Fixed MTP to work with TWRP

net/ipv4/ip_fragment.c

@@ -0,0 +1,870 @@
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the  BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		The IP fragmentation functionality.
+ *
+ * Authors:	Fred N. van Kempen <waltje@uWalt.NL.Mugnet.ORG>
+ *		Alan Cox <alan@lxorguk.ukuu.org.uk>
+ *
+ * Fixes:
+ *		Alan Cox	:	Split from ip.c , see ip_input.c for history.
+ *		David S. Miller :	Begin massive cleanup...
+ *		Andi Kleen	:	Add sysctls.
+ *		xxxx		:	Overlapfrag bug.
+ *		Ultima          :       ip_expire() kernel panic.
+ *		Bill Hawes	:	Frag accounting and evictor fixes.
+ *		John McDonald	:	0 length frag bug.
+ *		Alexey Kuznetsov:	SMP races, threading, cleanup.
+ *		Patrick McHardy :	LRU queue of frag heads for evictor.
+ */
+
+#define pr_fmt(fmt) "IPv4: " fmt
+
+#include <linux/compiler.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/jiffies.h>
+#include <linux/skbuff.h>
+#include <linux/list.h>
+#include <linux/ip.h>
+#include <linux/icmp.h>
+#include <linux/netdevice.h>
+#include <linux/jhash.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <net/route.h>
+#include <net/dst.h>
+#include <net/sock.h>
+#include <net/ip.h>
+#include <net/icmp.h>
+#include <net/checksum.h>
+#include <net/inetpeer.h>
+#include <net/inet_frag.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/inet.h>
+#include <linux/netfilter_ipv4.h>
+#include <net/inet_ecn.h>
+
+/* NOTE. Logic of IP defragmentation is parallel to corresponding IPv6
+ * code now. If you change something here, _PLEASE_ update ipv6/reassembly.c
+ * as well. Or notify me, at least. --ANK
+ */
+
+static int sysctl_ipfrag_max_dist __read_mostly = 64;
+static const char ip_frag_cache_name[] = "ip4-frags";
+
+struct ipfrag_skb_cb
+{
+	struct inet_skb_parm	h;
+	int			offset;
+};
+
+#define FRAG_CB(skb)	((struct ipfrag_skb_cb *)((skb)->cb))
+
+/* Describe an entry in the "incomplete datagrams" queue. */
+struct ipq {
+	struct inet_frag_queue q;
+
+	u32		user;
+	__be32		saddr;
+	__be32		daddr;
+	__be16		id;
+	u8		protocol;
+	u8		ecn; /* RFC3168 support */
+	int             iif;
+	unsigned int    rid;
+	struct inet_peer *peer;
+};
+
+static inline u8 ip4_frag_ecn(u8 tos)
+{
+	return 1 << (tos & INET_ECN_MASK);
+}
+
+static struct inet_frags ip4_frags;
+
+int ip_frag_mem(struct net *net)
+{
+	return sum_frag_mem_limit(&net->ipv4.frags);
+}
+
+static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
+			 struct net_device *dev);
+
+struct ip4_create_arg {
+	struct iphdr *iph;
+	u32 user;
+};
+
+static unsigned int ipqhashfn(__be16 id, __be32 saddr, __be32 daddr, u8 prot)
+{
+	net_get_random_once(&ip4_frags.rnd, sizeof(ip4_frags.rnd));
+	return jhash_3words((__force u32)id << 16 | prot,
+			    (__force u32)saddr, (__force u32)daddr,
+			    ip4_frags.rnd);
+}
+
+static unsigned int ip4_hashfn(const struct inet_frag_queue *q)
+{
+	const struct ipq *ipq;
+
+	ipq = container_of(q, struct ipq, q);
+	return ipqhashfn(ipq->id, ipq->saddr, ipq->daddr, ipq->protocol);
+}
+
+static bool ip4_frag_match(const struct inet_frag_queue *q, const void *a)
+{
+	const struct ipq *qp;
+	const struct ip4_create_arg *arg = a;
+
+	qp = container_of(q, struct ipq, q);
+	return	qp->id == arg->iph->id &&
+		qp->saddr == arg->iph->saddr &&
+		qp->daddr == arg->iph->daddr &&
+		qp->protocol == arg->iph->protocol &&
+		qp->user == arg->user;
+}
+
+static void ip4_frag_init(struct inet_frag_queue *q, const void *a)
+{
+	struct ipq *qp = container_of(q, struct ipq, q);
+	struct netns_ipv4 *ipv4 = container_of(q->net, struct netns_ipv4,
+					       frags);
+	struct net *net = container_of(ipv4, struct net, ipv4);
+
+	const struct ip4_create_arg *arg = a;
+
+	qp->protocol = arg->iph->protocol;
+	qp->id = arg->iph->id;
+	qp->ecn = ip4_frag_ecn(arg->iph->tos);
+	qp->saddr = arg->iph->saddr;
+	qp->daddr = arg->iph->daddr;
+	qp->user = arg->user;
+	qp->peer = sysctl_ipfrag_max_dist ?
