2003/0216/ip/ip.c (diff list | history)

ip/ip.c on 1997/0327
1997/0327		#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h"
2002/0507		#include "ip.h"
1997/0327
2002/0507		typedef struct Ip4hdr Ip4hdr; typedef struct IP IP; typedef struct Fragment4 Fragment4; typedef struct Fragment6 Fragment6; typedef struct Ipfrag Ipfrag;
1997/0327		enum {
2002/0507		IP4HDR = 20, /* sizeof(Ip4hdr) */ IP6HDR = 40, /* sizeof(Ip6hdr) */ IP_HLEN4 = 0x05, /* Header length in words */
1997/0327		IP_DF = 0x4000, /* Don't fragment */ IP_MF = 0x2000, /* More fragments */
2002/0507		IP6FHDR = 8, /* sizeof(Fraghdr6) */
2002/0615		IP_MAX = 64*1024, /* Maximum Internet packet size */
1997/0327		};
2002/0507		#define BLKIPVER(xp) (((Ip4hdr*)((xp)->rp))->vihl&0xF0) struct Ip4hdr
1997/0327		{
1998/0306		uchar vihl; /* Version and header length */ uchar tos; /* Type of service */ uchar length[2]; /* packet length */
1998/0313		uchar id[2]; /* ip->identification */
1998/0306		uchar frag[2]; /* Fragment information */
2002/0507		uchar ttl; /* Time to live */
1998/0306		uchar proto; /* Protocol */ uchar cksum[2]; /* Header checksum */
1998/0313		uchar src[4]; /* IP source */ uchar dst[4]; /* IP destination */
1997/0327		};
1998/0313		/* MIB II counters */
2000/0706		enum
1998/0313		{
2000/0706		Forwarding, DefaultTTL, InReceives, InHdrErrors, InAddrErrors, ForwDatagrams, InUnknownProtos, InDiscards, InDelivers, OutRequests, OutDiscards, OutNoRoutes, ReasmTimeout, ReasmReqds, ReasmOKs, ReasmFails, FragOKs, FragFails, FragCreates, Nstats,
1998/0313		};
1997/0327
2002/0507		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 */ };
2000/0706		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", };
2002/0507		#define BLKIP(xp) ((Ip4hdr*)((xp)->rp))
1997/0327		/* * 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))
1998/0313		ushort ipcsum(uchar*);
2002/0507		Block* ip4reassemble(IP*, int, Block*, Ip4hdr*); void ipfragfree4(IP*, Fragment4*); Fragment4* ipfragallo4(IP*);
1998/0313
2002/0507
1998/0313		void
2002/0507		ip_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; } void initfrag(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; } void
1998/0313		ip_init(Fs *f)
1997/0916		{
1998/0313		IP *ip;
1997/0916
1998/0313		ip = smalloc(sizeof(IP)); initfrag(ip, 100); f->ip = ip;
2002/0507		ip_init_6(f);
1998/0313		}
1997/0327		void
1998/0314		iprouting(Fs *f, int on) { f->ip->iprouting = on;
1998/0813		if(f->ip->iprouting==0)
2000/0706		f->ip->stats[Forwarding] = 2;
1998/0813		else
2000/0706		f->ip->stats[Forwarding] = 1;
1998/0314		} void
2002/0507		ipoput4(Fs *f, Block *bp, int gating, int ttl, int tos)
1997/0327		{
1998/0306		Ipifc *ifc; uchar *gate;
2001/1007		ulong fragoff;
1997/0327		Block *xp, *nb;
2002/0507		Ip4hdr *eh, *feh;
1997/0327		int lid, len, seglen, chunk, dlen, blklen, offset, medialen;
1998/0313		Route *r, *sr; IP *ip;
2003/0214		Proto *pr;
1997/0327
1998/0313		ip = f->ip;
1997/0327		/* Fill out the ip header */
2002/0507		eh = (Ip4hdr*)(bp->rp);
1997/0327
2000/0706		ip->stats[OutRequests]++;
1998/0313
1998/0306		/* Number of uchars in data and ip header to write */
1997/0327		len = blocklen(bp);
1998/0313
1997/0327		if(gating){ chunk = nhgets(eh->length); if(chunk > len){
2000/0706		ip->stats[OutDiscards]++;
1998/0313		netlog(f, Logip, "short gated packet\n");
1998/0308		goto free;
1997/0327		} if(chunk < len) len = chunk; }
1998/0306		if(len >= IP_MAX){
2000/0706		ip->stats[OutDiscards]++;
1998/0313		netlog(f, Logip, "exceeded ip max size %V\n", eh->dst);
1998/0308		goto free;
1997/0327		}
1998/0313		r = v4lookup(f, eh->dst);
1998/0306		if(r == nil){
2000/0706		ip->stats[OutNoRoutes]++;
1998/0313		netlog(f, Logip, "no interface %V\n", eh->dst);
2003/0214		if(!gating){
2003/0216		freeblist(bp); print("ipoput4: no route\n");
2003/0214		error("no route"); }
1998/0308		goto free;
1997/0327		}
1998/0313		ifc = r->ifc; if(r->type & (Rifc|Runi))
1998/0306		gate = eh->dst; else
1998/0313		if(r->type & (Rbcast|Rmulti)) { gate = eh->dst; sr = v4lookup(f, eh->src); if(sr != nil && (sr->type & Runi)) ifc = sr->ifc; } else
1998/0306		gate = r->v4.gate;
1998/0313
1999/10041		if(!gating)
2002/0507		eh->vihl = IP_VER4|IP_HLEN4;
1999/10041		eh->ttl = ttl;
2001/0430		if(!gating) eh->tos = tos;
1997/0327
1999/0302		if(!canrlock(ifc)) goto free;
1998/0307		if(waserror()){ runlock(ifc); nexterror(); } if(ifc->m == nil) goto raise;
1997/0327		/* If we dont need to fragment just send it */
2003/0209		medialen = ifc->maxtu - ifc->m->hsize;
1997/0327		if(len <= medialen) { if(!gating)
2002/0507		hnputs(eh->id, incref(&ip->id4));
1997/0327		hnputs(eh->length, len);
2001/0430		if(!gating){ eh->frag[0] = 0; eh->frag[1] = 0; }
1997/0327		eh->cksum[0] = 0; eh->cksum[1] = 0; hnputs(eh->cksum, ipcsum(&eh->vihl));
1998/0306		ifc->m->bwrite(ifc, bp, V4, gate);
1998/0307		runlock(ifc); poperror();
1997/0327		return; }
2002/1204		if((eh->frag[0] & (IP_DF>>8)) && !gating) print("%V: DF set\n", eh->dst);
1997/0327		if(eh->frag[0] & (IP_DF>>8)){
2000/0706		ip->stats[FragFails]++; ip->stats[OutDiscards]++;
2002/1207		icmpcantfrag(f, bp, medialen);
1998/0313		netlog(f, Logip, "%V: eh->frag[0] & (IP_DF>>8)\n", eh->dst);
1997/0327		goto raise; }
2002/0507		seglen = (medialen - IP4HDR) & ~7;
1997/0327		if(seglen < 8){
2000/0706		ip->stats[FragFails]++; ip->stats[OutDiscards]++;
1998/0313		netlog(f, Logip, "%V seglen < 8\n", eh->dst);
1997/0327		goto raise; }
2002/0507		dlen = len - IP4HDR;
1997/0327		xp = bp; if(gating) lid = nhgets(eh->id); else
2002/0507		lid = incref(&ip->id4);
1997/0327
2002/0507		offset = IP4HDR;
1997/0327		while(xp != nil && offset && offset >= BLEN(xp)) { offset -= BLEN(xp); xp = xp->next; } xp->rp += offset;
2001/0430		if(gating)
2001/1007		fragoff = nhgets(eh->frag)<<3;
2001/0430		else fragoff = 0; dlen += fragoff; for(; fragoff < dlen; fragoff += seglen) {
2002/0507		nb = allocb(IP4HDR+seglen); feh = (Ip4hdr*)(nb->rp);
1997/0327
2002/0507		memmove(nb->wp, eh, IP4HDR); nb->wp += IP4HDR;
