| /* |
| * 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. |
| * |
| * Version: $Id: ip_fragment.c,v 1.59 2002/01/12 07:54:56 davem Exp $ |
| * |
| * Authors: Fred N. van Kempen <waltje@uWalt.NL.Mugnet.ORG> |
| * Alan Cox <Alan.Cox@linux.org> |
| * |
| * 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. |
| */ |
| |
| #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 <net/sock.h> |
| #include <net/ip.h> |
| #include <net/icmp.h> |
| #include <net/checksum.h> |
| #include <net/inetpeer.h> |
| #include <linux/tcp.h> |
| #include <linux/udp.h> |
| #include <linux/inet.h> |
| #include <linux/netfilter_ipv4.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 |
| */ |
| |
| /* Fragment cache limits. We will commit 256K at one time. Should we |
| * cross that limit we will prune down to 192K. This should cope with |
| * even the most extreme cases without allowing an attacker to measurably |
| * harm machine performance. |
| */ |
| int sysctl_ipfrag_high_thresh __read_mostly = 256*1024; |
| int sysctl_ipfrag_low_thresh __read_mostly = 192*1024; |
| |
| int sysctl_ipfrag_max_dist __read_mostly = 64; |
| |
| /* Important NOTE! Fragment queue must be destroyed before MSL expires. |
| * RFC791 is wrong proposing to prolongate timer each fragment arrival by TTL. |
| */ |
| int sysctl_ipfrag_time __read_mostly = IP_FRAG_TIME; |
| |
| struct ipfrag_skb_cb |
| { |
| struct inet_skb_parm h; |
| int offset; |
| }; |
| |
| #define FRAG_CB(skb) ((struct ipfrag_skb_cb*)((skb)->cb)) |
| |
| /* Describe an entry in the "incomplete datagrams" queue. */ |
| struct ipq { |
| struct hlist_node list; |
| struct list_head lru_list; /* lru list member */ |
| u32 user; |
| __be32 saddr; |
| __be32 daddr; |
| __be16 id; |
| u8 protocol; |
| u8 last_in; |
| #define COMPLETE 4 |
| #define FIRST_IN 2 |
| #define LAST_IN 1 |
| |
| struct sk_buff *fragments; /* linked list of received fragments */ |
| int len; /* total length of original datagram */ |
| int meat; |
| spinlock_t lock; |
| atomic_t refcnt; |
| struct timer_list timer; /* when will this queue expire? */ |
| ktime_t stamp; |
| int iif; |
| unsigned int rid; |
| struct inet_peer *peer; |
| }; |
| |
| /* Hash table. */ |
| |
| #define IPQ_HASHSZ 64 |
| |
| /* Per-bucket lock is easy to add now. */ |
| static struct hlist_head ipq_hash[IPQ_HASHSZ]; |
| static DEFINE_RWLOCK(ipfrag_lock); |
| static u32 ipfrag_hash_rnd; |
| static LIST_HEAD(ipq_lru_list); |
| int ip_frag_nqueues = 0; |
| |
| static __inline__ void __ipq_unlink(struct ipq *qp) |
| { |
| hlist_del(&qp->list); |
| list_del(&qp->lru_list); |
| ip_frag_nqueues--; |
| } |
| |
| static __inline__ void ipq_unlink(struct ipq *ipq) |
| { |
| write_lock(&ipfrag_lock); |
| __ipq_unlink(ipq); |
| write_unlock(&ipfrag_lock); |
| } |
| |
| static unsigned int ipqhashfn(__be16 id, __be32 saddr, __be32 daddr, u8 prot) |
| { |
| return jhash_3words((__force u32)id << 16 | prot, |
| (__force u32)saddr, (__force u32)daddr, |
| ipfrag_hash_rnd) & (IPQ_HASHSZ - 1); |
| } |
| |
| static struct timer_list ipfrag_secret_timer; |
| int sysctl_ipfrag_secret_interval __read_mostly = 10 * 60 * HZ; |
| |
| static void ipfrag_secret_rebuild(unsigned long dummy) |
| { |
| unsigned long now = jiffies; |
| int i; |
| |
| write_lock(&ipfrag_lock); |
