf);
+/*!<
+ * \brief Return the total length of the internal memory buffer of
+ * the given 'isc_dnsbuffer_t' object.
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL.
+ */
+
+static inline unsigned int
+isc_dnsbuffer_usedlength(const isc_dnsbuffer_t *restrict dnsbuf);
+/*!<
+ * \brief Return the total number of used bytes from the internal
+ * memory buffer of the given 'isc_dnsbuffer_t' object.
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL.
+ */
+
+static inline unsigned int
+isc_dnsbuffer_remaininglength(const isc_dnsbuffer_t *restrict dnsbuf);
+/*!<
+ * \brief Return the total number of remaining (unprocessed data)
+ * bytes from the internal memory buffer of the given
+ * 'isc_dnsbuffer_t' object.
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL.
+ */
+
+static inline void
+isc_dnsbuffer_remainingregion(const isc_dnsbuffer_t *restrict dnsbuf,
+ isc_region_t *region);
+/*!<
+ * \brief Make the given 'isc_region_t' object reference remaining
+ * (unprocessed) data from the internal memory buffer of the given
+ * 'isc_dnsbuffer_t' object.
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL.
+ */
+
+static inline void
+isc_dnsbuffer_compact(const isc_dnsbuffer_t *restrict dnsbuf);
+/*!<
+ * \brief Compact the internal used memory region of the internal
+ * memory buffer of the given 'isc_dnsbuffer_t' object so that it
+ * occurs at the start of the memory buffer. Then used region is
+ * shrunk by the size of the processed (consumed) region, and the
+ * consumed region is then made empty. This way the previously
+ * processed (consumed) amount of memory can be used again without
+ * resizing/reallocating the buffer.
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL.
+ */
+
+static inline bool
+isc_dnsbuffer_trycompact(const isc_dnsbuffer_t *restrict dnsbuf);
+/*!<
+ * \brief Compact the internal used memory region of the internal
+ * memory buffer of the given 'isc_dnsbuffer_t' object in the case
+ * when the processed (consumed) region is larger or equal in size to
+ * the unprocessed one.
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL.
+ */
+
+static inline void
+isc_dnsbuffer_consume(isc_dnsbuffer_t *restrict dnsbuf, const unsigned int n);
+/*!<
+ * \brief Consume the given number of bytes from the beginning of
+ * the unprocessed data region of the given 'isc_dnsbuffer_t' object.
+ * The call moves the 'current' unprocessed data region pointer by the
+ * given number of bytes.
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL.
+ */
+
+static inline void
+isc_dnsbuffer_putmem(isc_dnsbuffer_t *restrict dnsbuf, void *buf,
+ const unsigned int buf_size);
+/*!<
+ * \brief Copy 'buf_size' bytes from the location pointed to by
+ * 'buf' pointer to the end of the unprocessed data region of the
+ * given 'isc_dnsbuffer_t' object. Resize/reallocate the internal
+ * memory buffer if it is too small.
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL;
+ *\li 'buf' is not NULL;
+ *\li 'buf_size' is greater than '0'.
+ */
+
+static inline uint8_t *
+isc_dnsbuffer_current(const isc_dnsbuffer_t *restrict dnsbuf);
+/*!<
+ * \brief Return the pointer to the beginning of unprocessed data
+ * region of the given 'isc_dnsbuffer_t' object ("current pointer").
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL.
+ */
+
+static inline uint16_t
+isc_dnsbuffer_peek_uint16be(const isc_dnsbuffer_t *restrict dnsbuf);
+/*!<
+ * \brief Lookup an unsigned short (16-bit) value in
+ * big-endian/network byte order at the beginning of unprocessed data
+ * region of the given 'isc_dnsbuffer_t' object.
+ *
+ * If there is not enough data available in the region, '0' will be
+ * returned.
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL.
+ */
+
+static inline uint16_t
+isc_dnsbuffer_consume_uint16be(isc_dnsbuffer_t *restrict dnsbuf);
+/*!<
+ * \brief Read an unsigned short (16-bit) value in
+ * big-endian/network byte order at the beginning of unprocessed data
+ * region of the given 'isc_dnsbuffer_t' object.
+ *
+ * If there is not enough data available in the region, '0' will be
+ * returned.
+ *
+ * In the case, when the data has been read successfully, the start of
+ * the unprocessed data region is advanced by two bytes.