1997/0327		if((fragoff + seglen) >= dlen) { seglen = dlen - fragoff; hnputs(feh->frag, fragoff>>3); } else hnputs(feh->frag, (fragoff>>3)|IP_MF);
2002/0507		hnputs(feh->length, seglen + IP4HDR);
1997/0327		hnputs(feh->id, lid); /* Copy up the data area */ chunk = seglen; while(chunk) { if(!xp) {
2000/0706		ip->stats[OutDiscards]++; ip->stats[FragFails]++;
1997/0327		freeblist(nb);
1998/0313		netlog(f, Logip, "!xp: chunk %d\n", chunk);
1997/0327		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;
1998/0313		}
1997/0327		feh->cksum[0] = 0; feh->cksum[1] = 0; hnputs(feh->cksum, ipcsum(&feh->vihl));
1998/0306		ifc->m->bwrite(ifc, nb, V4, gate);
2000/0706		ip->stats[FragCreates]++;
1997/0327		}
2000/0706		ip->stats[FragOKs]++;
1997/0327		raise:
1998/0307		runlock(ifc); poperror();
1998/0308		free:
1997/0327		freeblist(bp); } void
2002/0507		ipiput4(Fs *f, Ipifc *ifc, Block *bp)
1997/0327		{
1998/0313		int hl;
2002/0507		int hop, tos, proto, olen; Ip4hdr *h;
1997/0327		Proto *p; ushort frag; int notforme;
1998/0313		uchar *dp, v6dst[IPaddrlen]; IP *ip;
1998/1209		Route *r, *sr;
1997/0327
2002/0507		if(BLKIPVER(bp) != IP_VER4) { ipiput6(f, ifc, bp); return; }
1998/0313		ip = f->ip;
2000/0706		ip->stats[InReceives]++;
1998/0313
1998/0326		/*
1998/0331		* Ensure we have all the header info in the first
1998/0326		* 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);
2002/0507		if(hl < IP4HDR) hl = IP4HDR;
1998/0326		if(hl > 64) hl = 64; bp = pullupblock(bp, hl);
1997/0327		if(bp == nil) return; }
2002/0507		h = (Ip4hdr*)(bp->rp);
1998/0306		/* dump anything that whose header doesn't checksum */
2003/0213		if((bp->flag & Bipck) == 0 && ipcsum(&h->vihl)) {
2000/0706		ip->stats[InHdrErrors]++;
1998/1208		netlog(f, Logip, "ip: checksum error %V\n", h->src);
1997/0327		freeblist(bp); return; }
1998/0306		v4tov6(v6dst, h->dst);
1998/0313		notforme = ipforme(f, v6dst) == 0; /* Check header length and version */
2002/0507		if((h->vihl&0x0F) != IP_HLEN4) {
1998/0313		hl = (h->vihl&0xF)<<2;
2002/0507		if(hl < (IP_HLEN4<<2)) {
2000/0706		ip->stats[InHdrErrors]++;
1998/0313		netlog(f, Logip, "ip: %V bad hivl %ux\n", h->src, h->vihl); freeblist(bp); return; }
2002/0507		/* If this is not routed strip off the options */
1998/0313		if(notforme == 0) {
2002/0424		olen = nhgets(h->length);
2002/0507		dp = bp->rp + (hl - (IP_HLEN4<<2)); memmove(dp, h, IP_HLEN4<<2);
1998/0313		bp->rp = dp;
2002/0507		h = (Ip4hdr*)(bp->rp); h->vihl = (IP_VER4|IP_HLEN4); hnputs(h->length, olen-hl+(IP_HLEN4<<2));
1998/0313		} } /* route */
1998/0306		if(notforme) {
1998/1209		if(!ip->iprouting){
2000/0220		freeb(bp);
1998/1209		return; } /* don't forward to source's network */ sr = v4lookup(f, h->src); r = v4lookup(f, h->dst);
2002/0507
1998/1209		if(r == nil || sr == r){
2000/0706		ip->stats[OutDiscards]++;
1998/1209		freeblist(bp); return; } /* don't forward if packet has timed out */
2002/0507		hop = h->ttl; if(hop < 1) {
2000/0706		ip->stats[InHdrErrors]++;
2002/0507		icmpttlexceeded(f, ifc->lifc->local, bp);
1998/1209		freeblist(bp); return; }
2002/0507