| get_random_bytes(&ipfrag_hash_rnd, sizeof(u32)); |
| for (i = 0; i < IPQ_HASHSZ; i++) { |
| struct ipq *q; |
| struct hlist_node *p, *n; |
| |
| hlist_for_each_entry_safe(q, p, n, &ipq_hash[i], list) { |
| unsigned int hval = ipqhashfn(q->id, q->saddr, |
| q->daddr, q->protocol); |
| |
| if (hval != i) { |
| hlist_del(&q->list); |
| |
| /* Relink to new hash chain. */ |
| hlist_add_head(&q->list, &ipq_hash[hval]); |
| } |
| } |
| } |
| write_unlock(&ipfrag_lock); |
| |
| mod_timer(&ipfrag_secret_timer, now + sysctl_ipfrag_secret_interval); |
| } |
| |
| atomic_t ip_frag_mem = ATOMIC_INIT(0); /* Memory used for fragments */ |
| |
| /* Memory Tracking Functions. */ |
| static __inline__ void frag_kfree_skb(struct sk_buff *skb, int *work) |
| { |
| if (work) |
| *work -= skb->truesize; |
| atomic_sub(skb->truesize, &ip_frag_mem); |
| kfree_skb(skb); |
| } |
| |
| static __inline__ void frag_free_queue(struct ipq *qp, int *work) |
| { |
| if (work) |
| *work -= sizeof(struct ipq); |
| atomic_sub(sizeof(struct ipq), &ip_frag_mem); |
| kfree(qp); |
| } |
| |
| static __inline__ struct ipq *frag_alloc_queue(void) |
| { |
| struct ipq *qp = kmalloc(sizeof(struct ipq), GFP_ATOMIC); |
| |
| if(!qp) |
| return NULL; |
| atomic_add(sizeof(struct ipq), &ip_frag_mem); |
| return qp; |
| } |
| |
| |
| /* Destruction primitives. */ |
| |
| /* Complete destruction of ipq. */ |
| static void ip_frag_destroy(struct ipq *qp, int *work) |
| { |
| struct sk_buff *fp; |
| |
| BUG_TRAP(qp->last_in&COMPLETE); |
| BUG_TRAP(del_timer(&qp->timer) == 0); |
| |
| if (qp->peer) |
| inet_putpeer(qp->peer); |
| |
| /* Release all fragment data. */ |
| fp = qp->fragments; |
| while (fp) { |
| struct sk_buff *xp = fp->next; |
| |
| frag_kfree_skb(fp, work); |
| fp = xp; |
| } |
| |
| /* Finally, release the queue descriptor itself. */ |
| frag_free_queue(qp, work); |
| } |
| |
| static __inline__ void ipq_put(struct ipq *ipq, int *work) |
| { |
| if (atomic_dec_and_test(&ipq->refcnt)) |
| ip_frag_destroy(ipq, work); |
| } |
| |
| /* Kill ipq entry. It is not destroyed immediately, |
| * because caller (and someone more) holds reference count. |
| */ |
| static void ipq_kill(struct ipq *ipq) |
| { |
| if (del_timer(&ipq->timer)) |
| atomic_dec(&ipq->refcnt); |
| |
| if (!(ipq->last_in & COMPLETE)) { |
| ipq_unlink(ipq); |
| atomic_dec(&ipq->refcnt); |
| ipq->last_in |= COMPLETE; |
| } |
| } |
| |
| /* Memory limiting on fragments. Evictor trashes the oldest |
| * fragment queue until we are back under the threshold. |
| */ |
| static void ip_evictor(void) |
| { |
| struct ipq *qp; |
| struct list_head *tmp; |
| int work; |
| |
| work = atomic_read(&ip_frag_mem) - sysctl_ipfrag_low_thresh; |
| if (work <= 0) |
| return; |
| |
| while (work > 0) { |
| read_lock(&ipfrag_lock); |
| if (list_empty(&ipq_lru_list)) { |
| read_unlock(&ipfrag_lock); |
| return; |
| } |
| tmp = ipq_lru_list.next; |
| qp = list_entry(tmp, struct ipq, lru_list); |
| atomic_inc(&qp->refcnt); |
| read_unlock(&ipfrag_lock); |
| |
| spin_lock(&qp->lock); |
| if (!(qp->last_in&COMPLETE)) |
| ipq_kill(qp); |
| spin_unlock(&qp->lock); |
| |
| ipq_put(qp, &work); |
| IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); |
| } |
| } |
| |
| /* |
| * Oops, a fragment queue timed out. Kill it and send an ICMP reply. |
| */ |
