Linux ktls infrastructure

/*

 * 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 */