From: Chuck Lever <[email protected]> Kernel TCP consumers that use the read_sock interface (proto_ops.read_sock) cannot receive TLS control messages (Alerts, Handshake records) when kTLS is active. The current tls_sw_read_sock() method rejects non-data records with -EINVAL, and the sk_read_actor_t callback has no channel for delivering record- type metadata.
Four kernel subsystems are affected: NFSD (sunrpc svcsock), NFS client (sunrpc xprtsock), NVMe target (nvmet-tcp), and NVMe host (nvme-tcp). Each of these either falls back to the sock_recvmsg() API or lacks TLS alert handling entirely. A new read_sock_rectype method in struct proto_ops provides a separate code path that delivers non-data TLS records to a callback, without changing the behavior seen by existing read_sock consumers. The new sk_read_rectype_actor_t callback type extends the sk_read_actor_t signature with a rectype parameter carrying the protocol-layer record type (for example, TLS_RECORD_TYPE_ALERT). The record-type callback returns 0 to consume a record or a negative value to requeue it and stop delivery; unlike the data callback, its return value does not count bytes. Signed-off-by: Chuck Lever <[email protected]> --- include/linux/net.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/include/linux/net.h b/include/linux/net.h index 277188a40c72..7a19a743a617 100644 --- a/include/linux/net.h +++ b/include/linux/net.h @@ -198,6 +198,13 @@ struct sk_buff; struct proto_accept_arg; typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *, unsigned int, size_t); +/* rectype carries the transport record type, for example a + * TLS_RECORD_TYPE_* value. + */ +typedef int (*sk_read_rectype_actor_t)(read_descriptor_t *, + struct sk_buff *, + unsigned int, size_t, + u8 rectype); typedef int (*skb_read_actor_t)(struct sock *, struct sk_buff *); @@ -264,6 +271,27 @@ struct proto_ops { */ int (*read_sock)(struct sock *sk, read_descriptor_t *desc, sk_read_actor_t recv_actor); + /* + * read_sock_rectype splits delivery across two callbacks: + * recv_actor for data records, per the sk_read_actor_t + * convention, and rectype_actor for all other records, + * with rectype identifying each. A NULL rectype_actor + * leaves non-data records pending. rectype_actor returns 0 + * to consume a record or negative to leave it pending for + * redelivery and stop delivery; the negative return is a + * backpressure signal, not a fatal error. Both callbacks + * report errors and early stop the way recv_actor does: + * by setting desc->count to 0 and recording the reason in + * desc->error, per the read_descriptor_t convention and + * independent of the return value. The return value reports + * only data bytes consumed by recv_actor; the caller + * detects an error or early stop via desc->count and + * desc->error. + */ + int (*read_sock_rectype)(struct sock *sk, + read_descriptor_t *desc, + sk_read_actor_t recv_actor, + sk_read_rectype_actor_t rectype_actor); /* This is different from read_sock(), it reads an entire skb at a time. */ int (*read_skb)(struct sock *sk, skb_read_actor_t recv_actor); int (*sendmsg_locked)(struct sock *sk, struct msghdr *msg, -- 2.54.0
