Data Structures
struct	msgb
	Osmocom message buffer. More...
Files
file	msgb.h
	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.
file	msgb.c
Functions
struct msgb *	msgb_alloc (uint16_t size, const char *name)
	Allocate a new message buffer.
void	msgb_free (struct msgb *m)
	Release given message buffer.
void	msgb_enqueue (struct llist_head queue, struct msgb msg)
	Enqueue message buffer to tail of a queue.
struct msgb *	msgb_dequeue (struct llist_head *queue)
	Dequeue message buffer from head of queue.
void	msgb_reset (struct msgb *msg)
	Re-set all message buffer pointers.
static unsigned int	msgb_l1len (const struct msgb *msgb)
	determine length of L1 message
static unsigned int	msgb_l2len (const struct msgb *msgb)
	determine length of L2 message
static unsigned int	msgb_l3len (const struct msgb *msgb)
	determine length of L3 message
static unsigned int	msgb_headlen (const struct msgb *msgb)
	determine the length of the header
static int	msgb_tailroom (const struct msgb *msgb)
	determine how much tail room is left in msgb
static int	msgb_headroom (const struct msgb *msgb)
	determine the amount of headroom in msgb
static unsigned char *	msgb_put (struct msgb *msgb, unsigned int len)
	append data to end of message buffer
static void	msgb_put_u8 (struct msgb *msgb, uint8_t word)
	append a uint8 value to the end of the message
static void	msgb_put_u16 (struct msgb *msgb, uint16_t word)
	append a uint16 value to the end of the message
static void	msgb_put_u32 (struct msgb *msgb, uint32_t word)
	append a uint32 value to the end of the message
static unsigned char *	msgb_get (struct msgb *msgb, unsigned int len)
	remove data from end of message
static uint8_t	msgb_get_u8 (struct msgb *msgb)
	remove uint8 from end of message
static uint16_t	msgb_get_u16 (struct msgb *msgb)
	remove uint16 from end of message
static uint32_t	msgb_get_u32 (struct msgb *msgb)
	remove uint32 from end of message
static unsigned char *	msgb_push (struct msgb *msgb, unsigned int len)
	prepend (push) some data to start of message
static unsigned char *	msgb_pull (struct msgb *msgb, unsigned int len)
	remove (pull) a header from the front of the message buffer
static void	msgb_reserve (struct msgb *msg, int len)
	Increase headroom of empty msgb, reducing the tailroom.
static struct msgb *	msgb_alloc_headroom (int size, int headroom, const char *name)
	Allocate message buffer with specified headroom.
uint8_t *	msgb_data (const struct msgb *msg)
	get pointer to data section of message buffer
uint16_t	msgb_length (const struct msgb *msg)
	get length of message buffer
void	msgb_set_talloc_ctx (void *ctx)
	Set the talloc context for msgb_alloc.
Variables
struct gsm_bts_trx * msgb::@5::trx
union {
void * dst
	reference of origin/destination
struct gsm_bts_trx * trx
};
struct gsm_lchan *	msgb::lchan
	logical channel
unsigned char *	msgb::l1h
	pointer to Layer1 header (if any)
unsigned char *	msgb::l2h
	pointer to A-bis layer 2 header: OML, RSL(RLL), NS
unsigned char *	msgb::l3h
	pointer to Layer 3 header. For OML: FOM; RSL: 04.08; GPRS: BSSGP
unsigned char *	msgb::l4h
	pointer to layer 4 header
unsigned long	msgb::cb [5]
	control buffer
uint16_t	msgb::data_len
	length of underlying data array
uint16_t	msgb::len
	length of bytes used in msgb
unsigned char *	msgb::head
	start of underlying memory buffer
unsigned char *	msgb::tail
	end of message in buffer
unsigned char *	msgb::data
	start of message in buffer
unsigned char	msgb::_data [0]
	optional immediate data array
void *	tall_msgb_ctx

Function Documentation

struct msgb * msgb_alloc	(	uint16_t	size,
		const char *	name
	)		`[read]`

Allocate a new message buffer.

Parameters:

[in]	size	Length in octets, including headroom
[in]	name	Human-readable name to be associated with msgb

This function allocates a 'struct msgb' as well as the underlying memory buffer for the actual message data (size specified by size) using the talloc memory context previously set by msgb_set_talloc_ctx

References _data, data, data_len, head, len, and tail.

Referenced by gsmtap_makemsg(), and msgb_alloc_headroom().

static struct msgb* msgb_alloc_headroom	(	int	size,
		int	headroom,
		const char *	name
	)		`[static, read]`

Allocate message buffer with specified headroom.

Parameters:

[in]	size	size in bytes, including headroom
[in]	headroom	headroom in bytes
[in]	name	human-readable name

Returns:: allocated message buffer with specified headroom

This function is a convenience wrapper around msgb_alloc followed by msgb_reserve in order to create a new Message buffers with user-specified amount of headroom.

References msgb_alloc(), and msgb_reserve().

uint8_t * msgb_data ( const struct msgb * msg )

get pointer to data section of message buffer

Parameters:

[in] msg message buffer

Returns:: pointer to data section of message buffer

References data.

struct msgb * msgb_dequeue ( struct llist_head * queue ) [read]

Dequeue message buffer from head of queue.

Parameters:

[in] queue linked list header of queue

Returns:: message buffer (if any) or NULL if queue empty

The function will remove the first message buffer from the queue implemented by 'ref llist_head queue.

Referenced by osmo_wqueue_bfd_cb(), and osmo_wqueue_clear().

void msgb_enqueue	(	struct llist_head *	queue,
		struct msgb *	msg
	)

Enqueue message buffer to tail of a queue.

