| #pragma once |
| |
| /* (C) 2008 by Harald Welte <laforge@gnumonks.org> |
| * All Rights Reserved |
| * |
| * 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 2 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, write to the Free Software Foundation, Inc., |
| * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| */ |
| |
| #include <stdint.h> |
| #include <osmocom/core/linuxlist.h> |
| #include <osmocom/core/utils.h> |
| #include <osmocom/core/bits.h> |
| |
| /*! \defgroup msgb Message buffers |
| * @{ |
| */ |
| |
| /*! \file msgb.h |
| * \brief Osmocom message buffers |
| * The Osmocom message buffers are modelled after the 'struct skb' |
| * inside the Linux kernel network stack. As they exist in userspace, |
| * they are much simplified. However, terminology such as headroom, |
| * tailroom, push/pull/put etc. remains the same. |
| */ |
| |
| #define MSGB_DEBUG |
| |
| /*! \brief Osmocom message buffer */ |
| struct msgb { |
| struct llist_head list; /*!< \brief linked list header */ |
| |
| |
| /* Part of which TRX logical channel we were received / transmitted */ |
| /* FIXME: move them into the control buffer */ |
| union { |
| void *dst; /*!< \brief reference of origin/destination */ |
| struct gsm_bts_trx *trx; |
| }; |
| struct gsm_lchan *lchan; /*!< \brief logical channel */ |
| |
| unsigned char *l1h; /*!< \brief pointer to Layer1 header (if any) */ |
| unsigned char *l2h; /*!< \brief pointer to A-bis layer 2 header: OML, RSL(RLL), NS */ |
| unsigned char *l3h; /*!< \brief pointer to Layer 3 header. For OML: FOM; RSL: 04.08; GPRS: BSSGP */ |
| unsigned char *l4h; /*!< \brief pointer to layer 4 header */ |
| |
| unsigned long cb[5]; /*!< \brief control buffer */ |
| |
| uint16_t data_len; /*!< \brief length of underlying data array */ |
| uint16_t len; /*!< \brief length of bytes used in msgb */ |
| |
| unsigned char *head; /*!< \brief start of underlying memory buffer */ |
| unsigned char *tail; /*!< \brief end of message in buffer */ |
| unsigned char *data; /*!< \brief start of message in buffer */ |
| unsigned char _data[0]; /*!< \brief optional immediate data array */ |
| }; |
| |
| extern struct msgb *msgb_alloc(uint16_t size, const char *name); |
| extern void msgb_free(struct msgb *m); |
| extern void msgb_enqueue(struct llist_head *queue, struct msgb *msg); |
| extern struct msgb *msgb_dequeue(struct llist_head *queue); |
| extern void msgb_reset(struct msgb *m); |
| uint16_t msgb_length(const struct msgb *msg); |
| extern const char *msgb_hexdump(const struct msgb *msg); |
| extern int msgb_resize_area(struct msgb *msg, uint8_t *area, |
| int old_size, int new_size); |
| extern struct msgb *msgb_copy(const struct msgb *msg, const char *name); |
| static int msgb_test_invariant(const struct msgb *msg) __attribute__((pure)); |
| |
| #ifdef MSGB_DEBUG |
| #include <osmocom/core/panic.h> |
| #define MSGB_ABORT(msg, fmt, args ...) do { \ |
| osmo_panic("msgb(%p): " fmt, msg, ## args); \ |
| } while(0) |
| #else |
| #define MSGB_ABORT(msg, fmt, args ...) |
| #endif |
| |
| /*! \brief obtain L1 header of msgb */ |
| #define msgb_l1(m) ((void *)(m->l1h)) |
| /*! \brief obtain L2 header of msgb */ |
| #define msgb_l2(m) ((void *)(m->l2h)) |
| /*! \brief obtain L3 header of msgb */ |
| #define msgb_l3(m) ((void *)(m->l3h)) |
| /*! \brief obtain SMS header of msgb */ |
| #define msgb_sms(m) ((void *)(m->l4h)) |
| |
| /*! \brief determine length of L1 message |
| * \param[in] msgb message buffer |
| * \returns size of L1 message in bytes |
| * |
| * This function computes the number of bytes between the tail of the |
| * message and the layer 1 header. |
| */ |
| static inline unsigned int msgb_l1len(const struct msgb *msgb) |
| { |
| return msgb->tail - (uint8_t *)msgb_l1(msgb); |
