<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/include/linux/ipv6.h, branch v5.10-rc3</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>net: ipv6: remove unused arg exact_dif in compute_score</title>
<updated>2020-08-31T20:08:10+00:00</updated>
<author>
<name>Miaohe Lin</name>
<email>linmiaohe@huawei.com</email>
</author>
<published>2020-08-31T06:26:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=3f7d820bad6cace3ecb859bf3fa5bc56fe8bb1c6'/>
<id>3f7d820bad6cace3ecb859bf3fa5bc56fe8bb1c6</id>
<content type='text'>
The arg exact_dif is not used anymore, remove it. inet6_exact_dif_match()
is no longer needed after the above is removed, remove it too.

Signed-off-by: Miaohe Lin &lt;linmiaohe@huawei.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The arg exact_dif is not used anymore, remove it. inet6_exact_dif_match()
is no longer needed after the above is removed, remove it too.

Signed-off-by: Miaohe Lin &lt;linmiaohe@huawei.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>inet: remove inet_sk_copy_descendant()</title>
<updated>2020-08-26T14:33:19+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2020-08-26T13:50:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=24da79902efc4a8443fae09e6c8e25b515bd8db2'/>
<id>24da79902efc4a8443fae09e6c8e25b515bd8db2</id>
<content type='text'>
This is no longer used, SCTP now uses a private helper.

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This is no longer used, SCTP now uses a private helper.

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>icmp6: support rfc 4884</title>
<updated>2020-07-25T00:12:41+00:00</updated>
<author>
<name>Willem de Bruijn</name>
<email>willemb@google.com</email>
</author>
<published>2020-07-24T13:03:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=01370434df85eb76ecb1527a4466013c4aca2436'/>
<id>01370434df85eb76ecb1527a4466013c4aca2436</id>
<content type='text'>
Extend the rfc 4884 read interface introduced for ipv4 in
commit eba75c587e81 ("icmp: support rfc 4884") to ipv6.

Add socket option SOL_IPV6/IPV6_RECVERR_RFC4884.

Changes v1-&gt;v2:
  - make ipv6_icmp_error_rfc4884 static (file scope)

Signed-off-by: Willem de Bruijn &lt;willemb@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Extend the rfc 4884 read interface introduced for ipv4 in
commit eba75c587e81 ("icmp: support rfc 4884") to ipv6.

Add socket option SOL_IPV6/IPV6_RECVERR_RFC4884.

Changes v1-&gt;v2:
  - make ipv6_icmp_error_rfc4884 static (file scope)

Signed-off-by: Willem de Bruijn &lt;willemb@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: ipv6: drop duplicate word in comment</title>
<updated>2020-07-16T03:34:11+00:00</updated>
<author>
<name>Randy Dunlap</name>
<email>rdunlap@infradead.org</email>
</author>
<published>2020-07-15T16:42:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=59632b220f2d61df274ed3a14a204e941051fdad'/>
<id>59632b220f2d61df274ed3a14a204e941051fdad</id>
<content type='text'>
Drop the doubled word "by" in a comment.

Signed-off-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: netdev@vger.kernel.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Drop the doubled word "by" in a comment.

Signed-off-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: netdev@vger.kernel.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: ipv6: add support for rpl sr exthdr</title>
<updated>2020-03-30T05:30:57+00:00</updated>
<author>
<name>Alexander Aring</name>
<email>alex.aring@gmail.com</email>
</author>
<published>2020-03-27T22:00:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3'/>
<id>8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3</id>
<content type='text'>
This patch adds rpl source routing receive handling. Everything works
only if sysconf "rpl_seg_enabled" and source routing is enabled. Mostly
the same behaviour as IPv6 segmentation routing. To handle compression
and uncompression a rpl.c file is created which contains the necessary
functionality. The receive handling will also care about IPv6
encapsulated so far it's specified as possible nexthdr in RFC 6554.

Signed-off-by: Alexander Aring &lt;alex.aring@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch adds rpl source routing receive handling. Everything works
only if sysconf "rpl_seg_enabled" and source routing is enabled. Mostly
the same behaviour as IPv6 segmentation routing. To handle compression
and uncompression a rpl.c file is created which contains the necessary
functionality. The receive handling will also care about IPv6
encapsulated so far it's specified as possible nexthdr in RFC 6554.

