netfilter 29/62: nf_conntrack: support conntrack templates

Patrick McHardy
2010-02-16T14:56:01Z

commit b2a15a604d379af323645e330638e2cfcc696aff
Author: Patrick McHardy <kaber@trash.net>
Date: Wed Feb 3 14:13:03 2010 +0100

netfilter: nf_conntrack: support conntrack templates

Support initializing selected parameters of new conntrack entries from a
"conntrack template", which is a specially marked conntrack entry attached
to the skb.

Currently the helper and the event delivery masks can be initialized this
way.

Signed-off-by: Patrick McHardy <kaber@trash.net>

diff --git a/include/linux/netfilter/nf_conntrack_common.h b/include/linux/netfilter/nf_conntrack_common.h
index ebfed90..c608677 100644
--- a/include/linux/netfilter/nf_conntrack_common.h
+++ b/include/linux/netfilter/nf_conntrack_common.h
@@ -72,6 +72,10 @@ enum ip_conntrack_status {
/* Connection has fixed timeout. */
IPS_FIXED_TIMEOUT_BIT = 10,
IPS_FIXED_TIMEOUT = (1 << IPS_FIXED_TIMEOUT_BIT),
+
+ /* Conntrack is a template */
+ IPS_TEMPLATE_BIT = 11,
+ IPS_TEMPLATE = (1 << IPS_TEMPLATE_BIT),
};

/* Connection tracking event types */
diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index a0904ad..5043d61 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -272,6 +272,11 @@ nf_conntrack_alloc(struct net *net,
const struct nf_conntrack_tuple *repl,
gfp_t gfp);

+static inline int nf_ct_is_template(const struct nf_conn *ct)
+{
+ return test_bit(IPS_TEMPLATE_BIT, &ct->status);
+}
+
/* It's confirmed if it is, or has been in the hash table. */
static inline int nf_ct_is_confirmed(struct nf_conn *ct)
{
diff --git a/include/net/netfilter/nf_conntrack_helper.h b/include/net/netfilter/nf_conntrack_helper.h
index 86be7c4..e17aaa3 100644
--- a/include/net/netfilter/nf_conntrack_helper.h
+++ b/include/net/netfilter/nf_conntrack_helper.h
@@ -47,7 +47,8 @@ extern void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);

extern struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp);

-extern int __nf_ct_try_assign_helper(struct nf_conn *ct, gfp_t flags);
+extern int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
+ gfp_t flags);

extern void nf_ct_helper_destroy(struct nf_conn *ct);

diff --git a/net/ipv4/netfilter/nf_defrag_ipv4.c b/net/ipv4/netfilter/nf_defrag_ipv4.c
index 331ead3..77627fa 100644
--- a/net/ipv4/netfilter/nf_defrag_ipv4.c
+++ b/net/ipv4/netfilter/nf_defrag_ipv4.c
@@ -59,7 +59,7 @@ static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
#if !defined(CONFIG_NF_NAT) && !defined(CONFIG_NF_NAT_MODULE)
/* Previously seen (loopback)? Ignore. Do this before
fragment check. */
- if (skb->nfct)
+ if (skb->nfct && !nf_ct_is_template((struct nf_conn *)skb->nfct))
return NF_ACCEPT;
#endif
#endif
diff --git a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
index 0956eba..55ce22e 100644
--- a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
+++ b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
@@ -212,7 +212,7 @@ static unsigned int ipv6_defrag(unsigned int hooknum,
struct sk_buff *reasm;

/* Previously seen (loopback)? */
- if (skb->nfct)
+ if (skb->nfct && !nf_ct_is_template((struct nf_conn *)skb->nfct))
return NF_ACCEPT;

reasm = nf_ct_frag6_gather(skb, nf_ct6_defrag_user(hooknum, skb));
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 53b8da6..471e2a7 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -618,7 +618,7 @@ EXPORT_SYMBOL_GPL(nf_conntrack_free);
/* Allocate a new conntrack: we return -ENOMEM if classification
failed due to stress. Otherwise it really is unclassifiable. */
static struct nf_conntrack_tuple_hash *
-init_conntrack(struct net *net,
+init_conntrack(struct net *net, struct nf_conn *tmpl,
const struct nf_conntrack_tuple *tuple,
struct nf_conntrack_l3proto *l3proto,
struct nf_conntrack_l4proto *l4proto,
@@ -628,6 +628,7 @@ init_conntrack(struct net *net,
struct nf_conn *ct;
struct nf_conn_help *help;
struct nf_conntrack_tuple repl_tuple;
+ struct nf_conntrack_ecache *ecache;
struct nf_conntrack_expect *exp;

if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
@@ -648,7 +649,11 @@ init_conntrack(struct net *net,
}

nf_ct_acct_ext_add(ct, GFP_ATOMIC);
- nf_ct_ecache_ext_add(ct, 0, 0, GFP_ATOMIC);
+
+ ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
+ nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
+ ecache ? ecache->expmask : 0,
+ GFP_ATOMIC);

spin_lock_bh(&nf_conntrack_lock);
exp = nf_ct_find_expectation(net, tuple);
@@ -673,7 +678,7 @@ init_conntrack(struct net *net,
nf_conntrack_get(&ct->master->ct_general);
NF_CT_STAT_INC(net, expect_new);
} else {
- __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
+ __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
NF_CT_STAT_INC(net, new);
}

