netfilter: xtables: compact table hook functions (1/2)
[safe/jmp/linux-2.6] / net / ipv6 / sit.c
index 510d31f..10207cc 100644 (file)
 #define HASH_SIZE  16
 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
 
-static void ipip6_fb_tunnel_init(struct net_device *dev);
 static void ipip6_tunnel_init(struct net_device *dev);
 static void ipip6_tunnel_setup(struct net_device *dev);
 
-static int sit_net_id;
+static int sit_net_id __read_mostly;
 struct sit_net {
        struct ip_tunnel *tunnels_r_l[HASH_SIZE];
        struct ip_tunnel *tunnels_r[HASH_SIZE];
@@ -77,8 +76,17 @@ struct sit_net {
        struct net_device *fb_tunnel_dev;
 };
 
-static DEFINE_RWLOCK(ipip6_lock);
+/*
+ * Locking : hash tables are protected by RCU and a spinlock
+ */
+static DEFINE_SPINLOCK(ipip6_lock);
+
+#define for_each_ip_tunnel_rcu(start) \
+       for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
 
+/*
+ * Must be invoked with rcu_read_lock
+ */
 static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
                struct net_device *dev, __be32 remote, __be32 local)
 {
@@ -87,26 +95,26 @@ static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
        struct ip_tunnel *t;
        struct sit_net *sitn = net_generic(net, sit_net_id);
 
-       for (t = sitn->tunnels_r_l[h0^h1]; t; t = t->next) {
+       for_each_ip_tunnel_rcu(sitn->tunnels_r_l[h0 ^ h1]) {
                if (local == t->parms.iph.saddr &&
                    remote == t->parms.iph.daddr &&
                    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
                    (t->dev->flags & IFF_UP))
                        return t;
        }
-       for (t = sitn->tunnels_r[h0]; t; t = t->next) {
+       for_each_ip_tunnel_rcu(sitn->tunnels_r[h0]) {
                if (remote == t->parms.iph.daddr &&
                    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
                    (t->dev->flags & IFF_UP))
                        return t;
        }
-       for (t = sitn->tunnels_l[h1]; t; t = t->next) {
+       for_each_ip_tunnel_rcu(sitn->tunnels_l[h1]) {
                if (local == t->parms.iph.saddr &&
                    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
                    (t->dev->flags & IFF_UP))
                        return t;
        }
-       t = sitn->tunnels_wc[0];
+       t = rcu_dereference(sitn->tunnels_wc[0]);
        if ((t != NULL) && (t->dev->flags & IFF_UP))
                return t;
        return NULL;
@@ -143,9 +151,9 @@ static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 
        for (tp = ipip6_bucket(sitn, t); *tp; tp = &(*tp)->next) {
                if (t == *tp) {
-                       write_lock_bh(&ipip6_lock);
+                       spin_lock_bh(&ipip6_lock);
                        *tp = t->next;
-                       write_unlock_bh(&ipip6_lock);
+                       spin_unlock_bh(&ipip6_lock);
                        break;
                }
        }
@@ -155,10 +163,10 @@ static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 {
        struct ip_tunnel **tp = ipip6_bucket(sitn, t);
 
+       spin_lock_bh(&ipip6_lock);
        t->next = *tp;
-       write_lock_bh(&ipip6_lock);
-       *tp = t;
-       write_unlock_bh(&ipip6_lock);
+       rcu_assign_pointer(*tp, t);
+       spin_unlock_bh(&ipip6_lock);
 }
 
 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
@@ -240,15 +248,22 @@ failed:
        return NULL;
 }
 
+static DEFINE_SPINLOCK(ipip6_prl_lock);
+
+#define for_each_prl_rcu(start)                        \
+       for (prl = rcu_dereference(start);      \
+            prl;                               \
+            prl = rcu_dereference(prl->next))
+
 static struct ip_tunnel_prl_entry *
 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 {
-       struct ip_tunnel_prl_entry *p = (struct ip_tunnel_prl_entry *)NULL;
+       struct ip_tunnel_prl_entry *prl;
 
