kernel/linux.git/net/ipv6/route.c, branch linux-4.16.y

ipv6: allow PMTU exceptions to local routes

2018-06-25T23:53:53+00:00

[ Upstream commit 0975764684487bf3f7a47eef009e750ea41bd514 ] IPVS setups with local client and remote tunnel server need to create exception for the local virtual IP. What we do is to change PMTU from 64KB (on "lo") to 1460 in the common case. Suggested-by: Martin KaFai Lau Fixes: 45e4fd26683c ("ipv6: Only create RTF_CACHE routes after encountering pmtu exception") Fixes: 7343ff31ebf0 ("ipv6: Don't create clones of host routes.") Signed-off-by: Julian Anastasov Acked-by: David Ahern Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv6: omit traffic class when calculating flow hash

2018-06-11T20:48:15+00:00

[ Upstream commit fa1be7e01ea863e911349e30456706749518eeab ] Some of the code paths calculating flow hash for IPv6 use flowlabel member of struct flowi6 which, despite its name, encodes both flow label and traffic class. If traffic class changes within a TCP connection (as e.g. ssh does), ECMP route can switch between path. It's also inconsistent with other code paths where ip6_flowlabel() (returning only flow label) is used to feed the key. Use only flow label everywhere, including one place where hash key is set using ip6_flowinfo(). Fixes: 51ebd3181572 ("ipv6: add support of equal cost multipath (ECMP)") Fixes: f70ea018da06 ("net: Add functions to get skb->hash based on flow structures") Signed-off-by: Michal Kubecek Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv6: fix uninit-value in ip6_multipath_l3_keys()

2018-05-19T08:19:34+00:00

[ Upstream commit cea67a2dd6b2419dcc13a39309b9a79a1f773193 ] syzbot/KMSAN reported an uninit-value in ip6_multipath_l3_keys(), root caused to a bad assumption of ICMP header being already pulled in skb->head ip_multipath_l3_keys() does the correct thing, so it is an IPv6 only bug. BUG: KMSAN: uninit-value in ip6_multipath_l3_keys net/ipv6/route.c:1830 [inline] BUG: KMSAN: uninit-value in rt6_multipath_hash+0x5c4/0x640 net/ipv6/route.c:1858 CPU: 0 PID: 4507 Comm: syz-executor661 Not tainted 4.16.0+ #87 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683 ip6_multipath_l3_keys net/ipv6/route.c:1830 [inline] rt6_multipath_hash+0x5c4/0x640 net/ipv6/route.c:1858 ip6_route_input+0x65a/0x920 net/ipv6/route.c:1884 ip6_rcv_finish+0x413/0x6e0 net/ipv6/ip6_input.c:69 NF_HOOK include/linux/netfilter.h:288 [inline] ipv6_rcv+0x1e16/0x2340 net/ipv6/ip6_input.c:208 __netif_receive_skb_core+0x47df/0x4a90 net/core/dev.c:4562 __netif_receive_skb net/core/dev.c:4627 [inline] netif_receive_skb_internal+0x49d/0x630 net/core/dev.c:4701 netif_receive_skb+0x230/0x240 net/core/dev.c:4725 tun_rx_batched drivers/net/tun.c:1555 [inline] tun_get_user+0x740f/0x7c60 drivers/net/tun.c:1962 tun_chr_write_iter+0x1d4/0x330 drivers/net/tun.c:1990 call_write_iter include/linux/fs.h:1782 [inline] new_sync_write fs/read_write.c:469 [inline] __vfs_write+0x7fb/0x9f0 fs/read_write.c:482 vfs_write+0x463/0x8d0 fs/read_write.c:544 SYSC_write+0x172/0x360 fs/read_write.c:589 SyS_write+0x55/0x80 fs/read_write.c:581 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 Fixes: 23aebdacb05d ("ipv6: Compute multipath hash for ICMP errors from offending packet") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Jakub Sitnicki Acked-by: Jakub Sitnicki Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv6: add RTA_TABLE and RTA_PREFSRC to rtm_ipv6_policy

2018-04-29T09:35:44+00:00

[ Upstream commit aa8f8778493c85fff480cdf8b349b1e1dcb5f243 ] KMSAN reported use of uninit-value that I tracked to lack of proper size check on RTA_TABLE attribute. I also believe RTA_PREFSRC lacks a similar check. Fixes: 86872cb57925 ("[IPv6] route: FIB6 configuration using struct fib6_config") Fixes: c3968a857a6b ("ipv6: RTA_PREFSRC support for ipv6 route source address selection") Signed-off-by: Eric Dumazet Reported-by: syzbot Acked-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net/ipv6: Fix route leaking between VRFs

2018-03-30T18:23:59+00:00

Donald reported that IPv6 route leaking between VRFs is not working. The root cause is the strict argument in the call to rt6_lookup when validating the nexthop spec. ip6_route_check_nh validates the gateway and device (if given) of a route spec. It in turn could call rt6_lookup (e.g., lookup in a given table did not succeed so it falls back to a full lookup) and if so sets the strict argument to 1. That means if the egress device is given, the route lookup needs to return a result with the same device. This strict requirement does not work with VRFs (IPv4 or IPv6) because the oif in the flow struct is overridden with the index of the VRF device to trigger a match on the l3mdev rule and force the lookup to its table. The right long term solution is to add an l3mdev index to the flow struct such that the oif is not overridden. That solution will not backport well, so this patch aims for a simpler solution to relax the strict argument if the route spec device is an l3mdev slave. As done in other places, use the FLOWI_FLAG_SKIP_NH_OIF to know that the RT6_LOOKUP_F_IFACE flag needs to be removed. Fixes: ca254490c8df ("net: Add VRF support to IPv6 stack") Reported-by: Donald Sharp Signed-off-by: David Ahern Signed-off-by: David S. Miller

ipv6: fix possible deadlock in rt6_age_examine_exception()

