Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* Kernel module to match Hop-by-Hop and Destination 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 | |
Jan Engelhardt | 6709dbb | 2007-02-07 15:11:19 -0800 | [diff] [blame] | 19 | #include <linux/netfilter/x_tables.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | #include <linux/netfilter_ipv6/ip6_tables.h> |
| 21 | #include <linux/netfilter_ipv6/ip6t_opts.h> |
| 22 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | MODULE_LICENSE("GPL"); |
Patrick McHardy | 5fa2a76 | 2006-08-22 00:43:55 -0700 | [diff] [blame] | 24 | MODULE_DESCRIPTION("IPv6 opts match"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>"); |
Patrick McHardy | 5fa2a76 | 2006-08-22 00:43:55 -0700 | [diff] [blame] | 26 | MODULE_ALIAS("ip6t_dst"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | /* |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 29 | * (Type & 0xC0) >> 6 |
| 30 | * 0 -> ignorable |
| 31 | * 1 -> must drop the packet |
| 32 | * 2 -> send ICMP PARM PROB regardless and drop packet |
| 33 | * 3 -> Send ICMP if not a multicast address and drop packet |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | * (Type & 0x20) >> 5 |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 35 | * 0 -> invariant |
| 36 | * 1 -> can change the routing |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | * (Type & 0x1F) Type |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 38 | * 0 -> Pad1 (only 1 byte!) |
| 39 | * 1 -> PadN LENGTH info (total length = length + 2) |
| 40 | * C0 | 2 -> JUMBO 4 x x x x ( xxxx > 64k ) |
| 41 | * 5 -> RTALERT 2 x x |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | */ |
| 43 | |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 44 | static bool |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | match(const struct sk_buff *skb, |
| 46 | const struct net_device *in, |
| 47 | const struct net_device *out, |
Patrick McHardy | c498673 | 2006-03-20 18:02:56 -0800 | [diff] [blame] | 48 | const struct xt_match *match, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 49 | const void *matchinfo, |
| 50 | int offset, |
| 51 | unsigned int protoff, |
Jan Engelhardt | cff533a | 2007-07-07 22:15:12 -0700 | [diff] [blame] | 52 | bool *hotdrop) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | { |
Jan Engelhardt | a47362a | 2007-07-07 22:16:55 -0700 | [diff] [blame] | 54 | struct ipv6_opt_hdr _optsh; |
| 55 | const struct ipv6_opt_hdr *oh; |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 56 | const struct ip6t_opts *optinfo = matchinfo; |
| 57 | unsigned int temp; |
| 58 | unsigned int ptr; |
| 59 | unsigned int hdrlen = 0; |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 60 | bool ret = false; |
Jan Engelhardt | a47362a | 2007-07-07 22:16:55 -0700 | [diff] [blame] | 61 | u8 _opttype; |
| 62 | u8 _optlen; |
| 63 | const u_int8_t *tp = NULL; |
| 64 | const u_int8_t *lp = NULL; |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 65 | unsigned int optlen; |
Patrick McHardy | 6d38163 | 2006-10-24 16:15:10 -0700 | [diff] [blame] | 66 | int err; |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 67 | |
Patrick McHardy | 6d38163 | 2006-10-24 16:15:10 -0700 | [diff] [blame] | 68 | err = ipv6_find_hdr(skb, &ptr, match->data, NULL); |
| 69 | if (err < 0) { |
| 70 | if (err != -ENOENT) |
Jan Engelhardt | cff533a | 2007-07-07 22:15:12 -0700 | [diff] [blame] | 71 | *hotdrop = true; |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 72 | return false; |
Patrick McHardy | 6d38163 | 2006-10-24 16:15:10 -0700 | [diff] [blame] | 73 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 75 | oh = skb_header_pointer(skb, ptr, sizeof(_optsh), &_optsh); |
| 76 | if (oh == NULL) { |
Jan Engelhardt | cff533a | 2007-07-07 22:15:12 -0700 | [diff] [blame] | 77 | *hotdrop = true; |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 78 | return false; |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 79 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 81 | hdrlen = ipv6_optlen(oh); |
| 82 | if (skb->len - ptr < hdrlen) { |
| 83 | /* Packet smaller than it's length field */ |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 84 | return false; |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 85 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame^] | 87 | pr_debug("IPv6 OPTS LEN %u %u ", hdrlen, oh->hdrlen); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame^] | 89 | pr_debug("len %02X %04X %02X ", |
| 90 | optinfo->hdrlen, hdrlen, |
| 91 | (!(optinfo->flags & IP6T_OPTS_LEN) || |
| 92 | ((optinfo->hdrlen == hdrlen) ^ |
| 93 | !!(optinfo->invflags & IP6T_OPTS_INV_LEN)))); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 95 | ret = (oh != NULL) && |
| 96 | (!(optinfo->flags & IP6T_OPTS_LEN) || |
| 97 | ((optinfo->hdrlen == hdrlen) ^ |
| 98 | !!(optinfo->invflags & IP6T_OPTS_INV_LEN))); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 100 | ptr += 2; |
| 101 | hdrlen -= 2; |
| 102 | if (!(optinfo->flags & IP6T_OPTS_OPTS)) { |
| 103 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | } else if (optinfo->flags & IP6T_OPTS_NSTRICT) { |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame^] | 105 | pr_debug("Not strict - not implemented"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | } else { |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame^] | 107 | pr_debug("Strict "); |
| 108 | pr_debug("#%d ", optinfo->optsnr); |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 109 | for (temp = 0; temp < optinfo->optsnr; temp++) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 110 | /* type field exists ? */ |
| 111 | if (hdrlen < 1) |
| 112 | break; |
| 113 | tp = skb_header_pointer(skb, ptr, sizeof(_opttype), |
| 114 | &_opttype); |
| 115 | if (tp == NULL) |
| 116 | break; |
| 117 | |
| 118 | /* Type check */ |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 119 | if (*tp != (optinfo->opts[temp] & 0xFF00) >> 8) { |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame^] | 120 | pr_debug("Tbad %02X %02X\n", *tp, |
| 121 | (optinfo->opts[temp] & 0xFF00) >> 8); |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 122 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 123 | } else { |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame^] | 124 | pr_debug("Tok "); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | } |
| 126 | /* Length check */ |
| 127 | if (*tp) { |
| 128 | u16 spec_len; |
| 129 | |
| 130 | /* length field exists ? */ |
| 131 | if (hdrlen < 2) |
| 132 | break; |
| 133 | lp = skb_header_pointer(skb, ptr + 1, |
| 134 | sizeof(_optlen), |
| 135 | &_optlen); |
| 136 | if (lp == NULL) |
| 137 | break; |
| 138 | spec_len = optinfo->opts[temp] & 0x00FF; |
| 139 | |
| 140 | if (spec_len != 0x00FF && spec_len != *lp) { |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame^] | 141 | pr_debug("Lbad %02X %04X\n", *lp, |
| 142 | spec_len); |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 143 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | } |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame^] | 145 | pr_debug("Lok "); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | optlen = *lp + 2; |
| 147 | } else { |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame^] | 148 | pr_debug("Pad1\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | optlen = 1; |
| 150 | } |
| 151 | |
| 152 | /* Step to the next */ |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame^] | 153 | pr_debug("len%04X \n", optlen); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | |
| 155 | if ((ptr > skb->len - optlen || hdrlen < optlen) && |
Jan Engelhardt | 7c4e36b | 2007-07-07 22:19:08 -0700 | [diff] [blame] | 156 | temp < optinfo->optsnr - 1) { |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame^] | 157 | pr_debug("new pointer is too large! \n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | break; |
| 159 | } |
| 160 | ptr += optlen; |
| 161 | hdrlen -= optlen; |
| 162 | } |
| 163 | if (temp == optinfo->optsnr) |
| 164 | return ret; |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 165 | else |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 166 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 167 | } |
| 168 | |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 169 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | } |
| 171 | |
| 172 | /* Called when user tries to insert an entry of this type. */ |
Jan Engelhardt | ccb79bd | 2007-07-07 22:16:00 -0700 | [diff] [blame] | 173 | static bool |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 174 | checkentry(const char *tablename, |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 175 | const void *entry, |
Patrick McHardy | c498673 | 2006-03-20 18:02:56 -0800 | [diff] [blame] | 176 | const struct xt_match *match, |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 177 | void *matchinfo, |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 178 | unsigned int hook_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | { |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 180 | const struct ip6t_opts *optsinfo = matchinfo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 182 | if (optsinfo->invflags & ~IP6T_OPTS_INV_MASK) { |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame^] | 183 | pr_debug("ip6t_opts: unknown flags %X\n", optsinfo->invflags); |
Jan Engelhardt | ccb79bd | 2007-07-07 22:16:00 -0700 | [diff] [blame] | 184 | return false; |
Yasuyuki Kozakai | f0daaa6 | 2006-01-17 02:39:39 -0800 | [diff] [blame] | 185 | } |
Jan Engelhardt | ccb79bd | 2007-07-07 22:16:00 -0700 | [diff] [blame] | 186 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | } |
| 188 | |
Patrick McHardy | 9f15c53 | 2007-07-07 22:22:02 -0700 | [diff] [blame] | 189 | static struct xt_match opts_match[] __read_mostly = { |
Patrick McHardy | 5fa2a76 | 2006-08-22 00:43:55 -0700 | [diff] [blame] | 190 | { |
| 191 | .name = "hbh", |
| 192 | .family = AF_INET6, |
| 193 | .match = match, |
| 194 | .matchsize = sizeof(struct ip6t_opts), |
| 195 | .checkentry = checkentry, |
| 196 | .me = THIS_MODULE, |
| 197 | .data = NEXTHDR_HOP, |
| 198 | }, |
| 199 | { |
| 200 | .name = "dst", |
| 201 | .family = AF_INET6, |
| 202 | .match = match, |
| 203 | .matchsize = sizeof(struct ip6t_opts), |
| 204 | .checkentry = checkentry, |
| 205 | .me = THIS_MODULE, |
| 206 | .data = NEXTHDR_DEST, |
| 207 | }, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 208 | }; |
| 209 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 210 | static int __init ip6t_hbh_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | { |
Patrick McHardy | 5fa2a76 | 2006-08-22 00:43:55 -0700 | [diff] [blame] | 212 | return xt_register_matches(opts_match, ARRAY_SIZE(opts_match)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 213 | } |
| 214 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 215 | static void __exit ip6t_hbh_fini(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 216 | { |
Patrick McHardy | 5fa2a76 | 2006-08-22 00:43:55 -0700 | [diff] [blame] | 217 | xt_unregister_matches(opts_match, ARRAY_SIZE(opts_match)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 218 | } |
| 219 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 220 | module_init(ip6t_hbh_init); |
| 221 | module_exit(ip6t_hbh_fini); |