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-rw-r--r--net/ieee802154/6lowpan/reassembly.c555
1 files changed, 555 insertions, 0 deletions
diff --git a/net/ieee802154/6lowpan/reassembly.c b/net/ieee802154/6lowpan/reassembly.c
new file mode 100644
index 0000000000..6dd960ec55
--- /dev/null
+++ b/net/ieee802154/6lowpan/reassembly.c
@@ -0,0 +1,555 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* 6LoWPAN fragment reassembly
+ *
+ * Authors:
+ * Alexander Aring <aar@pengutronix.de>
+ *
+ * Based on: net/ipv6/reassembly.c
+ */
+
+#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/6lowpan.h>
+#include <net/ipv6_frag.h>
+#include <net/inet_frag.h>
+#include <net/ip.h>
+
+#include "6lowpan_i.h"
+
+static const char lowpan_frags_cache_name[] = "lowpan-frags";
+
+static struct inet_frags lowpan_frags;
+
+static int lowpan_frag_reasm(struct lowpan_frag_queue *fq, struct sk_buff *skb,
+ struct sk_buff *prev, struct net_device *ldev);
+
+static void lowpan_frag_init(struct inet_frag_queue *q, const void *a)
+{
+ const struct frag_lowpan_compare_key *key = a;
+
+ BUILD_BUG_ON(sizeof(*key) > sizeof(q->key));
+ memcpy(&q->key, key, sizeof(*key));
+}
+
+static void lowpan_frag_expire(struct timer_list *t)
+{
+ struct inet_frag_queue *frag = from_timer(frag, t, timer);
+ struct frag_queue *fq;
+
+ fq = container_of(frag, struct frag_queue, q);
+
+ spin_lock(&fq->q.lock);
+
+ if (fq->q.flags & INET_FRAG_COMPLETE)
+ goto out;
+
+ inet_frag_kill(&fq->q);
+out:
+ spin_unlock(&fq->q.lock);
+ inet_frag_put(&fq->q);
+}
+
+static inline struct lowpan_frag_queue *
+fq_find(struct net *net, const struct lowpan_802154_cb *cb,
+ const struct ieee802154_addr *src,
+ const struct ieee802154_addr *dst)
+{
+ struct netns_ieee802154_lowpan *ieee802154_lowpan =
+ net_ieee802154_lowpan(net);
+ struct frag_lowpan_compare_key key = {};
+ struct inet_frag_queue *q;
+
+ key.tag = cb->d_tag;
+ key.d_size = cb->d_size;
+ key.src = *src;
+ key.dst = *dst;
+
+ q = inet_frag_find(ieee802154_lowpan->fqdir, &key);
+ if (!q)
+ 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, u8 frag_type)
+{
+ struct sk_buff *prev_tail;
+ struct net_device *ldev;
+ int end, offset, err;
+
+ /* inet_frag_queue_* functions use skb->cb; see struct ipfrag_skb_cb
+ * in inet_fragment.c
+ */
+ BUILD_BUG_ON(sizeof(struct lowpan_802154_cb) > sizeof(struct inet_skb_parm));
+ BUILD_BUG_ON(sizeof(struct lowpan_802154_cb) > sizeof(struct inet6_skb_parm));
+
+ if (fq->q.flags & INET_FRAG_COMPLETE)
+ goto err;
+
+ offset = lowpan_802154_cb(skb)->d_offset << 3;
+ end = lowpan_802154_cb(skb)->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.flags & INET_FRAG_LAST_IN) && end != fq->q.len))
+ goto err;
+ fq->q.flags |= INET_FRAG_LAST_IN;
+ fq->q.len = end;
+ } else {
+ if (end > fq->q.len) {
+ /* Some bits beyond end -> corruption. */
+ if (fq->q.flags & INET_FRAG_LAST_IN)
+ goto err;
+ fq->q.len = end;
+ }
+ }
+
+ ldev = skb->dev;
+ if (ldev)
+ skb->dev = NULL;
+ barrier();
+
+ prev_tail = fq->q.fragments_tail;
+ err = inet_frag_queue_insert(&fq->q, skb, offset, end);
+ if (err)
+ goto err;
+
+ fq->q.stamp = skb->tstamp;
+ fq->q.mono_delivery_time = skb->mono_delivery_time;
+ if (frag_type == LOWPAN_DISPATCH_FRAG1)
+ fq->q.flags |= INET_FRAG_FIRST_IN;
+
+ fq->q.meat += skb->len;
+ add_frag_mem_limit(fq->q.fqdir, skb->truesize);
+
+ if (fq->q.flags == (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, skb, prev_tail, ldev);
+ skb->_skb_refdst = orefdst;
+ return res;
+ }
+ skb_dst_drop(skb);
+
+ return -1;
+err:
+ kfree_skb(skb);
+ return -1;
+}
+
+/* Check if this packet is complete.
