Esempio n. 1
0
int ipv6_reassembly(struct sk_buff **skbp, int nhoff)
{
	struct sk_buff *skb = *skbp; 
	struct net_device *dev = skb->dev;
	struct frag_hdr *fhdr;
	struct frag_queue *fq;
	struct ipv6hdr *hdr;

	hdr = skb->nh.ipv6h;

	IP6_INC_STATS_BH(Ip6ReasmReqds);

	/* Jumbo payload inhibits frag. header */
	if (hdr->payload_len==0) {
		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
		return -1;
	}
	if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+sizeof(struct frag_hdr))) {
		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
		return -1;
	}

	hdr = skb->nh.ipv6h;
	fhdr = (struct frag_hdr *)skb->h.raw;

	if (!(fhdr->frag_off & __constant_htons(0xFFF9))) {
		/* It is not a fragmented frame */
		skb->h.raw += sizeof(struct frag_hdr);
		IP6_INC_STATS_BH(Ip6ReasmOKs);

		return (u8*)fhdr - skb->nh.raw;
	}

	if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh)
		ip6_evictor();

	if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr)) != NULL) {
		int ret = -1;

		spin_lock(&fq->lock);

		ip6_frag_queue(fq, skb, fhdr, nhoff);

		if (fq->last_in == (FIRST_IN|LAST_IN) &&
		    fq->meat == fq->len)
			ret = ip6_frag_reasm(fq, skbp, dev);

		spin_unlock(&fq->lock);
		fq_put(fq);
		return ret;
	}

	IP6_INC_STATS_BH(Ip6ReasmFails);
	kfree_skb(skb);
	return -1;
}
Esempio n. 2
0
static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
			   struct frag_hdr *fhdr, int nhoff)
{
	struct sk_buff *prev, *next;
	struct net_device *dev;
	int offset, end;
	struct net *net = dev_net(skb_dst(skb)->dev);

	if (fq->q.last_in & INET_FRAG_COMPLETE)
		goto err;

	offset = ntohs(fhdr->frag_off) & ~0x7;
	end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
			((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));

	if ((unsigned int)end > IPV6_MAXPLEN) {
		IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
				 IPSTATS_MIB_INHDRERRORS);
		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
				  ((u8 *)&fhdr->frag_off -
				   skb_network_header(skb)));
		return -1;
	}

	if (skb->ip_summed == CHECKSUM_COMPLETE) {
		const unsigned char *nh = skb_network_header(skb);
		skb->csum = csum_sub(skb->csum,
				     csum_partial(nh, (u8 *)(fhdr + 1) - nh,
						  0));
	}

	/* Is this the final fragment? */
	if (!(fhdr->frag_off & htons(IP6_MF))) {
		/* If we already have some bits beyond end
		 * or have different end, the segment is corrupted.
		 */
		if (end < fq->q.len ||
		    ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
			goto err;
		fq->q.last_in |= INET_FRAG_LAST_IN;
		fq->q.len = end;
	} else {
		/* Check if the fragment is rounded to 8 bytes.
		 * Required by the RFC.
		 */
		if (end & 0x7) {
			/* RFC2460 says always send parameter problem in
			 * this case. -DaveM
			 */
			IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
					 IPSTATS_MIB_INHDRERRORS);
			icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
					  offsetof(struct ipv6hdr, payload_len));
			return -1;
		}
		if (end > fq->q.len) {
			/* Some bits beyond end -> corruption. */
			if (fq->q.last_in & INET_FRAG_LAST_IN)
				goto err;
			fq->q.len = end;
		}
	}

	if (end == offset)
		goto err;

	/* Point into the IP datagram 'data' part. */
	if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
		goto err;

	if (pskb_trim_rcsum(skb, end - offset))
		goto err;

