345 lines
11 KiB
C
345 lines
11 KiB
C
#ifndef _MSGB_H
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#define _MSGB_H
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/* (C) 2008 by Harald Welte <laforge@gnumonks.org>
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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*/
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#include <stdint.h>
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#include <osmocom/core/linuxlist.h>
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#include <osmocom/core/utils.h>
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/*! \defgroup msgb Message buffers
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* @{
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*/
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/*! \file msgb.h
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* \brief Osmocom message buffers
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* The Osmocom message buffers are modelled after the 'struct skb'
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* inside the Linux kernel network stack. As they exist in userspace,
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* they are much simplified. However, terminology such as headroom,
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* tailroom, push/pull/put etc. remains the same.
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*/
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#define MSGB_DEBUG
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/*! \brief Osmocom message buffer */
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struct msgb {
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struct llist_head list; /*!< \brief linked list header */
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/* Part of which TRX logical channel we were received / transmitted */
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/* FIXME: move them into the control buffer */
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union {
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void *dst; /*!< \brief reference of origin/destination */
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struct gsm_bts_trx *trx;
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};
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struct gsm_lchan *lchan; /*!< \brief logical channel */
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unsigned char *l1h; /*!< \brief pointer to Layer1 header (if any) */
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unsigned char *l2h; /*!< \brief pointer to A-bis layer 2 header: OML, RSL(RLL), NS */
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unsigned char *l3h; /*!< \brief pointer to Layer 3 header. For OML: FOM; RSL: 04.08; GPRS: BSSGP */
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unsigned char *l4h; /*!< \brief pointer to layer 4 header */
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unsigned long cb[5]; /*!< \brief control buffer */
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uint16_t data_len; /*!< \brief length of underlying data array */
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uint16_t len; /*!< \brief length of bytes used in msgb */
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unsigned char *head; /*!< \brief start of underlying memory buffer */
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unsigned char *tail; /*!< \brief end of message in buffer */
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unsigned char *data; /*!< \brief start of message in buffer */
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unsigned char _data[0]; /*!< \brief optional immediate data array */
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};
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extern struct msgb *msgb_alloc(uint16_t size, const char *name);
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extern void msgb_free(struct msgb *m);
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extern void msgb_enqueue(struct llist_head *queue, struct msgb *msg);
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extern struct msgb *msgb_dequeue(struct llist_head *queue);
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extern void msgb_reset(struct msgb *m);
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#ifdef MSGB_DEBUG
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#include <osmocom/core/panic.h>
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#define MSGB_ABORT(msg, fmt, args ...) do { \
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osmo_panic("msgb(%p): " fmt, msg, ## args); \
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} while(0)
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#else
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#define MSGB_ABORT(msg, fmt, args ...)
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#endif
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/*! \brief obtain L1 header of msgb */
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#define msgb_l1(m) ((void *)(m->l1h))
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/*! \brief obtain L2 header of msgb */
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#define msgb_l2(m) ((void *)(m->l2h))
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/*! \brief obtain L3 header of msgb */
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#define msgb_l3(m) ((void *)(m->l3h))
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/*! \brief obtain SMS header of msgb */
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#define msgb_sms(m) ((void *)(m->l4h))
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/*! \brief determine length of L1 message
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* \param[in] msgb message buffer
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* \returns size of L1 message in bytes
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*
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* This function computes the number of bytes between the tail of the
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* message and the layer 1 header.
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*/
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static inline unsigned int msgb_l1len(const struct msgb *msgb)
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{
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return msgb->tail - (uint8_t *)msgb_l1(msgb);
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}
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/*! \brief determine length of L2 message
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* \param[in] msgb message buffer
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* \returns size of L2 message in bytes
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*
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* This function computes the number of bytes between the tail of the
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* message and the layer 2 header.
