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#include <linux/ipv6.h>
#include <linux/version.h>
#include <net/ipv6.h>
#if LINUX_VERSION_CODE < KERNEL_VERSION(3,3,0)
int rpl_ipv6_skip_exthdr(const struct sk_buff *skb, int start,
u8 *nexthdrp, __be16 *frag_offp)
{
u8 nexthdr = *nexthdrp;
*frag_offp = 0;
while (ipv6_ext_hdr(nexthdr)) {
struct ipv6_opt_hdr _hdr, *hp;
int hdrlen;
if (nexthdr == NEXTHDR_NONE)
return -1;
hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr);
if (hp == NULL)
return -1;
if (nexthdr == NEXTHDR_FRAGMENT) {
__be16 _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;
*frag_offp = *fp;
if (ntohs(*frag_offp) & ~0x7)
break;
hdrlen = 8;
} else if (nexthdr == NEXTHDR_AUTH)
hdrlen = (hp->hdrlen+2)<<2;
else
hdrlen = ipv6_optlen(hp);
nexthdr = hp->nexthdr;
start += hdrlen;
}
*nexthdrp = nexthdr;
return start;
}
#endif /* Kernel version < 3.3 */
/*
* find the offset to specified header or the protocol number of last header
* if target < 0. "last header" is transport protocol header, ESP, or
* "No next header".
*
* Note that *offset is used as input/output parameter. an if it is not zero,
* then it must be a valid offset to an inner IPv6 header. This can be used
* to explore inner IPv6 header, eg. ICMPv6 error messages.
*
* If target header is found, its offset is set in *offset and return protocol
* number. Otherwise, return -1.
*
* If the first fragment doesn't contain the final protocol header or
* NEXTHDR_NONE it is considered invalid.
*
* Note that non-1st fragment is special case that "the protocol number
* of last header" is "next header" field in Fragment header. In this case,
* *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
* OVS_IP6T_FH_F_FRAG will be set. If it's an AH header, the
* OVS_IP6T_FH_F_AUTH flag is set and target < 0, then this function will
* stop at the AH header. If OVS_IP6T_FH_F_SKIP_RH flag was passed, then this
* function will skip all those routing headers, where segements_left was 0.
*/
int rpl_ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset,
int target, unsigned short *fragoff, int *flags)
{
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;
if (*offset) {
struct ipv6hdr _ip6, *ip6;
ip6 = skb_header_pointer(skb, *offset, sizeof(_ip6), &_ip6);
if (!ip6 || (ip6->version != 6)) {
printk(KERN_ERR "IPv6 header not found\n");
return -EBADMSG;
}
start = *offset + sizeof(struct ipv6hdr);
nexthdr = ip6->nexthdr;
}
len = skb->len - start;
do {
struct ipv6_opt_hdr _hdr, *hp;
unsigned int hdrlen;
found = (nexthdr == target);
if ((!ipv6_ext_hdr(nexthdr)) || nexthdr == NEXTHDR_NONE) {
if (target < 0)
break;
return -ENOENT;
}
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 & OVS_IP6T_FH_F_SKIP_RH) &&
rh->segments_left == 0)
found = false;
}
if (nexthdr == NEXTHDR_FRAGMENT) {
unsigned short _frag_off;
__be16 *fp;
if (flags) /* Indicate that this is a fragment */
*flags |= OVS_IP6T_FH_F_FRAG;
fp = skb_header_pointer(skb,
start+offsetof(struct frag_hdr,
frag_off),
sizeof(_frag_off),
&_frag_off);
if (fp == NULL)
return -EBADMSG;
_frag_off = ntohs(*fp) & ~0x7;
if (_frag_off) {
if (target < 0 &&
((!ipv6_ext_hdr(hp->nexthdr)) ||
hp->nexthdr == NEXTHDR_NONE)) {
if (fragoff)
*fragoff = _frag_off;
return hp->nexthdr;
}
return -ENOENT;
}
hdrlen = 8;
} else if (nexthdr == NEXTHDR_AUTH) {
if (flags && (*flags & OVS_IP6T_FH_F_AUTH) &&
(target < 0))
break;
hdrlen = (hp->hdrlen + 2) << 2;
} else
hdrlen = ipv6_optlen(hp);
if (!found) {
nexthdr = hp->nexthdr;
len -= hdrlen;
start += hdrlen;
}
} while (!found);
*offset = start;
return nexthdr;
}
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