# &adminguide;

## Overview

The module implements SIP based operations over the messages processed by OpenSIPS. SIP is a text based protocol and the module provides a large set of very useful functions to manipulate the message at SIP level, e.g., inserting new headers or deleting them, check for method type, etc.

## Dependencies

### &osips; Modules

The following modules must be loaded before this module:

- No dependencies on other &osips; modules.

### External Libraries or Applications

The following libraries or applications must be installed before running &osips; with this module loaded:

- None.

## Exported Functions

### `filter_body(content_type)`

Filters multipart body by leaving out all other body parts except the first body part of given type.

Meaning of the parameters is as follows:

- content_type - Content type to be left in the body.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE.

#### `filter_body` usage

    ...
    if (has_body("multipart/mixed")) {
        if (filter_body("application/sdp") {
            remove_hf("Content-Type");
            append_hf("Content-Type: application/sdp\r\n");
        } else {
            xlog("Body part application/sdp not found\n");
        }
    }
    ...

### `append_to_reply(txt)`

Append txt as header to all replies that will be generated by OpenSIPS for this request.

Meaning of the parameters is as follows:

- txt - String which may contains pseudo-variables.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE, ERROR_ROUTE.

#### `append_to_reply` usage

    ...
    append_to_reply("Foo: bar\r\n");
    append_to_reply("Foo: $rm at $Ts\r\n");
    ...

### `append_hf(txt)`

Appends 'txt' as header after the last header field.

Meaning of the parameters is as follows:

- txt - Header field to be appended. The value can contain pseudo-variables which will be replaced at run time.

Note: Headers which are added in main route cannot be removed in further routes (e.g. failure routes). So, the idea is not to add there any headers that you might want to remove later. To add headers temporarely use the branch route because the changes you do there are per-branch.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE.

#### `append_hf` usage

    ...
    append_hf("P-hint: VOICEMAIL\r\n");
    append_hf("From-username: $fU\r\n");
    ...

### `append_hf(txt, hdr)`

Appends 'txt' as header after first 'hdr' header field.

Meaning of the parameters is as follows:

- txt - Header field to be appended. The value can contain pseudo-variables which will be replaced at run time.

- hdr - Header name after which the 'txt' is appended.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE.

#### `append_hf` usage

    ...
    append_hf("P-hint: VOICEMAIL\r\n", "Call-ID");
    append_hf("From-username: $fU\r\n", "Call-ID");
    ...

### `insert_hf(txt)`

Inserts 'txt' as header before the first header field.

Meaning of the parameters is as follows:

- txt - Header field to be inserted. The value can contain pseudo-variables which will be replaced at run time.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE.

#### `insert_hf` usage

    ...
    insert_hf("P-hint: VOICEMAIL\r\n");
    insert_hf("To-username: $tU\r\n");
    ...

### `insert_hf(txt, hdr)`

Inserts 'txt' as header before first 'hdr' header field.

Meaning of the parameters is as follows:

- txt - Header field to be inserted. The value can contain pseudo-variables which will be replaced at run time.

- hdr - Header name before which the 'txt' is inserted.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE.

#### `insert_hf` usage

    ...
    insert_hf("P-hint: VOICEMAIL\r\n", "Call-ID");
    insert_hf("To-username: $tU\r\n", "Call-ID");
    ...

### `append_urihf(prefix, suffix)`

Append header field name with original Request-URI in middle.

Meaning of the parameters is as follows:

- prefix - string (usually at least header field name).

- suffix - string (usually at least line terminator).

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE.

#### `append_urihf` usage

    ...
    append_urihf("CC-Diversion: ", "\r\n");
    ...

### `is_present_hf(hf_name)`

Return true if a header field is present in message.

The function is also able to distinguish the compact names. For exmaple From will match with f

Meaning of the parameters is as follows:

- hf_name - Header field name.(long or compact form). The hf_name parameter can have the following types:

  - string - Static header field name

  - pvar - Header field name is given as a pseudo-variable (as string value)

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE.

#### `is_present_hf` usage

    ...
    if (is_present_hf("From")) log(1, "From HF Present");
    ...

