Exemplo n.º 1
0
static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
			 struct net_device *dev)
{
	struct net *net = container_of(qp->q.net, struct net, ipv4.frags);
	struct iphdr *iph;
	struct sk_buff *fp, *head = qp->q.fragments;
	int len;
	int ihlen;
	int err;
	int sum_truesize;
	u8 ecn;

	ipq_kill(qp);

	ecn = ip_frag_ecn_table[qp->ecn];
	if (unlikely(ecn == 0xff)) {
		err = -EINVAL;
		goto out_fail;
	}
	/* Make the one we just received the head. */
	if (prev) {
		head = prev->next;
		fp = skb_clone(head, GFP_ATOMIC);
		if (!fp)
			goto out_nomem;

		fp->next = head->next;
		if (!fp->next)
			qp->q.fragments_tail = fp;
		prev->next = fp;

		skb_morph(head, qp->q.fragments);
		head->next = qp->q.fragments->next;

		consume_skb(qp->q.fragments);
		qp->q.fragments = head;
	}

	WARN_ON(head == NULL);
	WARN_ON(FRAG_CB(head)->offset != 0);

	/* Allocate a new buffer for the datagram. */
	ihlen = ip_hdrlen(head);
	len = ihlen + qp->q.len;

	err = -E2BIG;
	if (len > 65535)
		goto out_oversize;

	/* Head of list must not be cloned. */
	if (skb_unclone(head, GFP_ATOMIC))
		goto out_nomem;

	/* If the first fragment is fragmented itself, we split
	 * it to two chunks: the first with data and paged part
	 * and the second, holding only fragments. */
	if (skb_has_frag_list(head)) {
		struct sk_buff *clone;
		int i, plen = 0;

		if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
			goto out_nomem;
		clone->next = head->next;
		head->next = clone;
		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
		skb_frag_list_init(head);
		for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
			plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
		clone->len = clone->data_len = head->data_len - plen;
		head->data_len -= clone->len;
		head->len -= clone->len;
		clone->csum = 0;
		clone->ip_summed = head->ip_summed;
		add_frag_mem_limit(&qp->q, clone->truesize);
	}

	skb_push(head, head->data - skb_network_header(head));

	sum_truesize = head->truesize;
	for (fp = head->next; fp;) {
		bool headstolen;
		int delta;
		struct sk_buff *next = fp->next;

		sum_truesize += fp->truesize;
		if (head->ip_summed != fp->ip_summed)
			head->ip_summed = CHECKSUM_NONE;
		else if (head->ip_summed == CHECKSUM_COMPLETE)
			head->csum = csum_add(head->csum, fp->csum);

		if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
			kfree_skb_partial(fp, headstolen);
		} else {
			if (!skb_shinfo(head)->frag_list)
				skb_shinfo(head)->frag_list = fp;
			head->data_len += fp->len;
			head->len += fp->len;
			head->truesize += fp->truesize;
		}
		fp = next;
	}
	sub_frag_mem_limit(&qp->q, sum_truesize);

	head->next = NULL;
	head->dev = dev;
	head->tstamp = qp->q.stamp;
	IPCB(head)->frag_max_size = qp->q.max_size;

	iph = ip_hdr(head);
	/* max_size != 0 implies at least one fragment had IP_DF set */
	iph->frag_off = qp->q.max_size ? htons(IP_DF) : 0;
	iph->tot_len = htons(len);
	iph->tos |= ecn;

	ip_send_check(iph);

	IP_INC_STATS_BH(net, IPSTATS_MIB_REASMOKS);
	qp->q.fragments = NULL;
	qp->q.fragments_tail = NULL;
	return 0;

out_nomem:
	LIMIT_NETDEBUG(KERN_ERR pr_fmt("queue_glue: no memory for gluing queue %p\n"),
		       qp);
	err = -ENOMEM;
	goto out_fail;
out_oversize:
	net_info_ratelimited("Oversized IP packet from %pI4\n", &qp->saddr);
out_fail:
	IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS);
	return err;
}
Exemplo n.º 2
0
static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
			 struct net_device *dev)
{
	struct net *net = container_of(qp->q.net, struct net, ipv4.frags);
	struct iphdr *iph;
	struct sk_buff *fp, *head = qp->q.fragments;
	int len;
	int ihlen;
	int err;
	u8 ecn;