2018-03-23T17:40:34+00:00

syzbot reported a LOCKDEP splat [1] in rt6_age_examine_exception() rt6_age_examine_exception() is called while rt6_exception_lock is held. This lock is the lower one in the lock hierarchy, thus we can not call dst_neigh_lookup() function, as it can fallback to neigh_create() We should instead do a pure RCU lookup. As a bonus we avoid a pair of atomic operations on neigh refcount. [1] WARNING: possible circular locking dependency detected 4.16.0-rc4+ #277 Not tainted syz-executor7/4015 is trying to acquire lock: (&ndev->lock){++--}, at: [<00000000416dce19>] __ipv6_dev_mc_dec+0x45/0x350 net/ipv6/mcast.c:928 but task is already holding lock: (&tbl->lock){++-.}, at: [<00000000b5cb1d65>] neigh_ifdown+0x3d/0x250 net/core/neighbour.c:292 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&tbl->lock){++-.}: __raw_write_lock_bh include/linux/rwlock_api_smp.h:203 [inline] _raw_write_lock_bh+0x31/0x40 kernel/locking/spinlock.c:312 __neigh_create+0x87e/0x1d90 net/core/neighbour.c:528 neigh_create include/net/neighbour.h:315 [inline] ip6_neigh_lookup+0x9a7/0xba0 net/ipv6/route.c:228 dst_neigh_lookup include/net/dst.h:405 [inline] rt6_age_examine_exception net/ipv6/route.c:1609 [inline] rt6_age_exceptions+0x381/0x660 net/ipv6/route.c:1645 fib6_age+0xfb/0x140 net/ipv6/ip6_fib.c:2033 fib6_clean_node+0x389/0x580 net/ipv6/ip6_fib.c:1919 fib6_walk_continue+0x46c/0x8a0 net/ipv6/ip6_fib.c:1845 fib6_walk+0x91/0xf0 net/ipv6/ip6_fib.c:1893 fib6_clean_tree+0x1e6/0x340 net/ipv6/ip6_fib.c:1970 __fib6_clean_all+0x1f4/0x3a0 net/ipv6/ip6_fib.c:1986 fib6_clean_all net/ipv6/ip6_fib.c:1997 [inline] fib6_run_gc+0x16b/0x3c0 net/ipv6/ip6_fib.c:2053 ndisc_netdev_event+0x3c2/0x4a0 net/ipv6/ndisc.c:1781 notifier_call_chain+0x136/0x2c0 kernel/notifier.c:93 __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401 call_netdevice_notifiers_info+0x32/0x70 net/core/dev.c:1707 call_netdevice_notifiers net/core/dev.c:1725 [inline] __dev_notify_flags+0x262/0x430 net/core/dev.c:6960 dev_change_flags+0xf5/0x140 net/core/dev.c:6994 devinet_ioctl+0x126a/0x1ac0 net/ipv4/devinet.c:1080 inet_ioctl+0x184/0x310 net/ipv4/af_inet.c:919 sock_do_ioctl+0xef/0x390 net/socket.c:957 sock_ioctl+0x36b/0x610 net/socket.c:1081 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #2 (rt6_exception_lock){+.-.}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168 spin_lock_bh include/linux/spinlock.h:315 [inline] rt6_flush_exceptions+0x21/0x210 net/ipv6/route.c:1367 fib6_del_route net/ipv6/ip6_fib.c:1677 [inline] fib6_del+0x624/0x12c0 net/ipv6/ip6_fib.c:1761 __ip6_del_rt+0xc7/0x120 net/ipv6/route.c:2980 ip6_del_rt+0x132/0x1a0 net/ipv6/route.c:2993 __ipv6_dev_ac_dec+0x3b1/0x600 net/ipv6/anycast.c:332 ipv6_dev_ac_dec net/ipv6/anycast.c:345 [inline] ipv6_sock_ac_close+0x2b4/0x3e0 net/ipv6/anycast.c:200 inet6_release+0x48/0x70 net/ipv6/af_inet6.c:433 sock_release+0x8d/0x1e0 net/socket.c:594 sock_close+0x16/0x20 net/socket.c:1149 __fput+0x327/0x7e0 fs/file_table.c:209 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x199/0x270 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x9bb/0x1ad0 kernel/exit.c:865 do_group_exit+0x149/0x400 kernel/exit.c:968 get_signal+0x73a/0x16d0 kernel/signal.c:2469 do_signal+0x90/0x1e90 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:265 [inline] do_syscall_64+0x6ec/0x940 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #1 (&(&tb->tb6_lock)->rlock){+.-.}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168 spin_lock_bh include/linux/spinlock.h:315 [inline] __ip6_ins_rt+0x56/0x90 net/ipv6/route.c:1007 ip6_route_add+0x141/0x190 net/ipv6/route.c:2955 addrconf_prefix_route+0x44f/0x620 net/ipv6/addrconf.c:2359 fixup_permanent_addr net/ipv6/addrconf.c:3368 [inline] addrconf_permanent_addr net/ipv6/addrconf.c:3391 [inline] addrconf_notify+0x1ad2/0x2310 net/ipv6/addrconf.c:3460 notifier_call_chain+0x136/0x2c0 kernel/notifier.c:93 __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401 call_netdevice_notifiers_info+0x32/0x70 net/core/dev.c:1707 call_netdevice_notifiers net/core/dev.c:1725 [inline] __dev_notify_flags+0x15d/0x430 net/core/dev.c:6958 dev_change_flags+0xf5/0x140 net/core/dev.c:6994 do_setlink+0xa22/0x3bb0 net/core/rtnetlink.c:2357 