linux/net/core
Cong Wang 856c395cfa net: introduce a knob to control whether to inherit devconf config
There have been many people complaining about the inconsistent
behaviors of IPv4 and IPv6 devconf when creating new network
namespaces.  Currently, for IPv4, we inherit all current settings
from init_net, but for IPv6 we reset all setting to default.

This patch introduces a new /proc file
/proc/sys/net/core/devconf_inherit_init_net to control the
behavior of whether to inhert sysctl current settings from init_net.
This file itself is only available in init_net.

As demonstrated below:

Initial setup in init_net:
 # cat /proc/sys/net/ipv4/conf/all/rp_filter
 2
 # cat /proc/sys/net/ipv6/conf/all/accept_dad
 1

Default value 0 (current behavior):
 # ip netns del test
 # ip netns add test
 # ip netns exec test cat /proc/sys/net/ipv4/conf/all/rp_filter
 2
 # ip netns exec test cat /proc/sys/net/ipv6/conf/all/accept_dad
 0

Set to 1 (inherit from init_net):
 # echo 1 > /proc/sys/net/core/devconf_inherit_init_net
 # ip netns del test
 # ip netns add test
 # ip netns exec test cat /proc/sys/net/ipv4/conf/all/rp_filter
 2
 # ip netns exec test cat /proc/sys/net/ipv6/conf/all/accept_dad
 1

Set to 2 (reset to default):
 # echo 2 > /proc/sys/net/core/devconf_inherit_init_net
 # ip netns del test
 # ip netns add test
 # ip netns exec test cat /proc/sys/net/ipv4/conf/all/rp_filter
 0
 # ip netns exec test cat /proc/sys/net/ipv6/conf/all/accept_dad
 0

Set to a value out of range (invalid):
 # echo 3 > /proc/sys/net/core/devconf_inherit_init_net
 -bash: echo: write error: Invalid argument
 # echo -1 > /proc/sys/net/core/devconf_inherit_init_net
 -bash: echo: write error: Invalid argument

Reported-by: Zhu Yanjun <Yanjun.Zhu@windriver.com>
Reported-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-22 11:07:21 -08:00
..
datagram.c for-4.21/block-20181221 2018-12-28 13:19:59 -08:00
dev_addr_lists.c net: dev: Issue NETDEV_PRE_CHANGEADDR 2018-12-13 18:41:38 -08:00
dev_ioctl.c net: dev: Add extack argument to dev_set_mac_address() 2018-12-13 18:41:38 -08:00
dev.c jump_label: move 'asm goto' support test to Kconfig 2019-01-06 09:46:51 +09:00
devlink.c devlink: Add health dump {get,clear} commands 2019-01-18 14:51:23 -08:00
drop_monitor.c treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
dst_cache.c net: core: dst_cache_set_ip6: Rename 'addr' parameter to 'saddr' for consistency 2018-03-05 12:52:45 -05:00
dst.c net: add a route cache full diagnostic message 2019-01-17 15:37:25 -08:00
ethtool.c ethtool: check the return value of get_regs_len 2018-12-28 21:24:56 -08:00
failover.c net: Introduce generic failover module 2018-05-28 22:59:54 -04:00
fib_notifier.c net: Fix fib notifer to return errno 2018-03-29 14:10:30 -04:00
fib_rules.c net/fib_rules: Update fib_nl_dumprule for strict data checking 2018-10-08 10:39:05 -07:00
filter.c bpf: in __bpf_redirect_no_mac pull mac only if present 2019-01-20 01:11:48 +01:00
flow_dissector.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-12-20 11:53:36 -08:00
gen_estimator.c net: core: protect rate estimator statistics pointer with lock 2018-08-11 12:37:10 -07:00
gen_stats.c net/core: make function ___gnet_stats_copy_basic() static 2018-09-28 10:25:11 -07:00
gro_cells.c gro_cell: add napi_disable in gro_cells_destroy 2018-12-19 15:50:02 -08:00
hwbm.c
link_watch.c net: linkwatch: add check for netdevice being present to linkwatch_do_dev 2018-09-19 21:06:46 -07:00
lwt_bpf.c bpf: in __bpf_redirect_no_mac pull mac only if present 2019-01-20 01:11:48 +01:00
lwtunnel.c
Makefile bpf, sockmap: convert to generic sk_msg interface 2018-10-15 12:23:19 -07:00
neighbour.c neighbour: Do not perturb drop profiles when neigh_probe 2019-01-17 22:08:14 -08:00
net_namespace.c net: namespace: perform strict checks also for doit handlers 2019-01-19 10:09:58 -08:00
net-procfs.c proc: introduce proc_create_net{,_data} 2018-05-16 07:24:30 +02:00
net-sysfs.c net: core: dev: Add extack argument to dev_change_flags() 2018-12-06 13:26:07 -08:00
net-sysfs.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
net-traces.c net/ipv6: Udate fib6_table_lookup tracepoint 2018-05-24 23:01:15 -04:00
netclassid_cgroup.c cgroup, netclassid: add a preemption point to write_classid 2018-10-23 12:58:17 -07:00
netevent.c
netpoll.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-12-27 13:04:52 -08:00
netprio_cgroup.c net: remove duplicate includes 2017-12-13 13:18:46 -05:00
page_pool.c net/page_pool: Fix inconsistent lock state warning 2018-07-19 23:23:01 -07:00
pktgen.c pktgen: Fix fall-through annotation 2018-09-13 15:36:41 -07:00
ptp_classifier.c
request_sock.c
rtnetlink.c rtnetlink: ifinfo: perform strict checks also for doit handler 2019-01-19 10:09:58 -08:00
scm.c
secure_seq.c infiniband: i40iw, nes: don't use wall time for TCP sequence numbers 2018-07-11 12:10:19 -06:00
skbuff.c net, skbuff: do not prefer skb allocation fails early 2019-01-04 12:53:16 -08:00
skmsg.c Optimize sk_msg_clone() by data merge to end dst sg entry 2019-01-17 11:42:26 -08:00
sock_diag.c net: sock_diag: Fix spectre v1 gadget in __sock_diag_cmd() 2018-08-14 10:01:24 -07:00
sock_map.c bpf: skmsg, fix psock create on existing kcm/tls port 2018-10-20 00:40:45 +02:00
sock_reuseport.c sctp: add sock_reuseport for the sock in __sctp_hash_endpoint 2018-11-12 09:09:51 -08:00
sock.c net: sock: do not set sk_cookie in sk_clone_lock() 2019-01-19 10:34:59 -08:00
stream.c tcp: reduce POLLOUT events caused by TCP_NOTSENT_LOWAT 2018-12-04 21:21:18 -08:00
sysctl_net_core.c net: introduce a knob to control whether to inherit devconf config 2019-01-22 11:07:21 -08:00
timestamping.c
tso.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
utils.c net: Remove some unneeded semicolon 2018-08-04 13:05:39 -07:00
xdp.c xdp: remove redundant variable 'headroom' 2018-09-01 01:35:53 +02:00