Create a new drop reason subsystem for openvswitch and add the first
drop reason to represent last-action drops.
Last-action drops happen when a flow has an empty action list or there
is no action that consumes the packet (output, userspace, recirc, etc).
It is the most common way in which OVS drops packets.
Implementation-wise, most of these skb-consuming actions already call
"consume_skb" internally and return directly from within the
do_execute_actions() loop so with minimal changes we can assume that
any skb that exits the loop normally is a packet drop.
Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It can be really hard to analyse or debug why packets are
going missing in mac80211, so add the needed infrastructure
to use use the new per-subsystem drop reasons.
We actually use two drop reason subsystems here because of
the different handling of frames that are dropped but still
go to monitor for old versions of hostapd, and those that
are just completely unusable (e.g. crypto failed.)
Annotate a few reasons here just to illustrate this, we'll
need to go through and annotate more of them later.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Extend drop reasons to make them usable by subsystems
other than core by reserving the high 16 bits for a
new subsystem ID, of which 0 of course is used for the
existing reasons immediately.
To still be able to have string reasons, restructure
that code a bit to make the loopup under RCU, the only
user of this (right now) is drop_monitor.
Link: https://lore.kernel.org/netdev/00659771ed54353f92027702c5bbb84702da62ce.camel@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This will, after the next patch, hold only the core
drop reasons and minimal infrastructure. Fix a small
kernel-doc issue while at it, to avoid the move
triggering a checker.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Hosts can often receive neighbour discovery messages
that are not for them.
Use a dedicated drop reason to make clear the packet is dropped
for this normal case.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is a generic drop reason for any error detected
in ndisc_parse_options().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Creates three new drop reasons:
SKB_DROP_REASON_IPV6_NDISC_FRAG: invalid frag (suppress_frag_ndisc).
SKB_DROP_REASON_IPV6_NDISC_HOP_LIMIT: invalid hop limit.
SKB_DROP_REASON_IPV6_NDISC_BAD_CODE: invalid NDISC icmp6 code.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This drop reason can be used whenever an IPv6 packet
has a malformed extension header.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
IPv4 reassembly unit can decide to drop frags based on
/proc/sys/net/ipv4/ipfrag_max_dist sysctl.
Add a specific drop reason to track this specific
and weird case.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Used to track skbs freed after a timeout happened
in a reassmbly unit.
Passing a @reason argument to inet_frag_rbtree_purge()
allows to use correct consumed status for frags
that have been successfully re-assembled.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This is used to track when a duplicate segment received by various
reassembly units is dropped.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This will allow to simply use in the future:
kfree_skb_reason(skb, reason);
Instead of repeating sequences like:
if (dropped)
kfree_skb_reason(skb, reason);
else
consume_skb(skb);
For instance, following patch in the series is adding
@reason to skb_release_data() and skb_release_all(),
so that we can propagate a meaningful @reason whenever
consume_skb()/kfree_skb() have to take care of a potential frag_list.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
As Eric reported, the 'reason' field is not presented when trace the
kfree_skb event by perf:
$ perf record -e skb:kfree_skb -a sleep 10
$ perf script
ip_defrag 14605 [021] 221.614303: skb:kfree_skb:
skbaddr=0xffff9d2851242700 protocol=34525 location=0xffffffffa39346b1
reason:
The cause seems to be passing kernel address directly to TP_printk(),
which is not right. As the enum 'skb_drop_reason' is not exported to
user space through TRACE_DEFINE_ENUM(), perf can't get the drop reason
string from the 'reason' field, which is a number.
Therefore, we introduce the macro DEFINE_DROP_REASON(), which is used
to define the trace enum by TRACE_DEFINE_ENUM(). With the help of
DEFINE_DROP_REASON(), now we can remove the auto-generate that we
introduced in the commit ec43908dd5
("net: skb: use auto-generation to convert skb drop reason to string"),
and define the string array 'drop_reasons'.
Hmmmm...now we come back to the situation that have to maintain drop
reasons in both enum skb_drop_reason and DEFINE_DROP_REASON. But they
are both in dropreason.h, which makes it easier.
After this commit, now the format of kfree_skb is like this:
$ cat /tracing/events/skb/kfree_skb/format
name: kfree_skb
ID: 1524
format:
field:unsigned short common_type; offset:0; size:2; signed:0;
field:unsigned char common_flags; offset:2; size:1; signed:0;
field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
field:int common_pid; offset:4; size:4; signed:1;
field:void * skbaddr; offset:8; size:8; signed:0;
field:void * location; offset:16; size:8; signed:0;
field:unsigned short protocol; offset:24; size:2; signed:0;
field:enum skb_drop_reason reason; offset:28; size:4; signed:0;
print fmt: "skbaddr=%p protocol=%u location=%p reason: %s", REC->skbaddr, REC->protocol, REC->location, __print_symbolic(REC->reason, { 1, "NOT_SPECIFIED" }, { 2, "NO_SOCKET" } ......
Fixes: ec43908dd5 ("net: skb: use auto-generation to convert skb drop reason to string")
Link: https://lore.kernel.org/netdev/CANn89i+bx0ybvE55iMYf5GJM48WwV1HNpdm9Q6t-HaEstqpCSA@mail.gmail.com/
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
To make the code clear, reformat the comment in dropreason.h to k-doc
style.
Now, the comment can pass the check of kernel-doc without warnning:
$ ./scripts/kernel-doc -v -none include/linux/dropreason.h
include/linux/dropreason.h:7: info: Scanning doc for enum skb_drop_reason
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
It is annoying to add new skb drop reasons to 'enum skb_drop_reason'
and TRACE_SKB_DROP_REASON in trace/event/skb.h, and it's easy to forget
to add the new reasons we added to TRACE_SKB_DROP_REASON.
TRACE_SKB_DROP_REASON is used to convert drop reason of type number
to string. For now, the string we passed to user space is exactly the
same as the name in 'enum skb_drop_reason' with a 'SKB_DROP_REASON_'
prefix. Therefore, we can use 'auto-generation' to generate these
drop reasons to string at build time.
The new source 'dropreason_str.c' will be auto generated during build
time, which contains the string array
'const char * const drop_reasons[]'.
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
As the skb drop reasons are getting more and more, move the enum
'skb_drop_reason' and related function to the standalone header
'dropreason.h', as Jakub Kicinski suggested.
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
