/* Kernel module to match ESP parameters. */
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/* Kernel module to match ESP parameters. */
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#include <linux/module.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/skbuff.h>
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#include <linux/ipv6.h>
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#include <linux/ipv6.h>
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#include <linux/types.h>
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#include <linux/types.h>
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#include <net/checksum.h>
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#include <net/checksum.h>
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#include <net/ipv6.h>
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#include <net/ipv6.h>
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#include <linux/netfilter_ipv6/ip6_tables.h>
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#include <linux/netfilter_ipv6/ip6_tables.h>
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#include <linux/netfilter_ipv6/ip6t_esp.h>
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#include <linux/netfilter_ipv6/ip6t_esp.h>
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EXPORT_NO_SYMBOLS;
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EXPORT_NO_SYMBOLS;
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MODULE_LICENSE("GPL");
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("IPv6 ESP match");
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MODULE_DESCRIPTION("IPv6 ESP match");
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MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
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MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
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#if 0
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#if 0
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#define DEBUGP printk
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#define DEBUGP printk
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#else
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#else
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#define DEBUGP(format, args...)
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#define DEBUGP(format, args...)
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#endif
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#endif
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struct esphdr {
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struct esphdr {
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__u32 spi;
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__u32 spi;
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};
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};
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/* Returns 1 if the spi is matched by the range, 0 otherwise */
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/* Returns 1 if the spi is matched by the range, 0 otherwise */
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static inline int
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static inline int
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spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
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spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
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{
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{
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int r=0;
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int r=0;
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DEBUGP("esp spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
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DEBUGP("esp spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
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min,spi,max);
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min,spi,max);
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r=(spi >= min && spi <= max) ^ invert;
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r=(spi >= min && spi <= max) ^ invert;
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DEBUGP(" result %s\n",r? "PASS\n" : "FAILED\n");
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DEBUGP(" result %s\n",r? "PASS\n" : "FAILED\n");
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return r;
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return r;
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}
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}
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static int
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static int
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match(const struct sk_buff *skb,
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match(const struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *in,
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const struct net_device *out,
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const struct net_device *out,
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const void *matchinfo,
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const void *matchinfo,
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int offset,
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int offset,
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const void *protohdr,
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const void *protohdr,
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u_int16_t datalen,
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u_int16_t datalen,
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int *hotdrop)
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int *hotdrop)
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{
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{
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struct esphdr *esp = NULL;
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struct esphdr *esp = NULL;
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const struct ip6t_esp *espinfo = matchinfo;
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const struct ip6t_esp *espinfo = matchinfo;
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unsigned int temp;
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unsigned int temp;
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int len;
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int len;
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u8 nexthdr;
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u8 nexthdr;
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unsigned int ptr;
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unsigned int ptr;
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/* Make sure this isn't an evil packet */
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/* Make sure this isn't an evil packet */
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/*DEBUGP("ipv6_esp entered \n");*/
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/*DEBUGP("ipv6_esp entered \n");*/
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/* type of the 1st exthdr */
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/* type of the 1st exthdr */
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nexthdr = skb->nh.ipv6h->nexthdr;
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nexthdr = skb->nh.ipv6h->nexthdr;
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/* pointer to the 1st exthdr */
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/* pointer to the 1st exthdr */
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ptr = sizeof(struct ipv6hdr);
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ptr = sizeof(struct ipv6hdr);
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/* available length */
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/* available length */
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len = skb->len - ptr;
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len = skb->len - ptr;
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temp = 0;
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temp = 0;
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while (ip6t_ext_hdr(nexthdr)) {
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while (ip6t_ext_hdr(nexthdr)) {
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struct ipv6_opt_hdr *hdr;
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struct ipv6_opt_hdr *hdr;
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int hdrlen;
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int hdrlen;
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DEBUGP("ipv6_esp header iteration \n");
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DEBUGP("ipv6_esp header iteration \n");
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/* Is there enough space for the next ext header? */
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/* Is there enough space for the next ext header? */
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if (len < (int)sizeof(struct ipv6_opt_hdr))
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if (len < (int)sizeof(struct ipv6_opt_hdr))
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return 0;
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return 0;
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/* No more exthdr -> evaluate */
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/* No more exthdr -> evaluate */
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if (nexthdr == NEXTHDR_NONE) {
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if (nexthdr == NEXTHDR_NONE) {
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break;
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break;
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}
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}
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/* ESP -> evaluate */
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/* ESP -> evaluate */
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if (nexthdr == NEXTHDR_ESP) {
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if (nexthdr == NEXTHDR_ESP) {
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temp |= MASK_ESP;
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temp |= MASK_ESP;
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break;
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break;
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}
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}
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hdr=(struct ipv6_opt_hdr *)skb->data+ptr;
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hdr=(struct ipv6_opt_hdr *)skb->data+ptr;
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/* Calculate the header length */
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/* Calculate the header length */
