6lowpan: handling 6lowpan fragmentation via inet_frag api
authorAlexander Aring <alex.aring@gmail.com>
Fri, 28 Feb 2014 06:32:50 +0000 (07:32 +0100)
committerDavid S. Miller <davem@davemloft.net>
Fri, 28 Feb 2014 22:05:22 +0000 (17:05 -0500)
This patch drops the current way of 6lowpan fragmentation on receiving
side and replace it with a implementation which use the inet_frag api.
The old fragmentation handling has some race conditions and isn't
rfc4944 compatible. Also adding support to match fragments on
destination address, source address, tag value and datagram_size
which is missing in the current implementation.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
include/net/netns/ieee802154_6lowpan.h
net/ieee802154/6lowpan_rtnl.c
net/ieee802154/Makefile
net/ieee802154/reassembly.c [new file with mode: 0644]
net/ieee802154/reassembly.h [new file with mode: 0644]

index 88110b7e242874cd0ace83485786c0ab41e12f79..079030c853d856d0604f5600154d57e79ab70515 100644 (file)
@@ -7,7 +7,16 @@
 #ifndef __NETNS_IEEE802154_6LOWPAN_H__
 #define __NETNS_IEEE802154_6LOWPAN_H__
 
+struct netns_sysctl_lowpan {
+#ifdef CONFIG_SYSCTL
+       struct ctl_table_header *frags_hdr;
+#endif
+};
+
 struct netns_ieee802154_lowpan {
+       struct netns_sysctl_lowpan sysctl;
+       struct netns_frags      frags;
+       u16                     max_dsize;
 };
 
 #endif
index f9c954824ddb86f1d6131565650070006d859130..c7bd8b55f7ce20d1952d17fc42d7266ee5a38343 100644 (file)
@@ -54,6 +54,7 @@
 #include <net/ieee802154_netdev.h>
 #include <net/ipv6.h>
 
+#include "reassembly.h"
 #include "6lowpan.h"
 
 static LIST_HEAD(lowpan_devices);
@@ -70,18 +71,6 @@ struct lowpan_dev_record {
        struct list_head list;
 };
 
-struct lowpan_fragment {
-       struct sk_buff          *skb;           /* skb to be assembled */
-       u16                     length;         /* length to be assemled */
-       u32                     bytes_rcv;      /* bytes received */
-       u16                     tag;            /* current fragment tag */
-       struct timer_list       timer;          /* assembling timer */
-       struct list_head        list;           /* fragments list */
-};
-
-static LIST_HEAD(lowpan_fragments);
-static DEFINE_SPINLOCK(flist_lock);
-
 static inline struct
 lowpan_dev_info *lowpan_dev_info(const struct net_device *dev)
 {
@@ -179,69 +168,6 @@ static int lowpan_give_skb_to_devices(struct sk_buff *skb,
        return stat;
 }
 
-static void lowpan_fragment_timer_expired(unsigned long entry_addr)
-{
-       struct lowpan_fragment *entry = (struct lowpan_fragment *)entry_addr;
-
-       pr_debug("timer expired for frame with tag %d\n", entry->tag);
-
-       list_del(&entry->list);
-       dev_kfree_skb(entry->skb);
-       kfree(entry);
-}
-
-static struct lowpan_fragment *
-lowpan_alloc_new_frame(struct sk_buff *skb, u16 len, u16 tag)
-{
-       struct lowpan_fragment *frame;
-
-       frame = kzalloc(sizeof(struct lowpan_fragment),
-                       GFP_ATOMIC);
-       if (!frame)
-               goto frame_err;
-
-       INIT_LIST_HEAD(&frame->list);
-
-       frame->length = len;
-       frame->tag = tag;
-
-       /* allocate buffer for frame assembling */
-       frame->skb = netdev_alloc_skb_ip_align(skb->dev, frame->length +
-                                              sizeof(struct ipv6hdr));
-
-       if (!frame->skb)
-               goto skb_err;
-
-       frame->skb->priority = skb->priority;
-
-       /* reserve headroom for uncompressed ipv6 header */
-       skb_reserve(frame->skb, sizeof(struct ipv6hdr));
-       skb_put(frame->skb, frame->length);
-
-       /* copy the first control block to keep a
-        * trace of the link-layer addresses in case
-        * of a link-local compressed address
-        */
-       memcpy(frame->skb->cb, skb->cb, sizeof(skb->cb));
-
-       init_timer(&frame->timer);
-       /* time out is the same as for ipv6 - 60 sec */
-       frame->timer.expires = jiffies + LOWPAN_FRAG_TIMEOUT;
-       frame->timer.data = (unsigned long)frame;
-       frame->timer.function = lowpan_fragment_timer_expired;
-
-       add_timer(&frame->timer);
-
-       list_add_tail(&frame->list, &lowpan_fragments);
-
-       return frame;
-
-skb_err:
-       kfree(frame);
-frame_err:
-       return NULL;
-}
-
 static int process_data(struct sk_buff *skb)
 {
        u8 iphc0, iphc1;
@@ -255,94 +181,6 @@ static int process_data(struct sk_buff *skb)
        if (lowpan_fetch_skb_u8(skb, &iphc0))
                goto drop;
 
-       /* fragments assembling */
-       switch (iphc0 & LOWPAN_DISPATCH_MASK) {
-       case LOWPAN_DISPATCH_FRAG1:
-       case LOWPAN_DISPATCH_FRAGN:
-       {
-               struct lowpan_fragment *frame;
-               /* slen stores the rightmost 8 bits of the 11 bits length */
-               u8 slen, offset = 0;
-               u16 len, tag;
-               bool found = false;
-
-               if (lowpan_fetch_skb_u8(skb, &slen) || /* frame length */
-                   lowpan_fetch_skb_u16(skb, &tag))  /* fragment tag */
-                       goto drop;
-
-               /* adds the 3 MSB to the 8 LSB to retrieve the 11 bits length */
-               len = ((iphc0 & 7) << 8) | slen;
-
-               if ((iphc0 & LOWPAN_DISPATCH_MASK) == LOWPAN_DISPATCH_FRAG1) {
-                       pr_debug("%s received a FRAG1 packet (tag: %d, "
-                                "size of the entire IP packet: %d)",
-                                __func__, tag, len);
-               } else { /* FRAGN */
-                       if (lowpan_fetch_skb_u8(skb, &offset))
-                               goto unlock_and_drop;
-                       pr_debug("%s received a FRAGN packet (tag: %d, "
-                                "size of the entire IP packet: %d, "
-                                "offset: %d)", __func__, tag, len, offset * 8);
-               }
-
-               /*
-                * check if frame assembling with the same tag is
-                * already in progress
-                */
-               spin_lock_bh(&flist_lock);
-
-               list_for_each_entry(frame, &lowpan_fragments, list)
-                       if (frame->tag == tag) {
-                               found = true;
-                               break;
-                       }
-
-               /* alloc new frame structure */
-               if (!found) {
-                       pr_debug("%s first fragment received for tag %d, "
-                                "begin packet reassembly", __func__, tag);
-                       frame = lowpan_alloc_new_frame(skb, len, tag);
-                       if (!frame)
-                               goto unlock_and_drop;
-               }
-
-               /* if payload fits buffer, copy it */
-               if (likely((offset * 8 + skb->len) <= frame->length))
-                       skb_copy_to_linear_data_offset(frame->skb, offset * 8,
-                                                       skb->data, skb->len);
-               else
-                       goto unlock_and_drop;
-
-               frame->bytes_rcv += skb->len;
-
-               /* frame assembling complete */
-               if ((frame->bytes_rcv == frame->length) &&
-                    frame->timer.expires > jiffies) {
-                       /* if timer haven't expired - first of all delete it */
-                       del_timer_sync(&frame->timer);
-                       list_del(&frame->list);
-                       spin_unlock_bh(&flist_lock);
-
-                       pr_debug("%s successfully reassembled fragment "
-                                "(tag %d)", __func__, tag);
-
-                       dev_kfree_skb(skb);
-                       skb = frame->skb;
-                       kfree(frame);
-
-                       if (lowpan_fetch_skb_u8(skb, &iphc0))
-                               goto drop;
-
-                       break;
-               }
-               spin_unlock_bh(&flist_lock);
-
-               return kfree_skb(skb), 0;
-       }
-       default:
-               break;
-       }
-
        if (lowpan_fetch_skb_u8(skb, &iphc1))
                goto drop;
 
@@ -355,8 +193,6 @@ static int process_data(struct sk_buff *skb)
                                IEEE802154_ADDR_LEN, iphc0, iphc1,
                                lowpan_give_skb_to_devices);
 