+ *
+ * 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 *skb,
+ struct sk_buff *prev_tail, struct net_device *ldev)
+{
+ void *reasm_data;
+
+ inet_frag_kill(&fq->q);
+
+ reasm_data = inet_frag_reasm_prepare(&fq->q, skb, prev_tail);
+ if (!reasm_data)
+ goto out_oom;
+ inet_frag_reasm_finish(&fq->q, skb, reasm_data, false);
+
+ skb->dev = ldev;
+ skb->tstamp = fq->q.stamp;
+ fq->q.rb_fragments = RB_ROOT;
+ fq->q.fragments_tail = NULL;
+ fq->q.last_run_head = NULL;
+
+ return 1;
+out_oom:
+ net_dbg_ratelimited("lowpan_frag_reasm: no memory for reassembly\n");
+ return -1;
+}
+
+static int lowpan_frag_rx_handlers_result(struct sk_buff *skb,
+ lowpan_rx_result res)
+{
+ switch (res) {
+ case RX_QUEUED:
+ return NET_RX_SUCCESS;
+ case RX_CONTINUE:
+ /* nobody cared about this packet */
+ net_warn_ratelimited("%s: received unknown dispatch\n",
+ __func__);
+
+ fallthrough;
+ default:
+ /* all others failure */
+ return NET_RX_DROP;
+ }
+}
+
+static lowpan_rx_result lowpan_frag_rx_h_iphc(struct sk_buff *skb)
+{
+ int ret;
+
+ if (!lowpan_is_iphc(*skb_network_header(skb)))
+ return RX_CONTINUE;
+
+ ret = lowpan_iphc_decompress(skb);
+ if (ret < 0)
+ return RX_DROP;
+
+ return RX_QUEUED;
+}
+
+static int lowpan_invoke_frag_rx_handlers(struct sk_buff *skb)
+{
+ lowpan_rx_result res;
+
+#define CALL_RXH(rxh) \
+ do { \
+ res = rxh(skb); \
+ if (res != RX_CONTINUE) \
+ goto rxh_next; \
+ } while (0)
+
+ /* likely at first */
+ CALL_RXH(lowpan_frag_rx_h_iphc);
+ CALL_RXH(lowpan_rx_h_ipv6);
+
+rxh_next:
+ return lowpan_frag_rx_handlers_result(skb, res);
+#undef CALL_RXH
+}
+
+#define LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK 0x07
+#define LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT 8
+
+static int lowpan_get_cb(struct sk_buff *skb, u8 frag_type,
+ struct lowpan_802154_cb *cb)
+{
+ bool fail;
+ u8 high = 0, low = 0;
+ __be16 d_tag = 0;
+
+ fail = lowpan_fetch_skb(skb, &high, 1);
+ fail |= lowpan_fetch_skb(skb, &low, 1);
+ /* remove the dispatch value and use first three bits as high value
+ * for the datagram size
+ */
+ cb->d_size = (high & LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK) <<
+ LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT | low;
+ fail |= lowpan_fetch_skb(skb, &d_tag, 2);
+ cb->d_tag = ntohs(d_tag);
+
+ if (frag_type == LOWPAN_DISPATCH_FRAGN) {
+ fail |= lowpan_fetch_skb(skb, &cb->d_offset, 1);
+ } else {
+ skb_reset_network_header(skb);
+ cb->d_offset = 0;
+ /* check if datagram_size has ipv6hdr on FRAG1 */
+ fail |= cb->d_size < sizeof(struct ipv6hdr);
+ /* check if we can dereference the dispatch value */
+ fail |= !skb->len;
+ }
+
+ if (unlikely(fail))
+ return -EIO;
+
+ return 0;
+}
+
+int lowpan_frag_rcv(struct sk_buff *skb, u8 frag_type)
+{
+ struct lowpan_frag_queue *fq;
+ struct net *net = dev_net(skb->dev);
+ struct lowpan_802154_cb *cb = lowpan_802154_cb(skb);
+ struct ieee802154_hdr hdr = {};
+ int err;
+
+ if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
+ goto err;
+
+ err = lowpan_get_cb(skb, frag_type, cb);
+ if (err < 0)
+ goto err;
+
+ if (frag_type == LOWPAN_DISPATCH_FRAG1) {
+ err = lowpan_invoke_frag_rx_handlers(skb);
+ if (err == NET_RX_DROP)
+ goto err;
+ }
+
+ if (cb->d_size > IPV6_MIN_MTU) {
+ net_warn_ratelimited("lowpan_frag_rcv: datagram size exceeds MTU\n");
+ goto err;
+ }
+
+ fq = fq_find(net, cb, &hdr.source, &hdr.dest);
+ 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);
+ return ret;
+ }
+
+err:
+ kfree_skb(skb);
+ return -1;
+}
+
+#ifdef CONFIG_SYSCTL
+
+static struct ctl_table lowpan_frags_ns_ctl_table[] = {
+ {
+ .procname = "6lowpanfrag_high_thresh",
+ .maxlen = sizeof(unsigned long),
+ .mode = 0644,
+ .proc_handler = proc_doulongvec_minmax,
+ },
+ {
+ .procname = "6lowpanfrag_low_thresh",
+ .maxlen = sizeof(unsigned long),
+ .mode = 0644,
+ .proc_handler = proc_doulongvec_minmax,
+ },
+ {
+ .procname = "6lowpanfrag_time",
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_jiffies,
+ },
+ { }
+};
+
+/* secret interval has been deprecated */
+static int lowpan_frags_secret_interval_unused;
+static struct ctl_table lowpan_frags_ctl_table[] = {
+ {
+ .procname = "6lowpanfrag_secret_interval",
+ .data = &lowpan_frags_secret_interval_unused,
+ .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;
+ struct netns_ieee802154_lowpan *ieee802154_lowpan =
+ net_ieee802154_lowpan(net);
+ size_t table_size = ARRAY_SIZE(lowpan_frags_ns_ctl_table);
+
+ 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;
+
+ /* Don't export sysctls to unprivileged users */
+ if (net->user_ns != &init_user_ns) {
+ table[0].procname = NULL;
+ table_size = 0;
+ }
+ }
+
+ table[0].data = &ieee802154_lowpan->fqdir->high_thresh;
+ table[0].extra1 = &ieee802154_lowpan->fqdir->low_thresh;
+ table[1].data = &ieee802154_lowpan->fqdir->low_thresh;
+ table[1].extra2 = &ieee802154_lowpan->fqdir->high_thresh;
+ table[2].data = &ieee802154_lowpan->fqdir->timeout;
+
+ hdr = register_net_sysctl_sz(net, "net/ieee802154/6lowpan", table,
+ table_size);
+ if (hdr == NULL)
+ goto err_reg;
+
+ 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;
+ struct netns_ieee802154_lowpan *ieee802154_lowpan =
+ net_ieee802154_lowpan(net);
+
+ table = ieee802154_lowpan->sysctl.frags_hdr->ctl_table_arg;
+ unregister_net_sysctl_table(ieee802154_lowpan->sysctl.frags_hdr);
+ if (!net_eq(net, &init_net))
+ kfree(table);
+}
+
+static struct ctl_table_header *lowpan_ctl_header;
+
+static int __init 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 __init 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)
+{
+ struct netns_ieee802154_lowpan *ieee802154_lowpan =
