linux/net/ieee802154/6lowpan.c
Alan Ott b333b7e6ec 6lowpan: consider checksum bytes in fragmentation threshold
Change the threshold for framentation of a lowpan packet from
using the MTU size to now use the MTU size minus the checksum length,
which is added by the hardware. For IEEE 802.15.4, this effectively
changes it from 127 bytes to 125 bytes.

Signed-off-by: Alan Ott <alan@signal11.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-11-30 12:19:24 -05:00

1322 lines
34 KiB
C

/*
* Copyright 2011, Siemens AG
* written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
*/
/*
* Based on patches from Jon Smirl <jonsmirl@gmail.com>
* Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/* Jon's code is based on 6lowpan implementation for Contiki which is:
* Copyright (c) 2008, Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <linux/bitops.h>
#include <linux/if_arp.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/netdevice.h>
#include <net/af_ieee802154.h>
#include <net/ieee802154.h>
#include <net/ieee802154_netdev.h>
#include <net/ipv6.h>
#include "6lowpan.h"
/* TTL uncompression values */
static const u8 lowpan_ttl_values[] = {0, 1, 64, 255};
static LIST_HEAD(lowpan_devices);
/*
* Uncompression of linklocal:
* 0 -> 16 bytes from packet
* 1 -> 2 bytes from prefix - bunch of zeroes and 8 from packet
* 2 -> 2 bytes from prefix - zeroes + 2 from packet
* 3 -> 2 bytes from prefix - infer 8 bytes from lladdr
*
* NOTE: => the uncompress function does change 0xf to 0x10
* NOTE: 0x00 => no-autoconfig => unspecified
*/
static const u8 lowpan_unc_llconf[] = {0x0f, 0x28, 0x22, 0x20};
/*
* Uncompression of ctx-based:
* 0 -> 0 bits from packet [unspecified / reserved]
* 1 -> 8 bytes from prefix - bunch of zeroes and 8 from packet
* 2 -> 8 bytes from prefix - zeroes + 2 from packet
* 3 -> 8 bytes from prefix - infer 8 bytes from lladdr
*/
static const u8 lowpan_unc_ctxconf[] = {0x00, 0x88, 0x82, 0x80};
/*
* Uncompression of ctx-base
* 0 -> 0 bits from packet
* 1 -> 2 bytes from prefix - bunch of zeroes 5 from packet
* 2 -> 2 bytes from prefix - zeroes + 3 from packet
* 3 -> 2 bytes from prefix - infer 1 bytes from lladdr
*/
static const u8 lowpan_unc_mxconf[] = {0x0f, 0x25, 0x23, 0x21};
/* Link local prefix */
static const u8 lowpan_llprefix[] = {0xfe, 0x80};
/* private device info */
struct lowpan_dev_info {
struct net_device *real_dev; /* real WPAN device ptr */
struct mutex dev_list_mtx; /* mutex for list ops */
};
struct lowpan_dev_record {
struct net_device *ldev;
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 unsigned short fragment_tag;
static LIST_HEAD(lowpan_fragments);
static DEFINE_SPINLOCK(flist_lock);
static inline struct
lowpan_dev_info *lowpan_dev_info(const struct net_device *dev)
{
return netdev_priv(dev);
}
static inline void lowpan_address_flip(u8 *src, u8 *dest)
{
int i;
for (i = 0; i < IEEE802154_ADDR_LEN; i++)
(dest)[IEEE802154_ADDR_LEN - i - 1] = (src)[i];
}
/* list of all 6lowpan devices, uses for package delivering */
/* print data in line */
static inline void lowpan_raw_dump_inline(const char *caller, char *msg,
unsigned char *buf, int len)
{
#ifdef DEBUG
if (msg)
pr_debug("(%s) %s: ", caller, msg);
print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE,
16, 1, buf, len, false);
#endif /* DEBUG */
}
/*
* print data in a table format:
*
* addr: xx xx xx xx xx xx
* addr: xx xx xx xx xx xx
* ...
