netdev - Re: [PATCH v6] ipvs: allow tunneling with gue encapsulation

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Date:   Tue, 26 Mar 2019 09:46:07 +0200 (EET)
From:   Julian Anastasov <ja@....bg>
To:     Jacky Hu <hengqing.hu@...il.com>
cc:     jacky.hu@...mart.com, jason.niesz@...mart.com,
        "David S. Miller" <davem@...emloft.net>,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        Wensong Zhang <wensong@...ux-vs.org>,
        Simon Horman <horms@...ge.net.au>,
        Pablo Neira Ayuso <pablo@...filter.org>,
        Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu>,
        Florian Westphal <fw@...len.de>, netdev@...r.kernel.org,
        lvs-devel@...r.kernel.org, linux-kernel@...r.kernel.org,
        netfilter-devel@...r.kernel.org, coreteam@...filter.org
Subject: Re: [PATCH v6] ipvs: allow tunneling with gue encapsulation


	Hello,

On Tue, 26 Mar 2019, Jacky Hu wrote:

> ipip packets are blocked in some public cloud environments, this patch
> allows gue encapsulation with the tunneling method, which would make
> tunneling working in those environments.
> 
> Signed-off-by: Jacky Hu <hengqing.hu@...il.com>
> ---
>  include/net/ip_vs.h             |  5 ++
>  include/uapi/linux/ip_vs.h      | 11 +++++
>  net/netfilter/ipvs/ip_vs_ctl.c  | 35 +++++++++++++-
>  net/netfilter/ipvs/ip_vs_xmit.c | 86 +++++++++++++++++++++++++++++++--
>  4 files changed, 132 insertions(+), 5 deletions(-)
> 

> diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
> index 473cce2a5231..36819c2fabf1 100644
> --- a/net/netfilter/ipvs/ip_vs_xmit.c
> +++ b/net/netfilter/ipvs/ip_vs_xmit.c

> @@ -1054,11 +1104,21 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
>  	if (IS_ERR(skb))
>  		goto tx_error;
>  
> -	if (iptunnel_handle_offloads(skb, __tun_gso_type_mask(AF_INET, cp->af)))
> +	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
> +		gso_type = SKB_GSO_UDP_TUNNEL;
> +	else
> +		gso_type = __tun_gso_type_mask(AF_INET, cp->af);

	Looks like we should request the IP segmentation. Looking
at skb_udp_tunnel_segment() we call the proper gso_inner_segment
handler but ipip_gso_segment() still requires its bit in gso_type.
So, in both functions we should do:

	gso_type = __tun_gso_type_mask();
	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
		gso_type |= SKB_GSO_UDP_TUNNEL;

	Probably, it can be tested with local client sending large
TCP packets...

> @@ -1134,17 +1197,32 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
>  	 */
>  	max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct ipv6hdr);
>  
> +	tun_type = cp->dest->tun_type;
> +
> +	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
> +		max_headroom += sizeof(struct udphdr) + sizeof(struct guehdr);
> +
>  	skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
>  					 &next_protocol, &payload_len,
>  					 &dsfield, &ttl, NULL);
>  	if (IS_ERR(skb))
>  		goto tx_error;
>  
> -	if (iptunnel_handle_offloads(skb, __tun_gso_type_mask(AF_INET6, cp->af)))
> +	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
> +		gso_type = SKB_GSO_UDP_TUNNEL;
> +	else
> +		gso_type = __tun_gso_type_mask(AF_INET6, cp->af);

	Here too

> +	if (iptunnel_handle_offloads(skb, gso_type))
>  		goto tx_error;

Regards

--
Julian Anastasov <ja@....bg>