It was seen on a real pcap trace (sctp & gsmtap_log) that the kernel
stack may decide to kill the connection (sending an ABORT) if it fails
to transmit some data after a while:
ABORT Cause code: "Protocol violation (0x000d)",
Cause Information: "Association exceeded its max_retrans count".
When this occurs, the kernel sends the
MSG_NOTIFICATION,SCTP_ASSOC_CHANGE,SCTP_COMM_LOST notification when
reading from the socket with sctp_recvmsg(). This basically signals that
the socket conn is dead, and subsequent writes to it will result in
send() failures (and receive SCTP_SEND_FAILED notification upon follow
up reads).
It's important to notice that after those events, there's no other sort
of different event like SHUTDOWN coming in, so that's the time at which
we must tell the user to close the socket.
Hence, let's signal the caller that the socket is dead by returning 0,
to comply with usual recv() API.
Related: SYS#6113
Change-Id: If35efd404405f926a4a6cc45862eeadd1b04e08c
SCTP_SHUTDOWN_EVENT is a first class event, and not a subtype of
SCTP_ASSOC_CHANGE (such as SCTP_SHUTDOWN_COMP).
Related: SYS#6113
Change-Id: I7fa648142c07f63c55091d2a15b9d7312bcd4cec
Before handling of OSMO_STREAM_SCTP_MSG_FLAGS_NOTIFICATION in recent
commit (see Fixes: below), osmo_stream_srv_recv() and
internal _sctp_recvmsg_wrapper() in libosmo-netif would return either
-EAGAIN or 0 when an sctp notification was received from the kernel.
After adding handling of OSMO_STREAM_SCTP_MSG_FLAGS_NOTIFICATION, the
code paths for "rc == -EAGAIN" and "rc == 0" would not be executed
anymore since the first branch takes preference in the if-else
tree. For "rc == -EAGAIN" it's fine because the new branch superseeds
what's done on the "rc == -EAGAIN" branch. However, for the "rc == 0",
we forgot to actually destroy the connection. The "rc == 0" branch was
basically reached when SCTP_SHUTDOWN_EVENT was received because
osmo_stream_srv_recv() tried to resemble the interface of regular
recv(); let's hence check for that explicitly and destroy the conn
object (and the related hnb context in the process) when we receive
that event.
Fixes: 1de2091515
Related: SYS#6113
Change-Id: I11b6af51a58dc250975a696b98d0c0c9ff3df9e0
Sometimes an hNodeB may reconnect (SCTP INIT) using same SCTP tuple without
closing the previous conn. This is handled by the SCTP stack by means of
pushing a RESET notification up the stack to the sctp_recvmsg() user.
Let's handle this by marking the HNB as unregistered, since most
probably a HNB Register Req comes next as the upper layer state is
considered lost.
Depends: libosmo-netif.git Change-Id I0ee94846a15a23950b9d70eaaef1251267296bdd
Related: SYS#6113
Change-Id: Ib22881b1a34b1c3dd350912b3de8904917cf34ef
Otherwise, some paths calling hnb_context_release() (like failing to
transmit HNB-REGISTER-REJECT) would end up with a conn object alive with
no assigned hnb_context, which is something not wanted.
This way an alive conn object always has an associated hnb_context, and
they are only disassociated during synchronous release path.
Related: OS#5676
Change-Id: I44fea7ec74f14e0458861c92da4acf685ff695c1
It was observed that under some circumstances (after HNBAP
HNB-De-Register) we end up crashing because a connection has no HNB
assigned to it. Let's explicitly assert if that happens, in order
clarify and avoid same sort of thing happening without clear view on
what's going on.
The issue will be fixed in a follow-up patch.
Closes: OS#5676
Change-Id: I1eedab6f3ac974e942b02eaae41556f87dd8b6ba
* Use osmo_stream closed_cb to call hnb_context_release() in all cases
* Also call hnbap_free_hnbregisterrequesties() when sending hnb register
reject
Related: OS#5656
Change-Id: I3ba02b0939413c67bc8088ea1a8f2252fc2bda31
It is reported that a third-party SGSN is rejecting SCCP CR when the
SCCP message part exceeds a certain length. The solution is to first
send an SCCP CR without payload, and send the payload in a DT later.
Add config option
hnbgw
sccp cr max-payload-len <0-999999>
If the RANAP payload surpasses the given length, osmo-hnbgw will first
send an SCCP CR without payload, cache the RANAP payload, and put that
in an SCCP DT once the SCCP CC is received.
The original idea was to limit the size of the entire SCCP part of the
message, but I'm currently not sure how to determine that without
copying much of the osmo_sccp code. I figured using a limit on the RANAP
payload is sufficient. To avoid the error with above third-party SGSN,
the easy solution is to set max-payload-len to 0, so that we always get
a separate SCCP CR without payload.
Related: SYS#5968
Related: I827e081eaacfb8e76684ed1560603e6c8f896c38 (osmo-ttcn3-hacks)
Change-Id: If0c5c0a76e5230bf22871f527dcb2dbdf34d7328
Upcoming patch adds to this function. Let me first combine those four
LOGP() to a single one, use proper osmo_sccp_addr_to_str_c(OTC_SELECT).
To be able to use OTC_SELECT, switch hnbgw.c to osmo_select_main_ctx().
Related: SYS#5968
Change-Id: I1e0ea0a883e8cf65e6cfb45ed9b6f3d8fb7c59eb
osmo-hnbgw lacks support for an co-located media gateway. This makes it
virtually impossible to isolate the HNB from the core network properly.
Lets add MGCP support to osmo-hnbgw so that it can control a co-located
media gateway to relay the RTP streams between HNB and core network.
Change-Id: Ib9b62e0145184b91c56ce5d8870760bfa49cc5a4
Related: OS#5152
Pau Espin
Harald Welte
Daniel Willmann
Neels Hofmeyr
Philipp Maier