#include	"u.h"#include	"../port/lib.h"#include	"mem.h"#include	"dat.h"#include	"fns.h"#include	"../port/error.h" #include	"ip.h"#include	"ipv6.h" enum{	IP4HDR		= 20,		/* sizeof(Ip4hdr) */	IP6HDR		= 40,		/* sizeof(Ip6hdr) */	IP_HLEN4	= 0x05,		/* Header length in words */	IP_DF		= 0x4000,	/* Don't fragment */	IP_MF		= 0x2000,	/* More fragments */	IP6FHDR		= 8, 		/* sizeof(Fraghdr6) */	IP_MAX		= (32*1024),	/* Maximum Internet packet size */}; #define IPV6CLASS(hdr) ((hdr->vcf[0]&0x0F)<<2 | (hdr->vcf[1]&0xF0)>>2)#define BLKIPVER(xp)	(((Ip6hdr*)((xp)->rp))->vcf[0]&0xF0)/* * This sleazy macro is stolen shamelessly from ip.c, see comment there. */#define BKFG(xp)	((Ipfrag*)((xp)->base)) typedef struct	IP	IP;typedef struct	Fragment4	Fragment4;typedef struct	Fragment6	Fragment6;typedef struct	Ipfrag	Ipfrag; Block*		ip6reassemble(IP*, int, Block*, Ip6hdr*);void		ipfragfree6(IP*, Fragment6*);Fragment6*	ipfragallo6(IP*);static Block*		procxtns(IP *ip, Block *bp, int doreasm);int		unfraglen(Block *bp, uchar *nexthdr, int setfh);Block*		procopts(Block *bp); /* MIB II counters */enum{	Forwarding,	DefaultTTL,	InReceives,	InHdrErrors,	InAddrErrors,	ForwDatagrams,	InUnknownProtos,	InDiscards,	InDelivers,	OutRequests,	OutDiscards,	OutNoRoutes,	ReasmTimeout,	ReasmReqds,	ReasmOKs,	ReasmFails,	FragOKs,	FragFails,	FragCreates, 	Nstats,}; static char *statnames[] ={[Forwarding]	"Forwarding",[DefaultTTL]	"DefaultTTL",[InReceives]	"InReceives",[InHdrErrors]	"InHdrErrors",[InAddrErrors]	"InAddrErrors",[ForwDatagrams]	"ForwDatagrams",[InUnknownProtos]	"InUnknownProtos",[InDiscards]	"InDiscards",[InDelivers]	"InDelivers",[OutRequests]	"OutRequests",[OutDiscards]	"OutDiscards",[OutNoRoutes]	"OutNoRoutes",[ReasmTimeout]	"ReasmTimeout",[ReasmReqds]	"ReasmReqds",[ReasmOKs]	"ReasmOKs",[ReasmFails]	"ReasmFails",[FragOKs]	"FragOKs",[FragFails]	"FragFails",[FragCreates]	"FragCreates",}; struct Fragment4{	Block*	blist;	Fragment4*	next;	ulong 	src;	ulong 	dst;	ushort	id;	ulong 	age;}; struct Fragment6{	Block*	blist;	Fragment6*	next;	uchar 	src[IPaddrlen];	uchar 	dst[IPaddrlen];	uint	id;	ulong 	age;}; struct Ipfrag{	ushort	foff;	ushort	flen;}; /* an instance of IP */struct IP{	ulong		stats[Nstats]; 	QLock		fraglock4;	Fragment4*	flisthead4;	Fragment4*	fragfree4;	Ref		id4; 	QLock		fraglock6;	Fragment6*	flisthead6;	Fragment6*	fragfree6;	Ref		id6; 	int		iprouting;	/* true if we route like a gateway */}; intipoput6(Fs *f, Block *bp, int gating, int ttl, int tos, Conv *c){	int tentative;	Ipifc *ifc;	uchar *gate, nexthdr;	Ip6hdr *eh;	int medialen, len, chunk, uflen, flen, seglen, lid, offset, fragoff, morefrags, blklen;	Route *r, *sr;	Fraghdr6 fraghdr;	Block *xp, *nb;	IP *ip;	int rv = 0; 	ip = f->ip; 	/* Fill out the ip header */	eh = (Ip6hdr*)(bp->rp); 	ip->stats[OutRequests]++; 	/* Number of uchars in data and ip header to write */	len = blocklen(bp);		tentative = iptentative(f, eh->src);	if(tentative){		netlog(f, Logip, "reject tx of packet with tentative src address\n");		goto free;	} 	if(gating){		chunk = nhgets(eh->ploadlen);		