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Patch resubmission: RFC2863 operstatus for 2.5.49

To: davem@xxxxxxxxxx
Subject: Patch resubmission: RFC2863 operstatus for 2.5.49
From: Stefan Rompf <srompf@xxxxxx>
Date: Tue, 26 Nov 2002 10:22:53 +0100
Cc: netdev@xxxxxxxxxxx
Sender: netdev-bounce@xxxxxxxxxxx
Hi David,

I've updated my RFC2863 operstatus and userspace forwarding patch to
2.5.49. As discussion on netdev seems to be complete, I need some
comment from your side.

Stefan
diff -uprNX dontdiff linux-2.5.49/include/linux/netdevice.h 
linux-2.5.49-lw/include/linux/netdevice.h
--- linux-2.5.49/include/linux/netdevice.h      2002-11-22 22:41:08.000000000 
+0100
+++ linux-2.5.49-lw/include/linux/netdevice.h   2002-11-25 22:52:29.000000000 
+0100
@@ -204,10 +204,23 @@ enum netdev_state_t
 {
        __LINK_STATE_XOFF=0,
        __LINK_STATE_START,
-       __LINK_STATE_PRESENT,
+       __LINK_STATE_PRESENT_OBSOLETE,
        __LINK_STATE_SCHED,
-       __LINK_STATE_NOCARRIER,
-       __LINK_STATE_RX_SCHED
+       __LINK_STATE_NOCARRIER_OBSOLETE,
+       __LINK_STATE_RX_SCHED,
+       __LINK_STATE_LINKWATCH_PENDING
+};
+
+
+/* Device operative state as per RFC2863 */
+enum netdev_operstate_t {
+       NETDEV_OPER_UP = 1,
+       NETDEV_OPER_DOWN, /* Obsoletes LINK_STATE_NOCARRIER */
+       NETDEV_OPER_TESTING,
+       NETDEV_OPER_UNKNOWN,
+       NETDEV_OPER_DORMANT,
+       NETDEV_OPER_NOTPRESENT, /* Obsoletes !LINK_STATE_PRESENT */
+       NETDEV_OPER_LOWERDOWN
 };
 
 
@@ -308,6 +321,10 @@ struct net_device
                                          * which this device is member of.
                                          */
 
+       /* Operative state, access semaphore */
+       rwlock_t                operstate_lock;
+       unsigned char           operstate;
+
        /* Interface address info. */
        unsigned char           broadcast[MAX_ADDR_LEN];        /* hw bcast add 
*/
        unsigned char           dev_addr[MAX_ADDR_LEN]; /* hw address   */
@@ -631,34 +648,76 @@ static inline void dev_put(struct net_de
  * who is responsible for serialization of these calls.
  */
 
+#ifdef CONFIG_LINKWATCH
+extern void linkwatch_fire_event(struct net_device *dev);
+#endif
+
+static inline unsigned char netif_set_operstate(struct net_device *dev, 
unsigned char newstate)
+{
+       unsigned long flags;
+       unsigned char oldstate;
+
+       write_lock_irqsave(&dev->operstate_lock, flags);
+       oldstate = dev->operstate;
+       dev->operstate = newstate;
+       write_unlock_irqrestore(&dev->operstate_lock, flags);
+
+#ifdef CONFIG_LINKWATCH
+       if (oldstate != newstate) linkwatch_fire_event(dev);
+#endif
+
+       return oldstate;
+}
+
+static inline unsigned char netif_get_operstate(struct net_device *dev)
+{
+       unsigned long flags;
+       unsigned char state;
+
+       read_lock_irqsave(&dev->operstate_lock, flags);
+       state = dev->operstate;
+       read_unlock_irqrestore(&dev->operstate_lock, flags);
+
+       return state;
+}
+
 static inline int netif_carrier_ok(struct net_device *dev)
 {
-       return !test_bit(__LINK_STATE_NOCARRIER, &dev->state);
+       return netif_get_operstate(dev) != NETDEV_OPER_UP;
+}
+
+static inline int netif_operstate_to_iff_running(struct net_device *dev)
+{
+       unsigned char state = netif_get_operstate(dev);
+
+       return((1 << state) &
+              (1 << NETDEV_OPER_UP | 1 << NETDEV_OPER_UNKNOWN));
 }
 
 extern void __netdev_watchdog_up(struct net_device *dev);
 
