icmpv4.c

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/*
 * Copyright (C) 2013 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., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

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

/** @file
 *
 * ICMPv4 protocol
 *
 */

struct icmp_echo_protocol icmpv4_echo_protocol __icmp_echo_protocol;

/**
 * Process a received packet
 *
 * @v iobuf             I/O buffer
 * @v netdev            Network device
 * @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 icmpv4_rx ( struct io_buffer *iobuf,
                       struct net_device *netdev __unused,
                       struct sockaddr_tcpip *st_src,
                       struct sockaddr_tcpip *st_dest __unused,
                       uint16_t pshdr_csum __unused ) {
        struct icmp_header *icmp = iobuf->data;
        size_t len = iob_len ( iobuf );
        unsigned int csum;
        unsigned int type;
        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 discard;
        }

        /* 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 discard;
        }

        /* Handle ICMP packet */
        type = icmp->type;
        switch ( type ) {
        case ICMP_ECHO_REQUEST:
                return icmp_rx_echo_request ( iobuf, st_src,
                                              &icmpv4_echo_protocol );
        case ICMP_ECHO_REPLY:
                return icmp_rx_echo_reply ( iobuf, st_src );
        default:
                DBG ( "ICMP ignoring type %d\n", type );
                rc = 0;
                break;
        }

 discard:
        free_iob ( iobuf );
        return rc;
}

/** ICMPv4 TCP/IP protocol */
struct tcpip_protocol icmpv4_protocol __tcpip_protocol = {
        .name = "ICMPv4",
        .rx = icmpv4_rx,
        .tcpip_proto = IP_ICMP,
};

/** ICMPv4 echo protocol */
struct icmp_echo_protocol icmpv4_echo_protocol __icmp_echo_protocol = {
        .family = AF_INET,
        .request = ICMP_ECHO_REQUEST,
        .reply = ICMP_ECHO_REPLY,
        .tcpip_protocol = &icmpv4_protocol,
        .net_checksum = 0,
};