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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /net/ipv4/ip_fragment.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/ipv4/ip_fragment.c')
-rw-r--r--net/ipv4/ip_fragment.c761
1 files changed, 761 insertions, 0 deletions
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
new file mode 100644
index 0000000000..a4941f53b5
--- /dev/null
+++ b/net/ipv4/ip_fragment.c
@@ -0,0 +1,761 @@
+// 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;
+
+ qp->q.flags |= INET_FRAG_DROP;
+ 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_reason(head, SKB_DROP_REASON_FRAG_REASM_TIMEOUT);
+ 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,
+ SKB_DROP_REASON_FRAG_TOO_FAR);
+ 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;
+ SKB_DR(reason);
+ u8 ecn;
+
+ /* If reassembly is already done, @skb must be a duplicate frag. */
+ if (qp->q.flags & INET_FRAG_COMPLETE) {
+ SKB_DR_SET(reason, DUP_FRAG);
+ 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) {
+ SKB_DR_SET(reason, DUP_FRAG);
+ err = -EINVAL;
+ goto err;
+ }
+ 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_reason(skb, reason);
+ 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_sz(net, "net/ipv4", table,
+ ARRAY_SIZE(ip4_frags_ns_ctl_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);
+}