Currently the UDPv6 early demux rx code path lacks some mandatory
checks, already implemented into the normal RX code path - namely
the checksum conversion and no_check6_rx check.
Similar to the previous commit, we move the common processing to
an UDPv6 specific helper and call it from both edemux code path
and normal code path. In respect to the UDPv4, we need to add an
explicit check for non zero csum according to no_check6_rx value.
Reported-by: Jianlin Shi <jishi@redhat.com>
Suggested-by: Xin Long <lucien.xin@gmail.com>
Fixes: c9f2c1ae12 ("udp6: fix socket leak on early demux")
Fixes: 2abb7cdc0d ("udp: Add support for doing checksum unnecessary conversion")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
commit 2abb7cdc0d ("udp: Add support for doing checksum
unnecessary conversion") left out the early demux path for
connected sockets. As a result IP_CMSG_CHECKSUM gives wrong
values for such socket when GRO is not enabled/available.
This change addresses the issue by moving the csum conversion to a
common helper and using such helper in both the default and the
early demux rx path.
Fixes: 2abb7cdc0d ("udp: Add support for doing checksum unnecessary conversion")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The batadv interfaces are virtual interfaces which just tunnel the traffic
over other ethernet compatible interfaces. It doesn't need serialization
during the tx phase and is using RCU for most of its internal
datastructures. Since it doesn't have actual queues which could be locked
independently, the throughput gets significantly reduced by the extra lock
in the core net code.
8 parallel TCP connections forwarded by an IPQ4019 based hardware over
5GHz could reach:
* without LLTX: 349 Mibit/s
* with LLTX: 563 Mibit/s
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
B.A.T.M.A.N. IV requires the number of rebroadcast from a neighboring
originator. These statistics are gathered per interface which transmitted
the OGM (and then received it again). Since an originator is not interface
specific, a resizable array was used in each originator.
This resizable array had an entry for each interface and had to be resizes
(for all OGMs) when the number of active interface was modified. This could
cause problems when a large number of interface is added and not enough
continuous memory is available to allocate the array.
There is already a per interface originator structure "batadv_orig_ifinfo"
which can be used to store this information.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
A private debug logging infrastructure is currently provided via
$debug_fs/batman_adv/*/log when CONFIG_BATMAN_ADV_DEBUG is enabled. This is
not well integrated in the rest of the tracing infrastructure of the
kernel.
Other components (like mac80211 or ath10k) allow to gather the debug
messages using generic trace events which are better integrated. This makes
it possible to interact with them using the existing userspace tools.
The tracepoint batadv:batadv_dbg will now be available when
CONFIG_BATMAN_ADV_DEBUG and CONFIG_BATMAN_ADV_TRACING is activated. The log
level mask is still used for filtering as usual.
A full system trace for offline parsing can be created (and read) using:
$ batctl ll all
$ trace-cmd record -e batadv:batadv_dbg
$ trace-cmd report
The same can also be done without recording to a file
$ batctl ll all
$ trace-cmd stream -e batadv:batadv_dbg
The trace infrastructure is especially helpful when tracing processes:
$ batctl ll all
$ ./tools/perf/perf trace --event "batadv:*" batctl p 10.204.32.1
0.000 batadv:batadv_dbg:batman_adv bat0 Parsing outgoing ARP REQUEST
0.045 batadv:batadv_dbg:batman_adv bat0 ARP MSG = [src: a2:64:14:53:f8:22-10.204.32.185 dst: 00:00:00:00:00:00-10.204.32.1]
0.067 batadv:batadv_dbg:batman_adv bat0 Entry updated: 10.204.32.185 a2:64:14:53:f8:22 (vid: -1)
0.099 batadv:batadv_dbg:batman_adv bat0 batadv_dat_select_candidates(): IP=10.204.32.1 hash(IP)=48902
0.757 batadv:batadv_dbg:batman_adv bat0 dat_select_candidates() 0: selected fe:2c:91:68:29:2b addr=48977 dist=65460
1.178 batadv:batadv_dbg:batman_adv bat0 dat_select_candidates() 1: selected fe:81:ab:c5:e3:03 addr=49181 dist=65256
1.809 batadv:batadv_dbg:batman_adv bat0 dat_select_candidates() 2: selected 66:25:a7:48:37:fb addr=49328 dist=65109
1.828 batadv:batadv_dbg:batman_adv bat0 DHT_SEND for 10.204.32.1
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Adds a hook for programs of type BPF_PROG_TYPE_FLOW_DISSECTOR and
attach type BPF_FLOW_DISSECTOR that is executed in the flow dissector
path. The BPF program is per-network namespace.