*/
static inline void lowpan_raw_dump_table(const char *caller, char *msg,
unsigned char *buf, int len)
{
#ifdef DEBUG
if (msg)
pr_debug("(%s) %s:\n", caller, msg);
print_hex_dump(KERN_DEBUG, "\t", DUMP_PREFIX_OFFSET,
16, 1, buf, len, false);
#endif /* DEBUG */
}
static u8
lowpan_compress_addr_64(u8 **hc06_ptr, u8 shift, const struct in6_addr *ipaddr,
const unsigned char *lladdr)
{
u8 val = 0;
if (is_addr_mac_addr_based(ipaddr, lladdr))
val = 3; /* 0-bits */
else if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
/* compress IID to 16 bits xxxx::XXXX */
memcpy(*hc06_ptr, &ipaddr->s6_addr16[7], 2);
*hc06_ptr += 2;
val = 2; /* 16-bits */
} else {
/* do not compress IID => xxxx::IID */
memcpy(*hc06_ptr, &ipaddr->s6_addr16[4], 8);
*hc06_ptr += 8;
val = 1; /* 64-bits */
}
return rol8(val, shift);
}
static void
lowpan_uip_ds6_set_addr_iid(struct in6_addr *ipaddr, unsigned char *lladdr)
{
memcpy(&ipaddr->s6_addr[8], lladdr, IEEE802154_ADDR_LEN);
/* second bit-flip (Universe/Local) is done according RFC2464 */
ipaddr->s6_addr[8] ^= 0x02;
}
/*
* Uncompress addresses based on a prefix and a postfix with zeroes in
* between. If the postfix is zero in length it will use the link address
* to configure the IP address (autoconf style).
* pref_post_count takes a byte where the first nibble specify prefix count
* and the second postfix count (NOTE: 15/0xf => 16 bytes copy).
*/
static int
lowpan_uncompress_addr(struct sk_buff *skb, struct in6_addr *ipaddr,
u8 const *prefix, u8 pref_post_count, unsigned char *lladdr)
{
u8 prefcount = pref_post_count >> 4;
u8 postcount = pref_post_count & 0x0f;
/* full nibble 15 => 16 */
prefcount = (prefcount == 15 ? 16 : prefcount);
postcount = (postcount == 15 ? 16 : postcount);
if (lladdr)
lowpan_raw_dump_inline(__func__, "linklocal address",
lladdr, IEEE802154_ADDR_LEN);
if (prefcount > 0)
memcpy(ipaddr, prefix, prefcount);
if (prefcount + postcount < 16)
memset(&ipaddr->s6_addr[prefcount], 0,
16 - (prefcount + postcount));
if (postcount > 0) {
memcpy(&ipaddr->s6_addr[16 - postcount], skb->data, postcount);
skb_pull(skb, postcount);
} else if (prefcount > 0) {
if (lladdr == NULL)
return -EINVAL;
/* no IID based configuration if no prefix and no data */
lowpan_uip_ds6_set_addr_iid(ipaddr, lladdr);
}
pr_debug("uncompressing %d + %d => ", prefcount, postcount);
lowpan_raw_dump_inline(NULL, NULL, ipaddr->s6_addr, 16);
return 0;
}
static void
lowpan_compress_udp_header(u8 **hc06_ptr, struct sk_buff *skb)
{
struct udphdr *uh = udp_hdr(skb);
if (((uh->source & LOWPAN_NHC_UDP_4BIT_MASK) ==
LOWPAN_NHC_UDP_4BIT_PORT) &&
((uh->dest & LOWPAN_NHC_UDP_4BIT_MASK) ==
LOWPAN_NHC_UDP_4BIT_PORT)) {
pr_debug("UDP header: both ports compression to 4 bits\n");
**hc06_ptr = LOWPAN_NHC_UDP_CS_P_11;
**(hc06_ptr + 1) = /* subtraction is faster */
(u8)((uh->dest - LOWPAN_NHC_UDP_4BIT_PORT) +
((uh->source & LOWPAN_NHC_UDP_4BIT_PORT) << 4));
*hc06_ptr += 2;
} else if ((uh->dest & LOWPAN_NHC_UDP_8BIT_MASK) ==
LOWPAN_NHC_UDP_8BIT_PORT) {
pr_debug("UDP header: remove 8 bits of dest\n");
**hc06_ptr = LOWPAN_NHC_UDP_CS_P_01;
memcpy(*hc06_ptr + 1, &uh->source, 2);
**(hc06_ptr + 3) = (u8)(uh->dest - LOWPAN_NHC_UDP_8BIT_PORT);
*hc06_ptr += 4;
} else if ((uh->source & LOWPAN_NHC_UDP_8BIT_MASK) ==
LOWPAN_NHC_UDP_8BIT_PORT) {
pr_debug("UDP header: remove 8 bits of source\n");
**hc06_ptr = LOWPAN_NHC_UDP_CS_P_10;
memcpy(*hc06_ptr + 1, &uh->dest, 2);
**(hc06_ptr + 3) = (u8)(uh->source - LOWPAN_NHC_UDP_8BIT_PORT);
*hc06_ptr += 4;
} else {
pr_debug("UDP header: can't compress\n");
**hc06_ptr = LOWPAN_NHC_UDP_CS_P_00;
memcpy(*hc06_ptr + 1, &uh->source, 2);
memcpy(*hc06_ptr + 3, &uh->dest, 2);
*hc06_ptr += 5;
}
/* checksum is always inline */
memcpy(*hc06_ptr, &uh->check, 2);
*hc06_ptr += 2;
}
static inline int lowpan_fetch_skb_u8(struct sk_buff *skb, u8 *val)
{
if (unlikely(!pskb_may_pull(skb, 1)))
return -EINVAL;
*val = skb->data[0];
skb_pull(skb, 1);
return 0;
}
static inline int lowpan_fetch_skb_u16(struct sk_buff *skb, u16 *val)
{
if (unlikely(!pskb_may_pull(skb, 2)))
return -EINVAL;
*val = (skb->data[0] << 8) | skb->data[1];
skb_pull(skb, 2);
return 0;
}
static int
lowpan_uncompress_udp_header(struct sk_buff *skb)
{
struct udphdr *uh = udp_hdr(skb);
u8 tmp;
if (!uh)
goto err;
if (lowpan_fetch_skb_u8(skb, &tmp))
goto err;
if ((tmp & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) {
pr_debug("UDP header uncompression\n");
switch (tmp & LOWPAN_NHC_UDP_CS_P_11) {
case LOWPAN_NHC_UDP_CS_P_00:
memcpy(&uh->source, &skb->data[0], 2);
memcpy(&uh->dest, &skb->data[2], 2);
skb_pull(skb, 4);
break;
case LOWPAN_NHC_UDP_CS_P_01:
memcpy(&uh->source, &skb->data[0], 2);
uh->dest =
skb->data[2] + LOWPAN_NHC_UDP_8BIT_PORT;
skb_pull(skb, 3);
break;
case LOWPAN_NHC_UDP_CS_P_10:
uh->source = skb->data[0] + LOWPAN_NHC_UDP_8BIT_PORT;
memcpy(&uh->dest, &skb->data[1], 2);
skb_pull(skb, 3);
break;
case LOWPAN_NHC_UDP_CS_P_11:
uh->source =
LOWPAN_NHC_UDP_4BIT_PORT + (skb->data[0] >> 4);
uh->dest =
LOWPAN_NHC_UDP_4BIT_PORT + (skb->data[0] & 0x0f);
skb_pull(skb, 1);
break;
default:
pr_debug("ERROR: unknown UDP format\n");
goto err;
break;
}
pr_debug("uncompressed UDP ports: src = %d, dst = %d\n",
uh->source, uh->dest);
/* copy checksum */
memcpy(&uh->check, &skb->data[0], 2);
skb_pull(skb, 2);
} else {
pr_debug("ERROR: unsupported NH format\n");
goto err;
}
return 0;
err:
return -EINVAL;
}
static int lowpan_header_create(struct sk_buff *skb,
struct net_device *dev,
unsigned short type, const void *_daddr,
const void *_saddr, unsigned int len)
{
u8 tmp, iphc0, iphc1, *hc06_ptr;
struct ipv6hdr *hdr;
const u8 *saddr = _saddr;
const u8 *daddr = _daddr;
u8 *head;
struct ieee802154_addr sa, da;
if (type != ETH_P_IPV6)
return 0;
/* TODO:
* if this package isn't ipv6 one, where should it be routed?
