similar to the ipv4 counterpart of that patch - the same
trick used to align the tail array properly.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

that way we'll be able to reuse it for compat case
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

now we can do MCAST_MSFILTER in compat ->getsockopt() without
playing silly buggers with copying things back and forth.
We can form a native struct group_filter (sans the variable-length
tail) on stack, pass that + pointer to the tail of original request
to the helper doing the bulk of the work, then do the rest of
copyout - same as the native getsockopt() does.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

pass the userland pointer to the array in its tail, so that part
gets copied out by our functions; copyout of everything else is
done in the callers.  Rationale: reuse for compat; the array
is the same in native and compat, the layout of parts before it
is different for compat.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We want to check if optname is among the MCAST_... ones; do that as
an explicit switch.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Use the new ->ndo_tunnel_ctl instead of overriding the address limit
and using ->ndo_do_ioctl just to do a pointless user copy.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Factor out a addrconf_set_sit_dstaddr helper for the actual work if we
found a SIT device, and only hold the rtnl lock around the device lookup
and that new helper, as there is no point in holding it over a
copy_from_user call.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is no point in copying the structure from userspace or looking up
a device if SIT support is not disabled and we'll eventually return
-ENODEV anyway.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Implement the ->ndo_tunnel_ctl method, and use ip_tunnel_ioctl to
handle userspace requests for the SIOCGETTUNNEL, SIOCADDTUNNEL,
SIOCCHGTUNNEL and SIOCDELTUNNEL ioctls.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Split the ioctl handler into one function per command instead of having
a all the logic sit in one giant switch statement.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

To prepare removing the global routing_ioctl hack start lifting the code
into a newly added ipv6 ->compat_ioctl handler.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Prepare for better compat ioctl handling by moving the user copy out
of ipv6_route_ioctl.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The goal is to be able to inherit the initial devconf parameters from the
current netns, ie the netns where this new netns has been created.

This is useful in a containers environment where /proc/sys is read only.
For example, if a pod is created with specifics devconf parameters and has
the capability to create netns, the user expects to get the same parameters
than his 'init_net', which is not the real init_net in this case.
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While do_ipv6_getsockopt does not call the high-level recvmsg helper,
the msghdr eventually ends up being passed to put_cmsg anyway, and thus
needs msg_control_is_user set to the proper value.

Fixes: 1f466e1f ("net: cleanly handle kernel vs user buffers for ->msg_control")
Reported-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit b121b341 ("bpf: Add PTR_TO_BTF_ID_OR_NULL
support") adds a field btf_id_or_null_non0_off to
bpf_prog->aux structure to indicate that the
first ctx argument is PTR_TO_BTF_ID reg_type and
all others are PTR_TO_BTF_ID_OR_NULL.
This approach does not really scale if we have
other different reg types in the future, e.g.,
a pointer to a buffer.

This patch enables bpf_iter targets registering ctx argument
reg types which may be different from the default one.
For example, for pointers to structures, the default reg_type
is PTR_TO_BTF_ID for tracing program. The target can register
a particular pointer type as PTR_TO_BTF_ID_OR_NULL which can
be used by the verifier to enforce accesses.
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200513180221.2949882-1-yhs@fb.com

Change func bpf_iter_unreg_target() parameter from target
name to target reg_info, similar to bpf_iter_reg_target().
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200513180220.2949737-1-yhs@fb.com

Currently bpf_iter_reg_target takes parameters from target
and allocates memory to save them. This is really not
necessary, esp. in the future we may grow information
passed from targets to bpf_iter manager.

The patch refactors the code so target reg_info
becomes static and bpf_iter manager can just take
a reference to it.
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200513180219.2949605-1-yhs@fb.com

The cipso and calipso code can set the MLS_CAT attribute on
successful parsing, even if the corresponding catmap has
not been allocated, as per current configuration and external
input.

Later, selinux code tries to access the catmap if the MLS_CAT flag
is present via netlbl_catmap_getlong(). That may cause null ptr
dereference while processing incoming network traffic.

Address the issue setting the MLS_CAT flag only if the catmap is
really allocated. Additionally let netlbl_catmap_getlong() cope
with NULL catmap.
Reported-by: NMatthew Sheets <matthew.sheets@gd-ms.com>
Fixes: 4b8feff2 ("netlabel: fix the horribly broken catmap functions")
Fixes: ceba1832 ("calipso: Set the calipso socket label to match the secattr.")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NPaul Moore <paul@paul-moore.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch added netlink and ipv6_route targets, using
the same seq_ops (except show() and minor changes for stop())
for /proc/net/{netlink,ipv6_route}.

The net namespace for these targets are the current net
namespace at file open stage, similar to
/proc/net/{netlink,ipv6_route} reference counting
the net namespace at seq_file open stage.

Since module is not supported for now, ipv6_route is
supported only if the IPV6 is built-in, i.e., not compiled
as a module. The restriction can be lifted once module
is properly supported for bpf_iter.
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175910.2476329-1-yhs@fb.com

We currently have to adjust ipv6 route gc_thresh/max_size depending
on number of cpus on a server, this makes very little sense.

If the kernels sets /proc/sys/net/ipv6/route/gc_thresh to 1024
and /proc/sys/net/ipv6/route/max_size to 4096, then we better
not track the percpu dst that our implementation uses.

Only routes not added (directly or indirectly) by the admin
should be tracked and limited.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: David Ahern <dsahern@kernel.org>
Cc: Maciej Żenczykowski <maze@google.com>
Acked-by: NWei Wang <weiwan@google.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

percpu_counter_add() uses a default batch size which is quite big
on platforms with 256 cpus. (2*256 -> 512)

This means dst_entries_get_fast() can be off by +/- 2*(nr_cpus^2)
(131072 on servers with 256 cpus)

Reduce the batch size to something more reasonable, and
add logic to ip6_dst_gc() to call dst_entries_get_slow()
before calling the _very_ expensive fib6_run_gc() function.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

We want to have a tighter control on what ports we bind to in
the BPF_CGROUP_INET{4,6}_CONNECT hooks even if it means
connect() becomes slightly more expensive. The expensive part
comes from the fact that we now need to call inet_csk_get_port()
that verifies that the port is not used and allocates an entry
in the hash table for it.

Since we can't rely on "snum || !bind_address_no_port" to prevent
us from calling POST_BIND hook anymore, let's add another bind flag
to indicate that the call site is BPF program.

v5:
* fix wrong AF_INET (should be AF_INET6) in the bpf program for v6

v3:
* More bpf_bind documentation refinements (Martin KaFai Lau)
* Add UDP tests as well (Martin KaFai Lau)
* Don't start the thread, just do socket+bind+listen (Martin KaFai Lau)

v2:
* Update documentation (Andrey Ignatov)
* Pass BIND_FORCE_ADDRESS_NO_PORT conditionally (Andrey Ignatov)
Signed-off-by: NStanislav Fomichev <sdf@google.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAndrey Ignatov <rdna@fb.com>
Acked-by: NMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200508174611.228805-5-sdf@google.com

The intent is to add an additional bind parameter in the next commit.
Instead of adding another argument, let's convert all existing
flag arguments into an extendable bit field.

No functional changes.
Signed-off-by: NStanislav Fomichev <sdf@google.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAndrey Ignatov <rdna@fb.com>
Acked-by: NMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200508174611.228805-4-sdf@google.com

This reverts commit 19bda36c:

| ipv6: add mtu lock check in __ip6_rt_update_pmtu
|
| Prior to this patch, ipv6 didn't do mtu lock check in ip6_update_pmtu.
| It leaded to that mtu lock doesn't really work when receiving the pkt
| of ICMPV6_PKT_TOOBIG.
|
| This patch is to add mtu lock check in __ip6_rt_update_pmtu just as ipv4
| did in __ip_rt_update_pmtu.

The above reasoning is incorrect.  IPv6 *requires* icmp based pmtu to work.
There's already a comment to this effect elsewhere in the kernel:

  $ git grep -p -B1 -A3 'RTAX_MTU lock'
  net/ipv6/route.c=4813=

  static int rt6_mtu_change_route(struct fib6_info *f6i, void *p_arg)
  ...
    /* In IPv6 pmtu discovery is not optional,
       so that RTAX_MTU lock cannot disable it.
       We still use this lock to block changes
       caused by addrconf/ndisc.
    */

This reverts to the pre-4.9 behaviour.