Signed-off-by: Petar Penkov <ppenkov@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
CONFIG_BATMAN_ADV_DEBUGFS is disabled by default because debugfs is not
supported for batman-adv interfaces in any non-default netns. Any remaining
users of this interface should still be informed about the deprecation and
the generic netlink alternative.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
As reported by Reobert O'Callahan, since Viro's commit to kill
dev_ifsioc() we attempt to copy too much data in compat mode,
which may lead to EFAULT when the 32-bit version of struct ifreq
sits at/near the end of a page boundary, and the next page isn't
mapped.
Fix this by passing the approprate compat/non-compat size to copy
and using that, as before the dev_ifsioc() removal. This works
because only the embedded "struct ifmap" has different size, and
this is only used in SIOCGIFMAP/SIOCSIFMAP which has a different
handler. All other parts of the union are naturally compatible.
This fixes https://bugzilla.kernel.org/show_bug.cgi?id=199469.
Fixes: bf4405737f ("kill dev_ifsioc()")
Reported-by: Robert O'Callahan <robert@ocallahan.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Replace "fallthru" with a proper "fall through" annotation.
This fix is part of the ongoing efforts to enabling
-Wimplicit-fallthrough
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When splitting a GSO segment that consists of encapsulated packets, the
skb->mac_len of the segments can end up being set wrong, causing packet
drops in particular when using act_mirred and ifb interfaces in
combination with a qdisc that splits GSO packets.
This happens because at the time skb_segment() is called, network_header
will point to the inner header, throwing off the calculation in
skb_reset_mac_len(). The network_header is subsequently adjust by the
outer IP gso_segment handlers, but they don't set the mac_len.
Fix this by adding skb_reset_mac_len() calls to both the IPv4 and IPv6
gso_segment handlers, after they modify the network_header.
Many thanks to Eric Dumazet for his help in identifying the cause of
the bug.
Acked-by: Dave Taht <dave.taht@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
When splitting a GSO segment that consists of encapsulated packets, the
skb->mac_len of the segments can end up being set wrong, causing packet
drops in particular when using act_mirred and ifb interfaces in
combination with a qdisc that splits GSO packets.
This happens because at the time skb_segment() is called, network_header
will point to the inner header, throwing off the calculation in
skb_reset_mac_len(). The network_header is subsequently adjust by the
outer IP gso_segment handlers, but they don't set the mac_len.
Fix this by adding skb_reset_mac_len() calls to both the IPv4 and IPv6
gso_segment handlers, after they modify the network_header.
Many thanks to Eric Dumazet for his help in identifying the cause of
the bug.
Acked-by: Dave Taht <dave.taht@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Johan Hedberg says:
====================
pull request: bluetooth 2018-09-13
A few Bluetooth fixes for the 4.19-rc series:
- Fixed rw_semaphore leak in hci_ldisc
- Fixed local Out-of-Band pairing data handling
Let me know if there are any issues pulling. Thanks.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This contains key material in crypto_send_aes_gcm_128 and
crypto_recv_aes_gcm_128.
Introduce union tls_crypto_context, and replace the two identical
unions directly embedded in struct tls_context with it. We can then
use this union to clean up the memory in the new tls_ctx_free()
function.
Fixes: 3c4d755915 ("tls: kernel TLS support")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
There's no need to copy the key to an on-stack buffer before calling
crypto_aead_setkey().
Fixes: 3c4d755915 ("tls: kernel TLS support")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Update 'confirmed' timestamp when ARP packet is received. It shouldn't
affect locktime logic and anyway entry can be confirmed by any higher-layer
protocol. Thus it makes sense to confirm it when ARP packet is received.
Fixes: 77d7123342 ("neighbour: update neigh timestamps iff update is effective")
Signed-off-by: Vasily Khoruzhick <vasilykh@arista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When we delete a chain of filters, we need to notify
user-space we are deleting each filters in this chain
too.
Fixes: 32a4f5ecd7 ("net: sched: introduce chain object to uapi")
Cc: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
llc_sap_close() is called by llc_sap_put() which
could be called in BH context in llc_rcv(). We can't
block in BH.
There is no reason to block it here, kfree_rcu() should
be sufficient.
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In inet6_rtm_getroute, since Commit 93531c6743 ("net/ipv6: separate
handling of FIB entries from dst based routes"), it has used rt->from
to dump route info instead of rt.
However for some route like cache, some of its information like flags
or gateway is not the same as that of the 'from' one. It caused 'ip
route get' to dump the wrong route information.
In Jianlin's testing, the output information even lost the expiration
time for a pmtu route cache due to the wrong fib6_flags.
So change to use rt6_info members for dst addr, src addr, flags and
gateway when it tries to dump a route entry without fibmatch set.
v1->v2:
- not use rt6i_prefsrc.
- also fix the gw dump issue.
Fixes: 93531c6743 ("net/ipv6: separate handling of FIB entries from dst based routes")
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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 <nautsch2@gmail.com>
Acked-By: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This handles the tag added by the PMAC on the VRX200 SoC line.
The GSWIP uses internally a GSWIP special tag which is located after the
Ethernet header. The PMAC which connects the GSWIP to the CPU converts
this special tag used by the GSWIP into the PMAC special tag which is
added in front of the Ethernet header.
This was tested with GSWIP 2.1 found in the VRX200 SoCs, other GSWIP
versions use slightly different PMAC special tags.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for entries which are "sticky", i.e. will not change their port
if they show up from a different one. A new ndm flag is introduced for that
purpose - NTF_STICKY. We allow to set it only to non-local entries.
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Helper bpg_msg_pull_data() can allocate multiple pages while
linearizing multiple scatterlist elements into one shared page.
However, if the shared page has size > PAGE_SIZE, using
copy_page_to_iter() causes below warning.
e.g.
[ 6367.019832] WARNING: CPU: 2 PID: 7410 at lib/iov_iter.c:825
page_copy_sane.part.8+0x0/0x8
To avoid above warning, use __GFP_COMP while allocating multiple
contiguous pages.
Fixes: 015632bb30 ("bpf: sk_msg program helper bpf_sk_msg_pull_data")
Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
When a rds sock is bound, it is inserted into the bind_hash_table
which is protected by RCU. But when releasing rds sock, after it
is removed from this hash table, it is freed immediately without
respecting RCU grace period. This could cause some use-after-free
as reported by syzbot.
Mark the rds sock with SOCK_RCU_FREE before inserting it into the
bind_hash_table, so that it would be always freed after a RCU grace
period.
The other problem is in rds_find_bound(), the rds sock could be
freed in between rhashtable_lookup_fast() and rds_sock_addref(),
so we need to extend RCU read lock protection in rds_find_bound()
to close this race condition.