@@ -694,7 +699,7 @@ init_conntrack(struct net *net,

/* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
static inline struct nf_conn *
-resolve_normal_ct(struct net *net,
+resolve_normal_ct(struct net *net, struct nf_conn *tmpl,
struct sk_buff *skb,
unsigned int dataoff,
u_int16_t l3num,
@@ -718,7 +723,8 @@ resolve_normal_ct(struct net *net,
/* look for tuple match */
h = nf_conntrack_find_get(net, &tuple);
if (!h) {
- h = init_conntrack(net, &tuple, l3proto, l4proto, skb, dataoff);
+ h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto,
+ skb, dataoff);
if (!h)
return NULL;
if (IS_ERR(h))
@@ -755,7 +761,7 @@ unsigned int
nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
struct sk_buff *skb)
{
- struct nf_conn *ct;
+ struct nf_conn *ct, *tmpl = NULL;
enum ip_conntrack_info ctinfo;
struct nf_conntrack_l3proto *l3proto;
struct nf_conntrack_l4proto *l4proto;
@@ -764,10 +770,14 @@ nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
int set_reply = 0;
int ret;

- /* Previously seen (loopback or untracked)? Ignore. */
if (skb->nfct) {
- NF_CT_STAT_INC_ATOMIC(net, ignore);
- return NF_ACCEPT;
+ /* Previously seen (loopback or untracked)? Ignore. */
+ tmpl = (struct nf_conn *)skb->nfct;
+ if (!nf_ct_is_template(tmpl)) {
+ NF_CT_STAT_INC_ATOMIC(net, ignore);
+ return NF_ACCEPT;
+ }
+ skb->nfct = NULL;
}

/* rcu_read_lock()ed by nf_hook_slow */
@@ -778,7 +788,8 @@ nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
pr_debug("not prepared to track yet or error occured\n");
NF_CT_STAT_INC_ATOMIC(net, error);
NF_CT_STAT_INC_ATOMIC(net, invalid);
- return -ret;
+ ret = -ret;
+ goto out;
}

l4proto = __nf_ct_l4proto_find(pf, protonum);
@@ -791,22 +802,25 @@ nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
if (ret <= 0) {
NF_CT_STAT_INC_ATOMIC(net, error);
NF_CT_STAT_INC_ATOMIC(net, invalid);
- return -ret;
+ ret = -ret;
+ goto out;
}
}

- ct = resolve_normal_ct(net, skb, dataoff, pf, protonum,
+ ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum,
l3proto, l4proto, &set_reply, &ctinfo);
if (!ct) {
/* Not valid part of a connection */
NF_CT_STAT_INC_ATOMIC(net, invalid);
- return NF_ACCEPT;
+ ret = NF_ACCEPT;
+ goto out;
}

if (IS_ERR(ct)) {
/* Too stressed to deal. */
NF_CT_STAT_INC_ATOMIC(net, drop);
- return NF_DROP;
+ ret = NF_DROP;
+ goto out;
}

NF_CT_ASSERT(skb->nfct);
@@ -821,11 +835,15 @@ nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
NF_CT_STAT_INC_ATOMIC(net, invalid);
if (ret == -NF_DROP)
NF_CT_STAT_INC_ATOMIC(net, drop);
- return -ret;
+ ret = -ret;
+ goto out;
}

if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
nf_conntrack_event_cache(IPCT_REPLY, ct);
+out:
+ if (tmpl)
+ nf_ct_put(tmpl);

return ret;
}
@@ -864,7 +882,7 @@ void nf_conntrack_alter_reply(struct nf_conn *ct,
return;

rcu_read_lock();
- __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
+ __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
index c0e461f..8144b0d 100644
--- a/net/netfilter/nf_conntrack_helper.c
+++ b/net/netfilter/nf_conntrack_helper.c
@@ -96,13 +96,22 @@ struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp)
}
EXPORT_SYMBOL_GPL(nf_ct_helper_ext_add);

-int __nf_ct_try_assign_helper(struct nf_conn *ct, gfp_t flags)
+int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
+ gfp_t flags)
{
+ struct nf_conntrack_helper *helper = NULL;
+ struct nf_conn_help *help;
int ret = 0;
- struct nf_conntrack_helper *helper;
- struct nf_conn_help *help = nfct_help(ct);

- helper = __nf_ct_helper_find(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
+ if (tmpl != NULL) {
+ help = nfct_help(tmpl);
+ if (help != NULL)
+ helper = help->helper;
+ }
+
+ help = nfct_help(ct);
+ if (helper == NULL)
+ helper = __nf_ct_helper_find(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
if (helper == NULL) {
if (help)
rcu_assign_pointer(help->helper, NULL);
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index f5c0b09..09044f9 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1249,7 +1249,7 @@ ctnetlink_create_conntrack(struct net *net,
}
} else {
/* try an implicit helper assignation */
- err = __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
+ err = __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
if (err < 0)
goto err2;
}