	ipq_kill(qp);

	ecn = ip_frag_ecn_table[qp->ecn];
	if (unlikely(ecn == 0xff)) {
		err = -EINVAL;
		goto out_fail;
	}
	/* Make the one we just received the head. */
	if (prev) {
		head = prev->next;
		fp = skb_clone(head, GFP_ATOMIC);
		if (!fp)
			goto out_nomem;

		fp->next = head->next;
		if (!fp->next)
			qp->q.fragments_tail = fp;
		prev->next = fp;

		skb_morph(head, qp->q.fragments);
		head->next = qp->q.fragments->next;

		consume_skb(qp->q.fragments);
		qp->q.fragments = head;
	}

	WARN_ON(!head);
	WARN_ON(FRAG_CB(head)->offset != 0);

	/* Allocate a new buffer for the datagram. */
	ihlen = ip_hdrlen(head);
	len = ihlen + qp->q.len;

	err = -E2BIG;
	if (len > 65535)
		goto out_oversize;

	/* Head of list must not be cloned. */
	if (skb_unclone(head, GFP_ATOMIC))
		goto out_nomem;

	/* If the first fragment is fragmented itself, we split
	 * it to two chunks: the first with data and paged part
	 * and the second, holding only fragments. */
	if (skb_has_frag_list(head)) {
		struct sk_buff *clone;
		int i, plen = 0;

		clone = alloc_skb(0, GFP_ATOMIC);
		if (!clone)
			goto out_nomem;
		clone->next = head->next;
		head->next = clone;
		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
		skb_frag_list_init(head);
		for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
			plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
		clone->len = clone->data_len = head->data_len - plen;
		head->data_len -= clone->len;
		head->len -= clone->len;
		clone->csum = 0;
		clone->ip_summed = head->ip_summed;
		add_frag_mem_limit(qp->q.net, clone->truesize);
	}

	skb_shinfo(head)->frag_list = head->next;
	skb_push(head, head->data - skb_network_header(head));

	for (fp=head->next; fp; fp = fp->next) {
		head->data_len += fp->len;
		head->len += fp->len;
		if (head->ip_summed != fp->ip_summed)
			head->ip_summed = CHECKSUM_NONE;
		else if (head->ip_summed == CHECKSUM_COMPLETE)
			head->csum = csum_add(head->csum, fp->csum);
		head->truesize += fp->truesize;
	}
	sub_frag_mem_limit(qp->q.net, head->truesize);

	head->next = NULL;
	head->dev = dev;
	head->tstamp = qp->q.stamp;
	IPCB(head)->frag_max_size = max(qp->max_df_size, qp->q.max_size);

	iph = ip_hdr(head);
	iph->tot_len = htons(len);
	iph->tos |= ecn;

	/* When we set IP_DF on a refragmented skb we must also force a
	 * call to ip_fragment to avoid forwarding a DF-skb of size s while
	 * original sender only sent fragments of size f (where f < s).
	 *
	 * We only set DF/IPSKB_FRAG_PMTU if such DF fragment was the largest
	 * frag seen to avoid sending tiny DF-fragments in case skb was built
	 * from one very small df-fragment and one large non-df frag.
	 */
	if (qp->max_df_size == qp->q.max_size) {
		IPCB(head)->flags |= IPSKB_FRAG_PMTU;
		iph->frag_off = htons(IP_DF);
	} else {
		iph->frag_off = 0;
	}

	ip_send_check(iph);

	IP_INC_STATS_BH(net, IPSTATS_MIB_REASMOKS);
	qp->q.fragments = NULL;
	qp->q.fragments_tail = NULL;
	return 0;

out_nomem:
	net_dbg_ratelimited("queue_glue: no memory for gluing queue %p\n", qp);
	err = -ENOMEM;
	goto out_fail;
out_oversize:
	net_info_ratelimited("Oversized IP packet from %pI4\n", &qp->saddr);
out_fail:
	IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS);
	return err;
}
Exemplo n.º 3
0
/* Add new segment to existing queue. */
static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
{
	struct sk_buff *prev, *next;
	struct net_device *dev;
	int flags, offset;
	int ihl, end;
	int err = -ENOENT;
	u8 ecn;

