Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* Kernel module to match ESP parameters. */ |
| 2 | |
| 3 | /* (C) 1999-2000 Yon Uriarte <yon@astaro.de> |
| 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/ip.h> |
| 13 | |
| 14 | #include <linux/netfilter_ipv4/ipt_esp.h> |
| 15 | #include <linux/netfilter_ipv4/ip_tables.h> |
| 16 | |
| 17 | MODULE_LICENSE("GPL"); |
| 18 | MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>"); |
| 19 | MODULE_DESCRIPTION("iptables ESP SPI match module"); |
| 20 | |
| 21 | #ifdef DEBUG_CONNTRACK |
| 22 | #define duprintf(format, args...) printk(format , ## args) |
| 23 | #else |
| 24 | #define duprintf(format, args...) |
| 25 | #endif |
| 26 | |
| 27 | /* Returns 1 if the spi is matched by the range, 0 otherwise */ |
| 28 | static inline int |
| 29 | spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert) |
| 30 | { |
| 31 | int r=0; |
| 32 | duprintf("esp spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ', |
| 33 | min,spi,max); |
| 34 | r=(spi >= min && spi <= max) ^ invert; |
| 35 | duprintf(" result %s\n",r? "PASS" : "FAILED"); |
| 36 | return r; |
| 37 | } |
| 38 | |
| 39 | static int |
| 40 | match(const struct sk_buff *skb, |
| 41 | const struct net_device *in, |
| 42 | const struct net_device *out, |
Patrick McHardy | c498673 | 2006-03-20 18:02:56 -0800 | [diff] [blame] | 43 | const struct xt_match *match, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | const void *matchinfo, |
| 45 | int offset, |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 46 | unsigned int protoff, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | int *hotdrop) |
| 48 | { |
| 49 | struct ip_esp_hdr _esp, *eh; |
| 50 | const struct ipt_esp *espinfo = matchinfo; |
| 51 | |
| 52 | /* Must not be a fragment. */ |
| 53 | if (offset) |
| 54 | return 0; |
| 55 | |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 56 | eh = skb_header_pointer(skb, protoff, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | sizeof(_esp), &_esp); |
| 58 | if (eh == NULL) { |
| 59 | /* We've been asked to examine this packet, and we |
| 60 | * can't. Hence, no choice but to drop. |
| 61 | */ |
| 62 | duprintf("Dropping evil ESP tinygram.\n"); |
| 63 | *hotdrop = 1; |
| 64 | return 0; |
| 65 | } |
| 66 | |
| 67 | return spi_match(espinfo->spis[0], espinfo->spis[1], |
| 68 | ntohl(eh->spi), |
| 69 | !!(espinfo->invflags & IPT_ESP_INV_SPI)); |
| 70 | } |
| 71 | |
| 72 | /* Called when user tries to insert an entry of this type. */ |
| 73 | static int |
| 74 | checkentry(const char *tablename, |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 75 | const void *ip_void, |
Patrick McHardy | c498673 | 2006-03-20 18:02:56 -0800 | [diff] [blame] | 76 | const struct xt_match *match, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | void *matchinfo, |
| 78 | unsigned int matchinfosize, |
| 79 | unsigned int hook_mask) |
| 80 | { |
| 81 | const struct ipt_esp *espinfo = matchinfo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | |
Patrick McHardy | 1d5cd90 | 2006-03-20 18:01:14 -0800 | [diff] [blame] | 83 | /* Must specify no unknown invflags */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | if (espinfo->invflags & ~IPT_ESP_INV_MASK) { |
Patrick McHardy | 1d5cd90 | 2006-03-20 18:01:14 -0800 | [diff] [blame] | 85 | duprintf("ipt_esp: unknown flags %X\n", espinfo->invflags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | return 0; |
| 87 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | return 1; |
| 89 | } |
| 90 | |
| 91 | static struct ipt_match esp_match = { |
| 92 | .name = "esp", |
Patrick McHardy | 1d5cd90 | 2006-03-20 18:01:14 -0800 | [diff] [blame] | 93 | .match = match, |
| 94 | .matchsize = sizeof(struct ipt_esp), |
| 95 | .proto = IPPROTO_ESP, |
| 96 | .checkentry = checkentry, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | .me = THIS_MODULE, |
| 98 | }; |
| 99 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 100 | static int __init ipt_esp_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 101 | { |
| 102 | return ipt_register_match(&esp_match); |
| 103 | } |
| 104 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 105 | static void __exit ipt_esp_fini(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | { |
| 107 | ipt_unregister_match(&esp_match); |
| 108 | } |
| 109 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 110 | module_init(ipt_esp_init); |
| 111 | module_exit(ipt_esp_fini); |