-unlock_and_drop:
-       spin_unlock_bh(&flist_lock);
 drop:
        kfree_skb(skb);
        return -EINVAL;
@@ -603,44 +439,53 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
        struct packet_type *pt, struct net_device *orig_dev)
 {
        struct sk_buff *local_skb;
+       int ret;
 
        if (!netif_running(dev))
-               goto drop;
+               goto drop_skb;
 
        if (dev->type != ARPHRD_IEEE802154)
-               goto drop;
+               goto drop_skb;
+
+       local_skb = skb_clone(skb, GFP_ATOMIC);
+       if (!local_skb)
+               goto drop_skb;
+
+       kfree_skb(skb);
 
        /* check that it's our buffer */
        if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
-               /* Copy the packet so that the IPv6 header is
-                * properly aligned.
-                */
-               local_skb = skb_copy_expand(skb, NET_SKB_PAD - 1,
-                                           skb_tailroom(skb), GFP_ATOMIC);
-               if (!local_skb)
-                       goto drop;
-
                local_skb->protocol = htons(ETH_P_IPV6);
                local_skb->pkt_type = PACKET_HOST;
 
                /* Pull off the 1-byte of 6lowpan header. */
                skb_pull(local_skb, 1);
 
-               lowpan_give_skb_to_devices(local_skb, NULL);
-
-               kfree_skb(local_skb);
-               kfree_skb(skb);
+               ret = lowpan_give_skb_to_devices(local_skb, NULL);
+               if (ret == NET_RX_DROP)
+                       goto drop;
        } else {
                switch (skb->data[0] & 0xe0) {
                case LOWPAN_DISPATCH_IPHC:      /* ipv6 datagram */
+                       ret = process_data(local_skb);
+                       if (ret == NET_RX_DROP)
+                               goto drop;
+                       break;
                case LOWPAN_DISPATCH_FRAG1:     /* first fragment header */
+                       ret = lowpan_frag_rcv(local_skb, LOWPAN_DISPATCH_FRAG1);
+                       if (ret == 1) {
+                               ret = process_data(local_skb);
+                               if (ret == NET_RX_DROP)
+                                       goto drop;
+                       }
+                       break;
                case LOWPAN_DISPATCH_FRAGN:     /* next fragments headers */
-                       local_skb = skb_clone(skb, GFP_ATOMIC);
-                       if (!local_skb)
-                               goto drop;
-                       process_data(local_skb);
-
-                       kfree_skb(skb);
+                       ret = lowpan_frag_rcv(local_skb, LOWPAN_DISPATCH_FRAGN);
+                       if (ret == 1) {
+                               ret = process_data(local_skb);
+                               if (ret == NET_RX_DROP)
+                                       goto drop;
+                       }
                        break;
                default:
                        break;
@@ -648,9 +493,9 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
        }
 
        return NET_RX_SUCCESS;
-
-drop:
+drop_skb:
        kfree_skb(skb);
+drop:
        return NET_RX_DROP;
 }
 
@@ -778,43 +623,40 @@ static int __init lowpan_init_module(void)
 {
        int err = 0;
 
-       err = lowpan_netlink_init();
+       err = lowpan_net_frag_init();
        if (err < 0)
                goto out;
 
+       err = lowpan_netlink_init();
+       if (err < 0)
+               goto out_frag;
+
        dev_add_pack(&lowpan_packet_type);
 
        err = register_netdevice_notifier(&lowpan_dev_notifier);
-       if (err < 0) {
-               dev_remove_pack(&lowpan_packet_type);
-               lowpan_netlink_fini();
-       }
+       if (err < 0)
+               goto out_pack;
+
+       return 0;
+
+out_pack:
+       dev_remove_pack(&lowpan_packet_type);
+       lowpan_netlink_fini();
+out_frag:
+       lowpan_net_frag_exit();
 out:
        return err;
 }
 
 static void __exit lowpan_cleanup_module(void)
 {
-       struct lowpan_fragment *frame, *tframe;
-
        lowpan_netlink_fini();
 
        dev_remove_pack(&lowpan_packet_type);
 
-       unregister_netdevice_notifier(&lowpan_dev_notifier);
+       lowpan_net_frag_exit();
 
