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- #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
- {
- IP6FHDR = 8, /* sizeof(Fraghdr6) */
- };
- #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))
- Block* ip6reassemble(IP*, int, Block*, Ip6hdr*);
- Fragment6* ipfragallo6(IP*);
- void ipfragfree6(IP*, Fragment6*);
- Block* procopts(Block *bp);
- static Block* procxtns(IP *ip, Block *bp, int doreasm);
- int unfraglen(Block *bp, uchar *nexthdr, int setfh);
- int
- ipoput6(Fs *f, Block *bp, int gating, int ttl, int tos, Conv *c)
- {
- int medialen, len, chunk, uflen, flen, seglen, lid, offset, fragoff;
- int morefrags, blklen, rv = 0, tentative;
- uchar *gate, nexthdr;
- Block *xp, *nb;
- Fraghdr6 fraghdr;
- IP *ip;
- Ip6hdr *eh;
- Ipifc *ifc;
- Route *r, *sr;
- 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 %I\n",
- eh->src);
- 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 + IP6HDR < len)
- len = chunk + IP6HDR;
- }
- if(len >= IP_MAX){
- 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 && (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 - IP6HDR);
- ifc->m->bwrite(ifc, bp, V6, gate);
- runlock(ifc);
- poperror();
- return 0;
- }
- if(gating && 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 && 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;
- }
- void
- ipiput6(Fs *f, Ipifc *ifc, Block *bp)
- {
- int hl, hop, tos, notforme, tentative;
- uchar proto;
- uchar v6dst[IPaddrlen];
- IP *ip;
- Ip6hdr *h;
- Proto *p;
- 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){
- freeblist(bp);
- return;
- }
- /* don't forward to link-local destinations */
- if(islinklocal(h->dst) ||
- (isv6mcast(h->dst) && (h->dst[1]&0xF) <= Link_local_scop)){
- ip->stats[OutDiscards]++;
- freeblist(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 && p->rcv) {
- ip->stats[InDelivers]++;
- (*p->rcv)(p, ifc, bp);
- return;
- }
- ip->stats[InDiscards]++;
- ip->stats[InUnknownProtos]++;
- freeblist(bp);
- }
- /*
- * ipfragfree6 - copied from ipfragfree4 - assume hold fraglock6
- */
- void
- ipfragfree6(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)
- {
- int offset;
- uchar proto;
- Ip6hdr *h;
- h = (Ip6hdr *)bp->rp;
- offset = unfraglen(bp, &proto, 0);
- if(proto == FH && doreasm != 0) {
- bp = ip6reassemble(ip, offset, bp, h);
- if(bp == nil)
- return nil;
- offset = unfraglen(bp, &proto, 0);
- }
- if(proto == DOH || offset > IP6HDR)
- bp = procopts(bp);
- return bp;
- }
- /*
- * returns length of "Unfragmentable part", i.e., sum of lengths of ipv6 hdr,
- * hop-by-hop & routing headers if present; *nexthdr is set to nexthdr value
- * of the last header in the "Unfragmentable part"; if setfh != 0, nexthdr
- * field of the last header in the "Unfragmentable part" is set to FH.
- */
- int
- unfraglen(Block *bp, uchar *nexthdr, int setfh)
- {
- uchar *p, *q;
- int ufl, hs;
- p = bp->rp;
- q = p+6; /* proto, = p+sizeof(Ip6hdr.vcf)+sizeof(Ip6hdr.ploadlen) */
- *nexthdr = *q;
- ufl = IP6HDR;
- p += ufl;
- while (*nexthdr == HBH || *nexthdr == RH) {
- *nexthdr = *p;
- hs = ((int)*(p+1) + 1) * 8;
- ufl += hs;
- q = p;
- p += hs;
- }
- if(*nexthdr == FH)
- *q = *p;
- if(setfh)
- *q = FH;
- return ufl;
- }
- Block*
- procopts(Block *bp)
- {
- return bp;
- }
- Block*
- ip6reassemble(IP* ip, int uflen, Block* bp, Ip6hdr* ih)
- {
- int fend, offset, ovlap, len, fragsize, pktposn;
- uint id;
- uchar src[IPaddrlen], dst[IPaddrlen];
- Block *bl, **l, *last, *prev;
- Fraghdr6 *fraghdr;
- Fragment6 *f, *fnext;
- fraghdr = (Fraghdr6 *)(bp->rp + uflen);
- memmove(src, ih->src, IPaddrlen);
- memmove(dst, ih->dst, IPaddrlen);
- id = nhgetl(fraghdr->id);
- offset = nhgets(fraghdr->offsetRM) & ~7;
- /*
- * block lists are too hard, pullupblock into a single block
- */
- if(bp->next){
- bp = pullupblock(bp, blocklen(bp));
- ih = (Ip6hdr *)bp->rp;
- }
- qlock(&ip->fraglock6);
- /*
- * find a reassembly queue for this fragment
- */
- for(f = ip->flisthead6; f; f = fnext){
- fnext = f->next;
- if(ipcmp(f->src, src)==0 && ipcmp(f->dst, dst)==0 && f->id == id)
- break;
- if(f->age < NOW){
- ip->stats[ReasmTimeout]++;
- ipfragfree6(ip, f);
- }
- }
- /*
- * if this isn't a fragmented packet, accept it
- * and get rid of any fragments that might go
- * with it.
- */
- if(nhgets(fraghdr->offsetRM) == 0) { /* 1st frag is also last */
- if(f) {
- ipfragfree6(ip, f);
- ip->stats[ReasmFails]++;
- }
- qunlock(&ip->fraglock6);
- return bp;
- }
- if(bp->base+IPFRAGSZ >= bp->rp){
- bp = padblock(bp, IPFRAGSZ);
- bp->rp += IPFRAGSZ;
- }
- BKFG(bp)->foff = offset;
- BKFG(bp)->flen = nhgets(ih->ploadlen) + IP6HDR - uflen - IP6FHDR;
- /* First fragment allocates a reassembly queue */
- if(f == nil) {
- f = ipfragallo6(ip);
- f->id = id;
- memmove(f->src, src, IPaddrlen);
- memmove(f->dst, dst, IPaddrlen);
- f->blist = bp;
- qunlock(&ip->fraglock6);
- ip->stats[ReasmReqds]++;
- 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);
- qunlock(&ip->fraglock6);
- 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;
- /* move up ih hdrs */
- memmove((*l)->rp + ovlap, (*l)->rp, uflen);
- (*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
- * with the trailing bit of fraghdr->offsetRM[1] set, we're done.
- */
- pktposn = 0;
- for(bl = f->blist; bl && BKFG(bl)->foff == pktposn; bl = bl->next) {
- fraghdr = (Fraghdr6 *)(bl->rp + uflen);
- if((fraghdr->offsetRM[1] & 1) == 0) {
- bl = f->blist;
- /* get rid of frag header in first fragment */
- memmove(bl->rp + IP6FHDR, bl->rp, uflen);
- bl->rp += IP6FHDR;
- len = nhgets(((Ip6hdr*)bl->rp)->ploadlen) - IP6FHDR;
- bl->wp = bl->rp + len + IP6HDR;
- /*
- * Pullup all the fragment headers and
- * return a complete packet
- */
- for(bl = bl->next; bl; bl = bl->next) {
- fragsize = BKFG(bl)->flen;
- len += fragsize;
- bl->rp += uflen + IP6FHDR;
- bl->wp = bl->rp + fragsize;
- }
- bl = f->blist;
- f->blist = nil;
- ipfragfree6(ip, f);
- ih = (Ip6hdr*)bl->rp;
- hnputs(ih->ploadlen, len);
- qunlock(&ip->fraglock6);
- ip->stats[ReasmOKs]++;
- return bl;
- }
- pktposn += BKFG(bl)->flen;
- }
- qunlock(&ip->fraglock6);
- return nil;
- }
|