Parameters:

[in]	queue	linked list header of queue
[in]	msgb	message buffer to be added to the queue

The function will append the specified message buffer msg to the queue implemented by llist_head queue

References list.

Referenced by osmo_wqueue_enqueue().

void msgb_free ( struct msgb * m )

Release given message buffer.

Parameters:

[in] m Message buffer to be free'd

Referenced by gsmtap_sendmsg(), osmo_wqueue_bfd_cb(), and osmo_wqueue_clear().

static unsigned char* msgb_get	(	struct msgb *	msgb,
		unsigned int	len
	)		`[inline, static]`

remove data from end of message

Parameters:

[in]	msgb	message buffer
[in]	len	number of bytes to remove from end

References data, and len.

Referenced by msgb_get_u16(), msgb_get_u32(), and msgb_get_u8().

static uint16_t msgb_get_u16 ( struct msgb * msgb ) [inline, static]

remove uint16 from end of message

Parameters:

[in] msgb message buffer

Returns:: 16bit value taken from end of msgb

References msgb_get().

static uint32_t msgb_get_u32 ( struct msgb * msgb ) [inline, static]

remove uint32 from end of message

Parameters:

[in] msgb message buffer

Returns:: 32bit value taken from end of msgb

References msgb_get().

static uint8_t msgb_get_u8 ( struct msgb * msgb ) [inline, static]

remove uint8 from end of message

Parameters:

[in] msgb message buffer

Returns:: 8bit value taken from end of msgb

References msgb_get().

static unsigned int msgb_headlen ( const struct msgb * msgb ) [inline, static]

determine the length of the header

Parameters:

[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 msgb.

References data_len, and len.

static int msgb_headroom ( const struct msgb * msgb ) [inline, static]

determine the amount of headroom in msgb

Parameters:

[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.

References data, and head.

Referenced by msgb_push().

static unsigned int msgb_l1len ( const struct msgb * msgb ) [inline, static]

determine length of L1 message

Parameters:

[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.

References tail.

static unsigned int msgb_l2len ( const struct msgb * msgb ) [inline, static]

determine length of L2 message

Parameters:

[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.

References tail.

static unsigned int msgb_l3len ( const struct msgb * msgb ) [inline, static]

determine length of L3 message

Parameters:

[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.

References tail.

uint16_t msgb_length ( const struct msgb * msg )

get length of message buffer

Parameters:

[in] msg message buffer

Returns:: length of data section in message buffer

References len.

static unsigned char* msgb_pull	(	struct msgb *	msgb,
		unsigned int	len
	)		`[inline, static]`

remove (pull) a header from the front of the message buffer

Parameters:

[in]	msgb	message buffer
[in]	len	number of octets to be pulled

Returns:: pointer to new start of msgb

This function moves the data pointer of the Message buffers further back in the message, thereby shrinking the size of the message by len bytes.

References data, and len.

static unsigned char* msgb_push	(	struct msgb *	msgb,
		unsigned int	len
	)		`[inline, static]`

prepend (push) some data to start of message

Parameters:

[in]	msgb	message buffer
[in]	len	number of bytes to pre-pend

Returns:: pointer to newly added portion at start of msgb

This function moves the data pointer of the Message buffers further to the front (by len bytes), thereby enlarging the message by 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.

References data, len, and msgb_headroom().

static unsigned char* msgb_put	(	struct msgb *	msgb,
		unsigned int	len
	)		`[inline, static]`

append data to end of message buffer

Parameters:

[in]	msgb	message buffer
[in]	len	number of bytes to append to message

Returns:: pointer to start of newly-appended data

This function will move the tail pointer of the message buffer len bytes further, thus enlarging the message by 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.

References len, msgb_tailroom(), and tail.

Referenced by gsmtap_makemsg(), msgb_put_u16(), msgb_put_u32(), and msgb_put_u8().

static void msgb_put_u16	(	struct msgb *	msgb,
		uint16_t	word
	)		`[inline, static]`

append a uint16 value to the end of the message

Parameters:

[in]	msgb	message buffer
[in]	word	unsigned 16bit byte to be appended

References msgb_put().

static void msgb_put_u32	(	struct msgb *	msgb,
		uint32_t	word
	)		`[inline, static]`

append a uint32 value to the end of the message

Parameters:

[in]	msgb	message buffer
[in]	word	unsigned 32bit byte to be appended

References msgb_put().

static void msgb_put_u8	(	struct msgb *	msgb,
		uint8_t	word
	)		`[inline, static]`

append a uint8 value to the end of the message

Parameters:

[in]	msgb	message buffer
[in]	word	unsigned 8bit byte to be appended

References msgb_put().

static void msgb_reserve	(	struct msgb *	msg,
		int	len
	)		`[inline, static]`

Increase headroom of empty msgb, reducing the tailroom.

Parameters:

[in]	msg	message buffer
[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 Message buffers during further processing.

Calling this function leads to undefined reusults if it is called on a non-empty Message buffers.

References data, len, and tail.

Referenced by msgb_alloc_headroom().

void msgb_reset ( struct msgb * msg )

Re-set all message buffer pointers.

Parameters:

[in] m message buffer that is to be resetted

This will re-set the various internal pointers into the underlying message buffer, i.e. remvoe all headroom and treat the msgb as completely empty. It also initializes the control buffer to zero.

References _data, cb, data, head, l2h, l3h, l4h, lchan, len, and tail.

void msgb_set_talloc_ctx ( void * ctx )

Set the talloc context for msgb_alloc.

Parameters:

[in] ctx talloc context to be used as root for msgb allocations

static int msgb_tailroom ( const struct msgb * msgb ) [inline, static]

determine how much tail room is left in msgb

Parameters:

[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.

References data_len, head, and tail.

Referenced by msgb_put().

Data Structures

Files

Functions

Variables

Function Documentation