-       /* Now 6lowpan packet_type is removed, so no new fragments are
-        * expected on RX, therefore that's the time to clean incomplete
-        * fragments.
-        */
-       spin_lock_bh(&flist_lock);
-       list_for_each_entry_safe(frame, tframe, &lowpan_fragments, list) {
-               del_timer_sync(&frame->timer);
-               list_del(&frame->list);
-               dev_kfree_skb(frame->skb);
-               kfree(frame);
-       }
-       spin_unlock_bh(&flist_lock);
+       unregister_netdevice_notifier(&lowpan_dev_notifier);
 }
 
 module_init(lowpan_init_module);
index 3d08adfcd1750ab3902d23aa231e9c29d0a68326..b113fc4be3e0e7f651b49b2fc955089deb78c8b2 100644 (file)
@@ -2,6 +2,6 @@ obj-$(CONFIG_IEEE802154) += ieee802154.o af_802154.o
 obj-$(CONFIG_IEEE802154_6LOWPAN) += 6lowpan.o
 obj-$(CONFIG_6LOWPAN_IPHC) += 6lowpan_iphc.o
 
-6lowpan-y := 6lowpan_rtnl.o
+6lowpan-y := 6lowpan_rtnl.o reassembly.o
 ieee802154-y := netlink.o nl-mac.o nl-phy.o nl_policy.o wpan-class.o
 af_802154-y := af_ieee802154.o raw.o dgram.o
diff --git a/net/ieee802154/reassembly.c b/net/ieee802154/reassembly.c
new file mode 100644 (file)
index 0000000..eb5995e
--- /dev/null
@@ -0,0 +1,564 @@
+/*     6LoWPAN fragment reassembly
+ *
+ *
+ *     Authors:
+ *     Alexander Aring         <aar@pengutronix.de>
+ *
+ *     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.
+ */
+
+#define pr_fmt(fmt) "6LoWPAN: " fmt
+
+#include <linux/net.h>
+#include <linux/list.h>
+#include <linux/netdevice.h>
+#include <linux/random.h>
+#include <linux/jhash.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+
+#include <net/ieee802154_netdev.h>
+#include <net/ipv6.h>
+#include <net/inet_frag.h>
+
+#include "6lowpan.h"
+#include "reassembly.h"
+
+static struct inet_frags lowpan_frags;
+
+static int lowpan_frag_reasm(struct lowpan_frag_queue *fq,
+                            struct sk_buff *prev, struct net_device *dev);
+
+static unsigned int lowpan_hash_frag(__be16 tag, __be16 d_size,
+                                    const struct ieee802154_addr *saddr,
+                                    const struct ieee802154_addr *daddr)
+{
+       u32 c;
+
+       net_get_random_once(&lowpan_frags.rnd, sizeof(lowpan_frags.rnd));
+       c = jhash_3words(ieee802154_addr_hash(saddr),
+                        ieee802154_addr_hash(daddr),
+                        (__force u32)(tag + (d_size << 16)),
+                        lowpan_frags.rnd);
+
+       return c & (INETFRAGS_HASHSZ - 1);
+}
+
+static unsigned int lowpan_hashfn(struct inet_frag_queue *q)
+{
+       struct lowpan_frag_queue *fq;
+
+       fq = container_of(q, struct lowpan_frag_queue, q);
+       return lowpan_hash_frag(fq->tag, fq->d_size, &fq->saddr, &fq->daddr);
+}
+
+bool lowpan_frag_match(struct inet_frag_queue *q, void *a)
+{
+       struct lowpan_frag_queue *fq;
+       struct lowpan_create_arg *arg = a;
+
+       fq = container_of(q, struct lowpan_frag_queue, q);
+       return  fq->tag == arg->tag && fq->d_size == arg->d_size &&
+               ieee802154_addr_addr_equal(&fq->saddr, arg->src) &&
+               ieee802154_addr_addr_equal(&fq->daddr, arg->dst);
+}
+EXPORT_SYMBOL(lowpan_frag_match);
+
+void lowpan_frag_init(struct inet_frag_queue *q, void *a)
+{
+       struct lowpan_frag_queue *fq;
+       struct lowpan_create_arg *arg = a;
+
+       fq = container_of(q, struct lowpan_frag_queue, q);
+
+       fq->tag = arg->tag;
+       fq->d_size = arg->d_size;
+       fq->saddr = *arg->src;
+       fq->daddr = *arg->dst;
+}
+EXPORT_SYMBOL(lowpan_frag_init);
+
+void lowpan_expire_frag_queue(struct frag_queue *fq, struct inet_frags *frags)
+{
+       spin_lock(&fq->q.lock);
+
+       if (fq->q.last_in & INET_FRAG_COMPLETE)
+               goto out;
+
+       inet_frag_kill(&fq->q, frags);
+out:
+       spin_unlock(&fq->q.lock);
+       inet_frag_put(&fq->q, frags);
+}
+EXPORT_SYMBOL(lowpan_expire_frag_queue);
+
+static void lowpan_frag_expire(unsigned long data)
