diff options
Diffstat (limited to 'net/ipv4/netfilter/ipt_multiport.c')
| -rw-r--r-- | net/ipv4/netfilter/ipt_multiport.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ipt_multiport.c b/net/ipv4/netfilter/ipt_multiport.c new file mode 100644 index 00000000000..99e8188162e --- /dev/null +++ b/net/ipv4/netfilter/ipt_multiport.c @@ -0,0 +1,212 @@ +/* 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/netfilter_ipv4/ipt_multiport.h> +#include <linux/netfilter_ipv4/ip_tables.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); +MODULE_DESCRIPTION("iptables multiple port match module"); + +#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 ipt_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 != IPT_MULTIPORT_DESTINATION + && portlist[i] == src) + return 1; + + if (flags != IPT_MULTIPORT_SOURCE + && portlist[i] == dst) + return 1; + } + + return 0; +} + +/* Returns 1 if the port is matched by the test, 0 otherwise. */ +static inline int +ports_match_v1(const struct ipt_multiport_v1 *minfo, + u_int16_t src, u_int16_t dst) +{ + unsigned int i; + u_int16_t s, e; + + for (i=0; i < minfo->count; i++) { + s = minfo->ports[i]; + + if (minfo->pflags[i]) { + /* range port matching */ + e = minfo->ports[++i]; + duprintf("src or dst matches with %d-%d?\n", s, e); + + if (minfo->flags == IPT_MULTIPORT_SOURCE + && src >= s && src <= e) + return 1 ^ minfo->invert; + if (minfo->flags == IPT_MULTIPORT_DESTINATION + && dst >= s && dst <= e) + return 1 ^ minfo->invert; + if (minfo->flags == IPT_MULTIPORT_EITHER + && ((dst >= s && dst <= e) + || (src >= s && src <= e))) + return 1 ^ minfo->invert; + } else { + /* exact port matching */ + duprintf("src or dst matches with %d?\n", s); + + if (minfo->flags == IPT_MULTIPORT_SOURCE + && src == s) + return 1 ^ minfo->invert; + if (minfo->flags == IPT_MULTIPORT_DESTINATION + && dst == s) + return 1 ^ minfo->invert; + if (minfo->flags == IPT_MULTIPORT_EITHER + && (src == s || dst == s)) + return 1 ^ minfo->invert; + } + } + + return minfo->invert; +} + +static int +match(const struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + const void *matchinfo, + int offset, + int *hotdrop) +{ + u16 _ports[2], *pptr; + const struct ipt_multiport *multiinfo = matchinfo; + + if (offset) + return 0; + + pptr = skb_header_pointer(skb, skb->nh.iph->ihl * 4, + sizeof(_ports), _ports); + if (pptr == NULL) { + /* We've been asked to examine this packet, and we + * can't. Hence, no choice but to drop. + */ + duprintf("ipt_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])); +} + +static int +match_v1(const struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + const void *matchinfo, + int offset, + int *hotdrop) +{ + u16 _ports[2], *pptr; + const struct ipt_multiport_v1 *multiinfo = matchinfo; + + if (offset) + return 0; + + pptr = skb_header_pointer(skb, skb->nh.iph->ihl * 4, + sizeof(_ports), _ports); + if (pptr == NULL) { + /* We've been asked to examine this packet, and we + * can't. Hence, no choice but to drop. + */ + duprintf("ipt_multiport:" + " Dropping evil offset=0 tinygram.\n"); + *hotdrop = 1; + return 0; + } + + return ports_match_v1(multiinfo, 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 ipt_ip *ip, + void *matchinfo, + unsigned int matchsize, + unsigned int hook_mask) +{ + return (matchsize == IPT_ALIGN(sizeof(struct ipt_multiport))); +} + +static int +checkentry_v1(const char *tablename, + const struct ipt_ip *ip, + void *matchinfo, + unsigned int matchsize, + unsigned int hook_mask) +{ + return (matchsize == IPT_ALIGN(sizeof(struct ipt_multiport_v1))); +} + +static struct ipt_match multiport_match = { + .name = "multiport", + .revision = 0, + .match = &match, + .checkentry = &checkentry, + .me = THIS_MODULE, +}; + +static struct ipt_match multiport_match_v1 = { + .name = "multiport", + .revision = 1, + .match = &match_v1, + .checkentry = &checkentry_v1, + .me = THIS_MODULE, +}; + +static int __init init(void) +{ + int err; + + err = ipt_register_match(&multiport_match); + if (!err) { + err = ipt_register_match(&multiport_match_v1); + if (err) + ipt_unregister_match(&multiport_match); + } + + return err; +} + +static void __exit fini(void) +{ + ipt_unregister_match(&multiport_match); + ipt_unregister_match(&multiport_match_v1); +} + +module_init(init); +module_exit(fini); |