linux.git/net/ipv6, branch v6.14

Revert "gre: Fix IPv6 link-local address generation."

2025-03-20T14:46:16+00:00

This reverts commit 183185a18ff96751db52a46ccf93fff3a1f42815.

This patch broke net/forwarding/ip6gre_custom_multipath_hash.sh in some
circumstances (https://lore.kernel.org/netdev/Z9RIyKZDNoka53EO@mini-arch/).
Let's revert it while the problem is being investigated.

Fixes: 183185a18ff9 ("gre: Fix IPv6 link-local address generation.")
Signed-off-by: Guillaume Nault 
Link: https://patch.msgid.link/8b1ce738eb15dd841aab9ef888640cab4f6ccfea.1742418408.git.gnault@redhat.com
Acked-by: Stanislav Fomichev 
Signed-off-by: Paolo Abeni

net: ipv6: ioam6: fix lwtunnel_output() loop

2025-03-20T10:25:52+00:00

Fix the lwtunnel_output() reentry loop in ioam6_iptunnel when the
destination is the same after transformation. Note that a check on the
destination address was already performed, but it was not enough. This
is the example of a lwtunnel user taking care of loops without relying
only on the last resort detection offered by lwtunnel.

Fixes: 8cb3bf8bff3c ("ipv6: ioam: Add support for the ip6ip6 encapsulation")
Signed-off-by: Justin Iurman 
Link: https://patch.msgid.link/20250314120048.12569-3-justin.iurman@uliege.be
Signed-off-by: Paolo Abeni

ipv6: Set errno after ip_fib_metrics_init() in ip6_route_info_create().

2025-03-18T11:58:08+00:00

While creating a new IPv6, we could get a weird -ENOMEM when
RTA_NH_ID is set and either of the conditions below is true:

  1) CONFIG_IPV6_SUBTREES is enabled and rtm_src_len is specified
  2) nexthop_get() fails

e.g.)

  # strace ip -6 route add fe80::dead:beef:dead:beef nhid 1 from ::
  recvmsg(3, {msg_iov=[{iov_base=[...[
    {error=-ENOMEM, msg=[... [...]]},
    [{nla_len=49, nla_type=NLMSGERR_ATTR_MSG}, "Nexthops can not be used with so"...]
  ]], iov_len=32768}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 148

Let's set err explicitly after ip_fib_metrics_init() in
ip6_route_info_create().

Fixes: f88d8ea67fbd ("ipv6: Plumb support for nexthop object in a fib6_info")
Signed-off-by: Kuniyuki Iwashima 
Reviewed-by: David Ahern 
Link: https://patch.msgid.link/20250312013854.61125-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni

ipv6: Fix memleak of nhc_pcpu_rth_output in fib_check_nh_v6_gw().

2025-03-18T11:55:11+00:00

fib_check_nh_v6_gw() expects that fib6_nh_init() cleans up everything
when it fails.

Commit 7dd73168e273 ("ipv6: Always allocate pcpu memory in a fib6_nh")
moved fib_nh_common_init() before alloc_percpu_gfp() within fib6_nh_init()
but forgot to add cleanup for fib6_nh->nh_common.nhc_pcpu_rth_output in
case it fails to allocate fib6_nh->rt6i_pcpu, resulting in memleak.

Let's call fib_nh_common_release() and clear nhc_pcpu_rth_output in the
error path.

Note that we can remove the fib6_nh_release() call in nh_create_ipv6()
later in net-next.git.

Fixes: 7dd73168e273 ("ipv6: Always allocate pcpu memory in a fib6_nh")
Signed-off-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20250312010333.56001-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni

net: ipv6: fix TCP GSO segmentation with NAT

2025-03-18T10:50:22+00:00

When updating the source/destination address, the TCP/UDP checksum needs to
be updated as well.

Fixes: bee88cd5bd83 ("net: add support for segmenting TCP fraglist GSO packets")
Signed-off-by: Felix Fietkau 
Link: https://patch.msgid.link/20250311212530.91519-1-nbd@nbd.name
Signed-off-by: Paolo Abeni

gre: Fix IPv6 link-local address generation.

2025-03-13T09:17:42+00:00

Use addrconf_addr_gen() to generate IPv6 link-local addresses on GRE
devices in most cases and fall back to using add_v4_addrs() only in
case the GRE configuration is incompatible with addrconf_addr_gen().

GRE used to use addrconf_addr_gen() until commit e5dd729460ca
("ip/ip6_gre: use the same logic as SIT interfaces when computing v6LL
address") restricted this use to gretap and ip6gretap devices, and
created add_v4_addrs() (borrowed from SIT) for non-Ethernet GRE ones.

