net/rarp.c

   1 /*
   2  * (C) Copyright 2000-2002
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <command.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 #ifndef CONFIG_NET_RETRY_COUNT
  18 #define TIMEOUT_COUNT 5 /* # of timeouts before giving up  */
  19 #else
  20 #define TIMEOUT_COUNT (CONFIG_NET_RETRY_COUNT)
  21 #endif
  22
  23 int rarp_try;
  24
  25 /*
  26  *      Handle a RARP received packet.
  27  */
  28 void rarp_receive(struct ip_udp_hdr *ip, unsigned len)
  29 {
  30         struct arp_hdr *arp;
  31
  32         debug_cond(DEBUG_NET_PKT, "Got RARP\n");
  33         arp = (struct arp_hdr *)ip;
  34         if (len < ARP_HDR_SIZE) {
  35                 printf("bad length %d < %d\n", len, ARP_HDR_SIZE);
  36                 return;
  37         }
  38
  39         if ((ntohs(arp->ar_op) != RARPOP_REPLY) ||
  40             (ntohs(arp->ar_hrd) != ARP_ETHER)   ||
  41             (ntohs(arp->ar_pro) != PROT_IP)     ||
  42             (arp->ar_hln != 6) || (arp->ar_pln != 4)) {
  43                 puts("invalid RARP header\n");
  44         } else {
  45                 net_copy_ip(&net_ip, &arp->ar_data[16]);
  46                 if (net_server_ip.s_addr == 0)
  47                         net_copy_ip(&net_server_ip, &arp->ar_data[6]);
  48                 memcpy(net_server_ethaddr, &arp->ar_data[0], 6);
  49                 debug_cond(DEBUG_DEV_PKT, "Got good RARP\n");
  50                 net_auto_load();
  51         }
  52 }
  53
  54
  55 /*
  56  *      Timeout on BOOTP request.
  57  */
  58 static void rarp_timeout_handler(void)
  59 {
  60         if (rarp_try >= TIMEOUT_COUNT) {
  61                 puts("\nRetry count exceeded; starting again\n");
  62                 net_start_again();
  63         } else {
  64                 net_set_timeout_handler(TIMEOUT, rarp_timeout_handler);
  65                 rarp_request();
  66         }
  67 }
  68
  69
  70 void rarp_request(void)
  71 {
  72         uchar *pkt;
  73         struct arp_hdr *rarp;
  74         int eth_hdr_size;
  75
  76         printf("RARP broadcast %d\n", ++rarp_try);
  77         pkt = net_tx_packet;
  78
  79         eth_hdr_size = net_set_ether(pkt, net_bcast_ethaddr, PROT_RARP);
  80         pkt += eth_hdr_size;
  81
  82         rarp = (struct arp_hdr *)pkt;
  83
  84         rarp->ar_hrd = htons(ARP_ETHER);
  85         rarp->ar_pro = htons(PROT_IP);
  86         rarp->ar_hln = 6;
  87         rarp->ar_pln = 4;
  88         rarp->ar_op  = htons(RARPOP_REQUEST);
  89         memcpy(&rarp->ar_data[0],  net_ethaddr, 6);     /* source ET addr */
  90         memcpy(&rarp->ar_data[6],  &net_ip,   4);       /* source IP addr */
  91         /* dest ET addr = source ET addr ??*/
  92         memcpy(&rarp->ar_data[10], net_ethaddr, 6);
  93         /* dest IP addr set to broadcast */
  94         memset(&rarp->ar_data[16], 0xff,        4);
  95
  96         net_send_packet(net_tx_packet, eth_hdr_size + ARP_HDR_SIZE);
  97
  98         net_set_timeout_handler(TIMEOUT, rarp_timeout_handler);
  99 }