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ieee820154: 6lowpan: dispatch evaluation rework 

This patch complete reworks the evaluation of 6lowpan dispatch value by
introducing a receive handler mechanism for each dispatch value.

A list of changes:

 - Doing uncompression on-the-fly when FRAG1 is received, this require
   some special handling for 802.15.4 lltype in generic 6lowpan branch
   for setting the payload length correct.
 - Fix dispatch mask for fragmentation.
 - Add IPv6 dispatch evaluation for FRAG1.
 - Add skb_unshare for dispatch which might manipulate the skb data
   buffer.

Cc: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Alexander Aring 2015-09-02 14:21:25 +02:00 committed by Marcel Holtmann
parent f801cf4024
commit 72a5e6bb51
6 changed files with 288 additions and 111 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
include/net/6lowpan.h
View File

@ -126,13 +126,19 @@
(((a)[6]) == 0xFF) && \
(((a)[7]) == 0xFF))
#define LOWPAN_DISPATCH_IPV6 0x41 /* 01000001 = 65 */
#define LOWPAN_DISPATCH_HC1 0x42 /* 01000010 = 66 */
#define LOWPAN_DISPATCH_IPHC 0x60 /* 011xxxxx = ... */
#define LOWPAN_DISPATCH_FRAG1 0xc0 /* 11000xxx */
#define LOWPAN_DISPATCH_FRAGN 0xe0 /* 11100xxx */
#define LOWPAN_DISPATCH_IPV6 0x41 /* 01000001 = 65 */
#define LOWPAN_DISPATCH_IPHC 0x60 /* 011xxxxx = ... */
#define LOWPAN_DISPATCH_IPHC_MASK 0xe0
#define LOWPAN_DISPATCH_MASK 0xf8 /* 11111000 */
static inline bool lowpan_is_ipv6(u8 dispatch)
{
return dispatch == LOWPAN_DISPATCH_IPV6;
}
static inline bool lowpan_is_iphc(u8 dispatch)
{
return (dispatch & LOWPAN_DISPATCH_IPHC_MASK) == LOWPAN_DISPATCH_IPHC;
}
#define LOWPAN_FRAG_TIMEOUT (HZ * 60) /* time-out 60 sec */
@ -218,6 +224,19 @@ struct lowpan_priv *lowpan_priv(const struct net_device *dev)
return netdev_priv(dev);
}
struct lowpan_802154_cb {
u16 d_tag;
unsigned int d_size;
u8 d_offset;
};
static inline
struct lowpan_802154_cb *lowpan_802154_cb(const struct sk_buff *skb)
{
BUILD_BUG_ON(sizeof(struct lowpan_802154_cb) > sizeof(skb->cb));
return (struct lowpan_802154_cb *)skb->cb;
}
#ifdef DEBUG
/* print data in line */
static inline void raw_dump_inline(const char *caller, char *msg,

13
net/6lowpan/iphc.c
View File

@ -366,7 +366,18 @@ lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev,
return err;
}
hdr.payload_len = htons(skb->len);
switch (lowpan_priv(dev)->lltype) {
case LOWPAN_LLTYPE_IEEE802154:
if (lowpan_802154_cb(skb)->d_size)
hdr.payload_len = htons(lowpan_802154_cb(skb)->d_size -
sizeof(struct ipv6hdr));
else
hdr.payload_len = htons(skb->len);
break;
default:
hdr.payload_len = htons(skb->len);
break;
}
pr_debug("skb headroom size = %d, data length = %d\n",
skb_headroom(skb), skb->len);

13
net/6lowpan/nhc_udp.c
View File

@ -71,7 +71,18 @@ static int udp_uncompress(struct sk_buff *skb, size_t needed)
* here, we obtain the hint from the remaining size of the
* frame
*/
uh.len = htons(skb->len + sizeof(struct udphdr));
switch (lowpan_priv(skb->dev)->lltype) {
case LOWPAN_LLTYPE_IEEE802154:
if (lowpan_802154_cb(skb)->d_size)
uh.len = htons(lowpan_802154_cb(skb)->d_size -
sizeof(struct ipv6hdr));
else
uh.len = htons(skb->len + sizeof(struct udphdr));
break;
default:
uh.len = htons(skb->len + sizeof(struct udphdr));
break;
}
pr_debug("uncompressed UDP length: src = %d", ntohs(uh.len));
/* replace the compressed UDP head by the uncompressed UDP