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

	if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) &&
	    unlikely(ip_frag_too_far(qp)) &&
	    unlikely(err = ip_frag_reinit(qp))) {
		ipq_kill(qp);
		goto err;
	}

	ecn = ip4_frag_ecn(ip_hdr(skb)->tos);
	offset = ntohs(ip_hdr(skb)->frag_off);
	flags = offset & ~IP_OFFSET;
	offset &= IP_OFFSET;
	offset <<= 3;		/* offset is in 8-byte chunks */
	ihl = ip_hdrlen(skb);

	/* Determine the position of this fragment. */
	end = offset + skb->len - skb_network_offset(skb) - ihl;
	err = -EINVAL;

	/* Is this the final fragment? */
	if ((flags & IP_MF) == 0) {
		/* If we already have some bits beyond end
		 * or have different end, the segment is corrupted.
		 */
		if (end < qp->q.len ||
		    ((qp->q.last_in & INET_FRAG_LAST_IN) && end != qp->q.len))
			goto err;
		qp->q.last_in |= INET_FRAG_LAST_IN;
		qp->q.len = end;
	} else {
		if (end&7) {
			end &= ~7;
			if (skb->ip_summed != CHECKSUM_UNNECESSARY)
				skb->ip_summed = CHECKSUM_NONE;
		}
		if (end > qp->q.len) {
			/* Some bits beyond end -> corruption. */
			if (qp->q.last_in & INET_FRAG_LAST_IN)
				goto err;
			qp->q.len = end;
		}
	}
	if (end == offset)
		goto err;

	err = -ENOMEM;
	if (!pskb_pull(skb, skb_network_offset(skb) + ihl))
		goto err;

	err = pskb_trim_rcsum(skb, end - offset);
	if (err)
		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 = qp->q.fragments_tail;
	if (!prev || FRAG_CB(prev)->offset < offset) {
		next = NULL;
		goto found;
	}
	prev = NULL;
	for (next = qp->q.fragments; next != NULL; next = next->next) {
		if (FRAG_CB(next)->offset >= offset)
			break;	/* bingo! */
		prev = next;
	}

found:
	/* 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 = (FRAG_CB(prev)->offset + prev->len) - offset;

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

	err = -ENOMEM;

	while (next && FRAG_CB(next)->offset < end) {
		int i = end - FRAG_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;
			FRAG_CB(next)->offset += i;
			qp->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
				qp->q.fragments = next;

			qp->q.meat -= free_it->len;
			sub_frag_mem_limit(&qp->q, free_it->truesize);
			kfree_skb(free_it);
		}
	}

	FRAG_CB(skb)->offset = offset;

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

	dev = skb->dev;
	if (dev) {
		qp->iif = dev->ifindex;
		skb->dev = NULL;
	}
	qp->q.stamp = skb->tstamp;
	qp->q.meat += skb->len;
	qp->ecn |= ecn;
	add_frag_mem_limit(&qp->q, skb->truesize);
	if (offset == 0)
		qp->q.last_in |= INET_FRAG_FIRST_IN;

	if (ip_hdr(skb)->frag_off & htons(IP_DF) &&
	    skb->len + ihl > qp->q.max_size)
		qp->q.max_size = skb->len + ihl;

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

		skb->_skb_refdst = 0UL;
		err = ip_frag_reasm(qp, prev, dev);
		skb->_skb_refdst = orefdst;
		return err;
	}

	skb_dst_drop(skb);
	inet_frag_lru_move(&qp->q);
	return -EINPROGRESS;

err:
	kfree_skb(skb);
	return err;
}
Exemplo n.º 4
0
static int lowpan_frag_queue(struct lowpan_frag_queue *fq,
			     struct sk_buff *skb, const u8 frag_type)
{
	struct sk_buff *prev, *next;
	struct net_device *dev;
	int end, offset;

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

	offset = lowpan_cb(skb)->d_offset << 3;
	end = lowpan_cb(skb)->d_size;

