1 files changed, 225 insertions, 203 deletions

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 179fcab866fc..86dd5691af46 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -75,7 +75,7 @@ struct mr_table {
         struct net              *net;
 #endif
         u32                     id;
-        struct sock             *mroute_sk;
+        struct sock __rcu       *mroute_sk;
         struct timer_list       ipmr_expire_timer;
         struct list_head        mfc_unres_queue;
         struct list_head        mfc_cache_array[MFC_LINES];
@@ -98,7 +98,7 @@ struct ipmr_result {
 };
 
 /* Big lock, protecting vif table, mrt cache and mroute socket state.
-   Note that the changes are semaphored via rtnl_lock.
+ * Note that the changes are semaphored via rtnl_lock.
  */
 
 static DEFINE_RWLOCK(mrt_lock);
@@ -113,11 +113,11 @@ static DEFINE_RWLOCK(mrt_lock);
 static DEFINE_SPINLOCK(mfc_unres_lock);
 
 /* We return to original Alan's scheme. Hash table of resolved
-   entries is changed only in process context and protected
-   with weak lock mrt_lock. Queue of unresolved entries is protected
-   with strong spinlock mfc_unres_lock.
-
-   In this case data path is free of exclusive locks at all.
+ * entries is changed only in process context and protected
+ * with weak lock mrt_lock. Queue of unresolved entries is protected
+ * with strong spinlock mfc_unres_lock.
+ *
+ * In this case data path is free of exclusive locks at all.
  */
 
 static struct kmem_cache *mrt_cachep __read_mostly;
@@ -396,9 +396,9 @@ struct net_device *ipmr_new_tunnel(struct net *net, struct vifctl *v)
                         set_fs(KERNEL_DS);
                         err = ops->ndo_do_ioctl(dev, &ifr, SIOCADDTUNNEL);
                         set_fs(oldfs);
-                } else
+                } else {
                         err = -EOPNOTSUPP;
-
+                }
                 dev = NULL;
 
                 if (err == 0 &&
@@ -495,7 +495,8 @@ static struct net_device *ipmr_reg_vif(struct net *net, struct mr_table *mrt)
         dev->iflink = 0;
 
         rcu_read_lock();
-        if ((in_dev = __in_dev_get_rcu(dev)) == NULL) {
+        in_dev = __in_dev_get_rcu(dev);
+        if (!in_dev) {
                 rcu_read_unlock();
                 goto failure;
         }
@@ -552,9 +553,10 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify,
                 mrt->mroute_reg_vif_num = -1;
 #endif
 
-        if (vifi+1 == mrt->maxvif) {
+        if (vifi + 1 == mrt->maxvif) {
                 int tmp;
-                for (tmp=vifi-1; tmp>=0; tmp--) {
+
+                for (tmp = vifi - 1; tmp >= 0; tmp--) {
                         if (VIF_EXISTS(mrt, tmp))
                                 break;
                 }
@@ -565,25 +567,33 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify,
 
         dev_set_allmulti(dev, -1);
 
-        if ((in_dev = __in_dev_get_rtnl(dev)) != NULL) {
+        in_dev = __in_dev_get_rtnl(dev);
+        if (in_dev) {
                 IPV4_DEVCONF(in_dev->cnf, MC_FORWARDING)--;
                 ip_rt_multicast_event(in_dev);
         }
 
-        if (v->flags&(VIFF_TUNNEL|VIFF_REGISTER) && !notify)
+        if (v->flags & (VIFF_TUNNEL | VIFF_REGISTER) && !notify)
                 unregister_netdevice_queue(dev, head);
 
         dev_put(dev);
         return 0;
 }
 
-static inline void ipmr_cache_free(struct mfc_cache *c)
+static void ipmr_cache_free_rcu(struct rcu_head *head)
 {
+        struct mfc_cache *c = container_of(head, struct mfc_cache, rcu);
+
         kmem_cache_free(mrt_cachep, c);
 }
 
+static inline void ipmr_cache_free(struct mfc_cache *c)
+{
+        call_rcu(&c->rcu, ipmr_cache_free_rcu);
+}
+
 /* Destroy an unresolved cache entry, killing queued skbs
-   and reporting error to netlink readers.
+ * and reporting error to netlink readers.
  */
 
 static void ipmr_destroy_unres(struct mr_table *mrt, struct mfc_cache *c)
@@ -605,8 +615,9 @@ static void ipmr_destroy_unres(struct mr_table *mrt, struct mfc_cache *c)
                         memset(&e->msg, 0, sizeof(e->msg));
 
                         rtnl_unicast(skb, net, NETLINK_CB(skb).pid);
-                } else
+                } else {
                         kfree_skb(skb);
+                }
         }
 
         ipmr_cache_free(c);
@@ -724,13 +735,13 @@ static int vif_add(struct net *net, struct mr_table *mrt,
         case 0:
                 if (vifc->vifc_flags == VIFF_USE_IFINDEX) {
                         dev = dev_get_by_index(net, vifc->vifc_lcl_ifindex);
-                        if (dev && dev->ip_ptr == NULL) {
+                        if (dev && __in_dev_get_rtnl(dev) == NULL) {
                                 dev_put(dev);
                                 return -EADDRNOTAVAIL;
                         }
-                } else
+                } else {
                         dev = ip_dev_find(net, vifc->vifc_lcl_addr.s_addr);
-
+                }
                 if (!dev)
                         return -EADDRNOTAVAIL;
                 err = dev_set_allmulti(dev, 1);
@@ -743,16 +754,16 @@ static int vif_add(struct net *net, struct mr_table *mrt,
                 return -EINVAL;
         }
 
