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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /net/ipv6/netfilter/ip6t_frag.c
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'net/ipv6/netfilter/ip6t_frag.c')
-rw-r--r--net/ipv6/netfilter/ip6t_frag.c229
1 files changed, 229 insertions, 0 deletions
diff --git a/net/ipv6/netfilter/ip6t_frag.c b/net/ipv6/netfilter/ip6t_frag.c
new file mode 100644
index 00000000000..4bfa30a9bc8
--- /dev/null
+++ b/net/ipv6/netfilter/ip6t_frag.c
@@ -0,0 +1,229 @@
+/* Kernel module to match FRAG 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_frag.h>
+
+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
+
+/* 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,
+ unsigned int protoff,
+ int *hotdrop)
+{
+ struct frag_hdr _frag, *fh = 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, *hp;
+
+ 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;
+ }
+
+ hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
+ BUG_ON(hp == NULL);
+
+ /* Calculate the header length */
+ if (nexthdr == NEXTHDR_FRAGMENT) {
+ hdrlen = 8;
+ } else if (nexthdr == NEXTHDR_AUTH)
+ hdrlen = (hp->hdrlen+2)<<2;
+ else
+ hdrlen = ipv6_optlen(hp);
+
+ /* 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 = hp->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 < sizeof(struct frag_hdr)){
+ *hotdrop = 1;
+ return 0;
+ }
+
+ fh = skb_header_pointer(skb, ptr, sizeof(_frag), &_frag);
+ BUG_ON(fh == NULL);
+
+ DEBUGP("INFO %04X ", fh->frag_off);
+ DEBUGP("OFFSET %04X ", ntohs(fh->frag_off) & ~0x7);
+ DEBUGP("RES %02X %04X", fh->reserved, ntohs(fh->frag_off) & 0x6);
+ DEBUGP("MF %04X ", fh->frag_off & htons(IP6_MF));
+ DEBUGP("ID %u %08X\n", ntohl(fh->identification),
+ ntohl(fh->identification));
+
+ DEBUGP("IPv6 FRAG id %02X ",
+ (id_match(fraginfo->ids[0], fraginfo->ids[1],
+ ntohl(fh->identification),
+ !!(fraginfo->invflags & IP6T_FRAG_INV_IDS))));
+ DEBUGP("res %02X %02X%04X %02X ",
+ (fraginfo->flags & IP6T_FRAG_RES), fh->reserved,
+ ntohs(fh->frag_off) & 0x6,
+ !((fraginfo->flags & IP6T_FRAG_RES)
+ && (fh->reserved || (ntohs(fh->frag_off) & 0x06))));
+ DEBUGP("first %02X %02X %02X ",
+ (fraginfo->flags & IP6T_FRAG_FST),
+ ntohs(fh->frag_off) & ~0x7,
+ !((fraginfo->flags & IP6T_FRAG_FST)
+ && (ntohs(fh->frag_off) & ~0x7)));
+ DEBUGP("mf %02X %02X %02X ",
+ (fraginfo->flags & IP6T_FRAG_MF),
+ ntohs(fh->frag_off) & IP6_MF,
+ !((fraginfo->flags & IP6T_FRAG_MF)
+ && !((ntohs(fh->frag_off) & IP6_MF))));
+ DEBUGP("last %02X %02X %02X\n",
+ (fraginfo->flags & IP6T_FRAG_NMF),
+ ntohs(fh->frag_off) & IP6_MF,
+ !((fraginfo->flags & IP6T_FRAG_NMF)
+ && (ntohs(fh->frag_off) & IP6_MF)));
+
+ return (fh != NULL)
+ &&
+ (id_match(fraginfo->ids[0], fraginfo->ids[1],
+ ntohl(fh->identification),
+ !!(fraginfo->invflags & IP6T_FRAG_INV_IDS)))
+ &&
+ !((fraginfo->flags & IP6T_FRAG_RES)
+ && (fh->reserved || (ntohs(fh->frag_off) & 0x6)))
+ &&
+ !((fraginfo->flags & IP6T_FRAG_FST)
+ && (ntohs(fh->frag_off) & ~0x7))
+ &&
+ !((fraginfo->flags & IP6T_FRAG_MF)
+ && !(ntohs(fh->frag_off) & IP6_MF))
+ &&
+ !((fraginfo->flags & IP6T_FRAG_NMF)
+ && (ntohs(fh->frag_off) & IP6_MF));
+}
+
+/* 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 = {
+ .name = "frag",
+ .match = &match,
+ .checkentry = &checkentry,
+ .me = 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);