/* Setup IPv4 + UDP header */
static void setup_header(struct net_buf *buf)
{
struct net_ipv4_hdr *ipv4;
struct net_udp_hdr *udp;
uint16_t len;
ipv4 = NET_IPV4_BUF(buf);
udp = NET_UDP_BUF(buf);
len = net_buf_frags_len(buf->frags);
/* Setup IPv4 header */
memset(ipv4, 0, sizeof(struct net_ipv4_hdr));
ipv4->vhl = 0x45;
ipv4->ttl = 0xFF;
ipv4->proto = IPPROTO_UDP;
ipv4->len[0] = len >> 8;
ipv4->len[1] = (uint8_t)len;
ipv4->chksum = ~net_calc_chksum_ipv4(buf);
net_ipaddr_copy(&ipv4->dst, net_ipv4_broadcast_address());
len -= NET_IPV4H_LEN;
/* Setup UDP header */
udp->src_port = htons(DHCPV4_CLIENT_PORT);
udp->dst_port = htons(DHCPV4_SERVER_PORT);
udp->len = htons(len);
udp->chksum = ~net_calc_chksum_udp(buf);
}
enum net_verdict net_ipv4_process_pkt(struct net_pkt *pkt)
{
struct net_ipv4_hdr *hdr = NET_IPV4_HDR(pkt);
int real_len = net_pkt_get_len(pkt);
int pkt_len = (hdr->len[0] << 8) + hdr->len[1];
enum net_verdict verdict = NET_DROP;
if (real_len != pkt_len) {
NET_DBG("IPv4 packet size %d pkt len %d", pkt_len, real_len);
goto drop;
}
#if defined(CONFIG_NET_DEBUG_IPV4)
do {
char out[sizeof("xxx.xxx.xxx.xxx")];
snprintk(out, sizeof(out), "%s",
net_sprint_ipv4_addr(&hdr->dst));
NET_DBG("IPv4 packet received from %s to %s",
net_sprint_ipv4_addr(&hdr->src), out);
} while (0);
#endif /* CONFIG_NET_DEBUG_IPV4 */
net_pkt_set_ip_hdr_len(pkt, sizeof(struct net_ipv4_hdr));
if (!net_is_my_ipv4_addr(&hdr->dst)) {
#if defined(CONFIG_NET_DHCPV4)
if (hdr->proto == IPPROTO_UDP &&
net_ipv4_addr_cmp(&hdr->dst,
net_ipv4_broadcast_address())) {
verdict = net_conn_input(IPPROTO_UDP, pkt);
if (verdict != NET_DROP) {
return verdict;
}
}
#endif
NET_DBG("IPv4 packet in pkt %p not for me", pkt);
goto drop;
}
switch (hdr->proto) {
case IPPROTO_ICMP:
verdict = process_icmpv4_pkt(pkt, hdr);
break;
case IPPROTO_UDP:
verdict = net_conn_input(IPPROTO_UDP, pkt);
break;
case IPPROTO_TCP:
verdict = net_conn_input(IPPROTO_TCP, pkt);
break;
}
if (verdict != NET_DROP) {
return verdict;
}
drop:
net_stats_update_ipv4_drop();
return NET_DROP;
}