-        if ((in_dev = __in_dev_get_rtnl(dev)) == NULL) {
+        in_dev = __in_dev_get_rtnl(dev);
+        if (!in_dev) {
                 dev_put(dev);
                 return -EADDRNOTAVAIL;
         }
         IPV4_DEVCONF(in_dev->cnf, MC_FORWARDING)++;
         ip_rt_multicast_event(in_dev);
 
-        /*
-         *      Fill in the VIF structures
-         */
+        /* Fill in the VIF structures */
+
         v->rate_limit = vifc->vifc_rate_limit;
         v->local = vifc->vifc_lcl_addr.s_addr;
         v->remote = vifc->vifc_rmt_addr.s_addr;
@@ -765,14 +776,14 @@ static int vif_add(struct net *net, struct mr_table *mrt,
         v->pkt_in = 0;
         v->pkt_out = 0;
         v->link = dev->ifindex;
-        if (v->flags&(VIFF_TUNNEL|VIFF_REGISTER))
+        if (v->flags & (VIFF_TUNNEL | VIFF_REGISTER))
                 v->link = dev->iflink;
 
         /* And finish update writing critical data */
         write_lock_bh(&mrt_lock);
         v->dev = dev;
 #ifdef CONFIG_IP_PIMSM
-        if (v->flags&VIFF_REGISTER)
+        if (v->flags & VIFF_REGISTER)
                 mrt->mroute_reg_vif_num = vifi;
 #endif
         if (vifi+1 > mrt->maxvif)
@@ -781,6 +792,7 @@ static int vif_add(struct net *net, struct mr_table *mrt,
         return 0;
 }
 
+/* called with rcu_read_lock() */
 static struct mfc_cache *ipmr_cache_find(struct mr_table *mrt,
                                          __be32 origin,
                                          __be32 mcastgrp)
@@ -788,7 +800,7 @@ static struct mfc_cache *ipmr_cache_find(struct mr_table *mrt,
         int line = MFC_HASH(mcastgrp, origin);
         struct mfc_cache *c;
 
-        list_for_each_entry(c, &mrt->mfc_cache_array[line], list) {
+        list_for_each_entry_rcu(c, &mrt->mfc_cache_array[line], list) {
                 if (c->mfc_origin == origin && c->mfc_mcastgrp == mcastgrp)
                         return c;
         }
@@ -801,19 +813,20 @@ static struct mfc_cache *ipmr_cache_find(struct mr_table *mrt,
 static struct mfc_cache *ipmr_cache_alloc(void)
 {
         struct mfc_cache *c = kmem_cache_zalloc(mrt_cachep, GFP_KERNEL);
-        if (c == NULL)
-                return NULL;
-        c->mfc_un.res.minvif = MAXVIFS;
+
+        if (c)
+                c->mfc_un.res.minvif = MAXVIFS;
         return c;
 }
 
 static struct mfc_cache *ipmr_cache_alloc_unres(void)
 {
         struct mfc_cache *c = kmem_cache_zalloc(mrt_cachep, GFP_ATOMIC);
-        if (c == NULL)
-                return NULL;
-        skb_queue_head_init(&c->mfc_un.unres.unresolved);
-        c->mfc_un.unres.expires = jiffies + 10*HZ;
+
+        if (c) {
+                skb_queue_head_init(&c->mfc_un.unres.unresolved);
+                c->mfc_un.unres.expires = jiffies + 10*HZ;
+        }
         return c;
 }
 
@@ -827,17 +840,15 @@ static void ipmr_cache_resolve(struct net *net, struct mr_table *mrt,
         struct sk_buff *skb;
         struct nlmsgerr *e;
 
-        /*
-         *      Play the pending entries through our router
-         */
+        /* Play the pending entries through our router */
 
         while ((skb = __skb_dequeue(&uc->mfc_un.unres.unresolved))) {
                 if (ip_hdr(skb)->version == 0) {
                         struct nlmsghdr *nlh = (struct nlmsghdr *)skb_pull(skb, sizeof(struct iphdr));
 
                         if (__ipmr_fill_mroute(mrt, skb, c, NLMSG_DATA(nlh)) > 0) {
-                                nlh->nlmsg_len = (skb_tail_pointer(skb) -
-                                                  (u8 *)nlh);
+                                nlh->nlmsg_len = skb_tail_pointer(skb) -
+                                                 (u8 *)nlh;
                         } else {
                                 nlh->nlmsg_type = NLMSG_ERROR;
                                 nlh->nlmsg_len = NLMSG_LENGTH(sizeof(struct nlmsgerr));
@@ -848,8 +859,9 @@ static void ipmr_cache_resolve(struct net *net, struct mr_table *mrt,
                         }
 
                         rtnl_unicast(skb, net, NETLINK_CB(skb).pid);
-                } else
+                } else {
                         ip_mr_forward(net, mrt, skb, c, 0);
+                }
         }
 }
 
@@ -867,6 +879,7 @@ static int ipmr_cache_report(struct mr_table *mrt,
         const int ihl = ip_hdrlen(pkt);
         struct igmphdr *igmp;
         struct igmpmsg *msg;
+        struct sock *mroute_sk;
         int ret;
 