Cc: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Xin Long <lucien.xin@gmail.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NMaciej Żenczykowski <maze@google.com>
Fixes: 19bda36c ("ipv6: add mtu lock check in __ip6_rt_update_pmtu")
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The Segment Routing Header (SRH) which defines the SRv6 dataplane is defined
in RFC8754.

RFC8754 (section 4.1) defines the SR source node behavior which encapsulates
packets into an outer IPv6 header and SRH. The SR source node encodes the
full list of Segments that defines the packet path in the SRH. Then, the
first segment from list of Segments is copied into the Destination address
of the outer IPv6 header and the packet is sent to the first hop in its path
towards the destination.

If the Segment list has only one segment, the SR source node can omit the SRH
as he only segment is added in the destination address.

RFC8754 (section 4.1.1) defines the Reduced SRH, when a source does not
require the entire SID list to be preserved in the SRH. A reduced SRH does
not contain the first segment of the related SR Policy (the first segment is
the one already in the DA of the IPv6 header), and the Last Entry field is
set to n-2, where n is the number of elements in the SR Policy.

RFC8754 (section 4.3.1.1) defines the SRH processing and the logic to
validate the SRH (S09, S10, S11) which works for both reduced and
non-reduced behaviors.

This patch updates seg6_validate_srh() to validate the SRH as per RFC8754.
Signed-off-by: NAhmed Abdelsalam <ahabdels@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Implement the upcoming rev of RFC4941 (IPv6 temporary addresses):
https://tools.ietf.org/html/draft-ietf-6man-rfc4941bis-09

* Reduces the default Valid Lifetime to 2 days
  The number of extra addresses employed when Valid Lifetime was
  7 days exacerbated the stress caused on network
  elements/devices. Additionally, the motivation for temporary
  addresses is indeed privacy and reduced exposure. With a
  default Valid Lifetime of 7 days, an address that becomes
  revealed by active communication is reachable and exposed for
  one whole week. The only use case for a Valid Lifetime of 7
  days could be some application that is expecting to have long
  lived connections. But if you want to have a long lived
  connections, you shouldn't be using a temporary address in the
  first place. Additionally, in the era of mobile devices, general
  applications should nevertheless be prepared and robust to
  address changes (e.g. nodes swap wifi <-> 4G, etc.)

* Employs different IIDs for different prefixes
  To avoid network activity correlation among addresses configured
  for different prefixes

* Uses a simpler algorithm for IID generation
  No need to store "history" anywhere
Signed-off-by: NFernando Gont <fgont@si6networks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Nik reported a bug with pcpu dst cache when nexthop objects are
used illustrated by the following:
    $ ip netns add foo
    $ ip -netns foo li set lo up
    $ ip -netns foo addr add 2001:db8:11::1/128 dev lo
    $ ip netns exec foo sysctl net.ipv6.conf.all.forwarding=1
    $ ip li add veth1 type veth peer name veth2
    $ ip li set veth1 up
    $ ip addr add 2001:db8:10::1/64 dev veth1
    $ ip li set dev veth2 netns foo
    $ ip -netns foo li set veth2 up
    $ ip -netns foo addr add 2001:db8:10::2/64 dev veth2
    $ ip -6 nexthop add id 100 via 2001:db8:10::2 dev veth1
    $ ip -6 route add 2001:db8:11::1/128 nhid 100

    Create a pcpu entry on cpu 0:
    $ taskset -a -c 0 ip -6 route get 2001:db8:11::1

    Re-add the route entry:
    $ ip -6 ro del 2001:db8:11::1
    $ ip -6 route add 2001:db8:11::1/128 nhid 100

    Route get on cpu 0 returns the stale pcpu:
    $ taskset -a -c 0 ip -6 route get 2001:db8:11::1
    RTNETLINK answers: Network is unreachable

    While cpu 1 works:
    $ taskset -a -c 1 ip -6 route get 2001:db8:11::1
    2001:db8:11::1 from :: via 2001:db8:10::2 dev veth1 src 2001:db8:10::1 metric 1024 pref medium

Conversion of FIB entries to work with external nexthop objects
missed an important difference between IPv4 and IPv6 - how dst
entries are invalidated when the FIB changes. IPv4 has a per-network
namespace generation id (rt_genid) that is bumped on changes to the FIB.
Checking if a dst_entry is still valid means comparing rt_genid in the
rtable to the current value of rt_genid for the namespace.

