netdev - RE: [PATCH v2 net] be2net: Allow GRE to work concurrently while a VxLAN tunnel is configured

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <31318D46B5DF3F4AB71CC057601E9FEB3A7F5178@CMEXMB1.ad.emulex.com>
Date:	Thu, 15 Jan 2015 04:59:30 +0000
From:	Sriharsha Basavapatna <Sriharsha.Basavapatna@...lex.Com>
To:	Tom Herbert <therbert@...gle.com>
CC:	Linux Netdev List <netdev@...r.kernel.org>
Subject: RE: [PATCH v2 net] be2net: Allow GRE to work concurrently while a
 VxLAN tunnel is configured



-----Original Message-----
From: Tom Herbert [mailto:therbert@...gle.com] 
Sent: Thursday, January 15, 2015 8:00 AM
To: Sriharsha Basavapatna
Cc: Linux Netdev List
Subject: Re: [PATCH v2 net] be2net: Allow GRE to work concurrently while a VxLAN tunnel is configured

On Thu, Jan 15, 2015 at 2:38 AM, Sriharsha Basavapatna <sriharsha.basavapatna@...lex.com> wrote:
> Other tunnels like GRE break while VxLAN offloads are enabled in 
> Skyhawk-R. To avoid this, we should restrict offload features on a 
> per-packet basis in such conditions.
>
> Signed-off-by: Sriharsha Basavapatna 
> <sriharsha.basavapatna@...lex.com>
> ---
> v2 changes: fixed minor nits pointed out by Sergei Shtylyov
> ---
>  drivers/net/ethernet/emulex/benet/be_main.c |   41 +++++++++++++++++++++++++--
>  1 file changed, 38 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/emulex/benet/be_main.c 
> b/drivers/net/ethernet/emulex/benet/be_main.c
> index 41a0a54..d48806b 100644
> --- a/drivers/net/ethernet/emulex/benet/be_main.c
> +++ b/drivers/net/ethernet/emulex/benet/be_main.c
> @@ -4383,8 +4383,9 @@ static int be_ndo_bridge_getlink(struct sk_buff *skb, u32 pid, u32 seq,
>   * distinguish various types of transports (VxLAN, GRE, NVGRE ..). So, offload
>   * is expected to work across all types of IP tunnels once exported. Skyhawk
>   * supports offloads for either VxLAN or NVGRE, exclusively. So we 
> export VxLAN
> - * offloads in hw_enc_features only when a VxLAN port is added. Note 
> this only
> - * ensures that other tunnels work fine while VxLAN offloads are not enabled.
> + * offloads in hw_enc_features only when a VxLAN port is added. If 
> + other (non
> + * VxLAN) tunnels are configured while VxLAN offloads are enabled, 
> + offloads for
> + * those other tunnels are unexported on the fly through ndo_features_check().
>   *
>   * Skyhawk supports VxLAN offloads only for one UDP dport. So, if the stack
>   * adds more than one port, disable offloads and don't re-enable them 
> again @@ -4463,7 +4464,41 @@ static netdev_features_t be_features_check(struct sk_buff *skb,
>                                            struct net_device *dev,
>                                            netdev_features_t features)  
> {
> -       return vxlan_features_check(skb, features);
> +       struct be_adapter *adapter = netdev_priv(dev);
> +       u8 l4_hdr = 0;
> +
> +       /* The code below restricts offload features for some tunneled packets.
> +        * Offload features for normal (non tunnel) packets are unchanged.
> +        */
> +       if (!skb->encapsulation ||
> +           !(adapter->flags & BE_FLAGS_VXLAN_OFFLOADS))
> +               return features;
> +
> +       /* It's an encapsulated packet and VxLAN offloads are enabled. We
> +        * should disable tunnel offload features if it's not a VxLAN packet,
> +        * as tunnel offloads have been enabled only for VxLAN. This is done to
> +        * allow other tunneled traffic like GRE work fine while VxLAN
> +        * offloads are configured in Skyhawk-R.
> +        */
> +       switch (vlan_get_protocol(skb)) {
> +       case htons(ETH_P_IP):
> +               l4_hdr = ip_hdr(skb)->protocol;
> +               break;
> +       case htons(ETH_P_IPV6):
> +               l4_hdr = ipv6_hdr(skb)->nexthdr;
> +               break;
> +       default:
> +               return features;
> +       }
> +
> +       if (l4_hdr != IPPROTO_UDP ||

I don't understand why this is needed. The only GSO type with with encapsulation allowed by device features SKB_GSO_UDP_TUNNEL. This should not be GRE for instance. Do you see cases where protocol is not UDP at this point?
[Harsha] It's needed for GRE checksum case; without this,  GRE pkts are sent down without checksum by the stack, but HW
can only offload checksum for VxLAN pkts.

> +           skb->inner_protocol_type != ENCAP_TYPE_ETHER ||
> +           skb->inner_protocol != htons(ETH_P_TEB) ||
> +           skb_inner_mac_header(skb) - skb_transport_header(skb) !=
> +           sizeof(struct udphdr) + sizeof(struct vxlanhdr))
> +               return features & ~(NETIF_F_ALL_CSUM | 
> + NETIF_F_GSO_MASK);
> +
> +       return features;
>  }
>  #endif
>
> --
> 1.7.9.5
>
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in 
> the body of a message to majordomo@...r.kernel.org More majordomo info 
> at  http://vger.kernel.org/majordomo-info.html