sys/src/9/ip/loopbackmedium.c

   1 #include "u.h"
   2 #include "../port/lib.h"
   3 #include "mem.h"
   4 #include "dat.h"
   5 #include "fns.h"
   6 #include "../port/error.h"
   7
   8 #include "ip.h"
   9
  10 enum
  11 {
  12         Maxtu=  16*1024,
  13 };
  14
  15 typedef struct LB LB;
  16 struct LB
  17 {
  18         Proc    *readp;
  19         Queue   *q;
  20         Fs      *f;
  21 };
  22
  23 static void loopbackread(void *a);
  24
  25 static void
  26 loopbackbind(Ipifc *ifc, int, char**)
  27 {
  28         LB *lb;
  29
  30         lb = smalloc(sizeof(*lb));
  31         lb->f = ifc->conv->p->f;
  32         lb->q = qopen(1024*1024, Qmsg, nil, nil);
  33         ifc->arg = lb;
  34
  35         kproc("loopbackread", loopbackread, ifc);
  36
  37 }
  38
  39 static void
  40 loopbackunbind(Ipifc *ifc)
  41 {
  42         LB *lb = ifc->arg;
  43
  44         if(lb->readp)
  45                 postnote(lb->readp, 1, "unbind", 0);
  46
  47         /* wait for reader to die */
  48         while(lb->readp != 0)
  49                 tsleep(&up->sleep, return0, 0, 300);
  50
  51         /* clean up */
  52         qfree(lb->q);
  53         free(lb);
  54 }
  55
  56 static void
  57 loopbackbwrite(Ipifc *ifc, Block *bp, int, uchar*)
  58 {
  59         LB *lb;
  60
  61         lb = ifc->arg;
  62         if(qpass(lb->q, bp) < 0)
  63                 ifc->outerr++;
  64         ifc->out++;
  65 }
  66
  67 static void
  68 loopbackread(void *a)
  69 {
  70         Ipifc *ifc;
  71         Block *bp;
  72         LB *lb;
  73
  74         ifc = a;
  75         lb = ifc->arg;
  76         lb->readp = up; /* hide identity under a rock for unbind */
  77         if(waserror()){
  78                 lb->readp = nil;
  79                 pexit("hangup", 1);
  80         }
  81         for(;;){
  82                 bp = qbread(lb->q, Maxtu);
  83                 if(bp == nil)
  84                         continue;
  85                 if(!canrlock(ifc)){
  86                         freeb(bp);
  87                         continue;
  88                 }
  89                 if(waserror()){
  90                         runlock(ifc);
  91                         nexterror();
  92                 }
  93                 ifc->in++;
  94                 if(ifc->lifc == nil)
  95                         freeb(bp);
  96                 else
  97                         ipiput4(lb->f, ifc, bp);
  98                 runlock(ifc);
  99                 poperror();
 100         }
 101 }
 102
 103 Medium loopbackmedium =
 104 {
 105 .hsize=         0,
 106 .mintu=         0,
 107 .maxtu=         Maxtu,
 108 .maclen=        0,
 109 .name=          "loopback",
 110 .bind=          loopbackbind,
 111 .unbind=        loopbackunbind,
 112 .bwrite=        loopbackbwrite,
 113 };
 114
 115 void
 116 loopbackmediumlink(void)
 117 {
 118         addipmedium(&loopbackmedium);
 119 }