Collaboration diagram for SIP Headers:
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Modules | |
SIP Status Codes and Reason Phrases | |
The macros and variables for the standard SIP status codes and reason phrases are defined in <sip_status.h>. | |
SIP Tags | |
SIP headers in tag item lists and tagged argument lists. | |
Request Line | |
The request line is first line in a SIP request message. | |
Status Line | |
The status line is first line in a response message. | |
Message Payload | |
The payload object contains the optional message body. | |
Separator Line | |
An empty line separates message headers from the message body (payload). | |
Unknown Headers | |
The unknown headers are handled with sip_unknown_t structure. | |
Erroneous Headers | |
The erroneous headers are stored in sip_error_t structure. | |
Call-ID Header | |
The Call-ID header uniquely identifies a particular invitation or all registrations of a particular client. | |
CSeq Header | |
The CSeq header (command sequence) uniquely identifies transactions within a dialog. | |
Contact Header | |
The Contact header contain a list of URLs used to redirect future requests. | |
Content-Length Header | |
The Content-Length header indicates the size of the message-body in decimal number of octets. | |
Date Header | |
The Date header field reflects the time when the request or response was first sent. | |
Expires Header | |
The Expires header field gives the date and time after which the message content expires. | |
From Header | |
The From header indicates the initiator of the request. | |
Max-Forwards Header | |
The Max-Forwards header is used to limit the number of proxies or gateways that can forward the request. | |
Min-Expires Header | |
The Min-Expires header is used to limit the number of proxies or gateways that can forward the request. | |
Retry-After Header | |
The Retry-After response-header field [RFC3261/20.33] can be used to indicate how long the service is expected to be unavailable or when the called party anticipates being available again. | |
Route Header | |
The Route headers is used to store the route set of a transaction. | |
Record-Route Header | |
The Record-Route headers are used to establish a route for transactions belonging to a session. | |
To Header | |
The To header field specifies the "logical" recipient of the request. | |
Via Header | |
The Via header indicates the path taken by the request so far. | |
Request-Disposition Header | |
The Request-Disposition header syntax is defined in draft-ietf-sip-callerprefs-08.txt section 10 as follows:. | |
Accept-Contact Header | |
The Accept-Contact and Reject-Contact syntax is defined in draft-ietf-sip-callerprefs-07.txt section 10 as follows:. | |
Reject-Contact Header | |
The Reject-Contact header syntax is shown with Accept-Contact Header Accept-Contact header. | |
Event Header | |
The Event header is used to indicate the which event or class of events the message contains or subscribes. | |
Allow-Event Header | |
The Allow-Event header is used to indicate which events or classes of events the notifier supports. | |
Subscription-State Header | |
The Subscription-State header is used to indicate in which state a subscription is. | |
Call-Info Header | |
The Call-Info header provides additional information about the caller or callee. | |
Error-Info Header | |
The Error-Info header provides a pointer to additional information about the error status response. | |
In-Reply-To Header | |
The In-Reply-To request header field enumerates the Call-IDs that this call references or returns. | |
Organization Header | |
The Organization header field conveys the name of the organization to which the entity issuing the request or response belongs. | |
Priority Header | |
The Priority request-header field indicates the urgency of the request as perceived by the client. | |
Server Header | |
The Server response-header field contains information about the software used by the user agent server to handle the request. | |
Subject Header | |
The Subject header provides a summary or indicates the nature of the request. | |
Timestamp Header | |
The Timestamp header describes when the client sent the request to the server, and it is used by the client to adjust its retransmission intervals. | |
User-Agent Header | |
The User-Agent header contains information about the client user agent originating the request. | |
SIP-ETag Header | |
The SIP-ETag header field identifies the published event state. | |
SIP-If-Match Header | |
The SIP-If-Match header field identifies the specific entity of event state that the request is refreshing, modifying or removing. | |
Allow Header | |
The Allow header lists the set of methods supported by the user agent generating the message. | |
Proxy-Require Header | |
The Proxy-Require header is used to indicate proxy-sensitive features that MUST be supported by the proxy. | |
Require Header | |
The Require header is used by clients to tell user agent servers about options that the client expects the server to support in order to properly process the request. | |
Supported Header | |
The Supported header enumerates all the capabilities of the client or server. | |
Unsupported Header | |
The Unsupported header lists the features not supported by the server. | |
Path Header | |
The Path header field is a SIP extension header field (RFC 3327) with syntax very similar to the Record-Route header field. | |
Service-Route Header | |