 #ifdef CONFIG_IP_PIMSM
@@ -882,9 +895,9 @@ static int ipmr_cache_report(struct mr_table *mrt,
 #ifdef CONFIG_IP_PIMSM
         if (assert == IGMPMSG_WHOLEPKT) {
                 /* Ugly, but we have no choice with this interface.
-                   Duplicate old header, fix ihl, length etc.
-                   And all this only to mangle msg->im_msgtype and
-                   to set msg->im_mbz to "mbz" :-)
+                 * Duplicate old header, fix ihl, length etc.
+                 * And all this only to mangle msg->im_msgtype and
+                 * to set msg->im_mbz to "mbz" :-)
                  */
                 skb_push(skb, sizeof(struct iphdr));
                 skb_reset_network_header(skb);
@@ -901,39 +914,38 @@ static int ipmr_cache_report(struct mr_table *mrt,
 #endif
         {
 
-        /*
-         *      Copy the IP header
-         */
+        /* Copy the IP header */
 
         skb->network_header = skb->tail;
         skb_put(skb, ihl);
         skb_copy_to_linear_data(skb, pkt->data, ihl);
-        ip_hdr(skb)->protocol = 0;                      /* Flag to the kernel this is a route add */
+        ip_hdr(skb)->protocol = 0;      /* Flag to the kernel this is a route add */
         msg = (struct igmpmsg *)skb_network_header(skb);
         msg->im_vif = vifi;
         skb_dst_set(skb, dst_clone(skb_dst(pkt)));
 
-        /*
-         *      Add our header
-         */
+        /* Add our header */
 
-        igmp=(struct igmphdr *)skb_put(skb, sizeof(struct igmphdr));
+        igmp = (struct igmphdr *)skb_put(skb, sizeof(struct igmphdr));
         igmp->type      =
         msg->im_msgtype = assert;
-        igmp->code      =       0;
-        ip_hdr(skb)->tot_len = htons(skb->len);                 /* Fix the length */
+        igmp->code      = 0;
+        ip_hdr(skb)->tot_len = htons(skb->len);         /* Fix the length */
         skb->transport_header = skb->network_header;
         }
 
-        if (mrt->mroute_sk == NULL) {
+        rcu_read_lock();
+        mroute_sk = rcu_dereference(mrt->mroute_sk);
+        if (mroute_sk == NULL) {
+                rcu_read_unlock();
                 kfree_skb(skb);
                 return -EINVAL;
         }
 
-        /*
-         *      Deliver to mrouted
-         */
-        ret = sock_queue_rcv_skb(mrt->mroute_sk, skb);
+        /* Deliver to mrouted */
+
+        ret = sock_queue_rcv_skb(mroute_sk, skb);
+        rcu_read_unlock();
         if (ret < 0) {
                 if (net_ratelimit())
                         printk(KERN_WARNING "mroute: pending queue full, dropping entries.\n");
@@ -965,9 +977,7 @@ ipmr_cache_unresolved(struct mr_table *mrt, vifi_t vifi, struct sk_buff *skb)
         }
 
         if (!found) {
-                /*
-                 *      Create a new entry if allowable
-                 */
+                /* Create a new entry if allowable */
 
                 if (atomic_read(&mrt->cache_resolve_queue_len) >= 10 ||
                     (c = ipmr_cache_alloc_unres()) == NULL) {
@@ -977,16 +987,14 @@ ipmr_cache_unresolved(struct mr_table *mrt, vifi_t vifi, struct sk_buff *skb)
                         return -ENOBUFS;
                 }
 
-                /*
-                 *      Fill in the new cache entry
-                 */
+                /* Fill in the new cache entry */
+
                 c->mfc_parent   = -1;
                 c->mfc_origin   = iph->saddr;
                 c->mfc_mcastgrp = iph->daddr;
 
-                /*
-                 *      Reflect first query at mrouted.
-                 */
+                /* Reflect first query at mrouted. */
+
                 err = ipmr_cache_report(mrt, skb, vifi, IGMPMSG_NOCACHE);
                 if (err < 0) {
                         /* If the report failed throw the cache entry
@@ -1006,10 +1014,9 @@ ipmr_cache_unresolved(struct mr_table *mrt, vifi_t vifi, struct sk_buff *skb)
                         mod_timer(&mrt->ipmr_expire_timer, c->mfc_un.unres.expires);
         }
 
-        /*
-         *      See if we can append the packet
-         */
-        if (c->mfc_un.unres.unresolved.qlen>3) {
+        /* See if we can append the packet */
+
+        if (c->mfc_un.unres.unresolved.qlen > 3) {
                 kfree_skb(skb);
                 err = -ENOBUFS;
         } else {
@@ -1035,9 +1042,7 @@ static int ipmr_mfc_delete(struct mr_table *mrt, struct mfcctl *mfc)
         list_for_each_entry_safe(c, next, &mrt->mfc_cache_array[line], list) {
                 if (c->mfc_origin == mfc->mfcc_origin.s_addr &&
                     c->mfc_mcastgrp == mfc->mfcc_mcastgrp.s_addr) {
-                        write_lock_bh(&mrt_lock);
-                        list_del(&c->list);
-                        write_unlock_bh(&mrt_lock);
+                        list_del_rcu(&c->list);
 
                         ipmr_cache_free(c);
                         return 0;
@@ -1090,9 +1095,7 @@ static int ipmr_mfc_add(struct net *net, struct mr_table *mrt,
         if (!mrtsock)
                 c->mfc_flags |= MFC_STATIC;
 
