icmp.c File Reference

ICMP protocol. More...

#include <string.h>
#include <errno.h>
#include <gpxe/iobuf.h>
#include <gpxe/in.h>
#include <gpxe/tcpip.h>
#include <gpxe/icmp.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER)
static int	icmp_rx (struct io_buffer *iobuf, struct sockaddr_tcpip *st_src, struct sockaddr_tcpip *st_dest, uint16_t pshdr_csum __unused)
	Process a received packet.
Variables
struct tcpip_protocol icmp_protocol	__tcpip_protocol
	ICMP TCP/IP protocol.

---

Detailed Description

ICMP protocol.

Definition in file icmp.c.

---

Function Documentation

FILE_LICENCE

(

GPL2_OR_LATER

)

static int icmp_rx	(	struct io_buffer *	iobuf,
		struct sockaddr_tcpip *	st_src,
		struct sockaddr_tcpip *	st_dest,
		uint16_t pshdr_csum	__unused
	)			[static]

Process a received packet.

Parameters:

	iobuf	I/O buffer
	st_src	Partially-filled source address
	st_dest	Partially-filled destination address
	pshdr_csum	Pseudo-header checksum

Return values:

rc

Return status code

Definition at line 45 of file icmp.c.

References icmp_header::chksum, io_buffer::data, DBG, DBG_HD, EINVAL, free_iob(), ICMP_ECHO_REQUEST, ICMP_ECHO_RESPONSE, iob_disown, iob_len(), NULL, strerror(), tcpip_chksum(), tcpip_tx(), and icmp_header::type.

                                                    {
        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;
}

---

Variable Documentation

struct tcpip_protocol icmp_protocol __tcpip_protocol [read]

Initial value:

 {
        .name = "ICMP",
        .rx = icmp_rx,
        .tcpip_proto = IP_ICMP,
}

ICMP TCP/IP protocol.

Definition at line 34 of file icmp.c.