+
 static inline void netif_carrier_on(struct net_device *dev)
 {
-       clear_bit(__LINK_STATE_NOCARRIER, &dev->state);
+       netif_set_operstate(dev, NETDEV_OPER_UP);
        if (netif_running(dev))
                __netdev_watchdog_up(dev);
 }
 
 static inline void netif_carrier_off(struct net_device *dev)
 {
-       set_bit(__LINK_STATE_NOCARRIER, &dev->state);
+       netif_set_operstate(dev, NETDEV_OPER_DOWN);
 }
 
 /* Hot-plugging. */
 static inline int netif_device_present(struct net_device *dev)
 {
-       return test_bit(__LINK_STATE_PRESENT, &dev->state);
+       return netif_get_operstate(dev) != NETDEV_OPER_NOTPRESENT;
 }
 
 static inline void netif_device_detach(struct net_device *dev)
 {
-       if (test_and_clear_bit(__LINK_STATE_PRESENT, &dev->state) &&
+       if (netif_set_operstate(dev, NETDEV_OPER_NOTPRESENT) != 
NETDEV_OPER_NOTPRESENT &&
            netif_running(dev)) {
                netif_stop_queue(dev);
        }
@@ -666,7 +725,7 @@ static inline void netif_device_detach(s
 
 static inline void netif_device_attach(struct net_device *dev)
 {
-       if (!test_and_set_bit(__LINK_STATE_PRESENT, &dev->state) &&
+       if (netif_set_operstate(dev, NETDEV_OPER_UNKNOWN) == 
NETDEV_OPER_NOTPRESENT &&
            netif_running(dev)) {
                netif_wake_queue(dev);
                __netdev_watchdog_up(dev);
diff -uprNX dontdiff linux-2.5.49/net/Kconfig linux-2.5.49-lw/net/Kconfig
--- linux-2.5.49/net/Kconfig    2002-11-22 22:40:16.000000000 +0100
+++ linux-2.5.49-lw/net/Kconfig 2002-11-25 22:58:39.000000000 +0100
@@ -265,6 +265,20 @@ config ATM_MPOA
 config VLAN_8021Q
        tristate "802.1Q VLAN Support"
 
+config LINKWATCH
+       bool "Device link state notification (EXPERIMENTAL)"
+       depends on EXPERIMENTAL
+       help
+         When this option is enabled, the kernel will forward changes in the
+         operative ("RUNNING") state of an interface via the netlink socket.
+         This is most useful when running linux as a router.
+       
+         Note that currently not many drivers support this, compliant ones
+         can be found by watching the the RUNNING flag in ifconfig output
+         that should follow operative state.
+       
+         If unsure, say 'N'.
+
 config LLC
        tristate "ANSI/IEEE 802.2 - aka LLC (IPX, Appletalk, Token Ring)"
        help
diff -uprNX dontdiff linux-2.5.49/net/core/Makefile 
linux-2.5.49-lw/net/core/Makefile
--- linux-2.5.49/net/core/Makefile      2002-11-22 22:41:08.000000000 +0100
+++ linux-2.5.49-lw/net/core/Makefile   2002-11-25 22:52:33.000000000 +0100
@@ -22,4 +22,6 @@ obj-$(CONFIG_NET_RADIO) += wireless.o
 # Ugly. I wish all wireless drivers were moved in drivers/net/wireless
 obj-$(CONFIG_NET_PCMCIA_RADIO) += wireless.o
 
+obj-$(CONFIG_LINKWATCH) += link_watch.o
+
 include $(TOPDIR)/Rules.make
diff -uprNX dontdiff linux-2.5.49/net/core/dev.c linux-2.5.49-lw/net/core/dev.c
--- linux-2.5.49/net/core/dev.c 2002-11-22 22:40:43.000000000 +0100
+++ linux-2.5.49-lw/net/core/dev.c      2002-11-25 22:52:33.000000000 +0100
@@ -199,7 +199,6 @@ int netdev_fastroute;
 int netdev_fastroute_obstacles;
 #endif
 
-
 
/*******************************************************************************
 
                Protocol management and registration routines
@@ -262,6 +261,9 @@ void dev_add_pack(struct packet_type *pt
        br_write_unlock_bh(BR_NETPROTO_LOCK);
 }
 
