[BRIDGE]: netlink interface for link management

Add basic netlink support to the Ethernet bridge. Including:
 * dump interfaces in bridges
 * monitor link status changes
 * change state of bridge port

For some demo programs see:
	http://developer.osdl.org/shemminger/prototypes/brnl.tar.gz

These are to allow building a daemon that does alternative
implementations of Spanning Tree Protocol.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/bridge/Makefile b/net/bridge/Makefile
index 59556e40e143457abdf3ab0d4af6b609796b2264..f444c12cde5a66d0cf864ef2238de8307d8b2707 100644 (file)
--- a/net/bridge/Makefile
+++ b/net/bridge/Makefile
@@ -6,7 +6,7 @@ obj-$(CONFIG_BRIDGE) += bridge.o
 
 bridge-y       := br.o br_device.o br_fdb.o br_forward.o br_if.o br_input.o \
                        br_ioctl.o br_notify.o br_stp.o br_stp_bpdu.o \
-                       br_stp_if.o br_stp_timer.o
+                       br_stp_if.o br_stp_timer.o br_netlink.o
 
 bridge-$(CONFIG_SYSFS) += br_sysfs_if.o br_sysfs_br.o
 

diff --git a/net/bridge/br.c b/net/bridge/br.c
index 558d27204f60c32c9ce0a69bdb379dde58e3dc8d..654401ceb2dbdf679522c8ce92c5699c5589c613 100644 (file)
--- a/net/bridge/br.c
+++ b/net/bridge/br.c
@@ -48,6 +48,7 @@ static int __init br_init(void)
        if (err)
                goto err_out2;
 
+       br_netlink_init();
        brioctl_set(br_ioctl_deviceless_stub);
        br_handle_frame_hook = br_handle_frame;
 
@@ -67,6 +68,7 @@ static void __exit br_deinit(void)
 {
        rcu_assign_pointer(br_stp_sap->rcv_func, NULL);
 
+       br_netlink_fini();
        br_netfilter_fini();
        unregister_netdevice_notifier(&br_device_notifier);
        brioctl_set(NULL);

