We now have a function that generates BSSGP PS and CS paging request.
It is called from the libgtp code when we receive a GTP packet from
the GGSN for a MM context that is in SUSPEND state. We then issue
a PS paging request to the Cell with the BVCI where the last RA update
was being performed.
TODO: We still don't enqueue the GTP packet (and transmit it on paging
complete), and we don't rate-limit the paging requests, i.e. every GTP packet
will trigger another paging request.
We probably also need some kind of logic that marks the phone as UNREGISTERED
if it doesn't respond to paging requests for some time.
This only works for packets that are small enough to not need
fragmentation at the SNDCP layer (dns queries, ntp and the like).
It requires libgtp built from OpenGGSN dc3744fda045f9fca83de6881176987335a309a8
or later. Plain 0.90 will NOT work.
Using this version, I could see bi-directional traffic from various
phones going all the way through BTS, OsmoSGSN, OpenGGSN and being routed
to and from the real internet. Time to celebrate...
We have to copy the sin_addr.s_addr, rather than the entire sin_addr. The
latter results in the destination interpreting it as an IPv6 address, as
the only differentiator between IPv4 and IPv6 is the size of the payload
of this IE.
* store LLC SAPI as part of PDP ctx
* store NSEI + BVCI as part of MM ctx
* export gsm48_tx_gsm_act_pdp_acc() and call it from sgsn_libgtp.c
* create and use gsm48_tx_gsm_act_pdp_rej for error cases
* print SAPI as part of VTY show pdp
libgtp of the OpenGGSN project will allow us to speak the GTPv0/v1
protocol of the interface between SGSN and GGSN.
This commit includes code for the main libgtp integration (file
descriptor, select loop, timer) as well as code to encode/send
a CREATE PDP CONTEXT request.
Harald Welte
Sylvain Munaut