FreeBSD/Linux Kernel Cross Reference
sys/dev/tcp_log/tcp_log_dev.h

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2016 Netflix, Inc.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD$
     */
    
    #ifndef __tcp_log_dev_h__
    #define __tcp_log_dev_h__
    
    /*
     * This is the common header for data streamed from the log device. All
     * blocks of data need to start with this header.
     */
    struct tcp_log_common_header {
            uint32_t        tlch_version;   /* Version is specific to type. */
            uint32_t        tlch_type;      /* Type of entry(ies) that follow. */
            uint64_t        tlch_length;    /* Total length, including header. */
    } __packed;
    
    #define TCP_LOG_DEV_TYPE_BBR    1       /* black box recorder */
    
    #ifdef _KERNEL
    /*
     * This is a queue entry. All queue entries need to start with this structure
     * so the common code can cast them to this structure; however, other modules
     * are free to include additional data after this structure.
     *
     * The elements are explained here:
     * tldq_queue: used by the common code to maintain this entry's position in the
     *     queue.
     * tldq_buf: should be NULL, or a pointer to a chunk of data. The data must be
     *     as long as the common header indicates.
     * tldq_xform: If tldq_buf is NULL, the code will call this to create the
     *     the tldq_buf object. The function should *not* directly modify tldq_buf,
     *     but should return the buffer (which must meet the restrictions
     *     indicated for tldq_buf).
     * tldq_dtor: This function is called to free the queue entry. If tldq_buf is
     *     not NULL, the dtor function must free that, too.
     * tldq_refcnt: used by the common code to indicate how many readers still need
     *     this data.
     */
    struct tcp_log_dev_queue {
            STAILQ_ENTRY(tcp_log_dev_queue) tldq_queue;
            struct tcp_log_common_header *tldq_buf;
            struct tcp_log_common_header *(*tldq_xform)(struct tcp_log_dev_queue *entry);
            void    (*tldq_dtor)(struct tcp_log_dev_queue *entry);
            volatile u_int tldq_refcnt;
    };
    
    STAILQ_HEAD(log_queueh, tcp_log_dev_queue);
    
    struct tcp_log_dev_info {
            STAILQ_ENTRY(tcp_log_dev_info) tldi_list;
            struct tcp_log_dev_queue *tldi_head;
            struct tcp_log_common_header *tldi_cur;
            off_t                   tldi_off;
    };
    STAILQ_HEAD(log_infoh, tcp_log_dev_info);
    
    #ifdef TCP_BLACKBOX
    MALLOC_DECLARE(M_TCPLOGDEV);
    int tcp_log_dev_add_log(struct tcp_log_dev_queue *entry);
    #endif /* TCP_BLACKBOX */
    #endif /* _KERNEL */
    #endif /* !__tcp_log_dev_h__ */

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