minix/drivers/dpeth/netbuff.c

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/*
** File: netbuff.c Jun. 10, 2000
**
** Author: Giovanni Falzoni <gfalzoni@inwind.it>
**
** This file contains specific implementation of buffering
** for network packets.
*/
#include <minix/drivers.h>
#include <net/gen/ether.h>
#include <net/gen/eth_io.h>
#include "dp.h"
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#if (HAVE_BUFFERS == 1)
static m_hdr_t *allocptr = NULL;
static char tx_rx_buff[8192];
/*
** Name: void *alloc_buff(dpeth_t *dep, int size)
** Function: Allocates a buffer from the common pool.
*/
PUBLIC void *alloc_buff(dpeth_t *dep, int size)
{
m_hdr_t *ptr, *wrk = allocptr;
int units = ((size + sizeof(m_hdr_t) - 1) / sizeof(m_hdr_t)) + 1;
lock();
for (ptr = wrk->next;; wrk = ptr, ptr = ptr->next) {
if (ptr->size >= units) {
/* Memory is available, carve requested size from pool */
if (ptr->size == units) {
wrk->next = ptr->next;
} else {
/* Get memory from top address */
ptr->size -= units;
ptr += ptr->size;
ptr->size = units;
}
allocptr = wrk;
unlock();
return ptr + 1;
}
if (ptr == allocptr) break;
}
unlock();
return NULL; /* No memory available */
}
/*
** Name: void free_buff(dpeth_t *dep, void *blk)
** Function: Returns a buffer to the common pool.
*/
PUBLIC void free_buff(dpeth_t *dep, void *blk)
{
m_hdr_t *wrk, *ptr = (m_hdr_t *) blk - 1;
lock(); /* Scan linked list for the correct place */
for (wrk = allocptr; !(ptr > wrk && ptr < wrk->next); wrk = wrk->next)
if (wrk >= wrk->next && (ptr > wrk || ptr < wrk->next)) break;
/* Check if adjacent block is free and join blocks */
if (ptr + ptr->size == wrk->next) {
ptr->size += wrk->next->size;
ptr->next = wrk->next->next;
} else
ptr->next = wrk->next;
if (wrk + wrk->size == ptr) {
wrk->size += ptr->size;
wrk->next = ptr->next;
} else
wrk->next = ptr;
allocptr = wrk; /* Point allocptr to block just released */
unlock();
return;
}
/*
** Name: void init_buff(dpeth_t *dep, buff_t **tx_buff)
** Function: Initalizes driver data structures.
*/
PUBLIC void init_buff(dpeth_t *dep, buff_t **tx_buff)
{
/* Initializes buffer pool */
if (allocptr == NULL) {
m_hdr_t *rx = (m_hdr_t *) tx_rx_buff;
rx->next = allocptr = rx;
rx->size = 0;
rx += 1;
rx->next = NULL;
rx->size = (sizeof(tx_rx_buff) / sizeof(m_hdr_t)) - 1;
free_buff(dep, rx + 1);
dep->de_recvq_tail = dep->de_recvq_head = NULL;
if (tx_buff != NULL) {
*tx_buff = alloc_buff(dep, ETH_MAX_PACK_SIZE + sizeof(buff_t));
(*tx_buff)->size = 0;
}
}
return; /* Done */
}
/*
** Name: void mem2user(dpeth_t *dep, buff_t *rxbuff);
** Function: Copies a packet from local buffer to user area.
*/
PUBLIC void mem2user(dpeth_t *dep, buff_t *rxbuff)
{
int bytes, ix = 0;
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iovec_dat_s_t *iovp = &dep->de_read_iovec;
int r, pktsize = rxbuff->size;
char *buffer = rxbuff->buffer;
do { /* Reads chuncks of packet into user buffers */
bytes = iovp->iod_iovec[ix].iov_size; /* Size of buffer */
if (bytes > pktsize) bytes = pktsize;
/* Reads from Rx buffer to user area */
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r= sys_safecopyto(iovp->iod_proc_nr, iovp->iod_iovec[ix].iov_grant, 0,
(vir_bytes)buffer, bytes, D);
if (r != OK)
panic("mem2user: sys_safecopyto failed: %d", r);
buffer += bytes;
if (++ix >= IOVEC_NR) { /* Next buffer of IO vector */
dp_next_iovec(iovp);
ix = 0;
}
/* Till packet done */
} while ((pktsize -= bytes) > 0);
return;
}
/*
** Name: void user2mem(dpeth_t *dep, buff_t *txbuff)
** Function: Copies a packet from user area to local buffer.
*/
PUBLIC void user2mem(dpeth_t *dep, buff_t *txbuff)
{
int bytes, ix = 0;
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iovec_dat_s_t *iovp = &dep->de_write_iovec;
int r, pktsize = txbuff->size;
char *buffer = txbuff->buffer;
do { /* Reads chuncks of packet from user buffers */
bytes = iovp->iod_iovec[ix].iov_size; /* Size of buffer */
if (bytes > pktsize) bytes = pktsize;
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r= sys_safecopyfrom(iovp->iod_proc_nr, iovp->iod_iovec[ix].iov_grant,
0, (vir_bytes)buffer, bytes, D);
if (r != OK)
panic("user2mem: sys_safecopyfrom failed: %d", r);
buffer += bytes;
if (++ix >= IOVEC_NR) { /* Next buffer of IO vector */
dp_next_iovec(iovp);
ix = 0;
}
/* Till packet done */
} while ((pktsize -= bytes) > 0);
return;
}
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#endif /* HAVE_BUFFERS */
/** netbuff.c **/