/* * Socket buffer (struct sockbuf) utility routines. * * Each socket contains two socket buffers: one for sending data and one for * receiving data. Each buffer contains a queue of mbufs, information about * the number of mbufs and amount of data in the queue, and other fields * allowing select() statements and notification on data availability to be * implemented. * * Data stored in a socket buffer is maintained as a list of records. Each * record is a list of mbufs chained together with the m_next field. Records * are chained together with the m_nextpkt field. The upper level routine * soreceive() expects the following conventions to be observed when placing * information in the receive buffer: * * 1. If the protocol requires each message be preceded by the sender's name, * then a record containing that name must be present before any * associated data (mbuf's must be of type MT_SONAME). * 2. If the protocol supports the exchange of ``access rights'' (really just * additional data associated with the message), and there are ``rights'' * to be received, then a record containing this data should be present * (mbuf's must be of type MT_RIGHTS). * 3. If a name or rights record exists, then it must be followed by a data * record, perhaps of zero length. * * Before using a new socket structure it is first necessary to reserve * buffer space to the socket, by calling sbreserve(). This should commit * some of the available buffer space in the system buffer pool for the * socket (currently, it does nothing but enforce limits). The space should * be released by calling sbrelease() when the socket is destroyed. */ int soreserve(struct socket *so, u_long sndcc, u_long rcvcc) { struct thread *td = curthread; SOCKBUF_LOCK(&so->so_snd); SOCKBUF_LOCK(&so->so_rcv); if (sbreserve_locked(&so->so_snd, sndcc, so, td) == 0) goto bad; if (sbreserve_locked(&so->so_rcv, rcvcc, so, td) == 0) goto bad2; if (so->so_rcv.sb_lowat == 0) so->so_rcv.sb_lowat = 1; if (so->so_snd.sb_lowat == 0) so->so_snd.sb_lowat = MCLBYTES; if (so->so_snd.sb_lowat > so->so_snd.sb_hiwat) so->so_snd.sb_lowat = so->so_snd.sb_hiwat; SOCKBUF_UNLOCK(&so->so_rcv); SOCKBUF_UNLOCK(&so->so_snd); return (0); bad2: sbrelease_locked(&so->so_snd, so); bad: SOCKBUF_UNLOCK(&so->so_rcv); SOCKBUF_UNLOCK(&so->so_snd); return (ENOBUFS); }
/* * Socket buffer (struct sockbuf) utility routines. * * Each socket contains two socket buffers: one for sending data and one for * receiving data. Each buffer contains a queue of mbufs, information about * the number of mbufs and amount of data in the queue, and other fields * allowing select() statements and notification on data availability to be * implemented. * * Data stored in a socket buffer is maintained as a list of records. Each * record is a list of mbufs chained together with the m_next field. Records * are chained together with the m_nextpkt field. The upper level routine * soreceive() expects the following conventions to be observed when placing * information in the receive buffer: * * 1. If the protocol requires each message be preceded by the sender's name, * then a record containing that name must be present before any * associated data (mbuf's must be of type MT_SONAME). * 2. If the protocol supports the exchange of ``access rights'' (really just * additional data associated with the message), and there are ``rights'' * to be received, then a record containing this data should be present * (mbuf's must be of type MT_RIGHTS). * 3. If a name or rights record exists, then it must be followed by a data * record, perhaps of zero length. * * Before using a new socket structure it is first necessary to reserve * buffer space to the socket, by calling sbreserve(). This should commit * some of the available buffer space in the system buffer pool for the * socket (currently, it does nothing but enforce limits). The space should * be released by calling sbrelease() when the socket is destroyed. */ int soreserve(struct socket *so, u_long sndcc, u_long rcvcc) { struct thread *td = NULL;//curthread; SOCKBUF_LOCK(&so->so_snd); SOCKBUF_LOCK(&so->so_rcv); if (sbreserve_locked(&so->so_snd, sndcc, so, td) == 0) goto bad; if (sbreserve_locked(&so->so_rcv, rcvcc, so, td) == 0) goto bad2; if (so->so_rcv.sb_lowat == 0) so->so_rcv.sb_lowat = 1;// 0x8000; if (so->so_snd.sb_lowat == 0) so->so_snd.sb_lowat = MCLBYTES; if (so->so_snd.sb_lowat > so->so_snd.sb_hiwat) so->so_snd.sb_lowat = so->so_snd.sb_hiwat; so->so_snd.sb_cc_cond = host_pthread_cond_init(); so->so_snd.sb_timeo_cond= host_pthread_cond_init(); so->so_rcv.sb_cc_cond = host_pthread_cond_init(); so->so_rcv.sb_timeo_cond= host_pthread_cond_init(); SOCKBUF_UNLOCK(&so->so_rcv); SOCKBUF_UNLOCK(&so->so_snd); return (0); bad2: sbrelease_locked(&so->so_snd, so); bad: SOCKBUF_UNLOCK(&so->so_rcv); SOCKBUF_UNLOCK(&so->so_snd); return (ENOBUFS); }
void sbrelease(struct sockbuf *sb, struct socket *so) { SOCKBUF_LOCK(sb); sbrelease_locked(sb, so); SOCKBUF_UNLOCK(sb); }