Subject: Re: [PATCHv2 bluetooth-next 10/10] 6lowpan: add support for 802.15.4 short addr handling

From: Stefan Schmidt <[email-masked]>
Date: Wed, 4 May 2016 14:23:43 +0200

Hello.

On 20/04/16 10:19, Alexander Aring wrote:
> This patch adds necessary handling for use the short address for
> 802.15.4 6lowpan. It contains support for IPHC address compression
> and new matching algorithmn to decide which link layer address will be
> used for 802.15.4 frame.
>
> Signed-off-by: Alexander Aring<[email-masked]>
> ---
>   net/6lowpan/iphc.c          | 167 ++++++++++++++++++++++++++++++++++++--------
>   net/ieee802154/6lowpan/tx.c | 107 ++++++++++++++--------------
>   2 files changed, 189 insertions(+), 85 deletions(-)
>
> diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
> index 8501dd5..aca38dc 100644
> --- a/net/6lowpan/iphc.c
> +++ b/net/6lowpan/iphc.c
> @@ -761,22 +761,75 @@ static const u8 lowpan_iphc_dam_to_sam_value[] = {
>   	[LOWPAN_IPHC_DAM_11] = LOWPAN_IPHC_SAM_11,
>   };
>   
> -static u8 lowpan_compress_ctx_addr(u8 **hc_ptr, const struct in6_addr *ipaddr,
> +static inline bool
> +lowpan_iphc_compress_ctx_802154_lladdr(const struct in6_addr *ipaddr,
> +				       const struct lowpan_iphc_ctx *ctx,
> +				       const void *lladdr)
> +{
> +	const struct ieee802154_addr *addr = lladdr;
> +	unsigned char extended_addr[EUI64_ADDR_LEN];
> +	struct in6_addr tmp = {};
> +	bool lladdr_compress = false;
> +
> +	switch (addr->mode) {
> +	case IEEE802154_ADDR_LONG:
> +		ieee802154_le64_to_be64(&extended_addr, &addr->extended_addr);
> +		/* check for SAM/DAM = 11 */
> +		memcpy(&tmp.s6_addr[8], &extended_addr, EUI64_ADDR_LEN);
> +		/* second bit-flip (Universe/Local) is done according RFC2464 */
> +		tmp.s6_addr[8] ^= 0x02;
> +		/* context information are always used */
> +		ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
> +		if (ipv6_addr_equal(&tmp, ipaddr))
> +			lladdr_compress = true;
> +		break;
> +	case IEEE802154_ADDR_SHORT:
> +		tmp.s6_addr[11] = 0xFF;
> +		tmp.s6_addr[12] = 0xFE;
> +		ieee802154_le16_to_be16(&tmp.s6_addr16[7],
> +					&addr->short_addr);
> +		/* context information are always used */
> +		ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
> +		if (ipv6_addr_equal(&tmp, ipaddr))
> +			lladdr_compress = true;
> +		break;
> +	default:
> +		/* should never handled and filtered by 802154 6lowpan */
> +		WARN_ON_ONCE(1);
> +		break;
> +	}
> +
> +	return lladdr_compress;
> +}
> +
> +static u8 lowpan_compress_ctx_addr(u8 **hc_ptr, const struct net_device *dev,
> +				   const struct in6_addr *ipaddr,
>   				   const struct lowpan_iphc_ctx *ctx,
>   				   const unsigned char *lladdr, bool sam)
>   {
>   	struct in6_addr tmp = {};
>   	u8 dam;
>   
> -	/* check for SAM/DAM = 11 */
> -	memcpy(&tmp.s6_addr[8], lladdr, 8);
> -	/* second bit-flip (Universe/Local) is done according RFC2464 */
> -	tmp.s6_addr[8] ^= 0x02;
> -	/* context information are always used */
> -	ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
> -	if (ipv6_addr_equal(&tmp, ipaddr)) {
> -		dam = LOWPAN_IPHC_DAM_11;
> -		goto out;
> +	switch (lowpan_dev(dev)->lltype) {
> +	case LOWPAN_LLTYPE_IEEE802154:
> +		if (lowpan_iphc_compress_ctx_802154_lladdr(ipaddr, ctx,
> +							   lladdr)) {
> +			dam = LOWPAN_IPHC_DAM_11;
> +			goto out;
> +		}
> +		break;
> +	default:
> +		/* check for SAM/DAM = 11 */
> +		memcpy(&tmp.s6_addr[8], lladdr, EUI64_ADDR_LEN);
> +		/* second bit-flip (Universe/Local) is done according RFC2464 */
> +		tmp.s6_addr[8] ^= 0x02;
> +		/* context information are always used */
> +		ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
> +		if (ipv6_addr_equal(&tmp, ipaddr)) {
> +			dam = LOWPAN_IPHC_DAM_11;
> +			goto out;
> +		}
> +		break;
>   	}
>   
>   	memset(&tmp, 0, sizeof(tmp));
> @@ -813,28 +866,85 @@ out:
>   		return dam;
>   }
>   
> -static u8 lowpan_compress_addr_64(u8 **hc_ptr, const struct in6_addr *ipaddr,
> +static inline bool
> +lowpan_iphc_compress_802154_lladdr(const struct in6_addr *ipaddr,
> +				   const void *lladdr)
> +{
> +	const struct ieee802154_addr *addr = lladdr;
> +	unsigned char extended_addr[EUI64_ADDR_LEN];
> +	struct in6_addr tmp = {};
> +	bool lladdr_compress = false;
> +
> +	switch (addr->mode) {
> +	case IEEE802154_ADDR_LONG:
> +		ieee802154_le64_to_be64(&extended_addr, &addr->extended_addr);
> +		if (is_addr_mac_addr_based(ipaddr, extended_addr))
> +			lladdr_compress = true;
> +		break;
> +	case IEEE802154_ADDR_SHORT:
> +		/* fe:80::ff:fe00:XXXX
> +		 *                \__/
> +		 *             short_addr
> +		 *
> +		 * Universe/Local bit is zero.