	/* Is this the final fragment? */
	if (offset + skb->len == end) {
		/* 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 err;
		fq->q.flags |= INET_FRAG_LAST_IN;
		fq->q.len = end;
	} else {
		if (end > fq->q.len) {
			/* Some bits beyond end -> corruption. */
			if (fq->q.flags & INET_FRAG_LAST_IN)
				goto err;
			fq->q.len = end;
		}
	}

	/* 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 || lowpan_cb(prev)->d_offset < lowpan_cb(skb)->d_offset) {
		next = NULL;
		goto found;
	}
	prev = NULL;
	for (next = fq->q.fragments; next != NULL; next = next->next) {
		if (lowpan_cb(next)->d_offset >= lowpan_cb(skb)->d_offset)
			break;	/* bingo! */
		prev = next;
	}

found:
	/* 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)
		skb->dev = NULL;

	fq->q.stamp = skb->tstamp;
	if (frag_type == LOWPAN_DISPATCH_FRAG1) {
		/* Calculate uncomp. 6lowpan header to estimate full size */
		fq->q.meat += lowpan_uncompress_size(skb, NULL);
		fq->q.flags |= INET_FRAG_FIRST_IN;
	} else {
		fq->q.meat += skb->len;
	}
	add_frag_mem_limit(&fq->q, skb->truesize);

	if (fq->q.flags == (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 = lowpan_frag_reasm(fq, prev, dev);
		skb->_skb_refdst = orefdst;
		return res;
	}

	return -1;
err:
	kfree_skb(skb);
	return -1;
}
Exemplo n.º 5
0
/*	Check if this packet is complete.
 *	Returns NULL on failure by any reason, and pointer
 *	to current nexthdr field in reassembled frame.
 *
 *	It is called with locked fq, and caller must check that
 *	queue is eligible for reassembly i.e. it is not COMPLETE,
 *	the last and the first frames arrived and all the bits are here.
 */
static int lowpan_frag_reasm(struct lowpan_frag_queue *fq, struct sk_buff *prev,
			     struct net_device *dev)
{
	struct sk_buff *fp, *head = fq->q.fragments;
	int sum_truesize;

	inet_frag_kill(&fq->q, &lowpan_frags);

	/* Make the one we just received the head. */
	if (prev) {
		head = prev->next;
		fp = skb_clone(head, GFP_ATOMIC);

		if (!fp)
			goto out_oom;

		fp->next = head->next;
		if (!fp->next)
			fq->q.fragments_tail = fp;
		prev->next = fp;

		skb_morph(head, fq->q.fragments);
		head->next = fq->q.fragments->next;

		consume_skb(fq->q.fragments);
		fq->q.fragments = head;
	}

	/* Head of list must not be cloned. */
	if (skb_unclone(head, GFP_ATOMIC))
		goto out_oom;

	/* If the first fragment is fragmented itself, we split
	 * it to two chunks: the first with data and paged part
	 * and the second, holding only fragments.
	 */
	if (skb_has_frag_list(head)) {
		struct sk_buff *clone;
		int i, plen = 0;

		clone = alloc_skb(0, GFP_ATOMIC);
		if (!clone)
			goto out_oom;
		clone->next = head->next;
		head->next = clone;
		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
		skb_frag_list_init(head);
		for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
			plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
		clone->len = head->data_len - plen;
		clone->data_len = clone->len;
		head->data_len -= clone->len;
		head->len -= clone->len;
		add_frag_mem_limit(&fq->q, clone->truesize);
	}

	WARN_ON(head == NULL);

	sum_truesize = head->truesize;
	for (fp = head->next; fp;) {
		bool headstolen;
		int delta;
		struct sk_buff *next = fp->next;

		sum_truesize += fp->truesize;
		if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
			kfree_skb_partial(fp, headstolen);
		} else {
			if (!skb_shinfo(head)->frag_list)
				skb_shinfo(head)->frag_list = fp;
			head->data_len += fp->len;
			head->len += fp->len;
			head->truesize += fp->truesize;
		}
		fp = next;
	}
	sub_frag_mem_limit(&fq->q, sum_truesize);

