superseded: [PATCH proxmox-ebpf v5 0/5] add proxmox-ebpf library

[Hannes Laimer <h.laimer@proxmox.com>]

superseded-by:
https://lore.proxmox.com/pve-devel/20261104134905.1623451-1-h.laimer@proxmox.com/

On 2026-11-02 16:09, Hannes Laimer wrote:
> proxmox-ebpf holds the eBPF programs and the code that loads, attaches
> and updates them, grouped into subsystems. It is a library only, whoever
> needs a subsystem pulls in just that one through a cargo feature and
> calls it from their side. This series is the shared part, the actual
> subsystems come as their own series on top.
> 
> The core is the shared subsystem code. It takes care of everything from
> loading and attaching per interface to pinning in bpffs and tearing down
> again. So nothing has to keep running, and each call picks up where the
> last one left off. The build records a hash of the compiled object and a
> schema version per subsystem, so a call can tell what changed. A changed
> program or map schema is swapped onto the existing links without
> interrupting traffic. The new maps are filled before the links move onto
> them. The BPF C code is also built natively against a small shim, so the
> parsing and packet building logic can be tested without a kernel.
> Packaging is debcargo like the other Rust crates.
> 
> Every change runs under a lock per subsystem, a full apply takes it
> exclusively and a single-interface step shared, like the pmxcfs domain
> locks. The holder reads the input of its change under the lock and
> writes before it lets go. So a change and a full apply reach the kernel
> in the order they read their input, and nothing has to order them after
> the fact. A holder that never returns makes the waiters time out instead
> of hanging them. A subsystem can also hand over the whole content of its
> maps. The programs then move onto the new content one link at a time and
> never read a mix of old and new entries, and a write the kernel refuses
> leaves the old content in place. The programs of different subsystems on
> one interface run in a fixed order. An attach places its link relative
> to the links the other subsystems already hold there, so the order holds
> however the attaches are timed, and an update keeps every link in its
> place.
> 
> The series applies on top of the scaffolding commit of the repo, which
> is not on the list since it carries the vendored vmlinux.h at ~167k
> lines. It is on my staff repo along with these five commits.
> 
> v5:
>  * add a call that replaces the maps as a whole, it uses more space and
>    writes everything instead of only what changed, but leaves the old
>    content in place instead of a mix, in cases where the write fails
>    with ENOMEM. Subsystems choose which they need
>  * install/upgrade now also use this newly added replace path, this
>    simplifies the process and also closes a hole where attached programs
>    would read empty maps, shortly before they were filled after a schema
>    version bump
>  * the run order of the subsystems is written to
>    `/run/proxmox-ebpf/order` by a full apply and every attach places by
>    it, so a stale process running an older version attaches correctly
>    against subsystems added by a process running a newer version
>  * set correct permissions on `/run/..`
>  * a build whose schema is older than the pinned one no longer counts
>    its state as current, so its single steps back off as well
>  * add `interrupted()` on the lock guard, true when a replacement left
>    its staged set or an old schema directory behind, a full pass
>    replaces then
>  * an attach checks after attaching that the interface still has the
>    index of its pin, one recreated under the same name in between is
>    reported as gone
>  * a map missing from a pinned set is reported by name
> 
> v4, thanks @Stefan!:
>  * drop the generation counter, a change takes the apply lock before it
>    reads its input instead, so the lock order is the input order
>  * new, the links of different subsystems on an interface are now
>    ordered
>  * the tc link plumbing is its own commit ahead of the subsystem code
>  * subsystem programs are now a list of direction and name pairs
>  * add short note for why not proxmox-sys's locking
>  * improve tc error handling
>  * fix smaller spacing and code stuff
> 
> 
> proxmox-ebpf:
> 
> Hannes Laimer (5):
>   tc: add the link plumbing
>   subsystem: add the shared tc program handling
>   subsystem: place the links of different subsystems in a fixed order
>   tests: add a native harness for the BPF C programs
>   debian: package the crate as a Rust library
> 
>  .gitignore                     |    1 +
>  Cargo.toml                     |    7 +
>  Makefile                       |   54 ++
>  build.rs                       |   68 ++
>  debian/changelog               |    5 +
>  debian/control                 |   50 ++
>  debian/copyright               |   26 +
>  debian/debcargo.toml           |   13 +
>  debian/source/format           |    1 +
>  src/bpf-shim/bpf/bpf_endian.h  |   12 +
>  src/bpf-shim/bpf/bpf_helpers.h |   34 +
>  src/bpf-shim/bpf_debug.h       |   10 +
>  src/bpf-shim/vmlinux.h         |   70 ++
>  src/lib.rs                     |    3 +
>  src/subsystem.rs               | 1146 ++++++++++++++++++++++++++++++++
>  src/tc.rs                      |  323 +++++++++
>  tests/common/mod.rs            |  207 ++++++
>  tests/harness.rs               |   64 ++
>  18 files changed, 2094 insertions(+)
>  create mode 100644 Makefile
>  create mode 100644 debian/changelog
>  create mode 100644 debian/control
>  create mode 100644 debian/copyright
>  create mode 100644 debian/debcargo.toml
>  create mode 100644 debian/source/format
>  create mode 100644 src/bpf-shim/bpf/bpf_endian.h
>  create mode 100644 src/bpf-shim/bpf/bpf_helpers.h
>  create mode 100644 src/bpf-shim/bpf_debug.h
>  create mode 100644 src/bpf-shim/vmlinux.h
>  create mode 100644 src/subsystem.rs
>  create mode 100644 src/tc.rs
>  create mode 100644 tests/common/mod.rs
>  create mode 100644 tests/harness.rs
> 
> 
> Summary over all repositories:
>   18 files changed, 2094 insertions(+), 0 deletions(-)
>