+{
+       struct frag_queue *fq;
+       struct net *net;
+
+       fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
+       net = container_of(fq->q.net, struct net, ieee802154_lowpan.frags);
+
+       lowpan_expire_frag_queue(fq, &lowpan_frags);
+}
+
+static inline struct lowpan_frag_queue *
+fq_find(struct net *net, const struct ieee802154_frag_info *frag_info,
+       const struct ieee802154_addr *src, const struct ieee802154_addr *dst)
+{
+       struct inet_frag_queue *q;
+       struct lowpan_create_arg arg;
+       unsigned int hash;
+
+       arg.tag = frag_info->d_tag;
+       arg.d_size = frag_info->d_size;
+       arg.src = src;
+       arg.dst = dst;
+
+       read_lock(&lowpan_frags.lock);
+       hash = lowpan_hash_frag(frag_info->d_tag, frag_info->d_size, src, dst);
+
+       q = inet_frag_find(&net->ieee802154_lowpan.frags,
+                          &lowpan_frags, &arg, hash);
+       if (IS_ERR_OR_NULL(q)) {
+               inet_frag_maybe_warn_overflow(q, pr_fmt());
+               return NULL;
+       }
+       return container_of(q, struct lowpan_frag_queue, q);
+}
+
+static int lowpan_frag_queue(struct lowpan_frag_queue *fq,
+                            struct sk_buff *skb, const u8 frag_type)
+{
+       struct sk_buff *prev, *next;
+       struct net_device *dev;
+       int end, offset;
+
+       if (fq->q.last_in & INET_FRAG_COMPLETE)
+               goto err;
+
+       offset = mac_cb(skb)->frag_info.d_offset << 3;
+       end = mac_cb(skb)->frag_info.d_size;
+
+       /* Is this the final fragment? */
+       if (offset + skb->len == end) {
+               /* If we already have some bits beyond end
+                * or have different end, the segment is corrupted.
+                */
+               if (end < fq->q.len ||
+                   ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
+                       goto err;
+               fq->q.last_in |= INET_FRAG_LAST_IN;
+               fq->q.len = end;
+       } else {
+               if (end > fq->q.len) {
+                       /* Some bits beyond end -> corruption. */
+                       if (fq->q.last_in & INET_FRAG_LAST_IN)
+                               goto err;
+                       fq->q.len = end;
+               }
+       }
+
+       /* 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 = fq->q.fragments_tail;
+       if (!prev || mac_cb(prev)->frag_info.d_offset <
+                    mac_cb(skb)->frag_info.d_offset) {
+               next = NULL;
+               goto found;
+       }
+       prev = NULL;
+       for (next = fq->q.fragments; next != NULL; next = next->next) {
+               if (mac_cb(next)->frag_info.d_offset >=
+                   mac_cb(skb)->frag_info.d_offset)
+                       break;  /* bingo! */
+               prev = next;
+       }
+
+found:
+       /* Insert this fragment in the chain of fragments. */
+       skb->next = next;
+       if (!next)
+               fq->q.fragments_tail = skb;
+       if (prev)
+               prev->next = skb;
+       else
+               fq->q.fragments = skb;
+
+       dev = skb->dev;
+       if (dev)
+               skb->dev = NULL;
+
+       fq->q.stamp = skb->tstamp;
+       if (frag_type == LOWPAN_DISPATCH_FRAG1) {
+               /* Calculate uncomp. 6lowpan header to estimate full size */
+               fq->q.meat += lowpan_uncompress_size(skb, NULL);
+               fq->q.last_in |= INET_FRAG_FIRST_IN;
+       } else {
+               fq->q.meat += skb->len;
+       }
+       add_frag_mem_limit(&fq->q, skb->truesize);
+
+       if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
+           fq->q.meat == fq->q.len) {
+               int res;
+               unsigned long orefdst = skb->_skb_refdst;
+
+               skb->_skb_refdst = 0UL;
+               res = lowpan_frag_reasm(fq, prev, dev);
+               skb->_skb_refdst = orefdst;
+               return res;
+       }
