[PATCH net 1/2] net/rtnetlink: add IFLA_GSO_MAX_SEGS and IFLA_GSO_MAX_SIZE attributes

[Eric Dumazet <edumazet@google.com>]

It can be useful to report dev->gso_max_segs and dev->gso_max_size
so that "ip -d link" can display them to help debugging.

For the moment, these attributes are read-only.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Petri Gynther <pgynther@google.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
---
 include/uapi/linux/if_link.h | 2 ++
 net/core/rtnetlink.c         | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 8e3f88fa5b59..76d315ca597d 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -153,6 +153,8 @@ enum {
 	IFLA_LINK_NETNSID,
 	IFLA_PHYS_PORT_NAME,
 	IFLA_PROTO_DOWN,
+	IFLA_GSO_MAX_SEGS,
+	IFLA_GSO_MAX_SIZE,
 	__IFLA_MAX
 };
 
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index d2d9e5ebf58e..a69cd0c097b5 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -895,6 +895,8 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
 	       + nla_total_size(4) /* IFLA_PROMISCUITY */
 	       + nla_total_size(4) /* IFLA_NUM_TX_QUEUES */
 	       + nla_total_size(4) /* IFLA_NUM_RX_QUEUES */
+	       + nla_total_size(4) /* IFLA_MAX_GSO_SEGS */
+	       + nla_total_size(4) /* IFLA_MAX_GSO_SIZE */
 	       + nla_total_size(1) /* IFLA_OPERSTATE */
 	       + nla_total_size(1) /* IFLA_LINKMODE */
 	       + nla_total_size(4) /* IFLA_CARRIER_CHANGES */
@@ -1223,6 +1225,8 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 	    nla_put_u32(skb, IFLA_GROUP, dev->group) ||
 	    nla_put_u32(skb, IFLA_PROMISCUITY, dev->promiscuity) ||
 	    nla_put_u32(skb, IFLA_NUM_TX_QUEUES, dev->num_tx_queues) ||
+	    nla_put_u32(skb, IFLA_GSO_MAX_SEGS, dev->gso_max_segs) ||
+	    nla_put_u32(skb, IFLA_GSO_MAX_SIZE, dev->gso_max_size) ||
 #ifdef CONFIG_RPS
 	    nla_put_u32(skb, IFLA_NUM_RX_QUEUES, dev->num_rx_queues) ||
 #endif
-- 
2.8.0.rc3.226.g39d4020