From: Yotam Gigi <yot...@mellanox.com>

Make the ipmr module register as a FIB notifier. To do that, implement both
the ipmr_seq_read and ipmr_dump ops.

The ipmr_seq_read op returns a sequence counter that is incremented on
every notification related operation done by the ipmr. To implement that,
add a sequence counter in the netns_ipv4 struct and increment it whenever a
new MFC route or VIF are added or deleted. The sequence operations are
protected by the RTNL lock.

The ipmr_dump iterates the list of MFC routes and the list of VIF entries
and sends notifications about them. The entries dump is done under RCU.

Signed-off-by: Yotam Gigi <yot...@mellanox.com>
Reviewed-by: Ido Schimmel <ido...@mellanox.com>
Signed-off-by: Jiri Pirko <j...@mellanox.com>
---
 include/linux/mroute.h   |  15 ++++++
 include/net/netns/ipv4.h |   3 ++
 net/ipv4/ipmr.c          | 135 ++++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 151 insertions(+), 2 deletions(-)

diff --git a/include/linux/mroute.h b/include/linux/mroute.h
index 2f88e3d..ba5a976 100644
--- a/include/linux/mroute.h
+++ b/include/linux/mroute.h
@@ -5,6 +5,7 @@
 #include <linux/pim.h>
 #include <linux/rhashtable.h>
 #include <net/sock.h>
+#include <net/fib_notifier.h>
 #include <uapi/linux/mroute.h>
 
 #ifdef CONFIG_IP_MROUTE
@@ -58,6 +59,14 @@ struct vif_device {
        int             link;                   /* Physical interface index     
*/
 };
 
+struct vif_entry_notifier_info {
+       struct fib_notifier_info info;
+       struct net_device *dev;
+       vifi_t vif_index;
+       unsigned short vif_flags;
+       u32 tb_id;
+};
+
 #define VIFF_STATIC 0x8000
 
 #define VIF_EXISTS(_mrt, _idx) ((_mrt)->vif_table[_idx].dev != NULL)
@@ -145,6 +154,12 @@ struct mfc_cache {
        struct rcu_head rcu;
 };
 
+struct mfc_entry_notifier_info {
+       struct fib_notifier_info info;
+       struct mfc_cache *mfc;
+       u32 tb_id;
+};
+
 struct rtmsg;
 int ipmr_get_route(struct net *net, struct sk_buff *skb,
                   __be32 saddr, __be32 daddr,
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 20d061c..5921496 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -162,6 +162,9 @@ struct netns_ipv4 {
        struct fib_notifier_ops *notifier_ops;
        unsigned int    fib_seq;        /* protected by rtnl_mutex */
 
+       struct fib_notifier_ops *ipmr_notifier_ops;
+       unsigned int    ipmr_seq;       /* protected by rtnl_mutex */
+
        atomic_t        rt_genid;
 };
 #endif
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 86dc5f9..9d331a74 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -264,6 +264,16 @@ static void __net_exit ipmr_rules_exit(struct net *net)
        fib_rules_unregister(net->ipv4.mr_rules_ops);
        rtnl_unlock();
 }
+
+static int ipmr_rules_dump(struct net *net, struct notifier_block *nb)
+{
+       return fib_rules_dump(net, nb, RTNL_FAMILY_IPMR);
+}
+
+static unsigned int ipmr_rules_seq_read(struct net *net)
+{
+       return fib_rules_seq_read(net, RTNL_FAMILY_IPMR);
+}
 #else
 #define ipmr_for_each_table(mrt, net) \
        for (mrt = net->ipv4.mrt; mrt; mrt = NULL)
@@ -298,6 +308,16 @@ static void __net_exit ipmr_rules_exit(struct net *net)
        net->ipv4.mrt = NULL;
        rtnl_unlock();
 }
+
+static int ipmr_rules_dump(struct net *net, struct notifier_block *nb)
+{
+       return 0;
+}
+
+static unsigned int ipmr_rules_seq_read(struct net *net)
+{
+       return 0;
+}
 #endif
 
 static inline int ipmr_hash_cmp(struct rhashtable_compare_arg *arg,
@@ -587,6 +607,43 @@ static struct net_device *ipmr_reg_vif(struct net *net, 
struct mr_table *mrt)
 }
 #endif
 
