Doing so should avoid the crash seen in OS#3956, where a message is
received in osmo-sgsn gtp iface after having received a DeleteCtxAccept
message where pdp and associated cbp is freed. As a result, when new
confirmation arrives, it can still be matched against an old request and
be sent to upper layers providing an already freed cbp.
With this patch, since all queued messages belonging to that pdp are
dropped, confirmation won't find a match and be discarded in libgtp.
In order to be able to drop all req messages belonging to a pdp, a new list
is added to pdp_t and qmsg_t are added to that list when inserted into the per-gsn
req transmit queue. This way upon pdp free time it's simply a
matter of iterating over that list to remove all messages.
There's no need to do same for resp queue, and it'd be actually
counter-productive, because it wouldn't be possible to detect and
discard duplicates anymore after pdp ctx has been freed.
Move static global pdp storage arrays to be per GSN. This way now
several GSN per process are supported without collisions.
* pdp_init() is defined in public API but it's actually only intended
for use (and currently only used) internally in gtp_new(). So let's
document that and re-use it for backward compatibility with now
deprecated API, where only one GSN per process is supported.
* Back pointer to gsn_t (pdp->gsn) moved from gtp.c:gtp_new() to
gtp_pdp_newpdp(), since it makes more sense to have it there. This way
backpointer is always set, even in case were app calls pdp_newpdp() API
directly instead of creating them through gtp.c, like osmo-sgsn does.
* Create new versions of required APIs with a pointer to gsn_t where the
pdp ctx is to be created/found. Some APIs receiving a pointer to a pdp
ctx can be left intact because we have a backpointer to its gsn_t.
* pdp_getpdp() is nowhere used, and makes little sense now that we have
pdpa reachable in gsn->pdpa, so let's deprecate it without adding a
* Deprecate gtp.h gtp_newpdp(), since it's nowhere used and useless
(does same as new gtp_pdp_newpdp() and doesn't allow for old_pdp to be
passed as parameter).
All addresses in struct tun_t were stored as an in_addr.
But IPv6 addresses need an in6_addr, so switch tun_t addresses
to the in64_addr wrapper struct.
This is an ABI break, as documented in TODO-RELEASE.
Fixes an out of bounds memcpy() identified by Coverity.
It might be useful for any user of libgtp who uses libosmocore so let's
make generalized version of it available as part of installable header.
GTP sequence numbers on GTP-U are optional for G-PDU type messages (i.e.
user-ip messages). Let's allow the user to specify this behavior by
a new pdu_t.tx_gpdu_seq flag. The flag is enabled by default to stay
compatible with the prior behaviour.