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL.
+ */
+
+static inline void
+isc_dnsbuffer_putmem_uint16be(isc_dnsbuffer_t *restrict dnsbuf,
+ const uint16_t v);
+/*!<
+ * \brief Append a given unsigned short (16-bit) value 'v' converted
+ * into big-endian/network byte order at the end of unprocessed data
+ * region of the given 'isc_dnsbuffer_t' object. Resize/reallocate the
+ * internal memory buffer if it is too small to hold the appended data.
+ *
+ * Requires:
+ *\li 'dnsbuf' is not NULL.
+ */
+
+static inline void
+isc_dnsbuffer_init(isc_dnsbuffer_t *restrict dnsbuf, isc_mem_t *memctx) {
+ REQUIRE(dnsbuf != NULL);
+ REQUIRE(memctx != NULL);
+ *dnsbuf = (isc_dnsbuffer_t){ .current = &dnsbuf->stbuf };
+ isc_buffer_init(&dnsbuf->stbuf, &dnsbuf->buf[0], sizeof(dnsbuf->buf));
+ isc_mem_attach(memctx, &dnsbuf->mctx);
+}
+
+static inline void
+isc_dnsbuffer_uninit(isc_dnsbuffer_t *restrict dnsbuf) {
+ REQUIRE(dnsbuf != NULL);
+ isc_buffer_clear(&dnsbuf->stbuf);
+ if (dnsbuf->dynbuf != NULL) {
+ isc_buffer_free(&dnsbuf->dynbuf);
+ }
+
+ if (dnsbuf->mctx != NULL) {
+ isc_mem_detach(&dnsbuf->mctx);
+ }
+}
+
+static inline isc_dnsbuffer_t *
+isc_dnsbuffer_new(isc_mem_t *memctx) {
+ isc_dnsbuffer_t *newbuf;
+
+ REQUIRE(memctx != NULL);
+
+ newbuf = isc_mem_get(memctx, sizeof(*newbuf));
+ isc_dnsbuffer_init(newbuf, memctx);
+
+ return (newbuf);
+}
+
+static inline void
+isc_dnsbuffer_free(isc_dnsbuffer_t **restrict pdnsbuf) {
+ isc_dnsbuffer_t *restrict buf = NULL;
+ isc_mem_t *memctx = NULL;
+ REQUIRE(pdnsbuf != NULL && *pdnsbuf != NULL);
+
+ buf = *pdnsbuf;
+
+ isc_mem_attach(buf->mctx, &memctx);
+ isc_dnsbuffer_uninit(buf);
+ isc_mem_putanddetach(&memctx, buf, sizeof(*buf));
+
+ *pdnsbuf = NULL;
+}
+
+static inline void
+isc_dnsbuffer_clear(isc_dnsbuffer_t *restrict dnsbuf) {
+ REQUIRE(dnsbuf != NULL);
+ isc_buffer_clear(dnsbuf->current);
+}
+
+static inline unsigned int
+isc_dnsbuffer_length(const isc_dnsbuffer_t *restrict dnsbuf) {
+ REQUIRE(dnsbuf != NULL);
+ return (isc_buffer_length(dnsbuf->current));
+}
+
+static inline unsigned int
+isc_dnsbuffer_usedlength(const isc_dnsbuffer_t *restrict dnsbuf) {
+ REQUIRE(dnsbuf != NULL);
+ return (isc_buffer_usedlength(dnsbuf->current));
+}
+
+static inline unsigned int
+isc_dnsbuffer_remaininglength(const isc_dnsbuffer_t *restrict dnsbuf) {
+ REQUIRE(dnsbuf != NULL);
+ return (isc_buffer_remaininglength(dnsbuf->current));
+}
+
+static inline void
+isc_dnsbuffer_remainingregion(const isc_dnsbuffer_t *restrict dnsbuf,
+ isc_region_t *region) {
+ REQUIRE(dnsbuf != NULL);
+ REQUIRE(region != NULL);
+ isc_buffer_remainingregion(dnsbuf->current, region);
+}
+
+static inline void
+isc_dnsbuffer_compact(const isc_dnsbuffer_t *restrict dnsbuf) {
+ REQUIRE(dnsbuf != NULL);
