/* Kernel module to match ESP parameters. *//* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */#include <linux/module.h>#include <linux/skbuff.h>#include <linux/ipv6.h>#include <linux/types.h>#include <net/checksum.h>#include <net/ipv6.h>#include <linux/netfilter_ipv6/ip6_tables.h>#include <linux/netfilter_ipv6/ip6t_esp.h>MODULE_LICENSE("GPL");MODULE_DESCRIPTION("IPv6 ESP match");MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");#if 0#define DEBUGP printk#else#define DEBUGP(format, args...)#endif/* Returns 1 if the spi is matched by the range, 0 otherwise */static inline intspi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert){	int r=0;        DEBUGP("esp spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',        	min,spi,max);	r=(spi >= min && spi <= max) ^ invert;	DEBUGP(" result %s\n",r? "PASS\n" : "FAILED\n");	return r;}static intmatch(const struct sk_buff *skb,      const struct net_device *in,      const struct net_device *out,      const void *matchinfo,      int offset,      const void *protohdr,      u_int16_t datalen,      int *hotdrop){	struct ip_esp_hdr *esp = NULL;	const struct ip6t_esp *espinfo = matchinfo;	unsigned int temp;	int len;	u8 nexthdr;	unsigned int ptr;	/* Make sure this isn't an evil packet */	/*DEBUGP("ipv6_esp entered \n");*/	/* type of the 1st exthdr */	nexthdr = skb->nh.ipv6h->nexthdr;	/* pointer to the 1st exthdr */	ptr = sizeof(struct ipv6hdr);	/* available length */	len = skb->len - ptr;	temp = 0;        while (ip6t_ext_hdr(nexthdr)) {        	struct ipv6_opt_hdr *hdr;        	int hdrlen;		DEBUGP("ipv6_esp header iteration \n");		/* Is there enough space for the next ext header? */                if (len < (int)sizeof(struct ipv6_opt_hdr))                        return 0;		/* No more exthdr -> evaluate */                if (nexthdr == NEXTHDR_NONE) {			break;		}		/* ESP -> evaluate */                if (nexthdr == NEXTHDR_ESP) {			temp |= MASK_ESP;			break;		}		hdr=(struct ipv6_opt_hdr *)skb->data+ptr;		/* Calculate the header length */                if (nexthdr == NEXTHDR_FRAGMENT) {                        hdrlen = 8;                } else if (nexthdr == NEXTHDR_AUTH)                        hdrlen = (hdr->hdrlen+2)<<2;                else                        hdrlen = ipv6_optlen(hdr);		/* set the flag */		switch (nexthdr){			case NEXTHDR_HOP:			case NEXTHDR_ROUTING:			case NEXTHDR_FRAGMENT:			case NEXTHDR_AUTH:			case NEXTHDR_DEST:				break;			default:				DEBUGP("ipv6_esp match: unknown nextheader %u\n",nexthdr);				return 0;				break;		}                nexthdr = hdr->nexthdr;                len -= hdrlen;                ptr += hdrlen;		if ( ptr > skb->len ) {			DEBUGP("ipv6_esp: new pointer too large! \n");			break;		}        }	/* ESP header not found */	if ( temp != MASK_ESP ) return 0;       if (len < (int)sizeof(struct ip_esp_hdr)){	       *hotdrop = 1;       		return 0;       }	esp = (struct ip_esp_hdr *) (skb->data + ptr);	DEBUGP("IPv6 ESP SPI %u %08X\n", ntohl(esp->spi), ntohl(esp->spi));	return (esp != NULL)		&& spi_match(espinfo->spis[0], espinfo->spis[1],			      ntohl(esp->spi),			      !!(espinfo->invflags & IP6T_ESP_INV_SPI));}/* Called when user tries to insert an entry of this type. */static intcheckentry(const char *tablename,	   const struct ip6t_ip6 *ip,	   void *matchinfo,	   unsigned int matchinfosize,	   unsigned int hook_mask){	const struct ip6t_esp *espinfo = matchinfo;	if (matchinfosize != IP6T_ALIGN(sizeof(struct ip6t_esp))) {		DEBUGP("ip6t_esp: matchsize %u != %u\n",			 matchinfosize, IP6T_ALIGN(sizeof(struct ip6t_esp)));		return 0;	}	if (espinfo->invflags & ~IP6T_ESP_INV_MASK) {		DEBUGP("ip6t_esp: unknown flags %X\n",			 espinfo->invflags);		return 0;	}	return 1;}static struct ip6t_match esp_match = {	.name		= "esp",	.match		= &match,	.checkentry	= &checkentry,	.me		= THIS_MODULE,};static int __init init(void){	return ip6t_register_match(&esp_match);}static void __exit cleanup(void){	ip6t_unregister_match(&esp_match);}module_init(init);module_exit(cleanup);