C++ MCLGET函数代码示例

OM_uint32
gss_verify_mic(OM_uint32 *minor_status,
               const gss_ctx_id_t ctx,
               const gss_buffer_t message_buffer,
               const gss_buffer_t token_buffer,
               gss_qop_t *qop_state)
{
    OM_uint32 maj_stat;
    struct mbuf *m, *mic;

    if (!ctx) {
        *minor_status = 0;
        return (GSS_S_NO_CONTEXT);
    }

    MGET(m, M_WAITOK, MT_DATA);
    if (message_buffer->length > MLEN)
        MCLGET(m, M_WAITOK);
    m_append(m, message_buffer->length, message_buffer->value);

    MGET(mic, M_WAITOK, MT_DATA);
    if (token_buffer->length > MLEN)
        MCLGET(mic, M_WAITOK);
    m_append(mic, token_buffer->length, token_buffer->value);

    maj_stat = KGSS_VERIFY_MIC(ctx, minor_status, m, mic, qop_state);

    m_freem(m);
    m_freem(mic);

    return (maj_stat);
}

/*
 * Allocate enough mbufs to accommodate the residual count in uio,
 * and setup the uio_iov to point to them.
 *
 * This is used by the various SMB read code paths.  That code is
 * going to do a disk read into this buffer, so we'd like it to be
 * large and contiguous.  Use an external (M_EXT) buffer.
 */
struct mbuf *
smb_mbuf_allocate(struct uio *uio)
{
	mbuf_t	*m = 0;
	int	len = uio->uio_resid;

	MGET(m, M_WAIT, MT_DATA);
	if (len > MCLBYTES) {
		/* Like MCLGET(), but bigger buf. */
		m->m_ext.ext_buf = kmem_zalloc(len, KM_SLEEP);
		m->m_data = m->m_ext.ext_buf;
		m->m_flags |= M_EXT;
		m->m_ext.ext_size = len;
		m->m_ext.ext_ref = smb_mbuf_kmem_ref;
	} else if (len > MLEN) {
		/* Use the kmem cache. */
		MCLGET(m, M_WAIT);
	}
	m->m_len = len;

	uio->uio_iov->iov_base = m->m_data;
	uio->uio_iov->iov_len = m->m_len;
	uio->uio_iovcnt = 1;

	return (m);
}

/*
 * smb_mbuf_get
 *
 * Allocate mbufs to hold the amount of data specified.
 * A pointer to the head of the mbuf list is returned.
 */
struct mbuf *
smb_mbuf_get(uchar_t *buf, int nbytes)
{
	struct mbuf *mhead = 0;
	struct mbuf *m = 0;
	int count;
	int offset = 0;

	while (nbytes) {
		count = (nbytes > MCLBYTES) ? MCLBYTES : nbytes;
		nbytes -= count;

		if (mhead == 0) {
			MGET(mhead, M_WAIT, MT_DATA);
			m = mhead;
		} else {
			MGET(m->m_next, M_WAIT, MT_DATA);
			m = m->m_next;
		}

		if (count > MLEN) {
			MCLGET(m, M_WAIT);
		}

		m->m_len = count;
		bcopy(buf + offset, m->m_data, count);
		offset += count;
	}
	return (mhead);
}

/*
 * Create a "control" mbuf containing the specified data
 * with the specified type for presentation on a socket buffer.
 */
struct mbuf *
sbcreatecontrol(caddr_t p, int size, int type, int level)
{
	struct cmsghdr *cp;
	struct mbuf *m;

	if (CMSG_SPACE(size) > MCLBYTES) {
		printf("sbcreatecontrol: message too large %d\n", size);
		return NULL;
	}

	if ((m = m_get(M_DONTWAIT, MT_CONTROL)) == NULL)
		return (NULL);
	if (CMSG_SPACE(size) > MLEN) {
		MCLGET(m, M_DONTWAIT);
		if ((m->m_flags & M_EXT) == 0) {
			m_free(m);
			return NULL;
		}
	}
	cp = mtod(m, struct cmsghdr *);
	memset(cp, 0, CMSG_SPACE(size));
	memcpy(CMSG_DATA(cp), p, size);
	m->m_len = CMSG_SPACE(size);
	cp->cmsg_len = CMSG_LEN(size);
	cp->cmsg_level = level;
	cp->cmsg_type = type;
	return (m);
}

static void receive_packet(uint8_t *buffer, int length)
{
  struct ifnet *ifp = &arpcom.ac_if;
  struct mbuf *m;
  struct ether_header *eh;
  uint32_t computed_crc, net_crc;
  
