Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
[icmp] Add support for responding to pings
- Loading branch information
Michael Brown
committed
Feb 17, 2009
1 parent
dbbd81c
commit 06b5132
Showing
4 changed files
with
128 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,23 @@ | ||
#ifndef _GPXE_ICMP_H | ||
#define _GPXE_ICMP_H | ||
|
||
/** @file | ||
* | ||
* ICMP protocol | ||
* | ||
*/ | ||
|
||
/** An ICMP header */ | ||
struct icmp_header { | ||
/** Type */ | ||
uint8_t type; | ||
/** Code */ | ||
uint8_t code; | ||
/** Checksum */ | ||
uint16_t chksum; | ||
} __attribute__ (( packed )); | ||
|
||
#define ICMP_ECHO_RESPONSE 0 | ||
#define ICMP_ECHO_REQUEST 8 | ||
|
||
#endif /* _GPXE_ICMP_H */ |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,101 @@ | ||
/* | ||
* 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. | ||
*/ | ||
|
||
#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, | ||
}; |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters