Linux ktls infrastructure

Introduce a compatability layer that exposes the required structures
and constants for supporting ktls.

Signed-off-by: Boris Pismenny <borisp@mellanox.com>

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Paul Yang <yang.yang@baishancloud.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5253)

include/internal/ktls.h

@@ -0,0 +1,147 @@
+/*
+ * Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#ifndef OPENSSL_NO_KTLS
+# ifndef HEADER_INTERNAL_KTLS
+#  define HEADER_INTERNAL_KTLS
+
+#  if defined(OPENSSL_SYS_LINUX)
+#   include <linux/version.h>
+
+#   define K_MAJ   4
+#   define K_MIN1  13
+#   define K_MIN2  0
+#   if LINUX_VERSION_CODE < KERNEL_VERSION(K_MAJ, K_MIN1, K_MIN2)
+
+#    ifndef PEDANTIC
+#     warning "KTLS requires Kernel Headers >= 4.13.0"
+#     warning "Skipping Compilation of KTLS data path"
+#    endif
+
+#    define TLS_TX                  1
+
+#    define TLS_CIPHER_AES_GCM_128                          51
+#    define TLS_CIPHER_AES_GCM_128_IV_SIZE                  8
+#    define TLS_CIPHER_AES_GCM_128_KEY_SIZE                 16
+#    define TLS_CIPHER_AES_GCM_128_SALT_SIZE                4
+#    define TLS_CIPHER_AES_GCM_128_TAG_SIZE                 16
+#    define TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE             8
+
+#    define TLS_SET_RECORD_TYPE     1
+
+struct tls_crypto_info {
+    unsigned short version;
+    unsigned short cipher_type;
+};
+
+struct tls12_crypto_info_aes_gcm_128 {
+    struct tls_crypto_info info;
+    unsigned char iv[TLS_CIPHER_AES_GCM_128_IV_SIZE];
+    unsigned char key[TLS_CIPHER_AES_GCM_128_KEY_SIZE];
+    unsigned char salt[TLS_CIPHER_AES_GCM_128_SALT_SIZE];
+    unsigned char rec_seq[TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE];
+};
+
+/* Dummy functions here */
+static ossl_inline int ktls_enable(int fd)
+{
+    return 0;
+}
+
+static ossl_inline int ktls_start(int fd,
+                                  struct tls12_crypto_info_aes_gcm_128
+                                  *crypto_info, size_t len, int is_tx)
+{
+    return 0;
+}
+
+static ossl_inline int ktls_send_ctrl_message(int fd, unsigned char record_type,
+                                              const void *data, size_t length)
+{
+    return -1;
+}
+
+#   else                        /* KERNEL_VERSION */
+
+#    include <netinet/tcp.h>
+#    include <linux/tls.h>
+#    include <linux/socket.h>
+
+#    ifndef SOL_TLS
+#     define SOL_TLS 282
+#    endif
+
+#    ifndef TCP_ULP
+#     define TCP_ULP 31
+#    endif
+
+/*
+ * When successful, this socket option doesn't change the behaviour of the
+ * TCP socket, except changing the TCP setsockopt handler to enable the
+ * processing of SOL_TLS socket options. All other functionality remains the
+ * same.
+ */
+static ossl_inline int ktls_enable(int fd)
+{
+    return setsockopt(fd, SOL_TCP, TCP_ULP, "tls", sizeof("tls")) ? 0 : 1;
+}
+
+/*
+ * The TLS_TX socket option changes the send/sendmsg handlers of the TCP socket.
+ * If successful, then data sent using this socket will be encrypted and
+ * encapsulated in TLS records using the crypto_info provided here.
+ */
+static ossl_inline int ktls_start(int fd,
+                                  struct tls12_crypto_info_aes_gcm_128
+                                  *crypto_info, size_t len, int is_tx)
+{
+    if (is_tx)
+        return setsockopt(fd, SOL_TLS, TLS_TX, crypto_info,
+                          sizeof(*crypto_info)) ? 0 : 1;
+    else
+        return 0;
+}
+
+/*
+ * Send a TLS record using the crypto_info provided in ktls_start and use
+ * record_type instead of the default SSL3_RT_APPLICATION_DATA.
+ * When the socket is non-blocking, then this call either returns EAGAIN or
+ * the entire record is pushed to TCP. It is impossible to send a partial
+ * record using this control message.
+ */
+static ossl_inline int ktls_send_ctrl_message(int fd, unsigned char record_type,
+                                              const void *data, size_t length)
+{
+    struct msghdr msg = { 0 };
+    int cmsg_len = sizeof(record_type);
+    struct cmsghdr *cmsg;
+    char buf[CMSG_SPACE(cmsg_len)];
+    struct iovec msg_iov;       /* Vector of data to send/receive into */
+
+    msg.msg_control = buf;
+    msg.msg_controllen = sizeof(buf);
+    cmsg = CMSG_FIRSTHDR(&msg);
+    cmsg->cmsg_level = SOL_TLS;
+    cmsg->cmsg_type = TLS_SET_RECORD_TYPE;
+    cmsg->cmsg_len = CMSG_LEN(cmsg_len);
+    *((unsigned char *)CMSG_DATA(cmsg)) = record_type;
+    msg.msg_controllen = cmsg->cmsg_len;
+
+    msg_iov.iov_base = (void *)data;
+    msg_iov.iov_len = length;
+    msg.msg_iov = &msg_iov;
+    msg.msg_iovlen = 1;
+
+    return sendmsg(fd, &msg, 0);
+}
+
+#   endif                       /* KERNEL_VERSION */
+#  endif                        /* OPENSSL_SYS_LINUX */
+# endif                         /* HEADER_INTERNAL_KTLS */
+#endif                          /* OPENSSL_NO_KTLS */