1 files changed, 753 insertions, 0 deletions

diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
new file mode 100644
index 000000000..fb1535698
--- /dev/null
+++ b/net/ipv4/ip_fragment.c
@@ -0,0 +1,753 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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>
+#include <net/l3mdev.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 const char ip_frag_cache_name[] = "ip4-frags";
+
+/* Describe an entry in the "incomplete datagrams" queue. */
+struct ipq {
+	struct inet_frag_queue q;
+
+	u8		ecn; /* RFC3168 support */
+	u16		max_df_size; /* largest frag with DF set seen */
+	int             iif;
+	unsigned int    rid;
+	struct inet_peer *peer;
+};
+
+static u8 ip4_frag_ecn(u8 tos)
+{
+	return 1 << (tos & INET_ECN_MASK);
+}
+
+static struct inet_frags ip4_frags;
+
+static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb,
+			 struct sk_buff *prev_tail, struct net_device *dev);
+
+
+static void ip4_frag_init(struct inet_frag_queue *q, const void *a)
+{
+	struct ipq *qp = container_of(q, struct ipq, q);
+	struct net *net = q->fqdir->net;
+
+	const struct frag_v4_compare_key *key = a;
+
+	q->key.v4 = *key;
+	qp->ecn = 0;
+	qp->peer = q->fqdir->max_dist ?
+		inet_getpeer_v4(net->ipv4.peers, key->saddr, key->vif, 1) :
+		NULL;
+}
+
+static 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 void ipq_put(struct ipq *ipq)
+{
+	inet_frag_put(&ipq->q);
+}
+
+/* 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);
+}
+
+static bool frag_expire_skip_icmp(u32 user)
+{
+	return user == IP_DEFRAG_AF_PACKET ||
+	       ip_defrag_user_in_between(user, IP_DEFRAG_CONNTRACK_IN,
+					 __IP_DEFRAG_CONNTRACK_IN_END) ||
+	       ip_defrag_user_in_between(user, IP_DEFRAG_CONNTRACK_BRIDGE_IN,
+					 __IP_DEFRAG_CONNTRACK_BRIDGE_IN);
+}
+
+/*
+ * Oops, a fragment queue timed out.  Kill it and send an ICMP reply.
+ */
+static void ip_expire(struct timer_list *t)
+{
+	struct inet_frag_queue *frag = from_timer(frag, t, timer);
+	const struct iphdr *iph;
+	struct sk_buff *head = NULL;
+	struct net *net;
+	struct ipq *qp;
+	int err;
+
+	qp = container_of(frag, struct ipq, q);
+	net = qp->q.fqdir->net;
+
+	rcu_read_lock();
+
+	/* Paired with WRITE_ONCE() in fqdir_pre_exit(). */
+	if (READ_ONCE(qp->q.fqdir->dead))
+		goto out_rcu_unlock;
+
+	spin_lock(&qp->q.lock);
+
+	if (qp->q.flags & INET_FRAG_COMPLETE)
+		goto out;
+
+	ipq_kill(qp);
+	__IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
+	__IP_INC_STATS(net, IPSTATS_MIB_REASMTIMEOUT);
+
+	if (!(qp->q.flags & INET_FRAG_FIRST_IN))
+		goto out;
+
+	/* sk_buff::dev and sk_buff::rbnode are unionized. So we
+	 * pull the head out of the tree in order to be able to
+	 * deal with head->dev.
+	 */
+	head = inet_frag_pull_head(&qp->q);
+	if (!head)
+		goto out;
+	head->dev = dev_get_by_index_rcu(net, qp->iif);
+	if (!head->dev)
+		goto out;
+
+
+	/* 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;
+
+	/* Only an end host needs to send an ICMP
+	 * "Fragment Reassembly Timeout" message, per RFC792.