The original problem came when commit 9af28511be10 ("addrconf: refuse
isatap eui64 for INADDR_ANY") made __ipv6_isatap_ifid() fail when its
addr parameter was 0. The commit says that this would create an invalid
address, however, I couldn't find any RFC saying that the generated
interface identifier would be wrong. Anyway, since gre over IPv4
devices pass their local tunnel address to __ipv6_isatap_ifid(), that
commit broke their IPv6 link-local address generation when the local
address was unspecified.

Then commit e5dd729460ca ("ip/ip6_gre: use the same logic as SIT
interfaces when computing v6LL address") tried to fix that case by
defining add_v4_addrs() and calling it to generate the IPv6 link-local
address instead of using addrconf_addr_gen() (apart for gretap and
ip6gretap devices, which would still use the regular
addrconf_addr_gen(), since they have a MAC address).

That broke several use cases because add_v4_addrs() isn't properly
integrated into the rest of IPv6 Neighbor Discovery code. Several of
these shortcomings have been fixed over time, but add_v4_addrs()
remains broken on several aspects. In particular, it doesn't send any
Router Sollicitations, so the SLAAC process doesn't start until the
interface receives a Router Advertisement. Also, add_v4_addrs() mostly
ignores the address generation mode of the interface
(/proc/sys/net/ipv6/conf/*/addr_gen_mode), thus breaking the
IN6_ADDR_GEN_MODE_RANDOM and IN6_ADDR_GEN_MODE_STABLE_PRIVACY cases.

Fix the situation by using add_v4_addrs() only in the specific scenario
where the normal method would fail. That is, for interfaces that have
all of the following characteristics:

  * run over IPv4,
  * transport IP packets directly, not Ethernet (that is, not gretap
    interfaces),
  * tunnel endpoint is INADDR_ANY (that is, 0),
  * device address generation mode is EUI64.

In all other cases, revert back to the regular addrconf_addr_gen().

Also, remove the special case for ip6gre interfaces in add_v4_addrs(),
since ip6gre devices now always use addrconf_addr_gen() instead.

Fixes: e5dd729460ca ("ip/ip6_gre: use the same logic as SIT interfaces when computing v6LL address")
Signed-off-by: Guillaume Nault 
Reviewed-by: Ido Schimmel 
Link: https://patch.msgid.link/559c32ce5c9976b269e6337ac9abb6a96abe5096.1741375285.git.gnault@redhat.com
Signed-off-by: Paolo Abeni

net: ipv6: fix missing dst ref drop in ila lwtunnel

2025-03-06T10:08:45+00:00

Add missing skb_dst_drop() to drop reference to the old dst before
adding the new dst to the skb.

Fixes: 79ff2fc31e0f ("ila: Cache a route to translated address")
Cc: Tom Herbert 
Signed-off-by: Justin Iurman 
Link: https://patch.msgid.link/20250305081655.19032-1-justin.iurman@uliege.be
Signed-off-by: Paolo Abeni

net: ipv6: fix dst ref loop in ila lwtunnel

2025-03-06T09:48:57+00:00

This patch follows commit 92191dd10730 ("net: ipv6: fix dst ref loops in
rpl, seg6 and ioam6 lwtunnels") and, on a second thought, the same patch
is also needed for ila (even though the config that triggered the issue
was pathological, but still, we don't want that to happen).

Fixes: 79ff2fc31e0f ("ila: Cache a route to translated address")
Cc: Tom Herbert 
Signed-off-by: Justin Iurman 
Link: https://patch.msgid.link/20250304181039.35951-1-justin.iurman@uliege.be
Signed-off-by: Paolo Abeni

net: ipv6: fix dst ref loop on input in rpl lwt

2025-02-27T13:18:22+00:00

Prevent a dst ref loop on input in rpl_iptunnel.

Fixes: a7a29f9c361f ("net: ipv6: add rpl sr tunnel")
Cc: Alexander Aring 
Cc: Ido Schimmel 
Reviewed-by: Ido Schimmel 
Signed-off-by: Justin Iurman 
Signed-off-by: Paolo Abeni

net: ipv6: fix dst ref loop on input in seg6 lwt

2025-02-27T13:18:21+00:00

Prevent a dst ref loop on input in seg6_iptunnel.

Fixes: af4a2209b134 ("ipv6: sr: use dst_cache in seg6_input")
Cc: David Lebrun 
Cc: Ido Schimmel 
Reviewed-by: Ido Schimmel 
Signed-off-by: Justin Iurman 
Signed-off-by: Paolo Abeni