-        write_lock_bh(&mrt_lock);
-        list_add(&c->list, &mrt->mfc_cache_array[line]);
-        write_unlock_bh(&mrt_lock);
+        list_add_rcu(&c->list, &mrt->mfc_cache_array[line]);
 
         /*
          *      Check to see if we resolved a queued list. If so we
@@ -1130,26 +1133,21 @@ static void mroute_clean_tables(struct mr_table *mrt)
         LIST_HEAD(list);
         struct mfc_cache *c, *next;
 
-        /*
-         *      Shut down all active vif entries
-         */
+        /* Shut down all active vif entries */
+
         for (i = 0; i < mrt->maxvif; i++) {
-                if (!(mrt->vif_table[i].flags&VIFF_STATIC))
+                if (!(mrt->vif_table[i].flags & VIFF_STATIC))
                         vif_delete(mrt, i, 0, &list);
         }
         unregister_netdevice_many(&list);
 
-        /*
-         *      Wipe the cache
-         */
+        /* Wipe the cache */
+
         for (i = 0; i < MFC_LINES; i++) {
                 list_for_each_entry_safe(c, next, &mrt->mfc_cache_array[i], list) {
-                        if (c->mfc_flags&MFC_STATIC)
+                        if (c->mfc_flags & MFC_STATIC)
                                 continue;
-                        write_lock_bh(&mrt_lock);
-                        list_del(&c->list);
-                        write_unlock_bh(&mrt_lock);
-
+                        list_del_rcu(&c->list);
                         ipmr_cache_free(c);
                 }
         }
@@ -1164,6 +1162,9 @@ static void mroute_clean_tables(struct mr_table *mrt)
         }
 }
 
+/* called from ip_ra_control(), before an RCU grace period,
+ * we dont need to call synchronize_rcu() here
+ */
 static void mrtsock_destruct(struct sock *sk)
 {
         struct net *net = sock_net(sk);
@@ -1171,13 +1172,9 @@ static void mrtsock_destruct(struct sock *sk)
 
         rtnl_lock();
         ipmr_for_each_table(mrt, net) {
-                if (sk == mrt->mroute_sk) {
+                if (sk == rtnl_dereference(mrt->mroute_sk)) {
                         IPV4_DEVCONF_ALL(net, MC_FORWARDING)--;
-
-                        write_lock_bh(&mrt_lock);
-                        mrt->mroute_sk = NULL;
-                        write_unlock_bh(&mrt_lock);
-
+                        rcu_assign_pointer(mrt->mroute_sk, NULL);
                         mroute_clean_tables(mrt);
                 }
         }
@@ -1204,7 +1201,8 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, unsi
                 return -ENOENT;
 
         if (optname != MRT_INIT) {
-                if (sk != mrt->mroute_sk && !capable(CAP_NET_ADMIN))
+                if (sk != rcu_dereference_raw(mrt->mroute_sk) &&
+                    !capable(CAP_NET_ADMIN))
                         return -EACCES;
         }
 
@@ -1217,23 +1215,20 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, unsi
                         return -ENOPROTOOPT;
 
                 rtnl_lock();
-                if (mrt->mroute_sk) {
+                if (rtnl_dereference(mrt->mroute_sk)) {
                         rtnl_unlock();
                         return -EADDRINUSE;
                 }
 
                 ret = ip_ra_control(sk, 1, mrtsock_destruct);
                 if (ret == 0) {
-                        write_lock_bh(&mrt_lock);
-                        mrt->mroute_sk = sk;
-                        write_unlock_bh(&mrt_lock);
-
+                        rcu_assign_pointer(mrt->mroute_sk, sk);
                         IPV4_DEVCONF_ALL(net, MC_FORWARDING)++;
                 }
                 rtnl_unlock();
                 return ret;
         case MRT_DONE:
-                if (sk != mrt->mroute_sk)
+                if (sk != rcu_dereference_raw(mrt->mroute_sk))
                         return -EACCES;
                 return ip_ra_control(sk, 0, NULL);
         case MRT_ADD_VIF:
@@ -1246,7 +1241,8 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, unsi
                         return -ENFILE;
                 rtnl_lock();
                 if (optname == MRT_ADD_VIF) {
-                        ret = vif_add(net, mrt, &vif, sk == mrt->mroute_sk);
+                        ret = vif_add(net, mrt, &vif,
+                                      sk == rtnl_dereference(mrt->mroute_sk));
                 } else {
                         ret = vif_delete(mrt, vif.vifc_vifi, 0, NULL);
                 }
@@ -1267,7 +1263,8 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, unsi
                 if (optname == MRT_DEL_MFC)
                         ret = ipmr_mfc_delete(mrt, &mfc);
                 else
-                        ret = ipmr_mfc_add(net, mrt, &mfc, sk == mrt->mroute_sk);
+                        ret = ipmr_mfc_add(net, mrt, &mfc,
+                                           sk == rtnl_dereference(mrt->mroute_sk));
                 rtnl_unlock();
                 return ret;
                 /*
@@ -1276,7 +1273,7 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, unsi
         case MRT_ASSERT:
         {
                 int v;
-                if (get_user(v,(int __user *)optval))
+                if (get_user(v, (int __user *)optval))
                         return -EFAULT;
                 mrt->mroute_do_assert = (v) ? 1 : 0;
                 return 0;
@@ -1286,7 +1283,7 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, unsi
         {
                 int v;
 
-                if (get_user(v,(int __user *)optval))
+                if (get_user(v, (int __user *)optval))
                         return -EFAULT;
                 v = (v) ? 1 : 0;
 
