[NETFILTER] ip6tables: remove duplicate code
Some IPv6 matches have very similar loops to find IPv6 extension header
and we can unify them. This patch introduces ipv6_find_hdr() to do it.
I just checked that it can find the target headers in the packet which has
dst,hbh,rt,frag,ah,esp headers.
Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 1cb8adb..2da514b 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1955,6 +1955,57 @@
#endif
}
+/*
+ * find specified header up to transport protocol header.
+ * If found target header, the offset to the header is set to *offset
+ * and return 0. otherwise, return -1.
+ *
+ * Notes: - non-1st Fragment Header isn't skipped.
+ * - ESP header isn't skipped.
+ * - The target header may be trancated.
+ */
+int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, u8 target)
+{
+ unsigned int start = (u8*)(skb->nh.ipv6h + 1) - skb->data;
+ u8 nexthdr = skb->nh.ipv6h->nexthdr;
+ unsigned int len = skb->len - start;
+
+ while (nexthdr != target) {
+ struct ipv6_opt_hdr _hdr, *hp;
+ unsigned int hdrlen;
+
+ if ((!ipv6_ext_hdr(nexthdr)) || nexthdr == NEXTHDR_NONE)
+ return -1;
+ hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr);
+ if (hp == NULL)
+ return -1;
+ if (nexthdr == NEXTHDR_FRAGMENT) {
+ unsigned short _frag_off, *fp;
+ fp = skb_header_pointer(skb,
+ start+offsetof(struct frag_hdr,
+ frag_off),
+ sizeof(_frag_off),
+ &_frag_off);
+ if (fp == NULL)
+ return -1;
+
+ if (ntohs(*fp) & ~0x7)
+ return -1;
+ hdrlen = 8;
+ } else if (nexthdr == NEXTHDR_AUTH)
+ hdrlen = (hp->hdrlen + 2) << 2;
+ else
+ hdrlen = ipv6_optlen(hp);
+
+ nexthdr = hp->nexthdr;
+ len -= hdrlen;
+ start += hdrlen;
+ }
+
+ *offset = start;
+ return 0;
+}
+
EXPORT_SYMBOL(ip6t_register_table);
EXPORT_SYMBOL(ip6t_unregister_table);
EXPORT_SYMBOL(ip6t_do_table);
@@ -1963,6 +2014,7 @@
EXPORT_SYMBOL(ip6t_register_target);
EXPORT_SYMBOL(ip6t_unregister_target);
EXPORT_SYMBOL(ip6t_ext_hdr);
+EXPORT_SYMBOL(ipv6_find_hdr);
module_init(init);
module_exit(fini);