Eighteen months ago, in linux-kernel@ discussed patch
"[PATCH] netfilter: add per-namespace logging to nfnetlink_log.c"
Author: Rainer Weikusat <rweikusat [at] mobileactivedefense>
Why patch for nflog was not accepted in kernel ?
After applying the patch "NFLOG" works in the container. Tested on
kernel version 3.4.22.
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index 66b2c54..23a1c16 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -39,6 +39,10 @@
#include "../bridge/br_private.h"
#endif
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+
+
#define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
#define NFULNL_TIMEOUT_DEFAULT 100 /* every second */
#define NFULNL_QTHRESH_DEFAULT 100 /* 100 packets */
@@ -47,6 +51,16 @@
#define PRINTR(x, args...) do { if (net_ratelimit()) \
printk(x, ## args); } while (0);
+#define INSTANCE_BUCKETS 16
+
+struct nfulnl_instances {
+ spinlock_t lock;
+ atomic_t global_seq;
+ struct hlist_head table[INSTANCE_BUCKETS];
+ struct net *net;
+};
+
+
struct nfulnl_instance {
struct hlist_node hlist; /* global list of instances */
spinlock_t lock;
@@ -67,14 +81,45 @@ struct nfulnl_instance {
u_int16_t flags;
u_int8_t copy_mode;
struct rcu_head rcu;
+ struct nfulnl_instances *instances;
};
-static DEFINE_SPINLOCK(instances_lock);
-static atomic_t global_seq;
+static struct nfulnl_instances *instances;
+static int nfulnl_net_id;
+
-#define INSTANCE_BUCKETS 16
-static struct hlist_head instance_table[INSTANCE_BUCKETS];
-static unsigned int hash_init;
+#ifdef CONFIG_NET_NS
+static inline struct nfulnl_instances *instances_for_net(struct net *net)
+{
+ return net_generic(net, nfulnl_net_id);
+}
+#else
+static inline struct nfulnl_instances *instances_for_net(struct net *net)
+{
+ return instances;
+}
+#endif
+
+static struct nfulnl_instances *instances_via_skb(struct sk_buff const *skb)
+{
+ static struct net *dummy_pnet __maybe_unused;
+ struct net *net;
+
+ /*
+ * The multiway conditional needs to be inside the
+ * read_pnet argument list because that is a no-op for
+ * the 'no netns' case and gcc will then [hopefully]
+ * remove it as 'dead code' (at least 4.4.5 does).
+ */
+ net = read_pnet(skb->sk ? &skb->sk->sk_net :
+ (skb->dev ? &skb->dev->nd_net : &dummy_pnet));
+ return net ? instances_for_net(net) : NULL;
+}
+
+static inline struct net *inst_net(struct nfulnl_instance *inst)
+{
+ return read_pnet(&inst->instances->net);
+}
static inline u_int8_t instance_hashfn(u_int16_t group_num)
{
@@ -82,13 +127,13 @@ static inline u_int8_t instance_hashfn(u_int16_t group_num)
}
static struct nfulnl_instance *
-__instance_lookup(u_int16_t group_num)
+__instance_lookup(struct nfulnl_instances *instances, u_int16_t group_num)
{
struct hlist_head *head;
struct hlist_node *pos;
struct nfulnl_instance *inst;
- head = &instance_table[instance_hashfn(group_num)];
+ head = &instances->table[instance_hashfn(group_num)];
hlist_for_each_entry_rcu(inst, pos, head, hlist) {
if (inst->group_num == group_num)
return inst;
@@ -103,12 +148,14 @@ instance_get(struct nfulnl_instance *inst)
}
static struct nfulnl_instance *
-instance_lookup_get(u_int16_t group_num)
+instance_lookup_get(struct nfulnl_instances *instances, u_int16_t group_num)
{
struct nfulnl_instance *inst;
+ if(!instances)
+ return NULL;
rcu_read_lock_bh();
- inst = __instance_lookup(group_num);
+ inst = __instance_lookup(instances,group_num);
