[zbin] Fix check for existence of most recent output byte
[ipxe.git] / src / net / rarp.c
1 /*
2 * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA.
18 */
19
20 FILE_LICENCE ( GPL2_OR_LATER );
21
22 #include <stdint.h>
23 #include <byteswap.h>
24 #include <ipxe/netdevice.h>
25 #include <ipxe/iobuf.h>
26 #include <ipxe/if_ether.h>
27 #include <ipxe/rarp.h>
28
29 /** @file
30 *
31 * Reverse Address Resolution Protocol
32 *
33 */
34
35 /**
36 * Process incoming ARP packets
37 *
38 * @v iobuf I/O buffer
39 * @v netdev Network device
40 * @v ll_dest Link-layer destination address
41 * @v ll_source Link-layer source address
42 * @v flags Packet flags
43 * @ret rc Return status code
44 *
45 * This is a dummy method which simply discards RARP packets.
46 */
47 static int rarp_rx ( struct io_buffer *iobuf,
48 struct net_device *netdev __unused,
49 const void *ll_dest __unused,
50 const void *ll_source __unused,
51 unsigned int flags __unused ) {
52 free_iob ( iobuf );
53 return 0;
54 }
55
56
57 /**
58 * Transcribe RARP address
59 *
60 * @v net_addr RARP address
61 * @ret string "<RARP>"
62 *
63 * This operation is meaningless for the RARP protocol.
64 */
65 static const char * rarp_ntoa ( const void *net_addr __unused ) {
66 return "<RARP>";
67 }
68
69 /** RARP protocol */
70 struct net_protocol rarp_protocol __net_protocol = {
71 .name = "RARP",
72 .net_proto = htons ( ETH_P_RARP ),
73 .rx = rarp_rx,
74 .ntoa = rarp_ntoa,
75 };