> +		 */
> +		tmp.s6_addr[0] = 0xFE;
> +		tmp.s6_addr[1] = 0x80;
> +		tmp.s6_addr[11] = 0xFF;
> +		tmp.s6_addr[12] = 0xFE;
> +		ieee802154_le16_to_be16(&tmp.s6_addr16[7],
> +					&addr->short_addr);
> +		if (ipv6_addr_equal(&tmp, ipaddr))
> +			lladdr_compress = true;
> +		break;
> +	default:
> +		/* should never handled and filtered by 802154 6lowpan */
> +		WARN_ON_ONCE(1);
> +		break;
> +	}
> +
> +	return lladdr_compress;
> +}
> +
> +static u8 lowpan_compress_addr_64(u8 **hc_ptr, const struct net_device *dev,
> +				  const struct in6_addr *ipaddr,
>   				  const unsigned char *lladdr, bool sam)
>   {
> -	u8 dam = LOWPAN_IPHC_DAM_00;
> +	u8 dam = LOWPAN_IPHC_DAM_01;
>   
> -	if (is_addr_mac_addr_based(ipaddr, lladdr)) {
> -		dam = LOWPAN_IPHC_DAM_11; /* 0-bits */
> -		pr_debug("address compression 0 bits\n");
> -	} else if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
> +	switch (lowpan_dev(dev)->lltype) {
> +	case LOWPAN_LLTYPE_IEEE802154:
> +		if (lowpan_iphc_compress_802154_lladdr(ipaddr, lladdr)) {
> +			dam = LOWPAN_IPHC_DAM_11; /* 0-bits */
> +			pr_debug("address compression 0 bits\n");
> +			goto out;
> +		}
> +		break;
> +	default:
> +		if (is_addr_mac_addr_based(ipaddr, lladdr)) {
> +			dam = LOWPAN_IPHC_DAM_11; /* 0-bits */
> +			pr_debug("address compression 0 bits\n");
> +			goto out;
> +		}
> +		break;
> +	}
> +
> +	if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
>   		/* compress IID to 16 bits xxxx::XXXX */
>   		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[7], 2);
>   		dam = LOWPAN_IPHC_DAM_10; /* 16-bits */
>   		raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)",
>   				*hc_ptr - 2, 2);
> -	} else {
> -		/* do not compress IID => xxxx::IID */
> -		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8);
> -		dam = LOWPAN_IPHC_DAM_01; /* 64-bits */
> -		raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
> -				*hc_ptr - 8, 8);
> +		goto out;
>   	}
>   
> +	/* do not compress IID => xxxx::IID */
> +	lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8);
> +	raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
> +			*hc_ptr - 8, 8);
> +
> +out:
> +
>   	if (sam)
>   		return lowpan_iphc_dam_to_sam_value[dam];
>   	else
> @@ -1013,9 +1123,6 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
>   	iphc0 = LOWPAN_DISPATCH_IPHC;
>   	iphc1 = 0;
>   
> -	raw_dump_inline(__func__, "saddr", saddr, EUI64_ADDR_LEN);
> -	raw_dump_inline(__func__, "daddr", daddr, EUI64_ADDR_LEN);
> -
>   	raw_dump_table(__func__, "sending raw skb network uncompressed packet",
>   		       skb->data, skb->len);
>   
> @@ -1088,14 +1195,15 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
>   		iphc1 |= LOWPAN_IPHC_SAC;
>   	} else {
>   		if (sci) {
> -			iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, &hdr->saddr,
> +			iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, dev,
