This is a helper to search option offset from extension header which
can carry TLV option like destination options header.
Mobile IPv6 home address option will use it.
Based on MIPL2 kernel patch.
---
include/net/ipv6.h | 2 ++
net/ipv6/exthdrs.c | 43 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 45 insertions(+), 0 deletions(-)
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 4abedb8..2e78433 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -504,6 +504,8 @@ extern int ipv6_skip_exthdr(const stru
extern int ipv6_ext_hdr(u8 nexthdr);
+extern int ipv6_find_tlv(struct sk_buff *skb, int offset, int type);
+
extern struct ipv6_txoptions * ipv6_invert_rthdr(struct sock *sk,
struct ipv6_rt_hdr *hdr);
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 138cb12..fbedad9 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -49,6 +49,49 @@ #endif
#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.
*
--
1.4.1
-
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