+
+       inet_frag_lru_move(&fq->q);
+       return -1;
+err:
+       kfree_skb(skb);
+       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 int lowpan_frag_reasm(struct lowpan_frag_queue *fq, struct sk_buff *prev,
+                            struct net_device *dev)
+{
+       struct sk_buff *fp, *head = fq->q.fragments;
+       int sum_truesize;
+
+       inet_frag_kill(&fq->q, &lowpan_frags);
+
+       /* Make the one we just received the head. */
+       if (prev) {
+               head = prev->next;
+               fp = skb_clone(head, GFP_ATOMIC);
+
+               if (!fp)
+                       goto out_oom;
+
+               fp->next = head->next;
+               if (!fp->next)
+                       fq->q.fragments_tail = fp;
+               prev->next = fp;
+
+               skb_morph(head, fq->q.fragments);
+               head->next = fq->q.fragments->next;
+
+               consume_skb(fq->q.fragments);
+               fq->q.fragments = head;
+       }
+
+       /* Head of list must not be cloned. */
+       if (skb_unclone(head, 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_has_frag_list(head)) {
+               struct sk_buff *clone;
+               int i, plen = 0;
+
+               clone = alloc_skb(0, GFP_ATOMIC);
+               if (!clone)
+                       goto out_oom;
+               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 = head->data_len - plen;
+               clone->data_len = clone->len;
+               head->data_len -= clone->len;
+               head->len -= clone->len;
+               add_frag_mem_limit(&fq->q, clone->truesize);
+       }
+
+       WARN_ON(head == NULL);
+
+       sum_truesize = head->truesize;
+       for (fp = head->next; fp;) {
+               bool headstolen;
+               int delta;
+               struct sk_buff *next = fp->next;
+
+               sum_truesize += fp->truesize;
+               if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
+                       kfree_skb_partial(fp, headstolen);
+               } else {
+                       if (!skb_shinfo(head)->frag_list)
+                               skb_shinfo(head)->frag_list = fp;
+                       head->data_len += fp->len;
+                       head->len += fp->len;
+                       head->truesize += fp->truesize;
+               }
+               fp = next;
+       }
+       sub_frag_mem_limit(&fq->q, sum_truesize);
+
+       head->next = NULL;
+       head->dev = dev;
+       head->tstamp = fq->q.stamp;
+
+       fq->q.fragments = NULL;
+       fq->q.fragments_tail = NULL;
+
+       return 1;
+out_oom:
+       net_dbg_ratelimited("lowpan_frag_reasm: no memory for reassembly\n");
+       return -1;
+}
+
+static int lowpan_get_frag_info(struct sk_buff *skb, const u8 frag_type,
+                               struct ieee802154_frag_info *frag_info)
+{
+       bool fail;
+       u8 pattern = 0, low = 0;
+
+       fail = lowpan_fetch_skb(skb, &pattern, 1);
+       fail |= lowpan_fetch_skb(skb, &low, 1);
+       frag_info->d_size = (pattern & 7) << 8 | low;
+       fail |= lowpan_fetch_skb(skb, &frag_info->d_tag, 2);
+
+       if (frag_type == LOWPAN_DISPATCH_FRAGN) {
+               fail |= lowpan_fetch_skb(skb, &frag_info->d_offset, 1);
+       } else {
+               skb_reset_network_header(skb);
+               frag_info->d_offset = 0;
+       }
+
+       if (unlikely(fail))
+               return -EIO;
+
+       return 0;
+}
+
+int lowpan_frag_rcv(struct sk_buff *skb, const u8 frag_type)
+{
+       struct lowpan_frag_queue *fq;
+       struct net *net = dev_net(skb->dev);
+       struct ieee802154_frag_info *frag_info = &mac_cb(skb)->frag_info;
+       int err;
+
+       err = lowpan_get_frag_info(skb, frag_type, frag_info);
+       if (err < 0)
+               goto err;
+
+       if (frag_info->d_size > net->ieee802154_lowpan.max_dsize)
+               goto err;
+
