patch-2.4.21 linux-2.4.21/net/ipv6/netfilter/ip6t_frag.c
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- Lines: 240
- Date:
2003-06-13 07:51:39.000000000 -0700
- Orig file:
linux-2.4.20/net/ipv6/netfilter/ip6t_frag.c
- Orig date:
1969-12-31 16:00:00.000000000 -0800
diff -urN linux-2.4.20/net/ipv6/netfilter/ip6t_frag.c linux-2.4.21/net/ipv6/netfilter/ip6t_frag.c
@@ -0,0 +1,239 @@
+/* Kernel module to match FRAG 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 <asm/byteorder.h>
+
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <linux/netfilter_ipv6/ip6t_frag.h>
+
+EXPORT_NO_SYMBOLS;
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("IPv6 FRAG match");
+MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(format, args...)
+#endif
+
+#if 0
+#if BYTE_ORDER == BIG_ENDIAN
+#define IP6F_OFF_MASK 0xfff8 /* mask out offset from _offlg */
+#define IP6F_RESERVED_MASK 0x0006 /* reserved bits in ip6f_offlg */
+#define IP6F_MORE_FRAG 0x0001 /* more-fragments flag */
+#else /* BYTE_ORDER == LITTLE_ENDIAN */
+#define IP6F_OFF_MASK 0xf8ff /* mask out offset from _offlg */
+#define IP6F_RESERVED_MASK 0x0600 /* reserved bits in ip6f_offlg */
+#define IP6F_MORE_FRAG 0x0100 /* more-fragments flag */
+#endif
+#endif
+
+#define IP6F_OFF_MASK 0xf8ff /* mask out offset from _offlg */
+#define IP6F_RESERVED_MASK 0x0600 /* reserved bits in ip6f_offlg */
+#define IP6F_MORE_FRAG 0x0100 /* more-fragments flag */
+
+struct fraghdr {
+ __u8 nexthdr;
+ __u8 hdrlen;
+ __u16 info;
+ __u32 id;
+};
+
+/* Returns 1 if the id is matched by the range, 0 otherwise */
+static inline int
+id_match(u_int32_t min, u_int32_t max, u_int32_t id, int invert)
+{
+ int r=0;
+ DEBUGP("frag id_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
+ min,id,max);
+ r=(id >= min && id <= max) ^ invert;
+ DEBUGP(" result %s\n",r? "PASS" : "FAILED");
+ 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 fraghdr *frag = NULL;
+ const struct ip6t_frag *fraginfo = matchinfo;
+ unsigned int temp;
+ int len;
+ u8 nexthdr;
+ unsigned int ptr;
+ unsigned int hdrlen = 0;
+
+ /* 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_frag 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);
+
+ /* FRAG -> evaluate */
+ if (nexthdr == NEXTHDR_FRAGMENT) {
+ temp |= MASK_FRAGMENT;
+ 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_frag match: unknown nextheader %u\n",nexthdr);
+ return 0;
+ break;
+ }
+
+ nexthdr = hdr->nexthdr;
+ len -= hdrlen;
+ ptr += hdrlen;
+ if ( ptr > skb->len ) {
+ DEBUGP("ipv6_frag: new pointer too large! \n");
+ break;
+ }
+ }
+
+ /* FRAG header not found */
+ if ( temp != MASK_FRAGMENT ) return 0;
+
+ if (len < (int)sizeof(struct fraghdr)){
+ *hotdrop = 1;
+ return 0;
+ }
