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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 | /* * IPv6 packet mangling table, a port of the IPv4 mangle table to IPv6 * * Copyright (C) 2000 by Harald Welte <laforge@gnumonks.org> */ #include <linux/module.h> #include <linux/netfilter_ipv6/ip6_tables.h> #define MANGLE_VALID_HOOKS ((1 << NF_IP6_PRE_ROUTING) | (1 << NF_IP6_LOCAL_OUT)) #if 1 #define DEBUGP(x, args...) printk(KERN_DEBUG x, ## args) #else #define DEBUGP(x, args...) #endif /* Standard entry. */ struct ip6t_standard { struct ip6t_entry entry; struct ip6t_standard_target target; }; struct ip6t_error_target { struct ip6t_entry_target target; char errorname[IP6T_FUNCTION_MAXNAMELEN]; }; struct ip6t_error { struct ip6t_entry entry; struct ip6t_error_target target; }; static struct { struct ip6t_replace repl; struct ip6t_standard entries[2]; struct ip6t_error term; } initial_table __initdata = { { "mangle", MANGLE_VALID_HOOKS, 3, sizeof(struct ip6t_standard) * 2 + sizeof(struct ip6t_error), { [NF_IP6_PRE_ROUTING] 0, [NF_IP6_LOCAL_OUT] sizeof(struct ip6t_standard) }, { [NF_IP6_PRE_ROUTING] 0, [NF_IP6_LOCAL_OUT] sizeof(struct ip6t_standard) }, 0, NULL, { } }, { /* PRE_ROUTING */ { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 }, 0, sizeof(struct ip6t_entry), sizeof(struct ip6t_standard), 0, { 0, 0 }, { } }, { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } }, -NF_ACCEPT - 1 } }, /* LOCAL_OUT */ { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 }, 0, sizeof(struct ip6t_entry), sizeof(struct ip6t_standard), 0, { 0, 0 }, { } }, { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } }, -NF_ACCEPT - 1 } } }, /* ERROR */ { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 }, 0, sizeof(struct ip6t_entry), sizeof(struct ip6t_error), 0, { 0, 0 }, { } }, { { { { IP6T_ALIGN(sizeof(struct ip6t_error_target)), IP6T_ERROR_TARGET } }, { } }, "ERROR" } } }; static struct ip6t_table packet_mangler = { { NULL, NULL }, "mangle", &initial_table.repl, MANGLE_VALID_HOOKS, RW_LOCK_UNLOCKED, NULL }; /* The work comes in here from netfilter.c. */ static unsigned int ip6t_hook(unsigned int hook, struct sk_buff **pskb, const struct net_device *in, const struct net_device *out, int (*okfn)(struct sk_buff *)) { return ip6t_do_table(pskb, hook, in, out, &packet_mangler, NULL); } static unsigned int ip6t_local_out_hook(unsigned int hook, struct sk_buff **pskb, const struct net_device *in, const struct net_device *out, int (*okfn)(struct sk_buff *)) { unsigned long nfmark; unsigned int ret; struct in6_addr saddr, daddr; u_int8_t hop_limit; u_int32_t flowlabel; #if 0 /* root is playing with raw sockets. */ if ((*pskb)->len < sizeof(struct iphdr) || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr)) { if (net_ratelimit()) printk("ip6t_hook: happy cracking.\n"); return NF_ACCEPT; } #endif /* save source/dest address, nfmark, hoplimit, flowlabel, priority, */ memcpy(&saddr, &(*pskb)->nh.ipv6h->saddr, sizeof(saddr)); memcpy(&daddr, &(*pskb)->nh.ipv6h->daddr, sizeof(daddr)); nfmark = (*pskb)->nfmark; hop_limit = (*pskb)->nh.ipv6h->hop_limit; /* flowlabel and prio (includes version, which shouldn't change either */ flowlabel = (u_int32_t) (*pskb)->nh.ipv6h; ret = ip6t_do_table(pskb, hook, in, out, &packet_mangler, NULL); if (ret != NF_DROP && ret != NF_STOLEN && (memcmp(&(*pskb)->nh.ipv6h->saddr, &saddr, sizeof(saddr)) || memcmp(&(*pskb)->nh.ipv6h->daddr, &daddr, sizeof(daddr)) || (*pskb)->nfmark != nfmark || (*pskb)->nh.ipv6h->hop_limit != hop_limit)) { /* something which could affect routing has changed */ DEBUGP("ip6table_mangle: we'd need to re-route a packet\n"); } return ret; } static struct nf_hook_ops ip6t_ops[] = { { { NULL, NULL }, ip6t_hook, PF_INET6, NF_IP6_PRE_ROUTING, NF_IP6_PRI_MANGLE }, { { NULL, NULL }, ip6t_local_out_hook, PF_INET6, NF_IP6_LOCAL_OUT, NF_IP6_PRI_MANGLE } }; static int __init init(void) { int ret; /* Register table */ ret = ip6t_register_table(&packet_mangler); if (ret < 0) return ret; /* Register hooks */ ret = nf_register_hook(&ip6t_ops[0]); if (ret < 0) goto cleanup_table; ret = nf_register_hook(&ip6t_ops[1]); if (ret < 0) goto cleanup_hook0; return ret; cleanup_hook0: nf_unregister_hook(&ip6t_ops[0]); cleanup_table: ip6t_unregister_table(&packet_mangler); return ret; } static void __exit fini(void) { unsigned int i; for (i = 0; i < sizeof(ip6t_ops)/sizeof(struct nf_hook_ops); i++) nf_unregister_hook(&ip6t_ops[i]); ip6t_unregister_table(&packet_mangler); } module_init(init); module_exit(fini); MODULE_LICENSE("GPL"); |