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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2010,2011 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/net/arp.h>
#include <grub/net/netbuff.h>
#include <grub/mm.h>
#include <grub/net.h>
#include <grub/net/ethernet.h>
#include <grub/net/ip.h>
#include <grub/time.h>
/* ARP header operation codes */
enum
{
ARP_REQUEST = 1,
ARP_REPLY = 2
};
enum
{
/* IANA ARP constant to define hardware type as ethernet. */
GRUB_NET_ARPHRD_ETHERNET = 1
};
struct arphdr {
grub_uint16_t hrd;
grub_uint16_t pro;
grub_uint8_t hln;
grub_uint8_t pln;
grub_uint16_t op;
} GRUB_PACKED;
static int have_pending;
static grub_uint32_t pending_req;
grub_err_t
grub_net_arp_send_request (struct grub_net_network_level_interface *inf,
const grub_net_network_level_address_t *proto_addr)
{
struct grub_net_buff nb;
struct arphdr *arp_header;
grub_net_link_level_address_t target_hw_addr;
grub_uint8_t *aux, arp_data[128];
grub_err_t err;
int i;
grub_size_t addrlen;
grub_uint16_t etherpro;
grub_uint8_t *nbd;
if (proto_addr->type == GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4)
{
addrlen = 4;
etherpro = GRUB_NET_ETHERTYPE_IP;
}
else
return grub_error (GRUB_ERR_BUG, "unsupported address family");
/* Build a request packet. */
nb.head = arp_data;
nb.end = arp_data + sizeof (arp_data);
grub_netbuff_clear (&nb);
grub_netbuff_reserve (&nb, 128);
err = grub_netbuff_push (&nb, sizeof (*arp_header) + 2 * (6 + addrlen));
if (err)
return err;
arp_header = (struct arphdr *) nb.data;
arp_header->hrd = grub_cpu_to_be16 (GRUB_NET_ARPHRD_ETHERNET);
arp_header->hln = 6;
arp_header->pro = grub_cpu_to_be16 (etherpro);
arp_header->pln = addrlen;
arp_header->op = grub_cpu_to_be16 (ARP_REQUEST);
aux = (grub_uint8_t *) arp_header + sizeof (*arp_header);
/* Sender hardware address. */
grub_memcpy (aux, &inf->hwaddress.mac, 6);
aux += 6;
/* Sender protocol address */
grub_memcpy (aux, &inf->address.ipv4, 4);
aux += addrlen;
/* Target hardware address */
for (i = 0; i < 6; i++)
aux[i] = 0x00;
aux += 6;
/* Target protocol address */
grub_memcpy (aux, &proto_addr->ipv4, 4);
grub_memset (&target_hw_addr.mac, 0xff, 6);
nbd = nb.data;
send_ethernet_packet (inf, &nb, target_hw_addr, GRUB_NET_ETHERTYPE_ARP);
for (i = 0; i < GRUB_NET_TRIES; i++)
{
if (grub_net_link_layer_resolve_check (inf, proto_addr))
return GRUB_ERR_NONE;
pending_req = proto_addr->ipv4;
have_pending = 0;
grub_net_poll_cards (GRUB_NET_INTERVAL + (i * GRUB_NET_INTERVAL_ADDITION),
&have_pending);
if (grub_net_link_layer_resolve_check (inf, proto_addr))
return GRUB_ERR_NONE;
nb.data = nbd;
send_ethernet_packet (inf, &nb, target_hw_addr, GRUB_NET_ETHERTYPE_ARP);
}
return GRUB_ERR_NONE;
}
grub_err_t
grub_net_arp_receive (struct grub_net_buff *nb,
struct grub_net_card *card)
{
struct arphdr *arp_header = (struct arphdr *) nb->data;
grub_uint8_t *sender_hardware_address;
grub_uint8_t *target_hardware_address;
grub_net_network_level_address_t sender_addr, target_addr;
grub_net_link_level_address_t sender_hw_addr;
struct grub_net_network_level_interface *inf;
grub_uint8_t *sender_protocol_address, *target_protocol_address;
sender_hardware_address =
(grub_uint8_t *) arp_header + sizeof (*arp_header);
sender_protocol_address = sender_hardware_address + arp_header->hln;
target_hardware_address = sender_protocol_address + arp_header->pln;
target_protocol_address = target_hardware_address + arp_header->hln;
if (grub_be_to_cpu16 (arp_header->pro) == GRUB_NET_ETHERTYPE_IP
&& arp_header->pln == 4)
{
sender_addr.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
target_addr.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
grub_memcpy (&sender_addr.ipv4, sender_protocol_address, 4);
grub_memcpy (&target_addr.ipv4, target_protocol_address, 4);
if (grub_memcmp (sender_protocol_address, &pending_req, 4) == 0)
have_pending = 1;
}
else
return GRUB_ERR_NONE;
sender_hw_addr.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
grub_memcpy (sender_hw_addr.mac, sender_hardware_address,
sizeof (sender_hw_addr.mac));
grub_net_link_layer_add_address (card, &sender_addr, &sender_hw_addr, 1);
FOR_NET_NETWORK_LEVEL_INTERFACES (inf)
{
/* Am I the protocol address target? */
if (grub_net_addr_cmp (&inf->address, &target_addr) == 0
&& grub_be_to_cpu16 (arp_header->op) == ARP_REQUEST)
{
grub_net_link_level_address_t target;
/* We've already checked that pln is either 4 or 16. */
char tmp[16];
grub_size_t pln = arp_header->pln;
if (pln > 16)
pln = 16;
target.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
grub_memcpy (target.mac, sender_hardware_address, 6);
grub_memcpy (target_hardware_address, target.mac, 6);
grub_memcpy (sender_hardware_address, inf->hwaddress.mac, 6);
grub_memcpy (tmp, sender_protocol_address, pln);
grub_memcpy (sender_protocol_address, target_protocol_address, pln);
grub_memcpy (target_protocol_address, tmp, pln);
/* Change operation to REPLY and send packet */
arp_header->op = grub_be_to_cpu16 (ARP_REPLY);
send_ethernet_packet (inf, nb, target, GRUB_NET_ETHERTYPE_ARP);
}
}
return GRUB_ERR_NONE;
}
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