diff options
| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2024-03-25 13:24:13 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-03-29 08:27:50 -0700 |
| commit | 42f298c06b30bfe0a8cbee5d38644e618699e26e (patch) | |
| tree | fef5d157453ee234e7840572445922770bd90dbd /include/net/scm.h | |
| parent | 29b64e354029cfcf1eea4d91b146c7b769305930 (diff) | |
af_unix: Link struct unix_edge when queuing skb.
Just before queuing skb with inflight fds, we call scm_stat_add(),
which is a good place to set up the preallocated struct unix_vertex
and struct unix_edge in UNIXCB(skb).fp.
Then, we call unix_add_edges() and construct the directed graph
as follows:
1. Set the inflight socket's unix_sock to unix_edge.predecessor.
2. Set the receiver's unix_sock to unix_edge.successor.
3. Set the preallocated vertex to inflight socket's unix_sock.vertex.
4. Link inflight socket's unix_vertex.entry to unix_unvisited_vertices.
5. Link unix_edge.vertex_entry to the inflight socket's unix_vertex.edges.
Let's say we pass the fd of AF_UNIX socket A to B and the fd of B
to C. The graph looks like this:
+-------------------------+
| unix_unvisited_vertices | <-------------------------.
+-------------------------+ |
+ |
| +--------------+ +--------------+ | +--------------+
| | unix_sock A | <---. .---> | unix_sock B | <-|-. .---> | unix_sock C |
| +--------------+ | | +--------------+ | | | +--------------+
| .-+ | vertex | | | .-+ | vertex | | | | | vertex |
| | +--------------+ | | | +--------------+ | | | +--------------+
| | | | | | | |
| | +--------------+ | | | +--------------+ | | |
| '-> | unix_vertex | | | '-> | unix_vertex | | | |
| +--------------+ | | +--------------+ | | |
`---> | entry | +---------> | entry | +-' | |
|--------------| | | |--------------| | |
| edges | <-. | | | edges | <-. | |
+--------------+ | | | +--------------+ | | |
| | | | | |
.----------------------' | | .----------------------' | |
| | | | | |
| +--------------+ | | | +--------------+ | |
| | unix_edge | | | | | unix_edge | | |
| +--------------+ | | | +--------------+ | |
`-> | vertex_entry | | | `-> | vertex_entry | | |
|--------------| | | |--------------| | |
| predecessor | +---' | | predecessor | +---' |
|--------------| | |--------------| |
| successor | +-----' | successor | +-----'
+--------------+ +--------------+
Henceforth, we denote such a graph as A -> B (-> C).
Now, we can express all inflight fd graphs that do not contain
embryo sockets. We will support the particular case later.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20240325202425.60930-4-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include/net/scm.h')
| -rw-r--r-- | include/net/scm.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/net/scm.h b/include/net/scm.h index 5f5154e5096d..bbc5527809d1 100644 --- a/include/net/scm.h +++ b/include/net/scm.h @@ -32,6 +32,7 @@ struct scm_fp_list { short count_unix; short max; #ifdef CONFIG_UNIX + bool inflight; struct list_head vertices; struct unix_edge *edges; #endif |