Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 1 | /* Kernel module to match ROUTING parameters. */ |
| 2 | |
| 3 | /* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu> |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License version 2 as |
| 7 | * published by the Free Software Foundation. |
| 8 | */ |
| 9 | |
| 10 | #include <linux/module.h> |
| 11 | #include <linux/skbuff.h> |
| 12 | #include <linux/ipv6.h> |
| 13 | #include <linux/types.h> |
| 14 | #include <net/checksum.h> |
| 15 | #include <net/ipv6.h> |
| 16 | |
| 17 | #include <asm/byteorder.h> |
| 18 | |
| 19 | #include <linux/netfilter_ipv6/ip6_tables.h> |
| 20 | #include <linux/netfilter_ipv6/ip6t_rt.h> |
| 21 | |
| 22 | MODULE_LICENSE("GPL"); |
| 23 | MODULE_DESCRIPTION("IPv6 RT match"); |
| 24 | MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>"); |
| 25 | |
| 26 | #if 0 |
| 27 | #define DEBUGP printk |
| 28 | #else |
| 29 | #define DEBUGP(format, args...) |
| 30 | #endif |
| 31 | |
| 32 | /* Returns 1 if the id is matched by the range, 0 otherwise */ |
| 33 | static inline int |
| 34 | segsleft_match(u_int32_t min, u_int32_t max, u_int32_t id, int invert) |
| 35 | { |
| 36 | int r=0; |
| 37 | DEBUGP("rt segsleft_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ', |
| 38 | min,id,max); |
| 39 | r=(id >= min && id <= max) ^ invert; |
| 40 | DEBUGP(" result %s\n",r? "PASS" : "FAILED"); |
| 41 | return r; |
| 42 | } |
| 43 | |
| 44 | static int |
| 45 | match(const struct sk_buff *skb, |
| 46 | const struct net_device *in, |
| 47 | const struct net_device *out, |
| 48 | const void *matchinfo, |
| 49 | int offset, |
| 50 | unsigned int protoff, |
| 51 | int *hotdrop) |
| 52 | { |
| 53 | struct ipv6_rt_hdr _route, *rh = NULL; |
| 54 | const struct ip6t_rt *rtinfo = matchinfo; |
| 55 | unsigned int temp; |
| 56 | unsigned int len; |
| 57 | u8 nexthdr; |
| 58 | unsigned int ptr; |
| 59 | unsigned int hdrlen = 0; |
| 60 | unsigned int ret = 0; |
| 61 | struct in6_addr *ap, _addr; |
| 62 | |
| 63 | /* type of the 1st exthdr */ |
| 64 | nexthdr = skb->nh.ipv6h->nexthdr; |
| 65 | /* pointer to the 1st exthdr */ |
| 66 | ptr = sizeof(struct ipv6hdr); |
| 67 | /* available length */ |
| 68 | len = skb->len - ptr; |
| 69 | temp = 0; |
| 70 | |
| 71 | while (ip6t_ext_hdr(nexthdr)) { |
| 72 | struct ipv6_opt_hdr _hdr, *hp; |
| 73 | |
| 74 | DEBUGP("ipv6_rt header iteration \n"); |
| 75 | |
| 76 | /* Is there enough space for the next ext header? */ |
| 77 | if (len < (int)sizeof(struct ipv6_opt_hdr)) |
| 78 | return 0; |
| 79 | /* No more exthdr -> evaluate */ |
| 80 | if (nexthdr == NEXTHDR_NONE) { |
| 81 | break; |
| 82 | } |
| 83 | /* ESP -> evaluate */ |
| 84 | if (nexthdr == NEXTHDR_ESP) { |
| 85 | break; |
| 86 | } |
| 87 | |
| 88 | hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr); |
| 89 | BUG_ON(hp == NULL); |
| 90 | |
| 91 | /* Calculate the header length */ |
| 92 | if (nexthdr == NEXTHDR_FRAGMENT) { |
| 93 | hdrlen = 8; |
| 94 | } else if (nexthdr == NEXTHDR_AUTH) |
| 95 | hdrlen = (hp->hdrlen+2)<<2; |
| 96 | else |
| 97 | hdrlen = ipv6_optlen(hp); |
| 98 | |
| 99 | /* ROUTING -> evaluate */ |
| 100 | if (nexthdr == NEXTHDR_ROUTING) { |
