netfilter: nfnetlink_acct: add filter support to nfacct counter list/reset

You can use this to skip accounting objects when listing/resetting
via NFNL_MSG_ACCT_GET/NFNL_MSG_ACCT_GET_CTRZERO messages with the
NLM_F_DUMP netlink flag. The filtering covers the following cases:

1. No filter specified. In this case, the client will get old behaviour,
2. List/reset counter object only: In this case, you have to use
   NFACCT_F_QUOTA as mask and value 0.
3. List/reset quota objects only: You have to use NFACCT_F_QUOTA_PKTS
   as mask and value - the same, for byte based quota mask should be
   NFACCT_F_QUOTA_BYTES and value - the same.

If you want to obtain the object with any quota type
(ie. NFACCT_F_QUOTA_PKTS|NFACCT_F_QUOTA_BYTES), you need to perform
two dump requests, one to obtain NFACCT_F_QUOTA_PKTS objects and
another for NFACCT_F_QUOTA_BYTES.

Signed-off-by: Alexey Perevalov <a.perevalov@samsung.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/include/uapi/linux/netfilter/nfnetlink_acct.h b/include/uapi/linux/netfilter/nfnetlink_acct.h
index 51404ec..f3e34db 100644 (file)
--- a/include/uapi/linux/netfilter/nfnetlink_acct.h
+++ b/include/uapi/linux/netfilter/nfnetlink_acct.h
@@ -28,9 +28,17 @@ enum nfnl_acct_type {
        NFACCT_USE,
        NFACCT_FLAGS,
        NFACCT_QUOTA,
+       NFACCT_FILTER,
        __NFACCT_MAX
 };
 #define NFACCT_MAX (__NFACCT_MAX - 1)
 
+enum nfnl_attr_filter_type {
+       NFACCT_FILTER_UNSPEC,
+       NFACCT_FILTER_MASK,
+       NFACCT_FILTER_VALUE,
+       __NFACCT_FILTER_MAX
+};
+#define NFACCT_FILTER_MAX (__NFACCT_FILTER_MAX - 1)
 
 #endif /* _UAPI_NFNL_ACCT_H_ */

diff --git a/net/netfilter/nfnetlink_acct.c b/net/netfilter/nfnetlink_acct.c
index 3ea0eac..c18af2f 100644 (file)
--- a/net/netfilter/nfnetlink_acct.c
+++ b/net/netfilter/nfnetlink_acct.c
@@ -40,6 +40,11 @@ struct nf_acct {
        char                    data[0];
 };
 
+struct nfacct_filter {
+       u32 value;
+       u32 mask;
+};
+
 #define NFACCT_F_QUOTA (NFACCT_F_QUOTA_PKTS | NFACCT_F_QUOTA_BYTES)
 #define NFACCT_OVERQUOTA_BIT   2       /* NFACCT_F_OVERQUOTA */
 
@@ -181,6 +186,7 @@ static int
 nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb)
 {
        struct nf_acct *cur, *last;
+       const struct nfacct_filter *filter = cb->data;
 
        if (cb->args[2])
                return 0;
@@ -197,6 +203,10 @@ nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb)
 
                        last = NULL;
                }
+
+               if (filter && (cur->flags & filter->mask) != filter->value)
+                       continue;
+
                if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).portid,
                                       cb->nlh->nlmsg_seq,
                                       NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
@@ -211,6 +221,38 @@ nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb)
        return skb->len;
 }
 
+static int nfnl_acct_done(struct netlink_callback *cb)
+{
+       kfree(cb->data);
+       return 0;
+}
+
+static const struct nla_policy filter_policy[NFACCT_FILTER_MAX + 1] = {
+       [NFACCT_FILTER_MASK]    = { .type = NLA_U32 },
+       [NFACCT_FILTER_VALUE]   = { .type = NLA_U32 },
+};
+
+static struct nfacct_filter *
+nfacct_filter_alloc(const struct nlattr * const attr)
+{
+       struct nfacct_filter *filter;
+       struct nlattr *tb[NFACCT_FILTER_MAX + 1];
+       int err;
+
+       err = nla_parse_nested(tb, NFACCT_FILTER_MAX, attr, filter_policy);
+       if (err < 0)
+               return ERR_PTR(err);
+
+       filter = kzalloc(sizeof(struct nfacct_filter), GFP_KERNEL);
+       if (!filter)
+               return ERR_PTR(-ENOMEM);
+
+       filter->mask = ntohl(nla_get_be32(tb[NFACCT_FILTER_MASK]));
+       filter->value = ntohl(nla_get_be32(tb[NFACCT_FILTER_VALUE]));
+
+       return filter;
+}
+
 static int
 nfnl_acct_get(struct sock *nfnl, struct sk_buff *skb,
             const struct nlmsghdr *nlh, const struct nlattr * const tb[])
@@ -222,7 +264,18 @@ nfnl_acct_get(struct sock *nfnl, struct sk_buff *skb,
        if (nlh->nlmsg_flags & NLM_F_DUMP) {
                struct netlink_dump_control c = {
                        .dump = nfnl_acct_dump,
+                       .done = nfnl_acct_done,
                };
+
+               if (tb[NFACCT_FILTER]) {
+                       struct nfacct_filter *filter;
+
+                       filter = nfacct_filter_alloc(tb[NFACCT_FILTER]);
+                       if (IS_ERR(filter))
+                               return PTR_ERR(filter);
+
+                       c.data = filter;
+               }
                return netlink_dump_start(nfnl, skb, nlh, &c);
        }
 
@@ -314,6 +367,7 @@ static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = {
        [NFACCT_PKTS] = { .type = NLA_U64 },
        [NFACCT_FLAGS] = { .type = NLA_U32 },
        [NFACCT_QUOTA] = { .type = NLA_U64 },
+       [NFACCT_FILTER] = {.type = NLA_NESTED },
 };
 
 static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = {