- struct ip_auth_hdr *ah = NULL;
- const struct ip6t_ah *ahinfo = matchinfo;
- unsigned int temp;
- int len;
- u8 nexthdr;
- unsigned int ptr;
- unsigned int hdrlen = 0;
-
- /*DEBUGP("IPv6 AH entered\n");*/
- /* if (opt->auth == 0) return 0;
- * It does not filled on output */
-
- /* 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;
-
- DEBUGP("ipv6_ah 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) {
- 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);
-
- /* AH -> evaluate */
- if (nexthdr == NEXTHDR_AUTH) {
- temp |= MASK_AH;
- break;
- }
-
-
- /* set the flag */
- switch (nexthdr){
- case NEXTHDR_HOP:
- case NEXTHDR_ROUTING:
- case NEXTHDR_FRAGMENT:
- case NEXTHDR_AUTH:
- case NEXTHDR_DEST:
- break;
- default:
- DEBUGP("ipv6_ah match: unknown nextheader %u\n",nexthdr);
- return 0;
- break;
- }
-
- nexthdr = hdr->nexthdr;
- len -= hdrlen;
- ptr += hdrlen;
- if ( ptr > skb->len ) {
- DEBUGP("ipv6_ah: new pointer too large! \n");
- break;
- }
- }
-
- /* AH header not found */
- if ( temp != MASK_AH ) return 0;
-
- if (len < (int)sizeof(struct ip_auth_hdr)){
- *hotdrop = 1;
- return 0;
- }
-
- ah = (struct ip_auth_hdr *) (skb->data + ptr);
-
- DEBUGP("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen);
- DEBUGP("RES %04X ", ah->reserved);
- DEBUGP("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi));
-
- DEBUGP("IPv6 AH spi %02X ",
- (spi_match(ahinfo->spis[0], ahinfo->spis[1],
- ntohl(ah->spi),
- !!(ahinfo->invflags & IP6T_AH_INV_SPI))));
- DEBUGP("len %02X %04X %02X ",
- ahinfo->hdrlen, hdrlen,
- (!ahinfo->hdrlen ||
- (ahinfo->hdrlen == hdrlen) ^
- !!(ahinfo->invflags & IP6T_AH_INV_LEN)));
- DEBUGP("res %02X %04X %02X\n",
- ahinfo->hdrres, ah->reserved,
- !(ahinfo->hdrres && ah->reserved));
-
- return (ah != NULL)
- &&
- (spi_match(ahinfo->spis[0], ahinfo->spis[1],
- ntohl(ah->spi),
- !!(ahinfo->invflags & IP6T_AH_INV_SPI)))
- &&
- (!ahinfo->hdrlen ||
- (ahinfo->hdrlen == hdrlen) ^
- !!(ahinfo->invflags & IP6T_AH_INV_LEN))
- &&
- !(ahinfo->hdrres && ah->reserved);
+ struct ip_auth_hdr *ah, _ah;
+ const struct ip6t_ah *ahinfo = matchinfo;
+ unsigned int ptr;
+ unsigned int hdrlen = 0;
+ int err;
+
+ err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL);
+ if (err < 0) {
+ if (err != -ENOENT)
+ *hotdrop = 1;
+ return 0;
+ }
+
+ ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah);
+ if (ah == NULL) {
+ *hotdrop = 1;
+ return 0;
+ }
+
+ hdrlen = (ah->hdrlen + 2) << 2;
+
+ DEBUGP("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen);
+ DEBUGP("RES %04X ", ah->reserved);
+ DEBUGP("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi));
+
+ DEBUGP("IPv6 AH spi %02X ",
+ (spi_match(ahinfo->spis[0], ahinfo->spis[1],
+ ntohl(ah->spi),
+ !!(ahinfo->invflags & IP6T_AH_INV_SPI))));
+ DEBUGP("len %02X %04X %02X ",
+ ahinfo->hdrlen, hdrlen,
+ (!ahinfo->hdrlen ||
+ (ahinfo->hdrlen == hdrlen) ^
+ !!(ahinfo->invflags & IP6T_AH_INV_LEN)));
+ DEBUGP("res %02X %04X %02X\n",
+ ahinfo->hdrres, ah->reserved,
+ !(ahinfo->hdrres && ah->reserved));
+
+ return (ah != NULL)
+ &&
+ (spi_match(ahinfo->spis[0], ahinfo->spis[1],
+ ntohl(ah->spi),
+ !!(ahinfo->invflags & IP6T_AH_INV_SPI)))
+ &&
+ (!ahinfo->hdrlen ||
+ (ahinfo->hdrlen == hdrlen) ^
+ !!(ahinfo->invflags & IP6T_AH_INV_LEN))
+ &&
+ !(ahinfo->hdrres && ah->reserved);