ipmr: RCU conversion of mroute_sk
Use RCU and RTNL to protect (struct mr_table)->mroute_sk Readers use RCU, writers use RTNL. ip_ra_control() already use an RCU grace period before ip_ra_destroy_rcu(), so we dont need synchronize_rcu() in mrtsock_destruct() Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
David S. Miller
Родитель
55747a0a73
Коммит
4c9687098f
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@ -75,7 +75,7 @@ struct mr_table {
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struct net *net;
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#endif
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u32 id;
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struct sock *mroute_sk;
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struct sock __rcu *mroute_sk;
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struct timer_list ipmr_expire_timer;
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struct list_head mfc_unres_queue;
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struct list_head mfc_cache_array[MFC_LINES];
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@ -867,6 +867,7 @@ static int ipmr_cache_report(struct mr_table *mrt,
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const int ihl = ip_hdrlen(pkt);
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struct igmphdr *igmp;
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struct igmpmsg *msg;
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struct sock *mroute_sk;
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int ret;
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#ifdef CONFIG_IP_PIMSM
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@ -925,7 +926,10 @@ static int ipmr_cache_report(struct mr_table *mrt,
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skb->transport_header = skb->network_header;
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}
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if (mrt->mroute_sk == NULL) {
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rcu_read_lock();
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mroute_sk = rcu_dereference(mrt->mroute_sk);
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if (mroute_sk == NULL) {
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rcu_read_unlock();
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kfree_skb(skb);
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return -EINVAL;
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}
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@ -933,7 +937,8 @@ static int ipmr_cache_report(struct mr_table *mrt,
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/*
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* Deliver to mrouted
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*/
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ret = sock_queue_rcv_skb(mrt->mroute_sk, skb);
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ret = sock_queue_rcv_skb(mroute_sk, skb);
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rcu_read_unlock();
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if (ret < 0) {
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if (net_ratelimit())
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printk(KERN_WARNING "mroute: pending queue full, dropping entries.\n");
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@ -1164,6 +1169,9 @@ static void mroute_clean_tables(struct mr_table *mrt)
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}
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}
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/* called from ip_ra_control(), before an RCU grace period,
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* we dont need to call synchronize_rcu() here
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*/
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static void mrtsock_destruct(struct sock *sk)
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{
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struct net *net = sock_net(sk);
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@ -1171,13 +1179,9 @@ static void mrtsock_destruct(struct sock *sk)
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rtnl_lock();
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ipmr_for_each_table(mrt, net) {
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if (sk == mrt->mroute_sk) {
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if (sk == rtnl_dereference(mrt->mroute_sk)) {
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IPV4_DEVCONF_ALL(net, MC_FORWARDING)--;
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write_lock_bh(&mrt_lock);
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mrt->mroute_sk = NULL;
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write_unlock_bh(&mrt_lock);
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rcu_assign_pointer(mrt->mroute_sk, NULL);
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mroute_clean_tables(mrt);
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}
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}
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@ -1204,7 +1208,8 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, unsi
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return -ENOENT;
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if (optname != MRT_INIT) {
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if (sk != mrt->mroute_sk && !capable(CAP_NET_ADMIN))
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if (sk != rcu_dereference_raw(mrt->mroute_sk) &&
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!capable(CAP_NET_ADMIN))
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return -EACCES;
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}
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@ -1217,23 +1222,20 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, unsi
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return -ENOPROTOOPT;
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rtnl_lock();
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if (mrt->mroute_sk) {
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if (rtnl_dereference(mrt->mroute_sk)) {
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rtnl_unlock();
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return -EADDRINUSE;
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}
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ret = ip_ra_control(sk, 1, mrtsock_destruct);
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if (ret == 0) {
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write_lock_bh(&mrt_lock);
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mrt->mroute_sk = sk;
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write_unlock_bh(&mrt_lock);
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rcu_assign_pointer(mrt->mroute_sk, sk);
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IPV4_DEVCONF_ALL(net, MC_FORWARDING)++;
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}
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rtnl_unlock();
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return ret;
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case MRT_DONE:
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if (sk != mrt->mroute_sk)
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if (sk != rcu_dereference_raw(mrt->mroute_sk))
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return -EACCES;
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return ip_ra_control(sk, 0, NULL);
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case MRT_ADD_VIF:
