| /* |
| * Copyright (c) 2001-2002, Adam Dunkels. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. All advertising materials mentioning features or use of this software |
| * must display the following acknowledgement: |
| * This product includes software developed by Adam Dunkels. |
| * 4. The name of the author may not be used to endorse or promote |
| * products derived from this software without specific prior |
| * written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS |
| * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
| * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE |
| * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| * This file is part of the uIP TCP/IP stack. |
| * |
| * $Id: uip_arp.c,v 1.3 2003/06/30 20:36:28 adamdunkels Exp $ |
| * |
| */ |
| |
| |
| #include "uip_arp.h" |
| |
| struct arp_hdr { |
| struct uip_eth_hdr ethhdr; |
| u16_t hwtype; |
| u16_t protocol; |
| u8_t hwlen; |
| u8_t protolen; |
| u16_t opcode; |
| struct uip_eth_addr shwaddr; |
| u16_t sipaddr[2]; |
| struct uip_eth_addr dhwaddr; |
| u16_t dipaddr[2]; |
| }; |
| |
| struct ethip_hdr { |
| struct uip_eth_hdr ethhdr; |
| /* IP header. */ |
| u8_t vhl, |
| tos, |
| len[2], |
| ipid[2], |
| ipoffset[2], |
| ttl, |
| proto; |
| u16_t ipchksum; |
| u16_t srcipaddr[2], |
| destipaddr[2]; |
| }; |
| |
| #define ARP_REQUEST 1 |
| #define ARP_REPLY 2 |
| |
| #define ARP_HWTYPE_ETH 1 |
| |
| u16_t uip_arp_draddr[2], uip_arp_netmask[2]; |
| |
| struct arp_entry { |
| u16_t ipaddr[2]; |
| struct uip_eth_addr ethaddr; |
| u8_t time; |
| }; |
| |
| struct uip_eth_addr uip_ethaddr = {{UIP_ETHADDR0, |
| UIP_ETHADDR1, |
| UIP_ETHADDR2, |
| UIP_ETHADDR3, |
| UIP_ETHADDR4, |
| UIP_ETHADDR5}}; |
| |
| static struct arp_entry arp_table[UIP_ARPTAB_SIZE]; |
| static u16_t ipaddr[2]; |
| static u8_t i, c; |
| |
| static u8_t arptime; |
| static u8_t tmpage; |
| |
| #define BUF ((struct arp_hdr *)&uip_buf[0]) |
| #define IPBUF ((struct ethip_hdr *)&uip_buf[0]) |
| /*-----------------------------------------------------------------------------------*/ |
| void |
| uip_arp_init(void) |
| { |
| for(i = 0; i < UIP_ARPTAB_SIZE; ++i) { |
| arp_table[i].ipaddr[0] = |
| arp_table[i].ipaddr[1] = 0; |
| } |
| } |
| /*-----------------------------------------------------------------------------------*/ |
| void |
| uip_arp_timer(void) |
| { |
| ++arptime; |
| for(i = 0; i < UIP_ARPTAB_SIZE; ++i) { |
| if((arp_table[i].ipaddr[0] | arp_table[i].ipaddr[1]) != 0 && |
| arptime - arp_table[i].time >= UIP_ARP_MAXAGE) { |
| arp_table[i].ipaddr[0] = |
| arp_table[i].ipaddr[1] = 0; |
| } |
| } |
| |
| } |
| /*-----------------------------------------------------------------------------------*/ |
| static void |
| uip_arp_update(u16_t *ipaddr, struct uip_eth_addr *ethaddr) |
| { |
| /* Walk through the ARP mapping table and try to find an entry to |
| update. If none is found, the IP -> MAC address mapping is |
| inserted in the ARP table. */ |
| for(i = 0; i < UIP_ARPTAB_SIZE; ++i) { |
| |
| /* Only check those entries that are actually in use. */ |
| if(arp_table[i].ipaddr[0] != 0 && |
| arp_table[i].ipaddr[1] != 0) { |
| |
| /* Check if the source IP address of the incoming packet matches |
