1dc5ab2faSYasuyuki Kozakai /* Kernel module to match ESP parameters. */ 2dc5ab2faSYasuyuki Kozakai 3dc5ab2faSYasuyuki Kozakai /* (C) 1999-2000 Yon Uriarte <yon@astaro.de> 4dc5ab2faSYasuyuki Kozakai * 5dc5ab2faSYasuyuki Kozakai * This program is free software; you can redistribute it and/or modify 6dc5ab2faSYasuyuki Kozakai * it under the terms of the GNU General Public License version 2 as 7dc5ab2faSYasuyuki Kozakai * published by the Free Software Foundation. 8dc5ab2faSYasuyuki Kozakai */ 9dc5ab2faSYasuyuki Kozakai 10dc5ab2faSYasuyuki Kozakai #include <linux/module.h> 11dc5ab2faSYasuyuki Kozakai #include <linux/skbuff.h> 12dc5ab2faSYasuyuki Kozakai #include <linux/in.h> 13dc5ab2faSYasuyuki Kozakai #include <linux/ip.h> 14dc5ab2faSYasuyuki Kozakai 15dc5ab2faSYasuyuki Kozakai #include <linux/netfilter/xt_esp.h> 16dc5ab2faSYasuyuki Kozakai #include <linux/netfilter/x_tables.h> 17dc5ab2faSYasuyuki Kozakai 18dc5ab2faSYasuyuki Kozakai #include <linux/netfilter_ipv4/ip_tables.h> 19dc5ab2faSYasuyuki Kozakai #include <linux/netfilter_ipv6/ip6_tables.h> 20dc5ab2faSYasuyuki Kozakai 21dc5ab2faSYasuyuki Kozakai MODULE_LICENSE("GPL"); 22dc5ab2faSYasuyuki Kozakai MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>"); 23dc5ab2faSYasuyuki Kozakai MODULE_DESCRIPTION("x_tables ESP SPI match module"); 24dc5ab2faSYasuyuki Kozakai MODULE_ALIAS("ipt_esp"); 25dc5ab2faSYasuyuki Kozakai MODULE_ALIAS("ip6t_esp"); 26dc5ab2faSYasuyuki Kozakai 27dc5ab2faSYasuyuki Kozakai #if 0 28dc5ab2faSYasuyuki Kozakai #define duprintf(format, args...) printk(format , ## args) 29dc5ab2faSYasuyuki Kozakai #else 30dc5ab2faSYasuyuki Kozakai #define duprintf(format, args...) 31dc5ab2faSYasuyuki Kozakai #endif 32dc5ab2faSYasuyuki Kozakai 33dc5ab2faSYasuyuki Kozakai /* Returns 1 if the spi is matched by the range, 0 otherwise */ 34dc5ab2faSYasuyuki Kozakai static inline int 35dc5ab2faSYasuyuki Kozakai spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert) 36dc5ab2faSYasuyuki Kozakai { 37dc5ab2faSYasuyuki Kozakai int r = 0; 38dc5ab2faSYasuyuki Kozakai duprintf("esp spi_match:%c 0x%x <= 0x%x <= 0x%x", invert ? '!' : ' ', 39dc5ab2faSYasuyuki Kozakai min, spi, max); 40dc5ab2faSYasuyuki Kozakai r = (spi >= min && spi <= max) ^ invert; 41dc5ab2faSYasuyuki Kozakai duprintf(" result %s\n", r ? "PASS" : "FAILED"); 42dc5ab2faSYasuyuki Kozakai return r; 43dc5ab2faSYasuyuki Kozakai } 44dc5ab2faSYasuyuki Kozakai 45dc5ab2faSYasuyuki Kozakai static int 46dc5ab2faSYasuyuki Kozakai match(const struct sk_buff *skb, 47dc5ab2faSYasuyuki Kozakai const struct net_device *in, 48dc5ab2faSYasuyuki Kozakai const struct net_device *out, 49dc5ab2faSYasuyuki Kozakai const struct xt_match *match, 50dc5ab2faSYasuyuki Kozakai const void *matchinfo, 51dc5ab2faSYasuyuki Kozakai int offset, 52dc5ab2faSYasuyuki Kozakai unsigned int protoff, 53dc5ab2faSYasuyuki Kozakai int *hotdrop) 54dc5ab2faSYasuyuki Kozakai { 55dc5ab2faSYasuyuki Kozakai struct ip_esp_hdr _esp, *eh; 56dc5ab2faSYasuyuki Kozakai const struct xt_esp *espinfo = matchinfo; 57dc5ab2faSYasuyuki Kozakai 58dc5ab2faSYasuyuki Kozakai /* Must not be a fragment. */ 59dc5ab2faSYasuyuki Kozakai if (offset) 60dc5ab2faSYasuyuki Kozakai return 0; 61dc5ab2faSYasuyuki Kozakai 62dc5ab2faSYasuyuki Kozakai eh = skb_header_pointer(skb, protoff, sizeof(_esp), &_esp); 63dc5ab2faSYasuyuki Kozakai if (eh == NULL) { 64dc5ab2faSYasuyuki Kozakai /* We've been asked to examine this packet, and we 65dc5ab2faSYasuyuki Kozakai * can't. Hence, no choice but to drop. 66dc5ab2faSYasuyuki Kozakai */ 67dc5ab2faSYasuyuki Kozakai duprintf("Dropping evil ESP tinygram.