+#ifdef CONFIG_LINKWATCH
+void linkwatch_run_queue(void);
+#endif
 
 /**
  *     dev_remove_pack  - remove packet handler
@@ -2018,7 +2020,7 @@ static int dev_ifsioc(struct ifreq *ifr,
                                                         IFF_RUNNING)) | 
                                         (dev->gflags & (IFF_PROMISC |
                                                         IFF_ALLMULTI));
-                       if (netif_running(dev) && netif_carrier_ok(dev))
+                       if (netif_running(dev) && 
netif_operstate_to_iff_running(dev))
                                ifr->ifr_flags |= IFF_RUNNING;
                        return 0;
 
@@ -2433,6 +2435,10 @@ int register_netdevice(struct net_device
                goto out;
 #endif /* CONFIG_NET_DIVERT */
 
+       /* Initial operstate */
+       dev->operstate_lock = RW_LOCK_UNLOCKED;
+       dev->operstate = NETDEV_OPER_UNKNOWN;
+
        dev->iflink = -1;
 
        /* Init, if this function is available */
@@ -2458,13 +2464,6 @@ int register_netdevice(struct net_device
        if (!dev->rebuild_header)
                dev->rebuild_header = default_rebuild_header;
 
-       /*
-        *      Default initial state at registry is that the
-        *      device is present.
-        */
-
-       set_bit(__LINK_STATE_PRESENT, &dev->state);
-
        dev->next = NULL;
        dev_init_scheduler(dev);
        write_lock_bh(&dev_base_lock);
@@ -2642,6 +2641,17 @@ int unregister_netdevice(struct net_devi
                        /* Rebroadcast unregister notification */
                        notifier_call_chain(&netdev_chain,
                                            NETDEV_UNREGISTER, dev);
+
+#ifdef CONFIG_LINKWATCH
+                       if (test_bit(__LINK_STATE_LINKWATCH_PENDING, 
&dev->state)) {
+                               /* We must not have linkwatch events pending
+                                * on unregister. If this happens, we simply
+                                * run the queue unscheduled, resulting in a
+                                * noop for this device
+                                */
+                               linkwatch_run_queue();
+                       }
+#endif
                }
                current->state = TASK_INTERRUPTIBLE;
                schedule_timeout(HZ / 4);
@@ -2736,6 +2746,8 @@ static int __init net_dev_init(void)
 #ifdef CONFIG_NET_FASTROUTE
                dev->fastpath_lock = RW_LOCK_UNLOCKED;
 #endif
+               dev->operstate_lock = RW_LOCK_UNLOCKED;
+               dev->operstate = NETDEV_OPER_UNKNOWN;
                dev->xmit_lock_owner = -1;
                dev->iflink = -1;
                dev_hold(dev);
@@ -2768,7 +2780,6 @@ static int __init net_dev_init(void)
                        if (!dev->rebuild_header)
                                dev->rebuild_header = default_rebuild_header;
                        dev_init_scheduler(dev);
-                       set_bit(__LINK_STATE_PRESENT, &dev->state);
                }
        }
 