+	 */
+	if (frag_expire_skip_icmp(qp->q.key.v4.user) &&
+	    (skb_rtable(head)->rt_type != RTN_LOCAL))
+		goto out;
+
+	spin_unlock(&qp->q.lock);
+	icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0);
+	goto out_rcu_unlock;
+
+out:
+	spin_unlock(&qp->q.lock);
+out_rcu_unlock:
+	rcu_read_unlock();
+	kfree_skb(head);
+	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 struct ipq *ip_find(struct net *net, struct iphdr *iph,
+			   u32 user, int vif)
+{
+	struct frag_v4_compare_key key = {
+		.saddr = iph->saddr,
+		.daddr = iph->daddr,
+		.user = user,
+		.vif = vif,
+		.id = iph->id,
+		.protocol = iph->protocol,
+	};
+	struct inet_frag_queue *q;
+
+	q = inet_frag_find(net->ipv4.fqdir, &key);
+	if (!q)
+		return NULL;
+
+	return container_of(q, struct ipq, q);
+}
+
+/* Is the fragment too far ahead to be part of ipq? */
+static int ip_frag_too_far(struct ipq *qp)
+{
+	struct inet_peer *peer = qp->peer;
+	unsigned int max = qp->q.fqdir->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_tail && (end - start) > max;
+
+	if (rc)
+		__IP_INC_STATS(qp->q.fqdir->net, IPSTATS_MIB_REASMFAILS);
+
+	return rc;
+}
+
+static int ip_frag_reinit(struct ipq *qp)
+{
+	unsigned int sum_truesize = 0;
+
+	if (!mod_timer(&qp->q.timer, jiffies + qp->q.fqdir->timeout)) {
+		refcount_inc(&qp->q.refcnt);
+		return -ETIMEDOUT;
+	}
+
+	sum_truesize = inet_frag_rbtree_purge(&qp->q.rb_fragments);
+	sub_frag_mem_limit(qp->q.fqdir, sum_truesize);
+
+	qp->q.flags = 0;
+	qp->q.len = 0;
+	qp->q.meat = 0;
+	qp->q.rb_fragments = RB_ROOT;
+	qp->q.fragments_tail = NULL;
+	qp->q.last_run_head = 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 net *net = qp->q.fqdir->net;
+	int ihl, end, flags, offset;
+	struct sk_buff *prev_tail;
+	struct net_device *dev;
+	unsigned int fragsize;
+	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 discard_qp;
+		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 discard_qp;
+			qp->q.len = end;
+		}
+	}
+	if (end == offset)
+		goto discard_qp;
+
+	err = -ENOMEM;
+	if (!pskb_pull(skb, skb_network_offset(skb) + ihl))
+		goto discard_qp;
+
+	err = pskb_trim_rcsum(skb, end - offset);
+	if (err)
+		goto discard_qp;
+
+	/* Note : skb->rbnode and skb->dev share the same location. */
+	dev = skb->dev;
+	/* Makes sure compiler wont do silly aliasing games */
+	barrier();
+
+	prev_tail = qp->q.fragments_tail;
+	err = inet_frag_queue_insert(&qp->q, skb, offset, end);
+	if (err)
+		goto insert_error;
+
+	if (dev)
+		qp->iif = dev->ifindex;
+
+	qp->q.stamp = skb->tstamp;
+	qp->q.mono_delivery_time = skb->mono_delivery_time;
+	qp->q.meat += skb->len;
+	qp->ecn |= ecn;
+	add_frag_mem_limit(qp->q.fqdir, 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;
+		if (err)
+			inet_frag_kill(&qp->q);
+		return err;
+	}
+
+	skb_dst_drop(skb);
+	return -EINPROGRESS;
+
+insert_error:
+	if (err == IPFRAG_DUP) {
+		kfree_skb(skb);
+		return -EINVAL;
+	}
+	err = -EINVAL;
+	__IP_INC_STATS(net, IPSTATS_MIB_REASM_OVERLAPS);
+discard_qp:
+	inet_frag_kill(&qp->q);
+	__IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
+err:
+	kfree_skb(skb);
+	return err;
+}
+
+static bool ip_frag_coalesce_ok(const struct ipq *qp)
+{
+	return qp->q.key.v4.user == IP_DEFRAG_LOCAL_DELIVER;
+}
+
+/* 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 = qp->q.fqdir->net;
+	struct iphdr *iph;
+	void *reasm_data;
+	int len, 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. */
+	reasm_data = inet_frag_reasm_prepare(&qp->q, skb, prev_tail);
+	if (!reasm_data)
+		goto out_nomem;
+
+	len = ip_hdrlen(skb) + qp->q.len;
+	err = -E2BIG;
+	if (len > 65535)
+		goto out_oversize;
+
+	inet_frag_reasm_finish(&qp->q, skb, reasm_data,
+			       ip_frag_coalesce_ok(qp));
+
+	skb->dev = dev;
+	IPCB(skb)->frag_max_size = max(qp->max_df_size, qp->q.max_size);
+
+	iph = ip_hdr(skb);
+	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(skb)->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.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;
+}
+
+/* Process an incoming IP datagram fragment. */
+int ip_defrag(struct net *net, struct sk_buff *skb, u32 user)
+{
+	struct net_device *dev = skb->dev ? : skb_dst(skb)->dev;
+	int vif = l3mdev_master_ifindex_rcu(dev);
+	struct ipq *qp;
+
+	__IP_INC_STATS(net, IPSTATS_MIB_REASMREQDS);
+	skb_orphan(skb);
+
+	/* Lookup (or create) queue header */