	/* Find out which fragments are in front and at the back of us
	 * in the chain of fragments so far.  We must know where to put
	 * this fragment, right?
	 */
	prev = fq->q.fragments_tail;
	if (!prev || FRAG6_CB(prev)->offset < offset) {
		next = NULL;
		goto found;
	}
	prev = NULL;
	for(next = fq->q.fragments; next != NULL; next = next->next) {
		if (FRAG6_CB(next)->offset >= offset)
			break;	/* bingo! */
		prev = next;
	}

found:
	/* RFC5722, Section 4:
	 *                                  When reassembling an IPv6 datagram, if
	 *   one or more its constituent fragments is determined to be an
	 *   overlapping fragment, the entire datagram (and any constituent
	 *   fragments, including those not yet received) MUST be silently
	 *   discarded.
	 */

	/* Check for overlap with preceding fragment. */
	if (prev &&
	    (FRAG6_CB(prev)->offset + prev->len) > offset)
		goto discard_fq;

	/* Look for overlap with succeeding segment. */
	if (next && FRAG6_CB(next)->offset < end)
		goto discard_fq;

	FRAG6_CB(skb)->offset = offset;

	/* Insert this fragment in the chain of fragments. */
	skb->next = next;
	if (!next)
		fq->q.fragments_tail = skb;
	if (prev)
		prev->next = skb;
	else
		fq->q.fragments = skb;

	dev = skb->dev;
	if (dev) {
		fq->iif = dev->ifindex;
		skb->dev = NULL;
	}
	fq->q.stamp = skb->tstamp;
	fq->q.meat += skb->len;
	atomic_add(skb->truesize, &fq->q.net->mem);

	/* The first fragment.
	 * nhoffset is obtained from the first fragment, of course.
	 */
	if (offset == 0) {
		fq->nhoffset = nhoff;
		fq->q.last_in |= INET_FRAG_FIRST_IN;
	}

	if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
	    fq->q.meat == fq->q.len)
		return ip6_frag_reasm(fq, prev, dev);

	write_lock(&ip6_frags.lock);
	list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);
	write_unlock(&ip6_frags.lock);
	return -1;

discard_fq:
	fq_kill(fq);
err:
	IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
		      IPSTATS_MIB_REASMFAILS);
	kfree_skb(skb);
	return -1;
}
Esempio n. 3
0
static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
			   struct frag_hdr *fhdr, int nhoff)
{
	struct sk_buff *prev, *next;
	struct net_device *dev;
	int offset, end;
	struct net *net = dev_net(skb_dst(skb)->dev);

	if (fq->q.last_in & INET_FRAG_COMPLETE)
		goto err;

	offset = ntohs(fhdr->frag_off) & ~0x7;
	end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
			((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));

	if ((unsigned int)end > IPV6_MAXPLEN) {
		IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
				 IPSTATS_MIB_INHDRERRORS);
		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
				  ((u8 *)&fhdr->frag_off -
				   skb_network_header(skb)));
		return -1;
	}

	if (skb->ip_summed == CHECKSUM_COMPLETE) {
		const unsigned char *nh = skb_network_header(skb);
		skb->csum = csum_sub(skb->csum,
				     csum_partial(nh, (u8 *)(fhdr + 1) - nh,
						  0));
	}

	
	if (!(fhdr->frag_off & htons(IP6_MF))) {
		if (end < fq->q.len ||
		    ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
			goto err;
		fq->q.last_in |= INET_FRAG_LAST_IN;
		fq->q.len = end;
	} else {
		if (end & 0x7) {
			IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
					 IPSTATS_MIB_INHDRERRORS);
			icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
					  offsetof(struct ipv6hdr, payload_len));
			return -1;
		}
		if (end > fq->q.len) {
			
			if (fq->q.last_in & INET_FRAG_LAST_IN)
				goto err;
			fq->q.len = end;
		}
	}

	if (end == offset)
		goto err;

	
	if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
		goto err;

	if (pskb_trim_rcsum(skb, end - offset))
		goto err;

	prev = fq->q.fragments_tail;
	if (!prev || FRAG6_CB(prev)->offset < offset) {
		next = NULL;
		goto found;
	}
	prev = NULL;
	for(next = fq->q.fragments; next != NULL; next = next->next) {
		if (FRAG6_CB(next)->offset >= offset)
			break;	
		prev = next;
	}

found:

	
	if (prev &&
	    (FRAG6_CB(prev)->offset + prev->len) > offset)
		goto discard_fq;

	
	if (next && FRAG6_CB(next)->offset < end)
		goto discard_fq;

