linux/net/6lowpan/nhc.c
Alexander Aring 607b0bd3f2 6lowpan: nhc: move iphc manipulation out of nhc
This patch moves the iphc setting of next header commpression bit inside
iphc functionality. Setting of IPHC bits should be happen at iphc.c file
only.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2015-10-21 00:49:25 +02:00

240 lines
5.3 KiB
C

/*
* 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];
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 = container_of(*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 = container_of(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);