rtnl_newlink+0xf37/0x1a50 net/core/rtnetlink.c:2965 rtnetlink_rcv_msg+0x57f/0xb10 net/core/rtnetlink.c:4641 netlink_rcv_skb+0x14b/0x380 net/netlink/af_netlink.c:2444 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4659 netlink_unicast_kernel net/netlink/af_netlink.c:1308 [inline] netlink_unicast+0x4c4/0x6b0 net/netlink/af_netlink.c:1334 netlink_sendmsg+0xa4a/0xe60 net/netlink/af_netlink.c:1897 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xca/0x110 net/socket.c:639 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2047 __sys_sendmsg+0xe5/0x210 net/socket.c:2081 SYSC_sendmsg net/socket.c:2092 [inline] SyS_sendmsg+0x2d/0x50 net/socket.c:2088 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #0 (&ndev->lock){++--}: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920 __raw_write_lock_bh include/linux/rwlock_api_smp.h:203 [inline] _raw_write_lock_bh+0x31/0x40 kernel/locking/spinlock.c:312 __ipv6_dev_mc_dec+0x45/0x350 net/ipv6/mcast.c:928 ipv6_dev_mc_dec+0x110/0x1f0 net/ipv6/mcast.c:961 pndisc_destructor+0x21a/0x340 net/ipv6/ndisc.c:392 pneigh_ifdown net/core/neighbour.c:695 [inline] neigh_ifdown+0x149/0x250 net/core/neighbour.c:294 rt6_disable_ip+0x537/0x700 net/ipv6/route.c:3874 addrconf_ifdown+0x14b/0x14f0 net/ipv6/addrconf.c:3633 addrconf_notify+0x5f8/0x2310 net/ipv6/addrconf.c:3557 notifier_call_chain+0x136/0x2c0 kernel/notifier.c:93 __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401 call_netdevice_notifiers_info+0x32/0x70 net/core/dev.c:1707 call_netdevice_notifiers net/core/dev.c:1725 [inline] __dev_notify_flags+0x262/0x430 net/core/dev.c:6960 dev_change_flags+0xf5/0x140 net/core/dev.c:6994 devinet_ioctl+0x126a/0x1ac0 net/ipv4/devinet.c:1080 inet_ioctl+0x184/0x310 net/ipv4/af_inet.c:919 packet_ioctl+0x1ff/0x310 net/packet/af_packet.c:4066 sock_do_ioctl+0xef/0x390 net/socket.c:957 sock_ioctl+0x36b/0x610 net/socket.c:1081 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 other info that might help us debug this: Chain exists of: &ndev->lock --> rt6_exception_lock --> &tbl->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&tbl->lock); lock(rt6_exception_lock); lock(&tbl->lock); lock(&ndev->lock); *** DEADLOCK *** 2 locks held by syz-executor7/4015: #0: (rtnl_mutex){+.+.}, at: [<00000000a2f16daa>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 #1: (&tbl->lock){++-.}, at: [<00000000b5cb1d65>] neigh_ifdown+0x3d/0x250 net/core/neighbour.c:292 stack backtrace: CPU: 0 PID: 4015 Comm: syz-executor7 Not tainted 4.16.0-rc4+ #277 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 print_circular_bug.isra.38+0x2cd/0x2dc kernel/locking/lockdep.c:1223 check_prev_add kernel/locking/lockdep.c:1863 [inline] check_prevs_add kernel/locking/lockdep.c:1976 [inline] validate_chain kernel/locking/lockdep.c:2417 [inline] __lock_acquire+0x30a8/0x3e00 kernel/locking/lockdep.c:3431 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920 __raw_write_lock_bh include/linux/rwlock_api_smp.h:203 [inline] _raw_write_lock_bh+0x31/0x40 kernel/locking/spinlock.c:312 __ipv6_dev_mc_dec+0x45/0x350 net/ipv6/mcast.c:928 ipv6_dev_mc_dec+0x110/0x1f0 net/ipv6/mcast.c:961 pndisc_destructor+0x21a/0x340 net/ipv6/ndisc.c:392 pneigh_ifdown net/core/neighbour.c:695 [inline] neigh_ifdown+0x149/0x250 net/core/neighbour.c:294 rt6_disable_ip+0x537/0x700 net/ipv6/route.c:3874 addrconf_ifdown+0x14b/0x14f0 net/ipv6/addrconf.c:3633 addrconf_notify+0x5f8/0x2310 net/ipv6/addrconf.c:3557 notifier_call_chain+0x136/0x2c0 kernel/notifier.c:93 __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401 call_netdevice_notifiers_info+0x32/0x70 net/core/dev.c:1707 call_netdevice_notifiers net/core/dev.c:1725 [inline] __dev_notify_flags+0x262/0x430 net/core/dev.c:6960 dev_change_flags+0xf5/0x140 net/core/dev.c:6994 devinet_ioctl+0x126a/0x1ac0 net/ipv4/devinet.c:1080 inet_ioctl+0x184/0x310 net/ipv4/af_inet.c:919 packet_ioctl+0x1ff/0x310 net/packet/af_packet.c:4066 sock_do_ioctl+0xef/0x390 net/socket.c:957 sock_ioctl+0x36b/0x610 net/socket.c:1081 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Fixes: c757faa8bfa2 ("ipv6: prepare fib6_age() for exception table") Signed-off-by: Eric Dumazet Cc: Wei Wang Cc: Martin KaFai Lau Acked-by: Wei Wang Signed-off-by: David S. Miller

