| // 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"; |
| |
| 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 inet_frag_queue q; |
| |
| u32 user; |
| __be32 saddr; |
| __be32 daddr; |
| __be16 id; |
| u8 protocol; |
| u8 ecn; /* RFC3168 support */ |
| u16 max_df_size; /* largest frag with DF set seen */ |
| int iif; |
| int vif; /* L3 master device index */ |
| 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; |
| |
| int ip_frag_mem(struct net *net) |
| { |
| return sum_frag_mem_limit(&net->ipv4.frags); |
| } |
| |
| static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, |
| struct net_device *dev); |
| |
| struct ip4_create_arg { |
| struct iphdr *iph; |
| u32 user; |
| int vif; |
| }; |
| |
| static unsigned int ipqhashfn(__be16 id, __be32 saddr, __be32 daddr, u8 prot) |
| { |
| net_get_random_once(&ip4_frags.rnd, sizeof(ip4_frags.rnd)); |
| return jhash_3words((__force u32)id << 16 | prot, |
| (__force u32)saddr, (__force u32)daddr, |
| ip4_frags.rnd); |
| } |
| |
| static unsigned int ip4_hashfn(const struct inet_frag_queue *q) |
| { |
| const struct ipq *ipq; |
| |
| ipq = container_of(q, struct ipq, q); |
| return ipqhashfn(ipq->id, ipq->saddr, ipq->daddr, ipq->protocol); |
| } |
| |
| static bool ip4_frag_match(const struct inet_frag_queue *q, const void *a) |
| { |
| const struct ipq *qp; |
| const struct ip4_create_arg *arg = a; |
| |
| qp = container_of(q, struct ipq, q); |
| return qp->id == arg->iph->id && |
| qp->saddr == arg->iph->saddr && |
| qp->daddr == arg->iph->daddr && |
| qp->protocol == arg->iph->protocol && |
| qp->user == arg->user && |
| qp->vif == arg->vif; |
| } |
| |
| 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 ip4_create_arg *arg = a; |
| |
| qp->protocol = arg->iph->protocol; |
| qp->id = arg->iph->id; |
| qp->ecn = ip4_frag_ecn(arg->iph->tos); |
| qp->saddr = arg->iph->saddr; |
| qp->daddr = arg->iph->daddr; |
| qp->vif = arg->vif; |
| qp->user = arg->user; |
| qp->peer = q->net->max_dist ? |
| inet_getpeer_v4(net->ipv4.peers, arg->iph->saddr, arg->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, &ip4_frags); |
| } |
| |
| /* 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, &ip4_frags); |
| } |
| |
| 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); |
| struct ipq *qp; |
| struct net *net; |
| |
| 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); |
| |
| if (!inet_frag_evicting(&qp->q)) { |
| struct sk_buff *clone, *head = qp->q.fragments; |
| const struct iphdr *iph; |
| int err; |
| |
| __IP_INC_STATS(net, IPSTATS_MIB_REASMTIMEOUT); |
| |
| if (!(qp->q.flags & INET_FRAG_FIRST_IN) || !qp->q.fragments) |
| goto out; |
| |
| 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->user) && |
| (skb_rtable(head)->rt_type != RTN_LOCAL)) |
| goto out; |
| |
| clone = skb_clone(head, GFP_ATOMIC); |
| |
| /* Send an ICMP "Fragment Reassembly Timeout" message. */ |
| if (clone) { |
| spin_unlock(&qp->q.lock); |
| icmp_send(clone, ICMP_TIME_EXCEEDED, |
| ICMP_EXC_FRAGTIME, 0); |
| consume_skb(clone); |
| goto out_rcu_unlock; |
| } |
| } |
| out: |
| spin_unlock(&qp->q.lock); |
| out_rcu_unlock: |
| rcu_read_unlock(); |
| 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 inet_frag_queue *q; |
| struct ip4_create_arg arg; |
| unsigned int hash; |
| |
| arg.iph = iph; |
| arg.user = user; |
| arg.vif = vif; |
| |
| hash = ipqhashfn(iph->id, iph->saddr, iph->daddr, iph->protocol); |
| |
| q = inet_frag_find(&net->ipv4.frags, &ip4_frags, &arg, hash); |
| if (IS_ERR_OR_NULL(q)) { |
| inet_frag_maybe_warn_overflow(q, pr_fmt()); |
| 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 && (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) |
| { |
| struct sk_buff *fp; |
| unsigned int sum_truesize = 0; |
| |
| if (!mod_timer(&qp->q.timer, jiffies + qp->q.net->timeout)) { |
| refcount_inc(&qp->q.refcnt); |
| return -ETIMEDOUT; |
| } |
| |
| fp = qp->q.fragments; |
| do { |
| struct sk_buff *xp = fp->next; |
| |
| sum_truesize += fp->truesize; |
| kfree_skb(fp); |
| fp = xp; |
| } while (fp); |
| 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.fragments_tail = 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 sk_buff *prev, *next; |
| 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; |
| |
| /* 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 = qp->q.fragments_tail; |
| if (!prev || FRAG_CB(prev)->offset < offset) { |
| next = NULL; |
| goto found; |
| } |
| prev = NULL; |
| for (next = qp->q.fragments; next != NULL; next = next->next) { |
| if (FRAG_CB(next)->offset >= offset) |
| break; /* bingo! */ |
| prev = next; |
| } |
| |
| found: |
