kernel/linux.git/include/net/if_inet6.h, branch v5.15.89

ipv6: fix locking issues with loops over idev->addr_list

2022-06-09T08:22:31+00:00

[ Upstream commit 51454ea42c1ab4e0c2828bb0d4d53957976980de ] idev->addr_list needs to be protected by idev->lock. However, it is not always possible to do so while iterating and performing actions on inet6_ifaddr instances. For example, multiple functions (like addrconf_{join,leave}_anycast) eventually call down to other functions that acquire the idev->lock. The current code temporarily unlocked the idev->lock during the loops, which can cause race conditions. Moving the locks up is also not an appropriate solution as the ordering of lock acquisition will be inconsistent with for example mc_lock. This solution adds an additional field to inet6_ifaddr that is used to temporarily add the instances to a temporary list while holding idev->lock. The temporary list can then be traversed without holding idev->lock. This change was done in two places. In addrconf_ifdown, the list_for_each_entry_safe variant of the list loop is also no longer necessary as there is no deletion within that specific loop. Suggested-by: Paolo Abeni Signed-off-by: Niels Dossche Acked-by: Paolo Abeni Link: https://lore.kernel.org/r/20220403231523.45843-1-dossche.niels@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ipv6: add IFLA_INET6_RA_MTU to expose mtu value

2021-08-28T00:29:18+00:00

The kernel provides a "/proc/sys/net/ipv6/conf//mtu" file, which can temporarily record the mtu value of the last received RA message when the RA mtu value is lower than the interface mtu, but this proc has following limitations: (1) when the interface mtu (/sys/class/net//mtu) is updeated, mtu6 (/proc/sys/net/ipv6/conf//mtu) will be updated to the value of interface mtu; (2) mtu6 (/proc/sys/net/ipv6/conf//mtu) only affect ipv6 connection, and not affect ipv4. Therefore, when the mtu option is carried in the RA message, there will be a problem that the user sometimes cannot obtain RA mtu value correctly by reading mtu6. After this patch set, if a RA message carries the mtu option, you can send a netlink msg which nlmsg_type is RTM_GETLINK, and then by parsing the attribute of IFLA_INET6_RA_MTU to get the mtu value carried in the RA message received on the inet6 device. In addition, you can also get a link notification when ra_mtu is updated so it doesn't have to poll. In this way, if the MTU values that the device receives from the network in the PCO IPv4 and the RA IPv6 procedures are different, the user can obtain the correct ipv6 ra_mtu value and compare the value of ra_mtu and ipv4 mtu, then the device can use the lower MTU value for both IPv4 and IPv6. Signed-off-by: Rocco Yue Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20210827150412.9267-1-rocco.yue@mediatek.com Signed-off-by: Jakub Kicinski

net/ipv6/mcast: Use struct_size() helper

2021-08-05T10:46:42+00:00

Replace IP6_SFLSIZE() with struct_size() helper in order to avoid any potential type mistakes or integer overflows that, in the worst scenario, could lead to heap overflows. Signed-off-by: Gustavo A. R. Silva Signed-off-by: David S. Miller

mld: add mc_lock for protecting per-interface mld data

2021-03-26T22:14:56+00:00

The purpose of this lock is to avoid a bottleneck in the query/report event handler logic. By previous patches, almost all mld data is protected by RTNL. So, the query and report event handler, which is data path logic acquires RTNL too. Therefore if a lot of query and report events are received, it uses RTNL for a long time. So it makes the control-plane bottleneck because of using RTNL. In order to avoid this bottleneck, mc_lock is added. mc_lock protect only per-interface mld data and per-interface mld data is used in the query/report event handler logic. So, no longer rtnl_lock is needed in the query/report event handler logic. Therefore bottleneck will be disappeared by mc_lock. Suggested-by: Cong Wang Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller

mld: add new workqueues for process mld events

2021-03-26T22:14:56+00:00

When query/report packets are received, mld module processes them. But they are processed under BH context so it couldn't use sleepable functions. So, in order to switch context, the two workqueues are added which processes query and report event. In the struct inet6_dev, mc_{query | report}_queue are added so it is per-interface queue. And mc_{query | report}_work are workqueue structure. When the query or report event is received, skb is queued to proper queue and worker function is scheduled immediately. Workqueues and queues are protected by spinlock, which is mc_{query | report}_lock, and worker functions are protected by RTNL. Suggested-by: Cong Wang Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller

mld: convert ifmcaddr6 to RCU

2021-03-26T22:14:56+00:00

The ifmcaddr6 has been protected by inet6_dev->lock(rwlock) so that the critical section is atomic context. In order to switch this context, changing locking is needed. The ifmcaddr6 actually already protected by RTNL So if it's converted to use RCU, its control path context can be switched to sleepable. Suggested-by: Cong Wang Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller

mld: convert ip6_sf_list to RCU

2021-03-26T22:14:56+00:00

The ip6_sf_list has been protected by mca_lock(spin_lock) so that the critical section is atomic context. In order to switch this context, changing locking is needed. The ip6_sf_list actually already protected by RTNL So if it's converted to use RCU, its control path context can be switched to sleepable. But It doesn't remove mca_lock yet because ifmcaddr6 isn't converted to RCU yet. So, It's not fully converted to the sleepable context. Suggested-by: Cong Wang Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller

mld: convert ipv6_mc_socklist->sflist to RCU

2021-03-26T22:14:56+00:00

The sflist has been protected by rwlock so that the critical section is atomic context. In order to switch this context, changing locking is needed. The sflist actually already protected by RTNL So if it's converted to use RCU, its control path context can be switched to sleepable. Suggested-by: Cong Wang Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller

mld: get rid of inet6_dev->mc_lock

2021-03-26T22:14:55+00:00

The purpose of mc_lock is to protect inet6_dev->mc_tomb. But mc_tomb is already protected by RTNL and all functions, which manipulate mc_tomb are called under RTNL. So, mc_lock is not needed. Furthermore, it is spinlock so the critical section is atomic. In order to reduce atomic context, it should be removed. Suggested-by: Cong Wang Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller

mld: convert from timer to delayed work

2021-03-26T22:14:55+00:00

mcast.c has several timers for delaying works. Timer's expire handler is working under atomic context so it can't use sleepable things such as GFP_KERNEL, mutex, etc. In order to use sleepable APIs, it converts from timers to delayed work. But there are some critical sections, which is used by both process and BH context. So that it still uses spin_lock_bh() and rwlock. Suggested-by: Cong Wang Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller