net/rarp.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * (C) Copyright 2000-2002
   4  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   5  */
   6
   7 #include <common.h>
   8 #include <command.h>
   9 #include <log.h>
  10 #include <net.h>
  11 #include <net/tftp.h>
  12 #include "nfs.h"
  13 #include "bootp.h"
  14 #include "rarp.h"
  15
  16 #define TIMEOUT 5000UL /* Milliseconds before trying BOOTP again */
  17
  18 int rarp_try;
  19
  20 /*
  21  *      Handle a RARP received packet.
  22  */
  23 void rarp_receive(struct ip_udp_hdr *ip, unsigned len)
  24 {
  25         struct arp_hdr *arp;
  26
  27         debug_cond(DEBUG_NET_PKT, "Got RARP\n");
  28         arp = (struct arp_hdr *)ip;
  29         if (len < ARP_HDR_SIZE) {
  30                 printf("bad length %d < %d\n", len, ARP_HDR_SIZE);
  31                 return;
  32         }
  33
  34         if ((ntohs(arp->ar_op) != RARPOP_REPLY) ||
  35             (ntohs(arp->ar_hrd) != ARP_ETHER)   ||
  36             (ntohs(arp->ar_pro) != PROT_IP)     ||
  37             (arp->ar_hln != 6) || (arp->ar_pln != 4)) {
  38                 puts("invalid RARP header\n");
  39         } else {
  40                 net_copy_ip(&net_ip, &arp->ar_data[16]);
  41                 if (net_server_ip.s_addr == 0)
  42                         net_copy_ip(&net_server_ip, &arp->ar_data[6]);
  43                 memcpy(net_server_ethaddr, &arp->ar_data[0], 6);
  44                 debug_cond(DEBUG_DEV_PKT, "Got good RARP\n");
  45                 net_auto_load();
  46         }
  47 }
  48
  49
  50 /*
  51  *      Timeout on BOOTP request.
  52  */
  53 static void rarp_timeout_handler(void)
  54 {
  55         if (rarp_try >= CONFIG_NET_RETRY_COUNT) {
  56                 puts("\nRetry count exceeded; starting again\n");
  57                 net_start_again();
  58         } else {
  59                 net_set_timeout_handler(TIMEOUT, rarp_timeout_handler);
  60                 rarp_request();
  61         }
  62 }
  63
  64
  65 void rarp_request(void)
  66 {
  67         uchar *pkt;
  68         struct arp_hdr *rarp;
  69         int eth_hdr_size;
  70
  71         printf("RARP broadcast %d\n", ++rarp_try);
  72         pkt = net_tx_packet;
  73
  74         eth_hdr_size = net_set_ether(pkt, net_bcast_ethaddr, PROT_RARP);
  75         pkt += eth_hdr_size;
  76
  77         rarp = (struct arp_hdr *)pkt;
  78
  79         rarp->ar_hrd = htons(ARP_ETHER);
  80         rarp->ar_pro = htons(PROT_IP);
  81         rarp->ar_hln = 6;
  82         rarp->ar_pln = 4;
  83         rarp->ar_op  = htons(RARPOP_REQUEST);
  84         memcpy(&rarp->ar_data[0],  net_ethaddr, 6);     /* source ET addr */
  85         memcpy(&rarp->ar_data[6],  &net_ip,   4);       /* source IP addr */
  86         /* dest ET addr = source ET addr ??*/
  87         memcpy(&rarp->ar_data[10], net_ethaddr, 6);
  88         /* dest IP addr set to broadcast */
  89         memset(&rarp->ar_data[16], 0xff,        4);
  90
  91         net_send_packet(net_tx_packet, eth_hdr_size + ARP_HDR_SIZE);
  92
  93         net_set_timeout_handler(TIMEOUT, rarp_timeout_handler);
  94 }