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Message-Id: <1519165995-50854-3-git-send-email-yuvalm@mellanox.com>
Date: Wed, 21 Feb 2018 00:33:06 +0200
From: Yuval Mintz <yuvalm@...lanox.com>
To: netdev@...r.kernel.org
Cc: mlxsw@...lanox.com, kuznet@....inr.ac.ru, yoshfuji@...ux-ipv6.org,
nikolay@...ulusnetworks.com, Yuval Mintz <yuvalm@...lanox.com>
Subject: [RFC net-next 02/11] ip6mr: Make mroute_sk rcu-based
In ipmr the mr_table socket is handled under RCU. Introduce the same
for ip6mr.
Signed-off-by: Yuval Mintz <yuvalm@...lanox.com>
---
include/linux/mroute6.h | 6 +++---
net/ipv6/ip6_output.c | 2 +-
net/ipv6/ip6mr.c | 43 ++++++++++++++++++++++++++-----------------
3 files changed, 30 insertions(+), 21 deletions(-)
diff --git a/include/linux/mroute6.h b/include/linux/mroute6.h
index e5e5b82..e1b9fb0 100644
--- a/include/linux/mroute6.h
+++ b/include/linux/mroute6.h
@@ -111,12 +111,12 @@ extern int ip6mr_get_route(struct net *net, struct sk_buff *skb,
struct rtmsg *rtm, u32 portid);
#ifdef CONFIG_IPV6_MROUTE
-extern struct sock *mroute6_socket(struct net *net, struct sk_buff *skb);
+bool mroute6_is_socket(struct net *net, struct sk_buff *skb);
extern int ip6mr_sk_done(struct sock *sk);
#else
-static inline struct sock *mroute6_socket(struct net *net, struct sk_buff *skb)
+static inline bool mroute6_is_socket(struct net *net, struct sk_buff *skb)
{
- return NULL;
+ return false;
}
static inline int ip6mr_sk_done(struct sock *sk)
{
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 997c7f1..a6eb0e6 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -71,7 +71,7 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *
struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(sk) &&
- ((mroute6_socket(net, skb) &&
+ ((mroute6_is_socket(net, skb) &&
!(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||
ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
&ipv6_hdr(skb)->saddr))) {
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index e397990..7792fc5 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -58,7 +58,7 @@ struct mr6_table {
struct list_head list;
possible_net_t net;
u32 id;
- struct sock *mroute6_sk;
+ struct sock __rcu *mroute6_sk;
struct timer_list ipmr_expire_timer;
struct list_head mfc6_unres_queue;
struct list_head mfc6_cache_array[MFC6_LINES];
@@ -1121,6 +1121,7 @@ static void ip6mr_cache_resolve(struct net *net, struct mr6_table *mrt,
static int ip6mr_cache_report(struct mr6_table *mrt, struct sk_buff *pkt,
mifi_t mifi, int assert)
{
+ struct sock *mroute6_sk;
struct sk_buff *skb;
struct mrt6msg *msg;
int ret;
@@ -1190,17 +1191,19 @@ static int ip6mr_cache_report(struct mr6_table *mrt, struct sk_buff *pkt,
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
- if (!mrt->mroute6_sk) {
+ rcu_read_lock();
+ mroute6_sk = rcu_dereference(mrt->mroute6_sk);
+ if (!mroute6_sk) {
+ rcu_read_unlock();
kfree_skb(skb);
return -EINVAL;
}
mrt6msg_netlink_event(mrt, skb);
- /*
- * Deliver to user space multicast routing algorithms
- */
+ /* Deliver to user space multicast routing algorithms */
ret = sock_queue_rcv_skb(mrt->mroute6_sk, skb);
+ rcu_read_unlock();
if (ret < 0) {
net_warn_ratelimited("mroute6: pending queue full, dropping entries\n");
kfree_skb(skb);
@@ -1584,11 +1587,11 @@ static int ip6mr_sk_init(struct mr6_table *mrt, struct sock *sk)
rtnl_lock();
write_lock_bh(&mrt_lock);
- if (likely(mrt->mroute6_sk == NULL)) {
- mrt->mroute6_sk = sk;
- net->ipv6.devconf_all->mc_forwarding++;
- } else {
+ if (rtnl_dereference(mrt->mroute6_sk)) {
err = -EADDRINUSE;
+ } else {
+ rcu_assign_pointer(mrt->mroute6_sk, sk);
+ net->ipv6.devconf_all->mc_forwarding++;
}
write_unlock_bh(&mrt_lock);
@@ -1614,9 +1617,9 @@ int ip6mr_sk_done(struct sock *sk)
rtnl_lock();
ip6mr_for_each_table(mrt, net) {
- if (sk == mrt->mroute6_sk) {
+ if (sk == rtnl_dereference(mrt->mroute6_sk)) {
write_lock_bh(&mrt_lock);
- mrt->mroute6_sk = NULL;
+ RCU_INIT_POINTER(mrt->mroute6_sk, NULL);
net->ipv6.devconf_all->mc_forwarding--;
write_unlock_bh(&mrt_lock);
inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
@@ -1630,11 +1633,12 @@ int ip6mr_sk_done(struct sock *sk)
}
}
rtnl_unlock();
+ synchronize_rcu();
return err;
}
-struct sock *mroute6_socket(struct net *net, struct sk_buff *skb)
+bool mroute6_is_socket(struct net *net, struct sk_buff *skb)
{
struct mr6_table *mrt;
struct flowi6 fl6 = {
@@ -1646,8 +1650,9 @@ struct sock *mroute6_socket(struct net *net, struct sk_buff *skb)
if (ip6mr_fib_lookup(net, &fl6, &mrt) < 0)
return NULL;
- return mrt->mroute6_sk;
+ return rcu_access_pointer(mrt->mroute6_sk);
}
+EXPORT_SYMBOL(mroute6_is_socket);
/*
* Socket options and virtual interface manipulation. The whole
@@ -1674,7 +1679,8 @@ int ip6_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, uns
return -ENOENT;
if (optname != MRT6_INIT) {
- if (sk != mrt->mroute6_sk && !ns_capable(net->user_ns, CAP_NET_ADMIN))
+ if (sk != rcu_access_pointer(mrt->mroute6_sk) &&
+ !ns_capable(net->user_ns, CAP_NET_ADMIN))
return -EACCES;
}
@@ -1696,7 +1702,8 @@ int ip6_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, uns
if (vif.mif6c_mifi >= MAXMIFS)
return -ENFILE;
rtnl_lock();
- ret = mif6_add(net, mrt, &vif, sk == mrt->mroute6_sk);
+ ret = mif6_add(net, mrt, &vif,
+ sk == rtnl_dereference(mrt->mroute6_sk));
rtnl_unlock();
return ret;
@@ -1731,7 +1738,9 @@ int ip6_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, uns
ret = ip6mr_mfc_delete(mrt, &mfc, parent);
else
ret = ip6mr_mfc_add(net, mrt, &mfc,
- sk == mrt->mroute6_sk, parent);
+ sk ==
+ rtnl_dereference(mrt->mroute6_sk),
+ parent);
rtnl_unlock();
return ret;
@@ -1783,7 +1792,7 @@ int ip6_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, uns
/* "pim6reg%u" should not exceed 16 bytes (IFNAMSIZ) */
if (v != RT_TABLE_DEFAULT && v >= 100000000)
return -EINVAL;
- if (sk == mrt->mroute6_sk)
+ if (sk == rcu_access_pointer(mrt->mroute6_sk))
return -EBUSY;
rtnl_lock();
--
2.4.3
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