-       for (p = t->prl; p; p = p->next)
-               if (p->addr == addr)
+       for_each_prl_rcu(t->prl)
+               if (prl->addr == addr)
                        break;
-       return p;
+       return prl;
 
 }
 
@@ -273,7 +288,7 @@ static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
                kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
                NULL;
 
-       read_lock(&ipip6_lock);
+       rcu_read_lock();
 
        ca = t->prl_count < cmax ? t->prl_count : cmax;
 
@@ -291,7 +306,7 @@ static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
        }
 
        c = 0;
-       for (prl = t->prl; prl; prl = prl->next) {
+       for_each_prl_rcu(t->prl) {
                if (c >= cmax)
                        break;
                if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
@@ -303,7 +318,7 @@ static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
                        break;
        }
 out:
-       read_unlock(&ipip6_lock);
+       rcu_read_unlock();
 
        len = sizeof(*kp) * c;
        ret = 0;
@@ -324,12 +339,14 @@ ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
        if (a->addr == htonl(INADDR_ANY))
                return -EINVAL;
 
-       write_lock(&ipip6_lock);
+       spin_lock(&ipip6_prl_lock);
 
        for (p = t->prl; p; p = p->next) {
                if (p->addr == a->addr) {
-                       if (chg)
-                               goto update;
+                       if (chg) {
+                               p->flags = a->flags;
+                               goto out;
+                       }
                        err = -EEXIST;
                        goto out;
                }
@@ -346,46 +363,63 @@ ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
                goto out;
        }
 
+       INIT_RCU_HEAD(&p->rcu_head);
        p->next = t->prl;
-       t->prl = p;
-       t->prl_count++;
-update:
        p->addr = a->addr;
        p->flags = a->flags;
+       t->prl_count++;
+       rcu_assign_pointer(t->prl, p);
 out:
-       write_unlock(&ipip6_lock);
+       spin_unlock(&ipip6_prl_lock);
        return err;
 }
 
+static void prl_entry_destroy_rcu(struct rcu_head *head)
+{
+       kfree(container_of(head, struct ip_tunnel_prl_entry, rcu_head));
+}
+
+static void prl_list_destroy_rcu(struct rcu_head *head)
+{
+       struct ip_tunnel_prl_entry *p, *n;
+
+       p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
+       do {
+               n = p->next;
+               kfree(p);
+               p = n;
+       } while (p);
+}
+
 static int
 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 {
        struct ip_tunnel_prl_entry *x, **p;
        int err = 0;
 
-       write_lock(&ipip6_lock);
+       spin_lock(&ipip6_prl_lock);
 
        if (a && a->addr != htonl(INADDR_ANY)) {
                for (p = &t->prl; *p; p = &(*p)->next) {
                        if ((*p)->addr == a->addr) {
                                x = *p;
                                *p = x->next;
-                               kfree(x);
+                               call_rcu(&x->rcu_head, prl_entry_destroy_rcu);
                                t->prl_count--;
                                goto out;
                        }
                }
                err = -ENXIO;
        } else {
-               while (t->prl) {
+               if (t->prl) {
+                       t->prl_count = 0;
                        x = t->prl;
-                       t->prl = t->prl->next;
-                       kfree(x);
-                       t->prl_count--;
+                       call_rcu(&x->rcu_head, prl_list_destroy_rcu);
+                       t->prl = NULL;
                }
        }
 out:
-       write_unlock(&ipip6_lock);
+       spin_unlock(&ipip6_prl_lock);
        return err;
 }
 
@@ -395,7 +429,7 @@ isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
        struct ip_tunnel_prl_entry *p;
        int ok = 1;
 
-       read_lock(&ipip6_lock);
+       rcu_read_lock();
        p = __ipip6_tunnel_locate_prl(t, iph->saddr);
        if (p) {
                if (p->flags & PRL_DEFAULT)
@@ -411,7 +445,7 @@ isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
                else
                        ok = 0;
        }
-       read_unlock(&ipip6_lock);
+       rcu_read_unlock();
        return ok;
 }
 
