[ovs-discuss] query related to GRE encapsulation

[Chetan Bali]

Hi Ben,

Checked out the function format_odp_key_attr(), it has the correct parameters in form of struct ds->string. This string shows correct set of tunnelling params. But we need to do parsing in dpif class. Can you suggest how can we do this? Looks like we aren't doing the correct netlink parsing as mentioned in below code snippet.

Thanks
Chetan Bali

-----Original Message-----
From: Ben Pfaff [mailto:blp at nicira.com]
Sent: 24 February 2015 23:57
To: Chetan Bali
Cc: dev at openvswitch.org; discuss at openvswitch.org; Mohit Malik
Subject: Re: [ovs-discuss] query related to GRE encapsulation

Have you looked at the code in odp-util.c that prints these structures, e.g. format_odp_key_attr()?

On Tue, Feb 24, 2015 at 05:00:31PM +0000, Chetan Bali wrote:
> Hi Ben,
>
> Thanks for the quick response. Please find the code snippet below:
>
> This below function is called from flow_put in dpif class code.
>
> uint8_t dpif_tunnel_parse_actions(s_action_t *action_list, const
> struct nlattr *actions, size_t actions_len, struct flow_tnl
> *tun_param) { if(OVS_LIKELY(NULL != actions))
>     {
>         NL_ATTR_FOR_EACH_UNSAFE(a, len, actions, actions_len)
>         {
>             switch (nl_attr_type(a))
>             {
>                 case OVS_ACTION_ATTR_SET:
>                     VLOG_INFO("Action type is ACTION_SET \n");
>                         action_list[num_action].action_type = ACTION_SET_IPV4_TUNNEL;
>                     if (nla_type(nla_data(a)) == OVS_KEY_ATTR_TUNNEL)
>                     {
>                         tun_param = nla_data(nla_data(a));
>                         VLOG_INFO(" OVS_ACTION_ATTR_TUNNEL TUN_ID : %u\n",tun_param->tun_id);
>                         VLOG_INFO(" OVS_ACTION_ATTR_TUNNEL SRC_ADRR : %x\n",ntohl(tun_param->ipv4_src));
>                         VLOG_INFO(" OVS_ACTION_ATTR_TUNNEL SRC_DST : %x\n",ntohl(tun_param->ipv4_dst));
>                         VLOG_INFO(" OVS_ACTION_ATTR_TUNNEL TUN_FLAG : %u\n",tun_param->tun_flags);
>                         VLOG_INFO(" OVS_ACTION_ATTR_TUNNEL TOS : %u\n",tun_param->ipv4_tos);
>                         VLOG_INFO(" OVS_ACTION_ATTR_TUNNEL TTL : %u\n",tun_param->ipv4_ttl);
>                     }
>
> We are not getting correct values of tun_id, tun_src, tun_dst, tun_ttl, etc.
>
> It will be great if you could help us here.
>
> Thanks
> Chetan Bali
>
> -----Original Message-----
> From: Ben Pfaff [mailto:blp at nicira.com]
> Sent: 24 February 2015 22:15
> To: Chetan Bali
> Cc: dev at openvswitch.org; discuss at openvswitch.org; Mohit Malik
> Subject: Re: [ovs-discuss] query related to GRE encapsulation
>
> On Tue, Feb 24, 2015 at 01:33:29PM +0000, Chetan Bali wrote:
> > I am configuring gre-port in my ovs bridge, for establishing
> > gre-tunnel between 2 machines. I am trying to parse the tunnelling key params sent by OVS while adding flow, when it sets action as OVS_ACTION_ATTR_SET. I am parsing the tun-key attributes in dpif-linux.c in exact manner as ovs does, i.e., nla_data(nla_data(action)) where action is in "nlattr"  type. Tun-key params that I am trying to fetch are as per struct "ovs_key_ipv4_tunnel" i.e., struct ovs_key_ipv4_tunnel {
> >     __be64 tun_id;
> >     __be32 ipv4_src;
> >     __be32 ipv4_dst;
> >     __be16 tun_flags;
> >     u8   ipv4_tos;
> >     u8   ipv4_ttl;
> > };
> > The problem is that, while parsing I am getting incorrect tun-key params, whereas I can see by putting prints that openvswitchd.ko is getting correct tun-key params.
>
> I guess you're doing something wrong.  Show us your code?
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