netfilter: ctnetlink: group errors into logical errno sets

This patch groups ctnetlink errors into three logical sets:

* Malformed messages: if ctnetlink receives a message without some mandatory
attribute, then it returns EINVAL.
* Unsupported operations: if userspace tries to perform an unsupported
operation, then it returns EOPNOTSUPP.
* Unchangeable: if userspace tries to change some attribute of the
conntrack object that can only be set once, then it returns EBUSY.

This patch reduces the number of -EINVAL from 23 to 14 and it results in
5 -EBUSY and 6 -EOPNOTSUPP.

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>

1 files changed, 10 insertions, 11 deletions

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 0edefcfc5949..13918c1fbf66 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -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) 2005-2007 by Pablo Neira Ayuso <pablo@netfilter.org>
+ * (C) 2005-2008 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)
@@ -891,20 +891,19 @@ ctnetlink_change_status(struct nf_conn *ct, struct nlattr *cda[])
 
         if (d & (IPS_EXPECTED|IPS_CONFIRMED|IPS_DYING))
                 /* unchangeable */
-                return -EINVAL;
+                return -EBUSY;
 
         if (d & IPS_SEEN_REPLY && !(status & IPS_SEEN_REPLY))
                 /* SEEN_REPLY bit can only be set */
-                return -EINVAL;
-
+                return -EBUSY;
 
         if (d & IPS_ASSURED && !(status & IPS_ASSURED))
                 /* ASSURED bit can only be set */
-                return -EINVAL;
+                return -EBUSY;
 
         if (cda[CTA_NAT_SRC] || cda[CTA_NAT_DST]) {
 #ifndef CONFIG_NF_NAT_NEEDED
-                return -EINVAL;
+                return -EOPNOTSUPP;
 #else
                 struct nf_nat_range range;
 
@@ -945,7 +944,7 @@ ctnetlink_change_helper(struct nf_conn *ct, struct nlattr *cda[])
 
         /* don't change helper of sibling connections */
         if (ct->master)
-                return -EINVAL;
+                return -EBUSY;
 
         err = ctnetlink_parse_help(cda[CTA_HELP], &helpname);
         if (err < 0)
@@ -963,7 +962,7 @@ ctnetlink_change_helper(struct nf_conn *ct, struct nlattr *cda[])
 
         helper = __nf_conntrack_helper_find_byname(helpname);
         if (helper == NULL)
-                return -EINVAL;
+                return -EOPNOTSUPP;
 
         if (help) {
                 if (help->helper == helper)
@@ -1258,12 +1257,12 @@ ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
         if (!(nlh->nlmsg_flags & NLM_F_EXCL)) {
                 /* we only allow nat config for new conntracks */
                 if (cda[CTA_NAT_SRC] || cda[CTA_NAT_DST]) {
-                        err = -EINVAL;
+                        err = -EOPNOTSUPP;
                         goto out_unlock;
                 }
                 /* can't link an existing conntrack to a master */
                 if (cda[CTA_TUPLE_MASTER]) {
-                        err = -EINVAL;
+                        err = -EOPNOTSUPP;
                         goto out_unlock;
                 }
                 err = ctnetlink_change_conntrack(nf_ct_tuplehash_to_ctrack(h),
@@ -1608,7 +1607,7 @@ ctnetlink_del_expect(struct sock *ctnl, struct sk_buff *skb,
                 h = __nf_conntrack_helper_find_byname(name);
                 if (!h) {
                         spin_unlock_bh(&nf_conntrack_lock);
-                        return -EINVAL;
+                        return -EOPNOTSUPP;
                 }
                 for (i = 0; i < nf_ct_expect_hsize; i++) {
                         hlist_for_each_entry_safe(exp, n, next,