@@ -1309,14 +1306,16 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, unsi
                         return -EINVAL;
                 if (get_user(v, (u32 __user *)optval))
                         return -EFAULT;
-                if (sk == mrt->mroute_sk)
-                        return -EBUSY;
 
                 rtnl_lock();
                 ret = 0;
-                if (!ipmr_new_table(net, v))
-                        ret = -ENOMEM;
-                raw_sk(sk)->ipmr_table = v;
+                if (sk == rtnl_dereference(mrt->mroute_sk)) {
+                        ret = -EBUSY;
+                } else {
+                        if (!ipmr_new_table(net, v))
+                                ret = -ENOMEM;
+                        raw_sk(sk)->ipmr_table = v;
+                }
                 rtnl_unlock();
                 return ret;
         }
@@ -1347,9 +1346,9 @@ int ip_mroute_getsockopt(struct sock *sk, int optname, char __user *optval, int
 
         if (optname != MRT_VERSION &&
 #ifdef CONFIG_IP_PIMSM
-           optname!=MRT_PIM &&
+           optname != MRT_PIM &&
 #endif
-           optname!=MRT_ASSERT)
+           optname != MRT_ASSERT)
                 return -ENOPROTOOPT;
 
         if (get_user(olr, optlen))
@@ -1416,19 +1415,19 @@ int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg)
                 if (copy_from_user(&sr, arg, sizeof(sr)))
                         return -EFAULT;
 
-                read_lock(&mrt_lock);
+                rcu_read_lock();
                 c = ipmr_cache_find(mrt, sr.src.s_addr, sr.grp.s_addr);
                 if (c) {
                         sr.pktcnt = c->mfc_un.res.pkt;
                         sr.bytecnt = c->mfc_un.res.bytes;
                         sr.wrong_if = c->mfc_un.res.wrong_if;
-                        read_unlock(&mrt_lock);
+                        rcu_read_unlock();
 
                         if (copy_to_user(arg, &sr, sizeof(sr)))
                                 return -EFAULT;
                         return 0;
                 }
-                read_unlock(&mrt_lock);
+                rcu_read_unlock();
                 return -EADDRNOTAVAIL;
         default:
                 return -ENOIOCTLCMD;
@@ -1465,7 +1464,7 @@ static struct notifier_block ip_mr_notifier = {
 };
 
 /*
- *      Encapsulate a packet by attaching a valid IPIP header to it.
+ *      Encapsulate a packet by attaching a valid IPIP header to it.
  *      This avoids tunnel drivers and other mess and gives us the speed so
  *      important for multicast video.
  */
@@ -1480,7 +1479,7 @@ static void ip_encap(struct sk_buff *skb, __be32 saddr, __be32 daddr)
         skb_reset_network_header(skb);
         iph = ip_hdr(skb);
 
-        iph->version    =       4;
+        iph->version    =       4;
         iph->tos        =       old_iph->tos;
         iph->ttl        =       old_iph->ttl;
         iph->frag_off   =       0;
@@ -1498,7 +1497,7 @@ static void ip_encap(struct sk_buff *skb, __be32 saddr, __be32 daddr)
 
 static inline int ipmr_forward_finish(struct sk_buff *skb)
 {
-        struct ip_options * opt = &(IPCB(skb)->opt);
+        struct ip_options *opt = &(IPCB(skb)->opt);
 
         IP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), IPSTATS_MIB_OUTFORWDATAGRAMS);
 
@@ -1535,22 +1534,34 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
         }
 #endif
 
-        if (vif->flags&VIFF_TUNNEL) {
-                struct flowi fl = { .oif = vif->link,
-                                    .nl_u = { .ip4_u =
-                                              { .daddr = vif->remote,
-                                                .saddr = vif->local,
-                                                .tos = RT_TOS(iph->tos) } },
-                                    .proto = IPPROTO_IPIP };
+        if (vif->flags & VIFF_TUNNEL) {
+                struct flowi fl = {
+                        .oif = vif->link,
+                        .nl_u = {
+                                .ip4_u = {
+                                        .daddr = vif->remote,
+                                        .saddr = vif->local,
+                                        .tos = RT_TOS(iph->tos)
+                                }
+                        },
+                        .proto = IPPROTO_IPIP
+                };
+
                 if (ip_route_output_key(net, &rt, &fl))
                         goto out_free;
                 encap = sizeof(struct iphdr);
         } else {
-                struct flowi fl = { .oif = vif->link,
-                                    .nl_u = { .ip4_u =
-                                              { .daddr = iph->daddr,
-                                                .tos = RT_TOS(iph->tos) } },
-                                    .proto = IPPROTO_IPIP };
+                struct flowi fl = {
+                        .oif = vif->link,
+                        .nl_u = {
+                                .ip4_u = {
+                                        .daddr = iph->daddr,
+                                        .tos = RT_TOS(iph->tos)
+                                }
+                        },
+                        .proto = IPPROTO_IPIP
+                };
+
                 if (ip_route_output_key(net, &rt, &fl))
                         goto out_free;
         }
@@ -1559,8 +1570,8 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 
         if (skb->len+encap > dst_mtu(&rt->dst) && (ntohs(iph->frag_off) & IP_DF)) {
                 /* Do not fragment multicasts. Alas, IPv4 does not
-                   allow to send ICMP, so that packets will disappear
-                   to blackhole.
+                 * allow to send ICMP, so that packets will disappear
+                 * to blackhole.
                  */
 
