diff options
Diffstat (limited to 'net/6lowpan/nhc.c')
| -rw-r--r-- | net/6lowpan/nhc.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/net/6lowpan/nhc.c b/net/6lowpan/nhc.c new file mode 100644 index 000000000..9e56fb98f --- /dev/null +++ b/net/6lowpan/nhc.c @@ -0,0 +1,239 @@ +/* + * 6LoWPAN next header compression + * + * + * Authors: + * Alexander Aring <aar@pengutronix.de> + * + * 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. + */ + +#include <linux/netdevice.h> + +#include <net/ipv6.h> + +#include "nhc.h" + +static struct rb_root rb_root = RB_ROOT; +static struct lowpan_nhc *lowpan_nexthdr_nhcs[NEXTHDR_MAX + 1]; +static DEFINE_SPINLOCK(lowpan_nhc_lock); + +static int lowpan_nhc_insert(struct lowpan_nhc *nhc) +{ + struct rb_node **new = &rb_root.rb_node, *parent = NULL; + + /* Figure out where to put new node */ + while (*new) { + struct lowpan_nhc *this = rb_entry(*new, struct lowpan_nhc, + node); + int result, len_dif, len; + + len_dif = nhc->idlen - this->idlen; + + if (nhc->idlen < this->idlen) + len = nhc->idlen; + else + len = this->idlen; + + result = memcmp(nhc->id, this->id, len); + if (!result) + result = len_dif; + + parent = *new; + if (result < 0) + new = &((*new)->rb_left); + else if (result > 0) + new = &((*new)->rb_right); + else + return -EEXIST; + } + + /* Add new node and rebalance tree. */ + rb_link_node(&nhc->node, parent, new); + rb_insert_color(&nhc->node, &rb_root); + + return 0; +} + +static void lowpan_nhc_remove(struct lowpan_nhc *nhc) +{ + rb_erase(&nhc->node, &rb_root); +} + +static struct lowpan_nhc *lowpan_nhc_by_nhcid(const struct sk_buff *skb) +{ + struct rb_node *node = rb_root.rb_node; + const u8 *nhcid_skb_ptr = skb->data; + + while (node) { + struct lowpan_nhc *nhc = rb_entry(node, struct lowpan_nhc, + node); + u8 nhcid_skb_ptr_masked[LOWPAN_NHC_MAX_ID_LEN]; + int result, i; + + if (nhcid_skb_ptr + nhc->idlen > skb->data + skb->len) + return NULL; + + /* copy and mask afterwards the nhid value from skb */ + memcpy(nhcid_skb_ptr_masked, nhcid_skb_ptr, nhc->idlen); + for (i = 0; i < nhc->idlen; i++) + nhcid_skb_ptr_masked[i] &= nhc->idmask[i]; + + result = memcmp(nhcid_skb_ptr_masked, nhc->id, nhc->idlen); + if (result < 0) + node = node->rb_left; + else if (result > 0) + node = node->rb_right; + else + return nhc; + } + + return NULL; +} + +int lowpan_nhc_check_compression(struct sk_buff *skb, + const struct ipv6hdr *hdr, u8 **hc_ptr) +{ + struct lowpan_nhc *nhc; + int ret = 0; + + spin_lock_bh(&lowpan_nhc_lock); + + nhc = lowpan_nexthdr_nhcs[hdr->nexthdr]; + if (!(nhc && nhc->compress)) + ret = -ENOENT; + + spin_unlock_bh(&lowpan_nhc_lock); + + return ret; +} + +int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr, + u8 **hc_ptr) +{ + int ret; + struct lowpan_nhc *nhc; + + spin_lock_bh(&lowpan_nhc_lock); + + nhc = lowpan_nexthdr_nhcs[hdr->nexthdr]; + /* check if the nhc module was removed in unlocked part. + * TODO: this is a workaround we should prevent unloading + * of nhc modules while unlocked part, this will always drop + * the lowpan packet but it's very unlikely. + * + * Solution isn't easy because we need to decide at + * lowpan_nhc_check_compression if we do a compression or not. + * Because the inline data which is added to skb, we can't move this + * handling. + */ + if (unlikely(!nhc || !nhc->compress)) { + ret = -EINVAL; + goto out; + } + + /* In the case of RAW sockets the transport header is not set by + * the ip6 stack so we must set it ourselves + */ + if (skb->transport_header == skb->network_header) + skb_set_transport_header(skb, sizeof(struct ipv6hdr)); + + ret = nhc->compress(skb, hc_ptr); + if (ret < 0) + goto out; + + /* skip the transport header */ + skb_pull(skb, nhc->nexthdrlen); + +out: + spin_unlock_bh(&lowpan_nhc_lock); + + return ret; +} + +int lowpan_nhc_do_uncompression(struct sk_buff *skb, + const struct net_device *dev, + struct ipv6hdr *hdr) +{ + struct lowpan_nhc *nhc; + int ret; + + spin_lock_bh(&lowpan_nhc_lock); + + nhc = lowpan_nhc_by_nhcid(skb); + if (nhc) { + if (nhc->uncompress) { + ret = nhc->uncompress(skb, sizeof(struct ipv6hdr) + + nhc->nexthdrlen); + if (ret < 0) { + spin_unlock_bh(&lowpan_nhc_lock); + return ret; + } + } else { + spin_unlock_bh(&lowpan_nhc_lock); + netdev_warn(dev, "received nhc id for %s which is not implemented.\n", + nhc->name); + return -ENOTSUPP; + } + } else { + spin_unlock_bh(&lowpan_nhc_lock); + netdev_warn(dev, "received unknown nhc id which was not found.\n"); + return -ENOENT; + } + + hdr->nexthdr = nhc->nexthdr; + skb_reset_transport_header(skb); + raw_dump_table(__func__, "raw transport header dump", + skb_transport_header(skb), nhc->nexthdrlen); + + spin_unlock_bh(&lowpan_nhc_lock); + + return 0; +} + +int lowpan_nhc_add(struct lowpan_nhc *nhc) +{ + int ret; + + if (!nhc->idlen || !nhc->idsetup) + return -EINVAL; + + WARN_ONCE(nhc->idlen > LOWPAN_NHC_MAX_ID_LEN, + "LOWPAN_NHC_MAX_ID_LEN should be updated to %zd.\n", + nhc->idlen); + + nhc->idsetup(nhc); + + spin_lock_bh(&lowpan_nhc_lock); + + if (lowpan_nexthdr_nhcs[nhc->nexthdr]) { + ret = -EEXIST; + goto out; + } + + ret = lowpan_nhc_insert(nhc); + if (ret < 0) + goto out; + + lowpan_nexthdr_nhcs[nhc->nexthdr] = nhc; +out: + spin_unlock_bh(&lowpan_nhc_lock); + return ret; +} +EXPORT_SYMBOL(lowpan_nhc_add); + +void lowpan_nhc_del(struct lowpan_nhc *nhc) +{ + spin_lock_bh(&lowpan_nhc_lock); + + lowpan_nhc_remove(nhc); + lowpan_nexthdr_nhcs[nhc->nexthdr] = NULL; + + spin_unlock_bh(&lowpan_nhc_lock); + + synchronize_net(); +} +EXPORT_SYMBOL(lowpan_nhc_del); |