icmpin.c

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/*
 * Copyright (C) 2001-2004 by egnite Software GmbH. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of
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 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY EGNITE SOFTWARE GMBH AND CONTRIBUTORS
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 * For additional information see http://www.ethernut.de/
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 * -
 * Portions Copyright (C) 2000 David J. Hudson <dave@humbug.demon.co.uk>
 *
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 * -
 * Portions Copyright (c) 1983, 1993 by
 *  The Regents of the University of California.  All rights reserved.
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 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
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 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
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 *    may be used to endorse or promote products derived from this software
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
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 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
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 */

/*
 * $Log$
 * Revision 1.9  2009/02/22 12:39:51  olereinhardt
 * Added ICMP destination unreachable support for UDP sockets and give a
 * more detailed errno to TCP sockets as well. ICMP support for UDP sockets
 * will just be enabled when defining NUT_UDP_ICMP_SUPPORT int the configurator
 *
 * Revision 1.8  2008/10/05 16:48:52  haraldkipp
 * Security fix. Check various lengths of incoming packets.
 *
 * Revision 1.7  2008/08/11 07:00:29  haraldkipp
 * BSD types replaced by stdint types (feature request #1282721).
 *
 * Revision 1.6  2008/05/24 22:23:55  olereinhardt
 * Fixed cvs log message
 *
 * Revision 1.5  2008/05/24 22:22:26  olereinhardt
 * Fixed size comparision in NutIcmpUnreach
 *
 * Revision 1.4  2004/03/18 10:28:36  haraldkipp
 * Comments updated
 *
 * Revision 1.3  2004/02/06 19:23:59  drsung
 * Bugfix. After last changes, ping didn't work any more. Thanks to Pavel Celeda, who discovered this bug.
 *
 * Revision 1.2  2004/02/02 18:59:25  drsung
 * Some more ICMP support added.
 *
 * Revision 1.1.1.1  2003/05/09 14:41:28  haraldkipp
 * Initial using 3.2.1
 *
 * Revision 1.11  2003/02/04 18:14:57  harald
 * Version 3 released
 *
 * Revision 1.10  2002/06/26 17:29:35  harald
 * First pre-release with 2.4 stack
 *
 */

#include <netinet/ip_icmp.h>
#include <netinet/ipcsum.h>
#include <netinet/icmp.h>
#include <sys/socket.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netinet/in.h>
#include <errno.h>


static CONST int icmp_code2errno[16] = 
{
    ENETUNREACH,
    EHOSTUNREACH,
    ENOPROTOOPT,
    ECONNREFUSED,       
    EMSGSIZE,
    EOPNOTSUPP,
    ENETUNREACH,
    EHOSTDOWN,
    ENETUNREACH,
    ENETUNREACH,
    EHOSTUNREACH,
    ENETUNREACH,
    EHOSTUNREACH,
    EHOSTUNREACH,
    EHOSTUNREACH,
    EHOSTUNREACH,
};

/*
 * Send out ICMP echo response.
 */
static int NutIcmpReflect(NUTDEVICE * dev, uint8_t type, NETBUF * nb)
{
    IPHDR *ip;
    uint32_t dest;
    IFNET *nif;

    ip = nb->nb_nw.vp;
    dest = ip->ip_src;
    nif = dev->dev_icb;
    ip->ip_src = nif->if_local_ip;
    ip->ip_ttl = MAXTTL;

    return NutIcmpOutput(type, dest, nb);
}

/*
 * Process incoming ICMP messages for destination unreachable.
 */
static int NutIcmpUnreach(NETBUF * nb, int icmp_code)
{
    IPHDR *ih;

    if (nb->nb_ap.sz < sizeof(IPHDR) + 8)
        return -1;

    ih = nb->nb_ap.vp;
    
    switch (ih->ip_p) {
        case IPPROTO_TCP: 
        {
            TCPHDR *th;
            TCPSOCKET *sock_tcp;

            th = (TCPHDR *) ((char *) ih) + sizeof(IPHDR);
            sock_tcp = NutTcpFindSocket(th->th_dport, th->th_sport, ih->ip_src);
            if (sock_tcp == 0)
                return -1;

            if (sock_tcp->so_state != TCPS_SYN_SENT && sock_tcp->so_state != TCPS_ESTABLISHED)
                return -1;

            NutTcpAbortSocket(sock_tcp, icmp_code2errno[icmp_code]);
        }
        break;

#ifdef NUT_UDP_ICMP_SUPPORT               
        case IPPROTO_UDP: 
        {
            UDPHDR *uh;
            UDPSOCKET *sock_udp;

            uh = (UDPHDR *) (((char *) ih) + sizeof(IPHDR));
            sock_udp = NutUdpFindSocket(uh->uh_dport);

            if (sock_udp == NULL)
                return -1;
            
            if (NutUdpSetSocketError(sock_udp, ih->ip_dst, uh->uh_dport, icmp_code2errno[icmp_code]))
                return -1;
        }    
        break;
#endif            
            
        default:
            return -1;
    }


    return 0;
}

void NutIcmpInput(NUTDEVICE * dev, NETBUF * nb)
{
    ICMPHDR *icp = (ICMPHDR *) nb->nb_tp.vp;

    /* Silently discard packets, which are too small. */
    if (icp == NULL || nb->nb_tp.sz < sizeof(ICMPHDR)) {
        NutNetBufFree(nb);
        return;
    }

    nb->nb_ap.sz = nb->nb_tp.sz - sizeof(ICMPHDR);
    if (nb->nb_ap.sz) {
        nb->nb_ap.vp = icp + 1;
        nb->nb_tp.sz = sizeof(ICMPHDR);
    }

    switch (icp->icmp_type) {
    case ICMP_ECHO:
        if (NutIcmpReflect(dev, ICMP_ECHOREPLY, nb)) {
            break;
        }
    case ICMP_UNREACH:
        NutIcmpUnreach(nb, icp->icmp_code);
    default:
        NutNetBufFree(nb);
    }
}