                 IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
@@ -1583,7 +1594,8 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
         ip_decrease_ttl(ip_hdr(skb));
 
         /* FIXME: forward and output firewalls used to be called here.
-         * What do we do with netfilter? -- RR */
+         * What do we do with netfilter? -- RR
+         */
         if (vif->flags & VIFF_TUNNEL) {
                 ip_encap(skb, vif->local, vif->remote);
                 /* FIXME: extra output firewall step used to be here. --RR */
@@ -1644,15 +1656,15 @@ static int ip_mr_forward(struct net *net, struct mr_table *mrt,
 
                 if (skb_rtable(skb)->fl.iif == 0) {
                         /* It is our own packet, looped back.
-                           Very complicated situation...
-
-                           The best workaround until routing daemons will be
-                           fixed is not to redistribute packet, if it was
-                           send through wrong interface. It means, that
-                           multicast applications WILL NOT work for
-                           (S,G), which have default multicast route pointing
-                           to wrong oif. In any case, it is not a good
-                           idea to use multicasting applications on router.
+                         * Very complicated situation...
+                         *
+                         * The best workaround until routing daemons will be
+                         * fixed is not to redistribute packet, if it was
+                         * send through wrong interface. It means, that
+                         * multicast applications WILL NOT work for
+                         * (S,G), which have default multicast route pointing
+                         * to wrong oif. In any case, it is not a good
+                         * idea to use multicasting applications on router.
                          */
                         goto dont_forward;
                 }
@@ -1662,9 +1674,9 @@ static int ip_mr_forward(struct net *net, struct mr_table *mrt,
 
                 if (true_vifi >= 0 && mrt->mroute_do_assert &&
                     /* pimsm uses asserts, when switching from RPT to SPT,
-                       so that we cannot check that packet arrived on an oif.
-                       It is bad, but otherwise we would need to move pretty
-                       large chunk of pimd to kernel. Ough... --ANK
+                     * so that we cannot check that packet arrived on an oif.
+                     * It is bad, but otherwise we would need to move pretty
+                     * large chunk of pimd to kernel. Ough... --ANK
                      */
                     (mrt->mroute_do_pim ||
                      cache->mfc_un.res.ttls[true_vifi] < 255) &&
@@ -1682,10 +1694,12 @@ static int ip_mr_forward(struct net *net, struct mr_table *mrt,
         /*
          *      Forward the frame
          */
-        for (ct = cache->mfc_un.res.maxvif-1; ct >= cache->mfc_un.res.minvif; ct--) {
+        for (ct = cache->mfc_un.res.maxvif - 1;
+             ct >= cache->mfc_un.res.minvif; ct--) {
                 if (ip_hdr(skb)->ttl > cache->mfc_un.res.ttls[ct]) {
                         if (psend != -1) {
                                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
+
                                 if (skb2)
                                         ipmr_queue_xmit(net, mrt, skb2, cache,
                                                         psend);
@@ -1696,6 +1710,7 @@ static int ip_mr_forward(struct net *net, struct mr_table *mrt,
         if (psend != -1) {
                 if (local) {
                         struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
+
                         if (skb2)
                                 ipmr_queue_xmit(net, mrt, skb2, cache, psend);
                 } else {
@@ -1713,6 +1728,7 @@ dont_forward:
 
 /*
  *      Multicast packets for forwarding arrive here
+ *      Called with rcu_read_lock();
  */
 
 int ip_mr_input(struct sk_buff *skb)
@@ -1724,9 +1740,9 @@ int ip_mr_input(struct sk_buff *skb)
         int err;
 
         /* Packet is looped back after forward, it should not be
-           forwarded second time, but still can be delivered locally.
+         * forwarded second time, but still can be delivered locally.
          */
-        if (IPCB(skb)->flags&IPSKB_FORWARDED)
+        if (IPCB(skb)->flags & IPSKB_FORWARDED)
                 goto dont_forward;
 
         err = ipmr_fib_lookup(net, &skb_rtable(skb)->fl, &mrt);
@@ -1736,28 +1752,28 @@ int ip_mr_input(struct sk_buff *skb)
         }
 
         if (!local) {
-                    if (IPCB(skb)->opt.router_alert) {
-                            if (ip_call_ra_chain(skb))
-                                    return 0;
-                    } else if (ip_hdr(skb)->protocol == IPPROTO_IGMP){
-                            /* IGMPv1 (and broken IGMPv2 implementations sort of
-                               Cisco IOS <= 11.2(8)) do not put router alert
-                               option to IGMP packets destined to routable
-                               groups. It is very bad, because it means
-                               that we can forward NO IGMP messages.
-                             */
-                            read_lock(&mrt_lock);
-                            if (mrt->mroute_sk) {
-                                    nf_reset(skb);
-                                    raw_rcv(mrt->mroute_sk, skb);
-                                    read_unlock(&mrt_lock);
-                                    return 0;
-                            }
-                            read_unlock(&mrt_lock);
+                if (IPCB(skb)->opt.router_alert) {
+                        if (ip_call_ra_chain(skb))
+                                return 0;
+                } else if (ip_hdr(skb)->protocol == IPPROTO_IGMP) {
+                        /* IGMPv1 (and broken IGMPv2 implementations sort of
+                         * Cisco IOS <= 11.2(8)) do not put router alert
+                         * option to IGMP packets destined to routable
+                         * groups. It is very bad, because it means
+                         * that we can forward NO IGMP messages.
+                         */
+                        struct sock *mroute_sk;
+
+                        mroute_sk = rcu_dereference(mrt->mroute_sk);
+                        if (mroute_sk) {
+                                nf_reset(skb);
+                                raw_rcv(mroute_sk, skb);
+                                return 0;
+                        }
                     }
         }
 
