This patch provides a set of structures to represent 802.15.4 MAC headers, and a set of operations to push/pull/peek these structs from skbs. We cannot simply pointer-cast the skb MAC header pointer to these structs, because 802.15.4 headers are wildly variable - depending on the first three bytes, virtually all other fields of the header may be present or not, and be present with different lengths.
The new header creation/parsing routines also support 802.15.4 security headers, which are currently not supported by the mac802154 implementation of the protocol. Signed-off-by: Phoebe Buckheister <phoebe.buckheis...@itwm.fraunhofer.de> --- include/net/ieee802154.h | 28 +++- include/net/ieee802154_netdev.h | 87 ++++++++++++ include/net/mac802154.h | 1 + net/ieee802154/Makefile | 3 +- net/ieee802154/header_ops.c | 287 +++++++++++++++++++++++++++++++++++++++ 5 files changed, 401 insertions(+), 5 deletions(-) create mode 100644 net/ieee802154/header_ops.c diff --git a/include/net/ieee802154.h b/include/net/ieee802154.h index ee59f8b..c7ae0ac 100644 --- a/include/net/ieee802154.h +++ b/include/net/ieee802154.h @@ -42,22 +42,42 @@ (((x) << IEEE802154_FC_TYPE_SHIFT) & IEEE802154_FC_TYPE_MASK)); \ } while (0) -#define IEEE802154_FC_SECEN (1 << 3) -#define IEEE802154_FC_FRPEND (1 << 4) -#define IEEE802154_FC_ACK_REQ (1 << 5) -#define IEEE802154_FC_INTRA_PAN (1 << 6) +#define IEEE802154_FC_SECEN_SHIFT 3 +#define IEEE802154_FC_SECEN (1 << IEEE802154_FC_SECEN_SHIFT) +#define IEEE802154_FC_FRPEND_SHIFT 4 +#define IEEE802154_FC_FRPEND (1 << IEEE802154_FC_FRPEND_SHIFT) +#define IEEE802154_FC_ACK_REQ_SHIFT 5 +#define IEEE802154_FC_ACK_REQ (1 << IEEE802154_FC_ACK_REQ_SHIFT) +#define IEEE802154_FC_INTRA_PAN_SHIFT 6 +#define IEEE802154_FC_INTRA_PAN (1 << IEEE802154_FC_INTRA_PAN_SHIFT) #define IEEE802154_FC_SAMODE_SHIFT 14 #define IEEE802154_FC_SAMODE_MASK (3 << IEEE802154_FC_SAMODE_SHIFT) #define IEEE802154_FC_DAMODE_SHIFT 10 #define IEEE802154_FC_DAMODE_MASK (3 << IEEE802154_FC_DAMODE_SHIFT) +#define IEEE802154_FC_VERSION_SHIFT 12 +#define IEEE802154_FC_VERSION_MASK (3 << IEEE802154_FC_VERSION_SHIFT) +#define IEEE802154_FC_VERSION(x) ((x & IEEE802154_FC_VERSION_MASK) >> IEEE802154_FC_VERSION_SHIFT) + #define IEEE802154_FC_SAMODE(x) \ (((x) & IEEE802154_FC_SAMODE_MASK) >> IEEE802154_FC_SAMODE_SHIFT) #define IEEE802154_FC_DAMODE(x) \ (((x) & IEEE802154_FC_DAMODE_MASK) >> IEEE802154_FC_DAMODE_SHIFT) +#define IEEE802154_SCF_SECLEVEL_MASK 7 +#define IEEE802154_SCF_SECLEVEL_SHIFT 0 +#define IEEE802154_SCF_SECLEVEL(x) (x & IEEE802154_SCF_SECLEVEL_MASK) +#define IEEE802154_SCF_KEY_ID_MODE_SHIFT 3 +#define IEEE802154_SCF_KEY_ID_MODE_MASK (3 << IEEE802154_SCF_KEY_ID_MODE_SHIFT) +#define IEEE802154_SCF_KEY_ID_MODE(x) \ + ((x & IEEE802154_SCF_KEY_ID_MODE_MASK) >> IEEE802154_SCF_KEY_ID_MODE_SHIFT) + +#define IEEE802154_SCF_KEY_IMPLICIT 0 +#define IEEE802154_SCF_KEY_INDEX 1 +#define IEEE802154_SCF_KEY_SHORT_INDEX 2 +#define IEEE802154_SCF_KEY_HW_INDEX 3 /* MAC footer size */ #define IEEE802154_MFR_SIZE 2 /* 2 octets */ diff --git a/include/net/ieee802154_netdev.h b/include/net/ieee802154_netdev.h index e4810d5..c3fc33a 100644 --- a/include/net/ieee802154_netdev.h +++ b/include/net/ieee802154_netdev.h @@ -28,6 +28,28 @@ #define IEEE802154_NETDEVICE_H #include <net/af_ieee802154.h> +#include <linux/netdevice.h> +#include <linux/skbuff.h> + +struct ieee802154_sechdr { +#if defined(__LITTLE_ENDIAN_BITFIELD) + u8 level:3, + key_id_mode:2, + reserved:3; +#elif defined(__BIG_ENDIAN_BITFIELD) + u8 reserved:3, + key_id_mode:2, + level:3; +#else +#error "Please fix <asm/byteorder.h>" +#endif + u8 key_id; + __le32 frame_counter; + union { + __le32 short_src; + __le64 extended_src; + }; +}; struct ieee802154_addr { u8 mode; @@ -38,6 +60,71 @@ struct ieee802154_addr { }; }; +struct ieee802154_hdr_fc { +#if defined(__LITTLE_ENDIAN_BITFIELD) + u16 type:3, + security_enabled:1, + frame_pending:1, + ack_request:1, + intra_pan:1, + reserved:3, + dest_addr_mode:2, + version:2, + source_addr_mode:2; +#elif defined(__BIG_ENDIAN_BITFIELD) + u16 reserved:1, + intra_pan:1, + ack_request:1, + frame_pending:1, + security_enabled:1, + type:3, + source_addr_mode:2, + version:2, + dest_addr_mode:2, + reserved2:2; +#else +#error "Please fix <asm/byteorder.h>" +#endif +}; + +struct ieee802154_hdr { + struct ieee802154_hdr_fc fc; + u8 seq; + struct ieee802154_addr source; + struct ieee802154_addr dest; + struct ieee802154_sechdr sec; +}; + +/* pushes hdr onto the skb. fields of hdr->fc that can be calculated from + * the contents of hdr will be, and the actual value of those bits in + * hdr->fc will be ignored. this includes the INTRA_PAN bit and the frame + * version, if SECEN is set. + */ +int ieee802154_hdr_push(struct sk_buff *skb, const struct ieee802154_hdr *hdr); + +/* pulls the entire 802.15.4 header off of the skb, including the security + * header, and performs pan id decompression + */ +int ieee802154_hdr_pull(struct sk_buff *skb, struct ieee802154_hdr *hdr); + +/* parses the frame control, sequence number of address fields in a given skb + * and stores them into hdr, performing pan id decompression and length checks + * to be suitable for use in header_ops.parse + */ +int ieee802154_hdr_peek_addrs(const struct sk_buff *skb, + struct ieee802154_hdr *hdr); + +static inline int ieee802154_hdr_length(struct sk_buff *skb) +{ + struct ieee802154_hdr hdr; + int len = ieee802154_hdr_pull(skb, &hdr); + + if (len > 0) + skb_push(skb, len); + + return len; +} + static inline bool ieee802154_addr_equal(const struct ieee802154_addr *a1, const struct ieee802154_addr *a2) { diff --git a/include/net/mac802154.h b/include/net/mac802154.h index f74b2a8..a591053 100644 --- a/include/net/mac802154.h +++ b/include/net/mac802154.h @@ -20,6 +20,7 @@ #define NET_MAC802154_H #include <net/af_ieee802154.h> +#include <linux/skbuff.h> /* General MAC frame format: * 2 bytes: Frame Control diff --git a/net/ieee802154/Makefile b/net/ieee802154/Makefile index 78b1fa2..bf1b514 100644 --- a/net/ieee802154/Makefile +++ b/net/ieee802154/Makefile @@ -3,7 +3,8 @@ obj-$(CONFIG_IEEE802154_6LOWPAN) += 6lowpan.o obj-$(CONFIG_6LOWPAN_IPHC) += 6lowpan_iphc.o 6lowpan-y := 6lowpan_rtnl.o reassembly.o -ieee802154-y := netlink.o nl-mac.o nl-phy.o nl_policy.o wpan-class.o +ieee802154-y := netlink.o nl-mac.o nl-phy.o nl_policy.o wpan-class.o \ + header_ops.o af_802154-y := af_ieee802154.o raw.o dgram.o ccflags-y += -D__CHECK_ENDIAN__ diff --git a/net/ieee802154/header_ops.c b/net/ieee802154/header_ops.c new file mode 100644 index 0000000..bed42a4 --- /dev/null +++ b/net/ieee802154/header_ops.c @@ -0,0 +1,287 @@ +/* + * Copyright (C) 2014 Fraunhofer ITWM + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * Written by: + * Phoebe Buckheister <phoebe.buckheis...