nuttx/net/inet/ipv4_build_header.c
Alin Jerpelea 67d02a45eb net: migrate to SPDX identifier
Most tools used for compliance and SBOM generation use SPDX identifiers
This change brings us a step closer to an easy SBOM generation.

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
2024-09-12 01:08:11 +08:00

115 lines
3.7 KiB
C

/****************************************************************************
* net/inet/ipv4_build_header.c
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <debug.h>
#include <nuttx/net/ip.h>
#include <nuttx/net/netconfig.h>
#include "inet.h"
#include "utils/utils.h"
/****************************************************************************
* Private Data
****************************************************************************/
#ifdef CONFIG_NET_IPv4
/* Increasing number used for the IP ID field. */
static uint16_t g_ipid;
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: ipv4_build_header
*
* Description:
* build IPv4 header
*
* Input Parameters:
* ipv4 Pointer to IPv4 header's buffer
* total_len total length of the IPv4 packet
* prot the next level protocol used in IPv4 packet
* src_ip Source IPv4 address
* dst_ip Destination IPv4 address
* ttl Time to live(IPv4)
* opt IPv4 options
*
* Returned Value:
* length of IPv4 header
*
****************************************************************************/
uint16_t ipv4_build_header(FAR struct ipv4_hdr_s *ipv4, uint16_t total_len,
uint16_t prot, FAR const in_addr_t *src_ip,
FAR const in_addr_t *dst_ip, uint8_t ttl,
uint8_t tos, FAR struct ipv4_opt_s *opt)
{
/* Initialize the IP header. */
ipv4->vhl = 0x45; /* orginal initial value like this */
ipv4->tos = tos;
ipv4->len[0] = (total_len >> 8);
ipv4->len[1] = (total_len & 0xff);
++g_ipid;
ipv4->ipid[0] = g_ipid >> 8;
ipv4->ipid[1] = g_ipid & 0xff;
ipv4->ipoffset[0] = IP_FLAG_DONTFRAG >> 8;
ipv4->ipoffset[1] = IP_FLAG_DONTFRAG & 0xff;
ipv4->ttl = ttl;
ipv4->proto = prot;
/* It's possible to use its own src_ip to initialize its dest_ip */
net_ipv4addr_hdrcopy(ipv4->destipaddr, dst_ip);
net_ipv4addr_hdrcopy(ipv4->srcipaddr, src_ip);
/* if ip has options, build it now */
if (opt != NULL)
{
ipv4->vhl += opt->len >> 2;
memcpy(ipv4 + 1, opt->data, opt->len);
}
/* Calculate IP checksum. */
ipv4->ipchksum = 0;
#ifdef CONFIG_NET_IPV4_CHECKSUMS
ipv4->ipchksum = ~ipv4_chksum(ipv4);
#endif
ninfo("IPv4 Packet: ipid:%d, length: %d\n", g_ipid, total_len);
return (ipv4->vhl & IPv4_HLMASK) << 2;
}
#endif /* CONFIG_NET_IPv4 */