FreeBSD/Linux Kernel Cross Reference
sys/sys/sockbuf.h

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (c) 1982, 1986, 1990, 1993
      *      The Regents of the University of California.  All rights reserved.
      *
      * 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.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
     *
     *      @(#)socketvar.h 8.3 (Berkeley) 2/19/95
     *
     * $FreeBSD: releng/12.0/sys/sys/sockbuf.h 337328 2018-08-04 20:26:54Z markj $
     */
    #ifndef _SYS_SOCKBUF_H_
    #define _SYS_SOCKBUF_H_
    
    /*
     * Constants for sb_flags field of struct sockbuf/xsockbuf.
     */
    #define SB_WAIT         0x04            /* someone is waiting for data/space */
    #define SB_SEL          0x08            /* someone is selecting */
    #define SB_ASYNC        0x10            /* ASYNC I/O, need signals */
    #define SB_UPCALL       0x20            /* someone wants an upcall */
    #define SB_NOINTR       0x40            /* operations not interruptible */
    #define SB_AIO          0x80            /* AIO operations queued */
    #define SB_KNOTE        0x100           /* kernel note attached */
    #define SB_NOCOALESCE   0x200           /* don't coalesce new data into existing mbufs */
    #define SB_IN_TOE       0x400           /* socket buffer is in the middle of an operation */
    #define SB_AUTOSIZE     0x800           /* automatically size socket buffer */
    #define SB_STOP         0x1000          /* backpressure indicator */
    #define SB_AIO_RUNNING  0x2000          /* AIO operation running */
    
    #define SBS_CANTSENDMORE        0x0010  /* can't send more data to peer */
    #define SBS_CANTRCVMORE         0x0020  /* can't receive more data from peer */
    #define SBS_RCVATMARK           0x0040  /* at mark on input */
    
    #if defined(_KERNEL) || defined(_WANT_SOCKET)
    #include <sys/_lock.h>
    #include <sys/_mutex.h>
    #include <sys/_sx.h>
    #include <sys/_task.h>
    
    #define SB_MAX          (2*1024*1024)   /* default for max chars in sockbuf */
    
    struct mbuf;
    struct sockaddr;
    struct socket;
    struct thread;
    struct selinfo;
    
    /*
     * Variables for socket buffering.
     *
     * Locking key to struct sockbuf:
     * (a) locked by SOCKBUF_LOCK().
     */
    struct  sockbuf {
            struct  mtx sb_mtx;             /* sockbuf lock */
            struct  sx sb_sx;               /* prevent I/O interlacing */
            struct  selinfo *sb_sel;        /* process selecting read/write */
            short   sb_state;       /* (a) socket state on sockbuf */
    #define sb_startzero    sb_mb
            struct  mbuf *sb_mb;    /* (a) the mbuf chain */
            struct  mbuf *sb_mbtail; /* (a) the last mbuf in the chain */
            struct  mbuf *sb_lastrecord;    /* (a) first mbuf of last
                                             * record in socket buffer */
            struct  mbuf *sb_sndptr; /* (a) pointer into mbuf chain */
            struct  mbuf *sb_fnrdy; /* (a) pointer to first not ready buffer */
            u_int   sb_sndptroff;   /* (a) byte offset of ptr into chain */
            u_int   sb_acc;         /* (a) available chars in buffer */
            u_int   sb_ccc;         /* (a) claimed chars in buffer */
            u_int   sb_hiwat;       /* (a) max actual char count */
            u_int   sb_mbcnt;       /* (a) chars of mbufs used */
            u_int   sb_mcnt;        /* (a) number of mbufs in buffer */
            u_int   sb_ccnt;        /* (a) number of clusters in buffer */
            u_int   sb_mbmax;       /* (a) max chars of mbufs to use */
            u_int   sb_ctl;         /* (a) non-data chars in buffer */
            int     sb_lowat;       /* (a) low water mark */
           sbintime_t      sb_timeo;       /* (a) timeout for read/write */
           short   sb_flags;       /* (a) flags, see below */
           int     (*sb_upcall)(struct socket *, void *, int); /* (a) */
           void    *sb_upcallarg;  /* (a) */
           TAILQ_HEAD(, kaiocb) sb_aiojobq; /* (a) pending AIO ops */
           struct  task sb_aiotask; /* AIO task */
   };
   