The "Service-Route" is a SIP extension header field (RFC 3608), which can contain a route vector that will direct requests through a specific sequence of proxies. | |
Accept Header | |
The Accept request-header field can be used to specify certain media types which are acceptable for the response. | |
Accept-Encoding Header | |
The Accept-Encoding header is similar to Accept, but restricts the content-codings that are acceptable in the response. | |
Accept-Language Header | |
The Accept-Language header can be used to allow the client to indicate to the server in which language it would prefer to receive reason phrases, session descriptions or status responses carried as message bodies. | |
Content-Disposition Header | |
The Content-Disposition header field describes how the message body or, in the case of multipart messages, a message body part is to be interpreted by the UAC or UAS. | |
Content-Encoding Header | |
The Content-Encoding header indicates what additional content codings have been applied to the entity-body. | |
Content-Language Header | |
The Content-Language header [H14.12] describes the natural language(s) of the intended audience for the enclosed entity. | |
Content-Type Header | |
The Content-Type header indicates the media type of the message-body sent to the recipient. | |
MIME-Version Header | |
MIME-Version header indicates what version of the MIME protocol was used to construct the message. | |
Warning Header | |
The Warning response-header field is used to carry additional information about the status of a response. | |
RAck Header | |
The RAck header indicates the sequence number of the provisional response which is being acknowledged. | |
RSeq Header | |
The RSeq header identifies provisional responses within a transaction. | |
Reason Header | |
The Reason header is used to indicate why a SIP request was issued or why a provisional response was sent. | |
Refer-To Header | |
The Refer-To header provides a URI to reference. | |
Referred-By Header | |
The Referred-By header conveys the identity of the original referrer to the referred-to party. | |
Replaces Header | |
The Replaces header indicates that a single dialog identified by the header field is to be shut down and logically replaced by the incoming INVITE in which it is contained. | |
Authorization Header | |
The Authorization header consists of credentials containing the authentication information of the user agent for the realm of the resource being requested. | |
Proxy-Authenticate Header | |
The Proxy-Authenticate header consists of a challenge that indicates the authentication scheme and parameters applicable to the proxy. | |
Proxy-Authorization Header | |
The Proxy-Authorization header consists of credentials containing the authentication information of the user agent for the proxy and/or realm of the resource being requested. | |
WWW-Authenticate Header | |
The WWW-Authenticate header consists of at least one challenge that indicates the authentication scheme(s) and parameters applicable to the Request-URI. | |
Authentication-Info Header | |
The Authentication-Info header contains either a next-nonce used by next request and/or authentication from server used in mutual authentication. | |
Proxy-Authentication-Info Header | |
The Proxy-Authentication-Info header contains either a next-nonce used by next request and/or authentication from proxy used in mutual authentication. | |
Security-Client Header | |
The Security-Client header is defined by RFC 3329, "Security Mechanism Agreement for the Session Initiation Protocol (SIP)". | |
Security-Server Header | |
The Security-Server header is defined by RFC 3329, "Security Mechanism Agreement for the Session Initiation Protocol (SIP)". | |
Security-Verify Header | |
The Security-Verify header is defined by RFC 3329, "Security Mechanism Agreement for the Session Initiation Protocol (SIP)". | |
Privacy Header | |
The Privacy header is used by User-Agent to request privacy services from the network. | |
Session-Expires Header | |
The Session-Expires header is used to convey the lifetime of the session. | |
Min-SE Header | |
The Min-SE header is used to indicate the minimum value for the session interval. | |
#define | SIP_X_INIT() |
Initializer for structure sip_X_t. | |
enum | { sip_X_hash } |
sip_X_t * | sip_X_init (sip_X_t x[1]) |
Initialize a structure sip_X_t. | |
int | sip_is_X (sip_header_t const *header) |
Test if header object is instance of sip_X_t. | |
sip_X_t * | sip_X_dup (su_home_t *home, sip_X_t const *hdr) |
Duplicate (deep copy) sip_X_t . | |
sip_X_t * | sip_X_copy (su_home_t *home, sip_X_t const *hdr) |
Copy a sip_X_t header structure. | |
sip_X_t * | sip_X_make (su_home_t *home, char const *s) |
Make a header structure sip_X_t. | |
sip_X_t * | sip_X_format (su_home_t *home, char const *fmt,...))) |
Make a X from formatting result. | |
int | sip_X_d (su_home_t *home, sip_header_t *h, char *s, int bsiz) |
Decode a header X. | |
int | sip_X_e (char buf[], int bsiz, sip_header_t const *h, int flags) |
Encode a header X. | |
msg_hclass_t | sip_X_class [] |
Header class for SIP X. | |
msg_parse_f | sip_X_d |
Parse a X. | |
msg_print_f | sip_X_e |
Print a X. |
The header structure name is generated from the header name by lowercasing the name, replacing the non-alphanumeric characters (usually just minus "-") with underscore "_" characters, and then adding prefix sip_
and suffix _t
. For instance, the contents of header "MIME-Version" is stored in a structure called sip_mime_version_t.
