sys/src/9/ip/netdevmedium.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 static void     netdevbind(Ipifc *ifc, int argc, char **argv);
  11 static void     netdevunbind(Ipifc *ifc);
  12 static void     netdevbwrite(Ipifc *ifc, Block *bp, int version, uchar *ip);
  13 static void     netdevread(void *a);
  14
  15 typedef struct  Netdevrock Netdevrock;
  16 struct Netdevrock
  17 {
  18         Fs      *f;             /* file system we belong to */
  19         Proc    *readp;         /* reading process */
  20         Chan    *mchan;         /* Data channel */
  21 };
  22
  23 Medium netdevmedium =
  24 {
  25 .name=          "netdev",
  26 .hsize=         0,
  27 .mintu= 0,
  28 .maxtu= 64000,
  29 .maclen=        0,
  30 .bind=          netdevbind,
  31 .unbind=        netdevunbind,
  32 .bwrite=        netdevbwrite,
  33 .unbindonclose= 0,
  34 };
  35
  36 /*
  37  *  called to bind an IP ifc to a generic network device
  38  *  called with ifc qlock'd
  39  */
  40 static void
  41 netdevbind(Ipifc *ifc, int argc, char **argv)
  42 {
  43         Chan *mchan;
  44         Netdevrock *er;
  45
  46         if(argc < 2)
  47                 error(Ebadarg);
  48
  49         mchan = namec(argv[2], Aopen, ORDWR, 0);
  50
  51         er = smalloc(sizeof(*er));
  52         er->mchan = mchan;
  53         er->f = ifc->conv->p->f;
  54
  55         ifc->arg = er;
  56
  57         kproc("netdevread", netdevread, ifc);
  58 }
  59
  60 /*
  61  *  called with ifc wlock'd
  62  */
  63 static void
  64 netdevunbind(Ipifc *ifc)
  65 {
  66         Netdevrock *er = ifc->arg;
  67
  68         if(er->readp != nil)
  69                 postnote(er->readp, 1, "unbind", 0);
  70
  71         /* wait for readers to die */
  72         while(er->readp != nil)
  73                 tsleep(&up->sleep, return0, 0, 300);
  74
  75         if(er->mchan != nil)
  76                 cclose(er->mchan);
  77
  78         free(er);
  79 }
  80
  81 /*
  82  *  called by ipoput with a single block to write
  83  */
  84 static void
  85 netdevbwrite(Ipifc *ifc, Block *bp, int, uchar*)
  86 {
  87         Netdevrock *er = ifc->arg;
  88
  89         if(BLEN(bp) < ifc->mintu)
  90                 bp = adjustblock(bp, ifc->mintu);
  91
  92         devtab[er->mchan->type]->bwrite(er->mchan, bp, 0);
  93         ifc->out++;
  94 }
  95
  96 /*
  97  *  process to read from the device
  98  */
  99 static void
 100 netdevread(void *a)
 101 {
 102         Ipifc *ifc;
 103         Block *bp;
 104         Netdevrock *er;
 105         char *argv[1];
 106
 107         ifc = a;
 108         er = ifc->arg;
 109         er->readp = up; /* hide identity under a rock for unbind */
 110         if(waserror()){
 111                 er->readp = nil;
 112                 pexit("hangup", 1);
 113         }
 114         for(;;){
 115                 bp = devtab[er->mchan->type]->bread(er->mchan, ifc->maxtu, 0);
 116                 if(bp == nil){
 117                         /*
 118                          * get here if mchan is a pipe and other side hangs up
 119                          * clean up this interface & get out
 120 ZZZ is this a good idea?
 121                          */
 122                         poperror();
 123                         er->readp = nil;
 124                         argv[0] = "unbind";
 125                         if(!waserror())
 126                                 ifc->conv->p->ctl(ifc->conv, argv, 1);
 127                         pexit("hangup", 1);
 128                 }
 129                 if(!canrlock(ifc)){
 130                         freeb(bp);
 131                         continue;
 132                 }
 133                 if(waserror()){
 134                         runlock(ifc);
 135                         nexterror();
 136                 }
 137                 ifc->in++;
 138                 if(ifc->lifc == nil)
 139                         freeb(bp);
 140                 else
 141                         ipiput4(er->f, ifc, bp);
 142                 runlock(ifc);
 143                 poperror();
 144         }
 145 }
 146
 147 void
 148 netdevmediumlink(void)
 149 {
 150         addipmedium(&netdevmedium);
 151 }