   #endif  /* defined(_KERNEL) || defined(_WANT_SOCKET) */
   #ifdef _KERNEL
   
   /*
    * Per-socket buffer mutex used to protect most fields in the socket
    * buffer.
    */
   #define SOCKBUF_MTX(_sb)                (&(_sb)->sb_mtx)
   #define SOCKBUF_LOCK_INIT(_sb, _name) \
           mtx_init(SOCKBUF_MTX(_sb), _name, NULL, MTX_DEF)
   #define SOCKBUF_LOCK_DESTROY(_sb)       mtx_destroy(SOCKBUF_MTX(_sb))
   #define SOCKBUF_LOCK(_sb)               mtx_lock(SOCKBUF_MTX(_sb))
   #define SOCKBUF_OWNED(_sb)              mtx_owned(SOCKBUF_MTX(_sb))
   #define SOCKBUF_UNLOCK(_sb)             mtx_unlock(SOCKBUF_MTX(_sb))
   #define SOCKBUF_LOCK_ASSERT(_sb)        mtx_assert(SOCKBUF_MTX(_sb), MA_OWNED)
   #define SOCKBUF_UNLOCK_ASSERT(_sb)      mtx_assert(SOCKBUF_MTX(_sb), MA_NOTOWNED)
   
   /*
    * Socket buffer private mbuf(9) flags.
    */
   #define M_NOTREADY      M_PROTO1        /* m_data not populated yet */
   #define M_BLOCKED       M_PROTO2        /* M_NOTREADY in front of m */
   #define M_NOTAVAIL      (M_NOTREADY | M_BLOCKED)
   
   void    sbappend(struct sockbuf *sb, struct mbuf *m, int flags);
   void    sbappend_locked(struct sockbuf *sb, struct mbuf *m, int flags);
   void    sbappendstream(struct sockbuf *sb, struct mbuf *m, int flags);
   void    sbappendstream_locked(struct sockbuf *sb, struct mbuf *m, int flags);
   int     sbappendaddr(struct sockbuf *sb, const struct sockaddr *asa,
               struct mbuf *m0, struct mbuf *control);
   int     sbappendaddr_locked(struct sockbuf *sb, const struct sockaddr *asa,
               struct mbuf *m0, struct mbuf *control);
   int     sbappendaddr_nospacecheck_locked(struct sockbuf *sb,
               const struct sockaddr *asa, struct mbuf *m0, struct mbuf *control);
   void    sbappendcontrol(struct sockbuf *sb, struct mbuf *m0,
               struct mbuf *control);
   void    sbappendcontrol_locked(struct sockbuf *sb, struct mbuf *m0,
               struct mbuf *control);
   void    sbappendrecord(struct sockbuf *sb, struct mbuf *m0);
   void    sbappendrecord_locked(struct sockbuf *sb, struct mbuf *m0);
   void    sbcompress(struct sockbuf *sb, struct mbuf *m, struct mbuf *n);
   struct mbuf *
           sbcreatecontrol(caddr_t p, int size, int type, int level);
   void    sbdestroy(struct sockbuf *sb, struct socket *so);
   void    sbdrop(struct sockbuf *sb, int len);
   void    sbdrop_locked(struct sockbuf *sb, int len);
   struct mbuf *
           sbcut_locked(struct sockbuf *sb, int len);
   void    sbdroprecord(struct sockbuf *sb);
   void    sbdroprecord_locked(struct sockbuf *sb);
   void    sbflush(struct sockbuf *sb);
   void    sbflush_locked(struct sockbuf *sb);
   void    sbrelease(struct sockbuf *sb, struct socket *so);
   void    sbrelease_internal(struct sockbuf *sb, struct socket *so);
   void    sbrelease_locked(struct sockbuf *sb, struct socket *so);
   int     sbsetopt(struct socket *so, int cmd, u_long cc);
   int     sbreserve_locked(struct sockbuf *sb, u_long cc, struct socket *so,
               struct thread *td);
   struct mbuf *
           sbsndptr(struct sockbuf *sb, u_int off, u_int len, u_int *moff);
   struct mbuf *
           sbsndptr_noadv(struct sockbuf *sb, u_int off, u_int *moff);
   void
           sbsndptr_adv(struct sockbuf *sb, struct mbuf *mb, u_int len);
   struct mbuf *
           sbsndmbuf(struct sockbuf *sb, u_int off, u_int *moff);
   int     sbwait(struct sockbuf *sb);
   int     sblock(struct sockbuf *sb, int flags);
   void    sbunlock(struct sockbuf *sb);
   void    sballoc(struct sockbuf *, struct mbuf *);
   void    sbfree(struct sockbuf *, struct mbuf *);
   int     sbready(struct sockbuf *, struct mbuf *, int);
   
