3 files changed, 11 insertions(+), 7 deletions(-)

M ip/icmp.c
M ip/ip.c
M ip/ip.h

@@ 216,7 216,7 @@ icmpttlexceeded(Fs *f, uchar *ia, Block *bp)
 }
 
 static void
-icmpunreachable(Fs *f, Block *bp, int code)
+icmpunreachable(Fs *f, Block *bp, int code, int seq)
 {
 	Block	*nbp;
 	Icmp	*p, *np;


@@ 247,7 247,7 @@ icmpunreachable(Fs *f, Block *bp, int code)
 	np->code = code;
 	np->proto = IP_ICMPPROTO;
 	hnputs(np->icmpid, 0);
-	hnputs(np->seq, 0);
+	hnputs(np->seq, seq);
 	memset(np->cksum, 0, sizeof(np->cksum));
 	hnputs(np->cksum, ptclcsum(nbp, ICMP_IPSIZE, blocklen(nbp) - ICMP_IPSIZE));
 	ipoput4(f, nbp, 0, MAXTTL, DFLTTOS);


@@ 256,13 256,13 @@ icmpunreachable(Fs *f, Block *bp, int code)
 extern void
 icmpnoconv(Fs *f, Block *bp)
 {
-	icmpunreachable(f, bp, 3);
+	icmpunreachable(f, bp, 3, 0);
 }
 
 extern void
-icmpcantfrag(Fs *f, Block *bp)
+icmpcantfrag(Fs *f, Block *bp, int mtu)
 {
-	icmpunreachable(f, bp, 4);
+	icmpunreachable(f, bp, 4, mtu);
 }
 
 static void

@@ 317,7 317,7 @@ 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);
+		icmpcantfrag(f, bp, medialen);
 		netlog(f, Logip, "%V: eh->frag[0] & (IP_DF>>8)\n", eh->dst);
 		goto raise;
 	}


@@ 528,6 528,10 @@ ipiput4(Fs *f, Ipifc *ifc, Block *bp)
 		h = (Ip4hdr*)(bp->rp);
 	}
 
+	/* don't let any frag info go up the stack */
+	h->frag[0] = 0;
+	h->frag[1] = 0;
+
 	proto = h->proto;
 	p = Fsrcvpcol(f, proto);
 	if(p != nil && p->rcv != nil) {

@@ 614,7 614,7 @@ extern long	ipgateread6(Fs *f, char *cp, ulong offset, int n);
 extern void	iprouting(Fs*, int);
 extern void	closeifcconv(Ifcconv*);
 extern void	icmpnoconv(Fs*, Block*);
-extern void	icmpcantfrag(Fs*, Block*);
+extern void	icmpcantfrag(Fs*, Block*, int);
 extern void	icmpttlexceeded(Fs*, uchar*, Block*);
 extern ushort	ipcsum(uchar*);
 extern void	ipiput4(Fs*, Ipifc*, Block*);