6lowpan: fix first fragment (FRAG1) handling
The first fragment, FRAG1, must contain some payload according to the
specs. However, as it is currently written, the first fragment will
remain empty and only contain the 6lowpan headers.
This patch also extracts the transport layer information from the first
fragment. This information is used later on when uncompressing UDP
header.
Thanks to Wolf-Bastian Pöttner for noticing that the offset value was
not properly initialized.
Signed-off-by: Tony Cheneau <tony.cheneau@amnesiak.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index 0eebb96..4a62289 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -661,7 +661,7 @@
}
static struct lowpan_fragment *
-lowpan_alloc_new_frame(struct sk_buff *skb, u8 len, u16 tag)
+lowpan_alloc_new_frame(struct sk_buff *skb, u16 len, u16 tag)
{
struct lowpan_fragment *frame;
@@ -731,7 +731,7 @@
{
struct lowpan_fragment *frame;
/* slen stores the rightmost 8 bits of the 11 bits length */
- u8 slen, offset;
+ u8 slen, offset = 0;
u16 len, tag;
bool found = false;
@@ -742,6 +742,12 @@
/* adds the 3 MSB to the 8 LSB to retrieve the 11 bits length */
len = ((iphc0 & 7) << 8) | slen;
+ /* FRAGN */
+ if ((iphc0 & LOWPAN_DISPATCH_MASK) != LOWPAN_DISPATCH_FRAG1) {
+ if (lowpan_fetch_skb_u8(skb, &offset))
+ goto unlock_and_drop;
+ }
+
/*
* check if frame assembling with the same tag is
* already in progress
@@ -761,12 +767,6 @@
goto unlock_and_drop;
}
- if ((iphc0 & LOWPAN_DISPATCH_MASK) == LOWPAN_DISPATCH_FRAG1)
- goto unlock_and_drop;
-
- if (lowpan_fetch_skb_u8(skb, &offset)) /* fetch offset */
- goto unlock_and_drop;
-
/* if payload fits buffer, copy it */
if (likely((offset * 8 + skb->len) <= frame->length))
skb_copy_to_linear_data_offset(frame->skb, offset * 8,
@@ -982,13 +982,13 @@
static int
lowpan_fragment_xmit(struct sk_buff *skb, u8 *head,
- int mlen, int plen, int offset)
+ int mlen, int plen, int offset, int type)
{
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);
+ hlen = (type == LOWPAN_DISPATCH_FRAG1) ?
+ LOWPAN_FRAG1_HEAD_SIZE : LOWPAN_FRAGN_HEAD_SIZE;
lowpan_raw_dump_inline(__func__, "6lowpan fragment header", head, hlen);
@@ -1031,7 +1031,13 @@
head[2] = tag >> 8;
head[3] = tag & 0xff;
- err = lowpan_fragment_xmit(skb, head, header_length, 0, 0);
+ err = lowpan_fragment_xmit(skb, head, header_length, LOWPAN_FRAG_SIZE,
+ 0, LOWPAN_DISPATCH_FRAG1);
+
+ if (err)
+ goto exit;
+
+ offset = LOWPAN_FRAG_SIZE;
/* next fragment header */
head[0] &= ~LOWPAN_DISPATCH_FRAG1;
@@ -1046,10 +1052,14 @@
len = payload_length - offset;
err = lowpan_fragment_xmit(skb, head, header_length,
- len, offset);
+ len, offset, LOWPAN_DISPATCH_FRAGN);
+ if (err)
+ goto exit;
+
offset += len;
}
+exit:
return err;
}