[PATCH 1/2] rtnetlink: allow GSO maximums to be passed to device

[Solio Sarabia]

From: Stephen Hemminger <step...@networkplumber.org>

Allow GSO maximum segments and size as netlink parameters on input,
with 'ip link add' utils for example. Allow also updating these
attributes after rtnetlink devices are created.

Signed-off-by: Stephen Hemminger <sthem...@microsoft.com>
Signed-off-by: Solio Sarabia <solio.sara...@intel.com>
---
 net/core/rtnetlink.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index a4faefd..a1ff2a8 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1637,6 +1637,8 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
        [IFLA_PROMISCUITY]      = { .type = NLA_U32 },
        [IFLA_NUM_TX_QUEUES]    = { .type = NLA_U32 },
        [IFLA_NUM_RX_QUEUES]    = { .type = NLA_U32 },
+       [IFLA_GSO_MAX_SEGS]     = { .type = NLA_U32 },
+       [IFLA_GSO_MAX_SIZE]     = { .type = NLA_U32 },
        [IFLA_PHYS_PORT_ID]     = { .type = NLA_BINARY, .len = 
MAX_PHYS_ITEM_ID_LEN },
        [IFLA_CARRIER_CHANGES]  = { .type = NLA_U32 },  /* ignored */
        [IFLA_PHYS_SWITCH_ID]   = { .type = NLA_BINARY, .len = 
MAX_PHYS_ITEM_ID_LEN },
@@ -2287,6 +2289,34 @@ static int do_setlink(const struct sk_buff *skb,
                }
        }
 
+       if (tb[IFLA_GSO_MAX_SIZE]) {
+               u32 max_size = nla_get_u32(tb[IFLA_GSO_MAX_SIZE]);
+
+               if (max_size > GSO_MAX_SIZE) {
+                       err = -EINVAL;
+                       goto errout;
+               }
+
+               if (dev->gso_max_size ^ max_size) {
+                       netif_set_gso_max_size(dev, max_size);
+                       status |= DO_SETLINK_MODIFIED;
+               }
+       }
+
+       if (tb[IFLA_GSO_MAX_SEGS]) {
+               u32 max_segs = nla_get_u32(tb[IFLA_GSO_MAX_SEGS]);
+
+               if (max_segs > GSO_MAX_SEGS) {
+                       err = -EINVAL;
+                       goto errout;
+               }
+
+               if (dev->gso_max_segs ^ max_segs) {
+                       dev->gso_max_segs = max_segs;
+                       status |= DO_SETLINK_MODIFIED;
+               }
+       }
+
        if (tb[IFLA_OPERSTATE])
                set_operstate(dev, nla_get_u8(tb[IFLA_OPERSTATE]));
 
-- 
2.7.4