kernel/linux.git/include/net/rtnetlink.h, branch v6.19.11

rtnetlink: Remove "net" from newlink params

2025-02-21T23:28:03+00:00

Now that devices have been converted to use the specific netns instead of ambiguous "net", let's remove it from newlink parameters. Signed-off-by: Xiao Liang Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250219125039.18024-11-shaw.leon@gmail.com Signed-off-by: Jakub Kicinski

net: Use link/peer netns in newlink() of rtnl_link_ops

2025-02-21T23:28:02+00:00

Add two helper functions - rtnl_newlink_link_net() and rtnl_newlink_peer_net() for netns fallback logic. Peer netns falls back to link netns, and link netns falls back to source netns. Convert the use of params->net in netdevice drivers to one of the helper functions for clarity. Signed-off-by: Xiao Liang Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250219125039.18024-4-shaw.leon@gmail.com Signed-off-by: Jakub Kicinski

rtnetlink: Pack newlink() params into struct

2025-02-21T23:28:02+00:00

There are 4 net namespaces involved when creating links: - source netns - where the netlink socket resides, - target netns - where to put the device being created, - link netns - netns associated with the device (backend), - peer netns - netns of peer device. Currently, two nets are passed to newlink() callback - "src_net" parameter and "dev_net" (implicitly in net_device). They are set as follows, depending on netlink attributes in the request. +------------+-------------------+---------+---------+ | peer netns | IFLA_LINK_NETNSID | src_net | dev_net | +------------+-------------------+---------+---------+ | | absent | source | target | | absent +-------------------+---------+---------+ | | present | link | link | +------------+-------------------+---------+---------+ | | absent | peer | target | | present +-------------------+---------+---------+ | | present | peer | link | +------------+-------------------+---------+---------+ When IFLA_LINK_NETNSID is present, the device is created in link netns first and then moved to target netns. This has some side effects, including extra ifindex allocation, ifname validation and link events. These could be avoided if we create it in target netns from the beginning. On the other hand, the meaning of src_net parameter is ambiguous. It varies depending on how parameters are passed. It is the effective link (or peer netns) by design, but some drivers ignore it and use dev_net instead. To provide more netns context for drivers, this patch packs existing newlink() parameters, along with the source netns, link netns and peer netns, into a struct. The old "src_net" is renamed to "net" to avoid confusion with real source netns, and will be deprecated later. The use of src_net are converted to params->net trivially. Signed-off-by: Xiao Liang Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250219125039.18024-3-shaw.leon@gmail.com Signed-off-by: Jakub Kicinski

rtnetlink: Register rtnl_dellink() and rtnl_setlink() with RTNL_FLAG_DOIT_PERNET_WIP.

2024-11-12T01:26:52+00:00

Currently, rtnl_setlink() and rtnl_dellink() cannot be fully converted to per-netns RTNL due to a lack of handling peer/lower/upper devices in different netns. For example, when we change a device in rtnl_setlink() and need to propagate that to its upper devices, we want to avoid acquiring all netns locks, for which we do not know the upper limit. The same situation happens when we remove a device. rtnl_dellink() could be transformed to remove a single device in the requested netns and delegate other devices to per-netns work, and rtnl_setlink() might be ? Until we come up with a better idea, let's use a new flag RTNL_FLAG_DOIT_PERNET_WIP for rtnl_dellink() and rtnl_setlink(). This will unblock converting RTNL users where such devices are not related. Signed-off-by: Kuniyuki Iwashima Reviewed-by: Nikolay Aleksandrov Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20241108004823.29419-11-kuniyu@amazon.com Signed-off-by: Jakub Kicinski

rtnetlink: Add peer_type in struct rtnl_link_ops.