| static void ip_expire(unsigned long arg) |
| { |
| struct ipq *qp = (struct ipq *) arg; |
| |
| spin_lock(&qp->lock); |
| |
| if (qp->last_in & COMPLETE) |
| goto out; |
| |
| ipq_kill(qp); |
| |
| IP_INC_STATS_BH(IPSTATS_MIB_REASMTIMEOUT); |
| IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); |
| |
| if ((qp->last_in&FIRST_IN) && qp->fragments != NULL) { |
| struct sk_buff *head = qp->fragments; |
| /* Send an ICMP "Fragment Reassembly Timeout" message. */ |
| if ((head->dev = dev_get_by_index(qp->iif)) != NULL) { |
| icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0); |
| dev_put(head->dev); |
| } |
| } |
| out: |
| spin_unlock(&qp->lock); |
| ipq_put(qp, NULL); |
| } |
| |
| /* Creation primitives. */ |
| |
| static struct ipq *ip_frag_intern(struct ipq *qp_in) |
| { |
| struct ipq *qp; |
| #ifdef CONFIG_SMP |
| struct hlist_node *n; |
| #endif |
| unsigned int hash; |
| |
| write_lock(&ipfrag_lock); |
| hash = ipqhashfn(qp_in->id, qp_in->saddr, qp_in->daddr, |
| qp_in->protocol); |
| #ifdef CONFIG_SMP |
| /* With SMP race we have to recheck hash table, because |
| * such entry could be created on other cpu, while we |
| * promoted read lock to write lock. |
| */ |
| hlist_for_each_entry(qp, n, &ipq_hash[hash], list) { |
| if(qp->id == qp_in->id && |
| qp->saddr == qp_in->saddr && |
| qp->daddr == qp_in->daddr && |
| qp->protocol == qp_in->protocol && |
| qp->user == qp_in->user) { |
| atomic_inc(&qp->refcnt); |
| write_unlock(&ipfrag_lock); |
| qp_in->last_in |= COMPLETE; |
| ipq_put(qp_in, NULL); |
| return qp; |
| } |
| } |
| #endif |
| qp = qp_in; |
| |
| if (!mod_timer(&qp->timer, jiffies + sysctl_ipfrag_time)) |
| atomic_inc(&qp->refcnt); |
| |
| atomic_inc(&qp->refcnt); |
| hlist_add_head(&qp->list, &ipq_hash[hash]); |
| INIT_LIST_HEAD(&qp->lru_list); |
| list_add_tail(&qp->lru_list, &ipq_lru_list); |
| ip_frag_nqueues++; |
| write_unlock(&ipfrag_lock); |
| return qp; |
| } |
| |
| /* Add an entry to the 'ipq' queue for a newly received IP datagram. */ |
| static struct ipq *ip_frag_create(struct iphdr *iph, u32 user) |
| { |
| struct ipq *qp; |
| |
| if ((qp = frag_alloc_queue()) == NULL) |
| goto out_nomem; |
| |
| qp->protocol = iph->protocol; |
| qp->last_in = 0; |
| qp->id = iph->id; |
| qp->saddr = iph->saddr; |
| qp->daddr = iph->daddr; |
| qp->user = user; |
| qp->len = 0; |
| qp->meat = 0; |
| qp->fragments = NULL; |
| qp->iif = 0; |
| qp->peer = sysctl_ipfrag_max_dist ? inet_getpeer(iph->saddr, 1) : NULL; |
| |
| /* Initialize a timer for this entry. */ |
| init_timer(&qp->timer); |
| qp->timer.data = (unsigned long) qp; /* pointer to queue */ |
| qp->timer.function = ip_expire; /* expire function */ |
| spin_lock_init(&qp->lock); |
| atomic_set(&qp->refcnt, 1); |
| |
| return ip_frag_intern(qp); |
| |
| out_nomem: |
| LIMIT_NETDEBUG(KERN_ERR "ip_frag_create: no memory left !\n"); |
| return NULL; |
| } |
| |
| /* Find the correct entry in the "incomplete datagrams" queue for |
| * this IP datagram, and create new one, if nothing is found. |
| */ |
| static inline struct ipq *ip_find(struct iphdr *iph, u32 user) |
| { |
| __be16 id = iph->id; |
| __be32 saddr = iph->saddr; |
| __be32 daddr = iph->daddr; |
| __u8 protocol = iph->protocol; |
| unsigned int hash; |
| struct ipq *qp; |
| struct hlist_node *n; |
| |
| read_lock(&ipfrag_lock); |