@@ -421,9 +455,9 @@ static void ipip6_tunnel_uninit(struct net_device *dev)
        struct sit_net *sitn = net_generic(net, sit_net_id);
 
        if (dev == sitn->fb_tunnel_dev) {
-               write_lock_bh(&ipip6_lock);
+               spin_lock_bh(&ipip6_lock);
                sitn->tunnels_wc[0] = NULL;
-               write_unlock_bh(&ipip6_lock);
+               spin_unlock_bh(&ipip6_lock);
                dev_put(dev);
        } else {
                ipip6_tunnel_unlink(sitn, netdev_priv(dev));
@@ -476,7 +510,7 @@ static int ipip6_err(struct sk_buff *skb, u32 info)
 
        err = -ENOENT;
 
-       read_lock(&ipip6_lock);
+       rcu_read_lock();
        t = ipip6_tunnel_lookup(dev_net(skb->dev),
                                skb->dev,
                                iph->daddr,
@@ -494,7 +528,7 @@ static int ipip6_err(struct sk_buff *skb, u32 info)
                t->err_count = 1;
        t->err_time = jiffies;
 out:
-       read_unlock(&ipip6_lock);
+       rcu_read_unlock();
        return err;
 }
 
@@ -514,7 +548,7 @@ static int ipip6_rcv(struct sk_buff *skb)
 
        iph = ip_hdr(skb);
 
-       read_lock(&ipip6_lock);
+       rcu_read_lock();
        tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
                                     iph->saddr, iph->daddr);
        if (tunnel != NULL) {
@@ -528,7 +562,7 @@ static int ipip6_rcv(struct sk_buff *skb)
                if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
                    !isatap_chksrc(skb, iph, tunnel)) {
                        tunnel->dev->stats.rx_errors++;
-                       read_unlock(&ipip6_lock);
+                       rcu_read_unlock();
                        kfree_skb(skb);
                        return 0;
                }
@@ -539,12 +573,12 @@ static int ipip6_rcv(struct sk_buff *skb)
                nf_reset(skb);
                ipip6_ecn_decapsulate(iph, skb);
                netif_rx(skb);
-               read_unlock(&ipip6_lock);
+               rcu_read_unlock();
                return 0;
        }
 
        icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
-       read_unlock(&ipip6_lock);
+       rcu_read_unlock();
 out:
        kfree_skb(skb);
        return 0;
@@ -602,6 +636,7 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
        struct iphdr  *tiph = &tunnel->parms.iph;
        struct ipv6hdr *iph6 = ipv6_hdr(skb);
        u8     tos = tunnel->parms.iph.tos;
+       __be16 df = tiph->frag_off;
        struct rtable *rt;                      /* Route to the other host */
        struct net_device *tdev;                        /* Device to other host */
        struct iphdr  *iph;                     /* Our new IP header */
@@ -691,25 +726,28 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
                goto tx_error;
        }
 
-       if (tiph->frag_off)
+       if (df) {
                mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
-       else
-               mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
 
-       if (mtu < 68) {
-               stats->collisions++;
-               ip_rt_put(rt);
-               goto tx_error;
-       }
-       if (mtu < IPV6_MIN_MTU)
-               mtu = IPV6_MIN_MTU;
-       if (tunnel->parms.iph.daddr && skb_dst(skb))
-               skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
+               if (mtu < 68) {
+                       stats->collisions++;
+                       ip_rt_put(rt);
+                       goto tx_error;
+               }
 
-       if (skb->len > mtu) {
-               icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
-               ip_rt_put(rt);
-               goto tx_error;
+               if (mtu < IPV6_MIN_MTU) {
+                       mtu = IPV6_MIN_MTU;
+                       df = 0;
+               }
+
+               if (tunnel->parms.iph.daddr && skb_dst(skb))
+                       skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
+
+               if (skb->len > mtu) {
+                       icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
+                       ip_rt_put(rt);
+                       goto tx_error;
+               }
        }
 
        if (tunnel->err_count > 0) {
@@ -757,11 +795,7 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
        iph                     =       ip_hdr(skb);
        iph->version            =       4;
        iph->ihl                =       sizeof(struct iphdr)>>2;
-       if (mtu > IPV6_MIN_MTU)
-               iph->frag_off   =       tiph->frag_off;
-       else
-               iph->frag_off   =       0;
-
+       iph->frag_off           =       df;
        iph->protocol           =       IPPROTO_IPV6;
        iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
        iph->daddr              =       rt->rt_dst;
@@ -1085,7 +1119,7 @@ static void ipip6_tunnel_init(struct net_device *dev)
        ipip6_tunnel_bind_dev(dev);
 }
 