All header structures contain the common part, a sip_common_t structure (X_common
[]), a link to the next header in list (X_next
), and a various fields describing the header value (in this case, X_value
).
typedef struct sip_X_s { sip_common_t X_common[1]; sip_X_t *X_next; unsigned long X_value; } sip_X_t;
The X_common
is a structure sip_common_t (aka msg_common_t), which is common to each fragment and can be considered as a base class for all headers. The structure sip_common_t contains the pointers for dual-linked fragment chain (h_succ, h_prev), a pointer to header class (h_class), a pointer to the text encoding of header contents (h_data) and the length of the encoding (h_len). (X_common is an array of size 1, as it makes it easy to cast a header pointer to a pointer to sip_common_t.)
The X_next
is a pointer to another header (usually a pointer to structure of same type). If there are multiple headers with same name, like the two "Via" headers in the example above, the X_next
is used to link the second header to the first. The fragment chain cannot be used for this purpose as the headers with same name are not necessarily adjacent.
#define SIP_X_INIT | ( | ) |
Initializer for structure sip_X_t.
A static sip_X_t structure must be initialized with the SIP_X_INIT() macro. For instance,
sip_X_t sip_X = SIP_X_INIT;
int sip_is_X | ( | sip_header_t const * | header | ) | [inline] |
Test if header object is instance of sip_X_t.
The function sip_is_X() returns true (nonzero) if the header class is an instance of X object and false (zero) otherwise.
header | pointer to the header structure to be tested |
sip_X_t* sip_X_copy | ( | su_home_t * | home, | |
sip_X_t const * | hdr | |||
) |
Copy a sip_X_t header structure.
The function sip_X_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 header structure hdr.
home | memory home used to allocate new structure | |
hdr | pointer to the header structure to be duplicated |
X = sip_X_copy(home, sip->sip_X);
int sip_X_d | ( | su_home_t * | home, | |
sip_header_t * | h, | |||
char * | s, | |||
int | bsiz | |||
) |
Decode a header X.
The function sip_X_d() decodes value of the header X in the preallocated header structure h. The string s to be decoded should not contain the header name or colon. The decoding function also expects that the leading and trailing whitespace has been removed from the string s.
home | memory home used to allocate new header structure. | |
h | sip_X_t header structure | |
s | string to be decoded | |
bsiz | length of string s |
sip_X_t* sip_X_dup | ( | su_home_t * | home, | |
sip_X_t const * | hdr | |||
) |
Duplicate (deep copy) sip_X_t
.
The function sip_X_dup() duplicates 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.
home | memory home used to allocate new structure | |
hdr | header structure to be duplicated |
X = sip_X_dup(home, sip->sip_X);
int sip_X_e | ( | char | buf[], | |
int | bsiz, | |||
sip_header_t const * | h, | |||
int | flags | |||
) |
Encode a header X.
The function sip_X_e() encodes a header structure h to the given buffer buf. Even if the given buffer buf is NULL or its size bufsiz is too small to fit the encoding result, the function returns the number of characters required for the encoding.
buf | buffer to store the encoding result | |
bsiz | size of the encoding buffer | |
h | header to be encoded. | |
flags | flags controlling the encoding |
sip_X_t * sip_X_format | ( | su_home_t * | home, | |
char const * | fmt, | |||
... | ||||
) | [inline] |
Make a X from formatting result.
The function sip_X_format() makes a new X 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 uses the formatting result as the header value.
home | memory home used to allocate new header structure. | |
fmt | string used as a printf()-style format | |
... | argument list for format |
sip_X_t* sip_X_init | ( | sip_X_t | x[1] | ) | [inline] |
Initialize a structure sip_X_t.
An sip_X_t structure can be initialized with the sip_X_init() function/macro. For instance,
sip_X_t sip_X; sip_X_init(&sip_X);
sip_X_t* sip_X_make | ( | su_home_t * | home, | |
char const * | s | |||
) | [inline] |
Make a header structure sip_X_t.
The function sip_X_make() makes a new sip_X_t header structure. It allocates a new header structure, and decodes the string s as the value of the structure.
home | memory home used to allocate new header structure. | |
s | string to be decoded as value of the new header structure |
Header class for SIP X.
The header class sip_X_class defines how a SIP X is parsed and printed. It also contains methods used by SIP parser and other functions to manipulate the sip_X_t header structure.