v4.19.13 snapshot.
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
new file mode 100644
index 0000000..f686d77
--- /dev/null
+++ b/net/ipv4/ip_fragment.c
@@ -0,0 +1,978 @@
+// 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";
+
+/* Use skb->cb to track consecutive/adjacent fragments coming at
+ * the end of the queue. Nodes in the rb-tree queue will
+ * contain "runs" of one or more adjacent fragments.
+ *
+ * Invariants:
+ * - next_frag is NULL at the tail of a "run";
+ * - the head of a "run" has the sum of all fragment lengths in frag_run_len.
+ */
+struct ipfrag_skb_cb {
+ struct inet_skb_parm h;
+ struct sk_buff *next_frag;
+ int frag_run_len;
+};
+
+#define FRAG_CB(skb) ((struct ipfrag_skb_cb *)((skb)->cb))
+
+static void ip4_frag_init_run(struct sk_buff *skb)
+{
+ BUILD_BUG_ON(sizeof(struct ipfrag_skb_cb) > sizeof(skb->cb));
+
+ FRAG_CB(skb)->next_frag = NULL;
+ FRAG_CB(skb)->frag_run_len = skb->len;
+}
+
+/* Append skb to the last "run". */
+static void ip4_frag_append_to_last_run(struct inet_frag_queue *q,
+ struct sk_buff *skb)
+{
+ RB_CLEAR_NODE(&skb->rbnode);
+ FRAG_CB(skb)->next_frag = NULL;
+
+ FRAG_CB(q->last_run_head)->frag_run_len += skb->len;
+ FRAG_CB(q->fragments_tail)->next_frag = skb;
+ q->fragments_tail = skb;
+}
+
+/* Create a new "run" with the skb. */
+static void ip4_frag_create_run(struct inet_frag_queue *q, struct sk_buff *skb)
+{
+ if (q->last_run_head)
+ rb_link_node(&skb->rbnode, &q->last_run_head->rbnode,
+ &q->last_run_head->rbnode.rb_right);
+ else
+ rb_link_node(&skb->rbnode, NULL, &q->rb_fragments.rb_node);
+ rb_insert_color(&skb->rbnode, &q->rb_fragments);
+
+ ip4_frag_init_run(skb);
+ q->fragments_tail = skb;
+ q->last_run_head = skb;
+}
+
+/* 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 netns_ipv4 *ipv4 = container_of(q->net, struct netns_ipv4,
+ frags);
+ struct net *net = container_of(ipv4, struct net, ipv4);
+
+ const struct frag_v4_compare_key *key = a;
+
+ q->key.v4 = *key;
+ qp->ecn = 0;
+ qp->peer = q->net->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 = container_of(qp->q.net, struct net, ipv4.frags);
+
+ rcu_read_lock();
+ 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.
+ */
+ if (qp->q.fragments) {
+ head = qp->q.fragments;
+ qp->q.fragments = head->next;
+ } else {
+ head = skb_rb_first(&qp->q.rb_fragments);
+ if (!head)
+ goto out;
+ if (FRAG_CB(head)->next_frag)
+ rb_replace_node(&head->rbnode,
+ &FRAG_CB(head)->next_frag->rbnode,
+ &qp->q.rb_fragments);
+ else
+ rb_erase(&head->rbnode, &qp->q.rb_fragments);
+ memset(&head->rbnode, 0, sizeof(head->rbnode));
+ barrier();
+ }
+ if (head == qp->q.fragments_tail)
+ qp->q.fragments_tail = NULL;
+
+ sub_frag_mem_limit(qp->q.net, head->truesize);
+
+ 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();
+ if (head)
+ 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.frags, &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.net->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) {
+ struct net *net;
+
+ net = container_of(qp->q.net, struct net, ipv4.frags);
+ __IP_INC_STATS(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.net->timeout)) {
+ refcount_inc(&qp->q.refcnt);
+ return -ETIMEDOUT;
+ }
+
+ sum_truesize = inet_frag_rbtree_purge(&qp->q.rb_fragments);
+ sub_frag_mem_limit(qp->q.net, sum_truesize);
+
+ qp->q.flags = 0;
+ qp->q.len = 0;
+ qp->q.meat = 0;
+ qp->q.fragments = NULL;
+ 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 = 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;
+}
+
+/* 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 delta;
+ 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;
+
+ delta = - head->truesize;
+
+ /* Head of list must not be cloned. */
+ if (skb_unclone(head, GFP_ATOMIC))
+ goto out_nomem;
+
+ delta += head->truesize;
+ if (delta)
+ add_frag_mem_limit(qp->q.net, delta);
+
+ /* 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));
+ fp->sk = NULL;
+ 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;
+}
+
+/* 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);
+
+unsigned int inet_frag_rbtree_purge(struct rb_root *root)
+{
+ struct rb_node *p = rb_first(root);
+ unsigned int sum = 0;
+
+ while (p) {
+ struct sk_buff *skb = rb_entry(p, struct sk_buff, rbnode);
+
+ p = rb_next(p);
+ rb_erase(&skb->rbnode, root);
+ while (skb) {
+ struct sk_buff *next = FRAG_CB(skb)->next_frag;
+
+ sum += skb->truesize;
+ kfree_skb(skb);
+ skb = next;
+ }
+ }
+ return sum;
+}
+EXPORT_SYMBOL(inet_frag_rbtree_purge);
+
+#ifdef CONFIG_SYSCTL
+static int dist_min;
+
+static struct ctl_table ip4_frags_ns_ctl_table[] = {
+ {
+ .procname = "ipfrag_high_thresh",
+ .data = &init_net.ipv4.frags.high_thresh,
+ .maxlen = sizeof(unsigned long),
+ .mode = 0644,
+ .proc_handler = proc_doulongvec_minmax,
+ .extra1 = &init_net.ipv4.frags.low_thresh
+ },
+ {
+ .procname = "ipfrag_low_thresh",
+ .data = &init_net.ipv4.frags.low_thresh,
+ .maxlen = sizeof(unsigned long),
+ .mode = 0644,
+ .proc_handler = proc_doulongvec_minmax,
+ .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,
+ },
+ {
+ .procname = "ipfrag_max_dist",
+ .data = &init_net.ipv4.frags.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.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;
+ table[3].data = &net->ipv4.frags.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;
+
+ /* 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;
+
+ net->ipv4.frags.max_dist = 64;
+ net->ipv4.frags.f = &ip4_frags;
+
+ res = inet_frags_init_net(&net->ipv4.frags);
+ if (res < 0)
+ return res;
+ res = ip4_frags_ns_ctl_register(net);
+ if (res < 0)
+ inet_frags_exit_net(&net->ipv4.frags);
+ return res;
+}
+
+static void __net_exit ipv4_frags_exit_net(struct net *net)
+{
+ ip4_frags_ns_ctl_unregister(net);
+ inet_frags_exit_net(&net->ipv4.frags);
+}
+
+static struct pernet_operations ip4_frags_ops = {
+ .init = ipv4_frags_init_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);
+}