2024-11-12T01:26:52+00:00

In ops->newlink(), veth, vxcan, and netkit call rtnl_link_get_net() with a net pointer, which is the first argument of ->newlink(). rtnl_link_get_net() could return another netns based on IFLA_NET_NS_PID and IFLA_NET_NS_FD in the peer device's attributes. We want to get it and fill rtnl_nets->nets[] in advance in rtnl_newlink() for per-netns RTNL. All of the three get the peer netns in the same way: 1. Call rtnl_nla_parse_ifinfomsg() 2. Call ops->validate() (vxcan doesn't have) 3. Call rtnl_link_get_net_tb() Let's add a new field peer_type to struct rtnl_link_ops and prefetch netns in the peer ifla to add it to rtnl_nets in rtnl_newlink(). Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20241108004823.29419-6-kuniyu@amazon.com Signed-off-by: Jakub Kicinski

rtnetlink: Remove __rtnl_link_register()

2024-11-12T01:26:51+00:00

link_ops is protected by link_ops_mutex and no longer needs RTNL, so we have no reason to have __rtnl_link_register() separately. Let's remove it and call rtnl_link_register() from ifb.ko and dummy.ko. Note that both modules' init() work on init_net only, so we need not export pernet_ops_rwsem and can use rtnl_net_lock() there. Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20241108004823.29419-4-kuniyu@amazon.com Signed-off-by: Jakub Kicinski

rtnetlink: Protect link_ops by mutex.

2024-11-12T01:26:51+00:00

rtnl_link_unregister() holds RTNL and calls synchronize_srcu(), but rtnl_newlink() will acquire SRCU frist and then RTNL. Then, we need to unlink ops and call synchronize_srcu() outside of RTNL to avoid the deadlock. rtnl_link_unregister() rtnl_newlink() ---- ---- lock(rtnl_mutex); lock(&ops->srcu); lock(rtnl_mutex); sync(&ops->srcu); Let's move as such and add a mutex to protect link_ops. Now, link_ops is protected by its dedicated mutex and rtnl_link_register() no longer needs to hold RTNL. While at it, we move the initialisation of ops->dellink and ops->srcu out of the mutex scope. Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20241108004823.29419-3-kuniyu@amazon.com Signed-off-by: Jakub Kicinski

rtnetlink: Remove __rtnl_link_unregister().

2024-11-12T01:26:51+00:00

rtnl_link_unregister() holds RTNL and calls __rtnl_link_unregister(), where we call synchronize_srcu() to wait inflight RTM_NEWLINK requests for per-netns RTNL. We put synchronize_srcu() in __rtnl_link_unregister() due to ifb.ko and dummy.ko. However, rtnl_newlink() will acquire SRCU before RTNL later in this series. Then, lockdep will detect the deadlock: rtnl_link_unregister() rtnl_newlink() ---- ---- lock(rtnl_mutex); lock(&ops->srcu); lock(rtnl_mutex); sync(&ops->srcu); To avoid the problem, we must call synchronize_srcu() before RTNL in rtnl_link_unregister(). As a preparation, let's remove __rtnl_link_unregister(). Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20241108004823.29419-2-kuniyu@amazon.com Signed-off-by: Jakub Kicinski

rtnetlink: Define RTNL_FLAG_DOIT_PERNET for per-netns RTNL doit().

2024-10-29T10:54:57+00:00

We will push RTNL down to each doit() as rtnl_net_lock(). We can use RTNL_FLAG_DOIT_UNLOCKED to call doit() without RTNL, but doit() will still hold RTNL. Let's define RTNL_FLAG_DOIT_PERNET as an alias of RTNL_FLAG_DOIT_UNLOCKED. Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Signed-off-by: Paolo Abeni

rtnetlink: Protect struct rtnl_af_ops with SRCU.

2024-10-22T09:02:05+00:00

Once RTNL is replaced with rtnl_net_lock(), we need a mechanism to guarantee that rtnl_af_ops is alive during inflight RTM_SETLINK even when its module is being unloaded. Let's use SRCU to protect ops. rtnl_af_lookup() now iterates rtnl_af_ops under RCU and returns SRCU-protected ops pointer. The caller must call rtnl_af_put() to release the pointer after the use. Also, rtnl_af_unregister() unlinks the ops first and calls synchronize_srcu() to wait for inflight RTM_SETLINK requests to complete. Note that rtnl_af_ops needs to be protected by its dedicated lock when RTNL is removed. Note also that BUG_ON() in do_setlink() is changed to the normal error handling as a different af_ops might be found after validate_linkmsg(). Signed-off-by: Kuniyuki Iwashima Signed-off-by: Paolo Abeni