[PATCH RFC 2/3] net: Support IFLA_ENV_HDR_LEN to configure max envelope header length

[Toshiaki Makita]

With this change, admin can configure env_hdr_len.

Signed-off-by: Toshiaki Makita <makita.toshi...@lab.ntt.co.jp>
---
 include/uapi/linux/if_link.h |  1 +
 net/core/rtnetlink.c         | 16 ++++++++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index b4fba66..9545ea4 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -157,6 +157,7 @@ enum {
        IFLA_GSO_MAX_SIZE,
        IFLA_PAD,
        IFLA_XDP,
+       IFLA_ENV_HDR_LEN,
        __IFLA_MAX
 };
 
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 3ac8946..9233709 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -943,7 +943,8 @@ static noinline size_t if_nlmsg_size(const struct 
net_device *dev,
               + nla_total_size(MAX_PHYS_ITEM_ID_LEN) /* IFLA_PHYS_SWITCH_ID */
               + nla_total_size(IFNAMSIZ) /* IFLA_PHYS_PORT_NAME */
               + rtnl_xdp_size(dev) /* IFLA_XDP */
-              + nla_total_size(1); /* IFLA_PROTO_DOWN */
+              + nla_total_size(1) /* IFLA_PROTO_DOWN */
+              + nla_total_size(4); /* IFLA_ENV_HDR_LEN */
 
 }
 
@@ -1321,7 +1322,8 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct 
net_device *dev,
             nla_put_string(skb, IFLA_IFALIAS, dev->ifalias)) ||
            nla_put_u32(skb, IFLA_CARRIER_CHANGES,
                        atomic_read(&dev->carrier_changes)) ||
-           nla_put_u8(skb, IFLA_PROTO_DOWN, dev->proto_down))
+           nla_put_u8(skb, IFLA_PROTO_DOWN, dev->proto_down) ||
+           nla_put_u32(skb, IFLA_ENV_HDR_LEN, netif_get_env_hdr_len(dev)))
                goto nla_put_failure;
 
        if (rtnl_fill_link_ifmap(skb, dev))
@@ -1458,6 +1460,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
        [IFLA_LINK_NETNSID]     = { .type = NLA_S32 },
        [IFLA_PROTO_DOWN]       = { .type = NLA_U8 },
        [IFLA_XDP]              = { .type = NLA_NESTED },
+       [IFLA_ENV_HDR_LEN]      = { .type = NLA_U32 },
 };
 
 static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
@@ -2174,6 +2177,13 @@ static int do_setlink(const struct sk_buff *skb,
                }
        }
 
+       if (tb[IFLA_ENV_HDR_LEN]) {
+               err = dev_set_env_hdr_len(dev, 
nla_get_u32(tb[IFLA_ENV_HDR_LEN]));
+               if (err < 0)
+                       goto errout;
+               status |= DO_SETLINK_MODIFIED;
+       }
+
 errout:
        if (status & DO_SETLINK_MODIFIED) {
                if (status & DO_SETLINK_NOTIFY)
@@ -2378,6 +2388,8 @@ struct net_device *rtnl_create_link(struct net *net,
                dev->link_mode = nla_get_u8(tb[IFLA_LINKMODE]);
        if (tb[IFLA_GROUP])
                dev_set_group(dev, nla_get_u32(tb[IFLA_GROUP]));
+       if (tb[IFLA_ENV_HDR_LEN])
+               dev->env_hdr_len = nla_get_u32(tb[IFLA_ENV_HDR_LEN]);
 
        return dev;
 
-- 
1.8.3.1