if (inst && !atomic_inc_not_zero(&inst->use))
inst = NULL;
rcu_read_unlock_bh();
@@ -132,13 +179,13 @@ instance_put(struct nfulnl_instance *inst)
static void nfulnl_timer(unsigned long data);
static struct nfulnl_instance *
-instance_create(u_int16_t group_num, int pid)
+instance_create(struct nfulnl_instances *instances, u_int16_t group_num, int pid)
{
struct nfulnl_instance *inst;
int err;
- spin_lock_bh(&instances_lock);
- if (__instance_lookup(group_num)) {
+ spin_lock_bh(&instances->lock);
+ if (__instance_lookup(instances, group_num)) {
err = -EEXIST;
goto out_unlock;
}
@@ -171,15 +218,16 @@ instance_create(u_int16_t group_num, int pid)
inst->copy_mode = NFULNL_COPY_PACKET;
inst->copy_range = NFULNL_COPY_RANGE_MAX;
- hlist_add_head_rcu(&inst->hlist,
- &instance_table[instance_hashfn(group_num)]);
+ inst->instances = instances;
- spin_unlock_bh(&instances_lock);
+ hlist_add_head_rcu(&inst->hlist,
+ &instances->table[instance_hashfn(group_num)]);
+ spin_unlock_bh(&instances->lock);
return inst;
out_unlock:
- spin_unlock_bh(&instances_lock);
+ spin_unlock_bh(&instances->lock);
return ERR_PTR(err);
}
@@ -208,11 +256,12 @@ __instance_destroy(struct nfulnl_instance *inst)
}
static inline void
-instance_destroy(struct nfulnl_instance *inst)
+instance_destroy(struct nfulnl_instances *instances,
+ struct nfulnl_instance *inst)
{
- spin_lock_bh(&instances_lock);
+ spin_lock_bh(&instances->lock);
__instance_destroy(inst);
- spin_unlock_bh(&instances_lock);
+ spin_unlock_bh(&instances->lock);
}
static int
@@ -331,7 +380,7 @@ __nfulnl_send(struct nfulnl_instance *inst)
NLMSG_DONE,
sizeof(struct nfgenmsg));
- status = nfnetlink_unicast(inst->skb, &init_net, inst->peer_pid,
+ status = nfnetlink_unicast(inst->skb, inst_net(inst), inst->peer_pid,
MSG_DONTWAIT);
inst->qlen = 0;
@@ -502,7 +551,7 @@ __build_packet_message(struct nfulnl_instance *inst,
/* global sequence number */
if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
NLA_PUT_BE32(inst->skb, NFULA_SEQ_GLOBAL,
- htonl(atomic_inc_return(&global_seq)));
+ htonl(atomic_inc_return(&inst->instances->global_seq)));
if (data_len) {
struct nlattr *nla;
@@ -564,7 +613,7 @@ nfulnl_log_packet(u_int8_t pf,
else
li = &default_loginfo;
- inst = instance_lookup_get(li->u.ulog.group);
+ inst = instance_lookup_get(instances_via_skb(skb),li->u.ulog.group);
if (!inst)
return;
@@ -675,24 +724,25 @@ nfulnl_rcv_nl_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct netlink_notify *n = ptr;
+ struct nfulnl_instances *instances;
if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
int i;
+ instances = instances_for_net(n->net);
/* destroy all instances for this pid */
- spin_lock_bh(&instances_lock);
+ spin_lock_bh(&instances->lock);
for (i = 0; i < INSTANCE_BUCKETS; i++) {
struct hlist_node *tmp, *t2;
struct nfulnl_instance *inst;
- struct hlist_head *head = &instance_table[i];
+ struct hlist_head *head = &instances->table[i];
hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
- if ((net_eq(n->net, &init_net)) &&
- (n->pid == inst->peer_pid))
+ if (n->pid == inst->peer_pid)
__instance_destroy(inst);
}
}
- spin_unlock_bh(&instances_lock);
+ spin_unlock_bh(&instances->lock);
}
return NOTIFY_DONE;
}
@@ -731,6 +781,7 @@ nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
{
struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
u_int16_t group_num = ntohs(nfmsg->res_id);
