libosmocore 0.9.6-23.20170220git32ee5af8.fc42
Osmocom core library
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Message buffers

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
 

Data Structures

struct  msgb
 Osmocom message buffer. More...
 

Macros

#define MSGB_DEBUG
 
#define MSGB_ABORT(msg, fmt, args ...)
 
#define msgb_l1(m)
 obtain L1 header of msgb
 
#define msgb_l2(m)
 obtain L2 header of msgb
 
#define msgb_l3(m)
 obtain L3 header of msgb
 
#define msgb_sms(m)
 obtain SMS header of msgb
 

Functions

struct msgbmsgb_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 msgbmsgb_dequeue (struct llist_head *queue)
 Dequeue message buffer from head of queue.
 
void msgb_reset (struct msgb *msg)
 Re-set all message buffer pointers.
 
uint16_t msgb_length (const struct msgb *msg)
 get length of message buffer
 
const char * msgb_hexdump (const struct msgb *msg)
 Return a (static) buffer containing a hexdump of the msg.
 
int msgb_resize_area (struct msgb *msg, uint8_t *area, int old_size, int new_size)
 Resize an area within an msgb.
 
struct msgbmsgb_copy (const struct msgb *msg, const char *name)
 Copy an msgb.
 
static int msgb_test_invariant (const struct msgb *msg)
 Check a message buffer for consistency.
 
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 void msgb_push_u8 (struct msgb *msg, uint8_t word)
 prepend a uint8 value to the head of the message
 
static void msgb_push_u16 (struct msgb *msg, uint16_t word)
 prepend a uint16 value to the head of the message
 
static void msgb_push_u32 (struct msgb *msg, uint32_t word)
 prepend a uint32 value to the head of the message
 
static unsigned char * msgb_pull (struct msgb *msgb, unsigned int len)
 remove (pull) a header from the front of the message buffer
 
static unsigned char * msgb_pull_to_l3 (struct msgb *msg)
 remove (pull) all headers in front of l3h from the message buffer.
 
static uint8_t msgb_pull_u8 (struct msgb *msgb)
 remove uint8 from front of message
 
static uint16_t msgb_pull_u16 (struct msgb *msgb)
 remove uint16 from front of message
 
static uint32_t msgb_pull_u32 (struct msgb *msgb)
 remove uint32 from front of message
 
static void msgb_reserve (struct msgb *msg, int len)
 Increase headroom of empty msgb, reducing the tailroom.
 
static int msgb_trim (struct msgb *msg, int len)
 Trim the msgb to a given absolute length.
 
static int msgb_l3trim (struct msgb *msg, int l3len)
 Trim the msgb to a given layer3 length.
 
static struct msgbmsgb_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
 
void * msgb_talloc_ctx_init (void *root_ctx, unsigned int pool_size)
 Initialize a msgb talloc context for msgb_alloc. Create a talloc context called "msgb". If pool_size is 0, create a named const as msgb talloc context. If pool_size is nonzero, create a talloc pool, possibly for faster msgb allocations (see talloc_pool()).
 
void msgb_set_talloc_ctx (void *ctx)
 Set the talloc context for msgb_alloc Deprecated, use msgb_talloc_ctx_init() instead.
 

Variables

void * tall_msgb_ctx = NULL
 

Detailed Description

Macro Definition Documentation

◆ MSGB_ABORT

#define MSGB_ABORT ( msg,
fmt,
args ... )
Value:
do { \
osmo_panic("msgb(%p): " fmt, msg, ## args); \
} while(0)

◆ msgb_l1

#define msgb_l1 ( m)
Value:
((void *)(m->l1h))

obtain L1 header of msgb

Referenced by msgb_l1len().

◆ msgb_l2

#define msgb_l2 ( m)
Value:
((void *)(m->l2h))

obtain L2 header of msgb

Referenced by msgb_l2len().

◆ msgb_l3

#define msgb_l3 ( m)
Value:
((void *)(m->l3h))

obtain L3 header of msgb

Referenced by msgb_l3len().