+ net_ieee802154_lowpan(net);
+ int res;
+
+
+ res = fqdir_init(&ieee802154_lowpan->fqdir, &lowpan_frags, net);
+ if (res < 0)
+ return res;
+
+ ieee802154_lowpan->fqdir->high_thresh = IPV6_FRAG_HIGH_THRESH;
+ ieee802154_lowpan->fqdir->low_thresh = IPV6_FRAG_LOW_THRESH;
+ ieee802154_lowpan->fqdir->timeout = IPV6_FRAG_TIMEOUT;
+
+ res = lowpan_frags_ns_sysctl_register(net);
+ if (res < 0)
+ fqdir_exit(ieee802154_lowpan->fqdir);
+ return res;
+}
+
+static void __net_exit lowpan_frags_pre_exit_net(struct net *net)
+{
+ struct netns_ieee802154_lowpan *ieee802154_lowpan =
+ net_ieee802154_lowpan(net);
+
+ fqdir_pre_exit(ieee802154_lowpan->fqdir);
+}
+
+static void __net_exit lowpan_frags_exit_net(struct net *net)
+{
+ struct netns_ieee802154_lowpan *ieee802154_lowpan =
+ net_ieee802154_lowpan(net);
+
+ lowpan_frags_ns_sysctl_unregister(net);
+ fqdir_exit(ieee802154_lowpan->fqdir);
+}
+
+static struct pernet_operations lowpan_frags_ops = {
+ .init = lowpan_frags_init_net,
+ .pre_exit = lowpan_frags_pre_exit_net,
+ .exit = lowpan_frags_exit_net,
+};
+
+static u32 lowpan_key_hashfn(const void *data, u32 len, u32 seed)
+{
+ return jhash2(data,
+ sizeof(struct frag_lowpan_compare_key) / sizeof(u32), seed);
+}
+
+static u32 lowpan_obj_hashfn(const void *data, u32 len, u32 seed)
+{
+ const struct inet_frag_queue *fq = data;
+
+ return jhash2((const u32 *)&fq->key,
+ sizeof(struct frag_lowpan_compare_key) / sizeof(u32), seed);
+}
+
+static int lowpan_obj_cmpfn(struct rhashtable_compare_arg *arg, const void *ptr)
+{
+ const struct frag_lowpan_compare_key *key = arg->key;
+ const struct inet_frag_queue *fq = ptr;
+
+ return !!memcmp(&fq->key, key, sizeof(*key));
+}
+
+static const struct rhashtable_params lowpan_rhash_params = {
+ .head_offset = offsetof(struct inet_frag_queue, node),
+ .hashfn = lowpan_key_hashfn,
+ .obj_hashfn = lowpan_obj_hashfn,
+ .obj_cmpfn = lowpan_obj_cmpfn,
+ .automatic_shrinking = true,
+};
+
+int __init lowpan_net_frag_init(void)
+{
+ int ret;
+
+ lowpan_frags.constructor = lowpan_frag_init;
+ lowpan_frags.destructor = NULL;
+ lowpan_frags.qsize = sizeof(struct frag_queue);
+ lowpan_frags.frag_expire = lowpan_frag_expire;
+ lowpan_frags.frags_cache_name = lowpan_frags_cache_name;
+ lowpan_frags.rhash_params = lowpan_rhash_params;
+ ret = inet_frags_init(&lowpan_frags);
+ if (ret)
+ goto out;
+
+ ret = lowpan_frags_sysctl_register();
+ if (ret)
+ goto err_sysctl;
+
+ ret = register_pernet_subsys(&lowpan_frags_ops);
+ if (ret)
+ goto err_pernet;
+out:
+ return ret;
+err_pernet:
+ lowpan_frags_sysctl_unregister();
+err_sysctl:
+ inet_frags_fini(&lowpan_frags);
+ return ret;
+}
+
+void lowpan_net_frag_exit(void)
+{
+ lowpan_frags_sysctl_unregister();
+ unregister_pernet_subsys(&lowpan_frags_ops);
+ inet_frags_fini(&lowpan_frags);
+}