-static void ipip6_fb_tunnel_init(struct net_device *dev)
+static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
 {
        struct ip_tunnel *tunnel = netdev_priv(dev);
        struct iphdr *iph = &tunnel->parms.iph;
@@ -1110,33 +1144,27 @@ static struct xfrm_tunnel sit_handler = {
        .priority       =       1,
 };
 
-static void sit_destroy_tunnels(struct sit_net *sitn)
+static void __net_exit sit_destroy_tunnels(struct sit_net *sitn, struct list_head *head)
 {
        int prio;
 
        for (prio = 1; prio < 4; prio++) {
                int h;
                for (h = 0; h < HASH_SIZE; h++) {
-                       struct ip_tunnel *t;
-                       while ((t = sitn->tunnels[prio][h]) != NULL)
-                               unregister_netdevice(t->dev);
+                       struct ip_tunnel *t = sitn->tunnels[prio][h];
+
+                       while (t != NULL) {
+                               unregister_netdevice_queue(t->dev, head);
+                               t = t->next;
+                       }
                }
        }
 }
 
-static int sit_init_net(struct net *net)
+static int __net_init sit_init_net(struct net *net)
 {
+       struct sit_net *sitn = net_generic(net, sit_net_id);
        int err;
-       struct sit_net *sitn;
-
-       err = -ENOMEM;
-       sitn = kzalloc(sizeof(struct sit_net), GFP_KERNEL);
-       if (sitn == NULL)
-               goto err_alloc;
-
-       err = net_assign_generic(net, sit_net_id, sitn);
-       if (err < 0)
-               goto err_assign;
 
        sitn->tunnels[0] = sitn->tunnels_wc;
        sitn->tunnels[1] = sitn->tunnels_l;
@@ -1163,35 +1191,34 @@ err_reg_dev:
        dev_put(sitn->fb_tunnel_dev);
        free_netdev(sitn->fb_tunnel_dev);
 err_alloc_dev:
-       /* nothing */
-err_assign:
-       kfree(sitn);
-err_alloc:
        return err;
 }
 
-static void sit_exit_net(struct net *net)
+static void __net_exit sit_exit_net(struct net *net)
 {
-       struct sit_net *sitn;
+       struct sit_net *sitn = net_generic(net, sit_net_id);
+       LIST_HEAD(list);
 
-       sitn = net_generic(net, sit_net_id);
        rtnl_lock();
-       sit_destroy_tunnels(sitn);
-       unregister_netdevice(sitn->fb_tunnel_dev);
+       sit_destroy_tunnels(sitn, &list);
+       unregister_netdevice_queue(sitn->fb_tunnel_dev, &list);
+       unregister_netdevice_many(&list);
        rtnl_unlock();
-       kfree(sitn);
 }
 
 static struct pernet_operations sit_net_ops = {
        .init = sit_init_net,
        .exit = sit_exit_net,
+       .id   = &sit_net_id,
+       .size = sizeof(struct sit_net),
 };
 
 static void __exit sit_cleanup(void)
 {
        xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
 
-       unregister_pernet_gen_device(sit_net_id, &sit_net_ops);
+       unregister_pernet_device(&sit_net_ops);
+       rcu_barrier(); /* Wait for completion of call_rcu()'s */
 }
 
 static int __init sit_init(void)
@@ -1205,7 +1232,7 @@ static int __init sit_init(void)
                return -EAGAIN;
        }
 
-       err = register_pernet_gen_device(&sit_net_id, &sit_net_ops);
+       err = register_pernet_device(&sit_net_ops);
        if (err < 0)
                xfrm4_tunnel_deregister(&sit_handler, AF_INET6);