diff options
Diffstat (limited to 'grub-core/net/arp.c')
| -rw-r--r-- | grub-core/net/arp.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/grub-core/net/arp.c b/grub-core/net/arp.c new file mode 100644 index 0000000..54306e3 --- /dev/null +++ b/grub-core/net/arp.c @@ -0,0 +1,189 @@ +/* + * 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 arppkt { + grub_uint16_t hrd; + grub_uint16_t pro; + grub_uint8_t hln; + grub_uint8_t pln; + grub_uint16_t op; + grub_uint8_t sender_mac[6]; + grub_uint32_t sender_ip; + grub_uint8_t recv_mac[6]; + grub_uint32_t recv_ip; +} 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 arppkt *arp_packet; + grub_net_link_level_address_t target_mac_addr; + grub_err_t err; + int i; + grub_uint8_t *nbd; + grub_uint8_t arp_data[128]; + + if (proto_addr->type != GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4) + 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_packet)); + if (err) + return err; + + arp_packet = (struct arppkt *) nb.data; + arp_packet->hrd = grub_cpu_to_be16_compile_time (GRUB_NET_ARPHRD_ETHERNET); + arp_packet->hln = 6; + arp_packet->pro = grub_cpu_to_be16_compile_time (GRUB_NET_ETHERTYPE_IP); + arp_packet->pln = 4; + arp_packet->op = grub_cpu_to_be16_compile_time (ARP_REQUEST); + /* Sender hardware address. */ + grub_memcpy (arp_packet->sender_mac, &inf->hwaddress.mac, 6); + arp_packet->sender_ip = inf->address.ipv4; + grub_memset (arp_packet->recv_mac, 0, 6); + arp_packet->recv_ip = proto_addr->ipv4; + /* Target protocol address */ + grub_memset (&target_mac_addr.mac, 0xff, 6); + + nbd = nb.data; + send_ethernet_packet (inf, &nb, target_mac_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_mac_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, + grub_uint16_t *vlantag) +{ + struct arppkt *arp_packet = (struct arppkt *) nb->data; + grub_net_network_level_address_t sender_addr, target_addr; + grub_net_link_level_address_t sender_mac_addr; + struct grub_net_network_level_interface *inf; + + if (arp_packet->pro != grub_cpu_to_be16_compile_time (GRUB_NET_ETHERTYPE_IP) + || arp_packet->pln != 4 || arp_packet->hln != 6 + || nb->tail - nb->data < (int) sizeof (*arp_packet)) + return GRUB_ERR_NONE; + + sender_addr.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4; + target_addr.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4; + sender_addr.ipv4 = arp_packet->sender_ip; + target_addr.ipv4 = arp_packet->recv_ip; + if (arp_packet->sender_ip == pending_req) + have_pending = 1; + + sender_mac_addr.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET; + grub_memcpy (sender_mac_addr.mac, arp_packet->sender_mac, + sizeof (sender_mac_addr.mac)); + grub_net_link_layer_add_address (card, &sender_addr, &sender_mac_addr, 1); + + FOR_NET_NETWORK_LEVEL_INTERFACES (inf) + { + /* Verify vlantag id */ + if (inf->card == card && inf->vlantag != *vlantag) + { + grub_dprintf ("net", "invalid vlantag! %x != %x\n", + inf->vlantag, *vlantag); + break; + } + + /* Am I the protocol address target? */ + if (grub_net_addr_cmp (&inf->address, &target_addr) == 0 + && arp_packet->op == grub_cpu_to_be16_compile_time (ARP_REQUEST)) + { + grub_net_link_level_address_t target; + struct grub_net_buff nb_reply; + struct arppkt *arp_reply; + grub_uint8_t arp_data[128]; + grub_err_t err; + + nb_reply.head = arp_data; + nb_reply.end = arp_data + sizeof (arp_data); + grub_netbuff_clear (&nb_reply); + grub_netbuff_reserve (&nb_reply, 128); + + err = grub_netbuff_push (&nb_reply, sizeof (*arp_packet)); + if (err) + return err; + + arp_reply = (struct arppkt *) nb_reply.data; + + arp_reply->hrd = grub_cpu_to_be16_compile_time (GRUB_NET_ARPHRD_ETHERNET); + arp_reply->pro = grub_cpu_to_be16_compile_time (GRUB_NET_ETHERTYPE_IP); + arp_reply->pln = 4; + arp_reply->hln = 6; + arp_reply->op = grub_cpu_to_be16_compile_time (ARP_REPLY); + arp_reply->sender_ip = arp_packet->recv_ip; + arp_reply->recv_ip = arp_packet->sender_ip; + arp_reply->hln = 6; + + target.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET; + grub_memcpy (target.mac, arp_packet->sender_mac, 6); + grub_memcpy (arp_reply->sender_mac, inf->hwaddress.mac, 6); + grub_memcpy (arp_reply->recv_mac, arp_packet->sender_mac, 6); + + /* Change operation to REPLY and send packet */ + send_ethernet_packet (inf, &nb_reply, target, GRUB_NET_ETHERTYPE_ARP); + } + } + return GRUB_ERR_NONE; +} |