	FRAG6_CB(skb)->offset = offset;

	
	skb->next = next;
	if (!next)
		fq->q.fragments_tail = skb;
	if (prev)
		prev->next = skb;
	else
		fq->q.fragments = skb;

	dev = skb->dev;
	if (dev) {
		fq->iif = dev->ifindex;
		skb->dev = NULL;
	}
	fq->q.stamp = skb->tstamp;
	fq->q.meat += skb->len;
	atomic_add(skb->truesize, &fq->q.net->mem);

	if (offset == 0) {
		fq->nhoffset = nhoff;
		fq->q.last_in |= INET_FRAG_FIRST_IN;
	}

	if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
	    fq->q.meat == fq->q.len) {
		int res;
		unsigned long orefdst = skb->_skb_refdst;

		skb->_skb_refdst = 0UL;
		res = ip6_frag_reasm(fq, prev, dev);
		skb->_skb_refdst = orefdst;
		return res;
	}

	skb_dst_drop(skb);

	write_lock(&ip6_frags.lock);
	list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);
	write_unlock(&ip6_frags.lock);
	return -1;

discard_fq:
	fq_kill(fq);
err:
	IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
		      IPSTATS_MIB_REASMFAILS);
	kfree_skb(skb);
	return -1;
}
Esempio n. 4
0
static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
			   struct frag_hdr *fhdr, int nhoff)
{
	struct sk_buff *prev, *next;
	struct net_device *dev;
	int offset, end;

	if (fq->q.last_in & INET_FRAG_COMPLETE)
		goto err;

	offset = ntohs(fhdr->frag_off) & ~0x7;
	end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
			((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));

	if ((unsigned int)end > IPV6_MAXPLEN) {
		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
				 IPSTATS_MIB_INHDRERRORS);
		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
				  ((u8 *)&fhdr->frag_off -
				   skb_network_header(skb)));
		return -1;
	}

	if (skb->ip_summed == CHECKSUM_COMPLETE) {
		const unsigned char *nh = skb_network_header(skb);
		skb->csum = csum_sub(skb->csum,
				     csum_partial(nh, (u8 *)(fhdr + 1) - nh,
						  0));
	}

	/* Is this the final fragment? */
	if (!(fhdr->frag_off & htons(IP6_MF))) {
		/* If we already have some bits beyond end
		 * or have different end, the segment is corrupted.
		 */
		if (end < fq->q.len ||
		    ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
			goto err;
		fq->q.last_in |= INET_FRAG_LAST_IN;
		fq->q.len = end;
	} else {
		/* Check if the fragment is rounded to 8 bytes.
		 * Required by the RFC.
		 */
		if (end & 0x7) {
			/* RFC2460 says always send parameter problem in
			 * this case. -DaveM
			 */
			IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
					 IPSTATS_MIB_INHDRERRORS);
			icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
					  offsetof(struct ipv6hdr, payload_len));
			return -1;
		}
		if (end > fq->q.len) {
			/* Some bits beyond end -> corruption. */
			if (fq->q.last_in & INET_FRAG_LAST_IN)
				goto err;
			fq->q.len = end;
		}
	}

	if (end == offset)
		goto err;

	/* Point into the IP datagram 'data' part. */
	if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
		goto err;

	if (pskb_trim_rcsum(skb, end - offset))
		goto err;

