lwip/netif/loopif.c

   1 /*
   2  * Copyright (c) 2001-2004 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
  33 #include <time.h>
  34 #include "lwp_watchdog.h"
  35 #include "lwip/opt.h"
  36
  37 #if LWIP_HAVE_LOOPIF
  38
  39 #include "netif/loopif.h"
  40 #include "lwip/mem.h"
  41
  42 #if defined(LWIP_DEBUG) && defined(LWIP_TCPDUMP)
  43 #include "netif/tcpdump.h"
  44 #endif /* LWIP_DEBUG && LWIP_TCPDUMP */
  45
  46 #include "lwip/tcp.h"
  47 #include "lwip/ip.h"
  48
  49 #include "lwp_watchdog.h"
  50
  51 #define LOOP_TIMER_ID                   0x00070045
  52
  53 static u64 loopif_ticks;
  54 static wd_cntrl loopif_tmr_cntrl;
  55
  56 extern unsigned int timespec_to_interval(const struct timespec *);
  57
  58 static void
  59 loopif_input( void * arg )
  60 {
  61         struct netif *netif = (struct netif*)(((void**)arg)[0]);
  62         struct pbuf *r = (struct pbuf*)(((void**)arg)[1]);
  63
  64         mem_free(arg);
  65         netif->input(r,netif);
  66 }
  67
  68 static err_t
  69 loopif_output(struct netif *netif, struct pbuf *p,
  70        struct ip_addr *ipaddr)
  71 {
  72   struct pbuf *q, *r;
  73   char *ptr;
  74   void **arg;
  75
  76 #if defined(LWIP_DEBUG) && defined(LWIP_TCPDUMP)
  77   tcpdump(p);
  78 #endif /* LWIP_DEBUG && LWIP_TCPDUMP */
  79
  80   r = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);
  81   if (r != NULL) {
  82     ptr = r->payload;
  83
  84     for(q = p; q != NULL; q = q->next) {
  85       memcpy(ptr, q->payload, q->len);
  86       ptr += q->len;
  87     }
  88
  89     arg = mem_malloc( sizeof( void *[2]));
  90         if( NULL == arg ) {
  91                 return ERR_MEM;
  92         }
  93
  94         arg[0] = netif;
  95         arg[1] = r;
  96         /**
  97          * workaround (patch #1779) to try to prevent bug #2595:
  98          * When connecting to "localhost" with the loopif interface,
  99          * tcp_output doesn't get the opportunity to finnish sending the
 100          * segment before tcp_process gets it, resulting in tcp_process
 101          * referencing pcb->unacked-> which still is NULL.
 102          *
 103          * TODO: Is there still a race condition here? Leon
 104          */
 105         __lwp_wd_initialize(&loopif_tmr_cntrl,loopif_input,LOOP_TIMER_ID,arg);
 106         __lwp_wd_insert_ticks(&loopif_tmr_cntrl,loopif_ticks);
 107
 108     return ERR_OK;
 109   }
 110   return ERR_MEM;
 111 }
 112
 113 err_t
 114 loopif_init(struct netif *netif)
 115 {
 116   struct timespec tb;
 117
 118   netif->name[0] = 'l';
 119   netif->name[1] = 'o';
 120 #if 0 /** TODO: I think this should be enabled, or not? Leon */
 121   netif->input = loopif_input;
 122 #endif
 123   netif->output = loopif_output;
 124
 125  tb.tv_sec = 0;
 126  tb.tv_nsec = 10*TB_NSPERMS;
 127  loopif_ticks = __lwp_wd_calc_ticks(&tb);
 128
 129  return ERR_OK;
 130 }
 131
 132 #endif /* LWIP_HAVE_LOOPIF */
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