| } |
| |
| /*! \brief determine length of L2 message |
| * \param[in] msgb message buffer |
| * \returns size of L2 message in bytes |
| * |
| * This function computes the number of bytes between the tail of the |
| * message and the layer 2 header. |
| */ |
| static inline unsigned int msgb_l2len(const struct msgb *msgb) |
| { |
| return msgb->tail - (uint8_t *)msgb_l2(msgb); |
| } |
| |
| /*! \brief determine length of L3 message |
| * \param[in] msgb message buffer |
| * \returns size of L3 message in bytes |
| * |
| * This function computes the number of bytes between the tail of the |
| * message and the layer 3 header. |
| */ |
| static inline unsigned int msgb_l3len(const struct msgb *msgb) |
| { |
| return msgb->tail - (uint8_t *)msgb_l3(msgb); |
| } |
| |
| /*! \brief determine the length of the header |
| * \param[in] msgb message buffer |
| * \returns number of bytes between start of buffer and start of msg |
| * |
| * This function computes the length difference between the underlying |
| * data buffer and the used section of the \a msgb. |
| */ |
| static inline unsigned int msgb_headlen(const struct msgb *msgb) |
| { |
| return msgb->len - msgb->data_len; |
| } |
| |
| /*! \brief determine how much tail room is left in msgb |
| * \param[in] msgb message buffer |
| * \returns number of bytes remaining at end of msgb |
| * |
| * This function computes the amount of octets left in the underlying |
| * data buffer after the end of the message. |
| */ |
| static inline int msgb_tailroom(const struct msgb *msgb) |
| { |
| return (msgb->head + msgb->data_len) - msgb->tail; |
| } |
| |
| /*! \brief determine the amount of headroom in msgb |
| * \param[in] msgb message buffer |
| * \returns number of bytes left ahead of message start in msgb |
| * |
| * This function computes the amount of bytes left in the underlying |
| * data buffer before the start of the actual message. |
| */ |
| static inline int msgb_headroom(const struct msgb *msgb) |
| { |
| return (msgb->data - msgb->head); |
| } |
| |
| /*! \brief append data to end of message buffer |
| * \param[in] msgb message buffer |
| * \param[in] len number of bytes to append to message |
| * \returns pointer to start of newly-appended data |
| * |
| * This function will move the \a tail pointer of the message buffer \a |
| * len bytes further, thus enlarging the message by \a len bytes. |
| * |
| * The return value is a pointer to start of the newly added section at |
| * the end of the message and can be used for actually filling/copying |
| * data into it. |
| */ |
| static inline unsigned char *msgb_put(struct msgb *msgb, unsigned int len) |
| { |
| unsigned char *tmp = msgb->tail; |
| if (msgb_tailroom(msgb) < (int) len) |
| MSGB_ABORT(msgb, "Not enough tailroom msgb_push (%u < %u)\n", |
| msgb_tailroom(msgb), len); |
| msgb->tail += len; |
| msgb->len += len; |
| return tmp; |
| } |
| |
| /*! \brief append a uint8 value to the end of the message |
| * \param[in] msgb message buffer |
| * \param[in] word unsigned 8bit byte to be appended |
| */ |
| static inline void msgb_put_u8(struct msgb *msgb, uint8_t word) |
| { |
| uint8_t *space = msgb_put(msgb, 1); |
| space[0] = word & 0xFF; |
| } |
| |
| /*! \brief append a uint16 value to the end of the message |
| * \param[in] msgb message buffer |
| * \param[in] word unsigned 16bit byte to be appended |
| */ |
| static inline void msgb_put_u16(struct msgb *msgb, uint16_t word) |
| { |
| uint8_t *space = msgb_put(msgb, 2); |
| osmo_store16be(word, space); |
| } |
| |
| /*! \brief append a uint32 value to the end of the message |
| * \param[in] msgb message buffer |
| * \param[in] word unsigned 32bit byte to be appended |
| */ |
| static inline void msgb_put_u32(struct msgb *msgb, uint32_t word) |
