[NET] core: add RFC2863 operstate

this patch adds a dormant flag to network devices, RFC2863 operstate derived
from these flags and possibility for userspace interaction. It allows drivers
to signal that a device is unusable for user traffic without disabling
queueing (and therefore the possibility for protocol establishment traffic to
flow) and a userspace supplicant (WPA, 802.1X) to mark a device unusable
without changes to the driver.

It is the result of our long discussion. However I must admit that it
represents what Jamal and I agreed on with compromises towards Krzysztof, but
Thomas and Krzysztof still disagree with some parts. Anyway I think it should
be applied.

Signed-off-by: Stefan Rompf <stefan@loplof.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 50 insertions, 0 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index eca2976abb25..1c15a907066f 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -179,6 +179,33 @@ rtattr_failure:
 }
 
 
+static void set_operstate(struct net_device *dev, unsigned char transition)
+{
+        unsigned char operstate = dev->operstate;
+
+        switch(transition) {
+        case IF_OPER_UP:
+                if ((operstate == IF_OPER_DORMANT ||
+                     operstate == IF_OPER_UNKNOWN) &&
+                    !netif_dormant(dev))
+                        operstate = IF_OPER_UP;
+                break;
+
+        case IF_OPER_DORMANT:
+                if (operstate == IF_OPER_UP ||
+                    operstate == IF_OPER_UNKNOWN)
+                        operstate = IF_OPER_DORMANT;
+                break;
+        };
+
+        if (dev->operstate != operstate) {
+                write_lock_bh(&dev_base_lock);
+                dev->operstate = operstate;
+                write_unlock_bh(&dev_base_lock);
+                netdev_state_change(dev);
+        }
+}
+
 static int rtnetlink_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
                                  int type, u32 pid, u32 seq, u32 change, 
                                  unsigned int flags)
@@ -209,6 +236,13 @@ static int rtnetlink_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
         }
 
         if (1) {
+                u8 operstate = netif_running(dev)?dev->operstate:IF_OPER_DOWN;
+                u8 link_mode = dev->link_mode;
+                RTA_PUT(skb, IFLA_OPERSTATE, sizeof(operstate), &operstate);
+                RTA_PUT(skb, IFLA_LINKMODE, sizeof(link_mode), &link_mode);
+        }
+
+        if (1) {
                 struct rtnl_link_ifmap map = {
                         .mem_start   = dev->mem_start,
                         .mem_end     = dev->mem_end,
@@ -399,6 +433,22 @@ static int do_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
                 dev->weight = *((u32 *) RTA_DATA(ida[IFLA_WEIGHT - 1]));
         }
 
+        if (ida[IFLA_OPERSTATE - 1]) {
+                if (ida[IFLA_OPERSTATE - 1]->rta_len != RTA_LENGTH(sizeof(u8)))
+                        goto out;
+
+                set_operstate(dev, *((u8 *) RTA_DATA(ida[IFLA_OPERSTATE - 1])));
+        }
+
+        if (ida[IFLA_LINKMODE - 1]) {
+                if (ida[IFLA_LINKMODE - 1]->rta_len != RTA_LENGTH(sizeof(u8)))
+                        goto out;
+
+                write_lock_bh(&dev_base_lock);
+                dev->link_mode = *((u8 *) RTA_DATA(ida[IFLA_LINKMODE - 1]));
+                write_unlock_bh(&dev_base_lock);
+        }
+
         if (ifm->ifi_index >= 0 && ida[IFLA_IFNAME - 1]) {
                 char ifname[IFNAMSIZ];