	/* Find out which fragments are in front and at the back of us
	 * in the chain of fragments so far.  We must know where to put
	 * this fragment, right?
	 */
	prev = NULL;
	for(next = fq->q.fragments; next != NULL; next = next->next) {
		if (FRAG6_CB(next)->offset >= offset)
			break;	/* bingo! */
		prev = next;
	}

	/* We found where to put this one.  Check for overlap with
	 * preceding fragment, and, if needed, align things so that
	 * any overlaps are eliminated.
	 */
	if (prev) {
		int i = (FRAG6_CB(prev)->offset + prev->len) - offset;

		if (i > 0) {
			offset += i;
			if (end <= offset)
				goto err;
			if (!pskb_pull(skb, i))
				goto err;
			if (skb->ip_summed != CHECKSUM_UNNECESSARY)
				skb->ip_summed = CHECKSUM_NONE;
		}
	}

	/* Look for overlap with succeeding segments.
	 * If we can merge fragments, do it.
	 */
	while (next && FRAG6_CB(next)->offset < end) {
		int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */

		if (i < next->len) {
			/* Eat head of the next overlapped fragment
			 * and leave the loop. The next ones cannot overlap.
			 */
			if (!pskb_pull(next, i))
				goto err;
			FRAG6_CB(next)->offset += i;	/* next fragment */
			fq->q.meat -= i;
			if (next->ip_summed != CHECKSUM_UNNECESSARY)
				next->ip_summed = CHECKSUM_NONE;
			break;
		} else {
			struct sk_buff *free_it = next;

			/* Old fragment is completely overridden with
			 * new one drop it.
			 */
			next = next->next;

			if (prev)
				prev->next = next;
			else
				fq->q.fragments = next;

			fq->q.meat -= free_it->len;
			frag_kfree_skb(fq->q.net, free_it, NULL);
		}
	}

	FRAG6_CB(skb)->offset = offset;

	/* Insert this fragment in the chain of fragments. */
	skb->next = next;
	if (prev)
		prev->next = skb;
	else
		fq->q.fragments = skb;

	dev = skb->dev;
	if (dev) {
		fq->iif = dev->ifindex;
		skb->dev = NULL;
	}
	fq->q.stamp = skb->tstamp;
	fq->q.meat += skb->len;
	atomic_add(skb->truesize, &fq->q.net->mem);

	/* The first fragment.
	 * nhoffset is obtained from the first fragment, of course.
	 */
	if (offset == 0) {
		fq->nhoffset = nhoff;
		fq->q.last_in |= INET_FRAG_FIRST_IN;
	}

	if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
	    fq->q.meat == fq->q.len)
		return ip6_frag_reasm(fq, prev, dev);

	write_lock(&ip6_frags.lock);
	list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);
	write_unlock(&ip6_frags.lock);
	return -1;

err:
	IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
	kfree_skb(skb);
	return -1;
}
Esempio n. 5
0
static struct frag_queue *
fq_find(struct net *net, __be32 id, const struct ipv6hdr *hdr, int iif)
{
	struct frag_v6_compare_key key = {
		.id = id,
		.saddr = hdr->saddr,
		.daddr = hdr->daddr,
		.user = IP6_DEFRAG_LOCAL_DELIVER,
		.iif = iif,
	};
	struct inet_frag_queue *q;

	if (!(ipv6_addr_type(&hdr->daddr) & (IPV6_ADDR_MULTICAST |
					    IPV6_ADDR_LINKLOCAL)))
		key.iif = 0;

	q = inet_frag_find(&net->ipv6.frags, &key);
	if (!q)
		return NULL;

	return container_of(q, struct frag_queue, q);
}

static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
			  struct frag_hdr *fhdr, int nhoff,
			  u32 *prob_offset)
{
	struct net *net = dev_net(skb_dst(skb)->dev);
	int offset, end, fragsize;
	struct sk_buff *prev_tail;
	struct net_device *dev;
	int err = -ENOENT;
	u8 ecn;

