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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  *      SPDX-License-Identifier:        GPL-2.0
10  */
11
12 #include <common.h>
13
14 #include "arp.h"
15
16 #ifndef CONFIG_ARP_TIMEOUT
17 /* Milliseconds before trying ARP again */
18 # define ARP_TIMEOUT            5000UL
19 #else
20 # define ARP_TIMEOUT            CONFIG_ARP_TIMEOUT
21 #endif
22
23
24 #ifndef CONFIG_NET_RETRY_COUNT
25 # define ARP_TIMEOUT_COUNT      5       /* # of timeouts before giving up  */
26 #else
27 # define ARP_TIMEOUT_COUNT      CONFIG_NET_RETRY_COUNT
28 #endif
29
30 struct in_addr net_arp_wait_packet_ip;
31 static struct in_addr net_arp_wait_reply_ip;
32 /* MAC address of waiting packet's destination */
33 uchar          *arp_wait_packet_ethaddr;
34 int             arp_wait_tx_packet_size;
35 ulong           arp_wait_timer_start;
36 int             arp_wait_try;
37
38 static uchar   *arp_tx_packet;  /* THE ARP transmit packet */
39 static uchar    arp_tx_packet_buf[PKTSIZE_ALIGN + PKTALIGN];
40
41 void arp_init(void)
42 {
43         /* XXX problem with bss workaround */
44         arp_wait_packet_ethaddr = NULL;
45         net_arp_wait_packet_ip.s_addr = 0;
46         net_arp_wait_reply_ip.s_addr = 0;
47         arp_wait_tx_packet_size = 0;
48         arp_tx_packet = &arp_tx_packet_buf[0] + (PKTALIGN - 1);
49         arp_tx_packet -= (ulong)arp_tx_packet % PKTALIGN;
50 }
51
52 void arp_raw_request(struct in_addr source_ip, const uchar *target_ethaddr,
53         struct in_addr target_ip)
54 {
55         uchar *pkt;
56         struct arp_hdr *arp;
57         int eth_hdr_size;
58
59         debug_cond(DEBUG_DEV_PKT, "ARP broadcast %d\n", arp_wait_try);
60
61         pkt = arp_tx_packet;
62
63         eth_hdr_size = net_set_ether(pkt, net_bcast_ethaddr, PROT_ARP);
64         pkt += eth_hdr_size;
65
66         arp = (struct arp_hdr *)pkt;
67
68         arp->ar_hrd = htons(ARP_ETHER);
69         arp->ar_pro = htons(PROT_IP);
70         arp->ar_hln = ARP_HLEN;
71         arp->ar_pln = ARP_PLEN;
72         arp->ar_op = htons(ARPOP_REQUEST);
73
74         memcpy(&arp->ar_sha, net_ethaddr, ARP_HLEN);    /* source ET addr */
75         net_write_ip(&arp->ar_spa, source_ip);          /* source IP addr */
76         memcpy(&arp->ar_tha, target_ethaddr, ARP_HLEN); /* target ET addr */
77         net_write_ip(&arp->ar_tpa, target_ip);          /* target IP addr */
78
79         net_send_packet(arp_tx_packet, eth_hdr_size + ARP_HDR_SIZE);
80 }
81
82 void arp_request(void)
83 {
84         if ((net_arp_wait_packet_ip.s_addr & net_netmask.s_addr) !=
85             (net_ip.s_addr & net_netmask.s_addr)) {
86                 if (net_gateway.s_addr == 0) {
87                         puts("## Warning: gatewayip needed but not set\n");
88                         net_arp_wait_reply_ip = net_arp_wait_packet_ip;
89                 } else {
90                         net_arp_wait_reply_ip = net_gateway;
91                 }
92         } else {
93                 net_arp_wait_reply_ip = net_arp_wait_packet_ip;
94         }
95
96         arp_raw_request(net_ip, net_null_ethaddr, net_arp_wait_reply_ip);
97 }
98
99 int arp_timeout_check(void)
100 {
101         ulong t;
102
103         if (!net_arp_wait_packet_ip.s_addr)
104                 return 0;
105
106         t = get_timer(0);
107
108         /* check for arp timeout */
109         if ((t - arp_wait_timer_start) > ARP_TIMEOUT) {
110                 arp_wait_try++;
111
112                 if (arp_wait_try >= ARP_TIMEOUT_COUNT) {
113                         puts("\nARP Retry count exceeded; starting again\n");
114                         arp_wait_try = 0;
115                         net_set_state(NETLOOP_FAIL);
116                 } else {
117                         arp_wait_timer_start = t;
118                         arp_request();
119                 }
120         }
121         return 1;
122 }
123
124 void arp_receive(struct ethernet_hdr *et, struct ip_udp_hdr *ip, int len)
125 {
126         struct arp_hdr *arp;
127         struct in_addr reply_ip_addr;
128         uchar *pkt;
129         int eth_hdr_size;
130
131         /*
132          * We have to deal with two types of ARP packets:
133          * - REQUEST packets will be answered by sending  our
134          *   IP address - if we know it.
