#include "u.h"#include "../port/lib.h"#include "mem.h"#include "dat.h"#include "fns.h"#include "../port/error.h" #include "ip.h" enum {	X		= 0,			/* dimension */	Y		= 1,	Z		= 2,	N		= 3, 	Chunk		= 32,			/* granularity of FIFO */	Pchunk		= 8,			/* Chunks in a packet */}; typedef struct Th Th;struct Th {	u8int	_0_[1];				/* Tpkt: 8 bytes */	u8int	hint;					/* ignored by IP for now */	u8int	_1_[1];	u8int	dst[N];				/* Destination Coordinates */	u8int	_6_[2];	u8int	_8_[8];				/* Tpkt: padding */ 	u8int	_16_[16];			/* Ipv4 header: 20 bytes */	u8int	ipv4dst[4];}; typedef struct Rock Rock;struct Rock {	Fs*	fs;				/* file system we belong to */	Proc*	read4p;				/* v4 read process */	Chan*	mchan4;				/* v4 data channel */ 	u8int	size[N];}; /* * Called by ipoput with a single block to write. */static voidtorusbwrite(Ipifc* ifc, Block* b, int, uchar*){	Th *th;	Rock *r;	int i, n; 	r = ifc->arg; 	b = padblock(b, ifc->medium->hsize);	if(b->next)		b = concatblock(b);	n = ROUNDUP(BLEN(b), Chunk);	if(BLEN(b) < n)		b = adjustblock(b, n); 	/*	 * The naïve mapping of IP address to torus address is	 * to assign a Class A network to the torus and set the	 * 3 octets of the host number to x.y.z, with z being	 * the least significant. However, there will be a root	 * compute node with an all zero torus address and that	 * is reserved for use as a network number. Therefore	 * the mapping is modified by adding 1 to the torus z	 * coordinate to create the least significant octet of	 * the IP address.	 * Silently toss packets with a host address out of range.	 * The torus will generate an unrecoverable error if it	 * sees an address outwith its dimensions.	 * Should there be a some ICMP notification thingy here	 * (address unreachable)?	 */	th = (Th*)b->rp;	th->hint = 0;	th->dst[X] = th->ipv4dst[1];	th->dst[Y] = th->ipv4dst[2];	th->dst[Z] = th->ipv4dst[3]-1;	if(th->dst[Z] >= 254){				/* IP was 255 or 0 */		freeb(b);		return;	}	for(i = 0; i < N; i++){		if(th->dst[i] >= r->size[i]){			freeb(b);			return;		}	} 	r->mchan4->dev->bwrite(r->mchan4, b, 0);	ifc->out++;} /* * Process to read from the device. */static voidtorusread4(void* a){	Rock *r;	Block *b;	Ipifc *ifc; 	ifc = a;	r = ifc->arg;	r->read4p = up;	if(waserror()){		r->read4p = nil;		pexit("hangup", 1);	}	for(;;){		b = r->mchan4->dev->bread(r->mchan4, ifc->maxtu, 0);		if(!canrlock(ifc)){			freeb(b);			continue;		}		if(waserror()){			runlock(ifc);			nexterror();		}		ifc->in++;		b->rp += ifc->medium->hsize;		if(ifc->lifc == nil)			freeb(b);		else			ipiput4(r->fs, ifc, b);		runlock(ifc);		poperror();	}} /* * Called with ifc wlock'd. */static voidtorusunbind(Ipifc* ifc){	Rock *r; 	r = ifc->arg;	if(r->read4p != nil)		postnote(r->read4p, 1, "unbind", NUser); 	/* wait for readers to die */	while(r->read4p != nil)		tsleep(&up->sleep, return0, 0, 300); 	if(r->mchan4 != nil)		cclose(r->mchan4); 	free(r);} static inttorusparse(u8int d[3], char* item, char* buf){	int n;	char *p; 	if((p = strstr(buf, item)) == nil || (p != buf && *(p-1) != '\n'))		return -1;	n = strlen(item);	if(strlen(p) < n+sizeof(": x 0 y 0 z 0"))		return -1;	p += n+sizeof(": x ")-1;	if(strncmp(p-4, ": x ", 4) != 0)		return -1;	if((n = strtol(p, &p, 0)) > 255 || *p != ' ' || *(p+1) != 'y')		return -1;	d[0] = n;	if((n = strtol(p+2, &p, 0)) > 255 || *p != ' ' || *(p+1) != 'z')		return -1;	d[1] = n;	if((n = strtol(p+2, &p, 0)) > 255 || (*p != '\n' && *p != '\0'))		return -1;	d[2] = n; 	return 0;} /* * Called to bind an Ipifc to a torus device. * Ifc is qlock'd. */static voidtorusbind(Ipifc* ifc, int argc, char* argv[]){	int n;	Rock *r;	Chan *mchan4, *schan;	char *buf, stats[Maxpath]; 	if(argc < 2)		error(Ebadarg); 	mchan4 = nil;	buf = nil;	if(waserror()){		if(mchan4 != nil)			cclose(mchan4);		if(buf != nil)			free(buf);		nexterror();	} 	mchan4 = namec(argv[2], Aopen, ORDWR, 0); 	/*	 * Get the dimensions of the torus/mesh from the device	 * 'stats' file so attempts to send outside can be detected	 * in torusbwrite.	 */	snprint(stats, sizeof(stats), "%sstatus", argv[2]);	buf = smalloc(2*READSTR);	schan = namec(stats, Aopen, OREAD, 0);	if(waserror()){		cclose(schan);		nexterror();	}	n = schan->dev->read(schan, buf, 511, 0);	cclose(schan);	poperror();	buf[n] = 0; 	r = smalloc(sizeof(*r));	if(torusparse(r->size, "size", buf) < 0){		free(buf);		error(Eio);	} 	r->mchan4 = mchan4;	r->fs = ifc->conv->p->f;	ifc->arg = r;	ifc->mbps = 1001; 	free(buf);	poperror(); 	kproc("torusread4", torusread4, ifc);} static Medium torusmedium = {	.name		= "torus",	.hsize		= 16,	.mintu		= Chunk,	.maxtu		= Chunk*Pchunk,	.maclen		= N,	.bind		= torusbind,	.unbind		= torusunbind,	.bwrite		= torusbwrite,}; voidtorusmediumlink(void){	addipmedium(&torusmedium);}