| hash = ipqhashfn(id, saddr, daddr, protocol); |
| hlist_for_each_entry(qp, n, &ipq_hash[hash], list) { |
| if(qp->id == id && |
| qp->saddr == saddr && |
| qp->daddr == daddr && |
| qp->protocol == protocol && |
| qp->user == user) { |
| atomic_inc(&qp->refcnt); |
| read_unlock(&ipfrag_lock); |
| return qp; |
| } |
| } |
| read_unlock(&ipfrag_lock); |
| |
| return ip_frag_create(iph, user); |
| } |
| |
| /* Is the fragment too far ahead to be part of ipq? */ |
| static inline int ip_frag_too_far(struct ipq *qp) |
| { |
| struct inet_peer *peer = qp->peer; |
| unsigned int max = sysctl_ipfrag_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->fragments && (end - start) > max; |
| |
| if (rc) { |
| IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); |
| } |
| |
| return rc; |
| } |
| |
| static int ip_frag_reinit(struct ipq *qp) |
| { |
| struct sk_buff *fp; |
| |
| if (!mod_timer(&qp->timer, jiffies + sysctl_ipfrag_time)) { |
| atomic_inc(&qp->refcnt); |
| return -ETIMEDOUT; |
| } |
| |
| fp = qp->fragments; |
| do { |
| struct sk_buff *xp = fp->next; |
| frag_kfree_skb(fp, NULL); |
| fp = xp; |
| } while (fp); |
| |
| qp->last_in = 0; |
| qp->len = 0; |
| qp->meat = 0; |
| qp->fragments = NULL; |
| qp->iif = 0; |
| |
| return 0; |
| } |
| |
| /* Add new segment to existing queue. */ |
| static void ip_frag_queue(struct ipq *qp, struct sk_buff *skb) |
| { |
| struct sk_buff *prev, *next; |
| int flags, offset; |
| int ihl, end; |
| |
| if (qp->last_in & COMPLETE) |
| goto err; |
| |
| if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) && |
| unlikely(ip_frag_too_far(qp)) && unlikely(ip_frag_reinit(qp))) { |
| ipq_kill(qp); |
| goto err; |
| } |
| |
| offset = ntohs(skb->nh.iph->frag_off); |
| flags = offset & ~IP_OFFSET; |
| offset &= IP_OFFSET; |
| offset <<= 3; /* offset is in 8-byte chunks */ |
| ihl = skb->nh.iph->ihl * 4; |
| |
| /* Determine the position of this fragment. */ |
| end = offset + skb->len - ihl; |
| |
| /* 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 corrrupted. |
| */ |
| if (end < qp->len || |
| ((qp->last_in & LAST_IN) && end != qp->len)) |
| goto err; |
| qp->last_in |= LAST_IN; |
| qp->len = end; |
| } else { |
| if (end&7) { |
| end &= ~7; |
| if (skb->ip_summed != CHECKSUM_UNNECESSARY) |
| skb->ip_summed = CHECKSUM_NONE; |
| } |
| if (end > qp->len) { |
| /* Some bits beyond end -> corruption. */ |
| if (qp->last_in & LAST_IN) |
| goto err; |
| qp->len = end; |
| } |
| } |
| if (end == offset) |
| goto err; |
| |
| if (pskb_pull(skb, ihl) == NULL) |
| 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 = qp->fragments; next != NULL; next = next->next) { |
| if (FRAG_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 = (FRAG_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; |
| } |
| } |
| |
| while (next && FRAG_CB(next)->offset < end) { |
| int i = end - FRAG_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; |
| FRAG_CB(next)->offset += i; |
| qp->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 |
| qp->fragments = next; |
| |
| qp->meat -= free_it->len; |
| frag_kfree_skb(free_it, NULL); |
| } |
| } |
| |
| FRAG_CB(skb)->offset = offset; |
| |
| /* Insert this fragment in the chain of fragments. */ |
| skb->next = next; |
| if (prev) |
| prev->next = skb; |
| else |
