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| author | Alexander Aring <alex.aring@gmail.com> | 2014-02-28 10:32:44 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-03-01 02:05:21 +0400 |
| commit | 349aa7bc29ee2469f94bba97bb1c9c270fffa215 (patch) | |
| tree | cee402f26c9137467bd46513a626c69bd0310e18 /net/ieee802154 | |
| parent | 89745c9c41b093e4041f290343e8916f74f26051 (diff) | |
| download | linux-349aa7bc29ee2469f94bba97bb1c9c270fffa215.tar.xz | |
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@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ieee802154')
| -rw-r--r-- | net/ieee802154/6lowpan.h | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/net/ieee802154/6lowpan.h b/net/ieee802154/6lowpan.h index 2b835db3bda8..0dccf62434d5 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, |