Try to allocate a Netlink skb roughly the size of the actual
message, with the help from the l3 and l4 protocol helpers.
This is all to prevent a reallocation in netlink_trim() later.
The overhead of allocating the right-sized skb is rather small, with
ctnetlink_alloc_skb() actually being inlined away on my x86_64 box.
The size of the per-proto space is determined at registration time of
the protocol helper.
Signed-off-by: Holger Eitzenberger <holger@xxxxxxxxxxxxxxxx>
Index: nf-next-2.6/net/netfilter/nf_conntrack_netlink.c
===================================================================
--- nf-next-2.6.orig/net/netfilter/nf_conntrack_netlink.c
+++ nf-next-2.6/net/netfilter/nf_conntrack_netlink.c
@@ -404,6 +404,69 @@ nla_put_failure:
}
#ifdef CONFIG_NF_CONNTRACK_EVENTS
+/*
+ * The general structure of a ctnetlink event is
+ *
+ * CTA_TUPLE_ORIG
+ * <l3/l4-proto-attributes>
+ * CTA_TUPLE_REPLY
+ * <l3/l4-proto-attributes>
+ * CTA_ID
+ * ...
+ * CTA_PROTOINFO
+ * <l4-proto-attributes>
+ * CTA_TUPLE_MASTER
+ * <l3/l4-proto-attributes>
+ *
+ * Therefore the formular is
+ *
+ * size = sizeof(headers) + sizeof(generic_nlas) + 3 * sizeof(tuple_nlas)
+ * + sizeof(protoinfo_nlas)
+ */
+static struct sk_buff *
+ctnetlink_alloc_skb(const struct nf_conntrack_tuple *tuple, gfp_t gfp)
+{
+ struct nf_conntrack_l3proto *l3proto;
+ struct nf_conntrack_l4proto *l4proto;
+ int len;
+
+#define NLA_TYPE_SIZE(type) nla_total_size(sizeof(type))
+
+ /* proto independant part */
+ len = NLMSG_SPACE(sizeof(struct nfgenmsg))
+ + 3 * nla_total_size(0) /* CTA_TUPLE_ORIG|REPL|MASTER */
+ + 3 * nla_total_size(0) /* CTA_TUPLE_IP */
+ + 3 * nla_total_size(0) /* CTA_TUPLE_PROTO */
+ + 3 * NLA_TYPE_SIZE(u_int8_t) /* CTA_PROTO_NUM */
+ + NLA_TYPE_SIZE(u_int32_t) /* CTA_ID */
+ + NLA_TYPE_SIZE(u_int32_t) /* CTA_STATUS */
+ + 2 * nla_total_size(0) /* CTA_COUNTERS_ORIG|REPL */
+ + 2 * NLA_TYPE_SIZE(uint64_t) /* CTA_COUNTERS_PACKETS */
+ + 2 * NLA_TYPE_SIZE(uint64_t) /* CTA_COUNTERS_BYTES */
+ + NLA_TYPE_SIZE(u_int32_t) /* CTA_TIMEOUT */
+ + nla_total_size(0) /* CTA_PROTOINFO */
+ + nla_total_size(0) /* CTA_HELP */
+ + nla_total_size(NF_CT_HELPER_NAME_LEN) /* CTA_HELP_NAME */
+ + NLA_TYPE_SIZE(u_int32_t) /* CTA_SECMARK */
+ + 2 * nla_total_size(0) /* CTA_NAT_SEQ_ADJ_ORIG|REPL */
+ + 2 * NLA_TYPE_SIZE(u_int32_t) /* CTA_NAT_SEQ_CORRECTION_POS */
+ + 2 * NLA_TYPE_SIZE(u_int32_t) /* CTA_NAT_SEQ_CORRECTION_BEFORE */
+ + 2 * NLA_TYPE_SIZE(u_int32_t) /* CTA_NAT_SEQ_CORRECTION_AFTER */
+ + NLA_TYPE_SIZE(u_int32_t); /* CTA_MARK */
+
+#undef NLA_TYPE_SIZE
+
+ rcu_read_lock();
+ l3proto = __nf_ct_l3proto_find(tuple->src.l3num);
+ len += l3proto->nla_size;
+
+ l4proto = __nf_ct_l4proto_find(tuple->src.l3num, tuple->dst.protonum);
+ len += l4proto->nla_size;
+ rcu_read_unlock();
+
+ return alloc_skb(len, gfp);
+}
+
static int ctnetlink_conntrack_event(struct notifier_block *this,
unsigned long events, void *ptr)
{
@@ -437,7 +500,7 @@ static int ctnetlink_conntrack_event(str
if (!item->report && !nfnetlink_has_listeners(group))
return NOTIFY_DONE;
- skb = alloc_skb(NLMSG_GOODSIZE, GFP_ATOMIC);
+ skb = ctnetlink_alloc_skb(tuple(ct, IP_CT_DIR_ORIGINAL), GFP_ATOMIC);
if (!skb)
return NOTIFY_DONE;
--
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
