[NETFILTER]: nf_conntrack_netlink: add support to related connections
Pablo Neira Ayuso [Fri, 28 Sep 2007 21:43:53 +0000 (14:43 -0700)]
This patch adds support to relate a connection to an existing master
connection. This patch is used by conntrackd to correctly replicate
related connections.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter/nfnetlink_conntrack.h
net/netfilter/nf_conntrack_netlink.c

index d7c3503..4affa3f 100644 (file)
@@ -36,6 +36,7 @@ enum ctattr_type {
        CTA_USE,
        CTA_ID,
        CTA_NAT_DST,
+       CTA_TUPLE_MASTER,
        __CTA_MAX
 };
 #define CTA_MAX (__CTA_MAX - 1)
index 2abd648..9be1826 100644 (file)
@@ -4,7 +4,7 @@
  * (C) 2001 by Jay Schulist <jschlst@samba.org>
  * (C) 2002-2006 by Harald Welte <laforge@gnumonks.org>
  * (C) 2003 by Patrick Mchardy <kaber@trash.net>
- * (C) 2005-2006 by Pablo Neira Ayuso <pablo@eurodev.net>
+ * (C) 2005-2007 by Pablo Neira Ayuso <pablo@netfilter.org>
  *
  * Initial connection tracking via netlink development funded and
  * generally made possible by Network Robots, Inc. (www.networkrobots.com)
@@ -975,7 +975,8 @@ ctnetlink_change_conntrack(struct nf_conn *ct, struct nlattr *cda[])
 static int
 ctnetlink_create_conntrack(struct nlattr *cda[],
                           struct nf_conntrack_tuple *otuple,
-                          struct nf_conntrack_tuple *rtuple)
+                          struct nf_conntrack_tuple *rtuple,
+                          struct nf_conn *master_ct)
 {
        struct nf_conn *ct;
        int err = -EINVAL;
@@ -1022,6 +1023,10 @@ ctnetlink_create_conntrack(struct nlattr *cda[],
                rcu_assign_pointer(help->helper, helper);
        }
 
+       /* setup master conntrack: this is a confirmed expectation */
+       if (master_ct)
+               ct->master = master_ct;
+
        add_timer(&ct->timeout);
        nf_conntrack_hash_insert(ct);
 
@@ -1064,10 +1069,37 @@ ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
                h = __nf_conntrack_find(&rtuple, NULL);
 
        if (h == NULL) {
+               struct nf_conntrack_tuple master;
+               struct nf_conntrack_tuple_hash *master_h = NULL;
+               struct nf_conn *master_ct = NULL;
+
+               if (cda[CTA_TUPLE_MASTER]) {
+                       err = ctnetlink_parse_tuple(cda,
+                                                   &master,
+                                                   CTA_TUPLE_MASTER,
+                                                   u3);
+                       if (err < 0)
+                               return err;
+
+                       master_h = __nf_conntrack_find(&master, NULL);
+                       if (master_h == NULL) {
+                               err = -ENOENT;
+                               goto out_unlock;
+                       }
+                       master_ct = nf_ct_tuplehash_to_ctrack(master_h);
+                       atomic_inc(&master_ct->ct_general.use);
+               }
+
                write_unlock_bh(&nf_conntrack_lock);
                err = -ENOENT;
                if (nlh->nlmsg_flags & NLM_F_CREATE)
-                       err = ctnetlink_create_conntrack(cda, &otuple, &rtuple);
+                       err = ctnetlink_create_conntrack(cda,
+                                                        &otuple,
+                                                        &rtuple,
+                                                        master_ct);
+               if (err < 0 && master_ct)
+                       nf_ct_put(master_ct);
+
                return err;
        }
        /* implicit 'else' */
@@ -1081,6 +1113,11 @@ ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
                        err = -EINVAL;
                        goto out_unlock;
                }
+               /* can't link an existing conntrack to a master */
+               if (cda[CTA_TUPLE_MASTER]) {
+                       err = -EINVAL;
+                       goto out_unlock;
+               }
                err = ctnetlink_change_conntrack(nf_ct_tuplehash_to_ctrack(h),
                                                 cda);
        }