1 files changed, 103 insertions, 89 deletions

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 7d02a9f999fa..36e27c2107de 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -147,35 +147,43 @@ static void fib_flush(struct net *net)
                 rt_cache_flush(net, -1);
 }
 
-/*
- *      Find the first device with a given source address.
+/**
+ * __ip_dev_find - find the first device with a given source address.
+ * @net: the net namespace
+ * @addr: the source address
+ * @devref: if true, take a reference on the found device
+ *
+ * If a caller uses devref=false, it should be protected by RCU, or RTNL
  */
-
-struct net_device * ip_dev_find(struct net *net, __be32 addr)
+struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref)
 {
-        struct flowi fl = { .nl_u = { .ip4_u = { .daddr = addr } } };
-        struct fib_result res;
+        struct flowi fl = {
+                .nl_u = {
+                        .ip4_u = {
+                                .daddr = addr
+                        }
+                },
+                .flags = FLOWI_FLAG_MATCH_ANY_IIF
+        };
+        struct fib_result res = { 0 };
         struct net_device *dev = NULL;
-        struct fib_table *local_table;
 
-#ifdef CONFIG_IP_MULTIPLE_TABLES
-        res.r = NULL;
-#endif
-
-        local_table = fib_get_table(net, RT_TABLE_LOCAL);
-        if (!local_table || fib_table_lookup(local_table, &fl, &res))
+        rcu_read_lock();
+        if (fib_lookup(net, &fl, &res)) {
+                rcu_read_unlock();
                 return NULL;
+        }
         if (res.type != RTN_LOCAL)
                 goto out;
         dev = FIB_RES_DEV(res);
 
-        if (dev)
+        if (dev && devref)
                 dev_hold(dev);
 out:
-        fib_res_put(&res);
+        rcu_read_unlock();
         return dev;
 }
-EXPORT_SYMBOL(ip_dev_find);
+EXPORT_SYMBOL(__ip_dev_find);
 
 /*
  * Find address type as if only "dev" was present in the system. If
@@ -202,11 +210,12 @@ static inline unsigned __inet_dev_addr_type(struct net *net,
         local_table = fib_get_table(net, RT_TABLE_LOCAL);
         if (local_table) {
                 ret = RTN_UNICAST;
-                if (!fib_table_lookup(local_table, &fl, &res)) {
+                rcu_read_lock();
+                if (!fib_table_lookup(local_table, &fl, &res, FIB_LOOKUP_NOREF)) {
                         if (!dev || dev == res.fi->fib_dev)
                                 ret = res.type;
-                        fib_res_put(&res);
                 }
+                rcu_read_unlock();
         }
         return ret;
 }
@@ -220,30 +229,34 @@ EXPORT_SYMBOL(inet_addr_type);
 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
                                 __be32 addr)
 {
-       return __inet_dev_addr_type(net, dev, addr);
+        return __inet_dev_addr_type(net, dev, addr);
 }
 EXPORT_SYMBOL(inet_dev_addr_type);
 
 /* Given (packet source, input interface) and optional (dst, oif, tos):
-   - (main) check, that source is valid i.e. not broadcast or our local
-     address.
-   - figure out what "logical" interface this packet arrived
-     and calculate "specific destination" address.
-   - check, that packet arrived from expected physical interface.
+ * - (main) check, that source is valid i.e. not broadcast or our local
+ *   address.
+ * - figure out what "logical" interface this packet arrived
+ *   and calculate "specific destination" address.
+ * - check, that packet arrived from expected physical interface.
+ * called with rcu_read_lock()
  */
-
 int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
                         struct net_device *dev, __be32 *spec_dst,
                         u32 *itag, u32 mark)
 {
         struct in_device *in_dev;
-        struct flowi fl = { .nl_u = { .ip4_u =
-                                      { .daddr = src,
-                                        .saddr = dst,
-                                        .tos = tos } },
-                            .mark = mark,
-                            .iif = oif };
-
+        struct flowi fl = {
+                .nl_u = {
+                        .ip4_u = {
+                                .daddr = src,
+                                .saddr = dst,
+                                .tos = tos
+                        }
+                },
+                .mark = mark,
+                .iif = oif
+        };
         struct fib_result res;
         int no_addr, rpf, accept_local;
         bool dev_match;
@@ -251,7 +264,6 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
         struct net *net;
 
         no_addr = rpf = accept_local = 0;
-        rcu_read_lock();
         in_dev = __in_dev_get_rcu(dev);
         if (in_dev) {
                 no_addr = in_dev->ifa_list == NULL;
@@ -260,7 +272,6 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
                 if (mark && !IN_DEV_SRC_VMARK(in_dev))
                         fl.mark = 0;
         }
-        rcu_read_unlock();
 
         if (in_dev == NULL)
                 goto e_inval;
@@ -270,7 +281,7 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
                 goto last_resort;
         if (res.type != RTN_UNICAST) {
                 if (res.type != RTN_LOCAL || !accept_local)
-                        goto e_inval_res;
+                        goto e_inval;
         }
         *spec_dst = FIB_RES_PREFSRC(res);
         fib_combine_itag(itag, &res);
@@ -291,10 +302,8 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
 #endif
         if (dev_match) {
                 ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
-                fib_res_put(&res);
                 return ret;
         }
-        fib_res_put(&res);
         if (no_addr)
                 goto last_resort;
         if (rpf == 1)
@@ -307,7 +316,6 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
                         *spec_dst = FIB_RES_PREFSRC(res);
                         ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
                 }
-                fib_res_put(&res);
         }
         return ret;
 
@@ -318,8 +326,6 @@ last_resort:
         *itag = 0;
         return 0;
 
-e_inval_res:
-        fib_res_put(&res);
 e_inval:
         return -EINVAL;
 e_rpf:
@@ -472,9 +478,9 @@ static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
 }
 
 /*
- *      Handle IP routing ioctl calls. These are used to manipulate the routing tables
+ * Handle IP routing ioctl calls.
+ * These are used to manipulate the routing tables
  */
-
 int ip_rt_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 {
         struct fib_config cfg;
@@ -518,7 +524,7 @@ int ip_rt_ioctl(struct net *net, unsigned int cmd, void __user *arg)
         return -EINVAL;
 }
 
-const struct nla_policy rtm_ipv4_policy[RTA_MAX+1] = {
+const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
         [RTA_DST]               = { .type = NLA_U32 },
         [RTA_SRC]               = { .type = NLA_U32 },
         [RTA_IIF]               = { .type = NLA_U32 },
@@ -532,7 +538,7 @@ const struct nla_policy rtm_ipv4_policy[RTA_MAX+1] = {
 };
 
 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
-                            struct nlmsghdr *nlh, struct fib_config *cfg)
+                             struct nlmsghdr *nlh, struct fib_config *cfg)
 {
         struct nlattr *attr;
         int err, remaining;
@@ -687,12 +693,11 @@ out:
 }
 
 /* Prepare and feed intra-kernel routing request.
-   Really, it should be netlink message, but :-( netlink
-   can be not configured, so that we feed it directly
-   to fib engine. It is legal, because all events occur
-   only when netlink is already locked.
+ * Really, it should be netlink message, but :-( netlink
+ * can be not configured, so that we feed it directly
+ * to fib engine. It is legal, because all events occur
+ * only when netlink is already locked.
  */
-
 static void fib_magic(int cmd, int type, __be32 dst, int dst_len, struct in_ifaddr *ifa)
 {
         struct net *net = dev_net(ifa->ifa_dev->dev);
@@ -738,9 +743,9 @@ void fib_add_ifaddr(struct in_ifaddr *ifa)
         struct in_ifaddr *prim = ifa;
         __be32 mask = ifa->ifa_mask;
         __be32 addr = ifa->ifa_local;
-        __be32 prefix = ifa->ifa_address&mask;
+        __be32 prefix = ifa->ifa_address & mask;
 
