From 96cb3eb7a1a5f0c3598500a2348f7d2cc76afbd2 Mon Sep 17 00:00:00 2001 From: Alexander Aring Date: Fri, 28 Feb 2014 07:32:45 +0100 Subject: [PATCH] 6lowpan: fix fragmentation on sending side 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 Signed-off-by: David S. Miller --- net/ieee802154/6lowpan.c | 39 ++++++++++++++++++++++++++++----------- 1 file changed, 28 insertions(+), 11 deletions(-) diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c index 8edfea5da572..872c8f97a30c 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; - while (payload_length - offset > 0) { - int len = LOWPAN_FRAG_SIZE; + frag_plen = round_down(IEEE802154_MTU - header_length - + LOWPAN_FRAGN_HEAD_SIZE - IEEE802154_MFR_SIZE, 8); - head[4] = offset / 8; + while (payload_length - offset > 0) { + int len = frag_plen; + + 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: