| /* |
| * 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/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/ip6_route.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 __read_mostly = 256*1024; |
| int sysctl_ip6frag_low_thresh __read_mostly = 192*1024; |
| |
| int sysctl_ip6frag_time __read_mostly = 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 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; |
| 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; |
| }; |
| |
| /* Hash table. */ |
| |
| #define IP6Q_HASHSZ 64 |
| |
| static struct hlist_head 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) |
| { |
| hlist_del(&fq->list); |
| 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); |
| } |
| |
| /* |
| * callers should be careful not to use the hash value outside the ipfrag_lock |
| * as doing so could race with ipfrag_hash_rnd being recalculated. |
| */ |
| 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 __read_mostly = 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; |
| struct hlist_node *p, *n; |
| |
| hlist_for_each_entry_safe(q, p, n, &ip6_frag_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, |
| &ip6_frag_hash[hval]); |
| |
| } |
| } |
| } |
| 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 = kzalloc(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(struct inet6_dev *idev) |
| { |
| 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(idev, IPSTATS_MIB_REASMFAILS); |
| } |
| } |
| |
| static void ip6_frag_expire(unsigned long data) |
| { |
| struct frag_queue *fq = (struct frag_queue *) data; |
| struct net_device *dev = NULL; |
| |
| spin_lock(&fq->lock); |
| |
| if (fq->last_in & COMPLETE) |
| goto out; |
| |
| fq_kill(fq); |
| |
| dev = dev_get_by_index(fq->iif); |
| if (!dev) |
| goto out; |
| |
| rcu_read_lock(); |
| IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT); |
| IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS); |
| rcu_read_unlock(); |
| |
| /* Don't send error if the first segment did not arrive. */ |
| if (!(fq->last_in&FIRST_IN) || !fq->fragments) |
| goto out; |
| |
| /* |
| But use as source device on which LAST ARRIVED |
| segment was received. And do not use fq->dev |
| pointer directly, device might already disappeared. |
| */ |
| fq->fragments->dev = dev; |
| icmpv6_send(fq->fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev); |
| out: |
| if (dev) |
| dev_put(dev); |
| spin_unlock(&fq->lock); |
| fq_put(fq, NULL); |
| } |
| |
| /* Creation primitives. */ |
| |
| |
| static struct frag_queue *ip6_frag_intern(struct frag_queue *fq_in) |
| { |
| struct frag_queue *fq; |
| unsigned int hash; |
| #ifdef CONFIG_SMP |
| struct hlist_node *n; |
| #endif |
| |
| write_lock(&ip6_frag_lock); |
| hash = ip6qhashfn(fq_in->id, &fq_in->saddr, &fq_in->daddr); |
| #ifdef CONFIG_SMP |
| hlist_for_each_entry(fq, n, &ip6_frag_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(&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); |
| hlist_add_head(&fq->list, &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(u32 id, struct in6_addr *src, struct in6_addr *dst, |
| struct inet6_dev *idev) |
| { |
| struct frag_queue *fq; |
| |
| if ((fq = frag_alloc_queue()) == NULL) |
| goto oom; |
| |
| 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(fq); |
| |
| oom: |
| IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS); |
| return NULL; |
| } |
| |
| static __inline__ struct frag_queue * |
| fq_find(u32 id, struct in6_addr *src, struct in6_addr *dst, |
| struct inet6_dev *idev) |
| { |
| struct frag_queue *fq; |
| struct hlist_node *n; |
| unsigned int hash; |
| |
| read_lock(&ip6_frag_lock); |
| hash = ip6qhashfn(id, src, dst); |
| hlist_for_each_entry(fq, n, &ip6_frag_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(&ip6_frag_lock); |
| return fq; |
| } |
| } |
| read_unlock(&ip6_frag_lock); |
| |
| return ip6_frag_create(id, src, dst, idev); |
| } |
| |
| |
| 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(ip6_dst_idev(skb->dst), |
| IPSTATS_MIB_INHDRERRORS); |
| icmpv6_param_prob(skb,ICMPV6_HDR_FIELD, (u8*)&fhdr->frag_off - skb->nh.raw); |
| return; |
| } |
| |
| if (skb->ip_summed == CHECKSUM_COMPLETE) |
| 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(ip6_dst_idev(skb->dst), |
| 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 (pskb_trim_rcsum(skb, end - offset)) |
| goto err; |
| |
| /* 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; |
| skb_get_timestamp(skb, &fq->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(ip6_dst_idev(skb->dst), 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, |
| 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_COMPLETE) |
| 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; |
| skb_set_timestamp(head, &fq->stamp); |
| head->nh.ipv6h->payload_len = htons(payload_len); |
| IP6CB(head)->nhoff = nhoff; |
| |
| *skb_in = head; |
| |
| /* Yes, and fold redundant checksum back. 8) */ |
| if (head->ip_summed == CHECKSUM_COMPLETE) |
| head->csum = csum_partial(head->nh.raw, head->h.raw-head->nh.raw, head->csum); |
| |
| rcu_read_lock(); |
| IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMOKS); |
| rcu_read_unlock(); |
| fq->fragments = NULL; |
| 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: |
| rcu_read_lock(); |
| IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS); |
| rcu_read_unlock(); |
| return -1; |
| } |
| |
| static int ipv6_frag_rcv(struct sk_buff **skbp) |
| { |
| 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(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS); |
| |
| /* Jumbo payload inhibits frag. header */ |
| if (hdr->payload_len==0) { |
| IP6_INC_STATS(ip6_dst_idev(skb->dst), 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(ip6_dst_idev(skb->dst), 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(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMOKS); |
| |
| IP6CB(skb)->nhoff = (u8*)fhdr - skb->nh.raw; |
| return 1; |
| } |
| |
| if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh) |
| ip6_evictor(ip6_dst_idev(skb->dst)); |
| |
| if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr, |
| ip6_dst_idev(skb->dst))) != NULL) { |
| int ret = -1; |
| |
| spin_lock(&fq->lock); |
| |
| ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff); |
| |
| if (fq->last_in == (FIRST_IN|LAST_IN) && |
| fq->meat == fq->len) |
| ret = ip6_frag_reasm(fq, skbp, dev); |
| |
| spin_unlock(&fq->lock); |
| fq_put(fq, NULL); |
| return ret; |
| } |
| |
| IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), 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); |
| } |