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linux/net/ieee802154/6lowpan.c

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/*
* 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");
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