if(chunk > len){			ip->stats[OutDiscards]++;			netlog(f, Logip, "short gated packet\n");			goto free;		}		if(chunk + IPV6HDR_LEN < len)			len = chunk + IPV6HDR_LEN;	} 	if(len >= IP_MAX){//		print("len > IP_MAX, free\n");		ip->stats[OutDiscards]++;		netlog(f, Logip, "exceeded ip max size %I\n", eh->dst);		goto free;	} 	r = v6lookup(f, eh->dst, c);	if(r == nil){//		print("no route for %I, src %I free\n", eh->dst, eh->src);		ip->stats[OutNoRoutes]++;		netlog(f, Logip, "no interface %I\n", eh->dst);		rv = -1;		goto free;	} 	ifc = r->ifc;	if(r->type & (Rifc|Runi))		gate = eh->dst;	else	if(r->type & (Rbcast|Rmulti)) {		gate = eh->dst;		sr = v6lookup(f, eh->src, nil);		if(sr != nil && (sr->type & Runi))			ifc = sr->ifc;	}	else		gate = r->v6.gate; 	if(!gating)		eh->vcf[0] = IP_VER6;	eh->ttl = ttl;	if(!gating) {		eh->vcf[0] |= (tos >> 4);		eh->vcf[1] = (tos << 4);	} 	if(!canrlock(ifc)) {		goto free;	} 	if(waserror()){		runlock(ifc);		nexterror();	} 	if(ifc->m == nil) {		goto raise;	} 	/* If we dont need to fragment just send it */	medialen = ifc->maxtu - ifc->m->hsize;	if(len <= medialen) {		hnputs(eh->ploadlen, len-IPV6HDR_LEN);		ifc->m->bwrite(ifc, bp, V6, gate);		runlock(ifc);		poperror();		return 0;	} 	if(gating) 	if(ifc->reassemble <= 0) { 		/* v6 intermediate nodes are not supposed to fragment pkts;		   we fragment if ifc->reassemble is turned on; an exception		   needed for nat.		 */ 		ip->stats[OutDiscards]++;		icmppkttoobig6(f, ifc, bp);		netlog(f, Logip, "%I: gated pkts not fragmented\n", eh->dst);		goto raise;	}			/* start v6 fragmentation */	uflen = unfraglen(bp, &nexthdr, 1);	if(uflen > medialen) {		ip->stats[FragFails]++;		ip->stats[OutDiscards]++;		netlog(f, Logip, "%I: unfragmentable part too big\n", eh->dst);		goto raise;	} 	flen = len - uflen;	seglen = (medialen - (uflen + IP6FHDR)) & ~7;	if(seglen < 8) {		ip->stats[FragFails]++;		ip->stats[OutDiscards]++;		netlog(f, Logip, "%I: seglen < 8\n", eh->dst);		goto raise;	} 	lid = incref(&ip->id6);	fraghdr.nexthdr = nexthdr;	fraghdr.res = 0;	hnputl(fraghdr.id, lid); 	xp = bp;	offset = uflen;	while (xp != nil && offset && offset >= BLEN(xp)) {		offset -= BLEN(xp);		xp = xp->next;	}	xp->rp += offset; 	fragoff = 0; 	morefrags = 1; 	for(; fragoff < flen; fragoff += seglen) {		nb = allocb(uflen + IP6FHDR + seglen); 		if(fragoff + seglen >= flen) {			seglen = flen - fragoff;			morefrags = 0;		} 		hnputs(eh->ploadlen, seglen+IP6FHDR);		memmove(nb->wp, eh, uflen);		nb->wp += uflen; 		hnputs(fraghdr.offsetRM, fragoff); // last 3 bits must be 0		fraghdr.offsetRM[1] |= morefrags;		memmove(nb->wp, &fraghdr, IP6FHDR);		nb->wp += IP6FHDR; 		/* Copy data */		chunk = seglen;		while (chunk) {			if(!xp) {				ip->stats[OutDiscards]++;				ip->stats[FragFails]++;				freeblist(nb);				netlog(f, Logip, "!xp: chunk in v6%d\n", chunk);				goto raise;			}			blklen = chunk;			if(BLEN(xp) < chunk)				blklen = BLEN(xp);			memmove(nb->wp, xp->rp, blklen); 			nb->wp += blklen;			xp->rp += blklen;			chunk -= blklen;			if(xp->rp == xp->wp)				xp = xp->next; 		} 		ifc->m->bwrite(ifc, nb, V6, gate);		ip->stats[FragCreates]++;	}	ip->stats[FragOKs]++; raise:	runlock(ifc);	poperror();free:	freeblist(bp);		return rv;} voidipiput6(Fs *f, Ipifc *ifc, Block *bp){	int hl;	int hop, tos;	uchar proto;	Ip6hdr *h;	Proto *p;	int notforme;	int tentative;	uchar v6dst[IPaddrlen];	IP *ip;	Route *r, *sr; 	ip = f->ip;	ip->stats[InReceives]++; 	/*	 *  Ensure we have all the header info in the first	 *  block.  