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if (nexthdr == NEXTHDR_FRAGMENT) {
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if (nexthdr == NEXTHDR_FRAGMENT) {
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hdrlen = 8;
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hdrlen = 8;
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} else if (nexthdr == NEXTHDR_AUTH)
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} else if (nexthdr == NEXTHDR_AUTH)
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hdrlen = (hdr->hdrlen+2)<<2;
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hdrlen = (hdr->hdrlen+2)<<2;
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else
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else
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hdrlen = ipv6_optlen(hdr);
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hdrlen = ipv6_optlen(hdr);
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/* set the flag */
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/* set the flag */
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switch (nexthdr){
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switch (nexthdr){
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case NEXTHDR_HOP:
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case NEXTHDR_HOP:
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case NEXTHDR_ROUTING:
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case NEXTHDR_ROUTING:
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case NEXTHDR_FRAGMENT:
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case NEXTHDR_FRAGMENT:
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case NEXTHDR_AUTH:
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case NEXTHDR_AUTH:
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case NEXTHDR_DEST:
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case NEXTHDR_DEST:
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break;
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break;
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default:
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default:
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DEBUGP("ipv6_esp match: unknown nextheader %u\n",nexthdr);
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DEBUGP("ipv6_esp match: unknown nextheader %u\n",nexthdr);
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return 0;
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return 0;
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break;
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break;
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}
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}
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nexthdr = hdr->nexthdr;
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nexthdr = hdr->nexthdr;
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len -= hdrlen;
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len -= hdrlen;
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ptr += hdrlen;
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ptr += hdrlen;
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if ( ptr > skb->len ) {
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if ( ptr > skb->len ) {
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DEBUGP("ipv6_esp: new pointer too large! \n");
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DEBUGP("ipv6_esp: new pointer too large! \n");
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break;
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break;
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}
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}
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}
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}
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/* ESP header not found */
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/* ESP header not found */
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if ( temp != MASK_ESP ) return 0;
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if ( temp != MASK_ESP ) return 0;
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if (len < (int)sizeof(struct esphdr)){
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if (len < (int)sizeof(struct esphdr)){
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*hotdrop = 1;
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*hotdrop = 1;
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return 0;
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return 0;
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}
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}
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esp = (struct esphdr *) (skb->data + ptr);
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esp = (struct esphdr *) (skb->data + ptr);
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DEBUGP("IPv6 ESP SPI %u %08X\n", ntohl(esp->spi), ntohl(esp->spi));
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DEBUGP("IPv6 ESP SPI %u %08X\n", ntohl(esp->spi), ntohl(esp->spi));
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return (esp != NULL)
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return (esp != NULL)
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&& spi_match(espinfo->spis[0], espinfo->spis[1],
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&& spi_match(espinfo->spis[0], espinfo->spis[1],
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ntohl(esp->spi),
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ntohl(esp->spi),
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!!(espinfo->invflags & IP6T_ESP_INV_SPI));
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!!(espinfo->invflags & IP6T_ESP_INV_SPI));
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}
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}
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/* Called when user tries to insert an entry of this type. */
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/* Called when user tries to insert an entry of this type. */
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static int
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static int
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checkentry(const char *tablename,
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checkentry(const char *tablename,
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const struct ip6t_ip6 *ip,
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const struct ip6t_ip6 *ip,
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void *matchinfo,
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void *matchinfo,
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unsigned int matchinfosize,
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unsigned int matchinfosize,
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unsigned int hook_mask)
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unsigned int hook_mask)
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{
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{
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const struct ip6t_esp *espinfo = matchinfo;
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const struct ip6t_esp *espinfo = matchinfo;
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if (matchinfosize != IP6T_ALIGN(sizeof(struct ip6t_esp))) {
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if (matchinfosize != IP6T_ALIGN(sizeof(struct ip6t_esp))) {
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DEBUGP("ip6t_esp: matchsize %u != %u\n",
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DEBUGP("ip6t_esp: matchsize %u != %u\n",
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matchinfosize, IP6T_ALIGN(sizeof(struct ip6t_esp)));
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matchinfosize, IP6T_ALIGN(sizeof(struct ip6t_esp)));
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return 0;
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return 0;
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}
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}
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if (espinfo->invflags & ~IP6T_ESP_INV_MASK) {
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if (espinfo->invflags & ~IP6T_ESP_INV_MASK) {
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DEBUGP("ip6t_esp: unknown flags %X\n",
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DEBUGP("ip6t_esp: unknown flags %X\n",
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espinfo->invflags);
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espinfo->invflags);
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return 0;
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return 0;
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}
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}
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return 1;
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return 1;
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}
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}
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static struct ip6t_match esp_match
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static struct ip6t_match esp_match
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= { { NULL, NULL }, "esp", &match, &checkentry, NULL, THIS_MODULE };
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= { { NULL, NULL }, "esp", &match, &checkentry, NULL, THIS_MODULE };
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static int __init init(void)
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static int __init init(void)
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{
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{
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return ip6t_register_match(&esp_match);
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return ip6t_register_match(&esp_match);
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}
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}
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static void __exit cleanup(void)
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static void __exit cleanup(void)
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{
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{
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ip6t_unregister_match(&esp_match);
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ip6t_unregister_match(&esp_match);
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}
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}
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module_init(init);
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module_init(init);
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module_exit(cleanup);
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module_exit(cleanup);
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