### `append_time()`

Adds a time header to the reply of the request. You must use it before functions that are likely to send a reply, e.g., save() from 'registrar' module. Header format is: Date: %a, %d %b %Y %H:%M:%S GMT, with the legend:

- %a abbreviated week of day name (locale)

- %d day of month as decimal number

- %b abbreviated month name (locale)

- %Y year with century

- %H hour

- %M minutes

- %S seconds

Return true if a header was successfully appended.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE.

#### `append_time` usage

    ...
    append_time();
    ...

### `is_method(name)`

Check if the method of the message matches the name. If name is a known method (invite, cancel, ack, bye, options, info, update, register, message, subscribe, notify, refer, prack), the function performs method ID testing (integer comparison) instead of ignore case string comparison.

The 'name' can be a list of methods in the form of 'method1|method2|...'. In this case, the function returns true if the SIP message's method is one from the list. IMPORTANT NOTE: in the list must be only methods defined in &osips; with ID (invite, cancel, ack, bye, options, info, update, register, message, subscribe, notify, refer, prack, publish; for more see: http://www.iana.org/assignments/sip-parameters).

If used for replies, the function tests the value of method field from CSeq header.

Meaning of the parameters is as follows:

- name - SIP method name

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, and BRANCH_ROUTE.

#### `is_method` usage

    ...
    if(is_method("INVITE"))
    {
        # process INVITEs here
    }
    if(is_method("OPTION|UPDATE"))
    {
        # process OPTIONs and UPDATEs here
    }
    ...

### `remove_hf(hname [,flags])`

Remove from message all headers with name hname

Returns true if at least one header is found and removed.

Meaning of the parameters is as follows:

- hname - header name to be removed. The hname parameter can have the following types:

  - string - Header name to be removed

  - pvar - Header name to be removed is the value of an existing pseudo-variable (as string value)

  - pattern - pattern to match the names of the headers to be removed; can be a simple wildcard or a regexp (see the second param too)

- flags - how to interpret the pattern from the first parameted.

  - r - pattern is a regexp

  - g - pattern is glob (shell wildcard pattern)

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE and BRANCH_ROUTE.

#### `remove_hf` usage

    ...
    if(remove_hf("User-Agent"))
    {
        # User Agent header removed
    }
    ...
    # removes X-Billing-Account, X-Billing-Price, X-Billing-rateplan, etc
    remove_hf("X-Billing*", "g");
    ...
    #removes headers by regex
    remove_hf("^X-g.+[0-9]", "r");
    ...

### `has_body()`, `has_body(mime)`

The function returns true if the SIP message has a body attached. The checked includes also the Content-Lenght header presence and value.

If a parameter is given, the mime described will be also checked against the Content-Type header.

If the SIP message has a multipart body and mime is not a multipart type , it will search through all the parts for the given type.

It will not handle multi-layer multiparts

Meaning of the parameters is as follows:

- mime - mime to be checked against the Content-Type header. If not present or 0, this check will be disabled.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE and BRANCH_ROUTE.

#### `has_body` usage

    ...
    if(has_body("application/sdp"))
    {
        # do interesting stuff here
    }
    ...

### `is_audio_on_hold()`

The function returns true if the SIP message has an SDP body attached and at least one audio stream in on hold.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE and BRANCH_ROUTE.

#### `is_audio_on_hold` usage

    ...
    if(is_audio_on_hold())
    {
        # do interesting stuff here
    }
    ...

### `is_privacy(privacy_type)`

The function returns true if the SIP message has a Privacy header field that includes the given privacy_type among its privacy values. See http://www.iana.org/assignments/sip-priv-values for possible privacy type values.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE and BRANCH_ROUTE.

#### `is_privacy` usage

    ...
    if(is_privacy("id"))
    {
        # do interesting stuff here
    }
    ...

### `strip_body(),` `strip_body(mime)`

If the message has a body, this function deletes it, correcting Content-Length. This function also deletes the Content-Type header.

If a MIME type is specified it will delete the body if it has the same type or, if the message has a multipart body it will go through the parts and delete all those with the specified type.

It will not handle multi-layer multiparts

Meaning of the parameters is as follows:

- mime - mime to be checked against the Content-Type header. If not present or 0, this check will be disabled.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `strip_body` usage

    ...
    strip_body();   #delete any body
    strip_body("multipart/related") # delete a multipart/related body
    strip_body("application/sdp") # delete all sdp bodies, even ones enclosed in multipart
    ...

