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Annotation of embedaddon/dhcp/common/ethernet.c, revision 1.1

1.1     ! misho       1: /* ethernet.c
        !             2: 
        !             3:    Packet assembly code, originally contributed by Archie Cobbs. */
        !             4: 
        !             5: /*
        !             6:  * Copyright (c) 2004,2007,2009 by Internet Systems Consortium, Inc. ("ISC")
        !             7:  * Copyright (c) 1996-2003 by Internet Software Consortium
        !             8:  *
        !             9:  * Permission to use, copy, modify, and distribute this software for any
        !            10:  * purpose with or without fee is hereby granted, provided that the above
        !            11:  * copyright notice and this permission notice appear in all copies.
        !            12:  *
        !            13:  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
        !            14:  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
        !            15:  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
        !            16:  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
        !            17:  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
        !            18:  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
        !            19:  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
        !            20:  *
        !            21:  *   Internet Systems Consortium, Inc.
        !            22:  *   950 Charter Street
        !            23:  *   Redwood City, CA 94063
        !            24:  *   <info@isc.org>
        !            25:  *   https://www.isc.org/
        !            26:  *
        !            27:  * This software has been written for Internet Systems Consortium
        !            28:  * by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc.
        !            29:  * To learn more about Internet Systems Consortium, see
        !            30:  * ``https://www.isc.org/''.  To learn more about Vixie Enterprises,
        !            31:  * see ``http://www.vix.com''.   To learn more about Nominum, Inc., see
        !            32:  * ``http://www.nominum.com''.
        !            33:  */
        !            34: 
        !            35: #include "dhcpd.h"
        !            36: 
        !            37: #if defined (PACKET_ASSEMBLY) || defined (PACKET_DECODING)
        !            38: #include "includes/netinet/if_ether.h"
        !            39: #endif /* PACKET_ASSEMBLY || PACKET_DECODING */
        !            40: 
        !            41: #if defined (PACKET_ASSEMBLY)
        !            42: /* Assemble an hardware header... */
        !            43: 
        !            44: void assemble_ethernet_header (interface, buf, bufix, to)
        !            45:        struct interface_info *interface;
        !            46:        unsigned char *buf;
        !            47:        unsigned *bufix;
        !            48:        struct hardware *to;
        !            49: {
        !            50:        struct isc_ether_header eh;
        !            51: 
        !            52:        if (to && to -> hlen == 7) /* XXX */
        !            53:                memcpy (eh.ether_dhost, &to -> hbuf [1],
        !            54:                        sizeof eh.ether_dhost);
        !            55:        else
        !            56:                memset (eh.ether_dhost, 0xff, sizeof (eh.ether_dhost));
        !            57:        if (interface -> hw_address.hlen - 1 == sizeof (eh.ether_shost))
        !            58:                memcpy (eh.ether_shost, &interface -> hw_address.hbuf [1],
        !            59:                        sizeof (eh.ether_shost));
        !            60:        else
        !            61:                memset (eh.ether_shost, 0x00, sizeof (eh.ether_shost));
        !            62: 
        !            63:        eh.ether_type = htons (ETHERTYPE_IP);
        !            64: 
        !            65:        memcpy (&buf [*bufix], &eh, ETHER_HEADER_SIZE);
        !            66:        *bufix += ETHER_HEADER_SIZE;
        !            67: }
        !            68: #endif /* PACKET_ASSEMBLY */
        !            69: 
        !            70: #ifdef PACKET_DECODING
        !            71: /* Decode a hardware header... */
        !            72: 
        !            73: ssize_t decode_ethernet_header (interface, buf, bufix, from)
        !            74:      struct interface_info *interface;
        !            75:      unsigned char *buf;
        !            76:      unsigned bufix;
        !            77:      struct hardware *from;
        !            78: {
        !            79:   struct isc_ether_header eh;
        !            80: 
        !            81:   memcpy (&eh, buf + bufix, ETHER_HEADER_SIZE);
        !            82: 
        !            83: #ifdef USERLAND_FILTER
        !            84:   if (ntohs (eh.ether_type) != ETHERTYPE_IP)
        !            85:          return -1;
        !            86: #endif
        !            87:   memcpy (&from -> hbuf [1], eh.ether_shost, sizeof (eh.ether_shost));
        !            88:   from -> hbuf [0] = ARPHRD_ETHER;
        !            89:   from -> hlen = (sizeof eh.ether_shost) + 1;
        !            90: 
        !            91:   return ETHER_HEADER_SIZE;
        !            92: }
        !            93: #endif /* PACKET_DECODING */