netfilter: nfnetlink: add mutex per subsystem

This patch replaces the global lock to one lock per subsystem.
The per-subsystem lock avoids that processes operating
with different subsystems are synchronized.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/include/linux/netfilter/nfnetlink.h b/include/linux/netfilter/nfnetlink.h
index 4966dde..ecbb8e4 100644 (file)
--- a/include/linux/netfilter/nfnetlink.h
+++ b/include/linux/netfilter/nfnetlink.h
@@ -34,8 +34,8 @@ extern int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 pid, unsigne
 extern int nfnetlink_set_err(struct net *net, u32 pid, u32 group, int error);
 extern int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u_int32_t pid, int flags);
 
-extern void nfnl_lock(void);
-extern void nfnl_unlock(void);
+extern void nfnl_lock(__u8 subsys_id);
+extern void nfnl_unlock(__u8 subsys_id);
 
 #define MODULE_ALIAS_NFNL_SUBSYS(subsys) \
        MODULE_ALIAS("nfnetlink-subsys-" __stringify(subsys))

diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index 6d6d8f2..f82b2e6 100644 (file)
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -88,14 +88,14 @@ find_set_type(const char *name, u8 family, u8 revision)
 static bool
 load_settype(const char *name)
 {
-       nfnl_unlock();
+       nfnl_unlock(NFNL_SUBSYS_IPSET);
        pr_debug("try to load ip_set_%s\n", name);
        if (request_module("ip_set_%s", name) < 0) {
                pr_warning("Can't find ip_set type %s\n", name);
-               nfnl_lock();
+               nfnl_lock(NFNL_SUBSYS_IPSET);
                return false;
        }
-       nfnl_lock();
+       nfnl_lock(NFNL_SUBSYS_IPSET);
        return true;
 }
 
@@ -532,7 +532,7 @@ ip_set_nfnl_get(const char *name)
        ip_set_id_t i, index = IPSET_INVALID_ID;
        struct ip_set *s;
 
-       nfnl_lock();
+       nfnl_lock(NFNL_SUBSYS_IPSET);
        for (i = 0; i < ip_set_max; i++) {
                s = nfnl_set(i);
                if (s != NULL && STREQ(s->name, name)) {
@@ -541,7 +541,7 @@ ip_set_nfnl_get(const char *name)
                        break;
                }
        }
-       nfnl_unlock();
+       nfnl_unlock(NFNL_SUBSYS_IPSET);
 
        return index;
 }
@@ -561,13 +561,13 @@ ip_set_nfnl_get_byindex(ip_set_id_t index)
        if (index > ip_set_max)
                return IPSET_INVALID_ID;
 
-       nfnl_lock();
+       nfnl_lock(NFNL_SUBSYS_IPSET);
        set = nfnl_set(index);
        if (set)
                __ip_set_get(set);
        else
                index = IPSET_INVALID_ID;
-       nfnl_unlock();
+       nfnl_unlock(NFNL_SUBSYS_IPSET);
 
        return index;
 }
@@ -584,11 +584,11 @@ void
 ip_set_nfnl_put(ip_set_id_t index)
 {
        struct ip_set *set;
-       nfnl_lock();
+       nfnl_lock(NFNL_SUBSYS_IPSET);
        set = nfnl_set(index);
        if (set != NULL)
                __ip_set_put(set);
-       nfnl_unlock();
+       nfnl_unlock(NFNL_SUBSYS_IPSET);
 }
 EXPORT_SYMBOL_GPL(ip_set_nfnl_put);
 
@@ -1763,10 +1763,10 @@ ip_set_sockfn_get(struct sock *sk, int optval, void __user *user, int *len)
                        goto done;
                }
                req_get->set.name[IPSET_MAXNAMELEN - 1] = '\0';
-               nfnl_lock();
+               nfnl_lock(NFNL_SUBSYS_IPSET);
                find_set_and_id(req_get->set.name, &id);
                req_get->set.index = id;
-               nfnl_unlock();
+               nfnl_unlock(NFNL_SUBSYS_IPSET);
                goto copy;
        }
        case IP_SET_OP_GET_BYINDEX: {
@@ -1778,11 +1778,11 @@ ip_set_sockfn_get(struct sock *sk, int optval, void __user *user, int *len)
                        ret = -EINVAL;
                        goto done;
                }
-               nfnl_lock();
+               nfnl_lock(NFNL_SUBSYS_IPSET);
                set = nfnl_set(req_get->set.index);
                strncpy(req_get->set.name, set ? set->name : "",
                        IPSET_MAXNAMELEN);
-               nfnl_unlock();
+               nfnl_unlock(NFNL_SUBSYS_IPSET);
                goto copy;
        }
        default:

