modules/network/SMSTCPIP/loopif.c

   1 /*
   2  * Copyright (c) 2001-2003 Swedish Institute of Computer Science.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without modification,
   6  * are permitted provided that the following conditions are met:
   7  *
   8  * 1. Redistributions of source code must retain the above copyright notice,
   9  *    this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright notice,
  11  *    this list of conditions and the following disclaimer in the documentation
  12  *    and/or other materials provided with the distribution.
  13  * 3. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  19  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  21  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  22  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  23  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  24  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  25  * OF SUCH DAMAGE.
  26  *
  27  * This file is part of the lwIP TCP/IP stack.
  28  *
  29  * Author: Adam Dunkels <adam@sics.se>
  30  *
  31  */
  32 #include "lwip/opt.h"
  33
  34 #if LWIP_HAVE_LOOPIF
  35
  36 #include "netif/loopif.h"
  37 #include "lwip/mem.h"
  38
  39 #if defined(LWIP_DEBUG) && defined(LWIP_TCPDUMP)
  40 #include "netif/tcpdump.h"
  41 #endif /* LWIP_DEBUG && LWIP_TCPDUMP */
  42
  43 #include "lwip/tcp.h"
  44 #include "lwip/ip.h"
  45
  46 #include "sysclib.h"
  47
  48 static void
  49 loopif_input( void * arg )
  50 {
  51         struct netif *netif = (struct netif *)( ((void **)arg)[ 0 ] );
  52         struct pbuf *r = (struct pbuf *)( ((void **)arg)[ 1 ] );
  53
  54         mem_free( arg );
  55         netif -> input( r, netif );
  56 }
  57
  58 static err_t
  59 loopif_output(struct netif *netif, struct pbuf *p,
  60        struct ip_addr *ipaddr)
  61 {
  62   struct pbuf *q, *r;
  63   char *ptr;
  64   void **arg;
  65
  66 #if defined(LWIP_DEBUG) && defined(LWIP_TCPDUMP)
  67   tcpdump(p);
  68 #endif /* LWIP_DEBUG && LWIP_TCPDUMP */
  69
  70   r = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);
  71   if (r != NULL) {
  72     ptr = r->payload;
  73
  74     for(q = p; q != NULL; q = q->next) {
  75       mips_memcpy(ptr, q->payload, q->len);
  76       ptr += q->len;
  77     }
  78
  79     arg = mem_malloc( sizeof( void *[2]));
  80         if( NULL == arg ) {
  81                 return ERR_MEM;
  82         }
  83
  84         arg[0] = netif;
  85         arg[1] = r;
  86         /**
  87          * workaround (patch #1779) to try to prevent bug #2595:
  88          * When connecting to "localhost" with the loopif interface,
  89          * tcp_output doesn't get the opportunity to finnish sending the
  90          * segment before tcp_process gets it, resulting in tcp_process
  91          * referencing pcb->unacked-> which still is NULL.
  92          *
  93          * TODO: Is there still a race condition here? Leon
  94          */
  95         sys_timeout( 1, loopif_input, arg );
  96
  97     return ERR_OK;
  98   }
  99   return ERR_MEM;
 100 }
 101
 102 err_t
 103 loopif_init(struct netif *netif)
 104 {
 105   netif->name[0] = 'l';
 106   netif->name[1] = 'o';
 107 #if 0 /** TODO: I think this should be enabled, or not? Leon */
 108   netif->input = loopif_input;
 109 #endif
 110   netif->output = loopif_output;
 111   return ERR_OK;
 112 }
 113
 114 #endif /* LWIP_HAVE_LOOPIF */
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