-        read_lock(&mrt_lock);
+        /* already under rcu_read_lock() */
         cache = ipmr_cache_find(mrt, ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
 
         /*
@@ -1769,13 +1785,12 @@ int ip_mr_input(struct sk_buff *skb)
                 if (local) {
                         struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
                         ip_local_deliver(skb);
-                        if (skb2 == NULL) {
-                                read_unlock(&mrt_lock);
+                        if (skb2 == NULL)
                                 return -ENOBUFS;
-                        }
                         skb = skb2;
                 }
 
+                read_lock(&mrt_lock);
                 vif = ipmr_find_vif(mrt, skb->dev);
                 if (vif >= 0) {
                         int err2 = ipmr_cache_unresolved(mrt, vif, skb);
@@ -1788,8 +1803,8 @@ int ip_mr_input(struct sk_buff *skb)
                 return -ENODEV;
         }
 
+        read_lock(&mrt_lock);
         ip_mr_forward(net, mrt, skb, cache, local);
-
         read_unlock(&mrt_lock);
 
         if (local)
@@ -1805,6 +1820,7 @@ dont_forward:
 }
 
 #ifdef CONFIG_IP_PIMSM
+/* called with rcu_read_lock() */
 static int __pim_rcv(struct mr_table *mrt, struct sk_buff *skb,
                      unsigned int pimlen)
 {
@@ -1813,10 +1829,10 @@ static int __pim_rcv(struct mr_table *mrt, struct sk_buff *skb,
 
         encap = (struct iphdr *)(skb_transport_header(skb) + pimlen);
         /*
-           Check that:
-           a. packet is really destinted to a multicast group
-           b. packet is not a NULL-REGISTER
-           c. packet is not truncated
+         * Check that:
+         * a. packet is really sent to a multicast group
+         * b. packet is not a NULL-REGISTER
+         * c. packet is not truncated
          */
         if (!ipv4_is_multicast(encap->daddr) ||
             encap->tot_len == 0 ||
@@ -1826,26 +1842,23 @@ static int __pim_rcv(struct mr_table *mrt, struct sk_buff *skb,
         read_lock(&mrt_lock);
         if (mrt->mroute_reg_vif_num >= 0)
                 reg_dev = mrt->vif_table[mrt->mroute_reg_vif_num].dev;
-        if (reg_dev)
-                dev_hold(reg_dev);
         read_unlock(&mrt_lock);
 
         if (reg_dev == NULL)
                 return 1;
 
         skb->mac_header = skb->network_header;
-        skb_pull(skb, (u8*)encap - skb->data);
+        skb_pull(skb, (u8 *)encap - skb->data);
         skb_reset_network_header(skb);
         skb->protocol = htons(ETH_P_IP);
-        skb->ip_summed = 0;
+        skb->ip_summed = CHECKSUM_NONE;
         skb->pkt_type = PACKET_HOST;
 
         skb_tunnel_rx(skb, reg_dev);
 
         netif_rx(skb);
-        dev_put(reg_dev);
 
-        return 0;
+        return NET_RX_SUCCESS;
 }
 #endif
 
@@ -1854,7 +1867,7 @@ static int __pim_rcv(struct mr_table *mrt, struct sk_buff *skb,
  * Handle IGMP messages of PIMv1
  */
 
-int pim_rcv_v1(struct sk_buff * skb)
+int pim_rcv_v1(struct sk_buff *skb)
 {
         struct igmphdr *pim;
         struct net *net = dev_net(skb->dev);
@@ -1881,7 +1894,7 @@ drop:
 #endif
 
 #ifdef CONFIG_IP_PIMSM_V2
-static int pim_rcv(struct sk_buff * skb)
+static int pim_rcv(struct sk_buff *skb)
 {
         struct pimreghdr *pim;
         struct net *net = dev_net(skb->dev);
@@ -1891,8 +1904,8 @@ static int pim_rcv(struct sk_buff * skb)
                 goto drop;
 
         pim = (struct pimreghdr *)skb_transport_header(skb);
-        if (pim->type != ((PIM_VERSION<<4)|(PIM_REGISTER)) ||
-            (pim->flags&PIM_NULL_REGISTER) ||
+        if (pim->type != ((PIM_VERSION << 4) | (PIM_REGISTER)) ||
+            (pim->flags & PIM_NULL_REGISTER) ||
             (ip_compute_csum((void *)pim, sizeof(*pim)) != 0 &&
              csum_fold(skb_checksum(skb, 0, skb->len, 0))))
                 goto drop;
@@ -1958,28 +1971,33 @@ int ipmr_get_route(struct net *net,
         if (mrt == NULL)
                 return -ENOENT;
 