| /* 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; |
| err = -EINVAL; |
| if (end <= offset) |
| goto err; |
| err = -ENOMEM; |
| if (!pskb_pull(skb, i)) |
| goto err; |
| if (skb->ip_summed != CHECKSUM_UNNECESSARY) |
| skb->ip_summed = CHECKSUM_NONE; |
| } |
| } |
| |
| err = -ENOMEM; |
| |
| 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->q.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->q.fragments = next; |
| |
| qp->q.meat -= free_it->len; |
| sub_frag_mem_limit(qp->q.net, free_it->truesize); |
| kfree_skb(free_it); |
| } |
| } |
| |
| FRAG_CB(skb)->offset = offset; |
| |
| /* Insert this fragment in the chain of fragments. */ |
| skb->next = next; |
| if (!next) |
| qp->q.fragments_tail = skb; |
| if (prev) |
| prev->next = skb; |
| else |
| qp->q.fragments = skb; |
| |
| dev = skb->dev; |
| if (dev) { |
| qp->iif = dev->ifindex; |
| skb->dev = NULL; |
| } |
| 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, prev, dev); |
| skb->_skb_refdst = orefdst; |
| return err; |
| } |
| |
| skb_dst_drop(skb); |
| return -EINPROGRESS; |
| |
| 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 *prev, |
| struct net_device *dev) |
| { |
| struct net *net = container_of(qp->q.net, struct net, ipv4.frags); |
| struct iphdr *iph; |
| struct sk_buff *fp, *head = qp->q.fragments; |
| int len; |
| int ihlen; |
| 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 (prev) { |
| head = prev->next; |
| fp = skb_clone(head, GFP_ATOMIC); |
| if (!fp) |
| goto out_nomem; |
| |
| fp->next = head->next; |
| if (!fp->next) |
| qp->q.fragments_tail = fp; |
| prev->next = fp; |
| |
| skb_morph(head, qp->q.fragments); |
| head->next = qp->q.fragments->next; |
| |
| consume_skb(qp->q.fragments); |
| qp->q.fragments = head; |
| } |
| |
| WARN_ON(!head); |
| WARN_ON(FRAG_CB(head)->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; |
| |
| /* Head of list must not be cloned. */ |
| if (skb_unclone(head, 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_has_frag_list(head)) { |
| struct sk_buff *clone; |
| int i, plen = 0; |
| |
| clone = alloc_skb(0, GFP_ATOMIC); |
| if (!clone) |
| goto out_nomem; |
| clone->next = head->next; |
| head->next = clone; |
| 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->data_len -= clone->len; |
| head->len -= clone->len; |
| clone->csum = 0; |
| clone->ip_summed = head->ip_summed; |
| add_frag_mem_limit(qp->q.net, clone->truesize); |
| } |
| |
| skb_shinfo(head)->frag_list = head->next; |
| skb_push(head, head->data - skb_network_header(head)); |
| |
| 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; |
| } |
| sub_frag_mem_limit(qp->q.net, head->truesize); |
| |
| head->next = 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.fragments_tail = 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->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)) |
| return skb; |
| if (pskb_trim_rcsum(skb, netoff + len)) |
| return skb; |
| 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); |
| |
| #ifdef CONFIG_SYSCTL |
| static int zero; |
| |
| static struct ctl_table ip4_frags_ns_ctl_table[] = { |
| { |
| .procname = "ipfrag_high_thresh", |
| .data = &init_net.ipv4.frags.high_thresh, |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_minmax, |
| .extra1 = &init_net.ipv4.frags.low_thresh |
| }, |
| { |
| .procname = "ipfrag_low_thresh", |
| .data = &init_net.ipv4.frags.low_thresh, |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_minmax, |
| .extra1 = &zero, |
| .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 = &zero |
| }, |
| { } |
| }; |
| |
| /* 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) |
| { |
| /* 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; |
| |
| inet_frags_init_net(&net->ipv4.frags); |
| |
| return ip4_frags_ns_ctl_register(net); |
| } |
| |
| static void __net_exit ipv4_frags_exit_net(struct net *net) |
| { |
| ip4_frags_ns_ctl_unregister(net); |
| inet_frags_exit_net(&net->ipv4.frags, &ip4_frags); |
| } |
| |
| static struct pernet_operations ip4_frags_ops = { |
| .init = ipv4_frags_init_net, |
| .exit = ipv4_frags_exit_net, |
| .async = true, |
| }; |
| |
| void __init ipfrag_init(void) |
| { |
| ip4_frags_ctl_register(); |
| register_pernet_subsys(&ip4_frags_ops); |
| ip4_frags.hashfn = ip4_hashfn; |
| ip4_frags.constructor = ip4_frag_init; |
| ip4_frags.destructor = ip4_frag_free; |
| ip4_frags.qsize = sizeof(struct ipq); |
| ip4_frags.match = ip4_frag_match; |
| ip4_frags.frag_expire = ip_expire; |
| ip4_frags.frags_cache_name = ip_frag_cache_name; |
| if (inet_frags_init(&ip4_frags)) |
| panic("IP: failed to allocate ip4_frags cache\n"); |
| } |