107 lines
3.2 KiB
C
107 lines
3.2 KiB
C
|
/*
|
||
|
|
* IPv6 library code, needed by static components when full IPv6 support is
|
||
|
|
* not configured or static.
|
||
|
|
*/
|
||
|
|
#include <net/ipv6.h>
|
||
|
|
|
||
|
|
/*
|
||
|
|
* find out if nexthdr is a well-known extension header or a protocol
|
||
|
|
*/
|
||
|
|
|
||
|
|
int ipv6_ext_hdr(u8 nexthdr)
|
||
|
|
{
|
||
|
|
/*
|
||
|
|
* find out if nexthdr is an extension header or a protocol
|
||
|
|
*/
|
||
|
|
return ( (nexthdr == NEXTHDR_HOP) ||
|
||
|
|
(nexthdr == NEXTHDR_ROUTING) ||
|
||
|
|
(nexthdr == NEXTHDR_FRAGMENT) ||
|
||
|
|
(nexthdr == NEXTHDR_AUTH) ||
|
||
|
|
(nexthdr == NEXTHDR_NONE) ||
|
||
|
|
(nexthdr == NEXTHDR_DEST) );
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Skip any extension headers. This is used by the ICMP module.
|
||
|
|
*
|
||
|
|
* Note that strictly speaking this conflicts with RFC 2460 4.0:
|
||
|
|
* ...The contents and semantics of each extension header determine whether
|
||
|
|
* or not to proceed to the next header. Therefore, extension headers must
|
||
|
|
* be processed strictly in the order they appear in the packet; a
|
||
|
|
* receiver must not, for example, scan through a packet looking for a
|
||
|
|
* particular kind of extension header and process that header prior to
|
||
|
|
* processing all preceding ones.
|
||
|
|
*
|
||
|
|
* We do exactly this. This is a protocol bug. We can't decide after a
|
||
|
|
* seeing an unknown discard-with-error flavour TLV option if it's a
|
||
|
|
* ICMP error message or not (errors should never be send in reply to
|
||
|
|
* ICMP error messages).
|
||
|
|
*
|
||
|
|
* But I see no other way to do this. This might need to be reexamined
|
||
|
|
* when Linux implements ESP (and maybe AUTH) headers.
|
||
|
|
* --AK
|
||
|
|
*
|
||
|
|
* This function parses (probably truncated) exthdr set "hdr".
|
||
|
|
* "nexthdrp" initially points to some place,
|
||
|
|
* where type of the first header can be found.
|
||
|
|
*
|
||
|
|
* It skips all well-known exthdrs, and returns pointer to the start
|
||
|
|
* of unparsable area i.e. the first header with unknown type.
|
||
|
|
* If it is not NULL *nexthdr is updated by type/protocol of this header.
|
||
|
|
*
|
||
|
|
* NOTES: - if packet terminated with NEXTHDR_NONE it returns NULL.
|
||
|
|
* - it may return pointer pointing beyond end of packet,
|
||
|
|
* if the last recognized header is truncated in the middle.
|
||
|
|
* - if packet is truncated, so that all parsed headers are skipped,
|
||
|
|
* it returns NULL.
|
||
|
|
* - First fragment header is skipped, not-first ones
|
||
|
|
* are considered as unparsable.
|
||
|
|
* - ESP is unparsable for now and considered like
|
||
|
|
* normal payload protocol.
|
||
|
|
* - Note also special handling of AUTH header. Thanks to IPsec wizards.
|
||
|
|
*
|
||
|
|
* --ANK (980726)
|
||
|
|
*/
|
||
|
|
|
||
|
|
int ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp)
|
||
|
|
{
|
||
|
|
u8 nexthdr = *nexthdrp;
|
||
|
|
|
||
|
|
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;
|
||
|
|
|
||
|
|
if (ntohs(*fp) & ~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;
|
||
|
|
}
|
||
|
|
|
||
|
|
EXPORT_SYMBOL(ipv6_ext_hdr);
|
||
|
|
EXPORT_SYMBOL(ipv6_skip_exthdr);
|