+       inet_frag_evictor(&net->ieee802154_lowpan.frags, &lowpan_frags, false);
+
+       fq = fq_find(net, frag_info, &mac_cb(skb)->sa, &mac_cb(skb)->da);
+       if (fq != NULL) {
+               int ret;
+               spin_lock(&fq->q.lock);
+               ret = lowpan_frag_queue(fq, skb, frag_type);
+               spin_unlock(&fq->q.lock);
+
+               inet_frag_put(&fq->q, &lowpan_frags);
+               return ret;
+       }
+
+err:
+       kfree_skb(skb);
+       return -1;
+}
+EXPORT_SYMBOL(lowpan_frag_rcv);
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table lowpan_frags_ns_ctl_table[] = {
+       {
+               .procname       = "6lowpanfrag_high_thresh",
+               .data           = &init_net.ieee802154_lowpan.frags.high_thresh,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec
+       },
+       {
+               .procname       = "6lowpanfrag_low_thresh",
+               .data           = &init_net.ieee802154_lowpan.frags.low_thresh,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec
+       },
+       {
+               .procname       = "6lowpanfrag_time",
+               .data           = &init_net.ieee802154_lowpan.frags.timeout,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec_jiffies,
+       },
+       {
+               .procname       = "6lowpanfrag_max_datagram_size",
+               .data           = &init_net.ieee802154_lowpan.max_dsize,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec
+       },
+       { }
+};
+
+static struct ctl_table lowpan_frags_ctl_table[] = {
+       {
+               .procname       = "6lowpanfrag_secret_interval",
+               .data           = &lowpan_frags.secret_interval,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec_jiffies,
+       },
+       { }
+};
+
+static int __net_init lowpan_frags_ns_sysctl_register(struct net *net)
+{
+       struct ctl_table *table;
+       struct ctl_table_header *hdr;
+
+       table = lowpan_frags_ns_ctl_table;
+       if (!net_eq(net, &init_net)) {
+               table = kmemdup(table, sizeof(lowpan_frags_ns_ctl_table),
+                               GFP_KERNEL);
+               if (table == NULL)
+                       goto err_alloc;
+
+               table[0].data = &net->ieee802154_lowpan.frags.high_thresh;
+               table[1].data = &net->ieee802154_lowpan.frags.low_thresh;
+               table[2].data = &net->ieee802154_lowpan.frags.timeout;
+               table[2].data = &net->ieee802154_lowpan.max_dsize;
+
+               /* Don't export sysctls to unprivileged users */
+               if (net->user_ns != &init_user_ns)
+                       table[0].procname = NULL;
+       }
+
+       hdr = register_net_sysctl(net, "net/ieee802154/6lowpan", table);
+       if (hdr == NULL)
+               goto err_reg;
+
+       net->ieee802154_lowpan.sysctl.frags_hdr = hdr;
+       return 0;
+
+err_reg:
+       if (!net_eq(net, &init_net))
+               kfree(table);
+err_alloc:
+       return -ENOMEM;
+}
+
+static void __net_exit lowpan_frags_ns_sysctl_unregister(struct net *net)
+{
+       struct ctl_table *table;
+
+       table = net->ieee802154_lowpan.sysctl.frags_hdr->ctl_table_arg;
+       unregister_net_sysctl_table(net->ieee802154_lowpan.sysctl.frags_hdr);
+       if (!net_eq(net, &init_net))
+               kfree(table);
+}
+
+static struct ctl_table_header *lowpan_ctl_header;
+
+static int lowpan_frags_sysctl_register(void)
+{
+       lowpan_ctl_header = register_net_sysctl(&init_net,
+                                               "net/ieee802154/6lowpan",
+                                               lowpan_frags_ctl_table);
+       return lowpan_ctl_header == NULL ? -ENOMEM : 0;
+}
+
+static void lowpan_frags_sysctl_unregister(void)
+{
+       unregister_net_sysctl_table(lowpan_ctl_header);
+}
+#else
+static inline int lowpan_frags_ns_sysctl_register(struct net *net)
+{
+       return 0;
+}
+
+static inline void lowpan_frags_ns_sysctl_unregister(struct net *net)
