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

From: Julian Anastasov
Date: Tue Mar 26 2019 - 03:47:26 EST



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@xxxxxxxxx>
> ---
> 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@xxxxxx>