Signed-off-by: Alexander Aring &lt;alex.aring@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: ipv6: add socket option IPV6_ROUTER_ALERT_ISOLATE</title>
<updated>2019-03-04T05:05:10+00:00</updated>
<author>
<name>Francesco Ruggeri</name>
<email>fruggeri@arista.com</email>
</author>
<published>2019-03-01T23:31:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9036b2fe092a107856edd1a3bad48b83f2b45000'/>
<id>9036b2fe092a107856edd1a3bad48b83f2b45000</id>
<content type='text'>
By default IPv6 socket with IPV6_ROUTER_ALERT socket option set will
receive all IPv6 RA packets from all namespaces.
IPV6_ROUTER_ALERT_ISOLATE socket option restricts packets received by
the socket to be only from the socket's namespace.

Signed-off-by: Maxim Martynov &lt;maxim@arista.com&gt;
Signed-off-by: Francesco Ruggeri &lt;fruggeri@arista.com&gt;
Reviewed-by: David Ahern &lt;dsahern@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
By default IPv6 socket with IPV6_ROUTER_ALERT socket option set will
receive all IPv6 RA packets from all namespaces.
IPV6_ROUTER_ALERT_ISOLATE socket option restricts packets received by
the socket to be only from the socket's namespace.

Signed-off-by: Maxim Martynov &lt;maxim@arista.com&gt;
Signed-off-by: Francesco Ruggeri &lt;fruggeri@arista.com&gt;
Reviewed-by: David Ahern &lt;dsahern@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bridge: simplify ip_mc_check_igmp() and ipv6_mc_check_mld() calls</title>
<updated>2019-01-23T01:18:08+00:00</updated>
<author>
<name>Linus Lüssing</name>
<email>linus.luessing@c0d3.blue</email>
</author>
<published>2019-01-21T06:26:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ba5ea614622dca6d675b4cc8a97270569ae13a23'/>
<id>ba5ea614622dca6d675b4cc8a97270569ae13a23</id>
<content type='text'>
This patch refactors ip_mc_check_igmp(), ipv6_mc_check_mld() and
their callers (more precisely, the Linux bridge) to not rely on
the skb_trimmed parameter anymore.

An skb with its tail trimmed to the IP packet length was initially
introduced for the following three reasons:

1) To be able to verify the ICMPv6 checksum.
2) To be able to distinguish the version of an IGMP or MLD query.
   They are distinguishable only by their size.
3) To avoid parsing data for an IGMPv3 or MLDv2 report that is
   beyond the IP packet but still within the skb.

The first case still uses a cloned and potentially trimmed skb to
verfiy. However, there is no need to propagate it to the caller.
For the second and third case explicit IP packet length checks were
added.

This hopefully makes ip_mc_check_igmp() and ipv6_mc_check_mld() easier
to read and verfiy, as well as easier to use.

Signed-off-by: Linus Lüssing &lt;linus.luessing@c0d3.blue&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch refactors ip_mc_check_igmp(), ipv6_mc_check_mld() and
their callers (more precisely, the Linux bridge) to not rely on
the skb_trimmed parameter anymore.

An skb with its tail trimmed to the IP packet length was initially
introduced for the following three reasons:

1) To be able to verify the ICMPv6 checksum.
2) To be able to distinguish the version of an IGMP or MLD query.
   They are distinguishable only by their size.
3) To avoid parsing data for an IGMPv3 or MLDv2 report that is
   beyond the IP packet but still within the skb.

The first case still uses a cloned and potentially trimmed skb to
verfiy. However, there is no need to propagate it to the caller.
For the second and third case explicit IP packet length checks were
added.

This hopefully makes ip_mc_check_igmp() and ipv6_mc_check_mld() easier
to read and verfiy, as well as easier to use.

Signed-off-by: Linus Lüssing &lt;linus.luessing@c0d3.blue&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ipv6: Add sockopt IPV6_MULTICAST_ALL analogue to IP_MULTICAST_ALL</title>
<updated>2018-09-13T15:17:27+00:00</updated>
<author>
<name>Andre Naujoks</name>
<email>nautsch2@gmail.com</email>
</author>
<published>2018-09-10T08:27:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=15033f0457dca569b284bef0c8d3ad55fb37eacb'/>
<id>15033f0457dca569b284bef0c8d3ad55fb37eacb</id>
<content type='text'>
The socket option will be enabled by default to ensure current behaviour
is not changed. This is the same for the IPv4 version.

A socket bound to in6addr_any and a specific port will receive all traffic
on that port. Analogue to IP_MULTICAST_ALL, disable this behaviour, if
one or more multicast groups were joined (using said socket) and only
pass on multicast traffic from groups, which were explicitly joined via
this socket.

Without this option disabled a socket (system even) joined to multiple
multicast groups is very hard to get right. Filtering by destination
address has to take place in user space to avoid receiving multicast
traffic from other multicast groups, which might have traffic on the same
port.

The extension of the IP_MULTICAST_ALL socketoption to just apply to ipv6,
too, is not done to avoid changing the behaviour of current applications.

Signed-off-by: Andre Naujoks &lt;nautsch2@gmail.com&gt;
Acked-By: YOSHIFUJI Hideaki &lt;yoshfuji@linux-ipv6.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The socket option will be enabled by default to ensure current behaviour
is not changed. This is the same for the IPv4 version.

A socket bound to in6addr_any and a specific port will receive all traffic
on that port. Analogue to IP_MULTICAST_ALL, disable this behaviour, if
one or more multicast groups were joined (using said socket) and only
pass on multicast traffic from groups, which were explicitly joined via
this socket.

Without this option disabled a socket (system even) joined to multiple
multicast groups is very hard to get right. Filtering by destination
address has to take place in user space to avoid receiving multicast
traffic from other multicast groups, which might have traffic on the same
port.

The extension of the IP_MULTICAST_ALL socketoption to just apply to ipv6,
too, is not done to avoid changing the behaviour of current applications.

Signed-off-by: Andre Naujoks &lt;nautsch2@gmail.com&gt;
Acked-By: YOSHIFUJI Hideaki &lt;yoshfuji@linux-ipv6.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: reevalulate autoflowlabel setting after sysctl setting</title>
<updated>2017-12-21T18:07:20+00:00</updated>
<author>
<name>Shaohua Li</name>
<email>shli@fb.com</email>
</author>
<published>2017-12-20T20:10:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=513674b5a2c9c7a67501506419da5c3c77ac6f08'/>
<id>513674b5a2c9c7a67501506419da5c3c77ac6f08</id>
<content type='text'>
sysctl.ip6.auto_flowlabels is default 1. In our hosts, we set it to 2.
If sockopt doesn't set autoflowlabel, outcome packets from the hosts are
supposed to not include flowlabel. This is true for normal packet, but
not for reset packet.

The reason is ipv6_pinfo.autoflowlabel is set in sock creation. Later if
we change sysctl.ip6.auto_flowlabels, the ipv6_pinfo.autoflowlabel isn't
changed, so the sock will keep the old behavior in terms of auto
flowlabel. Reset packet is suffering from this problem, because reset
packet is sent from a special control socket, which is created at boot
time. Since sysctl.ipv6.auto_flowlabels is 1 by default, the control
socket will always have its ipv6_pinfo.autoflowlabel set, even after
user set sysctl.ipv6.auto_flowlabels to 1, so reset packset will always
have flowlabel. Normal sock created before sysctl setting suffers from
the same issue. We can't even turn off autoflowlabel unless we kill all
socks in the hosts.

To fix this, if IPV6_AUTOFLOWLABEL sockopt is used, we use the
autoflowlabel setting from user, otherwise we always call
ip6_default_np_autolabel() which has the new settings of sysctl.

Note, this changes behavior a little bit. Before commit 42240901f7c4
(ipv6: Implement different admin modes for automatic flow labels), the
autoflowlabel behavior of a sock isn't sticky, eg, if sysctl changes,
existing connection will change autoflowlabel behavior. After that
commit, autoflowlabel behavior is sticky in the whole life of the sock.
With this patch, the behavior isn't sticky again.