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*/
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static inline unsigned int msgb_l2len(const struct msgb *msgb)
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{
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return msgb->tail - (uint8_t *)msgb_l2(msgb);
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}
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/*! \brief determine length of L3 message
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* \param[in] msgb message buffer
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* \returns size of L3 message in bytes
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*
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* This function computes the number of bytes between the tail of the
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* message and the layer 3 header.
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*/
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static inline unsigned int msgb_l3len(const struct msgb *msgb)
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{
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return msgb->tail - (uint8_t *)msgb_l3(msgb);
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}
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/*! \brief determine the length of the header
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* \param[in] msgb message buffer
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* \returns number of bytes between start of buffer and start of msg
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*
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* This function computes the length difference between the underlying
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* data buffer and the used section of the \a msgb.
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*/
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static inline unsigned int msgb_headlen(const struct msgb *msgb)
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{
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return msgb->len - msgb->data_len;
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}
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/*! \brief determine how much tail room is left in msgb
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* \param[in] msgb message buffer
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* \returns number of bytes remaining at end of msgb
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*
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* This function computes the amount of octets left in the underlying
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* data buffer after the end of the message.
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*/
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static inline int msgb_tailroom(const struct msgb *msgb)
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{
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return (msgb->head + msgb->data_len) - msgb->tail;
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}
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/*! \brief determine the amount of headroom in msgb
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* \param[in] msgb message buffer
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* \returns number of bytes left ahead of message start in msgb
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*
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* This function computes the amount of bytes left in the underlying
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* data buffer before the start of the actual message.
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*/
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static inline int msgb_headroom(const struct msgb *msgb)
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{
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return (msgb->data - msgb->head);
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}
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/*! \brief append data to end of message buffer
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* \param[in] msgb message buffer
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* \param[in] len number of bytes to append to message
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* \returns pointer to start of newly-appended data
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*
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* This function will move the \a tail pointer of the message buffer \a
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* len bytes further, thus enlarging the message by \a len bytes.
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*
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* The return value is a pointer to start of the newly added section at
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* the end of the message and can be used for actually filling/copying
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* data into it.
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*/
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static inline unsigned char *msgb_put(struct msgb *msgb, unsigned int len)
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{
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unsigned char *tmp = msgb->tail;
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if (msgb_tailroom(msgb) < (int) len)
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MSGB_ABORT(msgb, "Not enough tailroom msgb_push (%u < %u)\n",
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msgb_tailroom(msgb), len);
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msgb->tail += len;
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msgb->len += len;
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return tmp;
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}
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/*! \brief append a uint8 value to the end of the message
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* \param[in] msgb message buffer
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* \param[in] word unsigned 8bit byte to be appended
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*/
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static inline void msgb_put_u8(struct msgb *msgb, uint8_t word)
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{
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uint8_t *space = msgb_put(msgb, 1);
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space[0] = word & 0xFF;
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}
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/*! \brief append a uint16 value to the end of the message
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* \param[in] msgb message buffer
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* \param[in] word unsigned 16bit byte to be appended
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*/
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static inline void msgb_put_u16(struct msgb *msgb, uint16_t word)
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{
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uint8_t *space = msgb_put(msgb, 2);
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space[0] = word >> 8 & 0xFF;
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space[1] = word & 0xFF;
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}
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/*! \brief append a uint32 value to the end of the message
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* \param[in] msgb message buffer
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* \param[in] word unsigned 32bit byte to be appended
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*/
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static inline void msgb_put_u32(struct msgb *msgb, uint32_t word)
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{
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uint8_t *space = msgb_put(msgb, 4);
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space[0] = word >> 24 & 0xFF;
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space[1] = word >> 16 & 0xFF;
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space[2] = word >> 8 & 0xFF;
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space[3] = word & 0xFF;
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}
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/*! \brief remove data from end of message
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* \param[in] msgb message buffer
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* \param[in] len number of bytes to remove from end
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*/
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static inline unsigned char *msgb_get(struct msgb *msgb, unsigned int len)
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{