-        if (ifa->ifa_flags&IFA_F_SECONDARY) {
+        if (ifa->ifa_flags & IFA_F_SECONDARY) {
                 prim = inet_ifa_byprefix(in_dev, prefix, mask);
                 if (prim == NULL) {
                         printk(KERN_WARNING "fib_add_ifaddr: bug: prim == NULL\n");
@@ -750,22 +755,24 @@ void fib_add_ifaddr(struct in_ifaddr *ifa)
 
         fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim);
 
-        if (!(dev->flags&IFF_UP))
+        if (!(dev->flags & IFF_UP))
                 return;
 
         /* Add broadcast address, if it is explicitly assigned. */
         if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF))
                 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
 
-        if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags&IFA_F_SECONDARY) &&
+        if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
             (prefix != addr || ifa->ifa_prefixlen < 32)) {
-                fib_magic(RTM_NEWROUTE, dev->flags&IFF_LOOPBACK ? RTN_LOCAL :
-                          RTN_UNICAST, prefix, ifa->ifa_prefixlen, prim);
+                fib_magic(RTM_NEWROUTE,
+                          dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
+                          prefix, ifa->ifa_prefixlen, prim);
 
                 /* Add network specific broadcasts, when it takes a sense */
                 if (ifa->ifa_prefixlen < 31) {
                         fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32, prim);
-                        fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix|~mask, 32, prim);
+                        fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
+                                  32, prim);
                 }
         }
 }
@@ -776,17 +783,18 @@ static void fib_del_ifaddr(struct in_ifaddr *ifa)
         struct net_device *dev = in_dev->dev;
         struct in_ifaddr *ifa1;
         struct in_ifaddr *prim = ifa;
-        __be32 brd = ifa->ifa_address|~ifa->ifa_mask;
-        __be32 any = ifa->ifa_address&ifa->ifa_mask;
+        __be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
+        __be32 any = ifa->ifa_address & ifa->ifa_mask;
 #define LOCAL_OK        1
 #define BRD_OK          2
 #define BRD0_OK         4
 #define BRD1_OK         8
         unsigned ok = 0;
 
-        if (!(ifa->ifa_flags&IFA_F_SECONDARY))
-                fib_magic(RTM_DELROUTE, dev->flags&IFF_LOOPBACK ? RTN_LOCAL :
-                          RTN_UNICAST, any, ifa->ifa_prefixlen, prim);
+        if (!(ifa->ifa_flags & IFA_F_SECONDARY))
+                fib_magic(RTM_DELROUTE,
+                          dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
+                          any, ifa->ifa_prefixlen, prim);
         else {
                 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
                 if (prim == NULL) {
@@ -796,9 +804,9 @@ static void fib_del_ifaddr(struct in_ifaddr *ifa)
         }
 
         /* Deletion is more complicated than add.
-           We should take care of not to delete too much :-)
-
-           Scan address list to be sure that addresses are really gone.
+         * We should take care of not to delete too much :-)
+         *
+         * Scan address list to be sure that addresses are really gone.
          */
 
         for (ifa1 = in_dev->ifa_list; ifa1; ifa1 = ifa1->ifa_next) {
@@ -812,23 +820,23 @@ static void fib_del_ifaddr(struct in_ifaddr *ifa)
                         ok |= BRD0_OK;
         }
 
-        if (!(ok&BRD_OK))
+        if (!(ok & BRD_OK))
                 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
-        if (!(ok&BRD1_OK))
+        if (!(ok & BRD1_OK))
                 fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32, prim);
-        if (!(ok&BRD0_OK))
+        if (!(ok & BRD0_OK))
                 fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32, prim);
-        if (!(ok&LOCAL_OK)) {
+        if (!(ok & LOCAL_OK)) {
                 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim);
 