> +							  &hdr->saddr,
>   							  &sci_entry, saddr,
>   							  true);
>   			iphc1 |= LOWPAN_IPHC_SAC;
>   		} else {
>   			if (ipv6_saddr_type & IPV6_ADDR_LINKLOCAL &&
>   			    lowpan_is_linklocal_zero_padded(hdr->saddr)) {
> -				iphc1 |= lowpan_compress_addr_64(&hc_ptr,
> +				iphc1 |= lowpan_compress_addr_64(&hc_ptr, dev,
>   								 &hdr->saddr,
>   								 saddr, true);
>   				pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
> @@ -1123,14 +1231,15 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
>   		}
>   	} else {
>   		if (dci) {
> -			iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, &hdr->daddr,
> +			iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, dev,
> +							  &hdr->daddr,
>   							  &dci_entry, daddr,
>   							  false);
>   			iphc1 |= LOWPAN_IPHC_DAC;
>   		} else {
>   			if (ipv6_daddr_type & IPV6_ADDR_LINKLOCAL &&
>   			    lowpan_is_linklocal_zero_padded(hdr->daddr)) {
> -				iphc1 |= lowpan_compress_addr_64(&hc_ptr,
> +				iphc1 |= lowpan_compress_addr_64(&hc_ptr, dev,
>   								 &hdr->daddr,
>   								 daddr, false);
>   				pr_debug("dest address unicast link-local %pI6c iphc1 0x%02x\n",
> diff --git a/net/ieee802154/6lowpan/tx.c b/net/ieee802154/6lowpan/tx.c
> index e459afd..88c9d16 100644
> --- a/net/ieee802154/6lowpan/tx.c
> +++ b/net/ieee802154/6lowpan/tx.c
> @@ -9,6 +9,7 @@
>    */
>   
>   #include <net/6lowpan.h>
> +#include <net/ndisc.h>
>   #include <net/ieee802154_netdev.h>
>   #include <net/mac802154.h>
>   
> @@ -17,19 +18,9 @@
>   #define LOWPAN_FRAG1_HEAD_SIZE	0x4
>   #define LOWPAN_FRAGN_HEAD_SIZE	0x5
>   
> -/* don't save pan id, it's intra pan */
> -struct lowpan_addr {
> -	u8 mode;
> -	union {
> -		/* IPv6 needs big endian here */
> -		__be64 extended_addr;
> -		__be16 short_addr;
> -	} u;
> -};
> -
>   struct lowpan_addr_info {
> -	struct lowpan_addr daddr;
> -	struct lowpan_addr saddr;
> +	struct ieee802154_addr daddr;
> +	struct ieee802154_addr saddr;
>   };
>   
>   static inline struct
> @@ -48,12 +39,14 @@ lowpan_addr_info *lowpan_skb_priv(const struct sk_buff *skb)
>    * RAW/DGRAM sockets.
>    */
>   int lowpan_header_create(struct sk_buff *skb, struct net_device *ldev,
> -			 unsigned short type, const void *_daddr,
> -			 const void *_saddr, unsigned int len)
> +			 unsigned short type, const void *daddr,
> +			 const void *saddr, unsigned int len)
>   {
> -	const u8 *saddr = _saddr;
> -	const u8 *daddr = _daddr;
> -	struct lowpan_addr_info *info;
> +	struct wpan_dev *wpan_dev = lowpan_802154_dev(ldev)->wdev->ieee802154_ptr;
> +	struct lowpan_addr_info *info = lowpan_skb_priv(skb);
> +	struct lowpan_802154_neigh *llneigh = NULL;
> +	const struct ipv6hdr *hdr = ipv6_hdr(skb);
> +	struct neighbour *n;
>   
>   	/* TODO:
>   	 * if this package isn't ipv6 one, where should it be routed?
