1 files changed, 771 insertions, 0 deletions

diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
new file mode 100644
index 000000000000..59e7c6317872
--- /dev/null
+++ b/net/ipv6/reassembly.c
@@ -0,0 +1,771 @@
+/*
+ *      IPv6 fragment reassembly
+ *      Linux INET6 implementation 
+ *
+ *      Authors:
+ *      Pedro Roque             <roque@di.fc.ul.pt>     
+ *
+ *      $Id: reassembly.c,v 1.26 2001/03/07 22:00:57 davem Exp $
+ *
+ *      Based on: net/ipv4/ip_fragment.c
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+/* 
+ *      Fixes:  
+ *      Andi Kleen      Make it work with multiple hosts.
+ *                      More RFC compliance.
+ *
+ *      Horst von Brand Add missing #include <linux/string.h>
+ *      Alexey Kuznetsov        SMP races, threading, cleanup.
+ *      Patrick McHardy         LRU queue of frag heads for evictor.
+ *      Mitsuru KANDA @USAGI    Register inet6_protocol{}.
+ *      David Stevens and
+ *      YOSHIFUJI,H. @USAGI     Always remove fragment header to
+ *                              calculate ICV correctly.
+ */
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/jiffies.h>
+#include <linux/net.h>
+#include <linux/list.h>
+#include <linux/netdevice.h>
+#include <linux/in6.h>
+#include <linux/ipv6.h>
+#include <linux/icmpv6.h>
+#include <linux/random.h>
+#include <linux/jhash.h>
+
+#include <net/sock.h>
+#include <net/snmp.h>
+
+#include <net/ipv6.h>
+#include <net/protocol.h>
+#include <net/transp_v6.h>
+#include <net/rawv6.h>
+#include <net/ndisc.h>
+#include <net/addrconf.h>
+
+int sysctl_ip6frag_high_thresh = 256*1024;
+int sysctl_ip6frag_low_thresh = 192*1024;
+
+int sysctl_ip6frag_time = IPV6_FRAG_TIMEOUT;
+
+struct ip6frag_skb_cb
+{
+        struct inet6_skb_parm   h;
+        int                     offset;
+};
+
+#define FRAG6_CB(skb)   ((struct ip6frag_skb_cb*)((skb)->cb))
+
+
+/*
+ *      Equivalent of ipv4 struct ipq
+ */
+
+struct frag_queue
+{
+        struct frag_queue       *next;
+        struct list_head lru_list;              /* lru list member      */
+
+        __u32                   id;             /* fragment id          */
+        struct in6_addr         saddr;
+        struct in6_addr         daddr;
+
+        spinlock_t              lock;
+        atomic_t                refcnt;
+        struct timer_list       timer;          /* expire timer         */
+        struct sk_buff          *fragments;
+        int                     len;
+        int                     meat;
+        int                     iif;
+        struct timeval          stamp;
+        unsigned int            csum;
+        __u8                    last_in;        /* has first/last segment arrived? */
+#define COMPLETE                4
+#define FIRST_IN                2
+#define LAST_IN                 1
+        __u16                   nhoffset;
+        struct frag_queue       **pprev;
+};
+
+/* Hash table. */
+
+#define IP6Q_HASHSZ     64
+
+static struct frag_queue *ip6_frag_hash[IP6Q_HASHSZ];
+static DEFINE_RWLOCK(ip6_frag_lock);
+static u32 ip6_frag_hash_rnd;
+static LIST_HEAD(ip6_frag_lru_list);
+int ip6_frag_nqueues = 0;
+
+static __inline__ void __fq_unlink(struct frag_queue *fq)
+{
+        if(fq->next)
+                fq->next->pprev = fq->pprev;
+        *fq->pprev = fq->next;
+        list_del(&fq->lru_list);
+        ip6_frag_nqueues--;
+}
+
+static __inline__ void fq_unlink(struct frag_queue *fq)
+{
+        write_lock(&ip6_frag_lock);
+        __fq_unlink(fq);
+        write_unlock(&ip6_frag_lock);
+}
+
+static unsigned int ip6qhashfn(u32 id, struct in6_addr *saddr,
+                               struct in6_addr *daddr)
+{
+        u32 a, b, c;
+
