--- /dev/null
+/*
+ * IPv6 fragment reassembly for connection tracking
+ *
+ * Copyright (C)2004 USAGI/WIDE Project
+ *
+ * Author:
+ * Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
+ *
+ * Based on: net/ipv6/reassembly.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.
+ */
+
+#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>
+#include <linux/sysctl.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv6.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(format, args...)
+#endif
+
+#define NF_CT_FRAG6_HIGH_THRESH 262144 /* == 256*1024 */
+#define NF_CT_FRAG6_LOW_THRESH 196608 /* == 192*1024 */
+#define NF_CT_FRAG6_TIMEOUT IPV6_FRAG_TIMEOUT
+
+unsigned int nf_ct_frag6_high_thresh = 256*1024;
+unsigned int nf_ct_frag6_low_thresh = 192*1024;
+unsigned long nf_ct_frag6_timeout = IPV6_FRAG_TIMEOUT;
+
+struct nf_ct_frag6_skb_cb
+{
+ struct inet6_skb_parm h;
+ int offset;
+ struct sk_buff *orig;
+};
+
+#define NFCT_FRAG6_CB(skb) ((struct nf_ct_frag6_skb_cb*)((skb)->cb))
+
+struct nf_ct_frag6_queue
+{
+ struct hlist_node list;
+ 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;
+ 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;
+};
+
+/* Hash table. */
+
+#define FRAG6Q_HASHSZ 64
+
+static struct hlist_head nf_ct_frag6_hash[FRAG6Q_HASHSZ];
+static DEFINE_RWLOCK(nf_ct_frag6_lock);
+static u32 nf_ct_frag6_hash_rnd;
+static LIST_HEAD(nf_ct_frag6_lru_list);
+int nf_ct_frag6_nqueues = 0;
+
+static __inline__ void __fq_unlink(struct nf_ct_frag6_queue *fq)
+{
+ hlist_del(&fq->list);
+ list_del(&fq->lru_list);
+ nf_ct_frag6_nqueues--;
+}
+
+static __inline__ void fq_unlink(struct nf_ct_frag6_queue *fq)
+{
+ write_lock(&nf_ct_frag6_lock);
+ __fq_unlink(fq);
+ write_unlock(&nf_ct_frag6_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 += nf_ct_frag6_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 & (FRAG6Q_HASHSZ - 1);
+}
+
+static struct timer_list nf_ct_frag6_secret_timer;
+int nf_ct_frag6_secret_interval = 10 * 60 * HZ;
+
+static void nf_ct_frag6_secret_rebuild(unsigned long dummy)
+{
+ unsigned long now = jiffies;
+ int i;
+
+ write_lock(&nf_ct_frag6_lock);
+ get_random_bytes(&nf_ct_frag6_hash_rnd, sizeof(u32));
+ for (i = 0; i < FRAG6Q_HASHSZ; i++) {
+ struct nf_ct_frag6_queue *q;
+ struct hlist_node *p, *n;
+
+ hlist_for_each_entry_safe(q, p, n, &nf_ct_frag6_hash[i], list) {
+ unsigned int hval = ip6qhashfn(q->id,
+ &q->saddr,
+ &q->daddr);
+ if (hval != i) {
+ hlist_del(&q->list);
+ /* Relink to new hash chain. */
+ hlist_add_head(&q->list,
+ &nf_ct_frag6_hash[hval]);
+ }
+ }
+ }
+ write_unlock(&nf_ct_frag6_lock);
+
+ mod_timer(&nf_ct_frag6_secret_timer, now + nf_ct_frag6_secret_interval);
+}
+
+atomic_t nf_ct_frag6_mem = ATOMIC_INIT(0);
+
+/* Memory Tracking Functions. */
+static inline void frag_kfree_skb(struct sk_buff *skb, unsigned int *work)
+{
+ if (work)
+ *work -= skb->truesize;
+ atomic_sub(skb->truesize, &nf_ct_frag6_mem);
+ if (NFCT_FRAG6_CB(skb)->orig)
+ kfree_skb(NFCT_FRAG6_CB(skb)->orig);
+
+ kfree_skb(skb);
+}
+
+static inline void frag_free_queue(struct nf_ct_frag6_queue *fq,
+ unsigned int *work)
+{
+ if (work)