| 101 | temp |= MASK_ROUTING; |
| 102 | break; |
| 103 | } |
| 104 | |
| 105 | |
| 106 | /* set the flag */ |
| 107 | switch (nexthdr){ |
| 108 | case NEXTHDR_HOP: |
| 109 | case NEXTHDR_ROUTING: |
| 110 | case NEXTHDR_FRAGMENT: |
| 111 | case NEXTHDR_AUTH: |
| 112 | case NEXTHDR_DEST: |
| 113 | break; |
| 114 | default: |
| 115 | DEBUGP("ipv6_rt match: unknown nextheader %u\n",nexthdr); |
| 116 | return 0; |
| 117 | break; |
| 118 | } |
| 119 | |
| 120 | nexthdr = hp->nexthdr; |
| 121 | len -= hdrlen; |
| 122 | ptr += hdrlen; |
| 123 | if ( ptr > skb->len ) { |
| 124 | DEBUGP("ipv6_rt: new pointer is too large! \n"); |
| 125 | break; |
| 126 | } |
| 127 | } |
| 128 | |
| 129 | /* ROUTING header not found */ |
| 130 | if ( temp != MASK_ROUTING ) return 0; |
| 131 | |
| 132 | if (len < (int)sizeof(struct ipv6_rt_hdr)){ |
| 133 | *hotdrop = 1; |
| 134 | return 0; |
| 135 | } |
| 136 | |
| 137 | if (len < hdrlen){ |
| 138 | /* Pcket smaller than its length field */ |
| 139 | return 0; |
| 140 | } |
| 141 | |
| 142 | rh = skb_header_pointer(skb, ptr, sizeof(_route), &_route); |
| 143 | BUG_ON(rh == NULL); |
| 144 | |
| 145 | DEBUGP("IPv6 RT LEN %u %u ", hdrlen, rh->hdrlen); |
| 146 | DEBUGP("TYPE %04X ", rh->type); |
| 147 | DEBUGP("SGS_LEFT %u %02X\n", rh->segments_left, rh->segments_left); |
| 148 | |
| 149 | DEBUGP("IPv6 RT segsleft %02X ", |
| 150 | (segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1], |
| 151 | rh->segments_left, |
| 152 | !!(rtinfo->invflags & IP6T_RT_INV_SGS)))); |
| 153 | DEBUGP("type %02X %02X %02X ", |
| 154 | rtinfo->rt_type, rh->type, |
| 155 | (!(rtinfo->flags & IP6T_RT_TYP) || |
| 156 | ((rtinfo->rt_type == rh->type) ^ |
| 157 | !!(rtinfo->invflags & IP6T_RT_INV_TYP)))); |
| 158 | DEBUGP("len %02X %04X %02X ", |
| 159 | rtinfo->hdrlen, hdrlen, |
| 160 | (!(rtinfo->flags & IP6T_RT_LEN) || |
| 161 | ((rtinfo->hdrlen == hdrlen) ^ |
| 162 | !!(rtinfo->invflags & IP6T_RT_INV_LEN)))); |
| 163 | DEBUGP("res %02X %02X %02X ", |
| 164 | (rtinfo->flags & IP6T_RT_RES), ((struct rt0_hdr *)rh)->bitmap, |
| 165 | !((rtinfo->flags & IP6T_RT_RES) && (((struct rt0_hdr *)rh)->bitmap))); |
| 166 | |
| 167 | ret = (rh != NULL) |
| 168 | && |
| 169 | (segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1], |
| 170 | rh->segments_left, |
| 171 | !!(rtinfo->invflags & IP6T_RT_INV_SGS))) |
| 172 | && |
| 173 | (!(rtinfo->flags & IP6T_RT_LEN) || |
| 174 | ((rtinfo->hdrlen == hdrlen) ^ |
| 175 | !!(rtinfo->invflags & IP6T_RT_INV_LEN))) |
| 176 | && |
| 177 | (!(rtinfo->flags & IP6T_RT_TYP) || |
| 178 | ((rtinfo->rt_type == rh->type) ^ |
| 179 | !!(rtinfo->invflags & IP6T_RT_INV_TYP))); |
| 180 | |
| 181 | if (ret && (rtinfo->flags & IP6T_RT_RES)) { |
| 182 | u_int32_t *bp, _bitmap; |
| 183 | bp = skb_header_pointer(skb, |
| 184 | ptr + offsetof(struct rt0_hdr, bitmap), |
| 185 | sizeof(_bitmap), &_bitmap); |
| 186 | |
| 187 | ret = (*bp == 0); |
| 188 | } |
| 189 | |
| 190 | DEBUGP("#%d ",rtinfo->addrnr); |
| 191 | if ( !(rtinfo->flags & IP6T_RT_FST) ){ |
| 192 | return ret; |
| 193 | } else if (rtinfo->flags & IP6T_RT_FST_NSTRICT) { |
| 194 | DEBUGP("Not strict "); |
| 195 | if ( rtinfo->addrnr > (unsigned int)((hdrlen-8)/16) ){ |
