CSeq Header [SIP Headers]

The CSeq header (command sequence) uniquely identifies transactions within a dialog. More...

Data Structures
struct	sip_cseq_s
	Structure for CSeq header. More...
Defines
#define	sip_cseq(sip)
	Access a SIP CSeq header structure sip_cseq_t from sip_t.
#define	SIP_CSEQ_INIT()
	Initializer for structure sip_cseq_t.
#define	SIPTAG_CSEQ(x)
	Tag list item for pointer to a CSeq header structure sip_cseq_t.
#define	SIPTAG_CSEQ_REF(x)
	Tag list item for reference to a CSeq header pointer.
#define	SIPTAG_CSEQ_STR(s)
	Tag list item for string with CSeq header value.
#define	SIPTAG_CSEQ_STR_REF(x)
	Tag list item for reference to a CSeq header string.
Typedefs
typedef struct sip_cseq_s	sip_cseq_t
	The structure sip_cseq_t contains representation of SIP CSeq header.
Functions
issize_t	sip_cseq_d (su_home_t *, msg_header_t *, char *s, isize_t slen)
	Parse a SIP CSeq header.
issize_t	sip_cseq_e (char b[], isize_t bsiz, msg_header_t const *h, int flags)
	Print a SIP CSeq header.
sip_cseq_t *	sip_cseq_init (sip_cseq_t x[1])
	Initialize a structure sip_cseq_t.
int	sip_is_cseq (sip_header_t const *header)
	Test if header object is instance of sip_cseq_t.
sip_cseq_t *	sip_cseq_dup (su_home_t *home, sip_cseq_t const *hdr))
	Duplicate a list of CSeq header header structures sip_cseq_t.
sip_cseq_t *	sip_cseq_copy (su_home_t *home, sip_cseq_t const *hdr))
	Copy a list of CSeq header header structures sip_cseq_t.
sip_cseq_t *	sip_cseq_make (su_home_t *home, char const *s))
	Make a CSeq header structure sip_cseq_t.
sip_cseq_t *	sip_cseq_format (su_home_t *home, char const *fmt,...)))
	Make a CSeq header from formatting result.
sip_cseq_t *	sip_cseq_create (su_home_t *home, uint32_t seq, unsigned method, char const *method_name)
	Create a CSeq header object.
Variables
msg_hclass_t	sip_cseq_class []
	Header class for CSeq header.
tag_typedef_t	siptag_cseq
	Tag for CSeq header object.
tag_typedef_t	siptag_cseq_str
	Tag for string with CSeq header value.

---

Detailed Description

The CSeq header (command sequence) uniquely identifies transactions within a dialog.

It is defined in RFC 3261 as follows:

    CSeq              =  "CSeq" HCOLON 1*DIGIT LWS Method
    Method            =  INVITEm / ACKm / OPTIONSm / BYEm
                         / CANCELm / REGISTERm
                         / extension-method
    extension-method  =  token

The parsed CSeq header is stored in sip_cseq_t structure.

---

Define Documentation

#define SIP_CSEQ_INIT

(

)

Initializer for structure sip_cseq_t.

A static sip_cseq_t structure for CSeq header must be initialized with the SIP_CSEQ_INIT() macro. For instance,

  sip_cseq_t sip_cseq = SIP_CSEQ_INIT;

#define SIPTAG_CSEQ

(

x

)

Tag list item for pointer to a CSeq header structure sip_cseq_t.

The SIPTAG_CSEQ() macro is used to include a tag item with a pointer to a sip_cseq_t structure in a tag list.

Parameters:

x

pointer to a sip_cseq_t structure, or NULL.

The corresponding tag taking reference parameter is SIPTAG_CSEQ_REF().

#define SIPTAG_CSEQ_STR

(

s

)

Tag list item for string with CSeq header value.

The SIPTAG_CSEQ_STR() macro is used to include a tag item with a string containing value of a sip_cseq_t header in a tag list.

Parameters:

s

pointer to a string containing CSeq header value, or NULL.

The string in SIPTAG_CSEQ_STR() can be converted to a sip_cseq_t header structure by giving the string s has second argument to function sip_cseq_make().

The corresponding tag taking reference parameter is SIPTAG_CSEQ_STR_REF().

---

Typedef Documentation

typedef struct sip_cseq_s sip_cseq_t

The structure sip_cseq_t contains representation of SIP CSeq header.