+ isc_buffer_compact(dnsbuf->current);
+}
+
+static inline bool
+isc_dnsbuffer_trycompact(const isc_dnsbuffer_t *restrict dnsbuf) {
+ REQUIRE(dnsbuf != NULL);
+ if (isc_buffer_consumedlength(dnsbuf->current) >=
+ isc_dnsbuffer_remaininglength(dnsbuf))
+ {
+ isc_dnsbuffer_compact(dnsbuf);
+ return (true);
+ }
+
+ return (false);
+}
+
+static inline void
+isc_dnsbuffer_consume(isc_dnsbuffer_t *restrict dnsbuf, const unsigned int n) {
+ REQUIRE(dnsbuf != NULL);
+ isc_buffer_forward(dnsbuf->current, n);
+}
+
+static inline void
+isc_dnsbuffer_putmem(isc_dnsbuffer_t *restrict dnsbuf, void *buf,
+ const unsigned int buf_size) {
+ REQUIRE(dnsbuf != NULL);
+ REQUIRE(buf != NULL);
+ REQUIRE(buf_size > 0);
+ if (!(dnsbuf->current == &dnsbuf->stbuf &&
+ isc_buffer_availablelength(dnsbuf->current) >= buf_size) &&
+ dnsbuf->dynbuf == NULL)
+ {
+ isc_region_t remaining = { 0 };
+ unsigned int total_size = 0;
+
+ isc_buffer_remainingregion(&dnsbuf->stbuf, &remaining);
+ total_size = remaining.length + buf_size;
+ if (total_size < ISC_DNSBUFFER_INITIAL_DYNAMIC_BUFFER_SIZE) {
+ total_size = ISC_DNSBUFFER_INITIAL_DYNAMIC_BUFFER_SIZE;
+ }
+ isc_buffer_allocate(dnsbuf->mctx, &dnsbuf->dynbuf, total_size);
+ isc_buffer_setautorealloc(dnsbuf->dynbuf, true);
+ if (remaining.length > 0) {
+ isc_buffer_putmem(dnsbuf->dynbuf, remaining.base,
+ remaining.length);
+ }
+
+ dnsbuf->current = dnsbuf->dynbuf;
+ }
+
+ isc_buffer_putmem(dnsbuf->current, buf, buf_size);
+}
+
+static inline uint8_t *
+isc_dnsbuffer_current(const isc_dnsbuffer_t *restrict dnsbuf) {
+ REQUIRE(dnsbuf != NULL);
+ return (isc_buffer_current(dnsbuf->current));
+}
+
+static inline uint16_t
+isc__dnsbuffer_peek_uint16be(const isc_dnsbuffer_t *restrict dnsbuf) {
+ uint16_t v;
+ uint8_t *p = (uint8_t *)isc_dnsbuffer_current(dnsbuf);
+
+ v = p[0] << 8;
+ v |= p[1] & 0xFF;
+
+ return (v);
+}
+
+static inline uint16_t
+isc_dnsbuffer_peek_uint16be(const isc_dnsbuffer_t *restrict dnsbuf) {
+ REQUIRE(dnsbuf != NULL);
+ if (isc_dnsbuffer_remaininglength(dnsbuf) < sizeof(uint16_t)) {
+ return (0);
+ }
+
+ return (isc__dnsbuffer_peek_uint16be(dnsbuf));
+}
+
+static inline uint16_t
+isc_dnsbuffer_consume_uint16be(isc_dnsbuffer_t *restrict dnsbuf) {
+ uint16_t v;
+
+ REQUIRE(dnsbuf != NULL);
+
+ if (isc_dnsbuffer_remaininglength(dnsbuf) < sizeof(uint16_t)) {
+ return (0);
+ }
+
+ v = isc__dnsbuffer_peek_uint16be(dnsbuf);
+
+ isc_dnsbuffer_consume(dnsbuf, sizeof(uint16_t));
+
+ return (v);
+}
+
+static inline void
+isc_dnsbuffer_putmem_uint16be(isc_dnsbuffer_t *restrict dnsbuf,
+ const uint16_t v) {
+ uint8_t b[2] = { 0 };
+
+ REQUIRE(dnsbuf != NULL);
+
+ b[0] = v >> 8;
+ b[1] = v & 0xFF;
+
+ isc_dnsbuffer_putmem(dnsbuf, b, sizeof(b));
+}
projects / thirdparty / bind9.git / commitdiff
