diff options
Diffstat (limited to 'net/netfilter/nf_conntrack_netbios_ns.c')
-rw-r--r-- | net/netfilter/nf_conntrack_netbios_ns.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/net/netfilter/nf_conntrack_netbios_ns.c b/net/netfilter/nf_conntrack_netbios_ns.c new file mode 100644 index 0000000000..55415f0119 --- /dev/null +++ b/net/netfilter/nf_conntrack_netbios_ns.c @@ -0,0 +1,71 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * NetBIOS name service broadcast connection tracking helper + * + * (c) 2005 Patrick McHardy <kaber@trash.net> + */ +/* + * This helper tracks locally originating NetBIOS name service + * requests by issuing permanent expectations (valid until + * timing out) matching all reply connections from the + * destination network. The only NetBIOS specific thing is + * actually the port number. + */ +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/in.h> + +#include <net/netfilter/nf_conntrack.h> +#include <net/netfilter/nf_conntrack_helper.h> +#include <net/netfilter/nf_conntrack_expect.h> + +#define HELPER_NAME "netbios-ns" +#define NMBD_PORT 137 + +MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); +MODULE_DESCRIPTION("NetBIOS name service broadcast connection tracking helper"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("ip_conntrack_netbios_ns"); +MODULE_ALIAS_NFCT_HELPER(HELPER_NAME); + +static unsigned int timeout __read_mostly = 3; +module_param(timeout, uint, 0400); +MODULE_PARM_DESC(timeout, "timeout for master connection/replies in seconds"); + +static struct nf_conntrack_expect_policy exp_policy = { + .max_expected = 1, +}; + +static int netbios_ns_help(struct sk_buff *skb, unsigned int protoff, + struct nf_conn *ct, + enum ip_conntrack_info ctinfo) +{ + return nf_conntrack_broadcast_help(skb, ct, ctinfo, timeout); +} + +static struct nf_conntrack_helper helper __read_mostly = { + .name = HELPER_NAME, + .tuple.src.l3num = NFPROTO_IPV4, + .tuple.src.u.udp.port = cpu_to_be16(NMBD_PORT), + .tuple.dst.protonum = IPPROTO_UDP, + .me = THIS_MODULE, + .help = netbios_ns_help, + .expect_policy = &exp_policy, +}; + +static int __init nf_conntrack_netbios_ns_init(void) +{ + NF_CT_HELPER_BUILD_BUG_ON(0); + + exp_policy.timeout = timeout; + return nf_conntrack_helper_register(&helper); +} + +static void __exit nf_conntrack_netbios_ns_fini(void) +{ + nf_conntrack_helper_unregister(&helper); +} + +module_init(nf_conntrack_netbios_ns_init); +module_exit(nf_conntrack_netbios_ns_fini); |