254 lines
7.4 KiB
C
254 lines
7.4 KiB
C
/** @file
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* @brief Buffer management.
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*/
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/*
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* Copyright (c) 2015 Intel Corporation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef __NET_BUF_H
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#define __NET_BUF_H
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#include <stddef.h>
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#include <stdint.h>
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#include <toolchain.h>
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#include <misc/util.h>
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#include <nanokernel.h>
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/* Alignment needed for various parts of the buffer definition */
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#define __net_buf_align __aligned(sizeof(int))
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struct net_buf {
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/** FIFO uses first 4 bytes itself, reserve space */
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int __unused;
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/** Size of the user data associated with this buffer. */
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const uint16_t user_data_size;
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/** Reference count. */
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uint8_t ref;
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/** Pointer to the start of data in the buffer. */
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uint8_t *data;
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/** Length of the data behind the data pointer. */
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uint16_t len;
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/** Amount of data that this buffer can store. */
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const uint16_t size;
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/** Where the buffer should go when freed up. */
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struct nano_fifo * const free;
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/** Function to be called when the buffer is freed. */
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void (*const destroy)(struct net_buf *buf);
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/** Start of the data storage. Not to be accessed directly
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* (the data pointer should be used instead).
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*/
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uint8_t __buf[0] __net_buf_align;
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};
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/** @brief Define a pool of buffers of a certain amount and size.
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*
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* Defines the necessary memory space (array of structs) for the needed
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* amount of buffers. After this the net_buf_pool_init() API still
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* needs to be used (at runtime), after which the buffers can be
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* accessed using the fifo given as one of the parameters.
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*
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* If provided with a custom destroy callback this callback is
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* responsible for eventually returning the buffer back to the free
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* buffers FIFO through nano_fifo_put(buf->free, buf).
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*
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* @param _name Name of buffer pool.
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* @param _count Number of buffers in the pool.
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* @param _size Maximum data size for each buffer.
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* @param _fifo FIFO for the buffers when they are unused.
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* @param _destroy Optional destroy callback when buffer is freed.
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* @param _ud_size Amount of user data space to reserve.
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*/
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#define NET_BUF_POOL(_name, _count, _size, _fifo, _destroy, _ud_size) \
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struct { \
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struct net_buf buf; \
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uint8_t data[ROUND_UP(_size, 4)] __net_buf_align; \
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uint8_t ud[ROUND_UP(_ud_size, 4)] __net_buf_align; \
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} _name[_count] = { \
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[0 ... (_count - 1)] = { .buf = { \
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.user_data_size = ROUND_UP(_ud_size, 4), \
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.free = _fifo, \
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.destroy = _destroy, \
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.size = ROUND_UP(_size, 4) } }, \
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}
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/** @brief Initialize an available buffers FIFO based on a pool.
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*
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* Initializes a buffer pool created using NET_BUF_POOL(). After
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* calling this API the buffers can ge accessed through the FIFO that
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* was given to NET_BUF_POOL(), i.e. after this call there should be no
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* need to access the buffer pool (struct array) directly anymore.
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*
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* @param pool Buffer pool to initialize.
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*/
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#define net_buf_pool_init(pool) \
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do { \
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int i; \
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\
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nano_fifo_init(pool[0].buf.free); \
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\
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for (i = 0; i < ARRAY_SIZE(pool); i++) { \
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nano_fifo_put(pool[i].buf.free, &pool[i]); \
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} \
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} while (0)
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/** @brief Get a new buffer from the pool.
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*
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* Get buffer from the available buffers pool with specified type and
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* reserved headroom.
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*
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* @param fifo Which FIFO to take the buffer from.
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* @param reserve_head How much headroom to reserve.
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*
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* @return New buffer or NULL if out of buffers.
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*
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* @warning If there are no available buffers and the function is
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* called from a task or fiber the call will block until a buffer
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* becomes available in the pool.
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*/
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struct net_buf *net_buf_get(struct nano_fifo *fifo, size_t reserve_head);
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/** @brief Decrements the reference count of a buffer.
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*
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* Decrements the reference count of a buffer and puts it back into the
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* pool if the count reaches zero.
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*
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* @param buf Buffer.
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*/
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void net_buf_unref(struct net_buf *buf);
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/** Increment the reference count of a buffer.
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*
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* Increment the reference count of a buffer.
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*
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* @param buf Buffer.
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*/
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struct net_buf *net_buf_ref(struct net_buf *buf);
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/** @brief Duplicate buffer
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*
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* Duplicate given buffer including any data and headers currently stored.
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*
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* @param buf Buffer.
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*
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* @return Duplicated buffer or NULL if out of buffers.
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*/
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struct net_buf *net_buf_clone(struct net_buf *buf);
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/** Get a pointer to the user data of a buffer.
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*
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* @param buf The buffer in question.
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*
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* @return Pointer to the user data of the buffer.
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*/
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#define net_buf_user_data(buf) \
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((void *)(ROUND_UP(((buf)->__buf + (buf)->size), sizeof(int))))
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/** @brief Prepare data to be added at the end of the buffer
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*
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* Increments the data length of a buffer to account for more data
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* at the end.
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*
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* @param buf Buffer to update.
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* @param len Number of bytes to increment the length with.
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*
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* @return The original tail of the buffer.
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*/
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void *net_buf_add(struct net_buf *buf, size_t len);
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/** @brief Add 16-bit value at the end of the buffer
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*
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* Adds 16-bit value in little endian format at the end of buffer.
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* Increments the data length of a buffer to account for more data
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* at the end.
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*
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* @param buf Buffer to update.
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* @param value 16-bit value to be added.
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*
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* @return void
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*/
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void net_buf_add_le16(struct net_buf *buf, uint16_t value);
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/** @brief Push data to the beginning of the buffer.
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*
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* Modifies the data pointer and buffer length to account for more data
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* in the beginning of the buffer.
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*
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* @param buf Buffer to update.
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* @param len Number of bytes to add to the beginning.
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*
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* @return The new beginning of the buffer data.
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*/
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void *net_buf_push(struct net_buf *buf, size_t len);
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/** @brief Remove data from the beginning of the buffer.
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*
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* Removes data from the beginnig of the buffer by modifying the data
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* pointer and buffer length.
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*
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* @param buf Buffer to update.
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* @param len Number of bytes to remove.
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*
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* @return New beginning of the buffer data.
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*/
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void *net_buf_pull(struct net_buf *buf, size_t len);
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/** @brief Remove and convert 16 bits from the beginning of the buffer.
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*
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* Same idea as with bt_buf_pull(), but a helper for operating on
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* 16-bit little endian data.
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*
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* @param buf Buffer.
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*
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* @return 16-bit value converted from little endian to host endian.
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*/
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uint16_t net_buf_pull_le16(struct net_buf *buf);
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/** @brief Check buffer tailroom.
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*
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* Check how much free space there is at the end of the buffer.
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*
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* @return Number of bytes available at the end of the buffer.
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*/
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size_t net_buf_tailroom(struct net_buf *buf);
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/** @brief Check buffer headroom.
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*
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* Check how much free space there is in the beginning of the buffer.
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*
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* @return Number of bytes available in the beginning of the buffer.
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*/
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size_t net_buf_headroom(struct net_buf *buf);
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/** @def net_buf_tail
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* @brief Get the tail pointer for a buffer.
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*
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* Get a pointer to the end of the data in a buffer.
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*
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* @param buf Buffer.
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*
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* @return Tail pointer for the buffer.
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*/
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#define net_buf_tail(buf) ((buf)->data + (buf)->len)
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#endif /* __NET_BUF_H */
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