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      1 // SPDX-License-Identifier: GPL-2.0+
      2 /*
      3  * (C) Copyright 2000-2002
      4  * Wolfgang Denk, DENX Software Engineering, wd (at) denx.de.
      5  */
      6 
      7 #include <common.h>
      8 #include <command.h>
      9 #include <net.h>
     10 #include <net/tftp.h>
     11 #include "nfs.h"
     12 #include "bootp.h"
     13 #include "rarp.h"
     14 
     15 #define TIMEOUT 5000UL /* Milliseconds before trying BOOTP again */
     16 #ifndef	CONFIG_NET_RETRY_COUNT
     17 #define TIMEOUT_COUNT 5 /* # of timeouts before giving up  */
     18 #else
     19 #define TIMEOUT_COUNT (CONFIG_NET_RETRY_COUNT)
     20 #endif
     21 
     22 int rarp_try;
     23 
     24 /*
     25  *	Handle a RARP received packet.
     26  */
     27 void rarp_receive(struct ip_udp_hdr *ip, unsigned len)
     28 {
     29 	struct arp_hdr *arp;
     30 
     31 	debug_cond(DEBUG_NET_PKT, "Got RARP\n");
     32 	arp = (struct arp_hdr *)ip;
     33 	if (len < ARP_HDR_SIZE) {
     34 		printf("bad length %d < %d\n", len, ARP_HDR_SIZE);
     35 		return;
     36 	}
     37 
     38 	if ((ntohs(arp->ar_op) != RARPOP_REPLY) ||
     39 	    (ntohs(arp->ar_hrd) != ARP_ETHER)   ||
     40 	    (ntohs(arp->ar_pro) != PROT_IP)     ||
     41 	    (arp->ar_hln != 6) || (arp->ar_pln != 4)) {
     42 		puts("invalid RARP header\n");
     43 	} else {
     44 		net_copy_ip(&net_ip, &arp->ar_data[16]);
     45 		if (net_server_ip.s_addr == 0)
     46 			net_copy_ip(&net_server_ip, &arp->ar_data[6]);
     47 		memcpy(net_server_ethaddr, &arp->ar_data[0], 6);
     48 		debug_cond(DEBUG_DEV_PKT, "Got good RARP\n");
     49 		net_auto_load();
     50 	}
     51 }
     52 
     53 
     54 /*
     55  *	Timeout on BOOTP request.
     56  */
     57 static void rarp_timeout_handler(void)
     58 {
     59 	if (rarp_try >= TIMEOUT_COUNT) {
     60 		puts("\nRetry count exceeded; starting again\n");
     61 		net_start_again();
     62 	} else {
     63 		net_set_timeout_handler(TIMEOUT, rarp_timeout_handler);
     64 		rarp_request();
     65 	}
     66 }
     67 
     68 
     69 void rarp_request(void)
     70 {
     71 	uchar *pkt;
     72 	struct arp_hdr *rarp;
     73 	int eth_hdr_size;
     74 
     75 	printf("RARP broadcast %d\n", ++rarp_try);
     76 	pkt = net_tx_packet;
     77 
     78 	eth_hdr_size = net_set_ether(pkt, net_bcast_ethaddr, PROT_RARP);
     79 	pkt += eth_hdr_size;
     80 
     81 	rarp = (struct arp_hdr *)pkt;
     82 
     83 	rarp->ar_hrd = htons(ARP_ETHER);
     84 	rarp->ar_pro = htons(PROT_IP);
     85 	rarp->ar_hln = 6;
     86 	rarp->ar_pln = 4;
     87 	rarp->ar_op  = htons(RARPOP_REQUEST);
     88 	memcpy(&rarp->ar_data[0],  net_ethaddr, 6);	/* source ET addr */
     89 	memcpy(&rarp->ar_data[6],  &net_ip,   4);	/* source IP addr */
     90 	/* dest ET addr = source ET addr ??*/
     91 	memcpy(&rarp->ar_data[10], net_ethaddr, 6);
     92 	/* dest IP addr set to broadcast */
     93 	memset(&rarp->ar_data[16], 0xff,        4);
     94 
     95 	net_send_packet(net_tx_packet, eth_hdr_size + ARP_HDR_SIZE);
     96 
     97 	net_set_timeout_handler(TIMEOUT, rarp_timeout_handler);
     98 }
     99