+        a = saddr->s6_addr32[0];
+        b = saddr->s6_addr32[1];
+        c = saddr->s6_addr32[2];
+
+        a += JHASH_GOLDEN_RATIO;
+        b += JHASH_GOLDEN_RATIO;
+        c += ip6_frag_hash_rnd;
+        __jhash_mix(a, b, c);
+
+        a += saddr->s6_addr32[3];
+        b += daddr->s6_addr32[0];
+        c += daddr->s6_addr32[1];
+        __jhash_mix(a, b, c);
+
+        a += daddr->s6_addr32[2];
+        b += daddr->s6_addr32[3];
+        c += id;
+        __jhash_mix(a, b, c);
+
+        return c & (IP6Q_HASHSZ - 1);
+}
+
+static struct timer_list ip6_frag_secret_timer;
+int sysctl_ip6frag_secret_interval = 10 * 60 * HZ;
+
+static void ip6_frag_secret_rebuild(unsigned long dummy)
+{
+        unsigned long now = jiffies;
+        int i;
+
+        write_lock(&ip6_frag_lock);
+        get_random_bytes(&ip6_frag_hash_rnd, sizeof(u32));
+        for (i = 0; i < IP6Q_HASHSZ; i++) {
+                struct frag_queue *q;
+
+                q = ip6_frag_hash[i];
+                while (q) {
+                        struct frag_queue *next = q->next;
+                        unsigned int hval = ip6qhashfn(q->id,
+                                                       &q->saddr,
+                                                       &q->daddr);
+
+                        if (hval != i) {
+                                /* Unlink. */
+                                if (q->next)
+                                        q->next->pprev = q->pprev;
+                                *q->pprev = q->next;
+
+                                /* Relink to new hash chain. */
+                                if ((q->next = ip6_frag_hash[hval]) != NULL)
+                                        q->next->pprev = &q->next;
+                                ip6_frag_hash[hval] = q;
+                                q->pprev = &ip6_frag_hash[hval];
+                        }
+
+                        q = next;
+                }
+        }
+        write_unlock(&ip6_frag_lock);
+
+        mod_timer(&ip6_frag_secret_timer, now + sysctl_ip6frag_secret_interval);
+}
+
+atomic_t ip6_frag_mem = ATOMIC_INIT(0);
+
+/* Memory Tracking Functions. */
+static inline void frag_kfree_skb(struct sk_buff *skb, int *work)
+{
+        if (work)
+                *work -= skb->truesize;
+        atomic_sub(skb->truesize, &ip6_frag_mem);
+        kfree_skb(skb);
+}
+
+static inline void frag_free_queue(struct frag_queue *fq, int *work)
+{
+        if (work)
+                *work -= sizeof(struct frag_queue);
+        atomic_sub(sizeof(struct frag_queue), &ip6_frag_mem);
+        kfree(fq);
+}
+
+static inline struct frag_queue *frag_alloc_queue(void)
+{
+        struct frag_queue *fq = kmalloc(sizeof(struct frag_queue), GFP_ATOMIC);
+
+        if(!fq)
+                return NULL;
+        atomic_add(sizeof(struct frag_queue), &ip6_frag_mem);
+        return fq;
+}
+
+/* Destruction primitives. */
+
+/* Complete destruction of fq. */
+static void ip6_frag_destroy(struct frag_queue *fq, int *work)
+{
+        struct sk_buff *fp;
+
+        BUG_TRAP(fq->last_in&COMPLETE);
+        BUG_TRAP(del_timer(&fq->timer) == 0);
+
+        /* Release all fragment data. */
+        fp = fq->fragments;
+        while (fp) {
+                struct sk_buff *xp = fp->next;
+
+                frag_kfree_skb(fp, work);
+                fp = xp;
+        }
+
+        frag_free_queue(fq, work);
+}
+
+static __inline__ void fq_put(struct frag_queue *fq, int *work)
+{
+        if (atomic_dec_and_test(&fq->refcnt))
+                ip6_frag_destroy(fq, work);
+}
+
+/* Kill fq entry. It is not destroyed immediately,
+ * because caller (and someone more) holds reference count.