	head->next = NULL;
	head->dev = dev;
	head->tstamp = fq->q.stamp;

	fq->q.fragments = NULL;
	fq->q.fragments_tail = NULL;

	return 1;
out_oom:
	net_dbg_ratelimited("lowpan_frag_reasm: no memory for reassembly\n");
	return -1;
}
Exemplo n.º 6
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;
}
Exemplo n.º 7
0
/*
 *	Check if this packet is complete.
 *	Returns NULL on failure by any reason, and pointer
 *	to current nexthdr field in reassembled frame.
 *
 *	It is called with locked fq, and caller must check that
 *	queue is eligible for reassembly i.e. it is not COMPLETE,
 *	the last and the first frames arrived and all the bits are here.
 */
static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
			  struct net_device *dev)
{
	struct net *net = container_of(fq->q.net, struct net, ipv6.frags);
	struct sk_buff *fp, *head = fq->q.fragments;
	int    payload_len;
	unsigned int nhoff;
	int sum_truesize;
	u8 ecn;

	inet_frag_kill(&fq->q, &ip6_frags);

	ecn = ip_frag_ecn_table[fq->ecn];
	if (unlikely(ecn == 0xff))
		goto out_fail;

	/* Make the one we just received the head. */
	if (prev) {
		head = prev->next;
		fp = skb_clone(head, GFP_ATOMIC);

		if (!fp)
			goto out_oom;

		fp->next = head->next;
		if (!fp->next)
			fq->q.fragments_tail = fp;
		prev->next = fp;

		skb_morph(head, fq->q.fragments);
		head->next = fq->q.fragments->next;

		consume_skb(fq->q.fragments);
		fq->q.fragments = head;
	}

	WARN_ON(head == NULL);
	WARN_ON(FRAG6_CB(head)->offset != 0);

	/* Unfragmented part is taken from the first segment. */
	payload_len = ((head->data - skb_network_header(head)) -
		       sizeof(struct ipv6hdr) + fq->q.len -
		       sizeof(struct frag_hdr));
	if (payload_len > IPV6_MAXPLEN)
		goto out_oversize;

	/* Head of list must not be cloned. */
	if (skb_unclone(head, GFP_ATOMIC))
		goto out_oom;

	/* If the first fragment is fragmented itself, we split
	 * it to two chunks: the first with data and paged part
	 * and the second, holding only fragments. */
	if (skb_has_frag_list(head)) {
		struct sk_buff *clone;
		int i, plen = 0;

		clone = alloc_skb(0, GFP_ATOMIC);
		if (!clone)
			goto out_oom;
		clone->next = head->next;
		head->next = clone;
		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
		skb_frag_list_init(head);
		for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
			plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
		clone->len = clone->data_len = head->data_len - plen;
		head->data_len -= clone->len;
		head->len -= clone->len;
		clone->csum = 0;
		clone->ip_summed = head->ip_summed;
		add_frag_mem_limit(fq->q.net, clone->truesize);
	}

	/* We have to remove fragment header from datagram and to relocate
	 * header in order to calculate ICV correctly. */
	nhoff = fq->nhoffset;
	skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
	memmove(head->head + sizeof(struct frag_hdr), head->head,
		(head->data - head->head) - sizeof(struct frag_hdr));
	if (skb_mac_header_was_set(head))
		head->mac_header += sizeof(struct frag_hdr);
	head->network_header += sizeof(struct frag_hdr);

	skb_reset_transport_header(head);
	skb_push(head, head->data - skb_network_header(head));

	sum_truesize = head->truesize;
	for (fp = head->next; fp;) {
		bool headstolen;
		int delta;
		struct sk_buff *next = fp->next;

		sum_truesize += fp->truesize;
		if (head->ip_summed != fp->ip_summed)
			head->ip_summed = CHECKSUM_NONE;
		else if (head->ip_summed == CHECKSUM_COMPLETE)
			head->csum = csum_add(head->csum, fp->csum);

		if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
			kfree_skb_partial(fp, headstolen);
		} else {
			if (!skb_shinfo(head)->frag_list)
				skb_shinfo(head)->frag_list = fp;
			head->data_len += fp->len;
			head->len += fp->len;
			head->truesize += fp->truesize;
		}
		fp = next;
	}
	sub_frag_mem_limit(fq->q.net, sum_truesize);

	head->next = NULL;
	head->dev = dev;
	head->tstamp = fq->q.stamp;
	ipv6_hdr(head)->payload_len = htons(payload_len);
	ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn);
	IP6CB(head)->nhoff = nhoff;
	IP6CB(head)->flags |= IP6SKB_FRAGMENTED;
	IP6CB(head)->frag_max_size = fq->q.max_size;

