net/arp.c

   1 /*
   2  *      Copied from Linux Monitor (LiMon) - Networking.
   3  *
   4  *      Copyright 1994 - 2000 Neil Russell.
   5  *      (See License)
   6  *      Copyright 2000 Roland Borde
   7  *      Copyright 2000 Paolo Scaffardi
   8  *      Copyright 2000-2002 Wolfgang Denk, wd@denx.de
   9  */
  10
  11 #include <common.h>
  12
  13 #include "arp.h"
  14
  15 #ifndef CONFIG_ARP_TIMEOUT
  16 /* Milliseconds before trying ARP again */
  17 # define ARP_TIMEOUT            5000UL
  18 #else
  19 # define ARP_TIMEOUT            CONFIG_ARP_TIMEOUT
  20 #endif
  21
  22
  23 #ifndef CONFIG_NET_RETRY_COUNT
  24 # define ARP_TIMEOUT_COUNT      5       /* # of timeouts before giving up  */
  25 #else
  26 # define ARP_TIMEOUT_COUNT      CONFIG_NET_RETRY_COUNT
  27 #endif
  28
  29 IPaddr_t        NetArpWaitPacketIP;
  30 static IPaddr_t NetArpWaitReplyIP;
  31 /* MAC address of waiting packet's destination */
  32 uchar          *NetArpWaitPacketMAC;
  33 int             NetArpWaitTxPacketSize;
  34 ulong           NetArpWaitTimerStart;
  35 int             NetArpWaitTry;
  36
  37 static uchar   *NetArpTxPacket; /* THE ARP transmit packet */
  38 static uchar    NetArpPacketBuf[PKTSIZE_ALIGN + PKTALIGN];
  39
  40 void ArpInit(void)
  41 {
  42         /* XXX problem with bss workaround */
  43         NetArpWaitPacketMAC = NULL;
  44         NetArpWaitPacketIP = 0;
  45         NetArpWaitReplyIP = 0;
  46         NetArpWaitTxPacketSize = 0;
  47         NetArpTxPacket = &NetArpPacketBuf[0] + (PKTALIGN - 1);
  48         NetArpTxPacket -= (ulong)NetArpTxPacket % PKTALIGN;
  49 }
  50
  51 void arp_raw_request(IPaddr_t sourceIP, const uchar *targetEther,
  52         IPaddr_t targetIP)
  53 {
  54         uchar *pkt;
  55         struct arp_hdr *arp;
  56         int eth_hdr_size;
  57
  58         debug_cond(DEBUG_DEV_PKT, "ARP broadcast %d\n", NetArpWaitTry);
  59
  60         pkt = NetArpTxPacket;
  61
  62         eth_hdr_size = NetSetEther(pkt, NetBcastAddr, PROT_ARP);
  63         pkt += eth_hdr_size;
  64
  65         arp = (struct arp_hdr *) pkt;
  66
  67         arp->ar_hrd = htons(ARP_ETHER);
  68         arp->ar_pro = htons(PROT_IP);
  69         arp->ar_hln = ARP_HLEN;
  70         arp->ar_pln = ARP_PLEN;
  71         arp->ar_op = htons(ARPOP_REQUEST);
  72
  73         memcpy(&arp->ar_sha, NetOurEther, ARP_HLEN);    /* source ET addr */
  74         NetWriteIP(&arp->ar_spa, sourceIP);             /* source IP addr */
  75         memcpy(&arp->ar_tha, targetEther, ARP_HLEN);    /* target ET addr */
  76         NetWriteIP(&arp->ar_tpa, targetIP);             /* target IP addr */
  77
  78         NetSendPacket(NetArpTxPacket, eth_hdr_size + ARP_HDR_SIZE);
  79 }
  80
  81 void ArpRequest(void)
  82 {
  83         if ((NetArpWaitPacketIP & NetOurSubnetMask) !=
  84             (NetOurIP & NetOurSubnetMask)) {
  85                 if (NetOurGatewayIP == 0) {
  86                         puts("## Warning: gatewayip needed but not set\n");
  87                         NetArpWaitReplyIP = NetArpWaitPacketIP;
  88                 } else {
  89                         NetArpWaitReplyIP = NetOurGatewayIP;
  90                 }
  91         } else {
  92                 NetArpWaitReplyIP = NetArpWaitPacketIP;
  93         }
  94
  95         arp_raw_request(NetOurIP, NetEtherNullAddr, NetArpWaitReplyIP);
  96 }
  97
  98 void ArpTimeoutCheck(void)
  99 {
 100         ulong t;
 101
 102         if (!NetArpWaitPacketIP)
 103                 return;
 104
 105         t = get_timer(0);
 106
 107         /* check for arp timeout */
 108         if ((t - NetArpWaitTimerStart) > ARP_TIMEOUT) {
 109                 NetArpWaitTry++;
 110
 111                 if (NetArpWaitTry >= ARP_TIMEOUT_COUNT) {
 112                         puts("\nARP Retry count exceeded; starting again\n");
 113                         NetArpWaitTry = 0;
 114                         NetStartAgain();
 115                 } else {
 116                         NetArpWaitTimerStart = t;
 117                         ArpRequest();
 118                 }
 119         }
 120 }
 121
 122 void ArpReceive(struct ethernet_hdr *et, struct ip_udp_hdr *ip, int len)
 123 {
 124         struct arp_hdr *arp;
 125         IPaddr_t reply_ip_addr;
 126         uchar *pkt;
 127         int eth_hdr_size;
 128
 129         /*
 130          * We have to deal with two types of ARP packets:
 131          * - REQUEST packets will be answered by sending  our
 132          *   IP address - if we know it.
