The current udp compression/uncompression have several issues.
A list of founded issues:
1. Byteordering issues in both functions which indicate that these functions
never worked correctly.
2. Fixing derefecening issue which occurs a deferencing nullpointer
sometimes.
3. Compress source port at first then destination port. This is switched
in case ((ntohs(uh->source) & LOWPAN_NHC_UDP_8BIT_MASK) of udp header
compress function.
4. Add failure case if we get a elided checksum while uncompress udp header.
This is currently not supported.
Other fixes/improvements are that this patch get udp compression working with
the new fragmentation implementation and uses the lowpan_fetch_skb function.
Signed-off-by: Alexander Aring <alex.ar...@gmail.com>
Acked-by: Werner Almesberger <wer...@almesberger.net>
---
net/ieee802154/6lowpan.c | 96 +++++++++++++++++++++++++++---------------------
net/ieee802154/6lowpan.h | 1 +
2 files changed, 56 insertions(+), 41 deletions(-)
diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index a819b28..2dbd675 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -341,29 +341,31 @@ lowpan_compress_udp_header(u8 **hc06_ptr, struct sk_buff
*skb)
{
struct udphdr *uh = udp_hdr(skb);
- if (((uh->source & LOWPAN_NHC_UDP_4BIT_MASK) ==
+ if (((ntohs(uh->source) & LOWPAN_NHC_UDP_4BIT_MASK) ==
LOWPAN_NHC_UDP_4BIT_PORT) &&
- ((uh->dest & LOWPAN_NHC_UDP_4BIT_MASK) ==
+ ((ntohs(uh->dest) & LOWPAN_NHC_UDP_4BIT_MASK) ==
LOWPAN_NHC_UDP_4BIT_PORT)) {
pr_debug("UDP header: both ports compression to 4 bits\n");
**hc06_ptr = LOWPAN_NHC_UDP_CS_P_11;
- **(hc06_ptr + 1) = /* subtraction is faster */
- (u8)((uh->dest - LOWPAN_NHC_UDP_4BIT_PORT) +
- ((uh->source & LOWPAN_NHC_UDP_4BIT_PORT) << 4));
+ *(*hc06_ptr + 1) = /* subtraction is faster */
+ (u8)((ntohs(uh->dest) - LOWPAN_NHC_UDP_4BIT_PORT) +
+ ((ntohs(uh->source) - LOWPAN_NHC_UDP_4BIT_PORT) << 4));
*hc06_ptr += 2;
- } else if ((uh->dest & LOWPAN_NHC_UDP_8BIT_MASK) ==
+ } else if ((ntohs(uh->dest) & LOWPAN_NHC_UDP_8BIT_MASK) ==
LOWPAN_NHC_UDP_8BIT_PORT) {
pr_debug("UDP header: remove 8 bits of dest\n");
**hc06_ptr = LOWPAN_NHC_UDP_CS_P_01;
memcpy(*hc06_ptr + 1, &uh->source, 2);
- **(hc06_ptr + 3) = (u8)(uh->dest - LOWPAN_NHC_UDP_8BIT_PORT);
+ *(*hc06_ptr + 3) = (u8)(ntohs(uh->dest) -
+ LOWPAN_NHC_UDP_8BIT_PORT);
*hc06_ptr += 4;
- } else if ((uh->source & LOWPAN_NHC_UDP_8BIT_MASK) ==
+ } else if ((ntohs(uh->source) & LOWPAN_NHC_UDP_8BIT_MASK) ==
LOWPAN_NHC_UDP_8BIT_PORT) {
pr_debug("UDP header: remove 8 bits of source\n");
**hc06_ptr = LOWPAN_NHC_UDP_CS_P_10;
- memcpy(*hc06_ptr + 1, &uh->dest, 2);
- **(hc06_ptr + 3) = (u8)(uh->source - LOWPAN_NHC_UDP_8BIT_PORT);
+ *(*hc06_ptr + 1) = (u8)(ntohs(uh->source) -
+ LOWPAN_NHC_UDP_8BIT_PORT);
+ memcpy(*hc06_ptr + 2, &uh->dest, 2);
*hc06_ptr += 4;
} else {
pr_debug("UDP header: can't compress\n");
@@ -405,67 +407,73 @@ static inline int lowpan_fetch_skb_u16(struct sk_buff
*skb, u16 *val)
}
static int
-lowpan_uncompress_udp_header(struct sk_buff *skb, struct udphdr *uh)
+lowpan_uncompress_udp_header(struct sk_buff *skb,
+ struct udphdr *uh, size_t udplen)
{
- u8 tmp;
+ bool fail;
+ u8 tmp = 0, val = 0;
- if (!uh)
- goto err;
-
- if (lowpan_fetch_skb_u8(skb, &tmp))
- goto err;
+ fail = lowpan_fetch_skb(skb, &tmp, 1);
if ((tmp & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) {