| { |
| uint8_t *space = msgb_put(msgb, 4); |
| osmo_store32be(word, space); |
| } |
| |
| /*! \brief remove data from end of message |
| * \param[in] msgb message buffer |
| * \param[in] len number of bytes to remove from end |
| */ |
| static inline unsigned char *msgb_get(struct msgb *msgb, unsigned int len) |
| { |
| unsigned char *tmp = msgb->tail - len; |
| if (msgb_length(msgb) < len) |
| MSGB_ABORT(msgb, "msgb too small to get %u (len %u)\n", |
| len, msgb_length(msgb)); |
| msgb->tail -= len; |
| msgb->len -= len; |
| return tmp; |
| } |
| |
| /*! \brief remove uint8 from end of message |
| * \param[in] msgb message buffer |
| * \returns 8bit value taken from end of msgb |
| */ |
| static inline uint8_t msgb_get_u8(struct msgb *msgb) |
| { |
| uint8_t *space = msgb_get(msgb, 1); |
| return space[0]; |
| } |
| |
| /*! \brief remove uint16 from end of message |
| * \param[in] msgb message buffer |
| * \returns 16bit value taken from end of msgb |
| */ |
| static inline uint16_t msgb_get_u16(struct msgb *msgb) |
| { |
| uint8_t *space = msgb_get(msgb, 2); |
| return osmo_load16be(space); |
| } |
| |
| /*! \brief remove uint32 from end of message |
| * \param[in] msgb message buffer |
| * \returns 32bit value taken from end of msgb |
| */ |
| static inline uint32_t msgb_get_u32(struct msgb *msgb) |
| { |
| uint8_t *space = msgb_get(msgb, 4); |
| return osmo_load32be(space); |
| } |
| |
| /*! \brief prepend (push) some data to start of message |
| * \param[in] msgb message buffer |
| * \param[in] len number of bytes to pre-pend |
| * \returns pointer to newly added portion at start of \a msgb |
| * |
| * This function moves the \a data pointer of the \ref msgb further |
| * to the front (by \a len bytes), thereby enlarging the message by \a |
| * len bytes. |
| * |
| * The return value is a pointer to the newly added section in the |
| * beginning of the message. It can be used to fill/copy data into it. |
| */ |
| static inline unsigned char *msgb_push(struct msgb *msgb, unsigned int len) |
| { |
| if (msgb_headroom(msgb) < (int) len) |
| MSGB_ABORT(msgb, "Not enough headroom msgb_push (%u < %u)\n", |
| msgb_headroom(msgb), len); |
| msgb->data -= len; |
| msgb->len += len; |
| return msgb->data; |
| } |
| |
| /*! \brief remove (pull) a header from the front of the message buffer |
| * \param[in] msgb message buffer |
| * \param[in] len number of octets to be pulled |
| * \returns pointer to new start of msgb |
| * |
| * This function moves the \a data pointer of the \ref msgb further back |
| * in the message, thereby shrinking the size of the message by \a len |
| * bytes. |
| */ |
| static inline unsigned char *msgb_pull(struct msgb *msgb, unsigned int len) |
| { |
| msgb->len -= len; |
| return msgb->data += len; |
| } |
| |
| /*! \brief remove (pull) all headers in front of l3h from the message buffer. |
| * \param[in] msgb message buffer with a valid l3h |
| * \returns pointer to new start of msgb (l3h) |
| * |
| * This function moves the \a data pointer of the \ref msgb further back |
| * in the message, thereby shrinking the size of the message. |
| * l1h and l2h will be cleared. |
| */ |
| static inline unsigned char *msgb_pull_to_l3(struct msgb *msg) |
| { |
| unsigned char *ret = msgb_pull(msg, msg->l3h - msg->data); |
| msg->l1h = msg->l2h = NULL; |
| return ret; |
| } |
| |
| /*! \brief remove uint8 from front of message |
| * \param[in] msgb message buffer |
| * \returns 8bit value taken from end of msgb |
| */ |
| static inline uint8_t msgb_pull_u8(struct msgb *msgb) |
| { |
| uint8_t *space = msgb_pull(msgb, 1) - 1; |
| return space[0]; |
| } |
| |
| /*! \brief remove uint16 from front of message |
| * \param[in] msgb message buffer |
