#include	"u.h"#include	"../port/lib.h"#include	"mem.h"#include	"dat.h"#include	"fns.h"#include	"../port/error.h" #include	"ip.h" typedef struct Ip4hdr		Ip4hdr;typedef struct IP		IP;typedef struct Fragment4	Fragment4;typedef struct Fragment6	Fragment6;typedef struct Ipfrag		Ipfrag; 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		= 64*1024,	/* Maximum Internet packet size */}; #define BLKIPVER(xp)	(((Ip4hdr*)((xp)->rp))->vihl&0xF0) struct Ip4hdr{	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 */}; /* MIB II counters */enum{	Forwarding,	DefaultTTL,	InReceives,	InHdrErrors,	InAddrErrors,	ForwDatagrams,	InUnknownProtos,	InDiscards,	InDelivers,	OutRequests,	OutDiscards,	OutNoRoutes,	ReasmTimeout,	ReasmReqds,	ReasmOKs,	ReasmFails,	FragOKs,	FragFails,	FragCreates, 	Nstats,}; 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 */}; 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",}; #define BLKIP(xp)	((Ip4hdr*)((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*		ip4reassemble(IP*, int, Block*, Ip4hdr*);void		ipfragfree4(IP*, Fragment4*);Fragment4*	ipfragallo4(IP*);  voidip_init_6(Fs *f){	V6params *v6p; 	v6p = smalloc(sizeof(V6params));		v6p->rp.mflag		= 0;		// default not managed	v6p->rp.oflag		= 0;	v6p->rp.maxraint	= 600000;	// millisecs	v6p->rp.minraint	= 200000;	v6p->rp.linkmtu		= 0;		// no mtu sent	v6p->rp.reachtime	= 0;	v6p->rp.rxmitra		= 0;	v6p->rp.ttl		= MAXTTL;	v6p->rp.routerlt	= 3*(v6p->rp.maxraint);	 	v6p->hp.rxmithost	= 1000;		// v6 RETRANS_TIMER 	v6p->cdrouter 		= -1; 	f->v6p			= v6p; } voidinitfrag(IP *ip, int size){	Fragment4 *fq4, *eq4;	Fragment6 *fq6, *eq6; 	ip->fragfree4 = (Fragment4*)malloc(sizeof(Fragment4) * size);	if(ip->fragfree4 == nil)		panic("initfrag"); 	eq4 = &ip->fragfree4[size];	for(fq4 = ip->fragfree4; fq4 < eq4; fq4++)		fq4->next = fq4+1; 	ip->fragfree4[size-1].next = nil; 	ip->fragfree6 = (Fragment6*)malloc(sizeof(Fragment6) * size);	if(ip->fragfree6 == nil)		panic("initfrag"); 	eq6 = &ip->fragfree6[size];	for(fq6 = ip->fragfree6; fq6 < eq6; fq6++)		fq6->next = fq6+1; 	ip->fragfree6[size-1].next = nil;} voidip_init(Fs *f){	IP *ip; 	ip = smalloc(sizeof(IP));	initfrag(ip, 100);	f->ip = ip; 	ip_init_6(f);} 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;	} intipoput4(Fs *f, Block *bp, int gating, int ttl, int tos, Conv *c){	Ipifc *ifc;	uchar *gate;	ulong fragoff;	Block *xp, *nb;	Ip4hdr *eh, *feh;	int lid, len, seglen, chunk, dlen, blklen, offset, medialen;	Route *r, *sr;	IP *ip;	int rv = 0; 	ip = f->ip; 	/* Fill out the ip header */	eh = (Ip4hdr*)(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, c);	if(r == nil){		ip->stats[OutNoRoutes]++;		netlog(f, Logip, "no interface %V\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 = v4lookup(f, eh->src, nil);		if(sr != nil && (sr->type & Runi))			ifc = sr->ifc;	}	else		gate = r->v4.gate; 	if(!gating)		eh->vihl = IP_VER4|IP_HLEN4;	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->maxtu - ifc->m->hsize;	if(len <= medialen) {		if(!gating)			hnputs(eh->id, incref(&ip->id4));		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));		ifc->m->bwrite(ifc, bp, V4, gate);		runlock(ifc);		poperror();		return 0;	} if((eh->frag[0] & (IP_DF>>8)) && !gating) print("%V: DF set\n", eh->dst); 	if(eh->frag[0] & (IP_DF>>8)){		ip->stats[FragFails]++;		ip->stats[OutDiscards]++;		icmpcantfrag(f, bp, medialen);		netlog(f, Logip, "%V: eh->frag[0] & (IP_DF>>8)\n", eh->dst);		goto raise;	} 	seglen = (medialen - IP4HDR) & ~7;	if(seglen < 8){		ip->stats[FragFails]++;		ip->stats[OutDiscards]++;		netlog(f, Logip, "%V seglen < 8\n", eh->dst);		goto raise;	} 	dlen = len - IP4HDR;	xp = bp;	if(gating)		lid = nhgets(eh->id);	else		lid = incref(&ip->id4); 	offset = IP4HDR;	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(IP4HDR+seglen);		feh = (Ip4hdr*)(nb->rp); 		memmove(nb->wp, eh, IP4HDR);		nb->wp += IP4HDR; 		if((fragoff + seglen) >= dlen) {			seglen = dlen - fragoff;			hnputs(feh->frag, fragoff>>3);		}		else				hnputs(feh->frag, (fragoff>>3)|IP_MF); 		hnputs(feh->length, seglen + IP4HDR);		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);	return rv;} voidipiput4(Fs *f, Ipifc *ifc, Block *bp){	int hl;	int hop, tos, proto, olen;	Ip4hdr *h;	Proto *p;	ushort frag;	int notforme;	uchar *dp, v6dst[IPaddrlen];	IP *ip;	Route *r; 	if(BLKIPVER(bp) != IP_VER4) {		ipiput6(f, ifc, bp);		return;	} 	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 < IP4HDR)			hl = IP4HDR;		if(hl > 64)			hl = 64;		bp = pullupblock(bp, hl);		if(bp == nil)			return;	} 	h = (Ip4hdr*)(bp->rp); 	/* dump anything that whose header doesn't checksum */	if((bp->flag & Bipck) == 0 && 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&0x0F) != IP_HLEN4) {		hl = (h->vihl&0xF)<<2;		if(hl < (IP_HLEN4<<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) {			olen = nhgets(h->length);			dp = bp->rp + (hl - (IP_HLEN4<<2));			memmove(dp, h, IP_HLEN4<<2);			bp->rp = dp;			h = (Ip4hdr*)(bp->rp);			h->vihl = (IP_VER4|IP_HLEN4);			hnputs(h->length, olen-hl+(IP_HLEN4<<2));		}	} 	/* route */	if(notforme) {		Conv conv; 		if(!ip->iprouting){			freeb(bp);			return;		} 		/* don't forward to source's network */		conv.r = nil;		r = v4lookup(f, h->dst, &conv);		if(r == nil || r->ifc == ifc){			ip->stats[OutDiscards]++;			freeblist(bp);			return;		} 		/* don't forward if packet has timed out */		hop = h->ttl;		if(hop < 1) {			ip->stats[InHdrErrors]++;			icmpttlexceeded(f, ifc->lifc->local, bp);			freeblist(bp);

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