	/* Yes, and fold redundant checksum back. 8) */
	skb_postpush_rcsum(head, skb_network_header(head),
			   skb_network_header_len(head));

	rcu_read_lock();
	__IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
	rcu_read_unlock();
	fq->q.fragments = NULL;
	fq->q.fragments_tail = NULL;
	return 1;

out_oversize:
	net_dbg_ratelimited("ip6_frag_reasm: payload len = %d\n", payload_len);
	goto out_fail;
out_oom:
	net_dbg_ratelimited("ip6_frag_reasm: no memory for reassembly\n");
out_fail:
	rcu_read_lock();
	__IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
	rcu_read_unlock();
	return -1;
}
Exemplo n.º 8
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, fragsize;
	struct net *net = dev_net(skb_dst(skb)->dev);
	u8 ecn;

	if (fq->q.flags & 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(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;
	}

	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 err;
		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
			 */
			__IP6_INC_STATS(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.flags & 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, amended by Errata ID : 3089
	 *                          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) 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;
	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) {
		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);
	return -1;

discard_fq:
	inet_frag_kill(&fq->q, &ip6_frags);
err:
	__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
			IPSTATS_MIB_REASMFAILS);
	kfree_skb(skb);
	return -1;
}
Exemplo n.º 9
0
/* Build a new IP datagram from all its fragments. */
static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb,
			 struct sk_buff *prev_tail, struct net_device *dev)
{
	struct net *net = container_of(qp->q.net, struct net, ipv4.frags);
	struct iphdr *iph;
	struct sk_buff *fp, *head = skb_rb_first(&qp->q.rb_fragments);
	struct sk_buff **nextp; /* To build frag_list. */
	struct rb_node *rbn;
	int len;
	int ihlen;
	int err;
	u8 ecn;

	ipq_kill(qp);

	ecn = ip_frag_ecn_table[qp->ecn];
	if (unlikely(ecn == 0xff)) {
		err = -EINVAL;
		goto out_fail;
	}
	/* Make the one we just received the head. */
	if (head != skb) {
		fp = skb_clone(skb, GFP_ATOMIC);
		if (!fp)
			goto out_nomem;
		FRAG_CB(fp)->next_frag = FRAG_CB(skb)->next_frag;
		if (RB_EMPTY_NODE(&skb->rbnode))
			FRAG_CB(prev_tail)->next_frag = fp;
		else
			rb_replace_node(&skb->rbnode, &fp->rbnode,
					&qp->q.rb_fragments);
		if (qp->q.fragments_tail == skb)
			qp->q.fragments_tail = fp;
		skb_morph(skb, head);
		FRAG_CB(skb)->next_frag = FRAG_CB(head)->next_frag;
		rb_replace_node(&head->rbnode, &skb->rbnode,
				&qp->q.rb_fragments);
		consume_skb(head);
		head = skb;
	}

	WARN_ON(head->ip_defrag_offset != 0);

	/* Allocate a new buffer for the datagram. */
	ihlen = ip_hdrlen(head);
	len = ihlen + qp->q.len;

	err = -E2BIG;
	if (len > 65535)
		goto out_oversize;

	/* Head of list must not be cloned. */
	if (skb_unclone(head, GFP_ATOMIC))
		goto out_nomem;

	/* If the first fragment is fragmented itself, we split
	 * it to two chunks: the first with data and paged part
	 * and the second, holding only fragments. */
	if (skb_has_frag_list(head)) {
		struct sk_buff *clone;
		int i, plen = 0;

		clone = alloc_skb(0, GFP_ATOMIC);
		if (!clone)
			goto out_nomem;
		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
		skb_frag_list_init(head);
		for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
			plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
		clone->len = clone->data_len = head->data_len - plen;
		head->truesize += clone->truesize;
		clone->csum = 0;
		clone->ip_summed = head->ip_summed;
		add_frag_mem_limit(qp->q.net, clone->truesize);
		skb_shinfo(head)->frag_list = clone;
		nextp = &clone->next;
	} else {
		nextp = &skb_shinfo(head)->frag_list;
	}

	skb_push(head, head->data - skb_network_header(head));

	/* Traverse the tree in order, to build frag_list. */
	fp = FRAG_CB(head)->next_frag;
	rbn = rb_next(&head->rbnode);
	rb_erase(&head->rbnode, &qp->q.rb_fragments);
	while (rbn || fp) {
		/* fp points to the next sk_buff in the current run;
		 * rbn points to the next run.
		 */
		/* Go through the current run. */
		while (fp) {
			*nextp = fp;
			nextp = &fp->next;
			fp->prev = NULL;
			memset(&fp->rbnode, 0, sizeof(fp->rbnode));
			head->data_len += fp->len;
			head->len += fp->len;
			if (head->ip_summed != fp->ip_summed)
				head->ip_summed = CHECKSUM_NONE;
			else if (head->ip_summed == CHECKSUM_COMPLETE)
				head->csum = csum_add(head->csum, fp->csum);
			head->truesize += fp->truesize;
			fp = FRAG_CB(fp)->next_frag;
		}
		/* Move to the next run. */
		if (rbn) {
			struct rb_node *rbnext = rb_next(rbn);

			fp = rb_to_skb(rbn);
			rb_erase(rbn, &qp->q.rb_fragments);
			rbn = rbnext;
		}
	}
	sub_frag_mem_limit(qp->q.net, head->truesize);

	*nextp = NULL;
	head->next = NULL;
	head->prev = NULL;
	head->dev = dev;
	head->tstamp = qp->q.stamp;
	IPCB(head)->frag_max_size = max(qp->max_df_size, qp->q.max_size);

	iph = ip_hdr(head);
	iph->tot_len = htons(len);
	iph->tos |= ecn;

	/* When we set IP_DF on a refragmented skb we must also force a
	 * call to ip_fragment to avoid forwarding a DF-skb of size s while
	 * original sender only sent fragments of size f (where f < s).
	 *
	 * We only set DF/IPSKB_FRAG_PMTU if such DF fragment was the largest
	 * frag seen to avoid sending tiny DF-fragments in case skb was built
	 * from one very small df-fragment and one large non-df frag.
	 */
	if (qp->max_df_size == qp->q.max_size) {
		IPCB(head)->flags |= IPSKB_FRAG_PMTU;
		iph->frag_off = htons(IP_DF);
	} else {
		iph->frag_off = 0;
	}

	ip_send_check(iph);

	__IP_INC_STATS(net, IPSTATS_MIB_REASMOKS);
	qp->q.fragments = NULL;
	qp->q.rb_fragments = RB_ROOT;
	qp->q.fragments_tail = NULL;
	qp->q.last_run_head = NULL;
	return 0;

out_nomem:
	net_dbg_ratelimited("queue_glue: no memory for gluing queue %p\n", qp);
	err = -ENOMEM;
	goto out_fail;
out_oversize:
	net_info_ratelimited("Oversized IP packet from %pI4\n", &qp->q.key.v4.saddr);
out_fail:
	__IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
	return err;
}
Exemplo n.º 10
0
/* Add new segment to existing queue. */
static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
{
	struct net *net = container_of(qp->q.net, struct net, ipv4.frags);
	struct rb_node **rbn, *parent;
	struct sk_buff *skb1, *prev_tail;
	struct net_device *dev;
	unsigned int fragsize;
	int flags, offset;
	int ihl, end;
	int err = -ENOENT;
	u8 ecn;

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

	if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) &&
	    unlikely(ip_frag_too_far(qp)) &&
	    unlikely(err = ip_frag_reinit(qp))) {
		ipq_kill(qp);
		goto err;
	}

	ecn = ip4_frag_ecn(ip_hdr(skb)->tos);
	offset = ntohs(ip_hdr(skb)->frag_off);
	flags = offset & ~IP_OFFSET;
	offset &= IP_OFFSET;
	offset <<= 3;		/* offset is in 8-byte chunks */
	ihl = ip_hdrlen(skb);

