patch-2.4.21 linux-2.4.21/net/ipv6/netfilter/ip6t_ah.c
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- Lines: 208
- Date:
2003-06-13 07:51:39.000000000 -0700
- Orig file:
linux-2.4.20/net/ipv6/netfilter/ip6t_ah.c
- Orig date:
1969-12-31 16:00:00.000000000 -0800
diff -urN linux-2.4.20/net/ipv6/netfilter/ip6t_ah.c linux-2.4.21/net/ipv6/netfilter/ip6t_ah.c
@@ -0,0 +1,207 @@
+/* Kernel module to match AH parameters. */
+#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_ah.h>
+
+EXPORT_NO_SYMBOLS;
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("IPv6 AH match");
+MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(format, args...)
+#endif
+
+struct ahhdr {
+ __u8 nexthdr;
+ __u8 hdrlen;
+ __u16 reserved;
+ __u32 spi;
+};
+
+/* Returns 1 if the spi is matched by the range, 0 otherwise */
+static inline int
+spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
+{
+ int r=0;
+ DEBUGP("ah 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 int
+match(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 ahhdr *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 ahhdr)){
+ *hotdrop = 1;
+ return 0;
+ }
+
+ ah=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);
+}
+
+/* Called when user tries to insert an entry of this type. */
+static int
+checkentry(const char *tablename,
+ const struct ip6t_ip6 *ip,
+ void *matchinfo,
+ unsigned int matchinfosize,
+ unsigned int hook_mask)
+{
+ const struct ip6t_ah *ahinfo = matchinfo;
+
+ if (matchinfosize != IP6T_ALIGN(sizeof(struct ip6t_ah))) {
+ DEBUGP("ip6t_ah: matchsize %u != %u\n",
+ matchinfosize, IP6T_ALIGN(sizeof(struct ip6t_ah)));
+ return 0;
+ }
+ if (ahinfo->invflags & ~IP6T_AH_INV_MASK) {
+ DEBUGP("ip6t_ah: unknown flags %X\n",
+ ahinfo->invflags);
+ return 0;
+ }
+
+ return 1;
+}
+
+static struct ip6t_match ah_match
+= { { NULL, NULL }, "ah", &match, &checkentry, NULL, THIS_MODULE };
+
+static int __init init(void)
+{
+ return ip6t_register_match(&ah_match);
+}
+
+static void __exit cleanup(void)
+{
+ ip6t_unregister_match(&ah_match);
+}
+
+module_init(init);
+module_exit(cleanup);
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