ethdemux.c

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00001 /*
00002  * Copyright (C) 2008 by egnite GmbH.
00003  * Copyright (c) 1982, 1989, 1993 by The Regents of the University of California.
00004  *
00005  * All rights reserved.
00006  *
00007  * Redistribution and use in source and binary forms, with or without
00008  * modification, are permitted provided that the following conditions
00009  * are met:
00010  *
00011  * 1. Redistributions of source code must retain the above copyright
00012  *    notice, this list of conditions and the following disclaimer.
00013  * 2. Redistributions in binary form must reproduce the above copyright
00014  *    notice, this list of conditions and the following disclaimer in the
00015  *    documentation and/or other materials provided with the distribution.
00016  * 3. Neither the name of the copyright holders nor the names of
00017  *    contributors may be used to endorse or promote products derived
00018  *    from this software without specific prior written permission.
00019  *
00020  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00021  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00022  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
00023  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
00024  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
00025  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
00026  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
00027  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
00028  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
00029  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
00030  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00031  * SUCH DAMAGE.
00032  *
00033  * For additional information see http://www.ethernut.de/
00034  */
00035 
00048 #include <sys/types.h>
00049 #include <sys/heap.h>
00050 #include <netinet/if_ether.h>
00051 #include <net/ether.h>
00052 
00057 
00061 typedef struct _ETH_PROTOCOLS ETH_PROTOCOLS;
00062 
00063 struct _ETH_PROTOCOLS {
00064     ETH_PROTOCOLS *ethp_next;
00065     uint16_t ethp_type;
00066     uint16_t ethp_mask;
00067     int (*ethp_input)(NUTDEVICE *, NETBUF *);
00068 };
00069 
00070 static ETH_PROTOCOLS *eth_prot;
00071 
00082 static int NutEtherDemux(NUTDEVICE * dev, NETBUF * nb)
00083 {
00084     ETH_PROTOCOLS *ep;
00085     uint16_t type = ntohs(((ETHERHDR *)nb->nb_dl.vp)->ether_type);
00086 
00087     for (ep = eth_prot; ep; ep = ep->ethp_next) {
00088         if ((type & ep->ethp_mask) == ep->ethp_type) {
00089             if (ep->ethp_input && (*ep->ethp_input) (dev, nb) == 0) {
00090                 return 0;
00091             }
00092         }
00093     }
00094     return -1;
00095 }
00096 
00122 int NutRegisterEthHandler(uint16_t type, uint16_t mask, int (*hdlr)(NUTDEVICE *, NETBUF *))
00123 {
00124     ETH_PROTOCOLS *ep;
00125 
00126     /* Check existing registrations. */
00127     for (ep = eth_prot; ep; ep = ep->ethp_next) {
00128         if (ep->ethp_type == type && ep->ethp_mask == mask) {
00129             /* Found one. */
00130             break;
00131         }
00132     }
00133 
00134     if (ep == NULL) {
00135         /* No existing entry. Allocate a new one. */
00136         ep = NutHeapAllocClear(sizeof(ETH_PROTOCOLS));
00137         if (ep == NULL) {
00138             return -1;
00139         }
00140         /* Set type and mask of our new entry. */
00141         ep->ethp_type = type;
00142         ep->ethp_mask = mask;
00143         if (eth_prot == NULL) {
00144             /* This is the first registration. Set the list root ... */
00145             eth_prot = ep;
00146             /* ... and enable our demultiplexer. */
00147             ether_demux = NutEtherDemux;
00148         } else {
00149             /* Not the first registration. Insert new handler at the top. */
00150             ep->ethp_next = eth_prot;
00151             eth_prot = ep;
00152         }
00153     }
00154     /* Finally set the handler function pointer of the new or existing 
00155     ** entry. */
00156     ep->ethp_input = hdlr;
00157 
00158     return 0;
00159 }
00160 

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