*/
head = kzalloc(100, GFP_KERNEL);
if (head == NULL)
return -ENOMEM;
hdr = ipv6_hdr(skb);
hc06_ptr = head + 2;
pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n"
"\tnexthdr = 0x%02x\n\thop_lim = %d\n", hdr->version,
ntohs(hdr->payload_len), hdr->nexthdr, hdr->hop_limit);
lowpan_raw_dump_table(__func__, "raw skb network header dump",
skb_network_header(skb), sizeof(struct ipv6hdr));
if (!saddr)
saddr = dev->dev_addr;
lowpan_raw_dump_inline(__func__, "saddr", (unsigned char *)saddr, 8);
/*
* As we copy some bit-length fields, in the IPHC encoding bytes,
* we sometimes use |=
* If the field is 0, and the current bit value in memory is 1,
* this does not work. We therefore reset the IPHC encoding here
*/
iphc0 = LOWPAN_DISPATCH_IPHC;
iphc1 = 0;
/* TODO: context lookup */
lowpan_raw_dump_inline(__func__, "daddr", (unsigned char *)daddr, 8);
/*
* Traffic class, flow label
* If flow label is 0, compress it. If traffic class is 0, compress it
* We have to process both in the same time as the offset of traffic
* class depends on the presence of version and flow label
*/
/* hc06 format of TC is ECN | DSCP , original one is DSCP | ECN */
tmp = (hdr->priority << 4) | (hdr->flow_lbl[0] >> 4);
tmp = ((tmp & 0x03) << 6) | (tmp >> 2);
if (((hdr->flow_lbl[0] & 0x0F) == 0) &&
(hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) {
/* flow label can be compressed */
iphc0 |= LOWPAN_IPHC_FL_C;
if ((hdr->priority == 0) &&
((hdr->flow_lbl[0] & 0xF0) == 0)) {
/* compress (elide) all */
iphc0 |= LOWPAN_IPHC_TC_C;
} else {
/* compress only the flow label */
*hc06_ptr = tmp;
hc06_ptr += 1;
}
} else {
/* Flow label cannot be compressed */
if ((hdr->priority == 0) &&
((hdr->flow_lbl[0] & 0xF0) == 0)) {
/* compress only traffic class */
iphc0 |= LOWPAN_IPHC_TC_C;
*hc06_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F);
memcpy(hc06_ptr + 1, &hdr->flow_lbl[1], 2);
hc06_ptr += 3;
} else {
/* compress nothing */
memcpy(hc06_ptr, &hdr, 4);
/* replace the top byte with new ECN | DSCP format */
*hc06_ptr = tmp;
hc06_ptr += 4;
}
}
/* NOTE: payload length is always compressed */
/* Next Header is compress if UDP */
if (hdr->nexthdr == UIP_PROTO_UDP)
iphc0 |= LOWPAN_IPHC_NH_C;
if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
*hc06_ptr = hdr->nexthdr;
hc06_ptr += 1;
}
/*
* Hop limit
* if 1: compress, encoding is 01
* if 64: compress, encoding is 10
* if 255: compress, encoding is 11
* else do not compress
*/
switch (hdr->hop_limit) {
case 1:
iphc0 |= LOWPAN_IPHC_TTL_1;
break;
case 64:
iphc0 |= LOWPAN_IPHC_TTL_64;
break;
case 255:
iphc0 |= LOWPAN_IPHC_TTL_255;
break;
default:
*hc06_ptr = hdr->hop_limit;
hc06_ptr += 1;
break;
}
/* source address compression */
if (is_addr_unspecified(&hdr->saddr)) {
pr_debug("source address is unspecified, setting SAC\n");
iphc1 |= LOWPAN_IPHC_SAC;
/* TODO: context lookup */
} else if (is_addr_link_local(&hdr->saddr)) {
pr_debug("source address is link-local\n");
iphc1 |= lowpan_compress_addr_64(&hc06_ptr,
LOWPAN_IPHC_SAM_BIT, &hdr->saddr, saddr);
} else {
pr_debug("send the full source address\n");
memcpy(hc06_ptr, &hdr->saddr.s6_addr16[0], 16);
hc06_ptr += 16;
}
/* destination address compression */
if (is_addr_mcast(&hdr->daddr)) {
pr_debug("destination address is multicast: ");
iphc1 |= LOWPAN_IPHC_M;
if (lowpan_is_mcast_addr_compressable8(&hdr->daddr)) {
pr_debug("compressed to 1 octet\n");
iphc1 |= LOWPAN_IPHC_DAM_11;
/* use last byte */
*hc06_ptr = hdr->daddr.s6_addr[15];
hc06_ptr += 1;
} else if (lowpan_is_mcast_addr_compressable32(&hdr->daddr)) {
pr_debug("compressed to 4 octets\n");
iphc1 |= LOWPAN_IPHC_DAM_10;
/* second byte + the last three */
*hc06_ptr = hdr->daddr.s6_addr[1];
memcpy(hc06_ptr + 1, &hdr->daddr.s6_addr[13], 3);
hc06_ptr += 4;
} else if (lowpan_is_mcast_addr_compressable48(&hdr->daddr)) {
pr_debug("compressed to 6 octets\n");
iphc1 |= LOWPAN_IPHC_DAM_01;
/* second byte + the last five */
*hc06_ptr = hdr->daddr.s6_addr[1];
memcpy(hc06_ptr + 1, &hdr->daddr.s6_addr[11], 5);
hc06_ptr += 6;
} else {
pr_debug("using full address\n");
iphc1 |= LOWPAN_IPHC_DAM_00;
memcpy(hc06_ptr, &hdr->daddr.s6_addr[0], 16);
hc06_ptr += 16;
}
} else {
/* TODO: context lookup */
if (is_addr_link_local(&hdr->daddr)) {
pr_debug("dest address is unicast and link-local\n");
iphc1 |= lowpan_compress_addr_64(&hc06_ptr,
LOWPAN_IPHC_DAM_BIT, &hdr->daddr, daddr);
} else {
pr_debug("dest address is unicast: using full one\n");
memcpy(hc06_ptr, &hdr->daddr.s6_addr16[0], 16);
hc06_ptr += 16;
}
}
/* UDP header compression */
if (hdr->nexthdr == UIP_PROTO_UDP)
lowpan_compress_udp_header(&hc06_ptr, skb);
head[0] = iphc0;
head[1] = iphc1;
skb_pull(skb, sizeof(struct ipv6hdr));
memcpy(skb_push(skb, hc06_ptr - head), head, hc06_ptr - head);
kfree(head);
lowpan_raw_dump_table(__func__, "raw skb data dump", skb->data,
skb->len);
/*
* NOTE1: I'm still unsure about the fact that compression and WPAN
* header are created here and not later in the xmit. So wait for
* an opinion of net maintainers.
