Re: ICMPv6 Redirects

[Simon Vincent <simon.vincent@xsilon.com>]

I can confirm that this fixes the problem. I will create some patches 
when I get a chance.
Thanks

Simon

On 29/09/14 17:41, Alexander Aring wrote:
> Hi Simon,
>
> On Mon, Sep 29, 2014 at 03:12:21PM +0100, Simon Vincent wrote:
>> On 29/09/14 14:58, Alexander Aring wrote:
>>> On Mon, Sep 29, 2014 at 02:51:51PM +0100, Simon Vincent wrote:
>>>> Sorry for the confusion. My problem is I am receiving all packets.
>>>> PACKET_OTHERHOST does not seem to be dropped. A suggestion from Varka was to
>>>> disable redirects however it now seems that this is not possible on a ipv6
>>>> interface.
>>>>
>>>> I can fix the problem by dropping PACKET_OTHERHOST in mac802154_subif_frame.
>>> The first what IPv6 does is [0].
>>>
>>> See my previous mail. Also that we should handle on 6LoWPAN packet
>>> handler function for receiving "lowpan_rcv" we should do the same,
>>> otherwise we parsing PACKET_OTHERHOST sk_buff's and drop these directly
>>> in IPv6 layer, which makes no sense.
>>>
>>> But what I see is that the current behaviour should also work.
>>> Instrument the IPv6 delivery function and be sure that the information
>>> about PACKET_OTHERHOST was not dropped.
>> I do not catch any PACKET_OTHERHOST packets in the ip6_input.c ipv6_rcv
>> function.
>> I don't think the packets get this far. Also in the ieee802154_rcv function
>> they are dropped. I will add some more debug to find where the redirects
>> come from.
> please try this:
>
>
> diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
> index 142eef5..002cd7c 100644
> --- a/net/6lowpan/iphc.c
> +++ b/net/6lowpan/iphc.c
> @@ -189,7 +189,6 @@ static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
>          skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
>   
>          new->protocol = htons(ETH_P_IPV6);
> -       new->pkt_type = PACKET_HOST;
>          new->dev = dev;
>   
>          raw_dump_table(__func__, "raw skb data dump before receiving",
> diff --git a/net/ieee802154/6lowpan_rtnl.c b/net/ieee802154/6lowpan_rtnl.c
> index 4413629..820922a 100644
> --- a/net/ieee802154/6lowpan_rtnl.c
> +++ b/net/ieee802154/6lowpan_rtnl.c
> @@ -515,6 +515,9 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
>          if (!netif_running(dev))
>                  goto drop_skb;
>   
> +       if (skb->pkt_type == PACKET_OTHERHOST)
> +               goto drop_skb;
> +
>          if (dev->type != ARPHRD_IEEE802154)
>                  goto drop_skb;
>   
> @@ -524,7 +527,6 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
>          /* check that it's our buffer */
>          if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
>                  skb->protocol = htons(ETH_P_IPV6);
> -               skb->pkt_type = PACKET_HOST;
>   
>                  /* Pull off the 1-byte of 6lowpan header. */
>                  skb_pull(skb, 1);
>
>
>
> should fix the issue, somebody overwrite the pkt_type skb attribute always
> with PACKET_HOST, which is wrong.
>
> Also we can first check this in lowpan_rcv and drop the skb when it's
> not belong to us.
>
> If you want to fix this mainline please seperate it in 3 patches, one
> for generic 6lowpan, other ieee802154 6lowpan and one for the check on
> PACKET_OTHERHOST in lowpan_rcv.
>
> - Alex