+ */
+static __inline__ void fq_kill(struct frag_queue *fq)
+{
+        if (del_timer(&fq->timer))
+                atomic_dec(&fq->refcnt);
+
+        if (!(fq->last_in & COMPLETE)) {
+                fq_unlink(fq);
+                atomic_dec(&fq->refcnt);
+                fq->last_in |= COMPLETE;
+        }
+}
+
+static void ip6_evictor(void)
+{
+        struct frag_queue *fq;
+        struct list_head *tmp;
+        int work;
+
+        work = atomic_read(&ip6_frag_mem) - sysctl_ip6frag_low_thresh;
+        if (work <= 0)
+                return;
+
+        while(work > 0) {
+                read_lock(&ip6_frag_lock);
+                if (list_empty(&ip6_frag_lru_list)) {
+                        read_unlock(&ip6_frag_lock);
+                        return;
+                }
+                tmp = ip6_frag_lru_list.next;
+                fq = list_entry(tmp, struct frag_queue, lru_list);
+                atomic_inc(&fq->refcnt);
+                read_unlock(&ip6_frag_lock);
+
+                spin_lock(&fq->lock);
+                if (!(fq->last_in&COMPLETE))
+                        fq_kill(fq);
+                spin_unlock(&fq->lock);
+
+                fq_put(fq, &work);
+                IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
+        }
+}
+
+static void ip6_frag_expire(unsigned long data)
+{
+        struct frag_queue *fq = (struct frag_queue *) data;
+
+        spin_lock(&fq->lock);
+
+        if (fq->last_in & COMPLETE)
+                goto out;
+
+        fq_kill(fq);
+
+        IP6_INC_STATS_BH(IPSTATS_MIB_REASMTIMEOUT);
+        IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
+
+        /* Send error only if the first segment arrived. */
+        if (fq->last_in&FIRST_IN && fq->fragments) {
+                struct net_device *dev = dev_get_by_index(fq->iif);
+
+                /*
+                   But use as source device on which LAST ARRIVED
+                   segment was received. And do not use fq->dev
+                   pointer directly, device might already disappeared.
+                 */
+                if (dev) {
+                        fq->fragments->dev = dev;
+                        icmpv6_send(fq->fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0,
+                                    dev);
+                        dev_put(dev);
+                }
+        }
+out:
+        spin_unlock(&fq->lock);
+        fq_put(fq, NULL);
+}
+
+/* Creation primitives. */
+
+
+static struct frag_queue *ip6_frag_intern(unsigned int hash,
+                                          struct frag_queue *fq_in)
+{
+        struct frag_queue *fq;
+
+        write_lock(&ip6_frag_lock);
+#ifdef CONFIG_SMP
+        for (fq = ip6_frag_hash[hash]; fq; fq = fq->next) {
+                if (fq->id == fq_in->id && 
+                    ipv6_addr_equal(&fq_in->saddr, &fq->saddr) &&
+                    ipv6_addr_equal(&fq_in->daddr, &fq->daddr)) {
+                        atomic_inc(&fq->refcnt);
+                        write_unlock(&ip6_frag_lock);
+                        fq_in->last_in |= COMPLETE;
+                        fq_put(fq_in, NULL);
+                        return fq;
+                }
+        }
+#endif
+        fq = fq_in;
+
+        if (!mod_timer(&fq->timer, jiffies + sysctl_ip6frag_time))
+                atomic_inc(&fq->refcnt);
+
+        atomic_inc(&fq->refcnt);
+        if((fq->next = ip6_frag_hash[hash]) != NULL)
+                fq->next->pprev = &fq->next;
+        ip6_frag_hash[hash] = fq;
+        fq->pprev = &ip6_frag_hash[hash];
+        INIT_LIST_HEAD(&fq->lru_list);
+        list_add_tail(&fq->lru_list, &ip6_frag_lru_list);
+        ip6_frag_nqueues++;
+        write_unlock(&ip6_frag_lock);
+        return fq;
+}
+
+
+static struct frag_queue *
+ip6_frag_create(unsigned int hash, u32 id, struct in6_addr *src, struct in6_addr *dst)
+{
+        struct frag_queue *fq;
+
+        if ((fq = frag_alloc_queue()) == NULL)
+                goto oom;
+
