Date: Tue, 02 Apr 2024 14:37:01 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 278130] [netgraph][patch] ng_bridge hooks should auto assign number for [up]link Message-ID: <bug-278130-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D278130 Bug ID: 278130 Summary: [netgraph][patch] ng_bridge hooks should auto assign number for [up]link Product: Base System Version: 14.0-STABLE Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: dave@freedave.net Created attachment 249661 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D249661&action= =3Dedit patches and example ngctl for testing The removal of NG_BRIDGE_MAX_LINKS in review D21803 has made it possible to have way more than 32 connections to an ng_bridge. But there isn't any (eas= y) way for userland to track available link names and requires listing all existing [up]links or to just guess a number until one succeeds. There appears to never be a need to know the link number of the hook on the ng_bridge. When an ng_bridge shuts down it disconnects all hooks. If you kn= ow the path of your ng_eiface, ng_socket, ng_ether, etc. you have a way to `rmhook` without the link path. That is you can remove via either: rmhook <ng_bridge path> [up]linkX or with rmhook <ng_eiface path> ether Everything else that connects to ng_bridge has a similar option. This change, however, is about removing the need to specify an [up]link num= ber when creating a connection to the ng_bridge. Using ng_eiface again it means you can use: connect <ng_eiface path> <ng_bridge path> ether link The ng_bridge will auto assign the lowest available [up]link number that is valid. The number space for [up]link is as large as an int, limited by the fact th= at all netgraph nodes use an int to track the number of connected hooks they h= ave, nd_numhooks in struct ng_node. This turns out to be a convenient fact when introducing unr(9) as I can just initialize to INT_MAX. But it also means y= ou could just take advantage of that and create a numbering scheme in user spa= ce. For example: 0,1 always reserved for ng_ether (which requires 2 hooks) 16 - N reserved for bhyve N - INT_MAX reserved for jails The only issue is that 3rd party scripts would have to agree (e.g. ezjail, vm-bhyve, etc.) Each script would have to scan and when it finds an availab= le [up]link number hope its still there when it attempts the `connect`. "uplink" was introduced with review D23963. I have preserved the requirement you still can not have "uplink0". That will be automatically handled if you connect and request "uplink", it will give you "uplink1" or higher dependin= g on availability but never "uplink0". Because [up]link number is not required it also becomes possible to inspect a netgraph node type and based on that determine the `peerhook` argument to connect to an ng_bridge. I added a change to bhyve to do exactly that. This allows for a simplification when using netgraph with bhyve, which beca= me possible with review D24620. Instead of: -t netgraph,socket=3Dvm0,path=3Dvmbridge:,hook=3Dvm0link,peerhook=3Dlin= k0 You can shorten to just: -t netgraph,path=3Dvmbridge: Instead of: -t netgraph,socket=3Dvm1,path=3Digb0:,hook=3Dvm1link,peerhook=3Dlower You can shorten to just: -t netgraph,path=3Digb0: I'm just removing the need for `peerhook`. No need to specify `socket` or `hook` as the code exists today. Without this you could start just passing "link" = for peerhook when using an ng_bridge. It makes the bhyve change optional, and I= 'm ok if its removed, I mostly care about not having to deal with numbering li= nks for my jails that use ng_eiface. This change is not 100% backward compatible though. The unr(9) is shared by `link` and `uplink`. The current code will allow `link1` and `uplink1` and = this change will not. The total number of [up]links is unchanged. But bear in mi= nd uplink is for a physical interface connected to an ng_bridge, and the expectation is that you have only one of these, so it would be wasteful to = have a separate unr(9) for just "uplink". But other than that it does still allow users to specify [up]link number. The tarball contains patches for CURRENT and stable/14. stable/13 still uses the the array of 32 hooks with NG_BRIDGE_MAX_LINKS. It also contains some simple tests to try with ngctl(8). --=20 You are receiving this mail because: You are the assignee for the bug.=
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