Hi Alex,
On Wed, Feb 15, 2017 at 9:44 AM, Alexander Aring <aar@xxxxxxxxxxxxxx> wrote:
>
> Hi,
>
> On 02/09/2017 03:55 PM, Luiz Augusto von Dentz wrote:
>> From: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
>>
>> This allow technologies such as Bluetooth to use its native lladdr which
>> is eui48 instead of eui64 which was expected by functions like
>> lowpan_header_decompress and lowpan_header_compress.
>>
>> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
>> ---
>> net/6lowpan/iphc.c | 17 +++++++++++++++--
>> net/bluetooth/6lowpan.c | 43 ++++++++++---------------------------------
>> 2 files changed, 25 insertions(+), 35 deletions(-)
>>
>> diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
>> index fb5f6fa..ee88feb 100644
>> --- a/net/6lowpan/iphc.c
>> +++ b/net/6lowpan/iphc.c
>> @@ -827,8 +827,21 @@ static u8 lowpan_compress_ctx_addr(u8 **hc_ptr, const struct net_device *dev,
>> }
>> break;
>> default:
>> - /* check for SAM/DAM = 11 */
>> - memcpy(&tmp.s6_addr[8], lladdr, EUI64_ADDR_LEN);
>> + switch (dev->addr_len) {
>> + case ETH_ALEN:
>> + memcpy(&tmp.s6_addr[8], lladdr, 3);
>> + tmp.s6_addr[11] = 0xFF;
>> + tmp.s6_addr[12] = 0xFE;
>> + memcpy(&tmp.s6_addr[13], lladdr + 3, 3);
>> + break;
>> + case EUI64_ADDR_LEN:
>> + memcpy(&tmp.s6_addr[8], lladdr, EUI64_ADDR_LEN);
>> + break;
>> + default:
>> + dam = LOWPAN_IPHC_DAM_11;
>> + goto out;
>> + }
>> +
>> /* second bit-flip (Universe/Local) is done according RFC2464 */
>> tmp.s6_addr[8] ^= 0x02;
>
> move this handling in per link-layer layer decision, see below.
>
>> /* context information are always used */
>
> PLEASE... and this is one of my rant!
>
> PLEASE LOOK WHAT I HAVE DONE IN THIS FILE IN MY RFC PATCH SERIES YOU
> NEED TO FIX MORE THAN JUST CONTEXT BASED COMPRESSION.
>
> e.g. stateless un/compression
I haven't changed that and probably it needs a separate patch in that
case since Im only, and I really mean only, fixing the address length
and because your patches end up changing a lot more things it is
pretty hard to extract the exact parts that fixes this.
> Now I for this, I want to see a link-layer evaluation not address length based.
> Please do so also for the other patch which fixing some behaviour in ipv6.
> The reason is here that uncompress/compress addresses are defined by RFC
> 6LoWPAN adapation.
>
> There is already a link-layer case, so please add BTLE LLTYPE there! Not
> move your handling in default, add some WARN_ONCE there...
Here I have to pretty blunt, it is a mistake to put link layer logic
inside the 6lowpan module, first it creates a dependencies of these
technologies and second it slow down the development because we end up
with multiple trees having to synchronize which each other.
Also I have not seen a single mention of link local IP that is not
using 6 or 8 bytes link layer format, and in fact if there exist one
then we should probably have the caller handle the link local ip
format, but then again I haven't seen any indication that these needs
changing in fact for 15.4 16 bit address you can generate a valid 8
bytes address before calling 6lowpan API, which is probably what we
should do to avoid depending on 15.4 code inside 6lowpan.
> btw:
>
> here exists also a cleanup to not always implement the same stuff. We
> need for stateful/stateless compression one function, because and
> remember my words if you want to make this cleanup:
>
> Stateless compression is stateful compression with prefix fe80::/64 as
> context.
>
> ---
>
> Sorry for my rant, but I am somehow pissed off because intel people
> doesn't look what I did there in my RFC.
>
> ... I think now I know why linux kernel people do sometimes a rant. :-)
>
> Thanks.