  if(length < 64) {
    printk("Warning: Ethernet packet too short\n");
    return;
  }

  length -= 4; /* strip CRC */
  net_crc = ((uint32_t)buffer[length])
    | ((uint32_t)buffer[length+1] << 8)
    | ((uint32_t)buffer[length+2] << 16)
    | ((uint32_t)buffer[length+3] << 24);
  length -= 8; /* strip preamble */
  computed_crc = ether_crc32_le(&buffer[8], length) ^ 0xffffffff;
  if(computed_crc == net_crc) {
    MGETHDR(m, M_WAIT, MT_DATA);
    MCLGET(m, M_WAIT);
    length -= sizeof(struct ether_header); /* strip Ethernet header */
    memcpy(m->m_data, &buffer[8+sizeof(struct ether_header)], length);
    m->m_len = m->m_pkthdr.len = length;
    m->m_pkthdr.rcvif = ifp;
    eh = (struct ether_header *)&buffer[8];
    ether_input(ifp, eh, m);
  } else
    printk("Ethernet CRC error: got %08x expected %08x (len=%d)\n",
      net_crc, computed_crc, length);
}

static int bsd_setsockopt( cyg_file *fp, int level, int optname,
                           const void *optval, socklen_t optlen)
{
    int error;
    struct mbuf *m = NULL;
    
    if( optlen > MCLBYTES )
        return EINVAL;

    if (optval != NULL) {
        m = m_get(M_WAIT, MT_SOOPTS);
        if (optlen > MLEN) {
            MCLGET(m, M_DONTWAIT);
            if ((m->m_flags & M_EXT) == 0) {
                m_freem(m);
                return (ENOBUFS);
            }
        }
        if (m == NULL)
            return (ENOBUFS);
        error = copyin(optval, mtod(m, caddr_t), optlen);
        if (error) {
            (void) m_free(m);
            return (error);
        }
        m->m_len = optlen;
    }
    
    return (sosetopt((struct socket *)fp->f_data, level, optname, m));
}

/*
 * DON'T use free_sent_buffers to drop the queue!
 */
static void
alloc_rx_buffers(struct sbsh_softc *sc)
{
	unsigned	cur_rbd = sc->regs->LRDR & 0x7f;
	struct mbuf	*m;

	while (sc->tail_rq != ((sc->head_rq - 1) & (RQLEN - 1))) {
		MGETHDR(m, M_NOWAIT, MT_DATA);
		if (!m) {
			if_printf (&sc->arpcom.ac_if,
				   "unable to get mbuf.\n");
			return;
		}

		if (SBNI16_MAX_FRAME > MHLEN) {
			MCLGET(m, M_NOWAIT);
			if (!(m->m_flags & M_EXT)) {
				m_freem(m);
				if_printf (&sc->arpcom.ac_if,
					   "unable to get mbuf cluster.\n");
				return;
			}
			m->m_pkthdr.len = m->m_len = MCLBYTES;
		}

		m_adj(m, 2);	/* align ip on longword boundaries */

		sc->rq[sc->tail_rq++] = m;
		sc->tail_rq &= (RQLEN - 1);

		sc->rbd[cur_rbd].address = vtophys(mtod(m, vm_offset_t));
		sc->rbd[cur_rbd].length  = 0;
		sc->regs->LRDR = cur_rbd = (cur_rbd + 1) & 0x7f;
	}
}

OM_uint32
gss_get_mic(OM_uint32 *minor_status,
    const gss_ctx_id_t ctx,
    gss_qop_t qop_req,
    const gss_buffer_t message_buffer,
    gss_buffer_t message_token)
{
	OM_uint32 maj_stat;
	struct mbuf *m, *mic;

	if (!ctx) {
		*minor_status = 0;
		return (GSS_S_NO_CONTEXT);
	}

	MGET(m, M_WAITOK, MT_DATA);
	if (message_buffer->length > MLEN)
		MCLGET(m, M_WAITOK);
	m_append(m, message_buffer->length, message_buffer->value);

	maj_stat = KGSS_GET_MIC(ctx, minor_status, qop_req, m, &mic);

	m_freem(m);
	if (maj_stat == GSS_S_COMPLETE) {
		message_token->length = m_length(mic, NULL);
		message_token->value = malloc(message_token->length,
		    M_GSSAPI, M_WAITOK);
		m_copydata(mic, 0, message_token->length,
		    message_token->value);
		m_freem(mic);
	}

	return (maj_stat);
}

/*
 * Function:	mcf548x_fec_rx_bd_init
 *
 * Description:	Initialize the receive buffer descriptor ring.
 *
 * Returns:		void
 *
 * Notes:       Space for the buffers of rx BDs is allocated by the rx deamon
 *
 */
static void mcf548x_fec_rx_bd_init(struct mcf548x_enet_struct *sc) {
  int rxBdIndex;
  struct mbuf *m;
  struct ifnet *ifp = &sc->arpcom.ac_if;

