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/*
* Copyright (C) 2009 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <string.h>
#include <errno.h>
#include <gpxe/iobuf.h>
#include <gpxe/in.h>
#include <gpxe/tcpip.h>
#include <gpxe/icmp.h>
/** @file
*
* ICMP protocol
*
*/
struct tcpip_protocol icmp_protocol __tcpip_protocol;
/**
* Process a received packet
*
* @v iobuf I/O buffer
* @v st_src Partially-filled source address
* @v st_dest Partially-filled destination address
* @v pshdr_csum Pseudo-header checksum
* @ret rc Return status code
*/
static int icmp_rx ( struct io_buffer *iobuf, struct sockaddr_tcpip *st_src,
struct sockaddr_tcpip *st_dest,
uint16_t pshdr_csum __unused ) {
struct icmp_header *icmp = iobuf->data;
size_t len = iob_len ( iobuf );
unsigned int csum;
int rc;
/* Sanity check */
if ( len < sizeof ( *icmp ) ) {
DBG ( "ICMP packet too short at %zd bytes (min %zd bytes)\n",
len, sizeof ( *icmp ) );
rc = -EINVAL;
goto done;
}
/* Verify checksum */
csum = tcpip_chksum ( icmp, len );
if ( csum != 0 ) {
DBG ( "ICMP checksum incorrect (is %04x, should be 0000)\n",
csum );
DBG_HD ( icmp, len );
rc = -EINVAL;
goto done;
}
/* We respond only to pings */
if ( icmp->type != ICMP_ECHO_REQUEST ) {
DBG ( "ICMP ignoring type %d\n", icmp->type );
rc = 0;
goto done;
}
DBG ( "ICMP responding to ping\n" );
/* Change type to response and recalculate checksum */
icmp->type = ICMP_ECHO_RESPONSE;
icmp->chksum = 0;
icmp->chksum = tcpip_chksum ( icmp, len );
/* Transmit the response */
if ( ( rc = tcpip_tx ( iob_disown ( iobuf ), &icmp_protocol, st_dest,
st_src, NULL, NULL ) ) != 0 ) {
DBG ( "ICMP could not transmit ping response: %s\n",
strerror ( rc ) );
goto done;
}
done:
free_iob ( iobuf );
return rc;
}
/** ICMP TCP/IP protocol */
struct tcpip_protocol icmp_protocol __tcpip_protocol = {
.name = "ICMP",
.rx = icmp_rx,
.tcpip_proto = IP_ICMP,
};
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