Cc: Martin KaFai Lau &lt;kafai@fb.com&gt;
Cc: Eric Dumazet &lt;eric.dumazet@gmail.com&gt;
Cc: Tom Herbert &lt;tom@quantonium.net&gt;
Signed-off-by: Shaohua Li &lt;shli@fb.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
sysctl.ip6.auto_flowlabels is default 1. In our hosts, we set it to 2.
If sockopt doesn't set autoflowlabel, outcome packets from the hosts are
supposed to not include flowlabel. This is true for normal packet, but
not for reset packet.

The reason is ipv6_pinfo.autoflowlabel is set in sock creation. Later if
we change sysctl.ip6.auto_flowlabels, the ipv6_pinfo.autoflowlabel isn't
changed, so the sock will keep the old behavior in terms of auto
flowlabel. Reset packet is suffering from this problem, because reset
packet is sent from a special control socket, which is created at boot
time. Since sysctl.ipv6.auto_flowlabels is 1 by default, the control
socket will always have its ipv6_pinfo.autoflowlabel set, even after
user set sysctl.ipv6.auto_flowlabels to 1, so reset packset will always
have flowlabel. Normal sock created before sysctl setting suffers from
the same issue. We can't even turn off autoflowlabel unless we kill all
socks in the hosts.

To fix this, if IPV6_AUTOFLOWLABEL sockopt is used, we use the
autoflowlabel setting from user, otherwise we always call
ip6_default_np_autolabel() which has the new settings of sysctl.

Note, this changes behavior a little bit. Before commit 42240901f7c4
(ipv6: Implement different admin modes for automatic flow labels), the
autoflowlabel behavior of a sock isn't sticky, eg, if sysctl changes,
existing connection will change autoflowlabel behavior. After that
commit, autoflowlabel behavior is sticky in the whole life of the sock.
With this patch, the behavior isn't sticky again.

Cc: Martin KaFai Lau &lt;kafai@fb.com&gt;
Cc: Eric Dumazet &lt;eric.dumazet@gmail.com&gt;
Cc: Tom Herbert &lt;tom@quantonium.net&gt;
Signed-off-by: Shaohua Li &lt;shli@fb.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: ipv6: sysctl to specify IPv6 ND traffic class</title>
<updated>2017-11-11T06:13:02+00:00</updated>
<author>
<name>Maciej Żenczykowski</name>
<email>maze@google.com</email>
</author>
<published>2017-11-08T05:52:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2210d6b2f287d738eddf6b75f432126ce05450f8'/>
<id>2210d6b2f287d738eddf6b75f432126ce05450f8</id>
<content type='text'>
Add a per-device sysctl to specify the default traffic class to use for
kernel originated IPv6 Neighbour Discovery packets.

Currently this includes:

  - Router Solicitation (ICMPv6 type 133)
    ndisc_send_rs() -&gt; ndisc_send_skb() -&gt; ip6_nd_hdr()

  - Neighbour Solicitation (ICMPv6 type 135)
    ndisc_send_ns() -&gt; ndisc_send_skb() -&gt; ip6_nd_hdr()

  - Neighbour Advertisement (ICMPv6 type 136)
    ndisc_send_na() -&gt; ndisc_send_skb() -&gt; ip6_nd_hdr()

  - Redirect (ICMPv6 type 137)
    ndisc_send_redirect() -&gt; ndisc_send_skb() -&gt; ip6_nd_hdr()

and if the kernel ever gets around to generating RA's,
it would presumably also include:

  - Router Advertisement (ICMPv6 type 134)
    (radvd daemon could pick up on the kernel setting and use it)

Interface drivers may examine the Traffic Class value and translate
the DiffServ Code Point into a link-layer appropriate traffic
prioritization scheme.  An example of mapping IETF DSCP values to
IEEE 802.11 User Priority values can be found here:

    https://tools.ietf.org/html/draft-ietf-tsvwg-ieee-802-11

The expected primary use case is to properly prioritize ND over wifi.