+		inet_getpeer_v4(net->ipv4.peers, arg->iph->saddr, 1) : NULL;
+}
+
+static __inline__ void ip4_frag_free(struct inet_frag_queue *q)
+{
+	struct ipq *qp;
+
+	qp = container_of(q, struct ipq, q);
+	if (qp->peer)
+		inet_putpeer(qp->peer);
+}
+
+
+/* Destruction primitives. */
+
+static __inline__ void ipq_put(struct ipq *ipq)
+{
+	inet_frag_put(&ipq->q, &ip4_frags);
+}
+
+/* Kill ipq entry. It is not destroyed immediately,
+ * because caller (and someone more) holds reference count.
+ */
+static void ipq_kill(struct ipq *ipq)
+{
+	inet_frag_kill(&ipq->q, &ip4_frags);
+}
+
+/*
+ * Oops, a fragment queue timed out.  Kill it and send an ICMP reply.
+ */
+static void ip_expire(unsigned long arg)
+{
+	struct ipq *qp;
+	struct net *net;
+
+	qp = container_of((struct inet_frag_queue *) arg, struct ipq, q);
+	net = container_of(qp->q.net, struct net, ipv4.frags);
+
+	spin_lock(&qp->q.lock);
+
+	if (qp->q.flags & INET_FRAG_COMPLETE)
+		goto out;
+
+	ipq_kill(qp);
+	IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS);
+
+	if (!(qp->q.flags & INET_FRAG_EVICTED)) {
+		struct sk_buff *head = qp->q.fragments;
+		const struct iphdr *iph;
+		int err;
+
+		IP_INC_STATS_BH(net, IPSTATS_MIB_REASMTIMEOUT);
+
+		if (!(qp->q.flags & INET_FRAG_FIRST_IN) || !qp->q.fragments)
+			goto out;
+
+		rcu_read_lock();
+		head->dev = dev_get_by_index_rcu(net, qp->iif);
+		if (!head->dev)
+			goto out_rcu_unlock;
+
+		/* skb has no dst, perform route lookup again */
+		iph = ip_hdr(head);
+		err = ip_route_input_noref(head, iph->daddr, iph->saddr,
+					   iph->tos, head->dev);
+		if (err)
+			goto out_rcu_unlock;
+
+		/* Only an end host needs to send an ICMP
+		 * "Fragment Reassembly Timeout" message, per RFC792.
+		 */
+		if (qp->user == IP_DEFRAG_AF_PACKET ||
+		    ((qp->user >= IP_DEFRAG_CONNTRACK_IN) &&
+		     (qp->user <= __IP_DEFRAG_CONNTRACK_IN_END) &&
+		     (skb_rtable(head)->rt_type != RTN_LOCAL)))
+			goto out_rcu_unlock;
+
+		/* Send an ICMP "Fragment Reassembly Timeout" message. */
+		icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0);
+out_rcu_unlock:
+		rcu_read_unlock();
+	}
+out:
+	spin_unlock(&qp->q.lock);
+	ipq_put(qp);
+}
+
+/* Find the correct entry in the "incomplete datagrams" queue for
+ * this IP datagram, and create new one, if nothing is found.