+        memset(fq, 0, sizeof(struct frag_queue));
+
+        fq->id = id;
+        ipv6_addr_copy(&fq->saddr, src);
+        ipv6_addr_copy(&fq->daddr, dst);
+
+        init_timer(&fq->timer);
+        fq->timer.function = ip6_frag_expire;
+        fq->timer.data = (long) fq;
+        spin_lock_init(&fq->lock);
+        atomic_set(&fq->refcnt, 1);
+
+        return ip6_frag_intern(hash, fq);
+
+oom:
+        IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
+        return NULL;
+}
+
+static __inline__ struct frag_queue *
+fq_find(u32 id, struct in6_addr *src, struct in6_addr *dst)
+{
+        struct frag_queue *fq;
+        unsigned int hash = ip6qhashfn(id, src, dst);
+
+        read_lock(&ip6_frag_lock);
+        for(fq = ip6_frag_hash[hash]; fq; fq = fq->next) {
+                if (fq->id == id && 
+                    ipv6_addr_equal(src, &fq->saddr) &&
+                    ipv6_addr_equal(dst, &fq->daddr)) {
+                        atomic_inc(&fq->refcnt);
+                        read_unlock(&ip6_frag_lock);
+                        return fq;
+                }
+        }
+        read_unlock(&ip6_frag_lock);
+
+        return ip6_frag_create(hash, id, src, dst);
+}
+
+
+static void ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, 
+                           struct frag_hdr *fhdr, int nhoff)
+{
+        struct sk_buff *prev, *next;
+        int offset, end;
+
+        if (fq->last_in & COMPLETE)
+                goto err;
+
+        offset = ntohs(fhdr->frag_off) & ~0x7;
+        end = offset + (ntohs(skb->nh.ipv6h->payload_len) -
+                        ((u8 *) (fhdr + 1) - (u8 *) (skb->nh.ipv6h + 1)));
+
+        if ((unsigned int)end > IPV6_MAXPLEN) {
+                IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+                icmpv6_param_prob(skb,ICMPV6_HDR_FIELD, (u8*)&fhdr->frag_off - skb->nh.raw);
+                return;
+        }
+
+        if (skb->ip_summed == CHECKSUM_HW)
+                skb->csum = csum_sub(skb->csum,
+                                     csum_partial(skb->nh.raw, (u8*)(fhdr+1)-skb->nh.raw, 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->len ||
+                    ((fq->last_in & LAST_IN) && end != fq->len))
+                        goto err;
+                fq->last_in |= LAST_IN;
+                fq->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_BH(IPSTATS_MIB_INHDRERRORS);
+                        icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 
+                                          offsetof(struct ipv6hdr, payload_len));
+                        return;
+                }
+                if (end > fq->len) {
+                        /* Some bits beyond end -> corruption. */
+                        if (fq->last_in & LAST_IN)
+                                goto err;
+                        fq->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 (end-offset < skb->len) {
+                if (pskb_trim(skb, end - offset))
+                        goto err;
+                if (skb->ip_summed != CHECKSUM_UNNECESSARY)
+                        skb->ip_summed = CHECKSUM_NONE;
+        }
+
+        /* 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 = NULL;
+        for(next = fq->fragments; next != NULL; next = next->next) {
+                if (FRAG6_CB(next)->offset >= offset)
+                        break;  /* bingo! */
+                prev = next;
+        }
+
+        /* 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 = (FRAG6_CB(prev)->offset + prev->len) - offset;
+
+                if (i > 0) {
+                        offset += i;
+                        if (end <= offset)
+                                goto err;
+                        if (!pskb_pull(skb, i))
+                                goto err;
+                        if (skb->ip_summed != CHECKSUM_UNNECESSARY)
+                                skb->ip_summed = CHECKSUM_NONE;
+                }
+        }
+
+        /* Look for overlap with succeeding segments.
