linux/include/net
Dimitris Michailidis 90427ef5d2 ipv6: fix flow labels when the traffic class is non-0
ip6_make_flowlabel() determines the flow label for IPv6 packets. It's
supposed to be passed a flow label, which it returns as is if non-0 and
in some other cases, otherwise it calculates a new value.

The problem is callers often pass a flowi6.flowlabel, which may also
contain traffic class bits. If the traffic class is non-0
ip6_make_flowlabel() mistakes the non-0 it gets as a flow label and
returns the whole thing. Thus it can return a 'flow label' longer than
20b and the low 20b of that is typically 0 resulting in packets with 0
label. Moreover, different packets of a flow may be labeled differently.
For a TCP flow with ECN non-payload and payload packets get different
labels as exemplified by this pair of consecutive packets:

(pure ACK)
Internet Protocol Version 6, Src: 2002:af5:11a3::, Dst: 2002:af5:11a2::
    0110 .... = Version: 6
    .... 0000 0000 .... .... .... .... .... = Traffic Class: 0x00 (DSCP: CS0, ECN: Not-ECT)
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0)
        .... .... ..00 .... .... .... .... .... = Explicit Congestion Notification: Not ECN-Capable Transport (0)
    .... .... .... 0001 1100 1110 0100 1001 = Flow Label: 0x1ce49
    Payload Length: 32
    Next Header: TCP (6)

(payload)
Internet Protocol Version 6, Src: 2002:af5:11a3::, Dst: 2002:af5:11a2::
    0110 .... = Version: 6
    .... 0000 0010 .... .... .... .... .... = Traffic Class: 0x02 (DSCP: CS0, ECN: ECT(0))
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0)
        .... .... ..10 .... .... .... .... .... = Explicit Congestion Notification: ECN-Capable Transport codepoint '10' (2)
    .... .... .... 0000 0000 0000 0000 0000 = Flow Label: 0x00000
    Payload Length: 688
    Next Header: TCP (6)

This patch allows ip6_make_flowlabel() to be passed more than just a
flow label and has it extract the part it really wants. This was simpler
than modifying the callers. With this patch packets like the above become

Internet Protocol Version 6, Src: 2002:af5:11a3::, Dst: 2002:af5:11a2::
    0110 .... = Version: 6
    .... 0000 0000 .... .... .... .... .... = Traffic Class: 0x00 (DSCP: CS0, ECN: Not-ECT)
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0)
        .... .... ..00 .... .... .... .... .... = Explicit Congestion Notification: Not ECN-Capable Transport (0)
    .... .... .... 1010 1111 1010 0101 1110 = Flow Label: 0xafa5e
    Payload Length: 32
    Next Header: TCP (6)

Internet Protocol Version 6, Src: 2002:af5:11a3::, Dst: 2002:af5:11a2::
    0110 .... = Version: 6
    .... 0000 0010 .... .... .... .... .... = Traffic Class: 0x02 (DSCP: CS0, ECN: ECT(0))
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0)
        .... .... ..10 .... .... .... .... .... = Explicit Congestion Notification: ECN-Capable Transport codepoint '10' (2)
    .... .... .... 1010 1111 1010 0101 1110 = Flow Label: 0xafa5e
    Payload Length: 688
    Next Header: TCP (6)

Signed-off-by: Dimitris Michailidis <dmichail@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-31 13:16:59 -05:00
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caif
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tc_act
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af_rxrpc.h
af_unix.h
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ah.h
arp.h
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ax25.h
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bond_3ad.h
bond_alb.h
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bonding.h
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calipso.h
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cfg80211.h cfg80211/mac80211: fix BSS leaks when abandoning assoc attempts 2016-12-09 12:57:49 +01:00
cfg802154.h
checksum.h Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
cipso_ipv4.h
cls_cgroup.h
codel_impl.h
codel_qdisc.h
codel.h
compat.h
datalink.h
dcbevent.h
dcbnl.h
devlink.h
dn_dev.h
dn_fib.h
dn_neigh.h
dn_nsp.h
dn_route.h
dn.h
dsa.h
dsfield.h
dst_cache.h
dst_metadata.h
dst_ops.h
dst.h
esp.h
ethoc.h
fib_rules.h
firewire.h
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flow.h Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-12 19:25:04 -08:00
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geneve.h
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icmp.h
ieee80211_radiotap.h
ieee802154_netdev.h
if_inet6.h ipv6 addrconf: Implemented enhanced DAD (RFC7527) 2016-12-03 23:21:37 -05:00
ila.h
inet_common.h
inet_connection_sock.h inet: Fix get port to handle zero port number with soreuseport set 2016-12-17 11:13:19 -05:00
inet_ecn.h
inet_frag.h
inet_hashtables.h
inet_sock.h
inet_timewait_sock.h
inet6_connection_sock.h inet: Fix get port to handle zero port number with soreuseport set 2016-12-17 11:13:19 -05:00
inet6_hashtables.h
inetpeer.h
ip_fib.h ipv4: fib: Replay events when registering FIB notifier 2016-12-03 19:29:35 -05:00
ip_tunnels.h
ip_vs.h
ip.h
ip6_checksum.h
ip6_fib.h
ip6_route.h
ip6_tunnel.h
ipcomp.h
ipconfig.h
ipv6.h ipv6: fix flow labels when the traffic class is non-0 2017-01-31 13:16:59 -05:00
ipx.h
iw_handler.h
kcm.h
l3mdev.h
lapb.h
lib80211.h
llc_c_ac.h
llc_c_ev.h
llc_c_st.h
llc_conn.h
llc_if.h
llc_pdu.h
llc_s_ac.h
llc_s_ev.h
llc_s_st.h
llc_sap.h
llc.h
lwtunnel.h net: Specify the owning module for lwtunnel ops 2017-01-24 16:21:36 -05:00
mac80211.h
mac802154.h
mip6.h
mld.h
mpls_iptunnel.h
mpls.h
mrp.h
ncsi.h
ndisc.h ipv6 addrconf: Implemented enhanced DAD (RFC7527) 2016-12-03 23:21:37 -05:00
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net_namespace.h
net_ratelimit.h
netevent.h
netlabel.h
netlink.h netlink: revert broken, broken "2-clause nla_ok()" 2016-12-13 14:54:44 -05:00
netprio_cgroup.h
netrom.h
nexthop.h
nl802154.h
p8022.h
ping.h
pkt_cls.h
pkt_sched.h
pptp.h
protocol.h
psnap.h
raw.h
rawv6.h
red.h ktime: Get rid of the union 2016-12-25 17:21:22 +01:00
regulatory.h
request_sock.h
rose.h
route.h
rtnetlink.h
sch_generic.h net_sched: gen_estimator: complete rewrite of rate estimators 2016-12-05 15:21:59 -05:00
scm.h
secure_seq.h
seg6_hmac.h
seg6.h
slhc_vj.h
snmp.h
sock_reuseport.h
sock.h ktime: Get rid of the union 2016-12-25 17:21:22 +01:00
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stp.h
strparser.h
switchdev.h
tcp_states.h
tcp.h ipv4: Namespaceify tcp_tw_reuse knob 2016-12-27 12:28:07 -05:00
timewait_sock.h
transp_v6.h
tso.h
udp_tunnel.h
udp.h
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vxlan.h
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x25.h
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xfrm.h