| * \returns 16bit value taken from end of msgb |
| */ |
| static inline uint16_t msgb_pull_u16(struct msgb *msgb) |
| { |
| uint8_t *space = msgb_pull(msgb, 2) - 2; |
| return osmo_load16be(space); |
| } |
| |
| /*! \brief remove uint32 from front of message |
| * \param[in] msgb message buffer |
| * \returns 32bit value taken from end of msgb |
| */ |
| static inline uint32_t msgb_pull_u32(struct msgb *msgb) |
| { |
| uint8_t *space = msgb_pull(msgb, 4) - 4; |
| return osmo_load32be(space); |
| } |
| |
| /*! \brief Increase headroom of empty msgb, reducing the tailroom |
| * \param[in] msg message buffer |
| * \param[in] len amount of extra octets to be reserved as headroom |
| * |
| * This function reserves some memory at the beginning of the underlying |
| * data buffer. The idea is to reserve space in case further headers |
| * have to be pushed to the \ref msgb during further processing. |
| * |
| * Calling this function leads to undefined reusults if it is called on |
| * a non-empty \ref msgb. |
| */ |
| static inline void msgb_reserve(struct msgb *msg, int len) |
| { |
| msg->data += len; |
| msg->tail += len; |
| } |
| |
| /*! \brief Trim the msgb to a given absolute length |
| * \param[in] msg message buffer |
| * \param[in] len new total length of buffer |
| * \returns 0 in case of success, negative in case of error |
| */ |
| static inline int msgb_trim(struct msgb *msg, int len) |
| { |
| if (len < 0) |
| MSGB_ABORT(msg, "Negative length is not allowed\n"); |
| if (len > msg->data_len) |
| return -1; |
| |
| msg->len = len; |
| msg->tail = msg->data + len; |
| |
| return 0; |
| } |
| |
| /*! \brief Trim the msgb to a given layer3 length |
| * \param[in] msg message buffer |
| * \param[in] l3len new layer3 length |
| * \returns 0 in case of success, negative in case of error |
| */ |
| static inline int msgb_l3trim(struct msgb *msg, int l3len) |
| { |
| return msgb_trim(msg, (msg->l3h - msg->data) + l3len); |
| } |
| |
| /*! \brief Allocate message buffer with specified headroom |
| * \param[in] size size in bytes, including headroom |
| * \param[in] headroom headroom in bytes |
| * \param[in] name human-readable name |
| * \returns allocated message buffer with specified headroom |
| * |
| * This function is a convenience wrapper around \ref msgb_alloc |
| * followed by \ref msgb_reserve in order to create a new \ref msgb with |
| * user-specified amount of headroom. |
| */ |
| static inline struct msgb *msgb_alloc_headroom(int size, int headroom, |
| const char *name) |
| { |
| osmo_static_assert(size > headroom, headroom_bigger); |
| |
| struct msgb *msg = msgb_alloc(size, name); |
| if (msg) |
| msgb_reserve(msg, headroom); |
| return msg; |
| } |
| |
| /*! \brief Check a message buffer for consistency |
| * \param[in] msg message buffer |
| * \returns 0 (false) if inconsistent, != 0 (true) otherwise |
| */ |
| static inline int msgb_test_invariant(const struct msgb *msg) |
| { |
| const unsigned char *lbound; |
| if (!msg || !msg->data || !msg->tail || |
| (msg->data + msg->len != msg->tail) || |
| (msg->data < msg->head) || |
| (msg->tail > msg->head + msg->data_len)) |
| return 0; |
| |
| lbound = msg->head; |
| |
| if (msg->l1h) { |
| if (msg->l1h < lbound) |
| return 0; |
| lbound = msg->l1h; |
| } |
| if (msg->l2h) { |
| if (msg->l2h < lbound) |
| return 0; |
| lbound = msg->l2h; |
| } |
| if (msg->l3h) { |
| if (msg->l3h < lbound) |
| return 0; |
| lbound = msg->l3h; |
| } |
| if (msg->l4h) { |
| if (msg->l4h < lbound) |
| return 0; |
| lbound = msg->l4h; |
| } |
| |
| return lbound <= msg->head + msg->data_len; |
| } |
| |
| /* non inline functions to ease binding */ |
| |
| uint8_t *msgb_data(const struct msgb *msg); |
| void msgb_set_talloc_ctx(void *ctx); |
| |
| /*! @} */ |