+ *work -= sizeof(struct nf_ct_frag6_queue);
+ atomic_sub(sizeof(struct nf_ct_frag6_queue), &nf_ct_frag6_mem);
+ kfree(fq);
+}
+
+static inline struct nf_ct_frag6_queue *frag_alloc_queue(void)
+{
+ struct nf_ct_frag6_queue *fq = kmalloc(sizeof(struct nf_ct_frag6_queue), GFP_ATOMIC);
+
+ if (!fq)
+ return NULL;
+ atomic_add(sizeof(struct nf_ct_frag6_queue), &nf_ct_frag6_mem);
+ return fq;
+}
+
+/* Destruction primitives. */
+
+/* Complete destruction of fq. */
+static void nf_ct_frag6_destroy(struct nf_ct_frag6_queue *fq,
+ unsigned 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 nf_ct_frag6_queue *fq, unsigned int *work)
+{
+ if (atomic_dec_and_test(&fq->refcnt))
+ nf_ct_frag6_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 nf_ct_frag6_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 nf_ct_frag6_evictor(void)
+{
+ struct nf_ct_frag6_queue *fq;
+ struct list_head *tmp;
+ unsigned int work;
+
+ work = atomic_read(&nf_ct_frag6_mem);
+ if (work <= nf_ct_frag6_low_thresh)
+ return;
+
+ work -= nf_ct_frag6_low_thresh;
+ while (work > 0) {
+ read_lock(&nf_ct_frag6_lock);
+ if (list_empty(&nf_ct_frag6_lru_list)) {
+ read_unlock(&nf_ct_frag6_lock);
+ return;
+ }
+ tmp = nf_ct_frag6_lru_list.next;
+ BUG_ON(tmp == NULL);
+ fq = list_entry(tmp, struct nf_ct_frag6_queue, lru_list);
+ atomic_inc(&fq->refcnt);
+ read_unlock(&nf_ct_frag6_lock);
+
+ spin_lock(&fq->lock);
+ if (!(fq->last_in&COMPLETE))
+ fq_kill(fq);
+ spin_unlock(&fq->lock);
+
+ fq_put(fq, &work);
+ }
+}
+
+static void nf_ct_frag6_expire(unsigned long data)
+{
+ struct nf_ct_frag6_queue *fq = (struct nf_ct_frag6_queue *) data;
+
+ spin_lock(&fq->lock);
+
+ if (fq->last_in & COMPLETE)
+ goto out;
+
+ fq_kill(fq);
+
+out:
+ spin_unlock(&fq->lock);
+ fq_put(fq, NULL);
+}
+
+/* Creation primitives. */
+
+static struct nf_ct_frag6_queue *nf_ct_frag6_intern(unsigned int hash,
+ struct nf_ct_frag6_queue *fq_in)
+{
+ struct nf_ct_frag6_queue *fq;
+#ifdef CONFIG_SMP
+ struct hlist_node *n;
+#endif
+
+ write_lock(&nf_ct_frag6_lock);
+#ifdef CONFIG_SMP
+ hlist_for_each_entry(fq, n, &nf_ct_frag6_hash[hash], list) {
+ 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(&nf_ct_frag6_lock);
+ fq_in->last_in |= COMPLETE;
+ fq_put(fq_in, NULL);
+ return fq;
+ }
+ }
+#endif
+ fq = fq_in;
+
+ if (!mod_timer(&fq->timer, jiffies + nf_ct_frag6_timeout))
+ atomic_inc(&fq->refcnt);
+
+ atomic_inc(&fq->refcnt);
+ hlist_add_head(&fq->list, &nf_ct_frag6_hash[hash]);
+ INIT_LIST_HEAD(&fq->lru_list);
+ list_add_tail(&fq->lru_list, &nf_ct_frag6_lru_list);
+ nf_ct_frag6_nqueues++;
+ write_unlock(&nf_ct_frag6_lock);
+ return fq;
+}
+
+
+static struct nf_ct_frag6_queue *
+nf_ct_frag6_create(unsigned int hash, u32 id, struct in6_addr *src, struct in6_addr *dst)
+{
+ struct nf_ct_frag6_queue *fq;
+
+ if ((fq = frag_alloc_queue()) == NULL) {
+ DEBUGP("Can't alloc new queue\n");
+ goto oom;
+ }
+
+ memset(fq, 0, sizeof(struct nf_ct_frag6_queue));
+
+ fq->id = id;
+ ipv6_addr_copy(&fq->saddr, src);
+ ipv6_addr_copy(&fq->daddr, dst);
+
+ init_timer(&fq->timer);
+ fq->timer.function = nf_ct_frag6_expire;
+ fq->timer.data = (long) fq;
