#include	"u.h"#include	"../port/lib.h"#include	"mem.h"#include	"dat.h"#include	"fns.h"#include	"../port/error.h" #include	"../ip/ip.h" typedef struct Iphdr	Iphdr;typedef struct Fragment	Fragment;typedef struct Ipfrag	Ipfrag; enum{	IPHDR		= 20,		/* sizeof(Iphdr) */	IP_VER		= 0x40,		/* Using IP version 4 */	IP_HLEN		= 0x05,		/* Header length in words */	IP_DF		= 0x4000,	/* Don't fragment */	IP_MF		= 0x2000,	/* More fragments */	IP_MAX		= (32*1024),	/* Maximum Internet packet size */}; struct Iphdr{	uchar	vihl;		/* Version and header length */	uchar	tos;		/* Type of service */	uchar	length[2];	/* packet length */	uchar	id[2];		/* ip->identification */	uchar	frag[2];	/* Fragment information */	uchar	ttl;		/* Time to live */	uchar	proto;		/* Protocol */	uchar	cksum[2];	/* Header checksum */	uchar	src[4];		/* IP source */	uchar	dst[4];		/* IP destination */}; struct Fragment{	Block*	blist;	Fragment* next;	ulong 	src;	ulong 	dst;	ushort	id;	ulong 	age;}; struct Ipfrag{	ushort	foff;	ushort	flen;}; /* 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",}; /* an instance of IP */struct IP{	ulong		stats[Nstats]; 	QLock		fraglock;	Fragment*	flisthead;	Fragment*	fragfree; 	Ref		id;	int		iprouting;			/* true if we route like a gateway */}; #define BLKIP(xp)	((Iphdr*)((xp)->rp))/* * This sleazy macro relies on the media header size being * larger than sizeof(Ipfrag). ipreassemble checks this is true */#define BKFG(xp)	((Ipfrag*)((xp)->base)) ushort		ipcsum(uchar*);Block*		ipreassemble(IP*, int, Block*, Iphdr*);void		ipfragfree(IP*, Fragment*);Fragment*	ipfragallo(IP*); voidip_init(Fs *f){	IP *ip; 	ip = smalloc(sizeof(IP));	initfrag(ip, 100);	f->ip = ip;} voidiprouting(Fs *f, int on){	f->ip->iprouting = on;	if(f->ip->iprouting==0)		f->ip->stats[Forwarding] = 2;	else		f->ip->stats[Forwarding] = 1;	} voidipoput(Fs *f, Block *bp, int gating, int ttl, int tos){	Ipifc *ifc;	uchar *gate;	ulong fragoff;	Block *xp, *nb;	Iphdr *eh, *feh;	int lid, len, seglen, chunk, dlen, blklen, offset, medialen;	Route *r, *sr;	IP *ip; 	ip = f->ip; 	/* Fill out the ip header */	eh = (Iphdr*)(bp->rp); 	ip->stats[OutRequests]++; 	/* Number of uchars in data and ip header to write */	len = blocklen(bp); 	if(gating){		chunk = nhgets(eh->length);		if(chunk > len){			ip->stats[OutDiscards]++;			netlog(f, Logip, "short gated packet\n");			goto free;		}		if(chunk < len)			len = chunk;	}	if(len >= IP_MAX){		ip->stats[OutDiscards]++;		netlog(f, Logip, "exceeded ip max size %V\n", eh->dst);		goto free;	} 	r = v4lookup(f, eh->dst);	if(r == nil){		ip->stats[OutNoRoutes]++;		netlog(f, Logip, "no interface %V\n", eh->dst);		goto free;	} 	ifc = r->ifc;	if(r->type & (Rifc|Runi))		gate = eh->dst;	else	if(r->type & (Rbcast|Rmulti)) {		gate = eh->dst;		sr = v4lookup(f, eh->src);		if(sr != nil && (sr->type & Runi))			ifc = sr->ifc;	}	else		gate = r->v4.gate; 	if(!gating)		eh->vihl = IP_VER|IP_HLEN;	eh->ttl = ttl;	if(!gating)		eh->tos = tos; 	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->maxmtu - ifc->m->hsize;	if(len <= medialen) {		if(!gating)			hnputs(eh->id, incref(&ip->id));		hnputs(eh->length, len);		if(!gating){			eh->frag[0] = 0;			eh->frag[1] = 0;		}		eh->cksum[0] = 0;		eh->cksum[1] = 0;		hnputs(eh->cksum, ipcsum(&eh->vihl)); /*		print("ipoput %V->%V via %V\n", eh->src, eh->dst, gate); /**/		ifc->m->bwrite(ifc, bp, V4, gate);		runlock(ifc);		poperror();		return;	} 	if(eh->frag[0] & (IP_DF>>8)){		ip->stats[FragFails]++;		ip->stats[OutDiscards]++;		netlog(f, Logip, "%V: eh->frag[0] & (IP_DF>>8)\n", eh->dst);		goto raise;	} 	seglen = (medialen - IPHDR) & ~7;	if(seglen < 8){		ip->stats[FragFails]++;		ip->stats[OutDiscards]++;		netlog(f, Logip, "%V seglen < 8\n", eh->dst);		goto raise;	} 	dlen = len - IPHDR;	xp = bp;	if(gating)		lid = nhgets(eh->id);	else		lid = incref(&ip->id); 	offset = IPHDR;	while(xp != nil && offset && offset >= BLEN(xp)) {		offset -= BLEN(xp);		xp = xp->next;	}	xp->rp += offset; 	if(gating)		fragoff = nhgets(eh->frag)<<3;	else		fragoff = 0;	dlen += fragoff;	for(; fragoff < dlen; fragoff += seglen) {		nb = allocb(IPHDR+seglen);		feh = (Iphdr*)(nb->rp); 		memmove(nb->wp, eh, IPHDR);		nb->wp += IPHDR; 		if((fragoff + seglen) >= dlen) {			seglen = dlen - fragoff;			hnputs(feh->frag, fragoff>>3);		}		else				hnputs(feh->frag, (fragoff>>3)|IP_MF); 		hnputs(feh->length, seglen + IPHDR);		hnputs(feh->id, lid); 		/* Copy up the data area */		chunk = seglen;		while(chunk) {			if(!xp) {				ip->stats[OutDiscards]++;				ip->stats[FragFails]++;				freeblist(nb);				netlog(f, Logip, "!xp: chunk %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;		}  		feh->cksum[0] = 0;		feh->cksum[1] = 0;		hnputs(feh->cksum, ipcsum(&feh->vihl));		ifc->m->bwrite(ifc, nb, V4, gate);		ip->stats[FragCreates]++;	}	ip->stats[FragOKs]++;raise:	runlock(ifc);	poperror();free:	freeblist(bp);	} voidinitfrag(IP *ip, int size){	Fragment *fq, *eq; 	ip->fragfree = (Fragment*)malloc(sizeof(Fragment) * size);	if(ip->fragfree == nil)		panic("initfrag"); 	eq = &ip->fragfree[size];	for(fq = ip->fragfree; fq < eq; fq++)		fq->next = fq+1; 	ip->fragfree[size-1].next = nil;} #define DBG(x)	if((logmask & Logipmsg) && (iponly == 0 || x == iponly))netlog voidipiput(Fs *f, Ipifc *ifc, Block *bp){	int hl;	Iphdr *h;	Proto *p;	ushort frag;	int notforme;	uchar *dp, v6dst[IPaddrlen];	IP *ip;	Route *r, *sr; 	ip = f->ip;	ip->stats[InReceives]++; //	h = (Iphdr *)(bp->rp);//	DBG(nhgetl(h->src))(Logipmsg, "ipiput %V %V len %d proto %d\n",//				h->src, h->dst, BLEN(bp), h->proto); 	/*	 *  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 < IPHDR)			hl = IPHDR;		if(hl > 64)			hl = 64;		bp = pullupblock(bp, hl);		if(bp == nil)			return;	}	h = (Iphdr *)(bp->rp); 	/* dump anything that whose header doesn't checksum */	if(ipcsum(&h->vihl)) {		ip->stats[InHdrErrors]++;		netlog(f, Logip, "ip: checksum error %V\n", h->src);		freeblist(bp);		return;	} 	v4tov6(v6dst, h->dst);	notforme = ipforme(f, v6dst) == 0; 	/* Check header length and version */	if(h->vihl != (IP_VER|IP_HLEN)) {		hl = (h->vihl&0xF)<<2;		if((h->vihl&0xF0) != IP_VER || hl < (IP_HLEN<<2)) {			ip->stats[InHdrErrors]++;			netlog(f, Logip, "ip: %V bad hivl %ux\n", h->src, h->vihl);			freeblist(bp);			return;		}		/* If this is not routed strip off the options */		if(notforme == 0) {			dp = bp->rp + (hl - (IP_HLEN<<2));			memmove(dp, h, IP_HLEN<<2);			bp->rp = dp;			h = (Iphdr *)(bp->rp);			h->vihl = (IP_VER|IP_HLEN);		}	} 	/* route */	if(notforme) {		if(!ip->iprouting){			freeb(bp);			return;		} 		/* don't forward to source's network */		sr = v4lookup(f, h->src);		r = v4lookup(f, h->dst);		if(r == nil || sr == r){			ip->stats[OutDiscards]++;			freeblist(bp);			return;		} 		/* don't forward if packet has timed out */		if(h->ttl <= 1){			ip->stats[InHdrErrors]++;			icmpttlexceeded(f, ifc, bp);			freeblist(bp);			return;		}				/* reassemble if the interface expects it */		if(r->ifc->reassemble){			frag = nhgets(h->frag);			if(frag) {				h->tos = 0;				if(frag & IP_MF)					h->tos = 1;				bp = ipreassemble(ip, frag, bp, h);				if(bp == nil)					return;				h = (Iphdr *)(bp->rp);			}		} 		ip->stats[ForwDatagrams]++;		ipoput(f, bp, 1, h->ttl - 1, h->tos); 		return;	} 	/* reassemble */	frag = nhgets(h->frag);	if(frag) {		h->tos = 0;		if(frag & IP_MF)			h->tos = 1;		bp = ipreassemble(ip, frag, bp, h);		if(bp == nil)			return;		h = (Iphdr *)(bp->rp);	} 	p = Fsrcvpcol(f, h->proto);	if(p != nil && p->rcv != nil) {		ip->stats[InDelivers]++;		(*p->rcv)(p, ifc, bp);		return;	}	ip->stats[InDiscards]++;	ip->stats[InUnknownProtos]++;	freeblist(bp);} intipstats(Fs *f, char *buf, int len){	IP *ip;	char *p, *e;	int i; 	ip = f->ip;	ip->stats[DefaultTTL] = MAXTTL; 	p = buf;	e = p+len;	for(i = 0; i < Nstats; i++)		p = seprint(p, e, "%s: %lud\n", statnames[i], ip->stats[i]);	return p - buf;} Block*ipreassemble(IP *ip, int offset, Block *bp, Iphdr *ih){	int fend;	ushort id;

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