Make life easier for other protocols by	 *  collecting up to the first 64 bytes in the first block.	 */	if(BLEN(bp) < 64) {		hl = blocklen(bp);		if(hl < IP6HDR)			hl = IP6HDR;		if(hl > 64)			hl = 64;		bp = pullupblock(bp, hl);		if(bp == nil)			return;	} 	h = (Ip6hdr *)(bp->rp); 	memmove(&v6dst[0], &(h->dst)[0], IPaddrlen);	notforme = ipforme(f, v6dst) == 0;	tentative = iptentative(f, v6dst);  	if(tentative && (h->proto != ICMPv6)) {		print("tentative addr, drop\n");		freeblist(bp);		return;	} 	/* Check header version */	if(BLKIPVER(bp) != IP_VER6) {		ip->stats[InHdrErrors]++;		netlog(f, Logip, "ip: bad version %ux\n", (h->vcf[0]&0xF0)>>2);		freeblist(bp);		return;	} 	/* route */	if(notforme) {		if(!ip->iprouting){			freeb(bp);			return;		}		/* don't forward to source's network */		sr = v6lookup(f, h->src, nil);		r = v6lookup(f, h->dst, nil); 		if(r == nil || sr == r){			ip->stats[OutDiscards]++;			freeblist(bp);			return;		} 		/* don't forward if packet has timed out */		hop = h->ttl;		if(hop < 1) {			ip->stats[InHdrErrors]++;			icmpttlexceeded6(f, ifc, bp);			freeblist(bp);			return;		} 		/* process headers & reassemble if the interface expects it */		bp = procxtns(ip, bp, r->ifc->reassemble); 		if(bp == nil)			return; 		ip->stats[ForwDatagrams]++;		h = (Ip6hdr *) (bp->rp);		tos = IPV6CLASS(h);		hop = h->ttl;		ipoput6(f, bp, 1, hop-1, tos, nil);		return;	} 	/* reassemble & process headers if needed */	bp = procxtns(ip, bp, 1); 	if(bp == nil)		return; 	h = (Ip6hdr *) (bp->rp);	proto = h->proto;	p = Fsrcvpcol(f, proto);	if(p != nil && p->rcv != nil) {		ip->stats[InDelivers]++;		(*p->rcv)(p, ifc, bp);		return;	} 	ip->stats[InDiscards]++;	ip->stats[InUnknownProtos]++;	freeblist(bp);} /* * ipfragfree6 - copied from ipfragfree4 - assume hold fraglock6 */voidipfragfree6(IP *ip, Fragment6 *frag){	Fragment6 *fl, **l; 	if(frag->blist)		freeblist(frag->blist); 	memset(frag->src, 0, IPaddrlen);	frag->id = 0;	frag->blist = nil; 	l = &ip->flisthead6;	for(fl = *l; fl; fl = fl->next) {		if(fl == frag) {			*l = frag->next;			break;		}		l = &fl->next;	} 	frag->next = ip->fragfree6;	ip->fragfree6 = frag; } /* * ipfragallo6 - copied from ipfragalloc4 */Fragment6*ipfragallo6(IP *ip){	Fragment6 *f; 	while(ip->fragfree6 == nil) {		/* free last entry on fraglist */		for(f = ip->flisthead6; f->next; f = f->next)			;		ipfragfree6(ip, f);	}	f = ip->fragfree6;	ip->fragfree6 = f->next;	f->next = ip->flisthead6;	ip->flisthead6 = f;	f->age = NOW + 30000; 	return f;} static Block*procxtns(IP *ip, Block *bp, int doreasm) {

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