+ spin_lock_init(&fq->lock);
+ atomic_set(&fq->refcnt, 1);
+
+ return nf_ct_frag6_intern(hash, fq);
+
+oom:
+ return NULL;
+}
+
+static __inline__ struct nf_ct_frag6_queue *
+fq_find(u32 id, struct in6_addr *src, struct in6_addr *dst)
+{
+ struct nf_ct_frag6_queue *fq;
+ struct hlist_node *n;
+ unsigned int hash = ip6qhashfn(id, src, dst);
+
+ read_lock(&nf_ct_frag6_lock);
+ hlist_for_each_entry(fq, n, &nf_ct_frag6_hash[hash], list) {
+ if (fq->id == id &&
+ ipv6_addr_equal(src, &fq->saddr) &&
+ ipv6_addr_equal(dst, &fq->daddr)) {
+ atomic_inc(&fq->refcnt);
+ read_unlock(&nf_ct_frag6_lock);
+ return fq;
+ }
+ }
+ read_unlock(&nf_ct_frag6_lock);
+
+ return nf_ct_frag6_create(hash, id, src, dst);
+}
+
+
+static int nf_ct_frag6_queue(struct nf_ct_frag6_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) {
+ DEBUGP("Allready completed\n");
+ 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) {
+ DEBUGP("offset is too large.\n");
+ return -1;
+ }
+
+ 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)) {
+ DEBUGP("already received last fragment\n");
+ 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
+ */
+ DEBUGP("the end of this fragment is not rounded to 8 bytes.\n");
+ return -1;
+ }
+ if (end > fq->len) {
+ /* Some bits beyond end -> corruption. */
+ if (fq->last_in & LAST_IN) {
+ DEBUGP("last packet already reached.\n");
+ 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)) {
+ DEBUGP("queue: message is too short.\n");
+ goto err;
+ }
+ if (end-offset < skb->len) {
+ if (pskb_trim(skb, end - offset)) {
+ DEBUGP("Can't trim\n");
+ 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 (NFCT_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 = (NFCT_FRAG6_CB(prev)->offset + prev->len) - offset;
+
+ if (i > 0) {
+ offset += i;
+ if (end <= offset) {
+ DEBUGP("overlap\n");
+ goto err;
+ }
+ if (!pskb_pull(skb, i)) {
+ DEBUGP("Can't pull\n");
+ 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 && NFCT_FRAG6_CB(next)->offset < end) {
+ /* overlap is 'i' bytes */
+ int i = end - NFCT_FRAG6_CB(next)->offset;
+
+ if (i < next->len) {
+ /* Eat head of the next overlapped fragment
+ * and leave the loop. The next ones cannot overlap.
+ */
+ DEBUGP("Eat head of the overlapped parts.: %d", i);
+ if (!pskb_pull(next, i))
+ goto err;
+
+ /* next fragment */
+ NFCT_FRAG6_CB(next)->offset += i;
+ fq->meat -= i;
+ if (next->ip_summed != CHECKSUM_UNNECESSARY)
+ next->ip_summed = CHECKSUM_NONE;
+ break;
+ } else {
+ struct sk_buff *free_it = next;
+
+ /* Old fragmnet 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);
+ }
+ }
+
+ NFCT_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;
+
+ skb->dev = NULL;
+ skb_get_timestamp(skb, &fq->stamp);
+ fq->meat += skb->len;
+ atomic_add(skb->truesize, &nf_ct_frag6_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(&nf_ct_frag6_lock);
+ list_move_tail(&fq->lru_list, &nf_ct_frag6_lru_list);
+ write_unlock(&nf_ct_frag6_lock);
+ return 0;
+
+err:
+ return -1;
+}
+
+/*
+ * 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 struct sk_buff *
+nf_ct_frag6_reasm(struct nf_ct_frag6_queue *fq, struct net_device *dev)
+{
