nfs/nfsd/sunrpc: enforce transport requirements for NFSv4
NFSv4 requires a transport "that is specified to avoid network
congestion" (RFC 7530, section 3.1, paragraph 2). In practical terms,
that means that you should not run NFSv4 over UDP. The server has never
enforced that requirement, however.
This patchset fixes this by adding a new flag to the svc_version that
states that it has these transport requirements. With that, we can check
that the transport has XPT_CONG_CTRL set before processing an RPC. If it
doesn't we reject it with RPC_PROG_MISMATCH.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 96467c9..e770abe 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -406,6 +406,9 @@ struct svc_version {
/* Don't care if the rpcbind registration fails */
bool vs_rpcb_optnl;
+ /* Need xprt with congestion control */
+ bool vs_need_cong_ctrl;
+
/* Override dispatch function (e.g. when caching replies).
* A return value of 0 means drop the request.
* vs_dispatch == NULL means use default dispatcher.