*/
/*
* NOTE2: to be absolutely correct, we must derive PANid information
* from MAC subif of the 'dev' and 'real_dev' network devices, but
* this isn't implemented in mainline yet, so currently we assign 0xff
*/
{
/* prepare wpan address data */
sa.addr_type = IEEE802154_ADDR_LONG;
sa.pan_id = 0xff;
da.addr_type = IEEE802154_ADDR_LONG;
da.pan_id = 0xff;
memcpy(&(da.hwaddr), daddr, 8);
memcpy(&(sa.hwaddr), saddr, 8);
mac_cb(skb)->flags = IEEE802154_FC_TYPE_DATA;
return dev_hard_header(skb, lowpan_dev_info(dev)->real_dev,
type, (void *)&da, (void *)&sa, skb->len);
}
}
static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
{
struct sk_buff *new;
struct lowpan_dev_record *entry;
int stat = NET_RX_SUCCESS;
new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
GFP_ATOMIC);
kfree_skb(skb);
if (!new)
return -ENOMEM;
skb_push(new, sizeof(struct ipv6hdr));
skb_reset_network_header(new);
skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
new->protocol = htons(ETH_P_IPV6);
new->pkt_type = PACKET_HOST;
rcu_read_lock();
list_for_each_entry_rcu(entry, &lowpan_devices, list)
if (lowpan_dev_info(entry->ldev)->real_dev == new->dev) {
skb = skb_copy(new, GFP_ATOMIC);
if (!skb) {
stat = -ENOMEM;
break;
}
skb->dev = entry->ldev;
stat = netif_rx(skb);
}
rcu_read_unlock();
kfree_skb(new);
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, u8 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;
frame->skb->dev = skb->dev;
/* reserve headroom for uncompressed ipv6 header */
skb_reserve(frame->skb, sizeof(struct ipv6hdr));
skb_put(frame->skb, frame->length);
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
lowpan_process_data(struct sk_buff *skb)
{
struct ipv6hdr hdr;
u8 tmp, iphc0, iphc1, num_context = 0;
u8 *_saddr, *_daddr;
int err;
lowpan_raw_dump_table(__func__, "raw skb data dump", skb->data,
skb->len);
/* at least two bytes will be used for the encoding */
if (skb->len < 2)
goto drop;
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;
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;
/*
* 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) {
frame = lowpan_alloc_new_frame(skb, len, tag);
if (!frame)
goto unlock_and_drop;
}
if ((iphc0 & LOWPAN_DISPATCH_MASK) == LOWPAN_DISPATCH_FRAG1)
goto unlock_and_drop;
if (lowpan_fetch_skb_u8(skb, &offset)) /* fetch offset */
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);
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;
_saddr = mac_cb(skb)->sa.hwaddr;
_daddr = mac_cb(skb)->da.hwaddr;
pr_debug("iphc0 = %02x, iphc1 = %02x\n", iphc0, iphc1);
/* another if the CID flag is set */
if (iphc1 & LOWPAN_IPHC_CID) {
pr_debug("CID flag is set, increase header with one\n");
if (lowpan_fetch_skb_u8(skb, &num_context))
goto drop;
}
hdr.version = 6;
/* Traffic Class and Flow Label */
switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) {
/*
* Traffic Class and FLow Label carried in-line
* ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
*/
case 0: /* 00b */
if (lowpan_fetch_skb_u8(skb, &tmp))
goto drop;
memcpy(&hdr.flow_lbl, &skb->data[0], 3);
skb_pull(skb, 3);
hdr.priority = ((tmp >> 2) & 0x0f);
hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) | (tmp << 6) |
(hdr.flow_lbl[0] & 0x0f);
break;
/*
* Traffic class carried in-line
* ECN + DSCP (1 byte), Flow Label is elided
*/
case 1: /* 10b */
if (lowpan_fetch_skb_u8(skb, &tmp))
goto drop;
hdr.priority = ((tmp >> 2) & 0x0f);
hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
hdr.flow_lbl[1] = 0;
hdr.flow_lbl[2] = 0;
break;