2001/1117		/* 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;
2002/0507		bp = ip4reassemble(ip, frag, bp, h);
2001/1117		if(bp == nil) return;
2002/0507		h = (Ip4hdr*)(bp->rp);
2001/1117		} }
1998/1209
2000/0706		ip->stats[ForwDatagrams]++;
2002/0507		tos = h->tos; hop = h->ttl; ipoput4(f, bp, 1, hop - 1, tos);
1998/0306		return; }
1997/0327		frag = nhgets(h->frag); if(frag) { h->tos = 0; if(frag & IP_MF) h->tos = 1;
2002/0507		bp = ip4reassemble(ip, frag, bp, h);
1997/0327		if(bp == nil) return;
2002/0507		h = (Ip4hdr*)(bp->rp);
1997/0327		}
2002/1207		/* don't let any frag info go up the stack */ h->frag[0] = 0; h->frag[1] = 0;
1997/0327
2002/0507		proto = h->proto; p = Fsrcvpcol(f, proto);
1998/0313		if(p != nil && p->rcv != nil) {
2000/0706		ip->stats[InDelivers]++;
2001/0623		(*p->rcv)(p, ifc, bp);
1998/0313		return; }
2000/0706		ip->stats[InDiscards]++; ip->stats[InUnknownProtos]++;
1998/0313		freeblist(bp);
1997/0327		} int
1998/0313		ipstats(Fs *f, char *buf, int len)
1997/0327		{
1998/0313		IP *ip;
2000/0706		char *p, *e; int i;
1997/0327
1998/0313		ip = f->ip;
2000/0706		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;
1997/0327		} Block*
2002/0507		ip4reassemble(IP *ip, int offset, Block *bp, Ip4hdr *ih)
1997/0327		{ int fend; ushort id;
2002/0507		Fragment4 *f, *fnext;
1998/0306		ulong src, dst;
1997/0327		Block *bl, **l, *last, *prev; int ovlap, len, fragsize, pktposn;
1998/0313		src = nhgetl(ih->src); dst = nhgetl(ih->dst); id = nhgets(ih->id);
1997/0327		/* * block lists are too hard, pullupblock into a single block */ if(bp->next){ bp = pullupblock(bp, blocklen(bp));
2002/0507		ih = (Ip4hdr*)(bp->rp);
1997/0327		}
2002/0507		qlock(&ip->fraglock4);
1997/0327		/* * find a reassembly queue for this fragment */
2002/0507		for(f = ip->flisthead4; f; f = fnext){ fnext = f->next; /* because ipfragfree4 changes the list */
1997/0327		if(f->src == src && f->dst == dst && f->id == id) break;
2002/0710		if(f->age < NOW){
2000/0706		ip->stats[ReasmTimeout]++;
2002/0507		ipfragfree4(ip, f);
1997/0916		}
1997/0327		} /* * if this isn't a fragmented packet, accept it * and get rid of any fragments that might go * with it. */
1998/0313		if(!ih->tos && (offset & ~(IP_MF|IP_DF)) == 0) { if(f != nil) {
2002/0507		ipfragfree4(ip, f);
2000/0706		ip->stats[ReasmFails]++;
1998/0313		}
2002/0507		qunlock(&ip->fraglock4);
1997/0327		return bp; }
1997/0504		if(bp->base+sizeof(Ipfrag) >= bp->rp){ bp = padblock(bp, sizeof(Ipfrag)); bp->rp += sizeof(Ipfrag); }
1997/0327		BKFG(bp)->foff = offset<<3;
2002/0507		BKFG(bp)->flen = nhgets(ih->length)-IP4HDR;
1997/0327		/* First fragment allocates a reassembly queue */ if(f == nil) {
2002/0507		f = ipfragallo4(ip);
1997/0327		f->id = id; f->src = src; f->dst = dst; f->blist = bp;
2002/0507		qunlock(&ip->fraglock4);
2000/0706		ip->stats[ReasmReqds]++;