@itwm.fraunhofer.de> + */ + +#include <net/mac802154.h> +#include <net/ieee802154.h> +#include <net/ieee802154_netdev.h> + +static int +ieee802154_hdr_push_addr(u8 *buf, const struct ieee802154_addr *addr, + bool omit_pan) +{ + int pos = 0; + + if (addr->mode == IEEE802154_ADDR_NONE) + return 0; + + if (!omit_pan) { + memcpy(buf + pos, &addr->pan_id, 2); + pos += 2; + } + + switch (addr->mode) { + case IEEE802154_ADDR_SHORT: + memcpy(buf + pos, &addr->short_addr, 2); + pos += 2; + break; + + case IEEE802154_ADDR_LONG: + memcpy(buf + pos, &addr->extended_addr, IEEE802154_ADDR_LEN); + pos += IEEE802154_ADDR_LEN; + break; + + default: + return -EINVAL; + } + + return pos; +} + +static int +ieee802154_hdr_push_sechdr(u8 *buf, const struct ieee802154_sechdr *hdr) +{ + int pos = 5; + + memcpy(buf, hdr, 1); + memcpy(buf + 1, &hdr->frame_counter, 4); + + switch (hdr->key_id_mode) { + case IEEE802154_SCF_KEY_IMPLICIT: + return pos; + + case IEEE802154_SCF_KEY_INDEX: + break; + + case IEEE802154_SCF_KEY_SHORT_INDEX: + memcpy(buf + pos, &hdr->short_src, 4); + pos += 4; + break; + + case IEEE802154_SCF_KEY_HW_INDEX: + memcpy(buf + pos, &hdr->extended_src, IEEE802154_ADDR_LEN); + pos += IEEE802154_ADDR_LEN; + break; + } + + buf[pos++] = hdr->key_id; + + return pos; +} + +int +ieee802154_hdr_push(struct sk_buff *skb, const struct ieee802154_hdr *hdr) +{ + u8 buf[MAC802154_FRAME_HARD_HEADER_LEN]; + int pos = 2; + int rc; + struct ieee802154_hdr_fc fc = hdr->fc; + + buf[pos++] = hdr->seq; + + fc.dest_addr_mode = hdr->dest.mode; + + rc = ieee802154_hdr_push_addr(buf + pos, &hdr->dest, false); + if (rc < 0) + return -EINVAL; + pos += rc; + + fc.source_addr_mode = hdr->source.mode; + + if (hdr->source.pan_id == hdr->dest.pan_id && + hdr->dest.mode != IEEE802154_ADDR_NONE) + fc.intra_pan = true; + + rc = ieee802154_hdr_push_addr(buf + pos, &hdr->source, fc.intra_pan); + if (rc < 0) + return -EINVAL; + pos += rc; + + if (fc.security_enabled) { + fc.version = 1; + + rc = ieee802154_hdr_push_sechdr(buf + pos, &hdr->sec); + if (rc < 0) + return -EINVAL; + + pos += rc; + } + + memcpy(buf, &fc, 2); + + memcpy(skb_push(skb, pos), buf, pos); + + return pos; +} +EXPORT_SYMBOL_GPL(ieee802154_hdr_push); + +static int +ieee802154_hdr_get_addr(const u8 *buf, int mode, bool omit_pan, + struct ieee802154_addr *addr) +{ + int pos = 0; + + addr->mode = mode; + + if (mode == IEEE802154_ADDR_NONE) + return 0; + + if (!omit_pan) { + memcpy(&addr->pan_id, buf + pos, 2); + pos += 2; + } + + if (mode == IEEE802154_ADDR_SHORT) { + memcpy(&addr->short_addr, buf + pos, 2); + return pos + 2; + } else { + memcpy(&addr->extended_addr, buf + pos, IEEE802154_ADDR_LEN); + return pos + IEEE802154_ADDR_LEN; + } +} + +static int ieee802154_hdr_addr_len(int mode, bool omit_pan) +{ + int pan_len = omit_pan ? 