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@ -1246,7 +1248,8 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, unsi
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return -ENFILE;
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rtnl_lock();
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if (optname == MRT_ADD_VIF) {
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ret = vif_add(net, mrt, &vif, sk == mrt->mroute_sk);
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ret = vif_add(net, mrt, &vif,
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sk == rtnl_dereference(mrt->mroute_sk));
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} else {
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ret = vif_delete(mrt, vif.vifc_vifi, 0, NULL);
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}
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@ -1267,7 +1270,8 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, unsi
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if (optname == MRT_DEL_MFC)
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ret = ipmr_mfc_delete(mrt, &mfc);
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else
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ret = ipmr_mfc_add(net, mrt, &mfc, sk == mrt->mroute_sk);
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ret = ipmr_mfc_add(net, mrt, &mfc,
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sk == rtnl_dereference(mrt->mroute_sk));
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rtnl_unlock();
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return ret;
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/*
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@ -1309,14 +1313,16 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, unsi
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return -EINVAL;
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if (get_user(v, (u32 __user *)optval))
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return -EFAULT;
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if (sk == mrt->mroute_sk)
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return -EBUSY;
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rtnl_lock();
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ret = 0;
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if (!ipmr_new_table(net, v))
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ret = -ENOMEM;
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raw_sk(sk)->ipmr_table = v;
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if (sk == rtnl_dereference(mrt->mroute_sk)) {
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ret = -EBUSY;
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} else {
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if (!ipmr_new_table(net, v))
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ret = -ENOMEM;
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raw_sk(sk)->ipmr_table = v;
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}
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rtnl_unlock();
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return ret;
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}
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@ -1713,6 +1719,7 @@ dont_forward:
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/*
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* Multicast packets for forwarding arrive here
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* Called with rcu_read_lock();
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*/
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int ip_mr_input(struct sk_buff *skb)
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@ -1726,7 +1733,7 @@ int ip_mr_input(struct sk_buff *skb)
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/* Packet is looped back after forward, it should not be
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forwarded second time, but still can be delivered locally.
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*/
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if (IPCB(skb)->flags&IPSKB_FORWARDED)
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if (IPCB(skb)->flags & IPSKB_FORWARDED)
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goto dont_forward;
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err = ipmr_fib_lookup(net, &skb_rtable(skb)->fl, &mrt);
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@ -1736,24 +1743,24 @@ int ip_mr_input(struct sk_buff *skb)
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}
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if (!local) {
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if (IPCB(skb)->opt.router_alert) {
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if (ip_call_ra_chain(skb))
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return 0;
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} else if (ip_hdr(skb)->protocol == IPPROTO_IGMP){
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/* IGMPv1 (and broken IGMPv2 implementations sort of
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Cisco IOS <= 11.2(8)) do not put router alert
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option to IGMP packets destined to routable
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groups. It is very bad, because it means
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that we can forward NO IGMP messages.
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*/
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read_lock(&mrt_lock);
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if (mrt->mroute_sk) {
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nf_reset(skb);
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raw_rcv(mrt->mroute_sk, skb);
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read_unlock(&mrt_lock);
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return 0;
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}
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read_unlock(&mrt_lock);
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if (IPCB(skb)->opt.router_alert) {
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if (ip_call_ra_chain(skb))
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return 0;
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} else if (ip_hdr(skb)->protocol == IPPROTO_IGMP) {
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/* IGMPv1 (and broken IGMPv2 implementations sort of
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* Cisco IOS <= 11.2(8)) do not put router alert
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* option to IGMP packets destined to routable
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* groups. It is very bad, because it means
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* that we can forward NO IGMP messages.
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*/
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struct sock *mroute_sk;
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mroute_sk = rcu_dereference(mrt->mroute_sk);
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if (mroute_sk) {
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nf_reset(skb);
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raw_rcv(mroute_sk, skb);
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return 0;
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}
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}
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}
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