SUNRPC: Recognize control messages in server-side TCP socket code

Commit Message

Chuck Lever April 17, 2023, 1:42 p.m. UTC

From: Chuck Lever <[e-mail]>

To support kTLS, the server-side TCP socket code needs to watch for
CMSGs, just like on the client side.

Signed-off-by: Chuck Lever <[e-mail]>
---
 include/net/tls.h             |    2 ++
 include/trace/events/sunrpc.h |   39 +++++++++++++++++++++++++++++++++
 net/sunrpc/svcsock.c          |   49 +++++++++++++++++++++++++++++++++++++++--
 3 files changed, 88 insertions(+), 2 deletions(-)

I'm planning to add this to nfsd-next, as it can be applied before
the net/handshake/ changes go in.

Comments

Jakub Kicinski April 20, 2023, 1:37 a.m. UTC | #1

On Mon, 17 Apr 2023 09:42:14 -0400 Chuck Lever wrote:
> From: Chuck Lever <[e-mail]>
> 
> To support kTLS, the server-side TCP socket code needs to watch for
> CMSGs, just like on the client side.
> 
> Signed-off-by: Chuck Lever <[e-mail]>

Acked-by: Jakub Kicinski <[e-mail]>

Patch

diff --git a/include/net/tls.h b/include/net/tls.h
index 154949c7b0c8..6056ce5a2aa5 100644
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -69,6 +69,8 @@  extern const struct tls_cipher_size_desc tls_cipher_size_desc[];
 
 #define TLS_CRYPTO_INFO_READY(info)	((info)->cipher_type)
 
+#define TLS_RECORD_TYPE_ALERT		0x15
+#define TLS_RECORD_TYPE_HANDSHAKE	0x16
 #define TLS_RECORD_TYPE_DATA		0x17
 
 #define TLS_AAD_SPACE_SIZE		13
diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 3ca54536f8f7..3ffb82956bd1 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -49,6 +49,19 @@  TRACE_DEFINE_ENUM(AF_INET6);
 		{ AF_INET,		"AF_INET" },		\
 		{ AF_INET6,		"AF_INET6" })
 
+/*
+ * From https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml
+ */
+#define rpc_show_tls_content_type(type) \
+	__print_symbolic(type, \
+		{ 20,		"change cipher spec" }, \
+		{ 21,		"alert" }, \
+		{ 22,		"handshake" }, \
+		{ 23,		"application data" }, \
+		{ 24,		"heartbeat" }, \
+		{ 25,		"tls12_cid" }, \
+		{ 26,		"ACK" })
+
 DECLARE_EVENT_CLASS(rpc_xdr_buf_class,
 	TP_PROTO(
 		const struct rpc_task *task,
@@ -2254,6 +2267,32 @@  DECLARE_EVENT_CLASS(svcsock_accept_class,
 DEFINE_ACCEPT_EVENT(accept);
 DEFINE_ACCEPT_EVENT(getpeername);
 
+TRACE_EVENT(svcsock_tls_ctype,
+	TP_PROTO(
+		const struct svc_xprt *xprt,
+		unsigned char ctype
+	),
+
+	TP_ARGS(xprt, ctype),
+
+	TP_STRUCT__entry(
+		SVC_XPRT_ENDPOINT_FIELDS(xprt)
+
+		__field(unsigned long, ctype)
+	),
+
+	TP_fast_assign(
+		SVC_XPRT_ENDPOINT_ASSIGNMENTS(xprt);
+
+		__entry->ctype = ctype;
+	),
+
+	TP_printk(SVC_XPRT_ENDPOINT_FORMAT " %s",
+		SVC_XPRT_ENDPOINT_VARARGS,
+		rpc_show_tls_content_type(__entry->ctype)
+	)
+);
+
 DECLARE_EVENT_CLASS(cache_event,
 	TP_PROTO(
 		const struct cache_detail *cd,
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 03a4f5615086..c8cbe3b5182d 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -43,6 +43,7 @@ 
 #include <net/udp.h>
 #include <net/tcp.h>
 #include <net/tcp_states.h>
+#include <net/tls.h>
 #include <linux/uaccess.h>
 #include <linux/highmem.h>
 #include <asm/ioctls.h>
@@ -216,6 +217,50 @@  static int svc_one_sock_name(struct svc_sock *svsk, char *buf, int remaining)
 	return len;
 }
 
+static int
+svc_tcp_sock_process_cmsg(struct svc_sock *svsk, struct msghdr *msg,
+			  struct cmsghdr *cmsg, int ret)
+{
+	if (cmsg->cmsg_level == SOL_TLS &&
+	    cmsg->cmsg_type == TLS_GET_RECORD_TYPE) {
+		u8 content_type = *((u8 *)CMSG_DATA(cmsg));
+
+		trace_svcsock_tls_ctype(&svsk->sk_xprt, content_type);
+		switch (content_type) {
+		case TLS_RECORD_TYPE_DATA:
+			/* TLS sets EOR at the end of each application data
+			 * record, even though there might be more frames
+			 * waiting to be decrypted.
+			 */
+			msg->msg_flags &= ~MSG_EOR;
+			break;
+		case TLS_RECORD_TYPE_ALERT:
+			ret = -ENOTCONN;
+			break;
+		default:
+			ret = -EAGAIN;
+		}
+	}
+	return ret;
+}
+
+static int
+svc_tcp_sock_recv_cmsg(struct svc_sock *svsk, struct msghdr *msg)
+{
+	union {
+		struct cmsghdr	cmsg;
+		u8		buf[CMSG_SPACE(sizeof(u8))];
+	} u;
+	int ret;
+
+	msg->msg_control = &u;
+	msg->msg_controllen = sizeof(u);
+	ret = sock_recvmsg(svsk->sk_sock, msg, MSG_DONTWAIT);
+	if (unlikely(msg->msg_controllen != sizeof(u)))
+		ret = svc_tcp_sock_process_cmsg(svsk, msg, &u.cmsg, ret);
+	return ret;
+}
+
 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 static void svc_flush_bvec(const struct bio_vec *bvec, size_t size, size_t seek)
 {
@@ -263,7 +308,7 @@  static ssize_t svc_tcp_read_msg(struct svc_rqst *rqstp, size_t buflen,
 		iov_iter_advance(&msg.msg_iter, seek);
 		buflen -= seek;
 	}
-	len = sock_recvmsg(svsk->sk_sock, &msg, MSG_DONTWAIT);
+	len = svc_tcp_sock_recv_cmsg(svsk, &msg);
 	if (len > 0)
 		svc_flush_bvec(bvec, len, seek);
 
@@ -877,7 +922,7 @@  static ssize_t svc_tcp_read_marker(struct svc_sock *svsk,
 		iov.iov_base = ((char *)&svsk->sk_marker) + svsk->sk_tcplen;
 		iov.iov_len  = want;
 		iov_iter_kvec(&msg.msg_iter, ITER_DEST, &iov, 1, want);
-		len = sock_recvmsg(svsk->sk_sock, &msg, MSG_DONTWAIT);
+		len = svc_tcp_sock_recv_cmsg(svsk, &msg);
 		if (len < 0)
 			return len;
 		svsk->sk_tcplen += len;