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unsigned char *tmp = msgb->data;
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msgb->data += len;
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msgb->len -= len;
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return tmp;
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}
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/*! \brief remove uint8 from end of message
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* \param[in] msgb message buffer
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* \returns 8bit value taken from end of msgb
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*/
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static inline uint8_t msgb_get_u8(struct msgb *msgb)
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{
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uint8_t *space = msgb_get(msgb, 1);
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return space[0];
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}
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/*! \brief remove uint16 from end of message
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* \param[in] msgb message buffer
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* \returns 16bit value taken from end of msgb
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*/
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static inline uint16_t msgb_get_u16(struct msgb *msgb)
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{
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uint8_t *space = msgb_get(msgb, 2);
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return space[0] << 8 | space[1];
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}
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/*! \brief remove uint32 from end of message
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* \param[in] msgb message buffer
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* \returns 32bit value taken from end of msgb
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*/
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static inline uint32_t msgb_get_u32(struct msgb *msgb)
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{
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uint8_t *space = msgb_get(msgb, 4);
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return space[0] << 24 | space[1] << 16 | space[2] << 8 | space[3];
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}
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/*! \brief prepend (push) some data to start of message
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* \param[in] msgb message buffer
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* \param[in] len number of bytes to pre-pend
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* \returns pointer to newly added portion at start of \a msgb
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*
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* This function moves the \a data pointer of the \ref msgb further
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* to the front (by \a len bytes), thereby enlarging the message by \a
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* len bytes.
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*
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* The return value is a pointer to the newly added section in the
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* beginning of the message. It can be used to fill/copy data into it.
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*/
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static inline unsigned char *msgb_push(struct msgb *msgb, unsigned int len)
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{
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if (msgb_headroom(msgb) < (int) len)
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MSGB_ABORT(msgb, "Not enough headroom msgb_push (%u < %u)\n",
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msgb_headroom(msgb), len);
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msgb->data -= len;
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msgb->len += len;
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return msgb->data;
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}
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/*! \brief remove (pull) a header from the front of the message buffer
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* \param[in] msgb message buffer
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* \param[in] len number of octets to be pulled
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* \returns pointer to new start of msgb
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*
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* This function moves the \a data pointer of the \ref msgb further back
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* in the message, thereby shrinking the size of the message by \a len
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* bytes.
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*/
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static inline unsigned char *msgb_pull(struct msgb *msgb, unsigned int len)
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{
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msgb->len -= len;
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return msgb->data += len;
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}
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/*! \brief Increase headroom of empty msgb, reducing the tailroom
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* \param[in] msg message buffer
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* \param[in] len amount of extra octets to be reserved as headroom
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*
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* This function reserves some memory at the beginning of the underlying
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* data buffer. The idea is to reserve space in case further headers
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* have to be pushed to the \ref msgb during further processing.
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*
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* Calling this function leads to undefined reusults if it is called on
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* a non-empty \ref msgb.
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*/
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static inline void msgb_reserve(struct msgb *msg, int len)
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{
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msg->data += len;
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msg->tail += len;
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}
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/*! \brief Allocate message buffer with specified headroom
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* \param[in] size size in bytes, including headroom
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* \param[in] headroom headroom in bytes
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* \param[in] name human-readable name
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* \returns allocated message buffer with specified headroom
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*
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* This function is a convenience wrapper around \ref msgb_alloc
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* followed by \ref msgb_reserve in order to create a new \ref msgb with
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* user-specified amount of headroom.
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*/
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static inline struct msgb *msgb_alloc_headroom(int size, int headroom,
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const char *name)
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{
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osmo_static_assert(size > headroom, headroom_bigger);
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struct msgb *msg = msgb_alloc(size, name);
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if (msg)
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msgb_reserve(msg, headroom);
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return msg;
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}
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/* non inline functions to ease binding */
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uint8_t *msgb_data(const struct msgb *msg);
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uint16_t msgb_length(const struct msgb *msg);
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void msgb_set_talloc_ctx(void *ctx);
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/*! }@ */
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#endif /* _MSGB_H */
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