> @@ -61,21 +54,44 @@ int lowpan_header_create(struct sk_buff *skb, struct net_device *ldev,
>   	if (type != ETH_P_IPV6)
>   		return 0;
>   
> -	if (!saddr)
> -		saddr = ldev->dev_addr;
> +	/* intra-pan communication */
> +	info->saddr.pan_id = wpan_dev->pan_id;
> +	info->daddr.pan_id = info->saddr.pan_id;
>   
> -	raw_dump_inline(__func__, "saddr", (unsigned char *)saddr, 8);
> -	raw_dump_inline(__func__, "daddr", (unsigned char *)daddr, 8);
> +	if (!memcmp(daddr, ldev->broadcast, EUI64_ADDR_LEN)) {
> +		info->daddr.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
> +		info->daddr.mode = IEEE802154_ADDR_SHORT;
> +	} else {
> +		n = neigh_lookup(&nd_tbl, &hdr->daddr, ldev);
> +		if (n)
> +			llneigh = lowpan_802154_neigh(neighbour_priv(n));
> +
> +		if (llneigh &&
> +		    ieee802154_is_valid_src_short_addr(llneigh->short_addr)) {
> +			info->daddr.mode = IEEE802154_ADDR_SHORT;
> +			info->daddr.short_addr = llneigh->short_addr;
> +		} else {
> +			info->daddr.mode = IEEE802154_ADDR_LONG;
> +			ieee802154_be64_to_le64(&info->daddr.extended_addr,
> +						daddr);
> +		}
>   
> -	info = lowpan_skb_priv(skb);
> +		if (n)
> +			neigh_release(n);
> +	}
>   
> -	/* TODO: Currently we only support extended_addr */
> -	info->daddr.mode = IEEE802154_ADDR_LONG;
> -	memcpy(&info->daddr.u.extended_addr, daddr,
> -	       sizeof(info->daddr.u.extended_addr));
> -	info->saddr.mode = IEEE802154_ADDR_LONG;
> -	memcpy(&info->saddr.u.extended_addr, saddr,
> -	       sizeof(info->daddr.u.extended_addr));
> +	if (!saddr) {
> +		if (ieee802154_is_valid_src_short_addr(wpan_dev->short_addr)) {
> +			info->saddr.mode = IEEE802154_ADDR_SHORT;
> +			info->saddr.short_addr = wpan_dev->short_addr;
> +		} else {
> +			info->saddr.mode = IEEE802154_ADDR_LONG;
> +			info->saddr.extended_addr = wpan_dev->extended_addr;
> +		}
> +	} else {
> +		info->saddr.mode = IEEE802154_ADDR_LONG;
> +		ieee802154_be64_to_le64(&info->saddr.extended_addr, saddr);
> +	}
>   
>   	return 0;
>   }
> @@ -209,47 +225,26 @@ static int lowpan_header(struct sk_buff *skb, struct net_device *ldev,
>   			 u16 *dgram_size, u16 *dgram_offset)
>   {
>   	struct wpan_dev *wpan_dev = lowpan_802154_dev(ldev)->wdev->ieee802154_ptr;
> -	struct ieee802154_addr sa, da;
>   	struct ieee802154_mac_cb *cb = mac_cb_init(skb);
>   	struct lowpan_addr_info info;
> -	void *daddr, *saddr;
>   
>   	memcpy(&info, lowpan_skb_priv(skb), sizeof(info));
>   
> -	/* TODO: Currently we only support extended_addr */
> -	daddr = &info.daddr.u.extended_addr;
> -	saddr = &info.saddr.u.extended_addr;
> -
>   	*dgram_size = skb->len;
> -	lowpan_header_compress(skb, ldev, daddr, saddr);
> +	lowpan_header_compress(skb, ldev, &info.daddr, &info.saddr);
>   	/* dgram_offset = (saved bytes after compression) + lowpan header len */
>   	*dgram_offset = (*dgram_size - skb->len) + skb_network_header_len(skb);
>   
>   	cb->type = IEEE802154_FC_TYPE_DATA;
>   
> -	/* prepare wpan address data */
> -	sa.mode = IEEE802154_ADDR_LONG;
> -	sa.pan_id = wpan_dev->pan_id;
> -	sa.extended_addr = ieee802154_devaddr_from_raw(saddr);
> -
> -	/* intra-PAN communications */
> -	da.pan_id = sa.pan_id;
> -
> -	/* if the destination address is the broadcast address, use the
> -	 * corresponding short address
> -	 */
> -	if (!memcmp(daddr, ldev->broadcast, EUI64_ADDR_LEN)) {
> -		da.mode = IEEE802154_ADDR_SHORT;
> -		da.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
> +	if (info.daddr.mode == IEEE802154_ADDR_SHORT &&
> +	    ieee802154_is_broadcast_short_addr(info.daddr.short_addr))
>   		cb->ackreq = false;
> -	} else {
> -		da.mode = IEEE802154_ADDR_LONG;
> -		da.extended_addr = ieee802154_devaddr_from_raw(daddr);
> +	else
>   		cb->ackreq = wpan_dev->ackreq;
> -	}
>   
> -	return wpan_dev_hard_header(skb, lowpan_802154_dev(ldev)->wdev, &da,
> -				    &sa, 0);
> +	return wpan_dev_hard_header(skb, lowpan_802154_dev(ldev)->wdev,
> +				    &info.daddr, &info.saddr, 0);
>   }
>   
>   netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *ldev)

Reviewed-by: Stefan Schmidt<[email-masked]>

regards
Stefan Schmidt