+ */
+static inline struct ipq *ip_find(struct net *net, struct iphdr *iph, u32 user)
+{
+	struct inet_frag_queue *q;
+	struct ip4_create_arg arg;
+	unsigned int hash;
+
+	arg.iph = iph;
+	arg.user = user;
+
+	hash = ipqhashfn(iph->id, iph->saddr, iph->daddr, iph->protocol);
+
+	q = inet_frag_find(&net->ipv4.frags, &ip4_frags, &arg, hash);
+	if (IS_ERR_OR_NULL(q)) {
+		inet_frag_maybe_warn_overflow(q, pr_fmt());
+		return NULL;
+	}
+	return container_of(q, struct ipq, q);
+}
+
+/* Is the fragment too far ahead to be part of ipq? */
+static inline int ip_frag_too_far(struct ipq *qp)
+{
+	struct inet_peer *peer = qp->peer;
+	unsigned int max = sysctl_ipfrag_max_dist;
+	unsigned int start, end;
+
+	int rc;
+
+	if (!peer || !max)
+		return 0;
+
+	start = qp->rid;
+	end = atomic_inc_return(&peer->rid);
+	qp->rid = end;
+
+	rc = qp->q.fragments && (end - start) > max;
+
+	if (rc) {
+		struct net *net;
+
+		net = container_of(qp->q.net, struct net, ipv4.frags);
+		IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS);
+	}
+
+	return rc;
+}
+
+static int ip_frag_reinit(struct ipq *qp)
+{
+	struct sk_buff *fp;
+	unsigned int sum_truesize = 0;
+
+	if (!mod_timer(&qp->q.timer, jiffies + qp->q.net->timeout)) {
+		atomic_inc(&qp->q.refcnt);
+		return -ETIMEDOUT;
+	}
+
+	fp = qp->q.fragments;
+	do {
+		struct sk_buff *xp = fp->next;
+
+		sum_truesize += fp->truesize;
+		kfree_skb(fp);
+		fp = xp;
+	} while (fp);
+	sub_frag_mem_limit(&qp->q, sum_truesize);
+
+	qp->q.flags = 0;
+	qp->q.len = 0;
+	qp->q.meat = 0;
+	qp->q.fragments = NULL;
+	qp->q.fragments_tail = NULL;
+	qp->iif = 0;
+	qp->ecn = 0;
+
+	return 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.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 - 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, ihl) == NULL)
+		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.flags |= 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.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, prev, dev);
+		skb->_skb_refdst = orefdst;
+		return err;
+	}
+
+	skb_dst_drop(skb);
+	return -EINPROGRESS;
+
+err:
+	kfree_skb(skb);
+	return err;
+}
+
+
+/* Build a new IP datagram from all its fragments. */
+
+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_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;
+}
+
+/* Process an incoming IP datagram fragment. */
+int ip_defrag(struct sk_buff *skb, u32 user)
+{
+	struct ipq *qp;
+	struct net *net;
+
+	net = skb->dev ? dev_net(skb->dev) : dev_net(skb_dst(skb)->dev);
+	IP_INC_STATS_BH(net, IPSTATS_MIB_REASMREQDS);
+
+	/* Lookup (or create) queue header */
+	if ((qp = ip_find(net, ip_hdr(skb), user)) != NULL) {
+		int ret;
+
+		spin_lock(&qp->q.lock);
+
+		ret = ip_frag_queue(qp, skb);
+
+		spin_unlock(&qp->q.lock);
+		ipq_put(qp);
+		return ret;
+	}
+
+	IP_INC_STATS_BH(net, IPSTATS_MIB_REASMFAILS);
+	kfree_skb(skb);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL(ip_defrag);
+
+struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
+{
+	struct iphdr iph;
+	int netoff;
+	u32 len;
+
+	if (skb->protocol != htons(ETH_P_IP))
+		return skb;
+
+	netoff = skb_network_offset(skb);
+
+	if (skb_copy_bits(skb, netoff, &iph, sizeof(iph)) < 0)
+		return skb;
+
+	if (iph.ihl < 5 || iph.version != 4)
+		return skb;
+
+	len = ntohs(iph.tot_len);
+	if (skb->len < netoff + len || len < (iph.ihl * 4))
+		return skb;
+
+	if (ip_is_fragment(&iph)) {
+		skb = skb_share_check(skb, GFP_ATOMIC);
+		if (skb) {
+			if (!pskb_may_pull(skb, netoff + iph.ihl * 4))
+				return skb;
+			if (pskb_trim_rcsum(skb, netoff + len))
+				return skb;
+			memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
+			if (ip_defrag(skb, user))
+				return NULL;
+			skb_clear_hash(skb);
+		}
+	}
+	return skb;
+}
+EXPORT_SYMBOL(ip_check_defrag);
+
+#ifdef CONFIG_SYSCTL
+static int zero;
+
+static struct ctl_table ip4_frags_ns_ctl_table[] = {
+	{
+		.procname	= "ipfrag_high_thresh",
+		.data		= &init_net.ipv4.frags.high_thresh,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &init_net.ipv4.frags.low_thresh
+	},
+	{
+		.procname	= "ipfrag_low_thresh",