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
new file mode 100644 (file)
index 0000000..881d7d1
--- /dev/null
+++ b/net/bridge/br_netlink.c
@@ -0,0 +1,199 @@
+/*
+ *     Bridge netlink control interface
+ *
+ *     Authors:
+ *     Stephen Hemminger               <shemminger@osdl.org>
+ *
+ *     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/kernel.h>
+#include <linux/rtnetlink.h>
+#include "br_private.h"
+
+/*
+ * Create one netlink message for one interface
+ * Contains port and master info as well as carrier and bridge state.
+ */
+static int br_fill_ifinfo(struct sk_buff *skb, const struct net_bridge_port *port,
+                         u32 pid, u32 seq, int event, unsigned int flags)
+{
+       const struct net_bridge *br = port->br;
+       const struct net_device *dev = port->dev;
+       struct ifinfomsg *r;
+       struct nlmsghdr *nlh;
+       unsigned char *b = skb->tail;
+       u32 mtu = dev->mtu;
+       u8 operstate = netif_running(dev) ? dev->operstate : IF_OPER_DOWN;
+       u8 portstate = port->state;
+
+       pr_debug("br_fill_info event %d port %s master %s\n",
+                event, dev->name, br->dev->name);
+
+       nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
+       r = NLMSG_DATA(nlh);
+       r->ifi_family = AF_BRIDGE;
+       r->__ifi_pad = 0;
+       r->ifi_type = dev->type;
+       r->ifi_index = dev->ifindex;
+       r->ifi_flags = dev_get_flags(dev);
+       r->ifi_change = 0;
+
+       RTA_PUT(skb, IFLA_IFNAME, strlen(dev->name)+1, dev->name);
+
+       RTA_PUT(skb, IFLA_MASTER, sizeof(int), &br->dev->ifindex);
+
+       if (dev->addr_len)
+               RTA_PUT(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr);
+
+       RTA_PUT(skb, IFLA_MTU, sizeof(mtu), &mtu);
+       if (dev->ifindex != dev->iflink)
+               RTA_PUT(skb, IFLA_LINK, sizeof(int), &dev->iflink);
+
+
+       RTA_PUT(skb, IFLA_OPERSTATE, sizeof(operstate), &operstate);
+
+       if (event == RTM_NEWLINK)
+               RTA_PUT(skb, IFLA_PROTINFO, sizeof(portstate), &portstate);
+
+       nlh->nlmsg_len = skb->tail - b;
+
+       return skb->len;
+
+nlmsg_failure:
+rtattr_failure:
+
+       skb_trim(skb, b - skb->data);
+       return -EINVAL;
+}
+
+/*
+ * Notify listeners of a change in port information
+ */
+void br_ifinfo_notify(int event, struct net_bridge_port *port)
+{
+       struct sk_buff *skb;
+       int err = -ENOMEM;
+
+       pr_debug("bridge notify event=%d\n", event);
+       skb = alloc_skb(NLMSG_SPACE(sizeof(struct ifinfomsg) + 128),
+                       GFP_ATOMIC);
+       if (!skb)
+               goto err_out;
+
+       err = br_fill_ifinfo(skb, port, current->pid, 0, event, 0);
+       if (err)
+               goto err_kfree;
+
+       NETLINK_CB(skb).dst_group = RTNLGRP_LINK;
+       netlink_broadcast(rtnl, skb, 0, RTNLGRP_LINK, GFP_ATOMIC);
+       return;
+
+err_kfree:
+       kfree_skb(skb);
+err_out:
+       netlink_set_err(rtnl, 0, RTNLGRP_LINK, err);
+}
+
+/*
+ * Dump information about all ports, in response to GETLINK
+ */
+static int br_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
+{
+       struct net_device *dev;
+       int idx;
+       int s_idx = cb->args[0];
+       int err = 0;
+
+       read_lock(&dev_base_lock);
+       for (dev = dev_base, idx = 0; dev; dev = dev->next) {
+               struct net_bridge_port *p = dev->br_port;
+
+               /* not a bridge port */
+               if (!p)
+                       continue;
+
+               if (idx < s_idx)
+                       continue;
+
+               err = br_fill_ifinfo(skb, p, NETLINK_CB(cb->skb).pid,
+                                    cb->nlh->nlmsg_seq, RTM_NEWLINK, NLM_F_MULTI);
+               if (err <= 0)
+                       break;
+               ++idx;
+       }
+       read_unlock(&dev_base_lock);
+
+       cb->args[0] = idx;
+
+       return skb->len;
+}
+
+/*
+ * Change state of port (ie from forwarding to blocking etc)
+ * Used by spanning tree in user space.
+ */
+static int br_rtm_setlink(struct sk_buff *skb,  struct nlmsghdr *nlh, void *arg)
+{
+       struct rtattr  **rta = arg;
+       struct ifinfomsg *ifm = NLMSG_DATA(nlh);
+       struct net_device *dev;
+       struct net_bridge_port *p;
+       u8 new_state;
+
+       if (ifm->ifi_family != AF_BRIDGE)
+               return -EPFNOSUPPORT;
+
+       /* Must pass valid state as PROTINFO */
+       if (rta[IFLA_PROTINFO-1]) {
+               u8 *pstate = RTA_DATA(rta[IFLA_PROTINFO-1]);
+               new_state = *pstate;
+       } else
+               return -EINVAL;
+
+       if (new_state > BR_STATE_BLOCKING)
+               return -EINVAL;
+
+       /* Find bridge port */
+       dev = __dev_get_by_index(ifm->ifi_index);
+       if (!dev)
+               return -ENODEV;
+
+       p = dev->br_port;
+       if (!p)
+               return -EINVAL;
+
+       /* if kernel STP is running, don't allow changes */
+       if (p->br->stp_enabled)
+               return -EBUSY;
+
+       if (!netif_running(dev))
+               return -ENETDOWN;
+
+       if (!netif_carrier_ok(dev) && new_state != BR_STATE_DISABLED)
+               return -ENETDOWN;
+
+       p->state = new_state;
+       br_log_state(p);
+       return 0;
+}
+
+
+static struct rtnetlink_link bridge_rtnetlink_table[RTM_NR_MSGTYPES] = {
+       [RTM_GETLINK - RTM_BASE] = { .dumpit    = br_dump_ifinfo, },
+       [RTM_SETLINK - RTM_BASE] = { .doit      = br_rtm_setlink, },
+};
+
+void __init br_netlink_init(void)
+{
+       rtnetlink_links[PF_BRIDGE] = bridge_rtnetlink_table;
+}
+
+void __exit br_netlink_fini(void)
+{
+       rtnetlink_links[PF_BRIDGE] = NULL;
+}
+

diff --git a/net/bridge/br_notify.c b/net/bridge/br_notify.c
index a43a9c1d50d7daa21c732523e9d2cdb3d36e3a9e..20278494e4da0d11712cfad0ed31f410abc5eb35 100644 (file)
--- a/net/bridge/br_notify.c
+++ b/net/bridge/br_notify.c
@@ -14,6 +14,7 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/rtnetlink.h>
 
 #include "br_private.h"
 
@@ -49,6 +50,7 @@ static int br_device_event(struct notifier_block *unused, unsigned long event, v
 
        case NETDEV_CHANGEADDR:
                br_fdb_changeaddr(p, dev->dev_addr);
+               br_ifinfo_notify(RTM_NEWLINK, p);
                br_stp_recalculate_bridge_id(br);
                break;
 

diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 22071d156828cca601c069336152861a92397e6c..c491fb2f280ebf7b1cf2395371c43d33bf36f43c 100644 (file)
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -29,7 +29,7 @@
 
 #define BR_PORT_DEBOUNCE (HZ/10)
 
-#define BR_VERSION     "2.1"
+#define BR_VERSION     "2.2"
 
 typedef struct bridge_id bridge_id;
 typedef struct mac_addr mac_addr;
@@ -237,6 +237,11 @@ extern struct net_bridge_fdb_entry *(*br_fdb_get_hook)(struct net_bridge *br,
 extern void (*br_fdb_put_hook)(struct net_bridge_fdb_entry *ent);
 
 
+/* br_netlink.c */
+extern void br_netlink_init(void);
+extern void br_netlink_fini(void);
+extern void br_ifinfo_notify(int event, struct net_bridge_port *port);
+
 #ifdef CONFIG_SYSFS
 /* br_sysfs_if.c */
 extern struct sysfs_ops brport_sysfs_ops;

diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c
index 23dea1422c9a90873c13145ae52f7287afcb9633..14cd025079af0393abba67e7c3704dc2bd688470 100644 (file)
--- a/net/bridge/br_stp_if.c
+++ b/net/bridge/br_stp_if.c
@@ -16,6 +16,7 @@
 #include <linux/kernel.h>
 #include <linux/smp_lock.h>
 #include <linux/etherdevice.h>
+#include <linux/rtnetlink.h>
 
 #include "br_private.h"
 #include "br_private_stp.h"
@@ -86,6 +87,7 @@ void br_stp_disable_bridge(struct net_bridge *br)
 void br_stp_enable_port(struct net_bridge_port *p)
 {
        br_init_port(p);
+       br_ifinfo_notify(RTM_NEWLINK, p);
        br_port_state_selection(p->br);
 }
 
@@ -99,6 +101,8 @@ void br_stp_disable_port(struct net_bridge_port *p)
        printk(KERN_INFO "%s: port %i(%s) entering %s state\n",
               br->dev->name, p->port_no, p->dev->name, "disabled");
 
+       br_ifinfo_notify(RTM_DELLINK, p);
+
        wasroot = br_is_root_bridge(br);
        br_become_designated_port(p);
        p->state = BR_STATE_DISABLED;