  /*
   * Fill RX buffer descriptor ring.
   */
  for( rxBdIndex = 0; rxBdIndex < sc->rxBdCount; rxBdIndex++ ) {
    MGETHDR (m, M_WAIT, MT_DATA);
    MCLGET (m, M_WAIT);

    m->m_pkthdr.rcvif = ifp;
    sc->rxMbuf[rxBdIndex] = m;
    rtems_cache_invalidate_multiple_data_lines(mtod(m,const void *),
					       ETHER_MAX_LEN);
    SET_BD_BUFFER(sc->rxBd+rxBdIndex,mtod(m, void *));
    SET_BD_LENGTH(sc->rxBd+rxBdIndex,ETHER_MAX_LEN);
    SET_BD_STATUS(sc->rxBd+rxBdIndex,
		  MCF548X_FEC_RBD_EMPTY
		  | MCF548X_FEC_RBD_INT
		  | ((rxBdIndex == sc->rxBdCount-1)
		     ? MCF548X_FEC_RBD_WRAP
		     : 0));
  }
}

static struct mbuf *
repack(struct sbsh_softc *sc, struct mbuf *m)
{
	struct mbuf  *m_new;

	MGETHDR(m_new, M_NOWAIT, MT_DATA);
	if (!m_new) {
		if_printf (&sc->arpcom.ac_if,
			   "unable to get mbuf.\n");
		return (NULL);
	}

	if (m->m_pkthdr.len > MHLEN) {
		MCLGET(m_new, M_NOWAIT);
		if (!(m_new->m_flags & M_EXT)) {
			m_freem(m_new);
			if_printf (&sc->arpcom.ac_if,
				   "unable to get mbuf cluster.\n");
			return (NULL);
		}
	}

	m_copydata(m, 0, m->m_pkthdr.len, mtod(m_new, caddr_t));
	m_new->m_pkthdr.len = m_new->m_len = m->m_pkthdr.len;
	m_freem(m);
	return (m_new);
}

/*
 * Generate the rpc reply header
 * siz arg. is used to decide if adding a cluster is worthwhile
 */
struct mbuf *
nfs_rephead(int siz, struct nfsrv_descript *nd, int err,
    struct mbuf **mbp, caddr_t *bposp)
{
	u_int32_t *tl;
	struct mbuf *mreq;
	caddr_t bpos;
	struct mbuf *mb;

	if (err == EBADRPC)
		return (NULL);

	nd->nd_repstat = err;
	if (err && (nd->nd_flag & ND_NFSV3) == 0)	/* XXX recheck */
		siz = 0;

	MGET(mreq, M_WAITOK, MT_DATA);

	/*
	 * If this is a big reply, use a cluster
	 */
	mreq->m_len = 0;
	if (siz >= MINCLSIZE) {
		MCLGET(mreq, M_WAITOK);
	}
	mb = mreq;
	bpos = mtod(mb, caddr_t);

	if (err != NFSERR_RETVOID) {
		tl = nfsm_build(u_int32_t *, NFSX_UNSIGNED);
		if (err)
			*tl = txdr_unsigned(nfsrv_errmap(nd, err));
		else
			*tl = 0;
	}

unsigned char* Ecos_MemPool_Alloc (
	unsigned long Length,
	int Type)
{
    struct mbuf *pMBuf = NULL;

	switch (Type)
	{        
                case MemPool_TYPE_Header:
                        MGETHDR(pMBuf, M_DONTWAIT, MT_DATA);
                        break;
		case MemPool_TYPE_CLUSTER:
			MGETHDR(pMBuf, M_DONTWAIT, MT_DATA);
			if (pMBuf== NULL)
				return NULL;
			MCLGET(pMBuf, M_DONTWAIT);
			if ((pMBuf->m_flags & M_EXT) == 0)
                        {
				m_freem(pMBuf);
                                return NULL;
                        }
                        break;
                default:
                        DBGPRINT(RT_DEBUG_ERROR, ("%s: Unknown Type %d\n", __FUNCTION__, Type));
                        break;
	}
    
    return pMBuf;
}

/* Add a receive buffer to the indiciated descriptor. */
int
bce_add_rxbuf(struct bce_softc *sc, int idx)
{
	struct mbuf    *m;
	int             error;