	/* Determine the position of this fragment. */
	end = offset + skb->len - skb_network_offset(skb) - ihl;
	err = -EINVAL;

	/* Is this the final fragment? */
	if ((flags & IP_MF) == 0) {
		/* If we already have some bits beyond end
		 * or have different end, the segment is corrupted.
		 */
		if (end < qp->q.len ||
		    ((qp->q.flags & INET_FRAG_LAST_IN) && end != qp->q.len))
			goto err;
		qp->q.flags |= INET_FRAG_LAST_IN;
		qp->q.len = end;
	} else {
		if (end&7) {
			end &= ~7;
			if (skb->ip_summed != CHECKSUM_UNNECESSARY)
				skb->ip_summed = CHECKSUM_NONE;
		}
		if (end > qp->q.len) {
			/* Some bits beyond end -> corruption. */
			if (qp->q.flags & INET_FRAG_LAST_IN)
				goto err;
			qp->q.len = end;
		}
	}
	if (end == offset)
		goto err;

	err = -ENOMEM;
	if (!pskb_pull(skb, skb_network_offset(skb) + ihl))
		goto err;

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

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

	/* RFC5722, Section 4, amended by Errata ID : 3089
	 *                          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) MUST be silently discarded.
	 *
	 * We do the same here for IPv4 (and increment an snmp counter).
	 */

	/* Find out where to put this fragment.  */
	prev_tail = qp->q.fragments_tail;
	if (!prev_tail)
		ip4_frag_create_run(&qp->q, skb);  /* First fragment. */
	else if (prev_tail->ip_defrag_offset + prev_tail->len < end) {
		/* This is the common case: skb goes to the end. */
		/* Detect and discard overlaps. */
		if (offset < prev_tail->ip_defrag_offset + prev_tail->len)
			goto discard_qp;
		if (offset == prev_tail->ip_defrag_offset + prev_tail->len)
			ip4_frag_append_to_last_run(&qp->q, skb);
		else
			ip4_frag_create_run(&qp->q, skb);
	} else {
		/* Binary search. Note that skb can become the first fragment,
		 * but not the last (covered above).
		 */
		rbn = &qp->q.rb_fragments.rb_node;
		do {
			parent = *rbn;
			skb1 = rb_to_skb(parent);
			if (end <= skb1->ip_defrag_offset)
				rbn = &parent->rb_left;
			else if (offset >= skb1->ip_defrag_offset +
						FRAG_CB(skb1)->frag_run_len)
				rbn = &parent->rb_right;
			else /* Found an overlap with skb1. */
				goto discard_qp;
		} while (*rbn);
		/* Here we have parent properly set, and rbn pointing to
		 * one of its NULL left/right children. Insert skb.
		 */
		ip4_frag_init_run(skb);
		rb_link_node(&skb->rbnode, parent, rbn);
		rb_insert_color(&skb->rbnode, &qp->q.rb_fragments);
	}

	if (dev)
		qp->iif = dev->ifindex;
	skb->ip_defrag_offset = offset;

	qp->q.stamp = skb->tstamp;
	qp->q.meat += skb->len;
	qp->ecn |= ecn;
	add_frag_mem_limit(qp->q.net, skb->truesize);
	if (offset == 0)
		qp->q.flags |= INET_FRAG_FIRST_IN;

	fragsize = skb->len + ihl;

	if (fragsize > qp->q.max_size)
		qp->q.max_size = fragsize;

	if (ip_hdr(skb)->frag_off & htons(IP_DF) &&
	    fragsize > qp->max_df_size)
		qp->max_df_size = fragsize;

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

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

	skb_dst_drop(skb);
	return -EINPROGRESS;

discard_qp:
	inet_frag_kill(&qp->q);
	err = -EINVAL;
	__IP_INC_STATS(net, IPSTATS_MIB_REASM_OVERLAPS);
err:
	kfree_skb(skb);
	return err;
}