On 10/27/2011 07:42 PM, Alexander Smirnov wrote:
> This patch adds support for compression/decompression of UDP header
> of ipv6 datagram.
Could you please try to prepare a separate patch, containing a split of
lowpan_header_create and lowpan_process_data functions into pieces,
where each part will consume exactly one header. Then resubmit this one
as based on the split up patch.
>
> Derived from Contiki OS
>
> Signed-off-by: Alexander Smirnov<alex.bluesman.smir...@gmail.com>
> ---
> net/ieee802154/6lowpan.c | 101
> +++++++++++++++++++++++++++++++++++++++++++--
> net/ieee802154/6lowpan.h | 5 ++
> 2 files changed, 101 insertions(+), 5 deletions(-)
>
> diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
> index 1ee6d1c..9f3e270 100644
> --- a/net/ieee802154/6lowpan.c
> +++ b/net/ieee802154/6lowpan.c
> @@ -367,8 +367,6 @@ static int lowpan_header_create(struct sk_buff *skb,
> if (hdr->nexthdr == UIP_PROTO_UDP)
> iphc0 |= LOWPAN_IPHC_NH_C;
>
> -/* TODO: next header compression */
> -
> if ((iphc0& LOWPAN_IPHC_NH_C) == 0) {
> *hc06_ptr = hdr->nexthdr;
> hc06_ptr += 1;
> @@ -456,8 +454,53 @@ static int lowpan_header_create(struct sk_buff *skb,
> }
> }
>
> - /* TODO: UDP header compression */
> - /* TODO: Next Header compression */
> + /* UDP header compression */
> + if (hdr->nexthdr == UIP_PROTO_UDP) {
> + struct udphdr *uh = udp_hdr(skb);
> +
> + pr_debug("(%s): UDP header compression\n", __func__);
> +
> + if (((uh->source& LOWPAN_NHC_UDP_4BIT_MASK) ==
> + LOWPAN_NHC_UDP_4BIT_PORT)&&
> + ((uh->dest& LOWPAN_NHC_UDP_4BIT_MASK) ==
> + LOWPAN_NHC_UDP_4BIT_PORT)) {
> + pr_debug("(%s): both ports compression to 4 bits\n",
> + __func__);
> + *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 += 2;
> + } else if ((uh->dest& LOWPAN_NHC_UDP_8BIT_MASK) ==
> + LOWPAN_NHC_UDP_8BIT_PORT) {
> + pr_debug("(%s): remove 8 bits of dest\n", __func__);
> + *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 += 4;
> + } else if ((uh->source& LOWPAN_NHC_UDP_8BIT_MASK) ==
> + LOWPAN_NHC_UDP_8BIT_PORT) {
> + pr_debug("(%s): remove 8 bits of source\n", __func__);
> + *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 += 4;
> + } else {
> + pr_debug("(%s): can't compress header\n", __func__);
> + *hc06_ptr = LOWPAN_NHC_UDP_CS_P_00;
> + memcpy(hc06_ptr + 1,&uh->source, 2);
> + memcpy(hc06_ptr + 3,&uh->dest, 2);
> + hc06_ptr += 5;
> + }
> +
> + /* checksum is always inline */
> + memcpy(hc06_ptr,&uh->check, 2);
> + hc06_ptr += 2;
> + }
> +
> + /* TODO: other NH types support? */
>
> head[0] = iphc0;
> head[1] = iphc1;
> @@ -799,7 +842,55 @@ lowpan_process_data(struct sk_buff *skb)
> goto drop;
> }
>
> - /* TODO: UDP header parse */
> + /* UDP data uncompression */
> + if (iphc0& LOWPAN_IPHC_NH_C) {
> + tmp = lowpan_fetch_skb_u8(skb);
> +
> + if ((tmp& LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) {
> + struct udphdr *uh = udp_hdr(skb);
> +
> + pr_debug("(%s): UDP header uncompression\n", __func__);
> + 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);
> + 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);
> + 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);
> + 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);
> + break;
> + default:
> + pr_debug("(%s) ERROR: unknown UDP format\n",
> __func__);
> + goto drop;
> + }
> +
> + pr_debug("(%s): uncompressed UDP ports: src = %d, dst =
> %d\n",
> + __func__, uh->source, uh->dest);
> +
> + /* copy checksum */
> + memcpy(&uh->check,&skb->data[0], 2);
> + skb_pull(skb, 2);
> + } else {
> + pr_debug("(%s): ERROR: unsupported NH format\n",
> + __func__);
> + goto drop;
> + }
> + }
>
> /* Not fragmented package */
> hdr.payload_len = htons(skb->len);
> diff --git a/net/ieee802154/6lowpan.h b/net/ieee802154/6lowpan.h
> index eeb5446..31e0d5e 100644
> --- a/net/ieee802154/6lowpan.h
> +++ b/net/ieee802154/6lowpan.h
> @@ -219,6 +219,11 @@
> #define LOWPAN_NHC_UDP_CHECKSUMC 0x04
> #define LOWPAN_NHC_UDP_CHECKSUMI 0x00
>
> +#define LOWPAN_NHC_UDP_4BIT_PORT 0xF0B0
> +#define LOWPAN_NHC_UDP_4BIT_MASK 0xFFF0
> +#define LOWPAN_NHC_UDP_8BIT_PORT 0xF000
> +#define LOWPAN_NHC_UDP_8BIT_MASK 0xFF00
> +
> /* values for port compression, _with checksum_ ie bit 5 set to 0 */
> #define LOWPAN_NHC_UDP_CS_P_00 0xF0 /* all inline */
> #define LOWPAN_NHC_UDP_CS_P_01 0xF1 /* source 16bit inline,
--
With best wishes
Dmitry
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