/*
* Flow Label carried in-line
* ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
*/
case 2: /* 01b */
if (lowpan_fetch_skb_u8(skb, &tmp))
goto drop;
hdr.flow_lbl[0] = (skb->data[0] & 0x0F) | ((tmp >> 2) & 0x30);
memcpy(&hdr.flow_lbl[1], &skb->data[0], 2);
skb_pull(skb, 2);
break;
/* Traffic Class and Flow Label are elided */
case 3: /* 11b */
hdr.priority = 0;
hdr.flow_lbl[0] = 0;
hdr.flow_lbl[1] = 0;
hdr.flow_lbl[2] = 0;
break;
default:
break;
}
/* Next Header */
if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
/* Next header is carried inline */
if (lowpan_fetch_skb_u8(skb, &(hdr.nexthdr)))
goto drop;
pr_debug("NH flag is set, next header carried inline: %02x\n",
hdr.nexthdr);
}
/* Hop Limit */
if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I)
hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03];
else {
if (lowpan_fetch_skb_u8(skb, &(hdr.hop_limit)))
goto drop;
}
/* Extract SAM to the tmp variable */
tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03;
/* Source address uncompression */
pr_debug("source address stateless compression\n");
err = lowpan_uncompress_addr(skb, &hdr.saddr, lowpan_llprefix,
lowpan_unc_llconf[tmp], skb->data);
if (err)
goto drop;
/* Extract DAM to the tmp variable */
tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03;
/* check for Multicast Compression */
if (iphc1 & LOWPAN_IPHC_M) {
if (iphc1 & LOWPAN_IPHC_DAC) {
pr_debug("dest: context-based mcast compression\n");
/* TODO: implement this */
} else {
u8 prefix[] = {0xff, 0x02};
pr_debug("dest: non context-based mcast compression\n");
if (0 < tmp && tmp < 3) {
if (lowpan_fetch_skb_u8(skb, &prefix[1]))
goto drop;
}
err = lowpan_uncompress_addr(skb, &hdr.daddr, prefix,
lowpan_unc_mxconf[tmp], NULL);
if (err)
goto drop;
}
} else {
pr_debug("dest: stateless compression\n");
err = lowpan_uncompress_addr(skb, &hdr.daddr, lowpan_llprefix,
lowpan_unc_llconf[tmp], skb->data);
if (err)
goto drop;
}
/* UDP data uncompression */
if (iphc0 & LOWPAN_IPHC_NH_C)
if (lowpan_uncompress_udp_header(skb))
goto drop;
/* Not fragmented package */
hdr.payload_len = htons(skb->len);
pr_debug("skb headroom size = %d, data length = %d\n",
skb_headroom(skb), skb->len);
pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n\t"
"nexthdr = 0x%02x\n\thop_lim = %d\n", hdr.version,
ntohs(hdr.payload_len), hdr.nexthdr, hdr.hop_limit);
lowpan_raw_dump_table(__func__, "raw header dump", (u8 *)&hdr,
sizeof(hdr));
return lowpan_skb_deliver(skb, &hdr);
unlock_and_drop:
spin_unlock_bh(&flist_lock);
drop:
kfree_skb(skb);
return -EINVAL;
}
static int lowpan_set_address(struct net_device *dev, void *p)
{
struct sockaddr *sa = p;
if (netif_running(dev))
return -EBUSY;
/* TODO: validate addr */
memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
return 0;
}
static int lowpan_get_mac_header_length(struct sk_buff *skb)
{
/*
* Currently long addressing mode is supported only, so the overall
* header size is 21:
* FC SeqNum DPAN DA SA Sec
* 2 + 1 + 2 + 8 + 8 + 0 = 21
*/
return 21;
}
static int
lowpan_fragment_xmit(struct sk_buff *skb, u8 *head,
int mlen, int plen, int offset)
{
struct sk_buff *frag;
int hlen, ret;
/* if payload length is zero, therefore it's a first fragment */
hlen = (plen == 0 ? LOWPAN_FRAG1_HEAD_SIZE : LOWPAN_FRAGN_HEAD_SIZE);
lowpan_raw_dump_inline(__func__, "6lowpan fragment header", head, hlen);
frag = dev_alloc_skb(hlen + mlen + plen + IEEE802154_MFR_SIZE);
if (!frag)
return -ENOMEM;
frag->priority = skb->priority;
frag->dev = skb->dev;
/* copy header, MFR and payload */
memcpy(skb_put(frag, mlen), skb->data, mlen);
memcpy(skb_put(frag, hlen), head, hlen);
if (plen)
skb_copy_from_linear_data_offset(skb, offset + mlen,
skb_put(frag, plen), plen);
lowpan_raw_dump_table(__func__, " raw fragment dump", frag->data,
frag->len);
ret = dev_queue_xmit(frag);
return ret;
}
static int
lowpan_skb_fragmentation(struct sk_buff *skb)
{
int err, header_length, payload_length, tag, offset = 0;
u8 head[5];
header_length = lowpan_get_mac_header_length(skb);
payload_length = skb->len - header_length;
tag = fragment_tag++;
/* first fragment header */
head[0] = LOWPAN_DISPATCH_FRAG1 | ((payload_length >> 8) & 0x7);
head[1] = payload_length & 0xff;
head[2] = tag >> 8;
head[3] = tag & 0xff;
err = lowpan_fragment_xmit(skb, head, header_length, 0, 0);
/* next fragment header */
head[0] &= ~LOWPAN_DISPATCH_FRAG1;
head[0] |= LOWPAN_DISPATCH_FRAGN;
while ((payload_length - offset > 0) && (err >= 0)) {
int len = LOWPAN_FRAG_SIZE;
head[4] = offset / 8;
if (payload_length - offset < len)
len = payload_length - offset;
err = lowpan_fragment_xmit(skb, head, header_length,
len, offset);
offset += len;
}
return err;
}
static netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *dev)
{
int err = -1;
pr_debug("package xmit\n");
skb->dev = lowpan_dev_info(dev)->real_dev;
if (skb->dev == NULL) {
pr_debug("ERROR: no real wpan device found\n");
goto error;
}
/* Send directly if less than the MTU minus the 2 checksum bytes. */
if (skb->len <= IEEE802154_MTU - IEEE802154_MFR_SIZE) {
err = dev_queue_xmit(skb);
goto out;
}
pr_debug("frame is too big, fragmentation is needed\n");
err = lowpan_skb_fragmentation(skb);
error:
dev_kfree_skb(skb);
out:
if (err < 0)
pr_debug("ERROR: xmit failed\n");
return (err < 0 ? NETDEV_TX_BUSY : NETDEV_TX_OK);
}
static struct wpan_phy *lowpan_get_phy(const struct net_device *dev)
{
struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
return ieee802154_mlme_ops(real_dev)->get_phy(real_dev);
}
static u16 lowpan_get_pan_id(const struct net_device *dev)
{
struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
return ieee802154_mlme_ops(real_dev)->get_pan_id(real_dev);
}
static u16 lowpan_get_short_addr(const struct net_device *dev)
{
struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
return ieee802154_mlme_ops(real_dev)->get_short_addr(real_dev);
}
static struct header_ops lowpan_header_ops = {
.create = lowpan_header_create,
};
static const struct net_device_ops lowpan_netdev_ops = {
.ndo_start_xmit = lowpan_xmit,
.ndo_set_mac_address = lowpan_set_address,
};
static struct ieee802154_mlme_ops lowpan_mlme = {
.get_pan_id = lowpan_get_pan_id,
.get_phy = lowpan_get_phy,
.get_short_addr = lowpan_get_short_addr,
};
static void lowpan_setup(struct net_device *dev)
{
dev->addr_len = IEEE802154_ADDR_LEN;
memset(dev->broadcast, 0xff, IEEE802154_ADDR_LEN);
dev->type = ARPHRD_IEEE802154;
/* Frame Control + Sequence Number + Address fields + Security Header */
dev->hard_header_len = 2 + 1 + 20 + 14;
dev->needed_tailroom = 2; /* FCS */
dev->mtu = 1281;
dev->tx_queue_len = 0;
dev->flags = IFF_BROADCAST | IFF_MULTICAST;
dev->watchdog_timeo = 0;
dev->netdev_ops = &lowpan_netdev_ops;
dev->header_ops = &lowpan_header_ops;
dev->ml_priv = &lowpan_mlme;
dev->destructor = free_netdev;
}
static int lowpan_validate(struct nlattr *tb[], struct nlattr *data[])
{
if (tb[IFLA_ADDRESS]) {
if (nla_len(tb[IFLA_ADDRESS]) != IEEE802154_ADDR_LEN)
return -EINVAL;
}
return 0;
}
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;