◆ msgb_sms

#define msgb_sms ( m)
Value:
((void *)(m->l4h))

obtain SMS header of msgb

Function Documentation

◆ msgb_alloc()

struct msgb * msgb_alloc ( uint16_t size,
const char * name )
extern

Allocate a new message buffer.

Parameters
[in]sizeLength in octets, including headroom
[in]nameHuman-readable name to be associated with msgb
Returns
dynamically-allocated Message buffers

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_ex(), msgb_alloc_headroom(), and msgb_copy().

◆ msgb_alloc_headroom()

static struct msgb * msgb_alloc_headroom ( int size,
int headroom,
const char * name )
inlinestatic

Allocate message buffer with specified headroom.

Parameters
[in]sizesize in bytes, including headroom
[in]headroomheadroom in bytes
[in]namehuman-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().

◆ msgb_copy()

struct msgb * msgb_copy ( const struct msgb * msg,
const char * name )
extern

Copy an msgb.

This function allocates a new msgb, copies the data buffer of msg, and adjusts the pointers (incl l1h-l4h) accordingly. The cb part is not copied.

Parameters
[in]msgThe old msgb object
[in]nameHuman-readable name to be associated with msgb

References _data, data, data_len, head, l1h, l2h, l3h, l4h, len, msgb_alloc(), and tail.

◆ msgb_data()

uint8_t * msgb_data ( const struct msgb * msg)

get pointer to data section of message buffer

Parameters
[in]msgmessage buffer
Returns
pointer to data section of message buffer

References data.

◆ msgb_dequeue()

struct msgb * msgb_dequeue ( struct llist_head * queue)
extern

Dequeue message buffer from head of queue.

Parameters
[in]queuelinked 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 llist_head queue.

References llist_del(), llist_empty(), llist_entry, and llist_head::next.

Referenced by osmo_wqueue_bfd_cb(), and osmo_wqueue_clear().

◆ msgb_enqueue()

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

Enqueue message buffer to tail of a queue.

Parameters
[in]queuelinked list header of queue
[in]msgmessage 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, and llist_add_tail().

Referenced by osmo_wqueue_enqueue().

◆ msgb_free()

void msgb_free ( struct msgb * m)
extern

Release given message buffer.

Parameters
[in]mMessage buffer to be free'd

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

◆ msgb_get()

static unsigned char * msgb_get ( struct msgb * msgb,
unsigned int len )
inlinestatic

remove data from end of message

Parameters
[in]msgbmessage buffer
[in]lennumber of bytes to remove from end

References len, msgb_length(), and tail.

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

◆ msgb_get_u16()

static uint16_t msgb_get_u16 ( struct msgb * msgb)
inlinestatic

remove uint16 from end of message

Parameters
[in]msgbmessage buffer
Returns
16bit value taken from end of msgb

References msgb_get().

◆ msgb_get_u32()

static uint32_t msgb_get_u32 ( struct msgb * msgb)
inlinestatic

remove uint32 from end of message

Parameters
[in]msgbmessage buffer
Returns
32bit value taken from end of msgb

References msgb_get().

◆ msgb_get_u8()

static uint8_t msgb_get_u8 ( struct msgb * msgb)
inlinestatic

remove uint8 from end of message

Parameters
[in]msgbmessage buffer
Returns
8bit value taken from end of msgb

References msgb_get().

◆ msgb_headlen()

static unsigned int msgb_headlen ( const struct msgb * msgb)
inlinestatic

determine the length of the header

Parameters
[in]msgbmessage 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.

◆ msgb_headroom()

static int msgb_headroom ( const struct msgb * msgb)
inlinestatic

determine the amount of headroom in msgb

Parameters
[in]msgbmessage 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().

◆ msgb_hexdump()

const char * msgb_hexdump ( const struct msgb * msg)
extern

Return a (static) buffer containing a hexdump of the msg.

Parameters
[in]msgmessage buffer
Returns
a pointer to a static char array

References ARRAY_SIZE, data, data_len, head, l1h, l2h, l3h, l4h, osmo_hexdump(), and tail.