0 : 2; + + switch (mode) { + case IEEE802154_ADDR_NONE: return 0; + case IEEE802154_ADDR_SHORT: return 2 + pan_len; + case IEEE802154_ADDR_LONG: return IEEE802154_ADDR_LEN + pan_len; + default: return -EINVAL; + } +} + +static int +ieee802154_hdr_get_sechdr(const u8 *buf, struct ieee802154_sechdr *hdr) +{ + int pos = 5; + + memcpy(hdr, buf, 1); + memcpy(&hdr->frame_counter, buf + 1, 4); + + switch (hdr->key_id_mode) { + case IEEE802154_SCF_KEY_IMPLICIT: + return pos; + + case IEEE802154_SCF_KEY_INDEX: + break; + + case IEEE802154_SCF_KEY_SHORT_INDEX: + memcpy(&hdr->short_src, buf + pos, 4); + pos += 4; + break; + + case IEEE802154_SCF_KEY_HW_INDEX: + memcpy(&hdr->extended_src, buf + pos, IEEE802154_ADDR_LEN); + pos += IEEE802154_ADDR_LEN; + break; + } + + hdr->key_id = buf[pos++]; + + return pos; +} + +static int ieee802154_hdr_sechdr_len(u8 sc) +{ + switch (IEEE802154_SCF_KEY_ID_MODE(sc)) { + case IEEE802154_SCF_KEY_IMPLICIT: return 5; + case IEEE802154_SCF_KEY_INDEX: return 6; + case IEEE802154_SCF_KEY_SHORT_INDEX: return 10; + case IEEE802154_SCF_KEY_HW_INDEX: return 14; + default: return -EINVAL; + } +} + +static int ieee802154_hdr_minlen(const struct ieee802154_hdr *hdr) +{ + int dlen, slen; + + dlen = ieee802154_hdr_addr_len(hdr->fc.dest_addr_mode, false); + slen = ieee802154_hdr_addr_len(hdr->fc.source_addr_mode, + hdr->fc.intra_pan); + + if (slen < 0 || dlen < 0) + return -EINVAL; + + return 3 + dlen + slen + hdr->fc.security_enabled; +} + +static int +ieee802154_hdr_get_addrs(const u8 *buf, struct ieee802154_hdr *hdr) +{ + int pos = 0; + + pos += ieee802154_hdr_get_addr(buf + pos, hdr->fc.dest_addr_mode, + false, &hdr->dest); + pos += ieee802154_hdr_get_addr(buf + pos, hdr->fc.source_addr_mode, + hdr->fc.intra_pan, &hdr->source); + + if (hdr->fc.intra_pan) + hdr->source.pan_id = hdr->dest.pan_id; + + return pos; +} + +int +ieee802154_hdr_pull(struct sk_buff *skb, struct ieee802154_hdr *hdr) +{ + int pos = 3, rc; + + if (!pskb_may_pull(skb, 3)) + return -EINVAL; + + memcpy(hdr, skb->data, 3); + + rc = ieee802154_hdr_minlen(hdr); + if (rc < 0 || !pskb_may_pull(skb, rc)) + return -EINVAL; + + pos += ieee802154_hdr_get_addrs(skb->data + pos, hdr); + + if (hdr->fc.security_enabled) { + int want = pos + ieee802154_hdr_sechdr_len(skb->data[pos]); + + if (!pskb_may_pull(skb, want)) + return -EINVAL; + + pos += ieee802154_hdr_get_sechdr(skb->data + pos, &hdr->sec); + } + + skb_pull(skb, pos); + return pos; +} +EXPORT_SYMBOL_GPL(ieee802154_hdr_pull); + +int +ieee802154_hdr_peek_addrs(const struct sk_buff *skb, struct ieee802154_hdr *hdr) +{ + const u8 *buf = skb_mac_header(skb); + int pos = 3, rc; + + if (buf + 3 > skb_tail_pointer(skb)) + return -EINVAL; + + memcpy(hdr, buf, 3); + + rc = ieee802154_hdr_minlen(hdr); + if (rc < 0 || buf + rc > skb_tail_pointer(skb)) + return -EINVAL; + + pos += ieee802154_hdr_get_addrs(buf + pos, hdr); + return pos; +} +EXPORT_SYMBOL_GPL(ieee802154_hdr_peek_addrs); -- 1.7.9.5 ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. 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