This patch fix the fragmentation on sending side according to rfc4944.
Also add improvement to use the full payload of a PDU which calculate the
nearest divided to 8 payload length for the fragmentation datagram
offset attribute.
Signed-off-by: Alexander Aring <alex.ar...@gmail.com>
---
net/ieee802154/6lowpan.c | 41 +++++++++++++++++++++++++++++++----------
1 file changed, 31 insertions(+), 10 deletions(-)
diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index 9497c6f..dd7864f 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -374,6 +374,7 @@ lowpan_compress_udp_header(u8 **hc06_ptr, struct sk_buff
*skb)
memcpy(*hc06_ptr, &uh->check, 2);
*hc06_ptr += 2;
+ mac_cb(skb)->frag_info.d_offset += sizeof(struct udphdr);
/* skip the UDP header */
skb_pull(skb, sizeof(struct udphdr));
}
@@ -484,6 +485,7 @@ static int lowpan_header_create(struct sk_buff *skb,
if (type != ETH_P_IPV6)
return 0;
+ mac_cb(skb)->frag_info.d_offset = 0;
hdr = ipv6_hdr(skb);
hc06_ptr = head + 2;
@@ -653,6 +655,11 @@ static int lowpan_header_create(struct sk_buff *skb,
head[0] = iphc0;
head[1] = iphc1;
+ /* Before replace ipv6hdr to 6lowpan header we save the dgram_size */
+ mac_cb(skb)->frag_info.d_size = ntohs(hdr->payload_len) +
+ sizeof(struct ipv6hdr);
+ mac_cb(skb)->frag_info.d_offset += sizeof(struct ipv6hdr);
+
skb_pull(skb, sizeof(struct ipv6hdr));
skb_reset_transport_header(skb);
memcpy(skb_push(skb, hc06_ptr - head), head, hc06_ptr - head);
@@ -1141,44 +1148,57 @@ lowpan_fragment_xmit(struct sk_buff *skb, u8 *head,
static int
lowpan_skb_fragmentation(struct sk_buff *skb, struct net_device *dev)
{
- int err, header_length, payload_length, tag, offset = 0;
+ int err, header_length, payload_length, tag, dgram_size,
+ dgram_offset, lowpan_size, frag_plen, offset = 0;
u8 head[5];
header_length = skb->mac_len;
payload_length = skb->len - header_length;
tag = lowpan_dev_info(dev)->fragment_tag++;
+ lowpan_size = skb->transport_header - skb->network_header;
+ dgram_size = mac_cb(skb)->frag_info.d_size;
/* first fragment header */
- head[0] = LOWPAN_DISPATCH_FRAG1 | ((payload_length >> 8) & 0x7);
- head[1] = payload_length & 0xff;
+ head[0] = LOWPAN_DISPATCH_FRAG1 | ((dgram_size >> 8) & 0x7);
+ head[1] = dgram_size & 0xff;
head[2] = tag >> 8;
head[3] = tag & 0xff;
- err = lowpan_fragment_xmit(skb, head, header_length, LOWPAN_FRAG_SIZE,
- 0, LOWPAN_DISPATCH_FRAG1);
+ /* calc the nearest payload length(divided to 8) for first fragment
+ * which fits into a IEEE802154_MTU
+ */
+ frag_plen = round_down(IEEE802154_MTU - header_length -
+ LOWPAN_FRAG1_HEAD_SIZE - lowpan_size -
+ IEEE802154_MFR_SIZE, 8);
+ err = lowpan_fragment_xmit(skb, head, header_length,
+ frag_plen + lowpan_size, 0, LOWPAN_DISPATCH_FRAG1);
if (err) {
pr_debug("%s unable to send FRAG1 packet (tag: %d)",
__func__, tag);
goto exit;
}
- offset = LOWPAN_FRAG_SIZE;
+ offset = lowpan_size + frag_plen;
+ dgram_offset = mac_cb(skb)->frag_info.d_offset + frag_plen;
/* next fragment header */
head[0] &= ~LOWPAN_DISPATCH_FRAG1;
head[0] |= LOWPAN_DISPATCH_FRAGN;
+ frag_plen = round_down(IEEE802154_MTU - header_length -
+ LOWPAN_FRAGN_HEAD_SIZE - IEEE802154_MFR_SIZE, 8);
+
while (payload_length - offset > 0) {
- int len = LOWPAN_FRAG_SIZE;
+ int len = frag_plen;
- head[4] = offset / 8;
+ head[4] = dgram_offset / 8;
if (payload_length - offset < len)
len = payload_length - offset;
- err = lowpan_fragment_xmit(skb, head, header_length,
- len, offset, LOWPAN_DISPATCH_FRAGN);
+ err = lowpan_fragment_xmit(skb, head, header_length, len,
+ offset, LOWPAN_DISPATCH_FRAGN);
if (err) {
pr_debug("%s unable to send a subsequent FRAGN packet "
"(tag: %d, offset: %d", __func__, tag, offset);
@@ -1186,6 +1206,7 @@ lowpan_skb_fragmentation(struct sk_buff *skb, struct
net_device *dev)
}
offset += len;
+ dgram_offset += len;
}
exit:
--
1.8.4.2
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