	if (fq->q.flags & INET_FRAG_COMPLETE)
		goto err;

	err = -EINVAL;
	offset = ntohs(fhdr->frag_off) & ~0x7;
	end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
			((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));

	if ((unsigned int)end > IPV6_MAXPLEN) {
		*prob_offset = (u8 *)&fhdr->frag_off - skb_network_header(skb);
		/* note that if prob_offset is set, the skb is freed elsewhere,
		 * we do not free it here.
		 */
		return -1;
	}

	ecn = ip6_frag_ecn(ipv6_hdr(skb));

	if (skb->ip_summed == CHECKSUM_COMPLETE) {
		const unsigned char *nh = skb_network_header(skb);
		skb->csum = csum_sub(skb->csum,
				     csum_partial(nh, (u8 *)(fhdr + 1) - nh,
						  0));
	}

	/* Is this the final fragment? */
	if (!(fhdr->frag_off & htons(IP6_MF))) {
		/* If we already have some bits beyond end
		 * or have different end, the segment is corrupted.
		 */
		if (end < fq->q.len ||
		    ((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len))
			goto discard_fq;
		fq->q.flags |= INET_FRAG_LAST_IN;
		fq->q.len = end;
	} else {
		/* Check if the fragment is rounded to 8 bytes.
		 * Required by the RFC.
		 */
		if (end & 0x7) {
			/* RFC2460 says always send parameter problem in
			 * this case. -DaveM
			 */
			*prob_offset = offsetof(struct ipv6hdr, payload_len);
			return -1;
		}
		if (end > fq->q.len) {
			/* Some bits beyond end -> corruption. */
			if (fq->q.flags & INET_FRAG_LAST_IN)
				goto discard_fq;
			fq->q.len = end;
		}
	}

	if (end == offset)
		goto discard_fq;

	err = -ENOMEM;
	/* Point into the IP datagram 'data' part. */
	if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
		goto discard_fq;

	err = pskb_trim_rcsum(skb, end - offset);
	if (err)
		goto discard_fq;

	/* Note : skb->rbnode and skb->dev share the same location. */
	dev = skb->dev;
	/* Makes sure compiler wont do silly aliasing games */
	barrier();

	prev_tail = fq->q.fragments_tail;
	err = inet_frag_queue_insert(&fq->q, skb, offset, end);
	if (err)
		goto insert_error;

	if (dev)
		fq->iif = dev->ifindex;

	fq->q.stamp = skb->tstamp;
	fq->q.meat += skb->len;
	fq->ecn |= ecn;
	add_frag_mem_limit(fq->q.net, skb->truesize);

	fragsize = -skb_network_offset(skb) + skb->len;
	if (fragsize > fq->q.max_size)
		fq->q.max_size = fragsize;

	/* The first fragment.
	 * nhoffset is obtained from the first fragment, of course.
	 */
	if (offset == 0) {
		fq->nhoffset = nhoff;
		fq->q.flags |= INET_FRAG_FIRST_IN;
	}

	if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
	    fq->q.meat == fq->q.len) {
		unsigned long orefdst = skb->_skb_refdst;

		skb->_skb_refdst = 0UL;
		err = ip6_frag_reasm(fq, skb, prev_tail, dev);
		skb->_skb_refdst = orefdst;
		return err;
	}

	skb_dst_drop(skb);
	return -EINPROGRESS;

insert_error:
	if (err == IPFRAG_DUP) {
		kfree_skb(skb);
		return -EINVAL;
	}
	err = -EINVAL;
	__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
			IPSTATS_MIB_REASM_OVERLAPS);
discard_fq:
	inet_frag_kill(&fq->q);
	__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
			IPSTATS_MIB_REASMFAILS);
err:
	kfree_skb(skb);
	return err;
}