netfilter: nfnetlink_log: allow to attach conntrack

This patch enables to include the conntrack information together
with the packet that is sent to user-space via NFLOG, then a
user-space program can acquire NATed information by this NFULA_CT
attribute.

Including the conntrack information is optional, you can set it
via NFULNL_CFG_F_CONNTRACK flag with the NFULA_CFG_FLAGS attribute
like NFQUEUE.

Signed-off-by: Ken-ichirou MATSUZAWA <chamas@h4.dion.ne.jp>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/include/uapi/linux/netfilter/nfnetlink_log.h b/include/uapi/linux/netfilter/nfnetlink_log.h
index 90c2c95..fb21f0c 100644 (file)
--- a/include/uapi/linux/netfilter/nfnetlink_log.h
+++ b/include/uapi/linux/netfilter/nfnetlink_log.h
@@ -51,6 +51,8 @@ enum nfulnl_attr_type {
        NFULA_HWTYPE,                   /* hardware type */
        NFULA_HWHEADER,                 /* hardware header */
        NFULA_HWLEN,                    /* hardware header length */
+       NFULA_CT,                       /* nf_conntrack_netlink.h */
+       NFULA_CT_INFO,                  /* enum ip_conntrack_info */
 
        __NFULA_MAX
 };
@@ -93,5 +95,6 @@ enum nfulnl_attr_config {
 
 #define NFULNL_CFG_F_SEQ       0x0001
 #define NFULNL_CFG_F_SEQ_GLOBAL        0x0002
+#define NFULNL_CFG_F_CONNTRACK 0x0004
 
 #endif /* _NFNETLINK_LOG_H */

diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index d287818..e22349e 100644 (file)
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -363,12 +363,13 @@ config NF_CT_NETLINK_HELPER
          If unsure, say `N'.
 
 config NETFILTER_NETLINK_GLUE_CT
-       bool "NFQUEUE integration with Connection Tracking"
+       bool "NFQUEUE and NFLOG integration with Connection Tracking"
        default n
-       depends on NETFILTER_NETLINK_QUEUE && NF_CT_NETLINK
+       depends on (NETFILTER_NETLINK_QUEUE || NETFILTER_NETLINK_LOG) && NF_CT_NETLINK
        help
-         If this option is enabled, NFQUEUE can include Connection Tracking
-         information together with the packet is the enqueued via NFNETLINK.
+         If this option is enabled, NFQUEUE and NFLOG can include
+         Connection Tracking information together with the packet is
+         the enqueued via NFNETLINK.
 
 config NF_NAT
        tristate

diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index 4670821..e1d1187 100644 (file)
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -27,6 +27,7 @@
 #include <net/netlink.h>
 #include <linux/netfilter/nfnetlink.h>
 #include <linux/netfilter/nfnetlink_log.h>
+#include <linux/netfilter/nf_conntrack_common.h>
 #include <linux/spinlock.h>
 #include <linux/sysctl.h>
 #include <linux/proc_fs.h>
@@ -401,7 +402,9 @@ __build_packet_message(struct nfnl_log_net *log,
                        unsigned int hooknum,
                        const struct net_device *indev,
                        const struct net_device *outdev,
-                       const char *prefix, unsigned int plen)
+                       const char *prefix, unsigned int plen,
+                       const struct nfnl_ct_hook *nfnl_ct,
+                       struct nf_conn *ct, enum ip_conntrack_info ctinfo)
 {
        struct nfulnl_msg_packet_hdr pmsg;
        struct nlmsghdr *nlh;
@@ -575,6 +578,10 @@ __build_packet_message(struct nfnl_log_net *log,
                         htonl(atomic_inc_return(&log->global_seq))))
                goto nla_put_failure;
 
+       if (ct && nfnl_ct->build(inst->skb, ct, ctinfo,
+                                NFULA_CT, NFULA_CT_INFO) < 0)
+               goto nla_put_failure;
+
        if (data_len) {
                struct nlattr *nla;
                int size = nla_attr_size(data_len);
@@ -620,12 +627,16 @@ nfulnl_log_packet(struct net *net,
                  const struct nf_loginfo *li_user,
                  const char *prefix)
 {
-       unsigned int size, data_len;
+       size_t size;
+       unsigned int data_len;
        struct nfulnl_instance *inst;
        const struct nf_loginfo *li;
        unsigned int qthreshold;
        unsigned int plen;
        struct nfnl_log_net *log = nfnl_log_pernet(net);
+       const struct nfnl_ct_hook *nfnl_ct = NULL;
+       struct nf_conn *ct = NULL;
+       enum ip_conntrack_info uninitialized_var(ctinfo);
 
        if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
                li = li_user;
@@ -671,6 +682,14 @@ nfulnl_log_packet(struct net *net,
                size += nla_total_size(sizeof(u_int32_t));
        if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
                size += nla_total_size(sizeof(u_int32_t));
+       if (inst->flags & NFULNL_CFG_F_CONNTRACK) {
+               nfnl_ct = rcu_dereference(nfnl_ct_hook);
+               if (nfnl_ct != NULL) {
+                       ct = nfnl_ct->get_ct(skb, &ctinfo);
+                       if (ct != NULL)
+                               size += nfnl_ct->build_size(ct);
+               }
+       }
 
        qthreshold = inst->qthreshold;
        /* per-rule qthreshold overrides per-instance */
@@ -715,7 +734,8 @@ nfulnl_log_packet(struct net *net,
        inst->qlen++;
 
        __build_packet_message(log, inst, skb, data_len, pf,
-                               hooknum, in, out, prefix, plen);
+                               hooknum, in, out, prefix, plen,
+                               nfnl_ct, ct, ctinfo);
 
        if (inst->qlen >= qthreshold)
                __nfulnl_flush(inst);
@@ -899,13 +919,20 @@ nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
        }
 
        if (nfula[NFULA_CFG_FLAGS]) {
-               __be16 flags = nla_get_be16(nfula[NFULA_CFG_FLAGS]);
+               u16 flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS]));
 
                if (!inst) {
                        ret = -ENODEV;
                        goto out;
                }
-               nfulnl_set_flags(inst, ntohs(flags));
+
+               if (flags & NFULNL_CFG_F_CONNTRACK &&
+                   rcu_access_pointer(nfnl_ct_hook) == NULL) {
+                       ret = -EOPNOTSUPP;
+                       goto out;
+               }
+
+               nfulnl_set_flags(inst, flags);
        }
 
 out_put: