netdev - Re: [PATCH net 3/7] net: ip6_gre: Split up ip6gre_tnl_link

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Message-ID: <CALDO+SaaCHf2YR+6NWoOb7k3JCeLE7Wi3E3wqTOQu=YOmP=rKQ@mail.gmail.com>
Date:   Thu, 17 May 2018 12:45:11 -0700
From:   William Tu <u9012063@...il.com>
To:     Petr Machata <petrm@...lanox.com>
Cc:     Linux Kernel Network Developers <netdev@...r.kernel.org>,
        David Miller <davem@...emloft.net>,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        Dmitry Kozlov <xeb@...l.ru>
Subject: Re: [PATCH net 3/7] net: ip6_gre: Split up ip6gre_tnl_link_config()

On Thu, May 17, 2018 at 7:36 AM, Petr Machata <petrm@...lanox.com> wrote:
> The function ip6gre_tnl_link_config() is used for setting up
> configuration of both ip6gretap and ip6erspan tunnels. Split the
> function into the common part and the route-lookup part. The latter then
> takes the calculated header length as an argument. This split will allow
> the patches down the line to sneak in a custom header length computation
> for the ERSPAN tunnel.
>
> Signed-off-by: Petr Machata <petrm@...lanox.com>
> ---

LGTM.
Acked-by: William Tu <u9012063@...il.com>

>  net/ipv6/ip6_gre.c | 38 ++++++++++++++++++++++++++------------
>  1 file changed, 26 insertions(+), 12 deletions(-)
>
> diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
> index 53b1531..78ba6b9 100644
> --- a/net/ipv6/ip6_gre.c
> +++ b/net/ipv6/ip6_gre.c
> @@ -1022,12 +1022,11 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
>         return NETDEV_TX_OK;
>  }
>
> -static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu)
> +static void ip6gre_tnl_link_config_common(struct ip6_tnl *t)
>  {
>         struct net_device *dev = t->dev;
>         struct __ip6_tnl_parm *p = &t->parms;
>         struct flowi6 *fl6 = &t->fl.u.ip6;
> -       int t_hlen;
>
>         if (dev->type != ARPHRD_ETHER) {
>                 memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
> @@ -1054,12 +1053,13 @@ static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu)
>                 dev->flags |= IFF_POINTOPOINT;
>         else
>                 dev->flags &= ~IFF_POINTOPOINT;
> +}
>
> -       t->tun_hlen = gre_calc_hlen(t->parms.o_flags);
> -
> -       t->hlen = t->encap_hlen + t->tun_hlen;
> -
> -       t_hlen = t->hlen + sizeof(struct ipv6hdr);
> +static void ip6gre_tnl_link_config_route(struct ip6_tnl *t, int set_mtu,
> +                                        int t_hlen)
> +{
> +       const struct __ip6_tnl_parm *p = &t->parms;
> +       struct net_device *dev = t->dev;
>
>         if (p->flags & IP6_TNL_F_CAP_XMIT) {
>                 int strict = (ipv6_addr_type(&p->raddr) &
> @@ -1091,6 +1091,24 @@ static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu)
>         }
>  }
>
> +static int ip6gre_calc_hlen(struct ip6_tnl *tunnel)
> +{
> +       int t_hlen;
> +
> +       tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
> +       tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
> +
> +       t_hlen = tunnel->hlen + sizeof(struct ipv6hdr);
> +       tunnel->dev->hard_header_len = LL_MAX_HEADER + t_hlen;
> +       return t_hlen;
> +}
> +
> +static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu)
> +{
> +       ip6gre_tnl_link_config_common(t);
> +       ip6gre_tnl_link_config_route(t, set_mtu, ip6gre_calc_hlen(t));
> +}
> +
>  static int ip6gre_tnl_change(struct ip6_tnl *t,
>         const struct __ip6_tnl_parm *p, int set_mtu)
>  {
> @@ -1384,11 +1402,7 @@ static int ip6gre_tunnel_init_common(struct net_device *dev)
>                 return ret;
>         }
>
> -       tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
> -       tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
> -       t_hlen = tunnel->hlen + sizeof(struct ipv6hdr);
> -
> -       dev->hard_header_len = LL_MAX_HEADER + t_hlen;
> +       t_hlen = ip6gre_calc_hlen(tunnel);
>         dev->mtu = ETH_DATA_LEN - t_hlen;
>         if (dev->type == ARPHRD_ETHER)
>                 dev->mtu -= ETH_HLEN;
> --
> 2.4.11
>