1 files changed, 43 insertions, 0 deletions

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 8d3a0e17314d..50ff49e518bc 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -49,6 +49,49 @@
 
 #include <asm/uaccess.h>
 
+int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
+{
+        int packet_len = skb->tail - skb->nh.raw;
+        struct ipv6_opt_hdr *hdr;
+        int len;
+
+        if (offset + 2 > packet_len)
+                goto bad;
+        hdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
+        len = ((hdr->hdrlen + 1) << 3);
+
+        if (offset + len > packet_len)
+                goto bad;
+
+        offset += 2;
+        len -= 2;
+
+        while (len > 0) {
+                int opttype = skb->nh.raw[offset];
+                int optlen;
+
+                if (opttype == type)
+                        return offset;
+
+                switch (opttype) {
+                case IPV6_TLV_PAD0:
+                        optlen = 1;
+                        break;
+                default:
+                        optlen = skb->nh.raw[offset + 1] + 2;
+                        if (optlen > len)
+                                goto bad;
+                        break;
+                }
+                offset += optlen;
+                len -= optlen;
+        }
+        /* not_found */
+        return -1;
+ bad:
+        return -1;
+}
+
 /*
  *      Parsing tlv encoded headers.
  *