   /*
    * Return how much data is available to be taken out of socket
    * buffer right now.
    */
   static inline u_int
   sbavail(struct sockbuf *sb)
   {
   
   #if 0
           SOCKBUF_LOCK_ASSERT(sb);
   #endif
           return (sb->sb_acc);
   }
   
   /*
    * Return how much data sits there in the socket buffer
    * It might be that some data is not yet ready to be read.
    */
   static inline u_int
   sbused(struct sockbuf *sb)
   {
   
   #if 0
           SOCKBUF_LOCK_ASSERT(sb);
   #endif
           return (sb->sb_ccc);
   }
   
   /*
    * How much space is there in a socket buffer (so->so_snd or so->so_rcv)?
    * This is problematical if the fields are unsigned, as the space might
    * still be negative (ccc > hiwat or mbcnt > mbmax).
    */
   static inline long
   sbspace(struct sockbuf *sb)
   {
           int bleft, mleft;               /* size should match sockbuf fields */
   
   #if 0
           SOCKBUF_LOCK_ASSERT(sb);
   #endif
   
           if (sb->sb_flags & SB_STOP)
                   return(0);
   
           bleft = sb->sb_hiwat - sb->sb_ccc;
           mleft = sb->sb_mbmax - sb->sb_mbcnt;
   
           return ((bleft < mleft) ? bleft : mleft);
   }
   
   #define SB_EMPTY_FIXUP(sb) do {                                         \
           if ((sb)->sb_mb == NULL) {                                      \
                   (sb)->sb_mbtail = NULL;                                 \
                   (sb)->sb_lastrecord = NULL;                             \
           }                                                               \
   } while (/*CONSTCOND*/0)
   
   #ifdef SOCKBUF_DEBUG
   void    sblastrecordchk(struct sockbuf *, const char *, int);
   void    sblastmbufchk(struct sockbuf *, const char *, int);
   void    sbcheck(struct sockbuf *, const char *, int);
   #define SBLASTRECORDCHK(sb)     sblastrecordchk((sb), __FILE__, __LINE__)
   #define SBLASTMBUFCHK(sb)       sblastmbufchk((sb), __FILE__, __LINE__)
   #define SBCHECK(sb)             sbcheck((sb), __FILE__, __LINE__)
   #else
   #define SBLASTRECORDCHK(sb)     do {} while (0)
   #define SBLASTMBUFCHK(sb)       do {} while (0)
   #define SBCHECK(sb)             do {} while (0)
   #endif /* SOCKBUF_DEBUG */
   
   #endif /* _KERNEL */
   
   #endif /* _SYS_SOCKBUF_H_ */

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