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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 | /* Kernel module to match AH parameters. */ /* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu> * * 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/skbuff.h> #include <linux/ip.h> #include <linux/ipv6.h> #include <linux/types.h> #include <net/checksum.h> #include <net/ipv6.h> #include <linux/netfilter_ipv6/ip6_tables.h> #include <linux/netfilter_ipv6/ip6t_ah.h> MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("IPv6 AH match"); MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>"); #if 0 #define DEBUGP printk #else #define DEBUGP(format, args...) #endif /* Returns 1 if the spi is matched by the range, 0 otherwise */ static inline int spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert) { int r=0; DEBUGP("ah spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ', min,spi,max); r = (spi >= min && spi <= max) ^ invert; DEBUGP(" result %s\n",r? "PASS\n" : "FAILED\n"); return r; } 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) { struct ip_auth_hdr *ah, _ah; const struct ip6t_ah *ahinfo = matchinfo; unsigned int ptr; unsigned int hdrlen = 0; if (ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL) < 0) return 0; ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah); if (ah == NULL) { *hotdrop = 1; return 0; } hdrlen = (ah->hdrlen + 2) << 2; DEBUGP("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen); DEBUGP("RES %04X ", ah->reserved); DEBUGP("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi)); DEBUGP("IPv6 AH spi %02X ", (spi_match(ahinfo->spis[0], ahinfo->spis[1], ntohl(ah->spi), !!(ahinfo->invflags & IP6T_AH_INV_SPI)))); DEBUGP("len %02X %04X %02X ", ahinfo->hdrlen, hdrlen, (!ahinfo->hdrlen || (ahinfo->hdrlen == hdrlen) ^ !!(ahinfo->invflags & IP6T_AH_INV_LEN))); DEBUGP("res %02X %04X %02X\n", ahinfo->hdrres, ah->reserved, !(ahinfo->hdrres && ah->reserved)); return (ah != NULL) && (spi_match(ahinfo->spis[0], ahinfo->spis[1], ntohl(ah->spi), !!(ahinfo->invflags & IP6T_AH_INV_SPI))) && (!ahinfo->hdrlen || (ahinfo->hdrlen == hdrlen) ^ !!(ahinfo->invflags & IP6T_AH_INV_LEN)) && !(ahinfo->hdrres && ah->reserved); } /* Called when user tries to insert an entry of this type. */ static int checkentry(const char *tablename, const void *entry, void *matchinfo, unsigned int matchinfosize, unsigned int hook_mask) { const struct ip6t_ah *ahinfo = matchinfo; if (matchinfosize != IP6T_ALIGN(sizeof(struct ip6t_ah))) { DEBUGP("ip6t_ah: matchsize %u != %u\n", matchinfosize, IP6T_ALIGN(sizeof(struct ip6t_ah))); return 0; } if (ahinfo->invflags & ~IP6T_AH_INV_MASK) { DEBUGP("ip6t_ah: unknown flags %X\n", ahinfo->invflags); return 0; } return 1; } static struct ip6t_match ah_match = { .name = "ah", .match = &match, .checkentry = &checkentry, .me = THIS_MODULE, }; static int __init init(void) { return ip6t_register_match(&ah_match); } static void __exit cleanup(void) { ip6t_unregister_match(&ah_match); } module_init(init); module_exit(cleanup); |