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Date: Fri, 28 Feb 2014 07:32:44 +0100
From: Alexander Aring <alex.aring@...il.com>
To: alex.bluesman.smirnov@...il.com
Cc: dbaryshkov@...il.com, davem@...emloft.net,
linux-zigbee-devel@...ts.sourceforge.net, netdev@...r.kernel.org,
martin.townsend@...lon.com, Alexander Aring <alex.aring@...il.com>
Subject: [PATCH net-next v6 2/8] 6lowpan: add uncompress header size function
This patch add a lookup function for uncompressed 6LoWPAN header
size. This is needed to estimate the real size after uncompress the
6LoWPAN header.
Signed-off-by: Alexander Aring <alex.aring@...il.com>
---
net/ieee802154/6lowpan.h | 113 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 113 insertions(+)
diff --git a/net/ieee802154/6lowpan.h b/net/ieee802154/6lowpan.h
index 2b835db..0dccf62 100644
--- a/net/ieee802154/6lowpan.h
+++ b/net/ieee802154/6lowpan.h
@@ -306,6 +306,119 @@ static inline void lowpan_push_hc_data(u8 **hc_ptr, const void *data,
*hc_ptr += len;
}
+static inline u8 lowpan_addr_mode_size(const u8 addr_mode)
+{
+ static const u8 addr_sizes[] = {
+ [LOWPAN_IPHC_ADDR_00] = 16,
+ [LOWPAN_IPHC_ADDR_01] = 8,
+ [LOWPAN_IPHC_ADDR_02] = 2,
+ [LOWPAN_IPHC_ADDR_03] = 0,
+ };
+ return addr_sizes[addr_mode];
+}
+
+static inline u8 lowpan_next_hdr_size(const u8 h_enc, u16 *uncomp_header)
+{
+ u8 ret = 1;
+
+ if ((h_enc & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) {
+ *uncomp_header += sizeof(struct udphdr);
+
+ switch (h_enc & LOWPAN_NHC_UDP_CS_P_11) {
+ case LOWPAN_NHC_UDP_CS_P_00:
+ ret += 4;
+ break;
+ case LOWPAN_NHC_UDP_CS_P_01:
+ case LOWPAN_NHC_UDP_CS_P_10:
+ ret += 3;
+ break;
+ case LOWPAN_NHC_UDP_CS_P_11:
+ ret++;
+ break;
+ default:
+ break;
+ }
+
+ if (!(h_enc & LOWPAN_NHC_UDP_CS_C))
+ ret += 2;
+ }
+
+ return ret;
+}
+
+/**
+ * lowpan_uncompress_size - returns skb->len size with uncompressed header
+ * @skb: sk_buff with 6lowpan header inside
+ * @datagram_offset: optional to get the datagram_offset value
+ *
+ * Returns the skb->len with uncompressed header
+ */
+static inline u16
+lowpan_uncompress_size(const struct sk_buff *skb, u16 *dgram_offset)
+{
+ u16 ret = 2, uncomp_header = sizeof(struct ipv6hdr);
+ u8 iphc0, iphc1, h_enc;
+
+ iphc0 = skb_network_header(skb)[0];
+ iphc1 = skb_network_header(skb)[1];
+
+ switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) {
+ case 0:
+ ret += 4;
+ break;
+ case 1:
+ ret += 3;
+ break;
+ case 2:
+ ret++;
+ break;
+ default:
+ break;
+ }
+
+ if (!(iphc0 & LOWPAN_IPHC_NH_C))
+ ret++;
+
+ if (!(iphc0 & 0x03))
+ ret++;
+
+ ret += lowpan_addr_mode_size((iphc1 & LOWPAN_IPHC_SAM) >>
+ LOWPAN_IPHC_SAM_BIT);
+
+ if (iphc1 & LOWPAN_IPHC_M) {
+ switch ((iphc1 & LOWPAN_IPHC_DAM_11) >>
+ LOWPAN_IPHC_DAM_BIT) {
+ case LOWPAN_IPHC_DAM_00:
+ ret += 16;
+ break;
+ case LOWPAN_IPHC_DAM_01:
+ ret += 6;
+ break;
+ case LOWPAN_IPHC_DAM_10:
+ ret += 4;
+ break;
+ case LOWPAN_IPHC_DAM_11:
+ ret++;
+ break;
+ default:
+ break;
+ }
+ } else {
+ ret += lowpan_addr_mode_size((iphc1 & LOWPAN_IPHC_DAM_11) >>
+ LOWPAN_IPHC_DAM_BIT);
+ }
+
+ if (iphc0 & LOWPAN_IPHC_NH_C) {
+ h_enc = skb_network_header(skb)[ret];
+ ret += lowpan_next_hdr_size(h_enc, &uncomp_header);
+ }
+
+ if (dgram_offset)
+ *dgram_offset = uncomp_header;
+
+ return skb->len + uncomp_header - ret;
+}
+
typedef int (*skb_delivery_cb)(struct sk_buff *skb, struct net_device *dev);
int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
--
1.9.0
--
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