Add skb drop reasons to the route_req() in struct tcp_request_sock_ops.
Following functions are involved:
tcp_v4_route_req()
tcp_v6_route_req()
subflow_v4_route_req()
subflow_v6_route_req()
And the new reason SKB_DROP_REASON_LSM is added, which is used when
skb is dropped by LSM.
Reviewed-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Hao Peng <flyingpeng@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
In order to get the reasons of skb drops, add a function argument of
type 'enum skb_drop_reason *reason' to tcp_timewait_state_process().
In the origin code, all packets to time-wait socket are treated as
dropping with kfree_skb(), which can make users confused. Therefore,
we use consume_skb() for the skbs that are 'good'. We can check the
value of 'reason' to decide use kfree_skb() or consume_skb().
The new reason 'TIMEWAIT' is added for the case that the skb is dropped
as the socket in time-wait state.
Reviewed-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Hao Peng <flyingpeng@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reported-by: Eric Dumazet <edumazet@google.com>
In order to get skb drop reasons during tcp connect requesting code path,
we have to pass the pointer of the 'reason' as a new function argument of
conn_request() in 'struct inet_connection_sock_af_ops'. As the return
value of conn_request() can be positive or negative or 0, it's not
flexible to make it return drop reasons.
As the return value of tcp_conn_request() is 0, so we can treat it as bool
and make it return the skb drop reasons.
The new drop reasons 'LISTENOVERFLOWS' and 'TCP_REQQFULLDROP' are added,
which are used for 'accept queue' and 'request queue' full.
Reviewed-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Hao Peng <flyingpeng@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reported-by: kernel test robot <lkp@intel.com>
--
v2:
- fix compile error reported by kernel test rebot
For now, the return value of tcp_rcv_state_process() is treated as bool.
Therefore, we can make it return the reasons of the skb drops.
Meanwhile, the return value of tcp_child_process() comes from
tcp_rcv_state_process(), make it drop reasons by the way.
The new drop reason SKB_DROP_REASON_TCP_LINGER is added for skb dropping
out of TCP linger.
Reviewed-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Hao Peng <flyingpeng@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
v3:
- instead SKB_DROP_REASON_TCP_ABORTONDATA with SKB_DROP_REASON_TCP_LINGER
The return value of tcp_rcv_synsent_state_process() can be -1, 0 or 1:
- -1: free skb silently
- 0: success and skb is already freed
- 1: drop packet and send a RST
Therefore, we can make it return skb drop reasons instead of '1' on
'reset_and_undo' path, which will not impact the caller.
The new reason 'TCP_PAWSACTIVEREJECTED' is added, which is corresponding
to LINUX_MIB_PAWSACTIVEREJECTED.
Reviewed-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Hao Peng <flyingpeng@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
skb dropping in inet_csk_destroy_sock() seems to be a common case. Add
the new drop reason 'SKB_DROP_REASON_SOCKET_DESTROIED' and apply it to
inet_csk_destroy_sock() to stop confusing users with 'NOT_SPECIFIED'.
Reviewed-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Hao Peng <flyingpeng@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
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>
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>
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>
Menglong Dong