1 /*
2 * Copyright (C) 2009 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., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 FILE_LICENCE ( GPL2_OR_LATER );
20
21 #include <string.h>
22 #include <errno.h>
23 #include <gpxe/iobuf.h>
24 #include <gpxe/in.h>
25 #include <gpxe/tcpip.h>
26 #include <gpxe/icmp.h>
27
28 /** @file
29 *
30 * ICMP protocol
31 *
32 */
33
34 struct tcpip_protocol icmp_protocol __tcpip_protocol;
35
36 /**
37 * Process a received packet
38 *
39 * @v iobuf I/O buffer
40 * @v st_src Partially-filled source address
41 * @v st_dest Partially-filled destination address
42 * @v pshdr_csum Pseudo-header checksum
43 * @ret rc Return status code
44 */
icmp_rx(struct io_buffer * iobuf,struct sockaddr_tcpip * st_src,struct sockaddr_tcpip * st_dest,uint16_t pshdr_csum __unused)45 static int icmp_rx ( struct io_buffer *iobuf, struct sockaddr_tcpip *st_src,
46 struct sockaddr_tcpip *st_dest,
47 uint16_t pshdr_csum __unused ) {
48 struct icmp_header *icmp = iobuf->data;
49 size_t len = iob_len ( iobuf );
50 unsigned int csum;
51 int rc;
52
53 /* Sanity check */
54 if ( len < sizeof ( *icmp ) ) {
55 DBG ( "ICMP packet too short at %zd bytes (min %zd bytes)\n",
56 len, sizeof ( *icmp ) );
57 rc = -EINVAL;
58 goto done;
59 }
60
61 /* Verify checksum */
62 csum = tcpip_chksum ( icmp, len );
63 if ( csum != 0 ) {
64 DBG ( "ICMP checksum incorrect (is %04x, should be 0000)\n",
65 csum );
66 DBG_HD ( icmp, len );
67 rc = -EINVAL;
68 goto done;
69 }
70
71 /* We respond only to pings */
72 if ( icmp->type != ICMP_ECHO_REQUEST ) {
73 DBG ( "ICMP ignoring type %d\n", icmp->type );
74 rc = 0;
75 goto done;
76 }
77
78 DBG ( "ICMP responding to ping\n" );
79
80 /* Change type to response and recalculate checksum */
81 icmp->type = ICMP_ECHO_RESPONSE;
82 icmp->chksum = 0;
83 icmp->chksum = tcpip_chksum ( icmp, len );
84
85 /* Transmit the response */
86 if ( ( rc = tcpip_tx ( iob_disown ( iobuf ), &icmp_protocol, st_dest,
87 st_src, NULL, NULL ) ) != 0 ) {
88 DBG ( "ICMP could not transmit ping response: %s\n",
89 strerror ( rc ) );
90 goto done;
91 }
92
93 done:
94 free_iob ( iobuf );
95 return rc;
96 }
97
98 /** ICMP TCP/IP protocol */
99 struct tcpip_protocol icmp_protocol __tcpip_protocol = {
100 .name = "ICMP",
101 .rx = icmp_rx,
102 .tcpip_proto = IP_ICMP,
103 };
104