#include "u.h"#include "../port/lib.h"#include "mem.h"#include "dat.h"#include "fns.h"#include "../port/error.h" #include "ip.h" static void	netdevbind(Ipifc *ifc, int argc, char **argv);static void	netdevunbind(Ipifc *ifc);static void	netdevbwrite(Ipifc *ifc, Block *bp, int version, uchar *ip, Routehint*);static void	netdevread(void *a); typedef struct	Netdevrock Netdevrock;struct Netdevrock{	Fs	*f;		/* file system we belong to */	Proc	*readp;		/* reading process */	Chan	*mchan;		/* Data channel */}; Medium netdevmedium ={.name=		"netdev",.hsize=		0,.mintu=	0,.maxtu=	64000,.maclen=	0,.bind=		netdevbind,.unbind=	netdevunbind,.bwrite=	netdevbwrite,.unbindonclose=	0,}; /* *  called to bind an IP ifc to a generic network device */static voidnetdevbind(Ipifc *ifc, int argc, char **argv){	Chan *mchan;	Netdevrock *er; 	if(argc < 2)		error(Ebadarg); 	mchan = namec(argv[2], Aopen, ORDWR, 0); 	er = smalloc(sizeof(*er));	er->readp = (void*)-1;	er->mchan = mchan;	er->f = ifc->conv->p->f; 	ifc->arg = er; 	kproc("netdevread", netdevread, ifc);} static voidnetdevunbind(Ipifc *ifc){	Netdevrock *er = ifc->arg; 	while(waserror())		;	/* wait for reader to start */	while(er->readp == (void*)-1)		tsleep(&up->sleep, return0, 0, 300); 	if(er->readp != nil && er->readp != up)		postnote(er->readp, 1, "unbind", 0);	poperror(); 	while(waserror())		;	/* wait for reader to die */	while(er->readp != nil && er->readp != up)		tsleep(&up->sleep, return0, 0, 300);	poperror(); 	if(er->mchan != nil)		cclose(er->mchan); 	free(er);} /* *  called by ipoput with a single block to write */static voidnetdevbwrite(Ipifc *ifc, Block *bp, int, uchar*, Routehint*){	Netdevrock *er = ifc->arg;	devtab[er->mchan->type]->bwrite(er->mchan, bp, 0);} /* *  process to read from the device */static voidnetdevread(void *a){	Ipifc *ifc;	Block *bp;	Netdevrock *er; 	ifc = a;	er = ifc->arg;	er->readp = up;	/* hide identity under a rock for unbind */	if(!waserror())	for(;;){		bp = devtab[er->mchan->type]->bread(er->mchan, ifc->maxtu, 0);		if(bp == nil){			poperror();			break;		}		rlock(ifc);		if(waserror()){			runlock(ifc);			continue;		}		ipiput4(er->f, ifc, bp);		runlock(ifc);		poperror();	}	if(mediumunbindifc(ifc) != nil)		er->readp = nil;	/* someone else is doing the unbind */	pexit("hangup", 1);} voidnetdevmediumlink(void){	addipmedium(&netdevmedium);}