+{
+}
+
+static inline int lowpan_frags_sysctl_register(void)
+{
+       return 0;
+}
+
+static inline void lowpan_frags_sysctl_unregister(void)
+{
+}
+#endif
+
+static int __net_init lowpan_frags_init_net(struct net *net)
+{
+       net->ieee802154_lowpan.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
+       net->ieee802154_lowpan.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
+       net->ieee802154_lowpan.frags.timeout = IPV6_FRAG_TIMEOUT;
+       net->ieee802154_lowpan.max_dsize = 0xFFFF;
+
+       inet_frags_init_net(&net->ieee802154_lowpan.frags);
+
+       return lowpan_frags_ns_sysctl_register(net);
+}
+
+static void __net_exit lowpan_frags_exit_net(struct net *net)
+{
+       lowpan_frags_ns_sysctl_unregister(net);
+       inet_frags_exit_net(&net->ieee802154_lowpan.frags, &lowpan_frags);
+}
+
+static struct pernet_operations lowpan_frags_ops = {
+       .init = lowpan_frags_init_net,
+       .exit = lowpan_frags_exit_net,
+};
+
+int __init lowpan_net_frag_init(void)
+{
+       int ret;
+
+       ret = lowpan_frags_sysctl_register();
+       if (ret)
+               goto out;
+
+       ret = register_pernet_subsys(&lowpan_frags_ops);
+       if (ret)
+               goto err_pernet;
+
+       lowpan_frags.hashfn = lowpan_hashfn;
+       lowpan_frags.constructor = lowpan_frag_init;
+       lowpan_frags.destructor = NULL;
+       lowpan_frags.skb_free = NULL;
+       lowpan_frags.qsize = sizeof(struct frag_queue);
+       lowpan_frags.match = lowpan_frag_match;
+       lowpan_frags.frag_expire = lowpan_frag_expire;
+       lowpan_frags.secret_interval = 10 * 60 * HZ;
+       inet_frags_init(&lowpan_frags);
+err_pernet:
+       lowpan_frags_sysctl_unregister();
+out:
+       return ret;
+}
+
+void lowpan_net_frag_exit(void)
+{
+       inet_frags_fini(&lowpan_frags);
+       lowpan_frags_sysctl_unregister();
+       unregister_pernet_subsys(&lowpan_frags_ops);
+}
diff --git a/net/ieee802154/reassembly.h b/net/ieee802154/reassembly.h
new file mode 100644 (file)
index 0000000..055518b
--- /dev/null
@@ -0,0 +1,66 @@
+#ifndef __IEEE802154_6LOWPAN_REASSEMBLY_H__
+#define __IEEE802154_6LOWPAN_REASSEMBLY_H__
+
+#include <net/inet_frag.h>
+
+struct lowpan_create_arg {
+       __be16 tag;
+       u16 d_size;
+       const struct ieee802154_addr *src;
+       const struct ieee802154_addr *dst;
+};
+
+/* Equivalent of ipv4 struct ip
+ */
+struct lowpan_frag_queue {
+       struct inet_frag_queue  q;
+
+       __be16                  tag;
+       u16                     d_size;
+       struct ieee802154_addr  saddr;
+       struct ieee802154_addr  daddr;
+};
+
+static inline u32 ieee802154_addr_hash(const struct ieee802154_addr *a)
+{
+       switch (a->addr_type) {
+       case IEEE802154_ADDR_LONG:
+               return (__force u32)((((u32 *)a->hwaddr))[0] ^
+                                     ((u32 *)(a->hwaddr))[1]);
+       case IEEE802154_ADDR_SHORT:
+               return (__force u32)(a->short_addr);
+       default:
+               return 0;
+       }
+}
+
+static inline bool ieee802154_addr_addr_equal(const struct ieee802154_addr *a1,
+                                  const struct ieee802154_addr *a2)
+{
+       if (a1->pan_id != a2->pan_id)
+               return false;
+
+       if (a1->addr_type != a2->addr_type)
+               return false;
+
+       switch (a1->addr_type) {
+       case IEEE802154_ADDR_LONG:
+               if (memcmp(a1->hwaddr, a2->hwaddr, IEEE802154_ADDR_LEN))
+                       return false;
+               break;
+       case IEEE802154_ADDR_SHORT:
+               if (a1->short_addr != a2->short_addr)
+                       return false;
+               break;
+       default:
+               return false;
+       }
+
+       return true;
+}
+
+int lowpan_frag_rcv(struct sk_buff *skb, const u8 frag_type);
+void lowpan_net_frag_exit(void);
+int lowpan_net_frag_init(void);
+
+#endif /* __IEEE802154_6LOWPAN_REASSEMBLY_H__ */