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 2334cc5..d490a30 100644 (file)
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1256,13 +1256,13 @@ ctnetlink_parse_nat_setup(struct nf_conn *ct,
        if (!parse_nat_setup) {
 #ifdef CONFIG_MODULES
                rcu_read_unlock();
-               nfnl_unlock();
+               nfnl_unlock(NFNL_SUBSYS_CTNETLINK);
                if (request_module("nf-nat") < 0) {
-                       nfnl_lock();
+                       nfnl_lock(NFNL_SUBSYS_CTNETLINK);
                        rcu_read_lock();
                        return -EOPNOTSUPP;
                }
-               nfnl_lock();
+               nfnl_lock(NFNL_SUBSYS_CTNETLINK);
                rcu_read_lock();
                if (nfnetlink_parse_nat_setup_hook)
                        return -EAGAIN;
@@ -1274,13 +1274,13 @@ ctnetlink_parse_nat_setup(struct nf_conn *ct,
        if (err == -EAGAIN) {
 #ifdef CONFIG_MODULES
                rcu_read_unlock();
-               nfnl_unlock();
+               nfnl_unlock(NFNL_SUBSYS_CTNETLINK);
                if (request_module("nf-nat-%u", nf_ct_l3num(ct)) < 0) {
-                       nfnl_lock();
+                       nfnl_lock(NFNL_SUBSYS_CTNETLINK);
                        rcu_read_lock();
                        return -EOPNOTSUPP;
                }
-               nfnl_lock();
+               nfnl_lock(NFNL_SUBSYS_CTNETLINK);
                rcu_read_lock();
 #else
                err = -EOPNOTSUPP;

diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 58a09b7..d578ec2 100644 (file)
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -36,8 +36,10 @@ MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
 
 static char __initdata nfversion[] = "0.30";
 
-static const struct nfnetlink_subsystem __rcu *subsys_table[NFNL_SUBSYS_COUNT];
-static DEFINE_MUTEX(nfnl_mutex);
+static struct {
+       struct mutex                            mutex;
+       const struct nfnetlink_subsystem __rcu  *subsys;
+} table[NFNL_SUBSYS_COUNT];
 
 static const int nfnl_group2type[NFNLGRP_MAX+1] = {
        [NFNLGRP_CONNTRACK_NEW]         = NFNL_SUBSYS_CTNETLINK,
@@ -48,27 +50,32 @@ static const int nfnl_group2type[NFNLGRP_MAX+1] = {
        [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
 };
 
-void nfnl_lock(void)
+void nfnl_lock(__u8 subsys_id)
 {
-       mutex_lock(&nfnl_mutex);
+       mutex_lock(&table[subsys_id].mutex);
 }
 EXPORT_SYMBOL_GPL(nfnl_lock);
 
-void nfnl_unlock(void)
+void nfnl_unlock(__u8 subsys_id)
 {
-       mutex_unlock(&nfnl_mutex);
+       mutex_unlock(&table[subsys_id].mutex);
 }
 EXPORT_SYMBOL_GPL(nfnl_unlock);
 
+static struct mutex *nfnl_get_lock(__u8 subsys_id)
+{
+       return &table[subsys_id].mutex;
+}
+
 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
 {
-       nfnl_lock();
-       if (subsys_table[n->subsys_id]) {
-               nfnl_unlock();
+       nfnl_lock(n->subsys_id);
+       if (table[n->subsys_id].subsys) {
+               nfnl_unlock(n->subsys_id);
                return -EBUSY;
        }
-       rcu_assign_pointer(subsys_table[n->subsys_id], n);
-       nfnl_unlock();
+       rcu_assign_pointer(table[n->subsys_id].subsys, n);
+       nfnl_unlock(n->subsys_id);
 
        return 0;
 }
@@ -76,9 +83,9 @@ EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
 
 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
 {
-       nfnl_lock();
-       subsys_table[n->subsys_id] = NULL;
-       nfnl_unlock();
+       nfnl_lock(n->subsys_id);
+       table[n->subsys_id].subsys = NULL;
+       nfnl_unlock(n->subsys_id);
        synchronize_rcu();
        return 0;
 }
@@ -91,7 +98,7 @@ static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t t
        if (subsys_id >= NFNL_SUBSYS_COUNT)
                return NULL;
 
-       return rcu_dereference(subsys_table[subsys_id]);
+       return rcu_dereference(table[subsys_id].subsys);
 }
 
 static inline const struct nfnl_callback *
@@ -175,6 +182,7 @@ replay:
                struct nlattr *cda[ss->cb[cb_id].attr_count + 1];
                struct nlattr *attr = (void *)nlh + min_len;
                int attrlen = nlh->nlmsg_len - min_len;
+               __u8 subsys_id = NFNL_SUBSYS_ID(type);
 
                err = nla_parse(cda, ss->cb[cb_id].attr_count,
                                attr, attrlen, ss->cb[cb_id].policy);
@@ -189,10 +197,9 @@ replay:
                        rcu_read_unlock();
                } else {
                        rcu_read_unlock();
-                       nfnl_lock();
-                       if (rcu_dereference_protected(
-                                       subsys_table[NFNL_SUBSYS_ID(type)],
-                                       lockdep_is_held(&nfnl_mutex)) != ss ||
+                       nfnl_lock(subsys_id);
+                       if (rcu_dereference_protected(table[subsys_id].subsys,
+                               lockdep_is_held(nfnl_get_lock(subsys_id))) != ss ||
                            nfnetlink_find_client(type, ss) != nc)
                                err = -EAGAIN;
                        else if (nc->call)
@@ -200,7 +207,7 @@ replay:
                                                   (const struct nlattr **)cda);
                        else
                                err = -EINVAL;
-                       nfnl_unlock();
+                       nfnl_unlock(subsys_id);
                }
                if (err == -EAGAIN)
                        goto replay;
@@ -267,6 +274,11 @@ static struct pernet_operations nfnetlink_net_ops = {
 
 static int __init nfnetlink_init(void)
 {
+       int i;
+
+       for (i=0; i<NFNL_SUBSYS_COUNT; i++)
+               mutex_init(&table[i].mutex);
+
        pr_info("Netfilter messages via NETLINK v%s.\n", nfversion);
        return register_pernet_subsys(&nfnetlink_net_ops);
 }