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#include "decode_ipv4.h"
#define IPV4_GET_HLEN(ip4_hdr) (((ip4_hdr)->ip_verhl & 0x0f) << 2)
#define IPV4_GET_IPPROTO(ip4_hdr) ((ip4_hdr)->ip_proto)
#define IPV4_GET_IPLEN(ip4_hdr) ((uint16_t)ntohs((ip4_hdr)->ip_len))
#define IPV4_GET_SRC_ADDR(ip4_hdr) ((ip4_hdr)->ip4_hdrun1.ip4_un1.ip_src)
#define IPV4_GET_DST_ADDR(ip4_hdr) ((ip4_hdr)->ip4_hdrun1.ip4_un1.ip_dst)
int decode_ipv4(ipv4_info_t *packet, const uint8_t *data, uint32_t len)
{
// 检查包长是否大于 IPv4 header
if (len < IPV4_HEADER_LEN)
{
LOG_ERROR("Parser IPv4 Header: packet length too small %d", len);
return -1;
}
// 检查 IPv4 header version
if (IP_GET_RAW_VER(data) != 4)
{
LOG_ERROR("Parser IPv4 Header: invalid IP version %d", IP_GET_RAW_VER(data));
return -1;
}
packet->hdr = (ipv4_header_t *)data;
// 检查 IPv4 header length
if (IPV4_GET_HLEN(packet->hdr) < IPV4_HEADER_LEN)
{
LOG_ERROR("Parser IPv4 Header: invalid IP header length %d", IPV4_GET_HLEN(packet->hdr));
return -1;
}
// 检查 IPv4 header total length
if (IPV4_GET_IPLEN(packet->hdr) < IPV4_GET_HLEN(packet->hdr))
{
LOG_ERROR("Parser IPv4 Header: invalid IP header total length %d", IPV4_GET_IPLEN(packet->hdr));
return -1;
}
// 检查是否 IP 分片
if (len < IPV4_GET_IPLEN(packet->hdr))
{
LOG_ERROR("Parser IPv4 Header: trunc packet");
return -1;
}
inet_ntop(AF_INET, &IPV4_GET_SRC_ADDR(packet->hdr), packet->src_addr, sizeof(packet->src_addr));
inet_ntop(AF_INET, &IPV4_GET_DST_ADDR(packet->hdr), packet->dst_addr, sizeof(packet->dst_addr));
packet->next_protocol = IPV4_GET_IPPROTO(packet->hdr);
packet->hdr_len = IPV4_GET_HLEN(packet->hdr);
packet->opts_len = packet->hdr_len - IPV4_HEADER_LEN;
packet->payload_len = len - packet->hdr_len;
packet->payload = (uint8_t *)data + packet->hdr_len;
return 0;
}
void dump_ipv4_info(uint32_t pkt_id, ipv4_info_t *packet)
{
LOG_DEBUG("id: %u, ipv4_info: {src_addr: %s, dst_addr: %s, hdr_len: %u, opt_len: %u, data_len: %u}",
pkt_id,
packet->src_addr,
packet->dst_addr,
packet->hdr_len,
packet->opts_len,
packet->payload_len);
}
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