netfilter: nf_conntrack: support conntrack templates
Patrick McHardy [Wed, 3 Feb 2010 13:13:03 +0000 (14:13 +0100)]
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>

include/linux/netfilter/nf_conntrack_common.h
include/net/netfilter/nf_conntrack.h
include/net/netfilter/nf_conntrack_helper.h
net/ipv4/netfilter/nf_defrag_ipv4.c
net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
net/netfilter/nf_conntrack_core.c
net/netfilter/nf_conntrack_helper.c
net/netfilter/nf_conntrack_netlink.c

index ebfed90..c608677 100644 (file)
@@ -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 */
index a0904ad..5043d61 100644 (file)
@@ -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)
 {
index 86be7c4..e17aaa3 100644 (file)
@@ -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);
 
index 331ead3..77627fa 100644 (file)
@@ -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
index 0956eba..55ce22e 100644 (file)
@@ -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));
index 53b8da6..471e2a7 100644 (file)
@@ -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);
index c0e461f..8144b0d 100644 (file)
@@ -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);
index f5c0b09..09044f9 100644 (file)
@@ -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;
        }