12
net/ieee802154/6lowpan/6lowpan_i.h
View File

@ -7,6 +7,15 @@
#include <net/inet_frag.h>
#include <net/6lowpan.h>
typedef unsigned __bitwise__ lowpan_rx_result;
#define RX_CONTINUE ((__force lowpan_rx_result) 0u)
#define RX_DROP_UNUSABLE ((__force lowpan_rx_result) 1u)
#define RX_DROP ((__force lowpan_rx_result) 2u)
#define RX_QUEUED ((__force lowpan_rx_result) 3u)
#define LOWPAN_DISPATCH_FRAG1 0xc0
#define LOWPAN_DISPATCH_FRAGN 0xe0
struct lowpan_create_arg {
u16 tag;
u16 d_size;
@ -62,4 +71,7 @@ int lowpan_header_create(struct sk_buff *skb, struct net_device *dev,
const void *_saddr, unsigned int len);
netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *dev);
int lowpan_iphc_decompress(struct sk_buff *skb);
lowpan_rx_result lowpan_rx_h_ipv6(struct sk_buff *skb);
#endif /* __IEEE802154_6LOWPAN_I_H__ */

142
net/ieee802154/6lowpan/reassembly.c
View File

@ -32,17 +32,6 @@
static const char lowpan_frags_cache_name[] = "lowpan-frags";
struct lowpan_frag_info {
u16 d_tag;
u16 d_size;
u8 d_offset;
};
static struct lowpan_frag_info *lowpan_cb(struct sk_buff *skb)
{
return (struct lowpan_frag_info *)skb->cb;
}
static struct inet_frags lowpan_frags;
static int lowpan_frag_reasm(struct lowpan_frag_queue *fq,
@ -111,7 +100,7 @@ out:
}
static inline struct lowpan_frag_queue *
fq_find(struct net *net, const struct lowpan_frag_info *frag_info,
fq_find(struct net *net, const struct lowpan_802154_cb *cb,
const struct ieee802154_addr *src,
const struct ieee802154_addr *dst)
{
@ -121,12 +110,12 @@ fq_find(struct net *net, const struct lowpan_frag_info *frag_info,
struct netns_ieee802154_lowpan *ieee802154_lowpan =
net_ieee802154_lowpan(net);
arg.tag = frag_info->d_tag;
arg.d_size = frag_info->d_size;
arg.tag = cb->d_tag;
arg.d_size = cb->d_size;
arg.src = src;
arg.dst = dst;
hash = lowpan_hash_frag(frag_info->d_tag, frag_info->d_size, src, dst);
hash = lowpan_hash_frag(cb->d_tag, cb->d_size, src, dst);
q = inet_frag_find(&ieee802154_lowpan->frags,
&lowpan_frags, &arg, hash);
@ -138,7 +127,7 @@ fq_find(struct net *net, const struct lowpan_frag_info *frag_info,
}
static int lowpan_frag_queue(struct lowpan_frag_queue *fq,
struct sk_buff *skb, const u8 frag_type)
struct sk_buff *skb, u8 frag_type)
{
struct sk_buff *prev, *next;
struct net_device *ldev;
@ -147,8 +136,8 @@ static int lowpan_frag_queue(struct lowpan_frag_queue *fq,
if (fq->q.flags & INET_FRAG_COMPLETE)
goto err;
offset = lowpan_cb(skb)->d_offset << 3;
end = lowpan_cb(skb)->d_size;
offset = lowpan_802154_cb(skb)->d_offset << 3;
end = lowpan_802154_cb(skb)->d_size;
/* Is this the final fragment? */
if (offset + skb->len == end) {
@ -174,13 +163,16 @@ static int lowpan_frag_queue(struct lowpan_frag_queue *fq,
* this fragment, right?
*/
prev = fq->q.fragments_tail;
if (!prev || lowpan_cb(prev)->d_offset < lowpan_cb(skb)->d_offset) {
if (!prev ||
lowpan_802154_cb(prev)->d_offset <
lowpan_802154_cb(skb)->d_offset) {
next = NULL;
goto found;
}
prev = NULL;
for (next = fq->q.fragments; next != NULL; next = next->next) {
if (lowpan_cb(next)->d_offset >= lowpan_cb(skb)->d_offset)
if (lowpan_802154_cb(next)->d_offset >=
lowpan_802154_cb(skb)->d_offset)
break; /* bingo! */
prev = next;
}
@ -200,13 +192,10 @@ found:
skb->dev = NULL;
fq->q.stamp = skb->tstamp;
if (frag_type == LOWPAN_DISPATCH_FRAG1) {
/* Calculate uncomp. 6lowpan header to estimate full size */
fq->q.meat += lowpan_uncompress_size(skb, NULL);
if (frag_type == LOWPAN_DISPATCH_FRAG1)
fq->q.flags |= INET_FRAG_FIRST_IN;
} else {
fq->q.meat += skb->len;
}