### `add_body(body_text, new_content_type)`

This function can be used to add a body to a message. If a body already exists, it will be replaced with the new one. The second parameter is the content type of the new body. It is optional: in case the function is used to replace an existing body with a body of the same type, there is no need to set this parameter. If the message has no body or if the types are different, it is compulsory to set this parameter.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `add_body` usage

    ...
    add_body("Hello World!", "text/plain");
    ...

### `sipmsg_validate([flags[,result_pvar]])`

The function returns true if the SIP message is properly built according to SIP RFC3261. It verifies if the mandatory headers for each request/reply and can also check the format of the headers body.

The flags parameter received is optional and can be composed with the following values:

- 's' - checks the integrity of the SDP body, if it exists

- 'h' - checks the format and integrity of each header body.

- 'm' - don't check the Max-Forwards header.

- 'r' - checks the R-URI and whether the domain contains valid characters.

- 'f' - checks the URI of the 'From' field and whether the domain contains valid characters.

- 't' - checks the URI of the 'To' field and whether the domain contains valid characters.

- 'c' - checks the URI of the 'Contact' field.

The result_pvar parameter sets resulting pvar with text error reason in case of negative result ( easy for logging or propagating the rejection reason back to the bogus UA )

This function can return the following codes:

- 1 - the message is RFC3261 compliant and has been successfully validated.

- -1 - No SIP message

- -2 - Header Parsing error

- -3 - No Call-ID header

- -4 - No Content-Length header for transports that require it ( eg. TCP )

- -5 - Invalid Content-Length, other from the size of the actual body

- -6 - SDP body parsing error.

- -7 - No Cseq header.

- -8 - No From header.

- -9 - No To header.

- -10 - No Via header.

- -11 - Request URI parse error.

- -12 - Bad hostname in R-URI.

- -13 - No Max-Forward header.

- -14 - No Contact header.

- -15 - Path user for non-Register request.

- -16 - No allow header in 405 reply.

- -17 - No Min-Expire header in 423 reply.

- -18 - No Proxy-Authorize header in 407 reply.

- -19 - No Unsupported header in 420 reply.

- -20 - No WWW-Authorize header in 401 reply.

- -21 - No Content-Type header

- -22 - To header parse error

- -23 - From header parse error

- -24 - Bad hostname in To header

- -25 - Bad hostname in From header

- -26 - Contact header parse error

- -255 - undefined errors.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE and BRANCH_ROUTE.

#### `sipmsg_validate` usage

    ...
    if(!sipmsg_validate())
    {
    	send_reply("400", "Bad Request");
    	exit;
    }
    ...

    ...
    # checks also the SDP and headers body
    if(!sipmsg_validate("sh"))
    {
    	send_reply("400", "Bad Request/Body");
    	exit;
    }
    ...

### `codec_exists (name [,clock] )`

This function can be used to verify if a codec exists inside an sdp payload. It will search for the codec inside all streams from all sdp sessions. If it is found anywhere it will return TRUE otherwise it will return FALSE. The second parameter is optional, if it is not supplied any clockrate will match. Parameters are CASE INSENSITIVE.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `codec_exists` usage

    ...
    codec_exists("speex");
    or
    codec_exists("GSM","8000");
    ...

### `codec_delete (name [,clock] )`

This function can be used to delete a codec from inside an sdp payload. It will search for the codec inside all streams from all sdp sessions. If it is found anywhere it will be deleted from the mapping ("a=...") and from the list of indexes ("m=..."). Returns TRUE if any deletion occurred otherwise it will return FALSE. The second parameter is optional, if it is not supplied any clockrate will match and all will be deleted. Parameters are CASE INSENSITIVE.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `codec_delete` usage

    ...
    codec_delete("speex");
    or
    codec_delete("GSM","8000");
    ...

### `codec_move_up (name [,clock] )`

This function can be used to move a codec up in the list of indexes ("m=..."). It will search for the codec inside all streams from all sdp sessions. If it is found anywhere it will be moved to the top of the index list. Returns TRUE if any moves occurred otherwise it will return FALSE. The second parameter is optional, if it is not supplied any clockrate will match and all codecs will be moved to the front while preserving their original ordering. Parameters are CASE INSENSITIVE.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `codec_move_up` usage

    ...
    codec_move_up("speex");
    or
    codec_move_up("GSM","8000");
    ...

