25 Aug
2014
25 Aug
'14
2:23 p.m.
When kamailio processes a request script writer can check if there any
Route header or valid R-URI or R-URI alias parameter to determine the
destination. You can check it manually maybe reusing kamailio sip parser.
As you've already said to find a destination where kamailio is going to
send a reply you can parse via header or its "received" and "rport"
parameters. Even when via doesn't have valid destination (ws/wss
transport) it has correct "received" and "rport" parameters which
kamailio adds during a request processing.
"Via" header in INVITE received from WSS client and forwarded to a
destination looks like this:
"Via: SIP/2.0/WSS
df7jal23ls0d.invalid;received=1.2.3.4;branch=z9hG4bKTp9lzCApgHsdbRUrFcZ4XTCI49EZbbDf;rport=37213"
Not really, the main context of this question is in
reference to this
thread,
https://www.mail-archive.com/sr-users@lists.sip-router.org/msg19962.html
A patched to allow network IO intercept in kamailio corex module was
add to trunk as discussed in this thread,
https://www.mail-archive.com/sr-users@lists.sip-router.org/msg20183.html
Currently i am able to compress / decompress entire sip message coming
from or going to remote endpoint in kamailio server. It works fine.
Now i want to try ITV encryption algorithm for this on-wire data.
https://github.com/mshary/itv
For this i need to keep track of remote endpoint. At this low level, i
only have raw data received from or being transmitted to remote UA,
without even the remote socket address, so i have no choice but to
look at this raw data to determine the identity of remote endpoint.
For non-WS transport, i can easily look at topmost VIA and extract
network address to use as "unique identification" of endpoint who sent
the data or would receive the data. However, for WS transport this
topmost VIA is useless static constant string. So VIA checking is
pointless (all remote endpoints will or may have same top most VIA).
So i was thinking if there is another way to do it? I thought of using
GRUU, but it is not always present, especially in SIP replies.
Thank you.
On Mon, Aug 25, 2014 at 3:24 PM, Vitaliy Aleksandrov
<vitalik.voip(a)gmail.com <mailto:vitalik.voip@gmail.com>> wrote:
On 22.08.14 03:26, Muhammad Shahzad wrote:
Sorry for putting this question on both dev and user mailing
lists, as it is a rather theoretical question and i hope some
SIP guru on either mail list will answer.
For non-WS endpoints which use TCP or UDP for SIP transport,
each upstream request has top most VIA header pointing to the
previous hop which forwarded the request to current hop while
each downstream request has top most VIA header pointing to
next hop to which it will be forwarded from current hop.
But for WS endpoints, the top most VIA has dummy static value,
so there is no way to identify who sent this request or to
whom the reply is going to.
Please note that i am not specifically interested in network
address of remote endpoint (though VIA header is suppose to
provide it), i only need to match requests and responses from
/ to a specific device using SIP v2.0 standard.
Any help is highly appreciated.
Thank you.
Can you provide an example of scenario you want to create ?
Do you want to understand how transaction and dialog matching
works in SIP ?
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