@@ -2849,3 +2860,5 @@ static int net_run_sbin_hotplug(struct n
        return call_usermodehelper(argv [0], argv, envp);
 }
 #endif
+
+
diff -uprNX dontdiff linux-2.5.49/net/core/link_watch.c 
linux-2.5.49-lw/net/core/link_watch.c
--- linux-2.5.49/net/core/link_watch.c  1970-01-01 01:00:00.000000000 +0100
+++ linux-2.5.49-lw/net/core/link_watch.c       2002-11-25 22:52:33.000000000 
+0100
@@ -0,0 +1,134 @@
+/*
+ * Linux network device link state notifaction
+ *
+ * Author:
+ *     Stefan Rompf <sux@xxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/workqueue.h>
+#include <linux/config.h>
+#include <linux/netdevice.h>
+#include <linux/if.h>
+#include <linux/rtnetlink.h>
+#include <linux/jiffies.h>
+#include <linux/spinlock.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+#include <asm/bitops.h>
+#include <asm/types.h>
+
+
+enum lw_bits {
+       LW_RUNNING = 0,
+       LW_SE_USED
+};
+
+static unsigned long linkwatch_flags = 0;
+static unsigned long linkwatch_nextevent = 0;
+
+static void linkwatch_event(void *dummy);
+static DECLARE_WORK(linkwatch_work, linkwatch_event, NULL);
+
+static LIST_HEAD(lweventlist);
+static spinlock_t lweventlist_lock = SPIN_LOCK_UNLOCKED;
+
+struct lw_event {
+       struct list_head list;
+       struct net_device *dev;
+};
+
+/* Avoid kmalloc() for most systems */
+struct lw_event singleevent;
+
+/* Must be called with the rtnl semaphore held */
+void linkwatch_run_queue(void) {
+       LIST_HEAD(head);
+       struct list_head *n, *next;
+
+       spin_lock_irq(&lweventlist_lock);
+       list_splice_init(&lweventlist, &head);
+       spin_unlock_irq(&lweventlist_lock);
+
+       list_for_each_safe(n, next, &head) {
+               struct lw_event *event = list_entry(n, struct lw_event, list);
+               struct net_device *dev = event->dev;
+
+               if (event == &singleevent) {
+                       clear_bit(LW_SE_USED, &linkwatch_flags);
+               } else {
+                       kfree(event);
+               }
+
+               /* We are about to handle this device,
+                * so new events can be accepted
+                */
+               clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state);
+
+               if (dev->flags & IFF_UP) {
+                       netdev_state_change(dev);
+               }
+
+               dev_put(dev);
+       }
+}       
+
+
+static void linkwatch_event(void *dummy)
+{
+       /* Limit the number of linkwatch events to one
+        * per second so that a runaway driver does not
+        * cause a storm of messages on the netlink
+        * socket
+        */     
+       linkwatch_nextevent = jiffies + HZ;
+       clear_bit(LW_RUNNING, &linkwatch_flags);
+
+       rtnl_lock();
+       linkwatch_run_queue();
+       rtnl_unlock();
+}
+
+
+void linkwatch_fire_event(struct net_device *dev)
+{
+       if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) {
+               unsigned long flags;
+               struct lw_event *event;
+
+               if (test_and_set_bit(LW_SE_USED, &linkwatch_flags)) {
+                       event = kmalloc(sizeof(struct lw_event), GFP_ATOMIC);
+
+                       if (unlikely(event == NULL)) {
+                               clear_bit(__LINK_STATE_LINKWATCH_PENDING, 
&dev->state);
+                               return;
+                       }
+               } else {
+                       event = &singleevent;
+               }
+
+               dev_hold(dev);
+               event->dev = dev;
+
+               spin_lock_irqsave(&lweventlist_lock, flags);
+               list_add_tail(&event->list, &lweventlist);
+               spin_unlock_irqrestore(&lweventlist_lock, flags);
+
+               if (!test_and_set_bit(LW_RUNNING, &linkwatch_flags)) {
+                       unsigned long thisevent = jiffies;
+
+                       if (thisevent >= linkwatch_nextevent) {
+                               schedule_work(&linkwatch_work);
+                       } else {
+                               schedule_delayed_work(&linkwatch_work, 
linkwatch_nextevent - thisevent);
+                       }
+               }
+       }
+}
+
diff -uprNX dontdiff linux-2.5.49/net/core/rtnetlink.c 
linux-2.5.49-lw/net/core/rtnetlink.c
--- linux-2.5.49/net/core/rtnetlink.c   2002-11-22 22:41:13.000000000 +0100
+++ linux-2.5.49-lw/net/core/rtnetlink.c        2002-11-25 22:52:33.000000000 
+0100
@@ -165,7 +165,7 @@ static int rtnetlink_fill_ifinfo(struct 
        r->ifi_flags = dev->flags;
        r->ifi_change = change;
 
-       if (!netif_running(dev) || !netif_carrier_ok(dev))
+       if (!netif_running(dev) || !netif_operstate_to_iff_running(dev))
                r->ifi_flags &= ~IFF_RUNNING;
        else
                r->ifi_flags |= IFF_RUNNING;
diff -uprNX dontdiff linux-2.5.49/net/netsyms.c linux-2.5.49-lw/net/netsyms.c
--- linux-2.5.49/net/netsyms.c  2002-11-22 22:40:39.000000000 +0100
+++ linux-2.5.49-lw/net/netsyms.c       2002-11-25 22:52:33.000000000 +0100
@@ -632,4 +632,8 @@ extern void wireless_send_event(struct n
 EXPORT_SYMBOL(wireless_send_event);
 #endif /* CONFIG_NET_RADIO || CONFIG_NET_PCMCIA_RADIO */
 
+#ifdef CONFIG_LINKWATCH
+EXPORT_SYMBOL(linkwatch_fire_event);
+#endif
+
 #endif  /* CONFIG_NET */

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