ipv6: improve ipv6_find_hdr() to skip empty routing headers

This patch prepares ipv6_find_hdr() function so that it could be
able to skip routing headers, where segements_left is 0. This is
required to handle multiple routing header case correctly when
changing IPv6 addresses.

Signed-off-by: Ansis Atteka <aatteka@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index b2f0cfb0a381af666b6ab638e0fc8d2cc5cf60f8..acbd8e0343100c751794f46e13e79fce9b6db4a6 100644 (file)
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -631,8 +631,9 @@ extern int                  ipv6_skip_exthdr(const struct sk_buff *, int start,
 extern bool                    ipv6_ext_hdr(u8 nexthdr);
 
 enum {
-       IP6_FH_F_FRAG   = (1 << 0),
-       IP6_FH_F_AUTH   = (1 << 1),
+       IP6_FH_F_FRAG           = (1 << 0),
+       IP6_FH_F_AUTH           = (1 << 1),
+       IP6_FH_F_SKIP_RH        = (1 << 2),
 };
 
 /* find specified header and get offset to it */

diff --git a/net/ipv6/exthdrs_core.c b/net/ipv6/exthdrs_core.c
index 8ea253ad35b1762e4b30dfa7e20ea71d092bc642..11b4e29c8452bb82a5d0a45e254f19f78f15908c 100644 (file)
--- a/net/ipv6/exthdrs_core.c
+++ b/net/ipv6/exthdrs_core.c
@@ -132,9 +132,11 @@ EXPORT_SYMBOL(ipv6_skip_exthdr);
  * *offset is meaningless and fragment offset is stored in *fragoff if fragoff
  * isn't NULL.
  *
- * if flags is not NULL and it's a fragment, then the frag flag IP6_FH_F_FRAG
- * will be set. If it's an AH header, the IP6_FH_F_AUTH flag is set and
- * target < 0, then this function will stop at the AH header.
+ * if flags is not NULL and it's a fragment, then the frag flag
+ * IP6_FH_F_FRAG will be set. If it's an AH header, the
+ * IP6_FH_F_AUTH flag is set and target < 0, then this function will
+ * stop at the AH header. If IP6_FH_F_SKIP_RH flag was passed, then this
+ * function will skip all those routing headers, where segements_left was 0.
  */
 int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset,
                  int target, unsigned short *fragoff, int *flags)
@@ -142,6 +144,7 @@ int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset,
        unsigned int start = skb_network_offset(skb) + sizeof(struct ipv6hdr);
        u8 nexthdr = ipv6_hdr(skb)->nexthdr;
        unsigned int len;
+       bool found;
 
        if (fragoff)
                *fragoff = 0;
@@ -159,9 +162,10 @@ int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset,
        }
        len = skb->len - start;
 
-       while (nexthdr != target) {
+       do {
                struct ipv6_opt_hdr _hdr, *hp;
                unsigned int hdrlen;
+               found = (nexthdr == target);
 
                if ((!ipv6_ext_hdr(nexthdr)) || nexthdr == NEXTHDR_NONE) {
                        if (target < 0)
@@ -172,6 +176,20 @@ int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset,
                hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr);
                if (hp == NULL)
                        return -EBADMSG;
+
+               if (nexthdr == NEXTHDR_ROUTING) {
+                       struct ipv6_rt_hdr _rh, *rh;
+
+                       rh = skb_header_pointer(skb, start, sizeof(_rh),
+                                               &_rh);
+                       if (rh == NULL)
+                               return -EBADMSG;
+
+                       if (flags && (*flags & IP6_FH_F_SKIP_RH) &&
+                           rh->segments_left == 0)
+                               found = false;
+               }
+
                if (nexthdr == NEXTHDR_FRAGMENT) {
                        unsigned short _frag_off;
                        __be16 *fp;
@@ -205,10 +223,12 @@ int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset,
                } else
                        hdrlen = ipv6_optlen(hp);
 
-               nexthdr = hp->nexthdr;
-               len -= hdrlen;
-               start += hdrlen;
-       }
+               if (!found) {
+                       nexthdr = hp->nexthdr;
+                       len -= hdrlen;
+                       start += hdrlen;
+               }
+       } while (!found);
 
        *offset = start;
        return nexthdr;