                 /* Check, that this local address finally disappeared. */
                 if (inet_addr_type(dev_net(dev), ifa->ifa_local) != RTN_LOCAL) {
                         /* And the last, but not the least thing.
-                           We must flush stray FIB entries.
-
-                           First of all, we scan fib_info list searching
-                           for stray nexthop entries, then ignite fib_flush.
-                        */
+                         * We must flush stray FIB entries.
+                         *
+                         * First of all, we scan fib_info list searching
+                         * for stray nexthop entries, then ignite fib_flush.
+                         */
                         if (fib_sync_down_addr(dev_net(dev), ifa->ifa_local))
                                 fib_flush(dev_net(dev));
                 }
@@ -839,14 +847,20 @@ static void fib_del_ifaddr(struct in_ifaddr *ifa)
 #undef BRD1_OK
 }
 
-static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb )
+static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb)
 {
 
         struct fib_result       res;
-        struct flowi            fl = { .mark = frn->fl_mark,
-                                       .nl_u = { .ip4_u = { .daddr = frn->fl_addr,
-                                                            .tos = frn->fl_tos,
-                                                            .scope = frn->fl_scope } } };
+        struct flowi            fl = {
+                .mark = frn->fl_mark,
+                .nl_u = {
+                        .ip4_u = {
+                                .daddr = frn->fl_addr,
+                                .tos = frn->fl_tos,
+                                .scope = frn->fl_scope
+                        }
+                }
+        };
 
 #ifdef CONFIG_IP_MULTIPLE_TABLES
         res.r = NULL;
@@ -857,15 +871,16 @@ static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb )
                 local_bh_disable();
 
                 frn->tb_id = tb->tb_id;
-                frn->err = fib_table_lookup(tb, &fl, &res);
+                rcu_read_lock();
+                frn->err = fib_table_lookup(tb, &fl, &res, FIB_LOOKUP_NOREF);
 
                 if (!frn->err) {
                         frn->prefixlen = res.prefixlen;
                         frn->nh_sel = res.nh_sel;
                         frn->type = res.type;
                         frn->scope = res.scope;
-                        fib_res_put(&res);
                 }
+                rcu_read_unlock();
                 local_bh_enable();
         }
 }
@@ -894,8 +909,8 @@ static void nl_fib_input(struct sk_buff *skb)
 
         nl_fib_lookup(frn, tb);
 
-        pid = NETLINK_CB(skb).pid;       /* pid of sending process */
-        NETLINK_CB(skb).pid = 0;         /* from kernel */
+        pid = NETLINK_CB(skb).pid;      /* pid of sending process */
+        NETLINK_CB(skb).pid = 0;        /* from kernel */
         NETLINK_CB(skb).dst_group = 0;  /* unicast */
         netlink_unicast(net->ipv4.fibnl, skb, pid, MSG_DONTWAIT);
 }
@@ -942,7 +957,7 @@ static int fib_inetaddr_event(struct notifier_block *this, unsigned long event,
                 fib_del_ifaddr(ifa);
                 if (ifa->ifa_dev->ifa_list == NULL) {
                         /* Last address was deleted from this interface.
-                           Disable IP.
+                         * Disable IP.
                          */
                         fib_disable_ip(dev, 1, 0);
                 } else {
@@ -1001,16 +1016,15 @@ static struct notifier_block fib_netdev_notifier = {
 static int __net_init ip_fib_net_init(struct net *net)
 {
         int err;
-        unsigned int i;
+        size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
 
-        net->ipv4.fib_table_hash = kzalloc(
-                        sizeof(struct hlist_head)*FIB_TABLE_HASHSZ, GFP_KERNEL);
+        /* Avoid false sharing : Use at least a full cache line */
+        size = max_t(size_t, size, L1_CACHE_BYTES);
+
+        net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
         if (net->ipv4.fib_table_hash == NULL)
                 return -ENOMEM;
 
-        for (i = 0; i < FIB_TABLE_HASHSZ; i++)
-                INIT_HLIST_HEAD(&net->ipv4.fib_table_hash[i]);
-
         err = fib4_rules_init(net);
         if (err < 0)
                 goto fail;