net/ipv6: Handle onlink flag with multipath routes

2018-03-22T16:40:04+00:00

For multipath routes the ONLINK flag can be specified per nexthop in rtnh_flags or globally in rtm_flags. Update ip6_route_multipath_add to consider the ONLINK setting coming from rtnh_flags. Each loop over nexthops the config for the sibling route is initialized to the global config and then per nexthop settings overlayed. The flag is 'or'ed into fib6_config to handle the ONLINK flag coming from either rtm_flags or rtnh_flags. Fixes: fc1e64e1092f ("net/ipv6: Add support for onlink flag") Signed-off-by: David Ahern Signed-off-by: David S. Miller

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec

2018-03-13T14:38:07+00:00

Steffen Klassert says: ==================== pull request (net): ipsec 2018-03-13 1) Refuse to insert 32 bit userspace socket policies on 64 bit systems like we do it for standard policies. We don't have a compat layer, so inserting socket policies from 32 bit userspace will lead to a broken configuration. 2) Make the policy hold queue work without the flowcache. Dummy bundles are not chached anymore, so we need to generate a new one on each lookup as long as the SAs are not yet in place. 3) Fix the validation of the esn replay attribute. The The sanity check in verify_replay() is bypassed if the XFRM_STATE_ESN flag is not set. Fix this by doing the sanity check uncoditionally. From Florian Westphal. 4) After most of the dst_entry garbage collection code is removed, we may leak xfrm_dst entries as they are neither cached nor tracked somewhere. Fix this by reusing the 'uncached_list' to track xfrm_dst entries too. From Xin Long. 5) Fix a rcu_read_lock/rcu_read_unlock imbalance in xfrm_get_tos() From Xin Long. 6) Fix an infinite loop in xfrm_get_dst_nexthop. On transport mode we fetch the child dst_entry after we continue, so this pointer is never updated. Fix this by fetching it before we continue. 7) Fix ESN sequence number gap after IPsec GSO packets. We accidentally increment the sequence number counter on the xfrm_state by one packet too much in the ESN case. Fix this by setting the sequence number to the correct value. 8) Reset the ethernet protocol after decapsulation only if a mac header was set. Otherwise it breaks configurations with TUN devices. From Yossi Kuperman. 9) Fix __this_cpu_read() usage in preemptible code. Use this_cpu_read() instead in ipcomp_alloc_tfms(). From Greg Hackmann. Please pull or let me know if there are problems. ==================== Signed-off-by: David S. Miller