+	qp = ip_find(net, ip_hdr(skb), user, vif);
+	if (qp) {
+		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(net, IPSTATS_MIB_REASMFAILS);
+	kfree_skb(skb);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL(ip_defrag);
+
+struct sk_buff *ip_check_defrag(struct net *net, 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)) {
+				kfree_skb(skb);
+				return NULL;
+			}
+			if (pskb_trim_rcsum(skb, netoff + len)) {
+				kfree_skb(skb);
+				return NULL;
+			}
+			memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
+			if (ip_defrag(net, skb, user))
+				return NULL;
+			skb_clear_hash(skb);
+		}
+	}
+	return skb;
+}
+EXPORT_SYMBOL(ip_check_defrag);
+
+#ifdef CONFIG_SYSCTL
+static int dist_min;
+
+static struct ctl_table ip4_frags_ns_ctl_table[] = {
+	{
+		.procname	= "ipfrag_high_thresh",
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= proc_doulongvec_minmax,
+	},
+	{
+		.procname	= "ipfrag_low_thresh",
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= proc_doulongvec_minmax,
+	},
+	{
+		.procname	= "ipfrag_time",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_jiffies,
+	},
+	{
+		.procname	= "ipfrag_max_dist",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &dist_min,
+	},
+	{ }
+};
+
+/* 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,
+	},
+	{ }
+};
+
+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)
+			goto err_alloc;
+
+	}
+	table[0].data	= &net->ipv4.fqdir->high_thresh;
+	table[0].extra1	= &net->ipv4.fqdir->low_thresh;
+	table[1].data	= &net->ipv4.fqdir->low_thresh;
+	table[1].extra2	= &net->ipv4.fqdir->high_thresh;
+	table[2].data	= &net->ipv4.fqdir->timeout;
+	table[3].data	= &net->ipv4.fqdir->max_dist;
+
+	hdr = register_net_sysctl(net, "net/ipv4", table);
+	if (!hdr)
+		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 int ip4_frags_ns_ctl_register(struct net *net)
+{
+	return 0;
+}
+
+static void ip4_frags_ns_ctl_unregister(struct net *net)
+{
+}
+
+static void __init ip4_frags_ctl_register(void)
+{
+}
+#endif
+
+static int __net_init ipv4_frags_init_net(struct net *net)
+{
+	int res;
+
+	res = fqdir_init(&net->ipv4.fqdir, &ip4_frags, net);
+	if (res < 0)
+		return res;
+	/* 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.fqdir->high_thresh = 4 * 1024 * 1024;
+	net->ipv4.fqdir->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.fqdir->timeout = IP_FRAG_TIME;
+
+	net->ipv4.fqdir->max_dist = 64;
+
+	res = ip4_frags_ns_ctl_register(net);
+	if (res < 0)
+		fqdir_exit(net->ipv4.fqdir);
+	return res;
+}
+
+static void __net_exit ipv4_frags_pre_exit_net(struct net *net)
+{
+	fqdir_pre_exit(net->ipv4.fqdir);
+}
+
+static void __net_exit ipv4_frags_exit_net(struct net *net)
+{
+	ip4_frags_ns_ctl_unregister(net);
+	fqdir_exit(net->ipv4.fqdir);
+}
+
+static struct pernet_operations ip4_frags_ops = {
+	.init		= ipv4_frags_init_net,
+	.pre_exit	= ipv4_frags_pre_exit_net,
+	.exit		= ipv4_frags_exit_net,
+};
+
+
+static u32 ip4_key_hashfn(const void *data, u32 len, u32 seed)
+{
+	return jhash2(data,
+		      sizeof(struct frag_v4_compare_key) / sizeof(u32), seed);
+}
+
+static u32 ip4_obj_hashfn(const void *data, u32 len, u32 seed)
+{
+	const struct inet_frag_queue *fq = data;
+
+	return jhash2((const u32 *)&fq->key.v4,
+		      sizeof(struct frag_v4_compare_key) / sizeof(u32), seed);
+}
+
+static int ip4_obj_cmpfn(struct rhashtable_compare_arg *arg, const void *ptr)
+{
+	const struct frag_v4_compare_key *key = arg->key;
+	const struct inet_frag_queue *fq = ptr;
+
+	return !!memcmp(&fq->key, key, sizeof(*key));
+}
+
+static const struct rhashtable_params ip4_rhash_params = {
+	.head_offset		= offsetof(struct inet_frag_queue, node),
+	.key_offset		= offsetof(struct inet_frag_queue, key),
+	.key_len		= sizeof(struct frag_v4_compare_key),
+	.hashfn			= ip4_key_hashfn,
+	.obj_hashfn		= ip4_obj_hashfn,
+	.obj_cmpfn		= ip4_obj_cmpfn,
+	.automatic_shrinking	= true,
+};
+
+void __init ipfrag_init(void)
+{
+	ip4_frags.constructor = ip4_frag_init;
+	ip4_frags.destructor = ip4_frag_free;
+	ip4_frags.qsize = sizeof(struct ipq);
+	ip4_frags.frag_expire = ip_expire;
+	ip4_frags.frags_cache_name = ip_frag_cache_name;
+	ip4_frags.rhash_params = ip4_rhash_params;
+	if (inet_frags_init(&ip4_frags))
+		panic("IP: failed to allocate ip4_frags cache\n");
+	ip4_frags_ctl_register();
+	register_pernet_subsys(&ip4_frags_ops);
+}