Reported-and-tested-by: syzbot+8967084bcac563795dc6@syzkaller.appspotmail.com
Reported-by: syzbot+93a5839deb355537440f@syzkaller.appspotmail.com
Cc: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Cc: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Cc: rds-devel@oss.oracle.com
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oarcle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The type of hash::nelems has been changed from size_t to atom_t
which in fact is int, so not need to check if BITS_PER_LONG, that
is bit number of size_t, is bigger than 32
and rht_grow_above_max() will be called to check if hashtable is
too big, ensure it can not bigger than 1<<31
Signed-off-by: Zhang Yu <zhangyu31@baidu.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In tls_sw_sendmsg() and tls_sw_sendpage(), the variable 'ret' has
been set to return value of tls_complete_pending_work(). This allows
return of proper error code if tls_complete_pending_work() fails.
Fixes: 3c4d755915 ("tls: kernel TLS support")
Signed-off-by: Vakul Garg <vakul.garg@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Convert pr_info to net_info_ratelimited to limit the total number of
synflood warnings.
Commit 946cedccbd ("tcp: Change possible SYN flooding messages")
rate limits synflood warnings to one per listener.
Workloads that open many listener sockets can still see a high rate of
log messages. Syzkaller is one frequent example.
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pablo Neira Ayuso says:
====================
Netfilter fixes for net
The following patchset contains Netfilter fixes for you net tree:
1) Remove duplicated include at the end of UDP conntrack, from Yue Haibing.
2) Restore conntrack dependency on xt_cluster, from Martin Willi.
3) Fix splat with GSO skbs from the checksum target, from Florian Westphal.
4) Rework ct timeout support, the template strategy to attach custom timeouts
is not correct since it will not work in conjunction with conntrack zones
and we have a possible free after use when removing the rule due to missing
refcounting. To fix these problems, do not use conntrack template at all
and set custom timeout on the already valid conntrack object. This
fix comes with a preparation patch to simplify timeout adjustment by
initializating the first position of the timeout array for all of the
existing trackers. Patchset from Florian Westphal.
5) Fix missing dependency on from IPv4 chain NAT type, from Florian.
6) Release chain reference counter from the flush path, from Taehee Yoo.
7) After flushing an iptables ruleset, conntrack hooks are unregistered
and entries are left stale to be cleaned up by the timeout garbage
collector. No TCP tracking is done on established flows by this time.
If ruleset is reloaded, then hooks are registered again and TCP
tracking is restored, which considers packets to be invalid. Clear
window tracking to exercise TCP flow pickup from the middle given that
history is lost for us. Again from Florian.
8) Fix crash from netlink interface with CONFIG_NF_CONNTRACK_TIMEOUT=y
and CONFIG_NF_CT_NETLINK_TIMEOUT=n.
9) Broken CT target due to returning incorrect type from
ctnl_timeout_find_get().
10) Solve conntrack clash on NF_REPEAT verdicts too, from Michal Vaner.
11) Missing conversion of hashlimit sysctl interface to new API, from
Cong Wang.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Building with CONFIG_INET=n will show the warning below:
net/core/filter.c: In function ‘____bpf_getsockopt’:
net/core/filter.c:4048:19: warning: unused variable ‘tp’ [-Wunused-variable]
struct tcp_sock *tp;
^~
net/core/filter.c:4046:31: warning: unused variable ‘icsk’ [-Wunused-variable]
struct inet_connection_sock *icsk;
^~~~
Move the variable declarations inside the {} block where they are used.
Fixes: 1e215300f1 ("bpf: add TCP_SAVE_SYN/TCP_SAVED_SYN options for bpf_(set|get)sockopt")
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A remote device may claim that it has received our OOB data, even
though we never geneated it. Add a new flag to track whether we
actually have OOB data, and ignore the remote peer's flag if haven't
generated OOB data.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Since commit 222d7dbd25 ("net: prevent dst uses after free")
skb_dst_force() might clear the dst_entry attached to the skb.
The xfrm code don't expect this to happen, so we crash with
a NULL pointer dereference in this case. Fix it by checking
skb_dst(skb) for NULL after skb_dst_force() and drop the packet
in cast the dst_entry was cleared.