◆ msgb_l1len()

static unsigned int msgb_l1len ( const struct msgb * msgb)
inlinestatic

determine length of L1 message

Parameters
[in]msgbmessage 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 msgb_l1, and tail.

◆ msgb_l2len()

static unsigned int msgb_l2len ( const struct msgb * msgb)
inlinestatic

determine length of L2 message

Parameters
[in]msgbmessage 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 msgb_l2, and tail.

◆ msgb_l3len()

static unsigned int msgb_l3len ( const struct msgb * msgb)
inlinestatic

determine length of L3 message

Parameters
[in]msgbmessage 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 msgb_l3, and tail.

◆ msgb_l3trim()

static int msgb_l3trim ( struct msgb * msg,
int l3len )
inlinestatic

Trim the msgb to a given layer3 length.

Parameters
[in]msgmessage buffer
[in]l3lennew layer3 length
Returns
0 in case of success, negative in case of error

References data, l3h, and msgb_trim().

◆ msgb_length()

uint16_t msgb_length ( const struct msgb * msg)

get length of message buffer

Parameters
[in]msgmessage buffer
Returns
length of data section in message buffer

References len.

Referenced by msgb_get().

◆ msgb_pull()

static unsigned char * msgb_pull ( struct msgb * msgb,
unsigned int len )
inlinestatic

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

Parameters
[in]msgbmessage buffer
[in]lennumber 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.

Referenced by msgb_pull_to_l3(), msgb_pull_u16(), msgb_pull_u32(), and msgb_pull_u8().

◆ msgb_pull_to_l3()

static unsigned char * msgb_pull_to_l3 ( struct msgb * msg)
inlinestatic

remove (pull) all headers in front of l3h from the message buffer.

Parameters
[in]msgbmessage buffer with a valid l3h
Returns
pointer to new start of msgb (l3h)

This function moves the data pointer of the Message buffers further back in the message, thereby shrinking the size of the message. l1h and l2h will be cleared.

References data, l1h, l2h, l3h, and msgb_pull().

◆ msgb_pull_u16()

static uint16_t msgb_pull_u16 ( struct msgb * msgb)
inlinestatic

remove uint16 from front of message

Parameters
[in]msgbmessage buffer
Returns
16bit value taken from end of msgb

References msgb_pull().

◆ msgb_pull_u32()

static uint32_t msgb_pull_u32 ( struct msgb * msgb)
inlinestatic

remove uint32 from front of message

Parameters
[in]msgbmessage buffer
Returns
32bit value taken from end of msgb

References msgb_pull().

◆ msgb_pull_u8()

static uint8_t msgb_pull_u8 ( struct msgb * msgb)
inlinestatic

remove uint8 from front of message

Parameters
[in]msgbmessage buffer
Returns
8bit value taken from end of msgb

References msgb_pull().

◆ msgb_push()

static unsigned char * msgb_push ( struct msgb * msgb,
unsigned int len )
inlinestatic

prepend (push) some data to start of message

Parameters
[in]msgbmessage buffer
[in]lennumber 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().

Referenced by msgb_push_u16(), msgb_push_u32(), and msgb_push_u8().

◆ msgb_push_u16()

static void msgb_push_u16 ( struct msgb * msg,
uint16_t word )
inlinestatic

prepend a uint16 value to the head of the message

Parameters
[in]msgbmessage buffer
[in]wordunsigned 16bit byte to be prepended

References msgb_push().

◆ msgb_push_u32()

static void msgb_push_u32 ( struct msgb * msg,
uint32_t word )
inlinestatic

prepend a uint32 value to the head of the message

Parameters
[in]msgbmessage buffer
[in]wordunsigned 32bit byte to be prepended

References msgb_push().

◆ msgb_push_u8()

static void msgb_push_u8 ( struct msgb * msg,
uint8_t word )
inlinestatic

prepend a uint8 value to the head of the message

Parameters
[in]msgbmessage buffer
[in]wordunsigned 8bit byte to be prepended

References msgb_push().

◆ msgb_put()

static unsigned char * msgb_put ( struct msgb * msgb,
unsigned int len )
inlinestatic

append data to end of message buffer

Parameters
[in]msgbmessage buffer
[in]lennumber 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_ex(), msgb_put_u16(), msgb_put_u32(), and msgb_put_u8().

◆ msgb_put_u16()

static void msgb_put_u16 ( struct msgb * msgb,
uint16_t word )
inlinestatic

append a uint16 value to the end of the message

Parameters
[in]msgbmessage buffer
[in]wordunsigned 16bit byte to be appended

References msgb_put().

◆ msgb_put_u32()

static void msgb_put_u32 ( struct msgb * msgb,
uint32_t word )
inlinestatic

append a uint32 value to the end of the message

Parameters
[in]msgbmessage buffer
[in]wordunsigned 32bit byte to be appended

References msgb_put().

◆ msgb_put_u8()

static void msgb_put_u8 ( struct msgb * msgb,
uint8_t word )
inlinestatic

append a uint8 value to the end of the message

Parameters
[in]msgbmessage buffer
[in]wordunsigned 8bit byte to be appended

References msgb_put().

◆ msgb_reserve()

static void msgb_reserve ( struct msgb * msg,
int len )
inlinestatic

Increase headroom of empty msgb, reducing the tailroom.

Parameters
[in]msgmessage buffer
[in]lenamount 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().

◆ msgb_reset()

void msgb_reset ( struct msgb * msg)
extern

Re-set all message buffer pointers.

Parameters
[in]msgmessage 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.

◆ msgb_resize_area()

int msgb_resize_area ( struct msgb * msg,
uint8_t * area,
int old_size,
int new_size )
extern

Resize an area within an msgb.

This resizes a sub area of the msgb data and adjusts the pointers (incl l1h-l4h) accordingly. The cb part is not updated. If the area is extended, the contents of the extension is undefined. The complete sub area must be a part of [data,tail].

Parameters
[in,out]msgThe msgb object
[in]areaA pointer to the sub-area
[in]old_sizeThe old size of the sub-area
[in]new_sizeThe new size of the sub-area
Returns
0 on success, -1 if there is not enough space to extend the area

References data, l1h, l2h, l3h, l4h, len, msgb_trim(), and tail.

◆ msgb_set_talloc_ctx()

void msgb_set_talloc_ctx ( void * ctx)

Set the talloc context for msgb_alloc Deprecated, use msgb_talloc_ctx_init() instead.

Parameters
[in]ctxtalloc context to be used as root for msgb allocations

◆ msgb_tailroom()

static int msgb_tailroom ( const struct msgb * msgb)
inlinestatic

determine how much tail room is left in msgb

Parameters
[in]msgbmessage 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().

◆ msgb_talloc_ctx_init()

void * msgb_talloc_ctx_init ( void * root_ctx,
unsigned int pool_size )

Initialize a msgb talloc context for msgb_alloc. Create a talloc context called "msgb". If pool_size is 0, create a named const as msgb talloc context. If pool_size is nonzero, create a talloc pool, possibly for faster msgb allocations (see talloc_pool()).

Parameters
[in]root_ctxtalloc context used as parent for the new "msgb" ctx.
[in]pool_sizeif nonzero, create a talloc pool of this size.
Returns
the new msgb talloc context, e.g. for reporting

◆ msgb_test_invariant()

static int msgb_test_invariant ( const struct msgb * msg)
inlinestatic

Check a message buffer for consistency.

Parameters
[in]msgmessage buffer
Returns
0 (false) if inconsistent, != 0 (true) otherwise

References data, data_len, head, l1h, l2h, l3h, l4h, len, and tail.

◆ msgb_trim()

static int msgb_trim ( struct msgb * msg,
int len )
inlinestatic

Trim the msgb to a given absolute length.

Parameters
[in]msgmessage buffer
[in]lennew total length of buffer
Returns
0 in case of success, negative in case of error

References data, data_len, len, and tail.

Referenced by msgb_l3trim(), and msgb_resize_area().