-        read_lock(&mrt_lock);
+        rcu_read_lock();
         cache = ipmr_cache_find(mrt, rt->rt_src, rt->rt_dst);
 
         if (cache == NULL) {
                 struct sk_buff *skb2;
                 struct iphdr *iph;
                 struct net_device *dev;
-                int vif;
+                int vif = -1;
 
                 if (nowait) {
-                        read_unlock(&mrt_lock);
+                        rcu_read_unlock();
                         return -EAGAIN;
                 }
 
                 dev = skb->dev;
-                if (dev == NULL || (vif = ipmr_find_vif(mrt, dev)) < 0) {
+                read_lock(&mrt_lock);
+                if (dev)
+                        vif = ipmr_find_vif(mrt, dev);
+                if (vif < 0) {
                         read_unlock(&mrt_lock);
+                        rcu_read_unlock();
                         return -ENODEV;
                 }
                 skb2 = skb_clone(skb, GFP_ATOMIC);
                 if (!skb2) {
                         read_unlock(&mrt_lock);
+                        rcu_read_unlock();
                         return -ENOMEM;
                 }
 
@@ -1992,13 +2010,16 @@ int ipmr_get_route(struct net *net,
                 iph->version = 0;
                 err = ipmr_cache_unresolved(mrt, vif, skb2);
                 read_unlock(&mrt_lock);
+                rcu_read_unlock();
                 return err;
         }
 
-        if (!nowait && (rtm->rtm_flags&RTM_F_NOTIFY))
+        read_lock(&mrt_lock);
+        if (!nowait && (rtm->rtm_flags & RTM_F_NOTIFY))
                 cache->mfc_flags |= MFC_NOTIFY;
         err = __ipmr_fill_mroute(mrt, skb, cache, rtm);
         read_unlock(&mrt_lock);
+        rcu_read_unlock();
         return err;
 }
 
@@ -2050,14 +2071,14 @@ static int ipmr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb)
         s_h = cb->args[1];
         s_e = cb->args[2];
 
-        read_lock(&mrt_lock);
+        rcu_read_lock();
         ipmr_for_each_table(mrt, net) {
                 if (t < s_t)
                         goto next_table;
                 if (t > s_t)
                         s_h = 0;
                 for (h = s_h; h < MFC_LINES; h++) {
-                        list_for_each_entry(mfc, &mrt->mfc_cache_array[h], list) {
+                        list_for_each_entry_rcu(mfc, &mrt->mfc_cache_array[h], list) {
                                 if (e < s_e)
                                         goto next_entry;
                                 if (ipmr_fill_mroute(mrt, skb,
@@ -2075,7 +2096,7 @@ next_table:
                 t++;
         }
 done:
-        read_unlock(&mrt_lock);
+        rcu_read_unlock();
 
         cb->args[2] = e;
         cb->args[1] = h;
@@ -2086,7 +2107,8 @@ done:
 
 #ifdef CONFIG_PROC_FS
 /*
- *      The /proc interfaces to multicast routing /proc/ip_mr_cache /proc/ip_mr_vif
+ *      The /proc interfaces to multicast routing :
+ *      /proc/net/ip_mr_cache & /proc/net/ip_mr_vif
  */
 struct ipmr_vif_iter {
         struct seq_net_private p;
@@ -2208,14 +2230,14 @@ static struct mfc_cache *ipmr_mfc_seq_idx(struct net *net,
         struct mr_table *mrt = it->mrt;
         struct mfc_cache *mfc;
 
-        read_lock(&mrt_lock);
+        rcu_read_lock();
         for (it->ct = 0; it->ct < MFC_LINES; it->ct++) {
                 it->cache = &mrt->mfc_cache_array[it->ct];
-                list_for_each_entry(mfc, it->cache, list)
+                list_for_each_entry_rcu(mfc, it->cache, list)
                         if (pos-- == 0)
                                 return mfc;
         }
-        read_unlock(&mrt_lock);
+        rcu_read_unlock();
 
         spin_lock_bh(&mfc_unres_lock);
         it->cache = &mrt->mfc_unres_queue;
@@ -2274,7 +2296,7 @@ static void *ipmr_mfc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
         }
 
         /* exhausted cache_array, show unresolved */
-        read_unlock(&mrt_lock);
+        rcu_read_unlock();
         it->cache = &mrt->mfc_unres_queue;
         it->ct = 0;
 
@@ -2282,7 +2304,7 @@ static void *ipmr_mfc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
         if (!list_empty(it->cache))
                 return list_first_entry(it->cache, struct mfc_cache, list);
 
- end_of_list:
+end_of_list:
         spin_unlock_bh(&mfc_unres_lock);
         it->cache = NULL;
 
@@ -2297,7 +2319,7 @@ static void ipmr_mfc_seq_stop(struct seq_file *seq, void *v)
         if (it->cache == &mrt->mfc_unres_queue)
                 spin_unlock_bh(&mfc_unres_lock);
         else if (it->cache == &mrt->mfc_cache_array[it->ct])
-                read_unlock(&mrt_lock);
+                rcu_read_unlock();
 }
 
 static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)
@@ -2323,7 +2345,7 @@ static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)
                                    mfc->mfc_un.res.bytes,
                                    mfc->mfc_un.res.wrong_if);
                         for (n = mfc->mfc_un.res.minvif;
-                             n < mfc->mfc_un.res.maxvif; n++ ) {
+                             n < mfc->mfc_un.res.maxvif; n++) {
                                 if (VIF_EXISTS(mrt, n) &&
                                     mfc->mfc_un.res.ttls[n] < 255)
                                         seq_printf(seq,
@@ -2421,7 +2443,7 @@ int __init ip_mr_init(void)
 
         mrt_cachep = kmem_cache_create("ip_mrt_cache",
                                        sizeof(struct mfc_cache),
-                                       0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
+                                       0, SLAB_HWCACHE_ALIGN | SLAB_PANIC,
                                        NULL);
         if (!mrt_cachep)
                 return -ENOMEM;