Fixes: 222d7dbd25 ("net: prevent dst uses after free")
Reported-by: Tobias Hommel <netdev-list@genoetigt.de>
Reported-by: Kristian Evensen <kristian.evensen@gmail.com>
Reported-by: Wolfgang Walter <linux@stwm.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
After switching to the new procfs API, it is supposed to
retrieve the private pointer from PDE_DATA(file_inode(s->file)),
s->private is no longer referred.
Fixes: 1cd6718272 ("netfilter/x_tables: switch to proc_create_seq_private")
Reported-by: Sami Farin <hvtaifwkbgefbaei@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Tested-by: Sami Farin <hvtaifwkbgefbaei@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
NF_REPEAT places the packet at the beginning of the iptables chain
instead of accepting or rejecting it right away. The packet however will
reach the end of the chain and continue to the end of iptables
eventually, so it needs the same handling as NF_ACCEPT and NF_DROP.
Fixes: 368982cd7d ("netfilter: nfnetlink_queue: resolve clash for unconfirmed conntracks")
Signed-off-by: Michal 'vorner' Vaner <michal.vaner@avast.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Compiler did not catch incorrect typing in the rcu hook assignment.
% nfct add timeout test-tcp inet tcp established 100 close 10 close_wait 10
% iptables -I OUTPUT -t raw -p tcp -j CT --timeout test-tcp
dmesg - xt_CT: Timeout policy `test-tcp' can only be used by L3 protocol number 25000
The CT target bails out with incorrect layer 3 protocol number.
Fixes: 6c1fd7dc48 ("netfilter: cttimeout: decouple timeout policy from nfnetlink_cttimeout object")
Reported-by: Harsha Sharma <harshasharmaiitr@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Now that cttimeout support for nft_ct is in place, these should depend
on CONFIG_NF_CONNTRACK_TIMEOUT otherwise we can crash when dumping the
policy if this option is not enabled.
[ 71.600121] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[...]
[ 71.600141] CPU: 3 PID: 7612 Comm: nft Not tainted 4.18.0+ #246
[...]
[ 71.600188] Call Trace:
[ 71.600201] ? nft_ct_timeout_obj_dump+0xc6/0xf0 [nft_ct]
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Doug Smythies says:
Sometimes it is desirable to temporarily disable, or clear,
the iptables rule set on a computer being controlled via a
secure shell session (SSH). While unwise on an internet facing
computer, I also do it often on non-internet accessible computers
while testing. Recently, this has become problematic, with the
SSH session being dropped upon re-load of the rule set.
The problem is that when all rules are deleted, conntrack hooks get
unregistered.
In case the rules are re-added later, its possible that tcp window
has moved far enough so that all packets are considered invalid (out of
window) until entry expires (which can take forever, default
established timeout is 5 days).
Fix this by clearing maxwin of existing tcp connections on register.
v2: don't touch entries on hook removal.
v3: remove obsolete expiry check.
Reported-by: Doug Smythies <dsmythies@telus.net>
Fixes: 4d3a57f23d ("netfilter: conntrack: do not enable connection tracking unless needed")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We no longer take any spinlock on RX path for ingress qdisc,
so this lockdep annotation is no longer needed.
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Change flower in_hw_count type to fixed-size u32 and dump it as
TCA_FLOWER_IN_HW_COUNT. This change is necessary to properly test shared
blocks and re-offload functionality.
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It documents what is happening, and eliminates the spurious list
pointer poisoning.
In the long term, in order to get proper list head debugging, we
might want to use the list poison value as the indicator that
an SKB is a singleton and not on a list.
Signed-off-by: David S. Miller <davem@davemloft.net>
An SKB is not on a list if skb->next is NULL.
Codify this convention into a helper function and use it
where we are dequeueing an SKB and need to mark it as such.
Signed-off-by: David S. Miller <davem@davemloft.net>