 133          * - REPLY packates are expected only after we asked
 134          *   for the TFTP server's or the gateway's ethernet
 135          *   address; so if we receive such a packet, we set
 136          *   the server ethernet address
 137          */
 138         debug_cond(DEBUG_NET_PKT, "Got ARP\n");
 139
 140         arp = (struct arp_hdr *)ip;
 141         if (len < ARP_HDR_SIZE) {
 142                 printf("bad length %d < %d\n", len, ARP_HDR_SIZE);
 143                 return;
 144         }
 145         if (ntohs(arp->ar_hrd) != ARP_ETHER)
 146                 return;
 147         if (ntohs(arp->ar_pro) != PROT_IP)
 148                 return;
 149         if (arp->ar_hln != ARP_HLEN)
 150                 return;
 151         if (arp->ar_pln != ARP_PLEN)
 152                 return;
 153
 154         if (NetOurIP == 0)
 155                 return;
 156
 157         if (NetReadIP(&arp->ar_tpa) != NetOurIP)
 158                 return;
 159
 160         switch (ntohs(arp->ar_op)) {
 161         case ARPOP_REQUEST:
 162                 /* reply with our IP address */
 163                 debug_cond(DEBUG_DEV_PKT, "Got ARP REQUEST, return our IP\n");
 164                 pkt = (uchar *)et;
 165                 eth_hdr_size = net_update_ether(et, et->et_src, PROT_ARP);
 166                 pkt += eth_hdr_size;
 167                 arp->ar_op = htons(ARPOP_REPLY);
 168                 memcpy(&arp->ar_tha, &arp->ar_sha, ARP_HLEN);
 169                 NetCopyIP(&arp->ar_tpa, &arp->ar_spa);
 170                 memcpy(&arp->ar_sha, NetOurEther, ARP_HLEN);
 171                 NetCopyIP(&arp->ar_spa, &NetOurIP);
 172
 173 #ifdef CONFIG_CMD_LINK_LOCAL
 174                 /*
 175                  * Work-around for brain-damaged Cisco equipment with
 176                  *   arp-proxy enabled.
 177                  *
 178                  *   If the requesting IP is not on our subnet, wait 5ms to
 179                  *   reply to ARP request so that our reply will overwrite
 180                  *   the arp-proxy's instead of the other way around.
 181                  */
 182                 if ((NetReadIP(&arp->ar_tpa) & NetOurSubnetMask) !=
 183                     (NetReadIP(&arp->ar_spa) & NetOurSubnetMask))
 184                         udelay(5000);
 185 #endif
 186                 NetSendPacket((uchar *)et, eth_hdr_size + ARP_HDR_SIZE);
 187                 return;
 188
 189         case ARPOP_REPLY:               /* arp reply */
 190                 /* are we waiting for a reply */
 191                 if (!NetArpWaitPacketIP)
 192                         break;
 193
 194 #ifdef CONFIG_KEEP_SERVERADDR
 195                 if (NetServerIP == NetArpWaitPacketIP) {
 196                         char buf[20];
 197                         sprintf(buf, "%pM", &arp->ar_sha);
 198                         setenv("serveraddr", buf);
 199                 }
 200 #endif
 201
 202                 reply_ip_addr = NetReadIP(&arp->ar_spa);
 203
 204                 /* matched waiting packet's address */
 205                 if (reply_ip_addr == NetArpWaitReplyIP) {
 206                         debug_cond(DEBUG_DEV_PKT,
 207                                 "Got ARP REPLY, set eth addr (%pM)\n",
 208                                 arp->ar_data);
 209
 210                         /* save address for later use */
 211                         if (NetArpWaitPacketMAC != NULL)
 212                                 memcpy(NetArpWaitPacketMAC,
 213                                        &arp->ar_sha, ARP_HLEN);
 214
 215                         net_get_arp_handler()((uchar *)arp, 0, reply_ip_addr,
 216                                 0, len);
 217
 218                         /* set the mac address in the waiting packet's header
 219                            and transmit it */
 220                         memcpy(((struct ethernet_hdr *)NetTxPacket)->et_dest,
 221                                 &arp->ar_sha, ARP_HLEN);
 222                         NetSendPacket(NetTxPacket, NetArpWaitTxPacketSize);
 223
 224                         /* no arp request pending now */
 225                         NetArpWaitPacketIP = 0;
 226                         NetArpWaitTxPacketSize = 0;
 227                         NetArpWaitPacketMAC = NULL;
 228
 229                 }
 230                 return;
 231         default:
 232                 debug("Unexpected ARP opcode 0x%x\n",
 233                       ntohs(arp->ar_op));
 234                 return;
 235         }
 236 }