net/tls: allow compiling TLS TOE out

TLS "record layer offload" requires TOE, and bypasses most of
the normal networking stack. It is also significantly less
maintained. Allow users to compile it out to avoid issues.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/crypto/chelsio/Kconfig

@@ -35,7 +35,7 @@ config CHELSIO_IPSEC_INLINE
 config CRYPTO_DEV_CHELSIO_TLS
         tristate "Chelsio Crypto Inline TLS Driver"
         depends on CHELSIO_T4
-        depends on TLS
+        depends on TLS_TOE
         select CRYPTO_DEV_CHELSIO
         ---help---
           Support Chelsio Inline TLS with Chelsio crypto accelerator.

net/tls/Kconfig

@@ -26,3 +26,13 @@ config TLS_DEVICE
 	Enable kernel support for HW offload of the TLS protocol.
 
 	If unsure, say N.
+
+config TLS_TOE
+	bool "Transport Layer Security TCP stack bypass"
+	depends on TLS
+	default n
+	help
+	Enable kernel support for legacy HW offload of the TLS protocol,
+	which is incompatible with the Linux networking stack semantics.
+
+	If unsure, say N.

net/tls/Makefile

@@ -5,6 +5,7 @@
 
 obj-$(CONFIG_TLS) += tls.o
 
-tls-y := tls_main.o tls_sw.o tls_toe.o
+tls-y := tls_main.o tls_sw.o
 
+tls-$(CONFIG_TLS_TOE) += tls_toe.o
 tls-$(CONFIG_TLS_DEVICE) += tls_device.o tls_device_fallback.o

net/tls/tls_main.c

@@ -679,10 +679,11 @@ static void build_protos(struct proto prot[TLS_NUM_CONFIG][TLS_NUM_CONFIG],
 
 	prot[TLS_HW][TLS_HW] = prot[TLS_HW][TLS_SW];
 #endif
-
+#ifdef CONFIG_TLS_TOE
 	prot[TLS_HW_RECORD][TLS_HW_RECORD] = *base;
 	prot[TLS_HW_RECORD][TLS_HW_RECORD].hash		= tls_toe_hash;
 	prot[TLS_HW_RECORD][TLS_HW_RECORD].unhash	= tls_toe_unhash;
+#endif
 }
 
 static int tls_init(struct sock *sk)
@@ -692,8 +693,10 @@ static int tls_init(struct sock *sk)
 
 	tls_build_proto(sk);
 
+#ifdef CONFIG_TLS_TOE
 	if (tls_toe_bypass(sk))
 		return 0;
+#endif
 
 	/* The TLS ulp is currently supported only for TCP sockets
 	 * in ESTABLISHED state.