mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-26 05:34:13 +08:00
6LoWPAN: add fragmentation support
This patch adds support for frame fragmentation. Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
alex.bluesman.smirnov@gmail.com
David S. Miller
parent
2a24444f8f
commit
719269afbc
@ -21,11 +21,14 @@
|
||||
* Maxim Gorbachyov <maxim.gorbachev@siemens.com>
|
||||
* Maxim Osipov <maxim.osipov@siemens.com>
|
||||
* Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
|
||||
* Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
|
||||
*/
|
||||
|
||||
#ifndef NET_IEEE802154_H
|
||||
#define NET_IEEE802154_H
|
||||
|
||||
#define IEEE802154_MTU 127
|
||||
|
||||
#define IEEE802154_FC_TYPE_BEACON 0x0 /* Frame is beacon */
|
||||
#define IEEE802154_FC_TYPE_DATA 0x1 /* Frame is data */
|
||||
#define IEEE802154_FC_TYPE_ACK 0x2 /* Frame is acknowledgment */
|
||||
@ -56,6 +59,9 @@
|
||||
(((x) & IEEE802154_FC_DAMODE_MASK) >> IEEE802154_FC_DAMODE_SHIFT)
|
||||
|
||||
|
||||
/* MAC footer size */
|
||||
#define IEEE802154_MFR_SIZE 2 /* 2 octets */
|
||||
|
||||
/* MAC's Command Frames Identifiers */
|
||||
#define IEEE802154_CMD_ASSOCIATION_REQ 0x01
|
||||
#define IEEE802154_CMD_ASSOCIATION_RESP 0x02
|
||||
|
||||
@ -113,6 +113,20 @@ struct lowpan_dev_record {
|
||||
struct list_head list;
|
||||
};
|
||||
|
||||
struct lowpan_fragment {
|
||||
struct sk_buff *skb; /* skb to be assembled */
|
||||
spinlock_t lock; /* concurency lock */
|
||||
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);
|
||||
spinlock_t flist_lock;
|
||||
|
||||
static inline struct
|
||||
lowpan_dev_info *lowpan_dev_info(const struct net_device *dev)
|
||||
{
|
||||
@ -244,6 +258,17 @@ static u8 lowpan_fetch_skb_u8(struct sk_buff *skb)
|
||||
return ret;
|
||||
}
|
||||
|
||||
static u16 lowpan_fetch_skb_u16(struct sk_buff *skb)
|
||||
{
|
||||
u16 ret;
|
||||
|
||||
BUG_ON(!pskb_may_pull(skb, 2));
|
||||
|
||||
ret = skb->data[0] | (skb->data[1] << 8);
|
||||
skb_pull(skb, 2);
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int lowpan_header_create(struct sk_buff *skb,
|
||||
struct net_device *dev,
|
||||
unsigned short type, const void *_daddr,
|
||||
@ -467,6 +492,7 @@ static int lowpan_header_create(struct sk_buff *skb,
|
||||
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);
|
||||
}
|
||||
@ -511,6 +537,21 @@ static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
|
||||
return stat;
|
||||
}
|
||||
|
||||
static void lowpan_fragment_timer_expired(unsigned long entry_addr)
|
||||
{
|
||||
struct lowpan_fragment *entry = (struct lowpan_fragment *)entry_addr;
|
||||
|
||||
pr_debug("%s: timer expired for frame with tag %d\n", __func__,
|
||||
entry->tag);
|
||||
|
||||
spin_lock(&flist_lock);
|
||||
list_del(&entry->list);
|
||||
spin_unlock(&flist_lock);
|
||||
|
||||
dev_kfree_skb(entry->skb);
|
||||
kfree(entry);
|
||||
}
|
||||
|
||||
static int
|
||||
lowpan_process_data(struct sk_buff *skb)
|
||||
{
|
||||
@ -525,6 +566,107 @@ lowpan_process_data(struct sk_buff *skb)
|
||||
if (skb->len < 2)
|
||||
goto drop;
|
||||
iphc0 = lowpan_fetch_skb_u8(skb);
|
||||
|
||||
/* fragments assembling */
|
||||
switch (iphc0 & LOWPAN_DISPATCH_MASK) {
|
||||
case LOWPAN_DISPATCH_FRAG1:
|
||||
case LOWPAN_DISPATCH_FRAGN:
|
||||
{
|
||||
struct lowpan_fragment *frame;
|
||||
u8 len, offset;
|
||||
u16 tag;
|
||||
bool found = false;
|
||||
|
||||
len = lowpan_fetch_skb_u8(skb); /* frame length */
|
||||
tag = lowpan_fetch_skb_u16(skb);
|
||||
|
||||
/*
|
||||
* check if frame assembling with the same tag is
|
||||
* already in progress
|
||||
*/
|
||||
spin_lock(&flist_lock);
|
||||
|
||||
list_for_each_entry(frame, &lowpan_fragments, list)
|
||||
if (frame->tag == tag) {
|
||||
found = true;
|
||||
break;
|
||||
}
|
||||
|
||||
/* alloc new frame structure */
|
||||
if (!found) {
|
||||
frame = kzalloc(sizeof(struct lowpan_fragment),
|
||||
GFP_ATOMIC);
|
||||
if (!frame)