Testing:
  jzem22:~# cat /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  0
  jzem22:~# echo -1 &gt; /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  -bash: echo: write error: Invalid argument
  jzem22:~# echo 256 &gt; /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  -bash: echo: write error: Invalid argument
  jzem22:~# echo 0 &gt; /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  jzem22:~# echo 255 &gt; /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  jzem22:~# cat /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  255
  jzem22:~# echo 34 &gt; /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  jzem22:~# cat /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  34

  jzem22:~# echo $[0xDC] &gt; /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  jzem22:~# tcpdump -v -i eth0 icmp6 and src host jzem22.pgc and dst host fe80::1
  tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
  IP6 (class 0xdc, hlim 255, next-header ICMPv6 (58) payload length: 24)
  jzem22.pgc &gt; fe80::1: [icmp6 sum ok] ICMP6, neighbor advertisement,
  length 24, tgt is jzem22.pgc, Flags [solicited]

(based on original change written by Erik Kline, with minor changes)

v2: fix 'suspicious rcu_dereference_check() usage'
    by explicitly grabbing the rcu_read_lock.

Cc: Lorenzo Colitti &lt;lorenzo@google.com&gt;
Signed-off-by: Erik Kline &lt;ek@google.com&gt;
Signed-off-by: Maciej Żenczykowski &lt;maze@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add a per-device sysctl to specify the default traffic class to use for
kernel originated IPv6 Neighbour Discovery packets.

Currently this includes:

  - Router Solicitation (ICMPv6 type 133)
    ndisc_send_rs() -&gt; ndisc_send_skb() -&gt; ip6_nd_hdr()

  - Neighbour Solicitation (ICMPv6 type 135)
    ndisc_send_ns() -&gt; ndisc_send_skb() -&gt; ip6_nd_hdr()

  - Neighbour Advertisement (ICMPv6 type 136)
    ndisc_send_na() -&gt; ndisc_send_skb() -&gt; ip6_nd_hdr()

  - Redirect (ICMPv6 type 137)
    ndisc_send_redirect() -&gt; ndisc_send_skb() -&gt; ip6_nd_hdr()

and if the kernel ever gets around to generating RA's,
it would presumably also include:

  - Router Advertisement (ICMPv6 type 134)
    (radvd daemon could pick up on the kernel setting and use it)

Interface drivers may examine the Traffic Class value and translate
the DiffServ Code Point into a link-layer appropriate traffic
prioritization scheme.  An example of mapping IETF DSCP values to
IEEE 802.11 User Priority values can be found here:

    https://tools.ietf.org/html/draft-ietf-tsvwg-ieee-802-11

The expected primary use case is to properly prioritize ND over wifi.

Testing:
  jzem22:~# cat /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  0
  jzem22:~# echo -1 &gt; /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  -bash: echo: write error: Invalid argument
  jzem22:~# echo 256 &gt; /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  -bash: echo: write error: Invalid argument
  jzem22:~# echo 0 &gt; /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  jzem22:~# echo 255 &gt; /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  jzem22:~# cat /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  255
  jzem22:~# echo 34 &gt; /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  jzem22:~# cat /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  34

  jzem22:~# echo $[0xDC] &gt; /proc/sys/net/ipv6/conf/eth0/ndisc_tclass
  jzem22:~# tcpdump -v -i eth0 icmp6 and src host jzem22.pgc and dst host fe80::1
  tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
  IP6 (class 0xdc, hlim 255, next-header ICMPv6 (58) payload length: 24)
  jzem22.pgc &gt; fe80::1: [icmp6 sum ok] ICMP6, neighbor advertisement,
  length 24, tgt is jzem22.pgc, Flags [solicited]

(based on original change written by Erik Kline, with minor changes)

v2: fix 'suspicious rcu_dereference_check() usage'
    by explicitly grabbing the rcu_read_lock.

Cc: Lorenzo Colitti &lt;lorenzo@google.com&gt;
Signed-off-by: Erik Kline &lt;ek@google.com&gt;
Signed-off-by: Maciej Żenczykowski &lt;maze@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
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</entry>
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