fq->q.meat += skb->len;
add_frag_mem_limit(fq->q.net, skb->truesize);
if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
@ -325,24 +314,87 @@ out_oom:
return -1;
}
static int lowpan_get_frag_info(struct sk_buff *skb, const u8 frag_type,
struct lowpan_frag_info *frag_info)
static int lowpan_frag_rx_handlers_result(struct sk_buff *skb,
lowpan_rx_result res)
{
switch (res) {
case RX_QUEUED:
return NET_RX_SUCCESS;
case RX_CONTINUE:
/* nobody cared about this packet */
net_warn_ratelimited("%s: received unknown dispatch\n",
__func__);
/* fall-through */
default:
/* all others failure */
return NET_RX_DROP;
}
}
static lowpan_rx_result lowpan_frag_rx_h_iphc(struct sk_buff *skb)
{
int ret;
if (!lowpan_is_iphc(*skb_network_header(skb)))
return RX_CONTINUE;
ret = lowpan_iphc_decompress(skb);
if (ret < 0)
return RX_DROP;
return RX_QUEUED;
}
static int lowpan_invoke_frag_rx_handlers(struct sk_buff *skb)
{
lowpan_rx_result res;
#define CALL_RXH(rxh) \
do { \
res = rxh(skb); \
if (res != RX_CONTINUE) \
goto rxh_next; \
} while (0)
/* likely at first */
CALL_RXH(lowpan_frag_rx_h_iphc);
CALL_RXH(lowpan_rx_h_ipv6);
rxh_next:
return lowpan_frag_rx_handlers_result(skb, res);
#undef CALL_RXH
}
#define LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK 0x07
#define LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT 8
static int lowpan_get_cb(struct sk_buff *skb, u8 frag_type,
struct lowpan_802154_cb *cb)
{
bool fail;
u8 pattern = 0, low = 0;
u8 high = 0, low = 0;
__be16 d_tag = 0;
fail = lowpan_fetch_skb(skb, &pattern, 1);
fail = lowpan_fetch_skb(skb, &high, 1);
fail |= lowpan_fetch_skb(skb, &low, 1);
frag_info->d_size = (pattern & 7) << 8 | low;
/* remove the dispatch value and use first three bits as high value
* for the datagram size
*/
cb->d_size = (high & LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK) <<
LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT | low;
fail |= lowpan_fetch_skb(skb, &d_tag, 2);
frag_info->d_tag = ntohs(d_tag);
cb->d_tag = ntohs(d_tag);
if (frag_type == LOWPAN_DISPATCH_FRAGN) {
fail |= lowpan_fetch_skb(skb, &frag_info->d_offset, 1);
fail |= lowpan_fetch_skb(skb, &cb->d_offset, 1);
} else {
skb_reset_network_header(skb);
frag_info->d_offset = 0;
cb->d_offset = 0;
/* check if datagram_size has ipv6hdr on FRAG1 */
fail |= cb->d_size < sizeof(struct ipv6hdr);
/* check if we can dereference the dispatch value */
fail |= !skb->len;
}
if (unlikely(fail))
@ -351,27 +403,33 @@ static int lowpan_get_frag_info(struct sk_buff *skb, const u8 frag_type,
return 0;
}
int lowpan_frag_rcv(struct sk_buff *skb, const u8 frag_type)
int lowpan_frag_rcv(struct sk_buff *skb, u8 frag_type)
{
struct lowpan_frag_queue *fq;
struct net *net = dev_net(skb->dev);
struct lowpan_frag_info *frag_info = lowpan_cb(skb);
struct ieee802154_addr source, dest;
struct lowpan_802154_cb *cb = lowpan_802154_cb(skb);
struct ieee802154_hdr hdr;
int err;
source = mac_cb(skb)->source;
dest = mac_cb(skb)->dest;
if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
goto err;
err = lowpan_get_frag_info(skb, frag_type, frag_info);
err = lowpan_get_cb(skb, frag_type, cb);
if (err < 0)
goto err;
if (frag_info->d_size > IPV6_MIN_MTU) {
if (frag_type == LOWPAN_DISPATCH_FRAG1) {
err = lowpan_invoke_frag_rx_handlers(skb);
if (err == NET_RX_DROP)
goto err;
}
if (cb->d_size > IPV6_MIN_MTU) {
net_warn_ratelimited("lowpan_frag_rcv: datagram size exceeds MTU\n");
goto err;
}
fq = fq_find(net, frag_info, &source, &dest);
fq = fq_find(net, cb, &hdr.source, &hdr.dest);
if (fq != NULL) {
int ret;

188
net/ieee802154/6lowpan/rx.c
View File

@ -15,8 +15,9 @@
#include "6lowpan_i.h"
static int lowpan_give_skb_to_device(struct sk_buff *skb,
struct net_device *wdev)
#define LOWPAN_DISPATCH_FRAG_MASK 0xf8
static int lowpan_give_skb_to_device(struct sk_buff *skb)
{
skb->protocol = htons(ETH_P_IPV6);
skb->pkt_type = PACKET_HOST;
@ -24,21 +25,77 @@ static int lowpan_give_skb_to_device(struct sk_buff *skb,
return netif_rx(skb);
}
static int
iphc_decompress(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
static int lowpan_rx_handlers_result(struct sk_buff *skb, lowpan_rx_result res)
{
switch (res) {
case RX_CONTINUE:
/* nobody cared about this packet */
net_warn_ratelimited("%s: received unknown dispatch\n",
__func__);
/* fall-through */
case RX_DROP_UNUSABLE:
kfree_skb(skb);
/* fall-through */
case RX_DROP:
return NET_RX_DROP;
case RX_QUEUED:
return lowpan_give_skb_to_device(skb);
default:
break;
}
return NET_RX_DROP;
}
static inline bool lowpan_is_frag1(u8 dispatch)
{
return (dispatch & LOWPAN_DISPATCH_FRAG_MASK) == LOWPAN_DISPATCH_FRAG1;
}
static inline bool lowpan_is_fragn(u8 dispatch)
{
return (dispatch & LOWPAN_DISPATCH_FRAG_MASK) == LOWPAN_DISPATCH_FRAGN;
}
static lowpan_rx_result lowpan_rx_h_frag(struct sk_buff *skb)
{
int ret;
if (!(lowpan_is_frag1(*skb_network_header(skb)) ||
lowpan_is_fragn(*skb_network_header(skb))))
return RX_CONTINUE;
ret = lowpan_frag_rcv(skb, *skb_network_header(skb) &
LOWPAN_DISPATCH_FRAG_MASK);
if (ret == 1)
return RX_QUEUED;
/* Packet is freed by lowpan_frag_rcv on error or put into the frag
* bucket.
*/
return RX_DROP;
}
int lowpan_iphc_decompress(struct sk_buff *skb)
{
u8 iphc0, iphc1;
struct ieee802154_addr_sa sa, da;
struct ieee802154_hdr hdr;
u8 iphc0, iphc1;
void *sap, *dap;
if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
return -EINVAL;
raw_dump_table(__func__, "raw skb data dump", skb->data, skb->len);
if (lowpan_fetch_skb_u8(skb, &iphc0) ||
lowpan_fetch_skb_u8(skb, &iphc1))
return -EINVAL;
ieee802154_addr_to_sa(&sa, &hdr->source);
ieee802154_addr_to_sa(&da, &hdr->dest);
ieee802154_addr_to_sa(&sa, &hdr.source);
ieee802154_addr_to_sa(&da, &hdr.dest);
if (sa.addr_type == IEEE802154_ADDR_SHORT)
sap = &sa.short_addr;
@ -55,78 +112,87 @@ iphc_decompress(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
IEEE802154_ADDR_LEN, iphc0, iphc1);
}
static lowpan_rx_result lowpan_rx_h_iphc(struct sk_buff *skb)
{
int ret;
if (!lowpan_is_iphc(*skb_network_header(skb)))
return RX_CONTINUE;
/* Setting datagram_offset to zero indicates non frag handling
* while doing lowpan_header_decompress.
*/
lowpan_802154_cb(skb)->d_size = 0;
ret = lowpan_iphc_decompress(skb);
if (ret < 0)
return RX_DROP_UNUSABLE;
return RX_QUEUED;