+ struct sk_buff *fp, *op, *head = fq->fragments;
+ int payload_len;
+
+ fq_kill(fq);
+
+ BUG_TRAP(head != NULL);
+ BUG_TRAP(NFCT_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) {
+ DEBUGP("payload len is too large.\n");
+ goto out_oversize;
+ }
+
+ /* Head of list must not be cloned. */
+ if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) {
+ DEBUGP("skb is cloned but can't expand head");
+ 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) {
+ DEBUGP("Can't alloc skb\n");
+ 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;
+
+ NFCT_FRAG6_CB(clone)->orig = NULL;
+ atomic_add(clone->truesize, &nf_ct_frag6_mem);
+ }
+
+ /* We have to remove fragment header from datagram and to relocate
+ * header in order to calculate ICV correctly. */
+ head->nh.raw[fq->nhoffset] = 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, &nf_ct_frag6_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, &nf_ct_frag6_mem);
+ }
+
+ head->next = NULL;
+ head->dev = dev;
+ skb_set_timestamp(head, &fq->stamp);
+ head->nh.ipv6h->payload_len = htons(payload_len);
+
+ /* 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);
+
+ fq->fragments = NULL;
+
+ /* all original skbs are linked into the NFCT_FRAG6_CB(head).orig */
+ fp = skb_shinfo(head)->frag_list;
+ if (NFCT_FRAG6_CB(fp)->orig == NULL)
+ /* at above code, head skb is divided into two skbs. */
+ fp = fp->next;
+
+ op = NFCT_FRAG6_CB(head)->orig;
+ for (; fp; fp = fp->next) {
+ struct sk_buff *orig = NFCT_FRAG6_CB(fp)->orig;
+
+ op->next = orig;
+ op = orig;
+ NFCT_FRAG6_CB(fp)->orig = NULL;
+ }
+
+ return head;
+
+out_oversize:
+ if (net_ratelimit())
+ printk(KERN_DEBUG "nf_ct_frag6_reasm: payload len = %d\n", payload_len);
+ goto out_fail;
+out_oom:
+ if (net_ratelimit())
+ printk(KERN_DEBUG "nf_ct_frag6_reasm: no memory for reassembly\n");
+out_fail:
+ return NULL;
+}
+
+/*
+ * find the header just before Fragment Header.
+ *
+ * if success return 0 and set ...
+ * (*prevhdrp): the value of "Next Header Field" in the header
+ * just before Fragment Header.
+ * (*prevhoff): the offset of "Next Header Field" in the header
+ * just before Fragment Header.
+ * (*fhoff) : the offset of Fragment Header.
+ *
+ * Based on ipv6_skip_hdr() in net/ipv6/exthdr.c
+ *
+ */
+static int
+find_prev_fhdr(struct sk_buff *skb, u8 *prevhdrp, int *prevhoff, int *fhoff)
+{
+ u8 nexthdr = skb->nh.ipv6h->nexthdr;
+ u8 prev_nhoff = (u8 *)&skb->nh.ipv6h->nexthdr - skb->data;
+ int start = (u8 *)(skb->nh.ipv6h+1) - skb->data;
+ int len = skb->len - start;
+ u8 prevhdr = NEXTHDR_IPV6;
+
+ while (nexthdr != NEXTHDR_FRAGMENT) {
+ struct ipv6_opt_hdr hdr;
+ int hdrlen;
+
+ if (!ipv6_ext_hdr(nexthdr)) {
+ return -1;
+ }
+ if (len < (int)sizeof(struct ipv6_opt_hdr)) {
+ DEBUGP("too short\n");
+ return -1;
+ }
+ if (nexthdr == NEXTHDR_NONE) {
+ DEBUGP("next header is none\n");
+ return -1;
+ }
+ if (skb_copy_bits(skb, start, &hdr, sizeof(hdr)))
+ BUG();
+ if (nexthdr == NEXTHDR_AUTH)
+ hdrlen = (hdr.hdrlen+2)<<2;
+ else
+ hdrlen = ipv6_optlen(&hdr);
+
+ prevhdr = nexthdr;
+ prev_nhoff = start;
+
+ nexthdr = hdr.nexthdr;
+ len -= hdrlen;
+ start += hdrlen;