135          * - REPLY packates are expected only after we asked
136          *   for the TFTP server's or the gateway's ethernet
137          *   address; so if we receive such a packet, we set
138          *   the server ethernet address
139          */
140         debug_cond(DEBUG_NET_PKT, "Got ARP\n");
141
142         arp = (struct arp_hdr *)ip;
143         if (len < ARP_HDR_SIZE) {
144                 printf("bad length %d < %d\n", len, ARP_HDR_SIZE);
145                 return;
146         }
147         if (ntohs(arp->ar_hrd) != ARP_ETHER)
148                 return;
149         if (ntohs(arp->ar_pro) != PROT_IP)
150                 return;
151         if (arp->ar_hln != ARP_HLEN)
152                 return;
153         if (arp->ar_pln != ARP_PLEN)
154                 return;
155
156         if (net_ip.s_addr == 0)
157                 return;
158
159         if (net_read_ip(&arp->ar_tpa).s_addr != net_ip.s_addr)
160                 return;
161
162         switch (ntohs(arp->ar_op)) {
163         case ARPOP_REQUEST:
164                 /* reply with our IP address */
165                 debug_cond(DEBUG_DEV_PKT, "Got ARP REQUEST, return our IP\n");
166                 pkt = (uchar *)et;
167                 eth_hdr_size = net_update_ether(et, et->et_src, PROT_ARP);
168                 pkt += eth_hdr_size;
169                 arp->ar_op = htons(ARPOP_REPLY);
170                 memcpy(&arp->ar_tha, &arp->ar_sha, ARP_HLEN);
171                 net_copy_ip(&arp->ar_tpa, &arp->ar_spa);
172                 memcpy(&arp->ar_sha, net_ethaddr, ARP_HLEN);
173                 net_copy_ip(&arp->ar_spa, &net_ip);
174
175 #ifdef CONFIG_CMD_LINK_LOCAL
176                 /*
177                  * Work-around for brain-damaged Cisco equipment with
178                  *   arp-proxy enabled.
179                  *
180                  *   If the requesting IP is not on our subnet, wait 5ms to
181                  *   reply to ARP request so that our reply will overwrite
182                  *   the arp-proxy's instead of the other way around.
183                  */
184                 if ((net_read_ip(&arp->ar_tpa).s_addr & net_netmask.s_addr) !=
185                     (net_read_ip(&arp->ar_spa).s_addr & net_netmask.s_addr))
186                         udelay(5000);
187 #endif
188                 net_send_packet((uchar *)et, eth_hdr_size + ARP_HDR_SIZE);
189                 return;
190
191         case ARPOP_REPLY:               /* arp reply */
192                 /* are we waiting for a reply */
193                 if (!net_arp_wait_packet_ip.s_addr)
194                         break;
195
196 #ifdef CONFIG_KEEP_SERVERADDR
197                 if (net_server_ip.s_addr == net_arp_wait_packet_ip.s_addr) {
198                         char buf[20];
199                         sprintf(buf, "%pM", &arp->ar_sha);
200                         setenv("serveraddr", buf);
201                 }
202 #endif
203
204                 reply_ip_addr = net_read_ip(&arp->ar_spa);
205
206                 /* matched waiting packet's address */
207                 if (reply_ip_addr.s_addr == net_arp_wait_reply_ip.s_addr) {
208                         debug_cond(DEBUG_DEV_PKT,
209                                    "Got ARP REPLY, set eth addr (%pM)\n",
210                                    arp->ar_data);
211
212                         /* save address for later use */
213                         if (arp_wait_packet_ethaddr != NULL)
214                                 memcpy(arp_wait_packet_ethaddr,
215                                        &arp->ar_sha, ARP_HLEN);
216
217                         net_get_arp_handler()((uchar *)arp, 0, reply_ip_addr,
218                                               0, len);
219
220                         /* set the mac address in the waiting packet's header
221                            and transmit it */
222                         memcpy(((struct ethernet_hdr *)net_tx_packet)->et_dest,
223                                &arp->ar_sha, ARP_HLEN);
224                         net_send_packet(net_tx_packet, arp_wait_tx_packet_size);
225
226                         /* no arp request pending now */
227                         net_arp_wait_packet_ip.s_addr = 0;
228                         arp_wait_tx_packet_size = 0;
229                         arp_wait_packet_ethaddr = NULL;
230                 }
231                 return;
232         default:
233                 debug("Unexpected ARP opcode 0x%x\n",
234                       ntohs(arp->ar_op));
235                 return;
236         }
237 }