Subversion Repositories openarty

////////////////////////////////////////////////////////////////////////////////

//

// Filename:    arp.c

//

// Project:     OpenArty, an entirely open SoC based upon the Arty platform

//

// Purpose:     To encapsulate common functions associated with the ARP protocol

//              and hardware (ethernet MAC) address resolution.

//

//

// Creator:     Dan Gisselquist, Ph.D.

//              Gisselquist Technology, LLC

//

////////////////////////////////////////////////////////////////////////////////

//

// Copyright (C) 2015-2016, Gisselquist Technology, LLC

//

// This program is free software (firmware): 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.

//

// This program is distributed in the hope that it will be useful, but WITHOUT

// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY 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 this program.  (It's in the $(ROOT)/doc directory, run make with no

// target there if the PDF file isn't present.)  If not, see

// <http://www.gnu.org/licenses/> for a copy.

//

// License:     GPL, v3, as defined and found on www.gnu.org,

//              http://www.gnu.org/licenses/gpl.html

//

//

////////////////////////////////////////////////////////////////////////////////

//

//

#include "zipcpu.h"

#include "zipsys.h"

#define KTRAPID_SENDPKT 0

#include "artyboard.h"

#include "etcnet.h"

#include "protoconst.h"

#include "ipcksum.h"

///////////

//

//

// Simplified ARP table and ARP requester

//

//

///////////

typedef struct  {

        int             valid;

        unsigned        age, ipaddr;

        unsigned long   mac;

} ARP_TABLE_ENTRY;

#define NUM_ARP_ENTRIES 8

ARP_TABLE_ENTRY arp_table[NUM_ARP_ENTRIES];

void    init_arp_table(void) {

        for(int k=0; k<NUM_ARP_ENTRIES; k++)

                arp_table[k].valid = 0;

}

int     get_next_arp_index(void) {

        int     eid, eldest = 0, unused_id = -1, oldage = 0, found=-1;

        for(eid=0; eid<NUM_ARP_ENTRIES; eid++) {

                if (!arp_table[eid].valid) {

                        unused_id = eid;

                        break;

                } else if (arp_table[eid].age > oldage) {

                        oldage = arp_table[eid].age;

                        eldest = eid;

                }

        }

        if (unused_id >= 0)

                return unused_id;

        return eldest;

}

void    send_arp_request(int ipaddr) {

        unsigned        pkt[9];

        pkt[0] = 0xffffffff;

        pkt[1] = 0xffff0000 | ETHERTYPE_ARP;

        pkt[2] = 0x010800;      // hardware type (enet), proto type (inet)

        pkt[3] = 0x06040001;    // 6 octets in enet addr, 4 in inet addr,request

        pkt[4] = (unsigned)(my_mac_addr>>16);

        pkt[5] = ((unsigned)(my_mac_addr<<16))|(my_ip_addr>>16);

        pkt[6] = (my_ip_addr<<16);

        pkt[7] = 0;

        pkt[8] = ipaddr;

        // Send our packet

        syscall(KTRAPID_SENDPKT,0,(unsigned)pkt, 9*4);

}

int     arp_lookup(unsigned ipaddr, unsigned long *mac) {

        int     eid, eldest = 0, unused_id = -1, oldage = 0, found=-1;

        if (((((ipaddr ^ my_ip_addr) & my_ip_mask) != 0)

                || (ipaddr == my_ip_router))

                        &&(router_mac_addr)) {

                *mac = router_mac_addr;

                return 0;

        }

        for(eid=0; eid<NUM_ARP_ENTRIES; eid++) {

                if (arp_table[eid].valid) {

                        if (arp_table[eid].ipaddr == ipaddr) {

                                arp_table[eid].age = 0;

                                *mac = arp_table[eid].mac;

                                return 0;

                        } else if (arp_table[eid].age > oldage) {

                                oldage = arp_table[eid].age++;

                                eldest = eid;

                                if (oldage >= 0x010000)

                                        arp_table[eid].valid = 0;

                        } else

                                arp_table[eid].age++;

                }

        }

        send_arp_request(ipaddr);

        return 1;

}

typedef struct  {

        unsigned ipaddr;

        unsigned long   mac;

} ARP_TABLE_LOG_ENTRY;

int     arp_logid = 0;

ARP_TABLE_LOG_ENTRY     arp_table_log[32];

void    arp_table_add(unsigned ipaddr, unsigned long mac) {

        unsigned long   lclmac;

        int             eid;

        arp_table_log[arp_logid].ipaddr = ipaddr;

        arp_table_log[arp_logid].mac = mac;

        arp_logid++;

        arp_logid&= 31;

        if (ipaddr == my_ip_addr)

                return;

        // Missing the 'if'??

        else if (ipaddr == my_ip_router) {

                router_mac_addr = mac;

        } else if (arp_lookup(ipaddr, &lclmac)==0) {

                if (mac != lclmac) {

                        for(eid=0; eid<NUM_ARP_ENTRIES; eid++) {

                                if ((arp_table[eid].valid)&&

                                        (arp_table[eid].ipaddr == ipaddr)) {

                                        volatile int *ev = &arp_table[eid].valid;

                                        // Prevent anyone from using an invalid

                                        // entry while we are updating it

                                        *ev = 0;

                                        arp_table[eid].age = 0;

                                        arp_table[eid].mac = mac;

                                        *ev = 1;

                                        break;

                                }

                        }

                }

        } else {

                volatile int *ev = &arp_table[eid].valid;

                eid = get_next_arp_index();

                // Prevent anyone from using an invalid entry while we are

                // updating it

                *ev = 0;

                arp_table[eid].age = 0;

                arp_table[eid].ipaddr = ipaddr;

                arp_table[eid].mac = mac;

                *ev = 1;

        }

}

void    send_arp_reply(unsigned machi, unsigned maclo, unsigned ipaddr) {

        unsigned pkt[9];

        pkt[0] = (machi<<16)|(maclo>>16);

        pkt[1] = (maclo<<16)|ETHERTYPE_ARP;

        pkt[2] = 0x010800;      // hardware type (enet), proto type (inet)

        pkt[3] = 0x06040002;

        pkt[4] = (unsigned)(my_mac_addr>>16);

        pkt[5] = ((unsigned)(my_mac_addr<<16))|(my_ip_addr>>16);

        pkt[6] = (my_ip_addr<<16)|(machi);

        pkt[7] = maclo;

        pkt[8] = ipaddr;

        syscall(KTRAPID_SENDPKT, 0, (int)pkt, 9*4);

}