+ struct nfulnl_instances *instances;
struct nfulnl_instance *inst;
struct nfulnl_msg_config_cmd *cmd = NULL;
int ret = 0;
@@ -748,8 +799,11 @@ nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
return 0;
}
}
+ instances = instances_via_skb(skb);
+ if (!instances)
+ return -ENODEV;
- inst = instance_lookup_get(group_num);
+ inst = instance_lookup_get(instances,group_num);
if (inst && inst->peer_pid != NETLINK_CB(skb).pid) {
ret = -EPERM;
goto out_put;
@@ -763,7 +817,7 @@ nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
goto out_put;
}
- inst = instance_create(group_num,
+ inst = instance_create(instances,group_num,
NETLINK_CB(skb).pid);
if (IS_ERR(inst)) {
ret = PTR_ERR(inst);
@@ -776,7 +830,7 @@ nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
goto out;
}
- instance_destroy(inst);
+ instance_destroy(instances,inst);
goto out_put;
default:
ret = -ENOTSUPP;
@@ -860,16 +914,28 @@ static const struct nfnetlink_subsystem nfulnl_subsys = {
#ifdef CONFIG_PROC_FS
struct iter_state {
unsigned int bucket;
+ struct nfulnl_instances *instances;
};
+static inline struct nfulnl_instances *instances_for_seq(void)
+{
+ return instances_for_net(&init_net);
+}
+
+
static struct hlist_node *get_first(struct iter_state *st)
{
if (!st)
return NULL;
+ st->instances = instances_for_seq();
+
for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
- if (!hlist_empty(&instance_table[st->bucket]))
- return rcu_dereference_bh(hlist_first_rcu(&instance_table[st->bucket]));
+ if (!hlist_empty(&st->instances->table[st->bucket]))
+ return rcu_dereference_bh(
+ hlist_first_rcu(
+ &st->instances->table[st->bucket]));
+
}
return NULL;
}
@@ -881,7 +947,7 @@ static struct hlist_node *get_next(struct iter_state *st, struct hlist_node *h)
if (++st->bucket >= INSTANCE_BUCKETS)
return NULL;
- h = rcu_dereference_bh(hlist_first_rcu(&instance_table[st->bucket]));
+ h = rcu_dereference_bh(hlist_first_rcu(&st->instances->table[st->bucket]));
}
return h;
}
@@ -950,17 +1016,42 @@ static const struct file_operations nful_file_ops = {
#endif /* PROC_FS */
+
+
+static int nfulnl_net_init(struct net *net)
+{
+ struct nfulnl_instances *insts;
+ int i;
+
+ insts = net_generic(net, nfulnl_net_id);
+ insts->net = net;
+ spin_lock_init(&insts->lock);
+
+ i = INSTANCE_BUCKETS;
+ do INIT_HLIST_HEAD(insts->table + --i); while (i);
+
+ /* avoid 'runtime' net_generic for 'no netns' */
+ instances = insts;
+ return 0;
+}
+
+static struct pernet_operations nfulnl_net_ops = {
+ .init = nfulnl_net_init,
+ .id = &nfulnl_net_id,
+ .size = sizeof(struct nfulnl_instances)
+};
+
static int __init nfnetlink_log_init(void)
{
- int i, status = -ENOMEM;
+ int status = -ENOMEM;
+ status = register_pernet_subsys(&nfulnl_net_ops);
+ if (status)
+ return status;
- for (i = 0; i < INSTANCE_BUCKETS; i++)
- INIT_HLIST_HEAD(&instance_table[i]);
/* it's not really all that important to have a random value, so
* we can do this from the init function, even if there hasn't
* been that much entropy yet */
- get_random_bytes(&hash_init, sizeof(hash_init));
netlink_register_notifier(&nfulnl_rtnl_notifier);
status = nfnetlink_subsys_register(&nfulnl_subsys);
@@ -995,6 +1086,7 @@ cleanup_netlink_notifier:
static void __exit nfnetlink_log_fini(void)
{
+ unregister_pernet_subsys(&nfulnl_net_ops);
nf_log_unregister(&nfulnl_logger);
#ifdef CONFIG_PROC_FS
remove_proc_entry("nfnetlink_log", proc_net_netfilter);