IPv6 also has a per network namespace counter, fib6_sernum, but the
count is saved per fib6_node. With the per-node counter only dst_entries
based on fib entries under the node are invalidated when changes are
made to the routes - limiting the scope of invalidations. IPv6 uses a
reference in the rt6_info, 'from', to track the corresponding fib entry
used to create the dst_entry. When validating a dst_entry, the 'from'
is used to backtrack to the fib6_node and check the sernum of it to the
cookie passed to the dst_check operation.

With the inline format (nexthop definition inline with the fib6_info),
dst_entries cached in the fib6_nh have a 1:1 correlation between fib
entries, nexthop data and dst_entries. With external nexthops, IPv6
looks more like IPv4 which means multiple fib entries across disparate
fib6_nodes can all reference the same fib6_nh. That means validation
of dst_entries based on external nexthops needs to use the IPv4 format
- the per-network namespace counter.

Add sernum to rt6_info and set it when creating a pcpu dst entry. Update
rt6_get_cookie to return sernum if it is set and update dst_check for
IPv6 to look for sernum set and based the check on it if so. Finally,
rt6_get_pcpu_route needs to validate the cached entry before returning
a pcpu entry (similar to the rt_cache_valid calls in __mkroute_input and
__mkroute_output for IPv4).

This problem only affects routes using the new, external nexthops.

Thanks to the kbuild test robot for catching the IS_ENABLED needed
around rt_genid_ipv6 before I sent this out.

Fixes: 5b98324e ("ipv6: Allow routes to use nexthop objects")
Reported-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid Ahern <dsahern@kernel.org>
Reviewed-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Tested-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There's no callers in-tree anymore since commit 84287bb3 ("ila: add
checksum neutral map auto").
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Not much to be done here:

- add SPDX header;
- add a document title;
- mark a literal as such, in order to avoid a warning;
- add to networking/index.rst.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Current route nexthop API maintains user space compatibility
with old route API by default. Dumps and netlink notifications
support both new and old API format. In systems which have
moved to the new API, this compatibility mode cancels some
of the performance benefits provided by the new nexthop API.

This patch adds new sysctl nexthop_compat_mode which is on
by default but provides the ability to turn off compatibility
mode allowing systems to run entirely with the new routing
API. Old route API behaviour and support is not modified by this
sysctl.

Uses a single sysctl to cover both ipv4 and ipv6 following
other sysctls. Covers dumps and delete notifications as
suggested by David Ahern.
Signed-off-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Used in subsequent work to skip route delete
notifications on nexthop deletes.
Suggested-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from  userspace in common code.  This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.

As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NAndrey Ignatov <rdna@fb.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

RFC4862 5.5.3 e) prevents received Router Advertisements from reducing
the Valid Lifetime of configured addresses to less than two hours, thus
preventing hosts from reacting to the information provided by a router
that has positive knowledge that a prefix has become invalid.

This patch makes hosts honor all Valid Lifetime values, as per
draft-gont-6man-slaac-renum-06, Section 4.2. This is meant to help
mitigate the problem discussed in draft-ietf-v6ops-slaac-renum.

Note: Attacks aiming at disabling an advertised prefix via a Valid
Lifetime of 0 are not really more harmful than other attacks
that can be performed via forged RA messages, such as those
aiming at completely disabling a next-hop router via an RA that
advertises a Router Lifetime of 0, or performing a Denial of
Service (DoS) attack by advertising illegitimate prefixes via
forged PIOs.  In scenarios where RA-based attacks are of concern,
proper mitigations such as RA-Guard [RFC6105] [RFC7113] should
be implemented.
Signed-off-by: NFernando Gont <fgont@si6networks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/ila/ila_xlat.c:604:0: warning: macro "ILA_HASH_TABLE_SIZE" is not used [-Wunused-macros]
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IPSKB_XFRM_TRANSFORMED and IP6SKB_XFRM_TRANSFORMED are skb flags set by
xfrm code to tell other skb handlers that the packet has been passed
through the xfrm output functions. Simplify the code and just always
set them rather than conditionally based on netfilter enabled thus
making the flag available for other users.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit b6f61189 ("ipv6: restrict IPV6_ADDRFORM operation") fixed a
problem found by syzbot an unfortunate logic error meant that it
also broke IPV6_ADDRFORM.

Rearrange the checks so that the earlier test is just one of the series
of checks made before moving the socket from IPv6 to IPv4.

