void uip_build_arp_request(struct uip_stack *ustack, u16_t *ipaddr)
{
struct arp_hdr *arp;
struct uip_eth_hdr *eth;
arp = (struct arp_hdr *)ustack->network_layer;
eth = (struct uip_eth_hdr *)ustack->data_link_layer;
/* The destination address was not in our ARP table, so we
overwrite the IP packet with an ARP request. */
memset(eth->dest.addr, 0xff, 6);
memset(arp->dhwaddr.addr, 0x00, 6);
memcpy(eth->src.addr, ustack->uip_ethaddr.addr, 6);
memcpy(arp->shwaddr.addr, ustack->uip_ethaddr.addr, 6);
uip_ip4addr_copy(arp->dipaddr, ipaddr);
uip_ip4addr_copy(arp->sipaddr, ustack->hostaddr);
arp->opcode = const_htons(ARP_REQUEST); /* ARP request. */
arp->hwtype = const_htons(ARP_HWTYPE_ETH);
arp->protocol = const_htons(UIP_ETHTYPE_IPv4);
arp->hwlen = 6;
arp->protolen = 4;
eth->type = const_htons(UIP_ETHTYPE_ARP);
ustack->uip_appdata = &ustack->uip_buf[UIP_TCP_IPv4_HLEN + UIP_LLH_LEN];
ustack->uip_len = sizeof(*arp) + sizeof(*eth);
}
void
uip_arp_arpin(nic_interface_t *nic_iface,
struct uip_stack *ustack, packet_t *pkt)
{
struct arp_hdr *arp;
struct uip_eth_hdr *eth;
if (pkt->buf_size < sizeof(struct arp_hdr)) {
pkt->buf_size = 0;
return;
}
pkt->buf_size = 0;
eth = (struct uip_eth_hdr *)pkt->data_link_layer;
arp = (struct arp_hdr *)pkt->network_layer;
switch (arp->opcode) {
case const_htons(ARP_REQUEST):
/* ARP request. If it asked for our address, we send out a
reply. */
if (uip_ip4addr_cmp(arp->dipaddr, ustack->hostaddr)) {
/* First, we register the one who made the request in
our ARP table, since it is likely that we will do
more communication with this host in the future. */
uip_arp_update(arp->sipaddr, &arp->shwaddr);
/* The reply opcode is 2. */
arp->opcode = htons(2);
memcpy(arp->dhwaddr.addr, arp->shwaddr.addr, 6);
memcpy(arp->shwaddr.addr, ustack->uip_ethaddr.addr, 6);
memcpy(eth->src.addr, ustack->uip_ethaddr.addr, 6);
memcpy(eth->dest.addr, arp->dhwaddr.addr, 6);
arp->dipaddr[0] = arp->sipaddr[0];
arp->dipaddr[1] = arp->sipaddr[1];
arp->sipaddr[0] = ustack->hostaddr[0];
arp->sipaddr[1] = ustack->hostaddr[1];
if (nic_iface->vlan_id == 0) {
eth->type = htons(UIP_ETHTYPE_ARP);
pkt->buf_size = sizeof(*arp) + sizeof(*eth);
} else {
eth->type = htons(UIP_ETHTYPE_8021Q);
pkt->buf_size = sizeof(*arp) +
sizeof(struct uip_vlan_eth_hdr);
}
}
break;
case const_htons(ARP_REPLY):
uip_arp_update(arp->sipaddr, &arp->shwaddr);
break;
default:
LOG_WARN("Unknown ARP opcode: %d", ntohs(arp->opcode));
break;
}
return;
}
int is_vlan_packet(struct uip_vlan_eth_hdr *hdr)
{
/* The TPID field in a 802.1Q Header must be 0x8100 */
if (hdr->tpid == const_htons(UIP_ETHTYPE_8021Q))
return 1;
return 0;
}