Check (before forwarding received GTP packets into the tun) if the pdp ctx
associated with the packet requested was assigned an EUA of the given IP version.
This way we avoid for instance forwarding an IPv6 packet (or sending
back a response to a Router Solicitation packet) in case the APN was
configured without IPv6 support or if the MS/SGSN didn't ask for an IPv6
while requesting an EUA.
As a side effect, this commit fixes an OSMO_ASSERT hit introduced in handle_router_mcast
in 2d6a69e69a due to a deffective MS
sending an icmpv6 Router Solicitation over IPv6 after having been
requesting and assigned an IPv4 EUA (so no IPv6 packets expected).
Before that commit, there was no crash but the message was being wrongly
answered and used an uninitialized .v6 addr field from the peer struct.
Fixes: OS#2843
Change-Id: Ib6d18a64c2b71f3bcf6cb7e3a978d2d3f9c7a79b
I'm not quite sure how I ended up doing this, but for some strange
reason the code before this commit is sending the ICMPv6 Router
Advertisements from some weird non-standard source address. This is
a violation of RFC4861 which clearly states that the source address
of router advertisements "MUST be the link-local address assigned to the
interface from which this message is sent."
Change-Id: Ib444af70fc8f0b433d371281601fd5a37b29039e
The 3GPP specs are quite strange when it comes to how an IPv6 address
or rather prefix is assigned to an IPv6 PDP context. The designated
method for allocating the IPv6 address via the PDP EUA (End User
Address) Information Element in the GTP signalling plane is *not*
used to allocate the address/prefix. Instead, the EUA is used to
allocate an "interface identifier" to the MS, which it the uses
to derive its link-local source address to send a router solicitation.
The GGSN subsequently answers witha router advertisement, advertising
a single/64 prefix, whihcthe MS then uses to generate it's real IPv6
source address for subsequent communication.
Change-Id: Icddf7d30e01d76a4784bcef5787b36f52f703a9f
Pau Espin
Harald Welte