### `codec_move_down (name [,clock] )`

This function can be used to move a codec down in the list of indexes ("m=..."). It will search for the codec inside all streams from all sdp sessions. If it is found anywhere it will be moved to the back of the index list. Returns TRUE if any moves occurred otherwise it will return FALSE. The second parameter is optional, if it is not supplied any clockrate will match and all codecs will be moved to the back while preserving their original ordering. Parameters are CASE INSENSITIVE.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `codec_move_down` usage

    ...
    codec_move_down("speex");
    or
    codec_move_down("GSM","8000");
    ...

#### `codec_move_down` usage

    ...
    /*
      This example will move speex with 8000 codec to the back of the list,
      then it will erase GSM with 8000 clock, and then it will bring all
      speex codecs to the front of the list. Speex/8000 will be behind any
      other speex.
    */
    codec_move_down("speex","8000");
    codec_delete("GSM","8000");
    codec_move_up("speex");
    ...

### `codec_exists_re ( regexp )`

This function has the same effect as codec_exists ( without the clock parameter ) the only difference is that it takes a POSIX regular expression as a parameter.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `codec_exists_re` usage

    ...
    codec_exists_re("sp[a-z]*");
    ...

### `codec_delete_re ( regexp )`

This function has the same effect as codec_delete ( without the clock parameter ) the only difference is that it takes a POSIX regular expression as a parameter.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `codec_delete_re` usage

    ...
    codec_delete_re("PCMA|PCMU");
    ...

### `codec_delete_except_re ( regexp )`

This function deletes all the codecs except those specified by the regular expression.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `codec_delete_except_re` usage

    ...
    codec_delete_except_re("PCMA|PCMU");#will delete all codecs except PCMA and PCMU
    ...

### `codec_move_up_re ( regexp )`

This function has the same effect as codec_move_up ( without the clock parameter ) the only difference is that it takes a POSIX regular expression as a parameter.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `codec_move_up_re` usage

    ...
    codec_move_up_re("sp[a-z]*");
    ...

### `codec_move_down_re ( regexp )`

This function has the same effect as codec_move_down ( without the clock parameter ) the only difference is that it takes a POSIX regular expression as a parameter.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `codec_move_down_re` usage

    ...
    codec_move_down_re("sp[a-z]*");
    ...

#### `codec_move_down` usage

    ...
    /*
      This example will move speex with 8000 codec to the back of the list,
      then it will erase GSM with 8000 clock, and then it will bring all
      speex codecs to the front of the list. Speex/8000 will be behind any
      other speex.
    */
    codec_move_down("speex","8000");
    codec_delete("GSM","8000");
    codec_move_up("speex");
    ...

### `change_reply_status(code, reason)`

Intercept a SIP reply (in any onreply_route) and change its status code and reason phrase prior to propogating it.

Meaning of the parameters is as follows:

- code - Status code.

- reason - Reason phrase.

This function can be used from ONREPLY_ROUTE.

#### `change_reply_status` usage

    ...
    onreply_route {
        if ($rs == "603") {
            change_reply_status("404", "Not Found");
            exit;
        }
    }
    ...

### `stream_exists(regexp)`

This function can be used to verify if a stream exists inside an sdp payload. It will search for the stream inside all sdp sessions. If it is found anywhere it will return TRUE otherwise it will return FALSE.

Meaning of the parameters is as follows:

- regexp - a POSIX regular expression to match the stream media name.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `stream_exists` usage

    ...
    # check for FAX
    stream_exists("image");
    ...

### `stream_delete(regexp)`

This function can be used to delete a whole stream from inside an sdp payload. It will search for the stream inside all sdp sessions. If it is found anywhere it will be deleted along with all attributes Returns TRUE if any deletion occurred otherwise it will return FALSE.

Meaning of the parameters is as follows:

- regexp - a POSIX regular expression to match the stream media name.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `stream_delete` usage

    ...
    # prevent usage of video
    stream_delete("video");
    ...

## Known Limitations

Search functions are applied to the current message so modifications made to the sdp will be visible to the codec_exists functions( e.g. after calling codec_delete("speex") , codec_exists("speex") will return false ).