+         * If we can merge fragments, do it.
+         */
+        while (next && FRAG6_CB(next)->offset < end) {
+                int i = end - FRAG6_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;
+                        FRAG6_CB(next)->offset += i;    /* next fragment */
+                        fq->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
+                                fq->fragments = next;
+
+                        fq->meat -= free_it->len;
+                        frag_kfree_skb(free_it, NULL);
+                }
+        }
+
+        FRAG6_CB(skb)->offset = offset;
+
+        /* Insert this fragment in the chain of fragments. */
+        skb->next = next;
+        if (prev)
+                prev->next = skb;
+        else
+                fq->fragments = skb;
+
+        if (skb->dev)
+                fq->iif = skb->dev->ifindex;
+        skb->dev = NULL;
+        fq->stamp = skb->stamp;
+        fq->meat += skb->len;
+        atomic_add(skb->truesize, &ip6_frag_mem);
+
+        /* The first fragment.
+         * nhoffset is obtained from the first fragment, of course.
+         */
+        if (offset == 0) {
+                fq->nhoffset = nhoff;
+                fq->last_in |= FIRST_IN;
+        }
+        write_lock(&ip6_frag_lock);
+        list_move_tail(&fq->lru_list, &ip6_frag_lru_list);
+        write_unlock(&ip6_frag_lock);
+        return;
+
+err:
+        IP6_INC_STATS(IPSTATS_MIB_REASMFAILS);
+        kfree_skb(skb);
+}
+
+/*
+ *      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 **skb_in,
+                          unsigned int *nhoffp,
+                          struct net_device *dev)
+{
+        struct sk_buff *fp, *head = fq->fragments;
+        int    payload_len;
+        unsigned int nhoff;
+
+        fq_kill(fq);
+
+        BUG_TRAP(head != NULL);
+        BUG_TRAP(FRAG6_CB(head)->offset == 0);
+
+        /* Unfragmented part is taken from the first segment. */
+        payload_len = (head->data - head->nh.raw) - sizeof(struct ipv6hdr) + fq->len - sizeof(struct frag_hdr);
+        if (payload_len > IPV6_MAXPLEN)
+                goto out_oversize;
+
+        /* Head of list must not be cloned. */
+        if (skb_cloned(head) && pskb_expand_head(head, 0, 0, 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_shinfo(head)->frag_list) {
+                struct sk_buff *clone;
+                int i, plen = 0;
+
+                if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
+                        goto out_oom;
+                clone->next = head->next;
+                head->next = clone;
+                skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
+                skb_shinfo(head)->frag_list = NULL;
+                for (i=0; i<skb_shinfo(head)->nr_frags; i++)
+                        plen += skb_shinfo(head)->frags[i].size;
+                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;
+                atomic_add(clone->truesize, &ip6_frag_mem);
+        }
+
+        /* We have to remove fragment header from datagram and to relocate
+         * header in order to calculate ICV correctly. */
+        nhoff = fq->nhoffset;
+        head->nh.raw[nhoff] = head->h.raw[0];
+        memmove(head->head + sizeof(struct frag_hdr), head->head, 
+                (head->data - head->head) - sizeof(struct frag_hdr));
+        head->mac.raw += sizeof(struct frag_hdr);
+        head->nh.raw += sizeof(struct frag_hdr);
+
+        skb_shinfo(head)->frag_list = head->next;
+        head->h.raw = head->data;
+        skb_push(head, head->data - head->nh.raw);
+        atomic_sub(head->truesize, &ip6_frag_mem);
+
+        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_HW)