+static int call_ipmr_vif_entry_notifier(struct notifier_block *nb,
+                                       struct net *net,
+                                       enum fib_event_type event_type,
+                                       struct vif_device *vif,
+                                       vifi_t vif_index, u32 tb_id)
+{
+       struct vif_entry_notifier_info info = {
+               .info = {
+                       .family = RTNL_FAMILY_IPMR,
+                       .net = net,
+               },
+               .dev = vif->dev,
+               .vif_index = vif_index,
+               .vif_flags = vif->flags,
+               .tb_id = tb_id,
+       };
+
+       return call_fib_notifier(nb, net, event_type, &info.info);
+}
+
+static int call_ipmr_mfc_entry_notifier(struct notifier_block *nb,
+                                       struct net *net,
+                                       enum fib_event_type event_type,
+                                       struct mfc_cache *mfc, u32 tb_id)
+{
+       struct mfc_entry_notifier_info info = {
+               .info = {
+                       .family = RTNL_FAMILY_IPMR,
+                       .net = net,
+               },
+               .mfc = mfc,
+               .tb_id = tb_id
+       };
+
+       return call_fib_notifier(nb, net, event_type, &info.info);
+}
+
 /**
  *     vif_delete - Delete a VIF entry
  *     @notify: Set to 1, if the caller is a notifier_call
@@ -3050,14 +3107,85 @@ static const struct net_protocol pim_protocol = {
 };
 #endif
 
+static unsigned int ipmr_seq_read(struct net *net)
+{
+       ASSERT_RTNL();
+
+       return net->ipv4.ipmr_seq + ipmr_rules_seq_read(net);
+}
+
+static int ipmr_dump(struct net *net, struct notifier_block *nb)
+{
+       struct mr_table *mrt;
+       int err;
+
+       err = ipmr_rules_dump(net, nb);
+       if (err)
+               return err;
+
+       ipmr_for_each_table(mrt, net) {
+               struct vif_device *v = &mrt->vif_table[0];
+               struct mfc_cache *mfc;
+               int vifi;
+
+               /* Notifiy on table VIF entries */
+               for (vifi = 0; vifi < mrt->maxvif; vifi++, v++) {
+                       if (!v->dev)
+                               continue;
+
+                       call_ipmr_vif_entry_notifier(nb, net, FIB_EVENT_VIF_ADD,
+                                                    v, vifi, mrt->id);
+               }
+
+               /* Notify on table MFC entries */
+               list_for_each_entry_rcu(mfc, &mrt->mfc_cache_list, list)
+                       call_ipmr_mfc_entry_notifier(nb, net,
+                                                    FIB_EVENT_ENTRY_ADD, mfc,
+                                                    mrt->id);
+       }
+
+       return 0;
+}
+
+static const struct fib_notifier_ops ipmr_notifier_ops_template = {
+       .family         = RTNL_FAMILY_IPMR,
+       .fib_seq_read   = ipmr_seq_read,
+       .fib_dump       = ipmr_dump,
+       .owner          = THIS_MODULE,
+};
+
+int __net_init ipmr_notifier_init(struct net *net)
+{
+       struct fib_notifier_ops *ops;
+
+       net->ipv4.ipmr_seq = 0;
+
+       ops = fib_notifier_ops_register(&ipmr_notifier_ops_template, net);
+       if (IS_ERR(ops))
+               return PTR_ERR(ops);
+       net->ipv4.ipmr_notifier_ops = ops;
+
+       return 0;
+}
+
+static void __net_exit ipmr_notifier_exit(struct net *net)
+{
+       fib_notifier_ops_unregister(net->ipv4.ipmr_notifier_ops);
+       net->ipv4.ipmr_notifier_ops = NULL;
+}
+
 /* Setup for IP multicast routing */
 static int __net_init ipmr_net_init(struct net *net)
 {
        int err;
 
+       err = ipmr_notifier_init(net);
+       if (err)
+               goto ipmr_notifier_fail;
+
        err = ipmr_rules_init(net);
        if (err < 0)
-               goto fail;
+               goto ipmr_rules_fail;
 
 #ifdef CONFIG_PROC_FS
        err = -ENOMEM;
@@ -3074,7 +3202,9 @@ static int __net_init ipmr_net_init(struct net *net)
 proc_vif_fail:
        ipmr_rules_exit(net);
 #endif
-fail:
+ipmr_rules_fail:
+       ipmr_notifier_exit(net);
+ipmr_notifier_fail:
        return err;
 }
 
@@ -3084,6 +3214,7 @@ static void __net_exit ipmr_net_exit(struct net *net)
        remove_proc_entry("ip_mr_cache", net->proc_net);
        remove_proc_entry("ip_mr_vif", net->proc_net);
 #endif
+       ipmr_notifier_exit(net);
        ipmr_rules_exit(net);
 }
 
-- 
2.9.5

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