pr_debug("UDP header uncompression\n");
switch (tmp & LOWPAN_NHC_UDP_CS_P_11) {
case LOWPAN_NHC_UDP_CS_P_00:
- memcpy(&uh->source, &skb->data[0], 2);
- memcpy(&uh->dest, &skb->data[2], 2);
- skb_pull(skb, 4);
+ fail |= lowpan_fetch_skb(skb, &uh->source, 2);
+ fail |= lowpan_fetch_skb(skb, &uh->dest, 2);
break;
case LOWPAN_NHC_UDP_CS_P_01:
- memcpy(&uh->source, &skb->data[0], 2);
- uh->dest =
- skb->data[2] + LOWPAN_NHC_UDP_8BIT_PORT;
- skb_pull(skb, 3);
+ fail |= lowpan_fetch_skb(skb, &uh->source, 2);
+ fail |= lowpan_fetch_skb(skb, &val, 1);
+ uh->dest = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
break;
case LOWPAN_NHC_UDP_CS_P_10:
- uh->source = skb->data[0] + LOWPAN_NHC_UDP_8BIT_PORT;
- memcpy(&uh->dest, &skb->data[1], 2);
- skb_pull(skb, 3);
+ fail |= lowpan_fetch_skb(skb, &val, 1);
+ uh->source = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
+ fail |= lowpan_fetch_skb(skb, &uh->dest, 2);
break;
case LOWPAN_NHC_UDP_CS_P_11:
- uh->source =
- LOWPAN_NHC_UDP_4BIT_PORT + (skb->data[0] >> 4);
- uh->dest =
- LOWPAN_NHC_UDP_4BIT_PORT + (skb->data[0] & 0x0f);
- skb_pull(skb, 1);
+ fail |= lowpan_fetch_skb(skb, &val, 1);
+ uh->source = htons(LOWPAN_NHC_UDP_4BIT_PORT +
+ (val >> 4));
+ uh->dest = htons(LOWPAN_NHC_UDP_4BIT_PORT +
+ (val & 0x0f));
break;
default:
pr_debug("ERROR: unknown UDP format\n");
goto err;
- break;
}
pr_debug("uncompressed UDP ports: src = %d, dst = %d\n",
- uh->source, uh->dest);
+ ntohs(uh->source), ntohs(uh->dest));
- /* copy checksum */
- memcpy(&uh->check, &skb->data[0], 2);
- skb_pull(skb, 2);
+ /* checksum */
+ if (tmp & LOWPAN_NHC_UDP_CS_C) {
+ pr_debug("checksum elided currently not supported");
+ goto err;
+ } else {
+ fail |= lowpan_fetch_skb(skb, &uh->check, 2);
+ }
/*
* UDP lenght needs to be infered from the lower layers
* here, we obtain the hint from the remaining size of the
* frame
*/
- uh->len = htons(skb->len + sizeof(struct udphdr));
- pr_debug("uncompressed UDP length: src = %d", uh->len);
+ if (udplen)
+ uh->len = htons(udplen);
+ else
+ uh->len = htons(skb->len + sizeof(struct udphdr));
+
+ pr_debug("uncompressed UDP length: src = %d", ntohs(uh->len));
} else {
pr_debug("ERROR: unsupported NH format\n");
goto err;
}
+ if (fail)
+ goto err;
+
return 0;
err:
return -EINVAL;
@@ -936,8 +944,14 @@ lowpan_process_data(struct sk_buff *skb, size_t d_size)
if (iphc0 & LOWPAN_IPHC_NH_C) {
struct udphdr uh;
- if (lowpan_uncompress_udp_header(skb, &uh))
- goto drop;
+ if (d_size) {
+ if (lowpan_uncompress_udp_header(skb, &uh, d_size -
+ sizeof(struct ipv6hdr)))
+ goto drop;
+ } else {
+ if (lowpan_uncompress_udp_header(skb, &uh, 0))
+ goto drop;
+ }
skb_push(skb, sizeof(struct udphdr));
skb_copy_to_linear_data(skb, &uh, sizeof(struct udphdr));
diff --git a/net/ieee802154/6lowpan.h b/net/ieee802154/6lowpan.h
index 05a2a37..0109b5d 100644
--- a/net/ieee802154/6lowpan.h
+++ b/net/ieee802154/6lowpan.h
@@ -231,6 +231,7 @@
#define LOWPAN_NHC_UDP_CS_P_10 0xF2 /* source = 0xF0 + 8bit inline,
dest = 16 bit inline */
#define LOWPAN_NHC_UDP_CS_P_11 0xF3 /* source & dest = 0xF0B + 4bit inline */
+#define LOWPAN_NHC_UDP_CS_C 0x04 /* checksum elided */
static inline bool lowpan_fetch_skb(struct sk_buff *skb,
void *data, const unsigned int len)
--
1.8.4
------------------------------------------------------------------------------
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