}
lowpan_rx_result lowpan_rx_h_ipv6(struct sk_buff *skb)
{
if (!lowpan_is_ipv6(*skb_network_header(skb)))
return RX_CONTINUE;
/* Pull off the 1-byte of 6lowpan header. */
skb_pull(skb, 1);
return RX_QUEUED;
}
static int lowpan_invoke_rx_handlers(struct sk_buff *skb)
{
lowpan_rx_result res;
#define CALL_RXH(rxh) \
do { \
res = rxh(skb); \
if (res != RX_CONTINUE) \
goto rxh_next; \
} while (0)
/* likely at first */
CALL_RXH(lowpan_rx_h_iphc);
CALL_RXH(lowpan_rx_h_frag);
CALL_RXH(lowpan_rx_h_ipv6);
rxh_next:
return lowpan_rx_handlers_result(skb, res);
#undef CALL_RXH
}
static int lowpan_rcv(struct sk_buff *skb, struct net_device *wdev,
struct packet_type *pt, struct net_device *orig_wdev)
{
struct ieee802154_hdr hdr;
struct net_device *ldev;
int ret;
if (wdev->type != ARPHRD_IEEE802154 ||
skb->pkt_type == PACKET_OTHERHOST)
goto drop;
return NET_RX_DROP;
ldev = wdev->ieee802154_ptr->lowpan_dev;
if (!ldev || !netif_running(ldev))
goto drop;
return NET_RX_DROP;
/* Replacing skb->dev and followed rx handlers will manipulate skb. */
skb = skb_share_check(skb, GFP_ATOMIC);
if (!skb)
goto drop;
return NET_RX_DROP;
skb->dev = ldev;
if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
goto drop_skb;
/* check that it's our buffer */
if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
/* Pull off the 1-byte of 6lowpan header. */
skb_pull(skb, 1);
return lowpan_give_skb_to_device(skb, wdev);
} else {
switch (skb->data[0] & 0xe0) {
case LOWPAN_DISPATCH_IPHC: /* ipv6 datagram */
ret = iphc_decompress(skb, &hdr);
if (ret < 0)
goto drop_skb;
return lowpan_give_skb_to_device(skb, wdev);
case LOWPAN_DISPATCH_FRAG1: /* first fragment header */
ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAG1);
if (ret == 1) {
ret = iphc_decompress(skb, &hdr);
if (ret < 0)
goto drop_skb;
return lowpan_give_skb_to_device(skb, wdev);
} else if (ret == -1) {
return NET_RX_DROP;
} else {
return NET_RX_SUCCESS;
}
case LOWPAN_DISPATCH_FRAGN: /* next fragments headers */
ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAGN);
if (ret == 1) {
ret = iphc_decompress(skb, &hdr);
if (ret < 0)
goto drop_skb;
return lowpan_give_skb_to_device(skb, wdev);
} else if (ret == -1) {
return NET_RX_DROP;
} else {
return NET_RX_SUCCESS;
}
default:
break;
}
/* When receive frag1 it's likely that we manipulate the buffer.
* When recevie iphc we manipulate the data buffer. So we need
* to unshare the buffer.
*/
if (lowpan_is_frag1(*skb_network_header(skb)) ||
lowpan_is_iphc(*skb_network_header(skb))) {
skb = skb_unshare(skb, GFP_ATOMIC);
if (!skb)
return RX_DROP;
}
drop_skb:
kfree_skb(skb);
drop:
return NET_RX_DROP;
return lowpan_invoke_rx_handlers(skb);
}
static struct packet_type lowpan_packet_type = {