The sip_cseq_t is defined as follows:

 typedef struct sip_cseq_s {
   sip_common_t   cs_common[1];       // Common fragment info
   sip_error_t   *cs_next;            // Link to next (dummy)
   uint32_t       cs_seq;             // Sequence number
   sip_method_t   cs_method;          // Method enum
   char const    *cs_method_name;     // Method name
 } sip_cseq_t;

---

Function Documentation

sip_cseq_t * sip_cseq_copy	(	su_home_t *	home,
		sip_cseq_t const *	hdr
	)			[inline]

Copy a list of CSeq header header structures sip_cseq_t.

The function sip_cseq_copy() copies a header structure hdr. If the header structure hdr contains a reference (hdr->h_next) to a list of headers, all the headers in that list are copied, too. The function uses given memory home to allocate all the memory areas used to copy the list of header structure hdr.

Parameters:

	home	memory home used to allocate new structure
	hdr	pointer to the header structure to be copied

When copying, only the header structure and parameter lists attached to it are duplicated. The new header structure retains all the references to the strings within the old hdr header, including the encoding of the old header, if present.

Example

   cseq = sip_cseq_copy(home, sip->sip_cseq);

Returns:

A pointer to newly copied header structure, or NULL upon an error.

sip_cseq_t* sip_cseq_create	(	su_home_t *	home,
		uint32_t	seq,
		unsigned	method,
		char const *	method_name
	)

 Create a CSeq header object.

Create a CSeq header object.

Create a CSeq header object with the sequence number seq, method enum method and method name method_name. The memory for the header object is allocated from the memory home home.

Parameters:

	home	memory home
	seq	sequence number
	method	method enum
	method_name	method name (required if method is not well-known)

Example

The following code fragment creates a cseq object for OPTIONS request:

   sip_cseq_t *cseq;
   cseq = sip_cseq_create(home, agent->seq++, SIP_METHOD_OPTIONS);

Returns:

A pointer to newly created CSeq header object when successful or NULL upon an error.

sip_cseq_t * sip_cseq_dup	(	su_home_t *	home,
		sip_cseq_t const *	hdr
	)			[inline]

Duplicate a list of CSeq header header structures sip_cseq_t.

Duplicate a header structure hdr. If the header structure hdr contains a reference (hdr->x_next) to a list of headers, all the headers in the list are duplicated, too.

Parameters:

	home	memory home used to allocate new structure
	hdr	header structure to be duplicated

When duplicating, all parameter lists and non-constant strings attached to the header are copied, too. The function uses given memory home to allocate all the memory areas used to copy the header.

Example

   cseq = sip_cseq_dup(home, sip->sip_cseq);

Returns:

A pointer to the newly duplicated sip_cseq_t header structure, or NULL upon an error.

sip_cseq_t * sip_cseq_format	(	su_home_t *	home,
		char const *	fmt,
			...
	)			[inline]

Make a CSeq header from formatting result.

Make a new sip_cseq_t object using formatting result as its value. The function first prints the arguments according to the format fmt specified. Then it allocates a new header structure, and parses the formatting result to the structure sip_cseq_t.

Parameters:

	home	memory home used to allocate new header structure.
	fmt	string used as a printf()-style format
	...	argument list for format

Returns:

A pointer to newly makes header structure, or NULL upon an error.

sip_cseq_t* sip_cseq_init

(

sip_cseq_t

x[1]

)

[inline]

Initialize a structure sip_cseq_t.

An sip_cseq_t structure for CSeq header can be initialized with the sip_cseq_init() function/macro. For instance,

  sip_cseq_t sip_cseq;

  sip_cseq_init(&sip_cseq);

sip_cseq_t * sip_cseq_make	(	su_home_t *	home,
		char const *	s
	)			[inline]

Make a CSeq header structure sip_cseq_t.

The function sip_cseq_make() makes a new sip_cseq_t header structure. It allocates a new header structure, and decodes the string s as the value of the structure.

Parameters:

	home	memory home used to allocate new header structure.
	s	string to be decoded as value of the new header structure

Returns:

A pointer to newly maked sip_cseq_t header structure, or NULL upon an error.

int sip_is_cseq

(

sip_header_t const *

header

)

[inline]

Test if header object is instance of sip_cseq_t.

Check if the header class is an instance of CSeq header object and return true (nonzero), otherwise return false (zero).

Parameters:

header

pointer to the header structure to be tested

Return values:

	1	(true) if the header is an instance of header cseq
	0	(false) otherwise

---

Variable Documentation

msg_hclass_t sip_cseq_class[]

Header class for CSeq header.

The header class sip_cseq_class defines how a SIP CSeq header is parsed and printed. It also contains methods used by SIP parser and other functions to manipulate the sip_cseq_t header structure.