| qp->fragments = skb; |
| |
| if (skb->dev) |
| qp->iif = skb->dev->ifindex; |
| skb->dev = NULL; |
| qp->stamp = skb->tstamp; |
| qp->meat += skb->len; |
| atomic_add(skb->truesize, &ip_frag_mem); |
| if (offset == 0) |
| qp->last_in |= FIRST_IN; |
| |
| write_lock(&ipfrag_lock); |
| list_move_tail(&qp->lru_list, &ipq_lru_list); |
| write_unlock(&ipfrag_lock); |
| |
| return; |
| |
| err: |
| kfree_skb(skb); |
| } |
| |
| |
| /* Build a new IP datagram from all its fragments. */ |
| |
| static struct sk_buff *ip_frag_reasm(struct ipq *qp, struct net_device *dev) |
| { |
| struct iphdr *iph; |
| struct sk_buff *fp, *head = qp->fragments; |
| int len; |
| int ihlen; |
| |
| ipq_kill(qp); |
| |
| BUG_TRAP(head != NULL); |
| BUG_TRAP(FRAG_CB(head)->offset == 0); |
| |
| /* Allocate a new buffer for the datagram. */ |
| ihlen = head->nh.iph->ihl*4; |
| len = ihlen + qp->len; |
| |
| if(len > 65535) |
| goto out_oversize; |
| |
| /* Head of list must not be cloned. */ |
| if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) |
| goto out_nomem; |
| |
| /* 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_nomem; |
| 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, &ip_frag_mem); |
| } |
| |
| skb_shinfo(head)->frag_list = head->next; |
| skb_push(head, head->data - head->nh.raw); |
| atomic_sub(head->truesize, &ip_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, &ip_frag_mem); |
| } |
| |
| head->next = NULL; |
| head->dev = dev; |
| head->tstamp = qp->stamp; |
| |
| iph = head->nh.iph; |
| iph->frag_off = 0; |
| iph->tot_len = htons(len); |
| IP_INC_STATS_BH(IPSTATS_MIB_REASMOKS); |
| qp->fragments = NULL; |
| return head; |
| |
| out_nomem: |
| LIMIT_NETDEBUG(KERN_ERR "IP: queue_glue: no memory for gluing " |
| "queue %p\n", qp); |
| goto out_fail; |
| out_oversize: |
| if (net_ratelimit()) |
| printk(KERN_INFO |
| "Oversized IP packet from %d.%d.%d.%d.\n", |
| NIPQUAD(qp->saddr)); |
| out_fail: |
| IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); |
| return NULL; |
| } |
| |
| /* Process an incoming IP datagram fragment. */ |
| struct sk_buff *ip_defrag(struct sk_buff *skb, u32 user) |
| { |
| struct iphdr *iph = skb->nh.iph; |
| struct ipq *qp; |
| struct net_device *dev; |
| |
| IP_INC_STATS_BH(IPSTATS_MIB_REASMREQDS); |
| |
| /* Start by cleaning up the memory. */ |
| if (atomic_read(&ip_frag_mem) > sysctl_ipfrag_high_thresh) |
| ip_evictor(); |
| |
| dev = skb->dev; |
| |
| /* Lookup (or create) queue header */ |
| if ((qp = ip_find(iph, user)) != NULL) { |
| struct sk_buff *ret = NULL; |
| |
| spin_lock(&qp->lock); |
| |
| ip_frag_queue(qp, skb); |
| |
| if (qp->last_in == (FIRST_IN|LAST_IN) && |
| qp->meat == qp->len) |
| ret = ip_frag_reasm(qp, dev); |
| |
| spin_unlock(&qp->lock); |
| ipq_put(qp, NULL); |
| return ret; |
| } |
| |
| IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); |
| kfree_skb(skb); |
| return NULL; |
| } |
| |
| void __init ipfrag_init(void) |
| { |
| ipfrag_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^ |
| (jiffies ^ (jiffies >> 6))); |
| |
| init_timer(&ipfrag_secret_timer); |
| ipfrag_secret_timer.function = ipfrag_secret_rebuild; |
| ipfrag_secret_timer.expires = jiffies + sysctl_ipfrag_secret_interval; |
| add_timer(&ipfrag_secret_timer); |
| } |
| |
| EXPORT_SYMBOL(ip_defrag); |