>
>> diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
>> index 1456b01..d2a1aa5 100644
>> --- a/net/bluetooth/6lowpan.c
>> +++ b/net/bluetooth/6lowpan.c
>> @@ -64,7 +64,7 @@ struct lowpan_peer {
>> struct l2cap_chan *chan;
>>
>> /* peer addresses in various formats */
>> - unsigned char eui64_addr[EUI64_ADDR_LEN];
>> + unsigned char lladdr[ETH_ALEN];
>> struct in6_addr peer_addr;
>> };
>>
>> @@ -80,8 +80,6 @@ struct lowpan_btle_dev {
>> struct delayed_work notify_peers;
>> };
>>
>> -static void set_addr(u8 *eui, u8 *addr, u8 addr_type);
>> -
>> static inline struct lowpan_btle_dev *
>> lowpan_btle_dev(const struct net_device *netdev)
>> {
>> @@ -277,7 +275,6 @@ static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
>> const u8 *saddr;
>> struct lowpan_btle_dev *dev;
>> struct lowpan_peer *peer;
>> - unsigned char eui64_daddr[EUI64_ADDR_LEN];
>>
>> dev = lowpan_btle_dev(netdev);
>>
>> @@ -287,10 +284,9 @@ static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
>> if (!peer)
>> return -EINVAL;
>>
>> - saddr = peer->eui64_addr;
>> - set_addr(&eui64_daddr[0], chan->src.b, chan->src_type);
>> + saddr = peer->lladdr;
>>
>> - return lowpan_header_decompress(skb, netdev, &eui64_daddr, saddr);
>> + return lowpan_header_decompress(skb, netdev, netdev->dev_addr, saddr);
>
> This looks not right, you are sure that netdev->dev_addr is the
> _destination_ address? It looks very confusing, because dev_addr is
> normally the source address of the netdevice interface.
>
>> }
>>
>> static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
>> @@ -477,7 +473,7 @@ static int setup_header(struct sk_buff *skb, struct net_device *netdev,
>> }
>> }
>>
>> - daddr = peer->eui64_addr;
>> + daddr = peer->lladdr;
>> *peer_addr = addr;
>> *peer_addr_type = addr_type;
>> lowpan_cb(skb)->chan = peer->chan;
>> @@ -663,27 +659,6 @@ static struct device_type bt_type = {
>> .name = "bluetooth",
>> };
>>
>> -static void set_addr(u8 *eui, u8 *addr, u8 addr_type)
>> -{
>> - /* addr is the BT address in little-endian format */
>> - eui[0] = addr[5];
>> - eui[1] = addr[4];
>> - eui[2] = addr[3];
>> - eui[3] = 0xFF;
>> - eui[4] = 0xFE;
>> - eui[5] = addr[2];
>> - eui[6] = addr[1];
>> - eui[7] = addr[0];
>> -
>> - /* Universal/local bit set, BT 6lowpan draft ch. 3.2.1 */
>> - if (addr_type == BDADDR_LE_PUBLIC)
>> - eui[0] &= ~0x02;
>> - else
>> - eui[0] |= 0x02;
>> -
>> - BT_DBG("type %d addr %*phC", addr_type, 8, eui);
>> -}
>> -
>
> YAY, this function is totally wrong! :-)
>
>> static void ifup(struct net_device *netdev)
>> {
>> int err;
>> @@ -762,14 +737,16 @@ static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
>> peer->chan = chan;
>> memset(&peer->peer_addr, 0, sizeof(struct in6_addr));
>>
>> + baswap((void *)peer->lladdr, &chan->dst);
>> +
>> /* RFC 2464 ch. 5 */
>> peer->peer_addr.s6_addr[0] = 0xFE;
>> peer->peer_addr.s6_addr[1] = 0x80;
>> - set_addr((u8 *)&peer->peer_addr.s6_addr + 8, chan->dst.b,
>> - chan->dst_type);
>>
>> - memcpy(&peer->eui64_addr, (u8 *)&peer->peer_addr.s6_addr + 8,
>> - EUI64_ADDR_LEN);
>> + memcpy(&peer->peer_addr.s6_addr[8], peer->lladdr, 3);
>> + peer->peer_addr.s6_addr[11] = 0xFF;
>> + peer->peer_addr.s6_addr[12] = 0xFE;
>> + memcpy(&peer->peer_addr.s6_addr[13], peer->lladdr + 3, 3);
>>
>
> What the hell is that? I suppose this is to handling something correct
> to a behaviour which is another big thing which is totally broken in the
> BTLE 6LoWPAN code.
>
>> /* IPv6 address needs to have the U/L bit set properly so toggle
>> * it back here.
>>
>
> - Alex
--
Luiz Augusto von Dentz
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