+
+ frag=skb->data+ptr;
+
+ DEBUGP("IPv6 FRAG LEN %u %u ", hdrlen, frag->hdrlen);
+ DEBUGP("INFO %04X ", frag->info);
+ DEBUGP("OFFSET %04X ", frag->info & IP6F_OFF_MASK);
+ DEBUGP("RES %04X ", frag->info & IP6F_RESERVED_MASK);
+ DEBUGP("MF %04X ", frag->info & IP6F_MORE_FRAG);
+ DEBUGP("ID %u %08X\n", ntohl(frag->id), ntohl(frag->id));
+
+ DEBUGP("IPv6 FRAG id %02X ",
+ (id_match(fraginfo->ids[0], fraginfo->ids[1],
+ ntohl(frag->id),
+ !!(fraginfo->invflags & IP6T_FRAG_INV_IDS))));
+ DEBUGP("len %02X %04X %02X ",
+ fraginfo->hdrlen, hdrlen,
+ (!fraginfo->hdrlen ||
+ (fraginfo->hdrlen == hdrlen) ^
+ !!(fraginfo->invflags & IP6T_FRAG_INV_LEN)));
+ DEBUGP("res %02X %02X %02X ",
+ (fraginfo->flags & IP6T_FRAG_RES), frag->info & IP6F_RESERVED_MASK,
+ !((fraginfo->flags & IP6T_FRAG_RES) && (frag->info & IP6F_RESERVED_MASK)));
+ DEBUGP("first %02X %02X %02X ",
+ (fraginfo->flags & IP6T_FRAG_FST), frag->info & IP6F_OFF_MASK,
+ !((fraginfo->flags & IP6T_FRAG_FST) && (frag->info & IP6F_OFF_MASK)));
+ DEBUGP("mf %02X %02X %02X ",
+ (fraginfo->flags & IP6T_FRAG_MF), frag->info & IP6F_MORE_FRAG,
+ !((fraginfo->flags & IP6T_FRAG_MF) && !((frag->info & IP6F_MORE_FRAG))));
+ DEBUGP("last %02X %02X %02X\n",
+ (fraginfo->flags & IP6T_FRAG_NMF), frag->info & IP6F_MORE_FRAG,
+ !((fraginfo->flags & IP6T_FRAG_NMF) && (frag->info & IP6F_MORE_FRAG)));
+
+ return (frag != NULL)
+ &&
+ (id_match(fraginfo->ids[0], fraginfo->ids[1],
+ ntohl(frag->id),
+ !!(fraginfo->invflags & IP6T_FRAG_INV_IDS)))
+ &&
+ (!fraginfo->hdrlen ||
+ (fraginfo->hdrlen == hdrlen) ^
+ !!(fraginfo->invflags & IP6T_FRAG_INV_LEN))
+ &&
+ !((fraginfo->flags & IP6T_FRAG_RES) && (frag->info & IP6F_RESERVED_MASK))
+ &&
+ !((fraginfo->flags & IP6T_FRAG_FST) && (frag->info & IP6F_OFF_MASK))
+ &&
+ !((fraginfo->flags & IP6T_FRAG_MF) && !((frag->info & IP6F_MORE_FRAG)))
+ &&
+ !((fraginfo->flags & IP6T_FRAG_NMF) && (frag->info & IP6F_MORE_FRAG));
+}
+
+/* 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_frag *fraginfo = matchinfo;
+
+ if (matchinfosize != IP6T_ALIGN(sizeof(struct ip6t_frag))) {
+ DEBUGP("ip6t_frag: matchsize %u != %u\n",
+ matchinfosize, IP6T_ALIGN(sizeof(struct ip6t_frag)));
+ return 0;
+ }
+ if (fraginfo->invflags & ~IP6T_FRAG_INV_MASK) {
+ DEBUGP("ip6t_frag: unknown flags %X\n",
+ fraginfo->invflags);
+ return 0;
+ }
+
+ return 1;
+}
+
+static struct ip6t_match frag_match
+= { { NULL, NULL }, "frag", &match, &checkentry, NULL, THIS_MODULE };
+
+static int __init init(void)
+{
+ return ip6t_register_match(&frag_match);
+}
+
+static void __exit cleanup(void)
+{
+ ip6t_unregister_match(&frag_match);
+}
+
+module_init(init);
+module_exit(cleanup);
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