+                        head->csum = csum_add(head->csum, fp->csum);
+                head->truesize += fp->truesize;
+                atomic_sub(fp->truesize, &ip6_frag_mem);
+        }
+
+        head->next = NULL;
+        head->dev = dev;
+        head->stamp = fq->stamp;
+        head->nh.ipv6h->payload_len = htons(payload_len);
+
+        *skb_in = head;
+
+        /* Yes, and fold redundant checksum back. 8) */
+        if (head->ip_summed == CHECKSUM_HW)
+                head->csum = csum_partial(head->nh.raw, head->h.raw-head->nh.raw, head->csum);
+
+        IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS);
+        fq->fragments = NULL;
+        *nhoffp = nhoff;
+        return 1;
+
+out_oversize:
+        if (net_ratelimit())
+                printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
+        goto out_fail;
+out_oom:
+        if (net_ratelimit())
+                printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
+out_fail:
+        IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
+        return -1;
+}
+
+static int ipv6_frag_rcv(struct sk_buff **skbp, unsigned int *nhoffp)
+{
+        struct sk_buff *skb = *skbp; 
+        struct net_device *dev = skb->dev;
+        struct frag_hdr *fhdr;
+        struct frag_queue *fq;
+        struct ipv6hdr *hdr;
+
+        hdr = skb->nh.ipv6h;
+
+        IP6_INC_STATS_BH(IPSTATS_MIB_REASMREQDS);
+
+        /* Jumbo payload inhibits frag. header */
+        if (hdr->payload_len==0) {
+                IP6_INC_STATS(IPSTATS_MIB_INHDRERRORS);
+                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
+                return -1;
+        }
+        if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+sizeof(struct frag_hdr))) {
+                IP6_INC_STATS(IPSTATS_MIB_INHDRERRORS);
+                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
+                return -1;
+        }
+
+        hdr = skb->nh.ipv6h;
+        fhdr = (struct frag_hdr *)skb->h.raw;
+
+        if (!(fhdr->frag_off & htons(0xFFF9))) {
+                /* It is not a fragmented frame */
+                skb->h.raw += sizeof(struct frag_hdr);
+                IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS);
+
+                *nhoffp = (u8*)fhdr - skb->nh.raw;
+                return 1;
+        }
+
+        if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh)
+                ip6_evictor();
+
+        if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr)) != NULL) {
+                int ret = -1;
+
+                spin_lock(&fq->lock);
+
+                ip6_frag_queue(fq, skb, fhdr, *nhoffp);
+
+                if (fq->last_in == (FIRST_IN|LAST_IN) &&
+                    fq->meat == fq->len)
+                        ret = ip6_frag_reasm(fq, skbp, nhoffp, dev);
+
+                spin_unlock(&fq->lock);
+                fq_put(fq, NULL);
+                return ret;
+        }
+
+        IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
+        kfree_skb(skb);
+        return -1;
+}
+
+static struct inet6_protocol frag_protocol =
+{
+        .handler        =       ipv6_frag_rcv,
+        .flags          =       INET6_PROTO_NOPOLICY,
+};
+
+void __init ipv6_frag_init(void)
+{
+        if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0)
+                printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n");
+
+        ip6_frag_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
+                                   (jiffies ^ (jiffies >> 6)));
+
+        init_timer(&ip6_frag_secret_timer);
+        ip6_frag_secret_timer.function = ip6_frag_secret_rebuild;
+        ip6_frag_secret_timer.expires = jiffies + sysctl_ip6frag_secret_interval;
+        add_timer(&ip6_frag_secret_timer);
+}