| the IP address in this ARP table entry. */ |
| if(ipaddr[0] == arp_table[i].ipaddr[0] && |
| ipaddr[1] == arp_table[i].ipaddr[1]) { |
| |
| /* An old entry found, update this and return. */ |
| for(c = 0; c < 6; ++c) { |
| arp_table[i].ethaddr.addr[c] = ethaddr->addr[c]; |
| } |
| arp_table[i].time = arptime; |
| |
| return; |
| } |
| } |
| } |
| |
| /* If we get here, no existing ARP table entry was found, so we |
| create one. */ |
| |
| /* First, we try to find an unused entry in the ARP table. */ |
| for(i = 0; i < UIP_ARPTAB_SIZE; ++i) { |
| if(arp_table[i].ipaddr[0] == 0 && |
| arp_table[i].ipaddr[1] == 0) { |
| break; |
| } |
| } |
| |
| /* If no unused entry is found, we try to find the oldest entry and |
| throw it away. */ |
| if(i == UIP_ARPTAB_SIZE) { |
| tmpage = 0; |
| c = 0; |
| for(i = 0; i < UIP_ARPTAB_SIZE; ++i) { |
| if(arptime - arp_table[i].time > tmpage) { |
| tmpage = arptime - arp_table[i].time; |
| c = i; |
| } |
| } |
| i = c; |
| } |
| |
| /* Now, i is the ARP table entry which we will fill with the new |
| information. */ |
| arp_table[i].ipaddr[0] = ipaddr[0]; |
| arp_table[i].ipaddr[1] = ipaddr[1]; |
| for(c = 0; c < 6; ++c) { |
| arp_table[i].ethaddr.addr[c] = ethaddr->addr[c]; |
| } |
| arp_table[i].time = arptime; |
| } |
| /*-----------------------------------------------------------------------------------*/ |
| void |
| uip_arp_ipin(void) |
| { |
| |
| /* Only insert/update an entry if the source IP address of the |
| incoming IP packet comes from a host on the local network. */ |
| /* if((IPBUF->srcipaddr[0] & HTONS((UIP_NETMASK0 << 8) | UIP_NETMASK1)) != |
| (uip_hostaddr[0] |
| & HTONS((UIP_NETMASK0 << 8) | UIP_NETMASK1))) |
| return; |
| if((IPBUF->srcipaddr[1] & HTONS((UIP_NETMASK2 << 8) | UIP_NETMASK3)) != |
| (uip_hostaddr[1] |
| & HTONS((UIP_NETMASK2 << 8) | UIP_NETMASK3))) |
| return; |
| */ |
| if((IPBUF->srcipaddr[0] & uip_arp_netmask[0]) != |
| (uip_hostaddr[0] & uip_arp_netmask[0])) { |
| return; |
| } |
| if((IPBUF->srcipaddr[1] & uip_arp_netmask[1]) != |
| (uip_hostaddr[1] & uip_arp_netmask[1])) { |
| return; |
| } |
| uip_arp_update(IPBUF->srcipaddr, &(IPBUF->ethhdr.src)); |
| |
| return; |
| } |
| /*-----------------------------------------------------------------------------------*/ |
| void |
| uip_arp_arpin(void) |
| { |
| |
| if(uip_len < sizeof(struct arp_hdr)) { |
| uip_len = 0; |
| return; |
| } |
| |
| uip_len = 0; |
| |
| switch(BUF->opcode) { |
| case HTONS(ARP_REQUEST): |
| /* ARP request. If it asked for our address, we send out a |
| reply. */ |
| if(BUF->dipaddr[0] == uip_hostaddr[0] && |
| BUF->dipaddr[1] == uip_hostaddr[1]) { |
| /* The reply opcode is 2. */ |
| BUF->opcode = HTONS(2); |
| |
| for(c = 0; c < 6; ++c) { |
| BUF->dhwaddr.addr[c] = BUF->shwaddr.addr[c]; |
| BUF->shwaddr.addr[c] = |
| BUF->ethhdr.src.addr[c] = uip_ethaddr.addr[c]; |
| BUF->ethhdr.dest.addr[c] = BUF->dhwaddr.addr[c]; |
| } |
| |
| BUF->dipaddr[0] = BUF->sipaddr[0]; |
| BUF->dipaddr[1] = BUF->sipaddr[1]; |
| BUF->sipaddr[0] = uip_hostaddr[0]; |
| BUF->sipaddr[1] = uip_hostaddr[1]; |
| |
| BUF->ethhdr.type = HTONS(UIP_ETHTYPE_ARP); |
| uip_len = sizeof(struct arp_hdr); |
| } |
| break; |
| case HTONS(ARP_REPLY): |
