devip: fix fragment forwarding
unfraglen() had the side effect that it would always copy the nexthdr field from the fragment header to the previous nexthdr field. this is fine when we reassemble packets but breaks fragments that we want to just forward unchanged.front
cinap_lenrek
parent
fa97c3dd10
commit
a1fceabd5b
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@ -8,17 +8,12 @@
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#include "ip.h"
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#include "ipv6.h"
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enum
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{
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IP6FHDR = 8, /* sizeof(Fraghdr6) */
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};
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static Block* ip6reassemble(IP*, int, Block*);
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static Fragment6* ipfragallo6(IP*);
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static void ipfragfree6(IP*, Fragment6*);
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static Block* procopts(Block *bp);
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static Block* procxtns(IP *ip, Block *bp, int doreasm);
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static int unfraglen(Block *bp, uchar *nexthdr, int setfh);
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static int unfraglen(Block *bp, uchar *nexthdr, int setfh, int popfh);
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void
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ip_init_6(Fs *f)
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@ -122,8 +117,14 @@ ipoput6(Fs *f, Block *bp, int gating, int ttl, int tos, Routehint *rh)
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}
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/* start v6 fragmentation */
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uflen = unfraglen(bp, &nexthdr, 1);
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if(uflen < 0 || uflen > medialen) {
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uflen = unfraglen(bp, &nexthdr, 1, 0);
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if(uflen < IP6HDR || nexthdr == FH) {
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ip->stats[FragFails]++;
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ip->stats[OutDiscards]++;
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netlog(f, Logip, "%I -> %I: fragment header botch\n", eh->src, eh->dst);
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goto raise;
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}
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if(uflen > medialen) {
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ip->stats[FragFails]++;
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ip->stats[OutDiscards]++;
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netlog(f, Logip, "%I -> %I: unfragmentable part too big: %d\n", eh->src, eh->dst, uflen);
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@ -210,7 +211,6 @@ void
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ipiput6(Fs *f, Ipifc *ifc, Block *bp)
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{
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int hl, len, hop, tos;
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uchar proto;
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IP *ip;
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Ip6hdr *h;
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Proto *p;
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@ -301,8 +301,7 @@ ipiput6(Fs *f, Ipifc *ifc, Block *bp)
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return;
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h = (Ip6hdr*)bp->rp;
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proto = h->proto;
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p = Fsrcvpcol(f, proto);
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p = Fsrcvpcol(f, h->proto);
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if(p != nil && p->rcv != nil) {
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ip->stats[InDelivers]++;
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(*p->rcv)(p, ifc, bp);
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@ -323,15 +322,15 @@ ipfragfree6(IP *ip, Fragment6 *frag)
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{
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Fragment6 *fl, **l;
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if(frag->blist)
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if(frag->blist != nil)
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freeblist(frag->blist);
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memset(frag->src, 0, IPaddrlen);
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frag->id = 0;
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frag->blist = nil;
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frag->id = 0;
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memset(frag->src, 0, IPaddrlen);
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memset(frag->dst, 0, IPaddrlen);
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l = &ip->flisthead6;
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for(fl = *l; fl; fl = fl->next) {
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for(fl = *l; fl != nil; fl = fl->next) {
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if(fl == frag) {
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*l = frag->next;
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break;
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@ -353,7 +352,7 @@ ipfragallo6(IP *ip)
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while(ip->fragfree6 == nil) {
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/* free last entry on fraglist */
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for(f = ip->flisthead6; f->next; f = f->next)
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for(f = ip->flisthead6; f->next != nil; f = f->next)
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;
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ipfragfree6(ip, f);
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}
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@ -372,16 +371,18 @@ procxtns(IP *ip, Block *bp, int doreasm)
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uchar proto;
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int offset;
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offset = unfraglen(bp, &proto, 0);
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if(offset >= 0 && proto == FH && doreasm != 0) {
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offset = unfraglen(bp, &proto, 0, doreasm);
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if(offset >= IP6HDR && proto == FH && doreasm) {
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bp = ip6reassemble(ip, offset, bp);
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if(bp == nil)
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return nil;
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offset = unfraglen(bp, &proto, 0);
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offset = unfraglen(bp, &proto, 0, 0);
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if(proto == FH)
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offset = -1;
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}
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if(offset < 0){
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if(offset < IP6HDR){
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ip->stats[InHdrErrors]++;
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ip->stats[InDiscards]++;
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freeblist(bp);
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return nil;
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}
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@ -395,10 +396,12 @@ procxtns(IP *ip, Block *bp, int doreasm)
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* hop-by-hop & routing headers if present; *nexthdr is set to nexthdr value
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* of the last header in the "Unfragmentable part"; if setfh != 0, nexthdr
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* field of the last header in the "Unfragmentable part" is set to FH.
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* returns -1 on error.
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* When the last header is a fragment header and popfh != 0 then set
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* the nexthdr value of the previous header to the nexthdr value of the
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* fragment header. returns -1 on error.
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*/
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static int
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unfraglen(Block *bp, uchar *nexthdr, int setfh)
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unfraglen(Block *bp, uchar *nexthdr, int setfh, int popfh)
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{
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uchar *e, *p, *q;
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@ -417,9 +420,10 @@ unfraglen(Block *bp, uchar *nexthdr, int setfh)
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if(p > e)
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return -1;
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if(*nexthdr == FH){
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if(setfh || p+IP6FHDR > e || *p == FH)
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if(p+IP6FHDR > e || *p == FH)
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return -1;
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*q = *p;
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if(popfh)
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*q = *p;
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} else if(setfh)
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*q = FH;
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return p - bp->rp;
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@ -464,7 +468,7 @@ ip6reassemble(IP* ip, int uflen, Block* bp)
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*/
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for(f = ip->flisthead6; f != nil; f = fnext){
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fnext = f->next;
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if(ipcmp(f->src, src) == 0 && ipcmp(f->dst, dst) == 0 && f->id == id)
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if(f->id == id && ipcmp(f->src, src) == 0 && ipcmp(f->dst, dst) == 0)
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break;
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if(f->age < NOW){
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ip->stats[ReasmTimeout]++;
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@ -607,7 +611,6 @@ ip6reassemble(IP* ip, int uflen, Block* bp)
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if(len >= IP_MAX){
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ipfragfree6(ip, f);
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ip->stats[ReasmFails]++;
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qunlock(&ip->fraglock6);
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@ -79,6 +79,7 @@ enum {
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v6MINTU = 1280,
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HOP_LIMIT = 255,
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IP6HDR = 40, /* sizeof(Ip6hdr) = 8 + 2*16 */
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IP6FHDR = 8, /* sizeof(Fraghdr6) */
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/* option types */
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