+		.data		= &init_net.ipv4.frags.low_thresh,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &zero,
+		.extra2		= &init_net.ipv4.frags.high_thresh
+	},
+	{
+		.procname	= "ipfrag_time",
+		.data		= &init_net.ipv4.frags.timeout,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_jiffies,
+	},
+	{ }
+};
+
+/* secret interval has been deprecated */
+static int ip4_frags_secret_interval_unused;
+static struct ctl_table ip4_frags_ctl_table[] = {
+	{
+		.procname	= "ipfrag_secret_interval",
+		.data		= &ip4_frags_secret_interval_unused,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_jiffies,
+	},
+	{
+		.procname	= "ipfrag_max_dist",
+		.data		= &sysctl_ipfrag_max_dist,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &zero
+	},
+	{ }
+};
+
+static int __net_init ip4_frags_ns_ctl_register(struct net *net)
+{
+	struct ctl_table *table;
+	struct ctl_table_header *hdr;
+
+	table = ip4_frags_ns_ctl_table;
+	if (!net_eq(net, &init_net)) {
+		table = kmemdup(table, sizeof(ip4_frags_ns_ctl_table), GFP_KERNEL);
+		if (table == NULL)
+			goto err_alloc;
+
+		table[0].data = &net->ipv4.frags.high_thresh;
+		table[0].extra1 = &net->ipv4.frags.low_thresh;
+		table[0].extra2 = &init_net.ipv4.frags.high_thresh;
+		table[1].data = &net->ipv4.frags.low_thresh;
+		table[1].extra2 = &net->ipv4.frags.high_thresh;
+		table[2].data = &net->ipv4.frags.timeout;
+
+		/* Don't export sysctls to unprivileged users */
+		if (net->user_ns != &init_user_ns)
+			table[0].procname = NULL;
+	}
+
+	hdr = register_net_sysctl(net, "net/ipv4", table);
+	if (hdr == NULL)
+		goto err_reg;
+
+	net->ipv4.frags_hdr = hdr;
+	return 0;
+
+err_reg:
+	if (!net_eq(net, &init_net))
+		kfree(table);
+err_alloc:
+	return -ENOMEM;
+}
+
+static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net)
+{
+	struct ctl_table *table;
+
+	table = net->ipv4.frags_hdr->ctl_table_arg;
+	unregister_net_sysctl_table(net->ipv4.frags_hdr);
+	kfree(table);
+}
+
+static void __init ip4_frags_ctl_register(void)
+{
+	register_net_sysctl(&init_net, "net/ipv4", ip4_frags_ctl_table);
+}
+#else
+static inline int ip4_frags_ns_ctl_register(struct net *net)
+{
+	return 0;
+}
+
+static inline void ip4_frags_ns_ctl_unregister(struct net *net)
+{
+}
+
+static inline void __init ip4_frags_ctl_register(void)
+{
+}
+#endif
+
+static int __net_init ipv4_frags_init_net(struct net *net)
+{
+	/* Fragment cache limits.
+	 *
+	 * The fragment memory accounting code, (tries to) account for
+	 * the real memory usage, by measuring both the size of frag
+	 * queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue))
+	 * and the SKB's truesize.
+	 *
+	 * A 64K fragment consumes 129736 bytes (44*2944)+200
+	 * (1500 truesize == 2944, sizeof(struct ipq) == 200)
+	 *
+	 * We will commit 4MB at one time. Should we cross that limit
+	 * we will prune down to 3MB, making room for approx 8 big 64K
+	 * fragments 8x128k.
+	 */
+	net->ipv4.frags.high_thresh = 4 * 1024 * 1024;
+	net->ipv4.frags.low_thresh  = 3 * 1024 * 1024;
+	/*
+	 * Important NOTE! Fragment queue must be destroyed before MSL expires.
+	 * RFC791 is wrong proposing to prolongate timer each fragment arrival
+	 * by TTL.
+	 */
+	net->ipv4.frags.timeout = IP_FRAG_TIME;
+
+	inet_frags_init_net(&net->ipv4.frags);
+
+	return ip4_frags_ns_ctl_register(net);
+}
+
+static void __net_exit ipv4_frags_exit_net(struct net *net)
+{
+	ip4_frags_ns_ctl_unregister(net);
+	inet_frags_exit_net(&net->ipv4.frags, &ip4_frags);
+}
+
+static struct pernet_operations ip4_frags_ops = {
+	.init = ipv4_frags_init_net,
+	.exit = ipv4_frags_exit_net,
+};
+
+void __init ipfrag_init(void)
+{
+	ip4_frags_ctl_register();
+	register_pernet_subsys(&ip4_frags_ops);
+	ip4_frags.hashfn = ip4_hashfn;
+	ip4_frags.constructor = ip4_frag_init;
+	ip4_frags.destructor = ip4_frag_free;
+	ip4_frags.skb_free = NULL;
+	ip4_frags.qsize = sizeof(struct ipq);
+	ip4_frags.match = ip4_frag_match;
+	ip4_frags.frag_expire = ip_expire;
+	ip4_frags.frags_cache_name = ip_frag_cache_name;
+	if (inet_frags_init(&ip4_frags))
+		panic("IP: failed to allocate ip4_frags cache\n");
+}