linux/net/6lowpan/nhc.c
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00

235 lines
5.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 6LoWPAN next header compression
*
* Authors:
* Alexander Aring <aar@pengutronix.de>
*/
#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);