| /* ARP reply. We insert or update the ARP table if it was meant |
| for us. */ |
| if(BUF->dipaddr[0] == uip_hostaddr[0] && |
| BUF->dipaddr[1] == uip_hostaddr[1]) { |
| |
| uip_arp_update(BUF->sipaddr, &BUF->shwaddr); |
| } |
| break; |
| } |
| |
| return; |
| } |
| /*-----------------------------------------------------------------------------------*/ |
| void |
| uip_arp_out(void) |
| { |
| /* Find the destination IP address in the ARP table and construct |
| the Ethernet header. If the destination IP addres isn't on the |
| local network, we use the default router's IP address instead. |
| |
| If not ARP table entry is found, we overwrite the original IP |
| packet with an ARP request for the IP address. */ |
| |
| /* Check if the destination address is on the local network. */ |
| /* if((IPBUF->destipaddr[0] & HTONS((UIP_NETMASK0 << 8) | UIP_NETMASK1)) != |
| (uip_hostaddr[0] |
| & HTONS((UIP_NETMASK0 << 8) | UIP_NETMASK1)) || |
| (IPBUF->destipaddr[1] & HTONS((UIP_NETMASK2 << 8) | UIP_NETMASK3)) != |
| (uip_hostaddr[1] |
| & HTONS((UIP_NETMASK2 << 8) | UIP_NETMASK3))) {*/ |
| if((IPBUF->destipaddr[0] & uip_arp_netmask[0]) != |
| (uip_hostaddr[0] & uip_arp_netmask[0]) || |
| (IPBUF->destipaddr[1] & uip_arp_netmask[1]) != |
| (uip_hostaddr[1] & uip_arp_netmask[1])) { |
| /* Destination address was not on the local network, so we need to |
| use the default router's IP address instead of the destination |
| address when determining the MAC address. */ |
| /* ipaddr[0] = HTONS((UIP_DRIPADDR0 << 8) | UIP_DRIPADDR1); |
| ipaddr[1] = HTONS((UIP_DRIPADDR2 << 8) | UIP_DRIPADDR3);*/ |
| ipaddr[0] = uip_arp_draddr[0]; |
| ipaddr[1] = uip_arp_draddr[1]; |
| } else { |
| /* Else, we use the destination IP address. */ |
| ipaddr[0] = IPBUF->destipaddr[0]; |
| ipaddr[1] = IPBUF->destipaddr[1]; |
| } |
| |
| for(i = 0; i < UIP_ARPTAB_SIZE; ++i) { |
| if(ipaddr[0] == arp_table[i].ipaddr[0] && |
| ipaddr[1] == arp_table[i].ipaddr[1]) |
| break; |
| } |
| |
| if(i == UIP_ARPTAB_SIZE) { |
| /* The destination address was not in our ARP table, so we |
| overwrite the IP packet with an ARP request. */ |
| |
| for(c = 0; c < 6; ++c) { |
| BUF->ethhdr.dest.addr[c] = 0xff; /* Broadcast ARP request. */ |
| BUF->ethhdr.src.addr[c] = |
| BUF->shwaddr.addr[c] = uip_ethaddr.addr[c]; |
| BUF->dhwaddr.addr[c] = 0; |
| } |
| |
| BUF->dipaddr[0] = ipaddr[0]; |
| BUF->dipaddr[1] = ipaddr[1]; |
| BUF->sipaddr[0] = uip_hostaddr[0]; |
| BUF->sipaddr[1] = uip_hostaddr[1]; |
| BUF->opcode = HTONS(ARP_REQUEST); /* ARP request. */ |
| BUF->hwtype = HTONS(ARP_HWTYPE_ETH); |
| BUF->protocol = HTONS(UIP_ETHTYPE_IP); |
| BUF->hwlen = 6; |
| BUF->protolen = 4; |
| BUF->ethhdr.type = HTONS(UIP_ETHTYPE_ARP); |
| |
| uip_appdata = &uip_buf[40 + UIP_LLH_LEN]; |
| |
| uip_len = sizeof(struct arp_hdr); |
| return; |
| } |
| |
| /* Build an ethernet header. */ |
| for(c = 0; c < 6; ++c) { |
| IPBUF->ethhdr.dest.addr[c] = arp_table[i].ethaddr.addr[c]; |
| IPBUF->ethhdr.src.addr[c] = uip_ethaddr.addr[c]; |
| } |
| IPBUF->ethhdr.type = HTONS(UIP_ETHTYPE_IP); |
| |
| uip_len += sizeof(struct uip_eth_hdr); |
| } |
| /*-----------------------------------------------------------------------------------*/ |
| |
| |
| |
| |