Fixes: b6f61189 ("ipv6: restrict IPV6_ADDRFORM operation")
Signed-off-by: NJohn Haxby <john.haxby@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch makes it impossible that cmpri or cmpre values are set to the
value 16 which is not possible, because these are 4 bit values. We
currently run in an overflow when assigning the value 16 to it.

According to the standard a value of 16 can be interpreted as a full
elided address which isn't possible to set as compression value. A reason
why this cannot be set is that the current ipv6 header destination address
should never show up inside the segments of the rpl header. In this case we
run in a overflow and the address will have no compression at all. Means
cmpri or compre is set to 0.

As we handle cmpri and cmpre sometimes as unsigned char or 4 bit value
inside the rpl header the current behaviour ends in an invalid header
format. This patch simple use the best compression method if we ever run
into the case that the destination address is showed up inside the rpl
segments. We avoid the overflow handling and the rpl header is still valid,
even when we have the destination address inside the rpl segments.
Signed-off-by: NAlexander Aring <alex.aring@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The variable err is being initialized with a value that is never read
and it is being updated later with a new value.  The initialization is
redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit fac6fce9 ("net: icmp6: provide input address for
traceroute6") ICMPv6 errors have source addresses from the ingress
interface. However, this overrides when source address selection is
influenced by setting preferred source addresses on routes.

This can result in ICMP errors being lost to upstream BCP38 filters
when the wrong source addresses are used, breaking path MTU discovery
and traceroute.

This patch sets the modified source address selection to only take place
when the route used has no prefsrc set.

It can be tested with:

ip link add v1 type veth peer name v2
ip netns add test
ip netns exec test ip link set lo up
ip link set v2 netns test
ip link set v1 up
ip netns exec test ip link set v2 up
ip addr add 2001:db8::1/64 dev v1 nodad
ip addr add 2001:db8::3 dev v1 nodad
ip netns exec test ip addr add 2001:db8::2/64 dev v2 nodad
ip netns exec test ip route add unreachable 2001:db8:1::1
ip netns exec test ip addr add 2001:db8:100::1 dev lo
ip netns exec test ip route add 2001:db8::1 dev v2 src 2001:db8:100::1
ip route add 2001:db8:1000::1 via 2001:db8::2
traceroute6 -s 2001:db8::1 2001:db8:1000::1
traceroute6 -s 2001:db8::3 2001:db8:1000::1
ip netns delete test

Output before:
$ traceroute6 -s 2001:db8::1 2001:db8:1000::1
traceroute to 2001:db8:1000::1 (2001:db8:1000::1), 30 hops max, 80 byte packets
 1  2001:db8::2 (2001:db8::2)  0.843 ms !N  0.396 ms !N  0.257 ms !N
$ traceroute6 -s 2001:db8::3 2001:db8:1000::1
traceroute to 2001:db8:1000::1 (2001:db8:1000::1), 30 hops max, 80 byte packets
 1  2001:db8::2 (2001:db8::2)  0.772 ms !N  0.257 ms !N  0.357 ms !N

After:
$ traceroute6 -s 2001:db8::1 2001:db8:1000::1
traceroute to 2001:db8:1000::1 (2001:db8:1000::1), 30 hops max, 80 byte packets
 1  2001:db8:100::1 (2001:db8:100::1)  8.885 ms !N  0.310 ms !N  0.174 ms !N
$ traceroute6 -s 2001:db8::3 2001:db8:1000::1
traceroute to 2001:db8:1000::1 (2001:db8:1000::1), 30 hops max, 80 byte packets
 1  2001:db8::2 (2001:db8::2)  1.403 ms !N  0.205 ms !N  0.313 ms !N

Fixes: fac6fce9 ("net: icmp6: provide input address for traceroute6")
Signed-off-by: NTim Stallard <code@timstallard.me.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fix the loop iteration by not walking over the last
iteration. The cmpri compressing value exempt the last segment. As the
code shows the last iteration will be overwritten by cmpre value
handling which is for the last segment.

I think this doesn't end in any bufferoverflows because we work on worst
case temporary buffer sizes but it ends in not best compression settings
in some cases.

Fixes: 8610c7c6 ("net: ipv6: add support for rpl sr exthdr")
Signed-off-by: NAlexander Aring <alex.aring@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>