2ae15b64e6
Updates the MODULE_DESCRIPTION() tags for all Netfilter modules, actually describing what the module does and not just "netfilter XYZ target". Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
106 lines
2.6 KiB
C
106 lines
2.6 KiB
C
/* Kernel module to match AH parameters. */
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/* (C) 1999-2000 Yon Uriarte <yon@astaro.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/in.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/ip.h>
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#include <linux/netfilter_ipv4/ipt_ah.h>
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#include <linux/netfilter/x_tables.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>");
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MODULE_DESCRIPTION("Xtables: IPv4 IPsec-AH SPI match");
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#ifdef DEBUG_CONNTRACK
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#define duprintf(format, args...) printk(format , ## args)
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#else
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#define duprintf(format, args...)
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#endif
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/* Returns 1 if the spi is matched by the range, 0 otherwise */
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static inline bool
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spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert)
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{
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bool r;
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duprintf("ah spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
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min,spi,max);
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r=(spi >= min && spi <= max) ^ invert;
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duprintf(" result %s\n",r? "PASS" : "FAILED");
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return r;
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}
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static bool
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ah_mt(const struct sk_buff *skb, const struct net_device *in,
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const struct net_device *out, const struct xt_match *match,
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const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop)
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{
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struct ip_auth_hdr _ahdr;
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const struct ip_auth_hdr *ah;
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const struct ipt_ah *ahinfo = matchinfo;
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/* Must not be a fragment. */
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if (offset)
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return false;
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ah = skb_header_pointer(skb, protoff,
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sizeof(_ahdr), &_ahdr);
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if (ah == NULL) {
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/* We've been asked to examine this packet, and we
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* can't. Hence, no choice but to drop.
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*/
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duprintf("Dropping evil AH tinygram.\n");
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*hotdrop = true;
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return 0;
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}
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return spi_match(ahinfo->spis[0], ahinfo->spis[1],
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ntohl(ah->spi),
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!!(ahinfo->invflags & IPT_AH_INV_SPI));
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}
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/* Called when user tries to insert an entry of this type. */
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static bool
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ah_mt_check(const char *tablename, const void *ip_void,
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const struct xt_match *match, void *matchinfo,
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unsigned int hook_mask)
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{
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const struct ipt_ah *ahinfo = matchinfo;
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/* Must specify no unknown invflags */
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if (ahinfo->invflags & ~IPT_AH_INV_MASK) {
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duprintf("ipt_ah: unknown flags %X\n", ahinfo->invflags);
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return false;
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}
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return true;
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}
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static struct xt_match ah_mt_reg __read_mostly = {
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.name = "ah",
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.family = AF_INET,
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.match = ah_mt,
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.matchsize = sizeof(struct ipt_ah),
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.proto = IPPROTO_AH,
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.checkentry = ah_mt_check,
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.me = THIS_MODULE,
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};
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static int __init ah_mt_init(void)
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{
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return xt_register_match(&ah_mt_reg);
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}
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static void __exit ah_mt_exit(void)
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{
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xt_unregister_match(&ah_mt_reg);
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}
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module_init(ah_mt_init);
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module_exit(ah_mt_exit);
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