	MGETHDR(m, M_DONTWAIT, MT_DATA);
	if (m == NULL)
		return (ENOBUFS);

	MCLGET(m, M_DONTWAIT);
	if ((m->m_flags & M_EXT) == 0) {
		m_freem(m);
		return (ENOBUFS);
	}
	if (sc->bce_cdata.bce_rx_chain[idx] != NULL)
		bus_dmamap_unload(sc->bce_dmatag,
		    sc->bce_cdata.bce_rx_map[idx]);

	sc->bce_cdata.bce_rx_chain[idx] = m;

	error = bus_dmamap_load(sc->bce_dmatag, sc->bce_cdata.bce_rx_map[idx],
	    m->m_ext.ext_buf, m->m_ext.ext_size, NULL,
	    BUS_DMA_READ | BUS_DMA_NOWAIT);
	if (error)
		return (error);

	bus_dmamap_sync(sc->bce_dmatag, sc->bce_cdata.bce_rx_map[idx], 0,
	    sc->bce_cdata.bce_rx_map[idx]->dm_mapsize, BUS_DMASYNC_PREREAD);

	BCE_INIT_RXDESC(sc, idx);

	return (0);

}

/*
 * Add a receive buffer to the indicated descriptor.
 */
int
ni_add_rxbuf(struct ni_softc *sc, struct ni_dg *data, int idx)
{
	struct ni_bbd *bd = &bbd[idx];
	struct mbuf *m;

	MGETHDR(m, M_DONTWAIT, MT_DATA);
	if (m == NULL)
		return (ENOBUFS);

	MCLGET(m, M_DONTWAIT);
	if ((m->m_flags & M_EXT) == 0) {
		m_freem(m);
		return (ENOBUFS);
	}

	m->m_data += 2;
	bd->nb_len = (m->m_ext.ext_size - 2);
	bd->nb_pte = (long)kvtopte(m->m_ext.ext_buf);
	bd->nb_status = 2 | NIBD_VALID;
	bd->nb_key = 1;

	data->bufs[0]._offset = 0;
	data->bufs[0]._len = bd->nb_len;
	data->bufs[0]._index = idx;
	data->nd_cmdref = (long)m;

	return (0);
}

/*
 * m_pullup2() works like m_pullup, save that len can be <= MCLBYTES.
 * m_pullup2() only works on values of len such that MHLEN < len <= MCLBYTES,
 * it calls m_pullup() for values <= MHLEN.  It also only coagulates the
 * reqested number of bytes.  (For those of us who expect unwieldly option
 * headers.
 *
 * KEBE SAYS:  Remember that dtom() calls with data in clusters does not work!
 */
struct mbuf *   
m_pullup2(struct mbuf *n, int len)       
{
	struct mbuf *m;
	int count;

	if (len <= MHLEN)
		return m_pullup(n, len);
	if ((n->m_flags & M_EXT) != 0 &&
	    n->m_data + len < &n->m_data[MCLBYTES] && n->m_next) {
		if (n->m_len >= len)
			return (n);
		m = n;
		n = n->m_next;
		len -= m->m_len;
	} else {
		if (len > MCLBYTES)
			goto bad;
		MGET(m, M_DONTWAIT, n->m_type);
		if (m == NULL)
			goto bad;
		MCLGET(m, M_DONTWAIT);
		if ((m->m_flags & M_EXT) == 0)
			goto bad;
		m->m_len = 0;
		if (n->m_flags & M_PKTHDR) {
			/* Too many adverse side effects. */
			/* M_MOVE_PKTHDR(m, n); */
			m->m_flags = (n->m_flags & M_COPYFLAGS) |
			    M_EXT | M_CLUSTER;
			M_MOVE_HDR(m, n);
			/* n->m_data is cool. */
		}
	}

	do {
		count = min(len, n->m_len);
		bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
		    (unsigned)count);
		len -= count;
		m->m_len += count;
		n->m_len -= count;
		if (n->m_len)
			n->m_data += count;
		else
			n = m_free(n);
	} while (len > 0 && n);
	if (len > 0) {
		(void)m_free(m);
		goto bad;
	}
	m->m_next = n;

	return (m);
bad:
	m_freem(n);
	MPFail++;
	return (NULL);
}