+ }
+
+ if (len < 0)
+ return -1;
+
+ *prevhdrp = prevhdr;
+ *prevhoff = prev_nhoff;
+ *fhoff = start;
+
+ return 0;
+}
+
+struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb)
+{
+ struct sk_buff *clone;
+ struct net_device *dev = skb->dev;
+ struct frag_hdr *fhdr;
+ struct nf_ct_frag6_queue *fq;
+ struct ipv6hdr *hdr;
+ int fhoff, nhoff;
+ u8 prevhdr;
+ struct sk_buff *ret_skb = NULL;
+
+ /* Jumbo payload inhibits frag. header */
+ if (skb->nh.ipv6h->payload_len == 0) {
+ DEBUGP("payload len = 0\n");
+ return skb;
+ }
+
+ if (find_prev_fhdr(skb, &prevhdr, &nhoff, &fhoff) < 0)
+ return skb;
+
+ clone = skb_clone(skb, GFP_ATOMIC);
+ if (clone == NULL) {
+ DEBUGP("Can't clone skb\n");
+ return skb;
+ }
+
+ NFCT_FRAG6_CB(clone)->orig = skb;
+
+ if (!pskb_may_pull(clone, fhoff + sizeof(*fhdr))) {
+ DEBUGP("message is too short.\n");
+ goto ret_orig;
+ }
+
+ clone->h.raw = clone->data + fhoff;
+ hdr = clone->nh.ipv6h;
+ fhdr = (struct frag_hdr *)clone->h.raw;
+
+ if (!(fhdr->frag_off & htons(0xFFF9))) {
+ DEBUGP("Invalid fragment offset\n");
+ /* It is not a fragmented frame */
+ goto ret_orig;
+ }
+
+ if (atomic_read(&nf_ct_frag6_mem) > nf_ct_frag6_high_thresh)
+ nf_ct_frag6_evictor();
+
+ fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr);
+ if (fq == NULL) {
+ DEBUGP("Can't find and can't create new queue\n");
+ goto ret_orig;
+ }
+
+ spin_lock(&fq->lock);
+
+ if (nf_ct_frag6_queue(fq, clone, fhdr, nhoff) < 0) {
+ spin_unlock(&fq->lock);
+ DEBUGP("Can't insert skb to queue\n");
+ fq_put(fq, NULL);
+ goto ret_orig;
+ }
+
+ if (fq->last_in == (FIRST_IN|LAST_IN) && fq->meat == fq->len) {
+ ret_skb = nf_ct_frag6_reasm(fq, dev);
+ if (ret_skb == NULL)
+ DEBUGP("Can't reassemble fragmented packets\n");
+ }
+ spin_unlock(&fq->lock);
+
+ fq_put(fq, NULL);
+ return ret_skb;
+
+ret_orig:
+ kfree_skb(clone);
+ return skb;
+}
+
+void nf_ct_frag6_output(unsigned int hooknum, struct sk_buff *skb,
+ struct net_device *in, struct net_device *out,
+ int (*okfn)(struct sk_buff *))
+{
+ struct sk_buff *s, *s2;
+
+ for (s = NFCT_FRAG6_CB(skb)->orig; s;) {
+ nf_conntrack_put_reasm(s->nfct_reasm);
+ nf_conntrack_get_reasm(skb);
+ s->nfct_reasm = skb;
+
+ s2 = s->next;
+ NF_HOOK_THRESH(PF_INET6, hooknum, s, in, out, okfn,
+ NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
+ s = s2;
+ }
+ nf_conntrack_put_reasm(skb);
+}
+
+int nf_ct_frag6_kfree_frags(struct sk_buff *skb)
+{
+ struct sk_buff *s, *s2;
+
+ for (s = NFCT_FRAG6_CB(skb)->orig; s; s = s2) {
+
+ s2 = s->next;
+ kfree_skb(s);
+ }
+
+ kfree_skb(skb);
+
+ return 0;
+}
+
+int nf_ct_frag6_init(void)
+{
+ nf_ct_frag6_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
+ (jiffies ^ (jiffies >> 6)));
+
+ init_timer(&nf_ct_frag6_secret_timer);
+ nf_ct_frag6_secret_timer.function = nf_ct_frag6_secret_rebuild;
+ nf_ct_frag6_secret_timer.expires = jiffies
+ + nf_ct_frag6_secret_interval;
+ add_timer(&nf_ct_frag6_secret_timer);
+
+ return 0;
+}
+
+void nf_ct_frag6_cleanup(void)
+{
+ del_timer(&nf_ct_frag6_secret_timer);
+ nf_ct_frag6_low_thresh = 0;
+ nf_ct_frag6_evictor();
+}
git://git.onelab.eu / linux-2.6.git / blobdiff