xref: /openbmc/u-boot/net/rarp.c (revision 4a2b2724)
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 }
100