4 Nov
2011
4 Nov
'11
10:49 a.m.
Hi Jason,
I'm just continuing on a topic discussed few messages back in this thread.
Actually it is recommended to avoid adding new direct header hooks in
sip_msg_t structure, because it becomes too big compared with what
actually a SIP message has in terms of headers. Apart of invite which
can have between 10-20 headers in average, the rest have less number of
headers. Note that all headers are linked in a list held in
sip_msg_t->headers.
Getting a header from the list is possible with several functions,
depending whether you want the first or next header, searched by
internal ID (if that header has one) or simply by name. The prototypes
for these functions are in parser/msg_parse.h:
hdr_field_t* get_hdr(sip_msg_t *msg, enum _hdr_types_t ht);
hdr_field_t* next_sibling_hdr(hdr_field_t *hf);
hdr_field_t* get_hdr_by_name(sip_msg_t *msg, char *name, int name_len);
hdr_field_t* next_sibling_hdr_by_name(hdr_field_t *hf);
So getting my X-Header would be like:
parse_headers(msg, HDR_EOH_F, 0);
hdr = get_hdr_by_name(msg, "X-Header", strlen("X-Header"));
Some of them may be even removed from sip_msg_t (like priority or
subject) which are not common at all.
Cheers,
Daniel
On 11/4/11 6:35 AM, Jason Penton wrote:
Hey Henning,
Ahh, thanks for that, thats perfect for now!
A pity, those names should have been a little more descriptive ;)
Thanks
Jason
On Thu, Nov 3, 2011 at 3:27 PM, Henning Westerholt <hw(a)kamailio.org
<mailto:hw@kamailio.org>> wrote:
On Thursday 03 November 2011, Jason Penton wrote:
--
Daniel-Constantin Mierla -- http://www.asipto.com
Kamailio Advanced Training, Dec 5-8, Berlin: http://asipto.com/u/kat
http://linkedin.com/in/miconda -- http://twitter.com/miconda
For Asserted and preferred identities, we
don't need to parse
the content,
but in other headers I have not gotten to yet, we
may need to.
Hi Jason,
do you talk about p-asserted and p-preferred header? This are
fairly standard
headers, there are even some PVs to access them right now i think.
Please help me understand, I would have thought
from an architecture
perspective, we would populate the sip_msg structure with all
possible sip
headers as well as the parsers. What is the
reason we don't do this
currently? performance?
I'd guess the reasons is memory efficiency. The structure get
bigger and
bigger with every pointer. But for p-asserted and p-preffered,
they are
already included it seems:
struct hdr_field* pai;
struct hdr_field* ppi;
Best regards,
Henning
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