| 196 | DEBUGP("There isn't enough space\n"); |
| 197 | return 0; |
| 198 | } else { |
| 199 | unsigned int i = 0; |
| 200 | |
| 201 | DEBUGP("#%d ",rtinfo->addrnr); |
| 202 | for(temp=0; temp<(unsigned int)((hdrlen-8)/16); temp++){ |
| 203 | ap = skb_header_pointer(skb, |
| 204 | ptr |
| 205 | + sizeof(struct rt0_hdr) |
| 206 | + temp * sizeof(_addr), |
| 207 | sizeof(_addr), |
| 208 | &_addr); |
| 209 | |
| 210 | BUG_ON(ap == NULL); |
| 211 | |
| 212 | if (ipv6_addr_equal(ap, &rtinfo->addrs[i])) { |
| 213 | DEBUGP("i=%d temp=%d;\n",i,temp); |
| 214 | i++; |
| 215 | } |
| 216 | if (i==rtinfo->addrnr) break; |
| 217 | } |
| 218 | DEBUGP("i=%d #%d\n", i, rtinfo->addrnr); |
| 219 | if (i == rtinfo->addrnr) |
| 220 | return ret; |
| 221 | else return 0; |
| 222 | } |
| 223 | } else { |
| 224 | DEBUGP("Strict "); |
| 225 | if ( rtinfo->addrnr > (unsigned int)((hdrlen-8)/16) ){ |
| 226 | DEBUGP("There isn't enough space\n"); |
| 227 | return 0; |
| 228 | } else { |
| 229 | DEBUGP("#%d ",rtinfo->addrnr); |
| 230 | for(temp=0; temp<rtinfo->addrnr; temp++){ |
| 231 | ap = skb_header_pointer(skb, |
| 232 | ptr |
| 233 | + sizeof(struct rt0_hdr) |
| 234 | + temp * sizeof(_addr), |
| 235 | sizeof(_addr), |
| 236 | &_addr); |
| 237 | BUG_ON(ap == NULL); |
| 238 | |
| 239 | if (!ipv6_addr_equal(ap, &rtinfo->addrs[temp])) |
| 240 | break; |
| 241 | } |
| 242 | DEBUGP("temp=%d #%d\n", temp, rtinfo->addrnr); |
| 243 | if ((temp == rtinfo->addrnr) && (temp == (unsigned int)((hdrlen-8)/16))) |
| 244 | return ret; |
| 245 | else return 0; |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | return 0; |
| 250 | } |
| 251 | |
| 252 | /* Called when user tries to insert an entry of this type. */ |
| 253 | static int |
| 254 | checkentry(const char *tablename, |
| 255 | const struct ip6t_ip6 *ip, |
| 256 | void *matchinfo, |
| 257 | unsigned int matchinfosize, |
| 258 | unsigned int hook_mask) |
| 259 | { |
| 260 | const struct ip6t_rt *rtinfo = matchinfo; |
| 261 | |
| 262 | if (matchinfosize != IP6T_ALIGN(sizeof(struct ip6t_rt))) { |
| 263 | DEBUGP("ip6t_rt: matchsize %u != %u\n", |
| 264 | matchinfosize, IP6T_ALIGN(sizeof(struct ip6t_rt))); |
| 265 | return 0; |
| 266 | } |
| 267 | if (rtinfo->invflags & ~IP6T_RT_INV_MASK) { |
| 268 | DEBUGP("ip6t_rt: unknown flags %X\n", |
| 269 | rtinfo->invflags); |
| 270 | return 0; |
| 271 | } |
| 272 | if ( (rtinfo->flags & (IP6T_RT_RES|IP6T_RT_FST_MASK)) && |
| 273 | (!(rtinfo->flags & IP6T_RT_TYP) || |
| 274 | (rtinfo->rt_type != 0) || |
| 275 | (rtinfo->invflags & IP6T_RT_INV_TYP)) ) { |
| 276 | DEBUGP("`--rt-type 0' required before `--rt-0-*'"); |
| 277 | return 0; |
| 278 | } |
| 279 | |
| 280 | return 1; |
| 281 | } |
| 282 | |
| 283 | static struct ip6t_match rt_match = { |
| 284 | .name = "rt", |
| 285 | .match = &match, |
| 286 | .checkentry = &checkentry, |
| 287 | .me = THIS_MODULE, |
| 288 | }; |
| 289 | |
| 290 | static int __init init(void) |
| 291 | { |
| 292 | return ip6t_register_match(&rt_match); |
| 293 | } |
| 294 | |
| 295 | static void __exit cleanup(void) |
| 296 | { |
| 297 | ip6t_unregister_match(&rt_match); |
| 298 | } |
| 299 | |
| 300 | module_init(init); |
| 301 | module_exit(cleanup); |