diff options
Diffstat (limited to 'net/ipv6/netfilter/ip6t_multiport.c')
-rw-r--r-- | net/ipv6/netfilter/ip6t_multiport.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/net/ipv6/netfilter/ip6t_multiport.c b/net/ipv6/netfilter/ip6t_multiport.c new file mode 100644 index 000000000000..6e3246153fa3 --- /dev/null +++ b/net/ipv6/netfilter/ip6t_multiport.c @@ -0,0 +1,125 @@ +/* Kernel module to match one of a list of TCP/UDP ports: ports are in + the same place so we can treat them as equal. */ + +/* (C) 1999-2001 Paul `Rusty' Russell + * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/udp.h> +#include <linux/skbuff.h> +#include <linux/in.h> + +#include <linux/netfilter_ipv6/ip6t_multiport.h> +#include <linux/netfilter_ipv6/ip6_tables.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); +MODULE_DESCRIPTION("ip6tables match for multiple ports"); + +#if 0 +#define duprintf(format, args...) printk(format , ## args) +#else +#define duprintf(format, args...) +#endif + +/* Returns 1 if the port is matched by the test, 0 otherwise. */ +static inline int +ports_match(const u_int16_t *portlist, enum ip6t_multiport_flags flags, + u_int8_t count, u_int16_t src, u_int16_t dst) +{ + unsigned int i; + for (i=0; i<count; i++) { + if (flags != IP6T_MULTIPORT_DESTINATION + && portlist[i] == src) + return 1; + + if (flags != IP6T_MULTIPORT_SOURCE + && portlist[i] == dst) + return 1; + } + + return 0; +} + +static int +match(const struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + const void *matchinfo, + int offset, + unsigned int protoff, + int *hotdrop) +{ + u16 _ports[2], *pptr; + const struct ip6t_multiport *multiinfo = matchinfo; + + /* Must not be a fragment. */ + if (offset) + return 0; + + /* Must be big enough to read ports (both UDP and TCP have + them at the start). */ + pptr = skb_header_pointer(skb, protoff, sizeof(_ports), &_ports[0]); + if (pptr == NULL) { + /* We've been asked to examine this packet, and we + * can't. Hence, no choice but to drop. + */ + duprintf("ip6t_multiport:" + " Dropping evil offset=0 tinygram.\n"); + *hotdrop = 1; + return 0; + } + + return ports_match(multiinfo->ports, + multiinfo->flags, multiinfo->count, + ntohs(pptr[0]), ntohs(pptr[1])); +} + +/* Called when user tries to insert an entry of this type. */ +static int +checkentry(const char *tablename, + const struct ip6t_ip6 *ip, + void *matchinfo, + unsigned int matchsize, + unsigned int hook_mask) +{ + const struct ip6t_multiport *multiinfo = matchinfo; + + if (matchsize != IP6T_ALIGN(sizeof(struct ip6t_multiport))) + return 0; + + /* Must specify proto == TCP/UDP, no unknown flags or bad count */ + return (ip->proto == IPPROTO_TCP || ip->proto == IPPROTO_UDP) + && !(ip->invflags & IP6T_INV_PROTO) + && matchsize == IP6T_ALIGN(sizeof(struct ip6t_multiport)) + && (multiinfo->flags == IP6T_MULTIPORT_SOURCE + || multiinfo->flags == IP6T_MULTIPORT_DESTINATION + || multiinfo->flags == IP6T_MULTIPORT_EITHER) + && multiinfo->count <= IP6T_MULTI_PORTS; +} + +static struct ip6t_match multiport_match = { + .name = "multiport", + .match = &match, + .checkentry = &checkentry, + .me = THIS_MODULE, +}; + +static int __init init(void) +{ + return ip6t_register_match(&multiport_match); +} + +static void __exit fini(void) +{ + ip6t_unregister_match(&multiport_match); +} + +module_init(init); +module_exit(fini); |