\n"); 68dc5ab2faSYasuyuki Kozakai *hotdrop = 1; 69dc5ab2faSYasuyuki Kozakai return 0; 70dc5ab2faSYasuyuki Kozakai } 71dc5ab2faSYasuyuki Kozakai 72dc5ab2faSYasuyuki Kozakai return spi_match(espinfo->spis[0], espinfo->spis[1], ntohl(eh->spi), 73dc5ab2faSYasuyuki Kozakai !!(espinfo->invflags & XT_ESP_INV_SPI)); 74dc5ab2faSYasuyuki Kozakai } 75dc5ab2faSYasuyuki Kozakai 76dc5ab2faSYasuyuki Kozakai /* Called when user tries to insert an entry of this type. */ 77dc5ab2faSYasuyuki Kozakai static int 78dc5ab2faSYasuyuki Kozakai checkentry(const char *tablename, 79dc5ab2faSYasuyuki Kozakai const void *ip_void, 80dc5ab2faSYasuyuki Kozakai const struct xt_match *match, 81dc5ab2faSYasuyuki Kozakai void *matchinfo, 82dc5ab2faSYasuyuki Kozakai unsigned int matchinfosize, 83dc5ab2faSYasuyuki Kozakai unsigned int hook_mask) 84dc5ab2faSYasuyuki Kozakai { 85dc5ab2faSYasuyuki Kozakai const struct xt_esp *espinfo = matchinfo; 86dc5ab2faSYasuyuki Kozakai 87dc5ab2faSYasuyuki Kozakai if (espinfo->invflags & ~XT_ESP_INV_MASK) { 88dc5ab2faSYasuyuki Kozakai duprintf("xt_esp: unknown flags %X\n", espinfo->invflags); 89dc5ab2faSYasuyuki Kozakai return 0; 90dc5ab2faSYasuyuki Kozakai } 91dc5ab2faSYasuyuki Kozakai 92dc5ab2faSYasuyuki Kozakai return 1; 93dc5ab2faSYasuyuki Kozakai } 94dc5ab2faSYasuyuki Kozakai 954470bbc7SPatrick McHardy static struct xt_match xt_esp_match[] = { 964470bbc7SPatrick McHardy { 97dc5ab2faSYasuyuki Kozakai .name = "esp", 98dc5ab2faSYasuyuki Kozakai .family = AF_INET, 994470bbc7SPatrick McHardy .checkentry = checkentry, 1004470bbc7SPatrick McHardy .match = match, 101dc5ab2faSYasuyuki Kozakai .matchsize = sizeof(struct xt_esp), 1024470bbc7SPatrick McHardy .proto = IPPROTO_ESP, 103dc5ab2faSYasuyuki Kozakai .me = THIS_MODULE, 1044470bbc7SPatrick McHardy }, 1054470bbc7SPatrick McHardy { 106dc5ab2faSYasuyuki Kozakai .name = "esp", 107dc5ab2faSYasuyuki Kozakai .family = AF_INET6, 1084470bbc7SPatrick McHardy .checkentry = checkentry, 1094470bbc7SPatrick McHardy .match = match, 110dc5ab2faSYasuyuki Kozakai .matchsize = sizeof(struct xt_esp), 1114470bbc7SPatrick McHardy .proto = IPPROTO_ESP, 112dc5ab2faSYasuyuki Kozakai .me = THIS_MODULE, 1134470bbc7SPatrick McHardy }, 114dc5ab2faSYasuyuki Kozakai }; 115dc5ab2faSYasuyuki Kozakai 116dc5ab2faSYasuyuki Kozakai static int __init xt_esp_init(void) 117dc5ab2faSYasuyuki Kozakai { 1184470bbc7SPatrick McHardy return xt_register_matches(xt_esp_match, ARRAY_SIZE(xt_esp_match)); 119dc5ab2faSYasuyuki Kozakai } 120dc5ab2faSYasuyuki Kozakai 121dc5ab2faSYasuyuki Kozakai static void __exit xt_esp_cleanup(void) 122dc5ab2faSYasuyuki Kozakai { 1234470bbc7SPatrick McHardy xt_unregister_matches(xt_esp_match, ARRAY_SIZE(xt_esp_match)); 124dc5ab2faSYasuyuki Kozakai } 125dc5ab2faSYasuyuki Kozakai 126dc5ab2faSYasuyuki Kozakai module_init(xt_esp_init); 127dc5ab2faSYasuyuki Kozakai module_exit(xt_esp_cleanup); 128