[PATCH net-next v4 3/8] 6lowpan: fix fragmentation on sending side
From: Alexander Aring <alex.aring@gmail.com>
Date: 2014-02-26 16:05:34
Subsystem:
ieee 802.15.4 subsystem, networking [general], the rest · Maintainers:
Alexander Aring, Stefan Schmidt, Miquel Raynal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 size attribute. The main issue is that the datagram size of fragmentation header use the ipv6 payload length, but rfc4944 says it's the ipv6 payload length inclusive network header size (and transport header size if compressed). Signed-off-by: Alexander Aring <alex.aring@gmail.com> --- net/ieee802154/6lowpan.c | 37 +++++++++++++++++++++++++++---------- 1 file changed, 27 insertions(+), 10 deletions(-)
diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index 8edfea5..872c8f9 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c@@ -422,44 +422,60 @@ 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; + u16 dgram_offset, dgram_size, payload_length, header_length, + lowpan_size, frag_plen, offset, tag; u8 head[5]; header_length = skb->mac_len; payload_length = skb->len - header_length; tag = lowpan_dev_info(dev)->fragment_tag++; + lowpan_size = skb_network_header_len(skb); + dgram_size = lowpan_uncompress_size(skb, &dgram_offset) - + header_length; /* 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 += 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 >> 3; 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);
@@ -467,6 +483,7 @@ lowpan_skb_fragmentation(struct sk_buff *skb, struct net_device *dev) } offset += len; + dgram_offset += len; } exit:
--
1.9.0