if (!netif_running(dev))
goto drop;
if (dev->type != ARPHRD_IEEE802154)
goto drop;
/* check that it's our buffer */
switch (skb->data[0] & 0xe0) {
case LOWPAN_DISPATCH_IPHC: /* ipv6 datagram */
case LOWPAN_DISPATCH_FRAG1: /* first fragment header */
case LOWPAN_DISPATCH_FRAGN: /* next fragments headers */
local_skb = skb_clone(skb, GFP_ATOMIC);
if (!local_skb)
goto drop;
lowpan_process_data(local_skb);
kfree_skb(skb);
break;
default:
break;
}
return NET_RX_SUCCESS;
drop:
kfree_skb(skb);
return NET_RX_DROP;
}
static int lowpan_newlink(struct net *src_net, struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[])
{
struct net_device *real_dev;
struct lowpan_dev_record *entry;
pr_debug("adding new link\n");
if (!tb[IFLA_LINK])
return -EINVAL;
/* find and hold real wpan device */
real_dev = dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
if (!real_dev)
return -ENODEV;
lowpan_dev_info(dev)->real_dev = real_dev;
mutex_init(&lowpan_dev_info(dev)->dev_list_mtx);
entry = kzalloc(sizeof(struct lowpan_dev_record), GFP_KERNEL);
if (!entry) {
dev_put(real_dev);
lowpan_dev_info(dev)->real_dev = NULL;
return -ENOMEM;
}
entry->ldev = dev;
mutex_lock(&lowpan_dev_info(dev)->dev_list_mtx);
INIT_LIST_HEAD(&entry->list);
list_add_tail(&entry->list, &lowpan_devices);
mutex_unlock(&lowpan_dev_info(dev)->dev_list_mtx);
register_netdevice(dev);
return 0;
}
static void lowpan_dellink(struct net_device *dev, struct list_head *head)
{
struct lowpan_dev_info *lowpan_dev = lowpan_dev_info(dev);
struct net_device *real_dev = lowpan_dev->real_dev;
struct lowpan_dev_record *entry, *tmp;
ASSERT_RTNL();
mutex_lock(&lowpan_dev_info(dev)->dev_list_mtx);
list_for_each_entry_safe(entry, tmp, &lowpan_devices, list) {
if (entry->ldev == dev) {
list_del(&entry->list);
kfree(entry);
}
}
mutex_unlock(&lowpan_dev_info(dev)->dev_list_mtx);
mutex_destroy(&lowpan_dev_info(dev)->dev_list_mtx);
unregister_netdevice_queue(dev, head);
dev_put(real_dev);
}
static struct rtnl_link_ops lowpan_link_ops __read_mostly = {
.kind = "lowpan",
.priv_size = sizeof(struct lowpan_dev_info),
.setup = lowpan_setup,
.newlink = lowpan_newlink,
.dellink = lowpan_dellink,
.validate = lowpan_validate,
};
static inline int __init lowpan_netlink_init(void)
{
return rtnl_link_register(&lowpan_link_ops);
}
static inline void __init lowpan_netlink_fini(void)
{
rtnl_link_unregister(&lowpan_link_ops);
}
static int lowpan_device_event(struct notifier_block *unused,
unsigned long event,
void *ptr)
{
struct net_device *dev = ptr;
LIST_HEAD(del_list);
struct lowpan_dev_record *entry, *tmp;
if (dev->type != ARPHRD_IEEE802154)
goto out;
if (event == NETDEV_UNREGISTER) {
list_for_each_entry_safe(entry, tmp, &lowpan_devices, list) {
if (lowpan_dev_info(entry->ldev)->real_dev == dev)
lowpan_dellink(entry->ldev, &del_list);
}
unregister_netdevice_many(&del_list);
}
out:
return NOTIFY_DONE;
}
static struct notifier_block lowpan_dev_notifier = {
.notifier_call = lowpan_device_event,
};
static struct packet_type lowpan_packet_type = {
.type = __constant_htons(ETH_P_IEEE802154),
.func = lowpan_rcv,
};
static int __init lowpan_init_module(void)
{
int err = 0;
err = lowpan_netlink_init();
if (err < 0)
goto out;
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();
}
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);
/* 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);
}
module_init(lowpan_init_module);
module_exit(lowpan_cleanup_module);
MODULE_LICENSE("GPL");
MODULE_ALIAS_RTNL_LINK("lowpan");