nuttx/net/arp/arp_format.c
chao an 8a63d29c6e net/devif_poll: optimize device buffer alloc in txpoll
Allocate the device buffer only if the protocol really need to send data.
not all protocols require the driver to prepare additional iob before
sending, especially UDP, each iob reserves l2/l3 header in advance
after prepare write buffer, net device could reuse this entry to send directly

Signed-off-by: chao an <anchao@xiaomi.com>
2023-01-13 16:41:10 +08:00

116 lines
3.8 KiB
C

/****************************************************************************
* net/arp/arp_format.c
*
* Copyright (C) 2007-2011, 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Based on uIP which also has a BSD style license:
*
* Author: Adam Dunkels <adam@dunkels.com>
* Copyright (c) 2001-2003, Adam Dunkels.
* 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. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <string.h>
#include <debug.h>
#include <netinet/in.h>
#include <nuttx/net/netdev.h>
#include "arp/arp.h"
#ifdef CONFIG_NET_ARP
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: arp_format
*
* Description:
* Format an ARP packet.
*
* Input Parameters:
* dev - Device structure
* ipaddr - Target IP address (32-bit)
*
* Returned Value:
* None
*
****************************************************************************/
void arp_format(FAR struct net_driver_s *dev, in_addr_t ipaddr)
{
FAR struct arp_hdr_s *arp;
FAR struct eth_hdr_s *eth;
/* Prepare device buffer before format arp */
if (netdev_iob_prepare(dev, false, 0) != OK)
{
return;
}
arp = ARPBUF;
eth = ETHBUF;
/* Construct the ARP packet. Creating both the Ethernet and ARP headers */
memset(eth->dest, 0xff, ETHER_ADDR_LEN);
memset(arp->ah_dhwaddr, 0x00, ETHER_ADDR_LEN);
memcpy(eth->src, dev->d_mac.ether.ether_addr_octet, ETHER_ADDR_LEN);
memcpy(arp->ah_shwaddr, dev->d_mac.ether.ether_addr_octet, ETHER_ADDR_LEN);
net_ipv4addr_hdrcopy(arp->ah_dipaddr, &ipaddr);
net_ipv4addr_hdrcopy(arp->ah_sipaddr, &dev->d_ipaddr);
arp->ah_opcode = HTONS(ARP_REQUEST);
arp->ah_hwtype = HTONS(ARP_HWTYPE_ETH);
arp->ah_protocol = HTONS(ETHTYPE_IP);
arp->ah_hwlen = ETHER_ADDR_LEN;
arp->ah_protolen = 4;
eth->type = HTONS(ETHTYPE_ARP);
dev->d_len = sizeof(struct arp_hdr_s) + ETH_HDRLEN;
/* Update device buffer length */
iob_update_pktlen(dev->d_iob, sizeof(struct arp_hdr_s));
}
#endif /* CONFIG_NET_ARP */