#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);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,.minmtu=	0,.maxmtu=	64000,.maclen=	0,.bind=		netdevbind,.unbind=	netdevunbind,.bwrite=	netdevbwrite,.unbindonclose=	0,}; /* *  called to bind an IP ifc to a generic network device *  called with ifc qlock'd */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->mchan = mchan;	er->f = ifc->conv->p->f; 	ifc->arg = er; 	kproc("netdevread", netdevread, ifc);} /* *  called with ifc wlock'd */static voidnetdevunbind(Ipifc *ifc){	Netdevrock *er = ifc->arg; 	if(er->readp != nil)		postnote(er->readp, 1, "unbind", 0); 	/* wait for readers to die */	while(er->readp != nil)		tsleep(&up->sleep, return0, 0, 300); 	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*){	Netdevrock *er = ifc->arg; 	if(bp->next)		bp = concatblock(bp);	if(BLEN(bp) < ifc->minmtu)		bp = adjustblock(bp, ifc->minmtu); 	devtab[er->mchan->type]->bwrite(er->mchan, bp, 0);	ifc->out++;} /* *  process to read from the device */static voidnetdevread(void *a){	Ipifc *ifc;	Block *bp;	Netdevrock *er;	char *argv[1]; 	ifc = a;	er = ifc->arg;	er->readp = up;	/* hide identity under a rock for unbind */	if(waserror()){		er->readp = nil;		pexit("hangup", 1);	}	for(;;){		bp = devtab[er->mchan->type]->bread(er->mchan, ifc->maxmtu, 0);		if(bp == nil){			/*			 * get here if mchan is a pipe and other side hangs up			 * clean up this interface & get outZZZ is this a good idea?			 */			poperror();			er->readp = nil;			argv[0] = "unbind";			if(!waserror())				ifc->conv->p->ctl(ifc->conv, argv, 1);			pexit("hangup", 1);		}		if(!canrlock(ifc)){			freeb(bp);			continue;		}		if(waserror()){			runlock(ifc);			nexterror();		}		ifc->in++;		if(ifc->lifc == nil)			freeb(bp);		else			ipiput(er->f, ifc, bp);		runlock(ifc);		poperror();	}} voidnetdevmediumlink(void){	addipmedium(&netdevmedium);}