|
||||
goto unlock_and_drop;
|
||||
|
||||
INIT_LIST_HEAD(&frame->list);
|
||||
|
||||
frame->length = (iphc0 & 7) | (len << 3);
|
||||
frame->tag = tag;
|
||||
|
||||
/* allocate buffer for frame assembling */
|
||||
frame->skb = alloc_skb(frame->length +
|
||||
sizeof(struct ipv6hdr), GFP_ATOMIC);
|
||||
|
||||
if (!frame->skb) {
|
||||
kfree(frame);
|
||||
goto unlock_and_drop;
|
||||
}
|
||||
|
||||
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);
|
||||
}
|
||||
|
||||
if ((iphc0 & LOWPAN_DISPATCH_MASK) == LOWPAN_DISPATCH_FRAG1)
|
||||
goto unlock_and_drop;
|
||||
|
||||
offset = lowpan_fetch_skb_u8(skb); /* fetch offset */
|
||||
|
||||
/* 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(&frame->timer);
|
||||
list_del(&frame->list);
|
||||
spin_unlock(&flist_lock);
|
||||
|
||||
dev_kfree_skb(skb);
|
||||
skb = frame->skb;
|
||||
kfree(frame);
|
||||
iphc0 = lowpan_fetch_skb_u8(skb);
|
||||
break;
|
||||
}
|
||||
spin_unlock(&flist_lock);
|
||||
|
||||
return kfree_skb(skb), 0;
|
||||
}
|
||||
default:
|
||||
break;
|
||||
}
|
||||
|
||||
iphc1 = lowpan_fetch_skb_u8(skb);
|
||||
|
||||
_saddr = mac_cb(skb)->sa.hwaddr;
|
||||
@ -674,6 +816,9 @@ lowpan_process_data(struct sk_buff *skb)
|
||||
lowpan_raw_dump_table(__func__, "raw header dump", (u8 *)&hdr,
|
||||
sizeof(hdr));
|
||||
return lowpan_skb_deliver(skb, &hdr);
|
||||
|
||||
unlock_and_drop:
|
||||
spin_unlock(&flist_lock);
|
||||
drop:
|
||||
kfree_skb(skb);
|
||||
return -EINVAL;
|
||||
@ -692,18 +837,118 @@ static int lowpan_set_address(struct net_device *dev, void *p)
|
||||
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);
|
||||
|
||||
if (ret < 0)
|
||||
dev_kfree_skb(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 & 0x7);
|
||||
head[1] = (payload_length >> 3) & 0xff;
|
||||
head[2] = tag & 0xff;
|
||||
head[3] = tag >> 8;
|
||||
|
||||
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 = 0;
|
||||
int err = -1;
|
||||
|
||||
pr_debug("(%s): package xmit\n", __func__);
|
||||
|
||||
skb->dev = lowpan_dev_info(dev)->real_dev;
|
||||
if (skb->dev == NULL) {
|
||||
pr_debug("(%s) ERROR: no real wpan device found\n", __func__);
|
||||
dev_kfree_skb(skb);
|
||||
} else
|
||||
goto error;
|
||||
}
|
||||
|
||||
if (skb->len <= IEEE802154_MTU) {
|
||||
err = dev_queue_xmit(skb);
|
||||
goto out;
|
||||
}
|
||||
|
||||
pr_debug("(%s): frame is too big, fragmentation is needed\n",
|
||||
__func__);
|
||||
err = lowpan_skb_fragmentation(skb);
|
||||
error:
|
||||
dev_kfree_skb(skb);
|
||||
out:
|
||||
if (err < 0)
|
||||
pr_debug("(%s): ERROR: xmit failed\n", __func__);
|
||||
|
||||
return (err < 0 ? NETDEV_TX_BUSY : NETDEV_TX_OK);
|
||||
}
|
||||
@ -765,8 +1010,15 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
|
||||
goto drop;
|
||||
|
||||
/* check that it's our buffer */
|
||||
if ((skb->data[0] & 0xe0) == 0x60)
|
||||
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 */
|
||||
lowpan_process_data(skb);
|
||||
break;
|
||||
default:
|
||||
break;
|
||||
}
|
||||
|
||||
return NET_RX_SUCCESS;
|
||||
|
||||
|
||||
@ -159,6 +159,24 @@
|
||||
#define LOWPAN_DISPATCH_FRAG1 0xc0 /* 11000xxx */
|
||||
#define LOWPAN_DISPATCH_FRAGN 0xe0 /* 11100xxx */
|
||||
|
||||
#define LOWPAN_DISPATCH_MASK 0xf8 /* 11111000 */
|
||||
|
||||
#define LOWPAN_FRAG_TIMEOUT (HZ * 60) /* time-out 60 sec */
|
||||
|
||||
#define LOWPAN_FRAG1_HEAD_SIZE 0x4
|
||||
#define LOWPAN_FRAGN_HEAD_SIZE 0x5
|
||||
|
||||
/*
|
||||
* According IEEE802.15.4 standard:
|
||||
* - MTU is 127 octets
|
||||
* - maximum MHR size is 37 octets
|
||||
* - MFR size is 2 octets
|
||||
*
|
||||
* so minimal payload size that we may guarantee is:
|
||||
* MTU - MHR - MFR = 88 octets
|
||||
*/
|
||||
#define LOWPAN_FRAG_SIZE 88
|
||||
|
||||
/*
|
||||
* Values of fields within the IPHC encoding first byte
|
||||
* (C stands for compressed and I for inline)
|
||||
|
||||
Loading…
Reference in New Issue
Block a user