1997/0327		return nil; } /* * find the new fragment's position in the queue */ prev = nil; l = &f->blist; bl = f->blist; while(bl != nil && BKFG(bp)->foff > BKFG(bl)->foff) { prev = bl; l = &bl->next; bl = bl->next; } /* Check overlap of a previous fragment - trim away as necessary */ if(prev) { ovlap = BKFG(prev)->foff + BKFG(prev)->flen - BKFG(bp)->foff; if(ovlap > 0) { if(ovlap >= BKFG(bp)->flen) { freeblist(bp);
2002/0507		qunlock(&ip->fraglock4);
1997/0327		return nil; } BKFG(prev)->flen -= ovlap; } } /* Link onto assembly queue */ bp->next = *l; *l = bp; /* Check to see if succeeding segments overlap */ if(bp->next) { l = &bp->next; fend = BKFG(bp)->foff + BKFG(bp)->flen; /* Take completely covered segments out */ while(*l) { ovlap = fend - BKFG(*l)->foff; if(ovlap <= 0) break; if(ovlap < BKFG(*l)->flen) { BKFG(*l)->flen -= ovlap; BKFG(*l)->foff += ovlap;
1998/0313		/* move up ih hdrs */
2002/0507		memmove((*l)->rp + ovlap, (*l)->rp, IP4HDR);
1997/0327		(*l)->rp += ovlap; break; } last = (*l)->next; (*l)->next = nil; freeblist(*l); *l = last; } } /* * look for a complete packet. if we get to a fragment * without IP_MF set, we're done. */ pktposn = 0; for(bl = f->blist; bl; bl = bl->next) { if(BKFG(bl)->foff != pktposn) break; if((BLKIP(bl)->frag[0]&(IP_MF>>8)) == 0) { bl = f->blist; len = nhgets(BLKIP(bl)->length); bl->wp = bl->rp + len; /* Pullup all the fragment headers and * return a complete packet */ for(bl = bl->next; bl; bl = bl->next) { fragsize = BKFG(bl)->flen; len += fragsize;
2002/0507		bl->rp += IP4HDR;
1997/0327		bl->wp = bl->rp + fragsize; } bl = f->blist; f->blist = nil;
2002/0507		ipfragfree4(ip, f);
1998/0313		ih = BLKIP(bl); hnputs(ih->length, len);
2002/0507		qunlock(&ip->fraglock4);
2000/0706		ip->stats[ReasmOKs]++;
1997/0327		return bl; } pktposn += BKFG(bl)->flen; }
2002/0507		qunlock(&ip->fraglock4);
1997/0327		return nil; } /*
2002/0507		* ipfragfree4 - Free a list of fragments - assume hold fraglock4
1997/0327		*/ void
2002/0507		ipfragfree4(IP *ip, Fragment4 *frag)
1997/0327		{
2002/0507		Fragment4 *fl, **l;
1997/0327		if(frag->blist) freeblist(frag->blist); frag->src = 0; frag->id = 0; frag->blist = nil;
2002/0507		l = &ip->flisthead4;
1997/0327		for(fl = *l; fl; fl = fl->next) { if(fl == frag) { *l = frag->next; break; } l = &fl->next; }
2002/0507		frag->next = ip->fragfree4; ip->fragfree4 = frag;
1997/0327		} /*
2002/0507		* ipfragallo4 - allocate a reassembly queue - assume hold fraglock4
1997/0327		*/
2002/0507		Fragment4 * ipfragallo4(IP *ip)
1997/0327		{
2002/0507		Fragment4 *f;
1997/0327
2002/0507		while(ip->fragfree4 == nil) {
1997/0529		/* free last entry on fraglist */
2002/0507		for(f = ip->flisthead4; f->next; f = f->next)
1997/0529		;
2002/0507		ipfragfree4(ip, f);
1997/0327		}
2002/0507		f = ip->fragfree4; ip->fragfree4 = f->next; f->next = ip->flisthead4; ip->flisthead4 = f;
2002/0710		f->age = NOW + 30000;
1997/0327		return f; } ushort
1998/0306		ipcsum(uchar *addr)
1997/0327		{ int len; ulong sum; sum = 0; len = (addr[0]&0xf)<<2; while(len > 0) { sum += addr[0]<<8 | addr[1] ; len -= 2; addr += 2; } sum = (sum & 0xffff) + (sum >> 16); sum = (sum & 0xffff) + (sum >> 16); return (sum^0xffff);
2001/1117		}