ipv6: Reflect MTU changes on PMTU of exceptions for MTU-less routes

2018-03-07T18:17:50+00:00

Currently, administrative MTU changes on a given netdevice are not reflected on route exceptions for MTU-less routes, with a set PMTU value, for that device: # ip -6 route get 2001:db8::b 2001:db8::b from :: dev vti_a proto kernel src 2001:db8::a metric 256 pref medium # ping6 -c 1 -q -s10000 2001:db8::b > /dev/null # ip netns exec a ip -6 route get 2001:db8::b 2001:db8::b from :: dev vti_a src 2001:db8::a metric 0 cache expires 571sec mtu 4926 pref medium # ip link set dev vti_a mtu 3000 # ip -6 route get 2001:db8::b 2001:db8::b from :: dev vti_a src 2001:db8::a metric 0 cache expires 571sec mtu 4926 pref medium # ip link set dev vti_a mtu 9000 # ip -6 route get 2001:db8::b 2001:db8::b from :: dev vti_a src 2001:db8::a metric 0 cache expires 571sec mtu 4926 pref medium The first issue is that since commit fb56be83e43d ("net-ipv6: on device mtu change do not add mtu to mtu-less routes") we don't call rt6_exceptions_update_pmtu() from rt6_mtu_change_route(), which handles administrative MTU changes, if the regular route is MTU-less. However, PMTU exceptions should be always updated, as long as RTAX_MTU is not locked. Keep the check for MTU-less main route, as introduced by that commit, but, for exceptions, call rt6_exceptions_update_pmtu() regardless of that check. Once that is fixed, one problem remains: MTU changes are not reflected if the new MTU is higher than the previous one, because rt6_exceptions_update_pmtu() doesn't allow that. We should instead allow PMTU increase if the old PMTU matches the local MTU, as that implies that the old MTU was the lowest in the path, and PMTU discovery might lead to different results. The existing check in rt6_mtu_change_route() correctly took that case into account (for regular routes only), so factor it out and re-use it also in rt6_exceptions_update_pmtu(). While at it, fix comments style and grammar, and try to be a bit more descriptive. Reported-by: Xiumei Mu Fixes: fb56be83e43d ("net-ipv6: on device mtu change do not add mtu to mtu-less routes") Fixes: f5bbe7ee79c2 ("ipv6: prepare rt6_mtu_change() for exception table") Signed-off-by: Stefano Brivio Acked-by: David Ahern Signed-off-by: David S. Miller

xfrm: reuse uncached_list to track xdsts

2018-02-16T06:03:33+00:00

In early time, when freeing a xdst, it would be inserted into dst_garbage.list first. Then if it's refcnt was still held somewhere, later it would be put into dst_busy_list in dst_gc_task(). When one dev was being unregistered, the dev of these dsts in dst_busy_list would be set with loopback_dev and put this dev. So that this dev's removal wouldn't get blocked, and avoid the kmsg warning: kernel:unregister_netdevice: waiting for veth0 to become \ free. Usage count = 2 However after Commit 52df157f17e5 ("xfrm: take refcnt of dst when creating struct xfrm_dst bundle"), the xdst will not be freed with dst gc, and this warning happens. To fix it, we need to find these xdsts that are still held by others when removing the dev, and free xdst's dev and set it with loopback_dev. But unfortunately after flow_cache for xfrm was deleted, no list tracks them anymore. So we need to save these xdsts somewhere to release the xdst's dev later. To make this easier, this patch is to reuse uncached_list to track xdsts, so that the dev refcnt can be released in the event NETDEV_UNREGISTER process of fib_netdev_notifier. Thanks to Florian, we could move forward this fix quickly. Fixes: 52df157f17e5 ("xfrm: take refcnt of dst when creating struct xfrm_dst bundle") Reported-by: Jianlin Shi Reported-by: Hangbin Liu Tested-by: Eyal Birger Signed-off-by: Xin Long Signed-off-by: Steffen Klassert