2 * IPv6 library code, needed by static components when full IPv6 support is
3 * not configured or static.
8 * find out if nexthdr is a well-known extension header or a protocol
11 int ipv6_ext_hdr(u8 nexthdr
)
14 * find out if nexthdr is an extension header or a protocol
16 return ( (nexthdr
== NEXTHDR_HOP
) ||
17 (nexthdr
== NEXTHDR_ROUTING
) ||
18 (nexthdr
== NEXTHDR_FRAGMENT
) ||
19 (nexthdr
== NEXTHDR_AUTH
) ||
20 (nexthdr
== NEXTHDR_NONE
) ||
21 (nexthdr
== NEXTHDR_DEST
) );
25 * Skip any extension headers. This is used by the ICMP module.
27 * Note that strictly speaking this conflicts with RFC 2460 4.0:
28 * ...The contents and semantics of each extension header determine whether
29 * or not to proceed to the next header. Therefore, extension headers must
30 * be processed strictly in the order they appear in the packet; a
31 * receiver must not, for example, scan through a packet looking for a
32 * particular kind of extension header and process that header prior to
33 * processing all preceding ones.
35 * We do exactly this. This is a protocol bug. We can't decide after a
36 * seeing an unknown discard-with-error flavour TLV option if it's a
37 * ICMP error message or not (errors should never be send in reply to
38 * ICMP error messages).
40 * But I see no other way to do this. This might need to be reexamined
41 * when Linux implements ESP (and maybe AUTH) headers.
44 * This function parses (probably truncated) exthdr set "hdr".
45 * "nexthdrp" initially points to some place,
46 * where type of the first header can be found.
48 * It skips all well-known exthdrs, and returns pointer to the start
49 * of unparsable area i.e. the first header with unknown type.
50 * If it is not NULL *nexthdr is updated by type/protocol of this header.
52 * NOTES: - if packet terminated with NEXTHDR_NONE it returns NULL.
53 * - it may return pointer pointing beyond end of packet,
54 * if the last recognized header is truncated in the middle.
55 * - if packet is truncated, so that all parsed headers are skipped,
57 * - First fragment header is skipped, not-first ones
58 * are considered as unparsable.
59 * - ESP is unparsable for now and considered like
60 * normal payload protocol.
61 * - Note also special handling of AUTH header. Thanks to IPsec wizards.
66 int ipv6_skip_exthdr(const struct sk_buff
*skb
, int start
, u8
*nexthdrp
)
68 u8 nexthdr
= *nexthdrp
;
70 while (ipv6_ext_hdr(nexthdr
)) {
71 struct ipv6_opt_hdr _hdr
, *hp
;
74 if (nexthdr
== NEXTHDR_NONE
)
76 hp
= skb_header_pointer(skb
, start
, sizeof(_hdr
), &_hdr
);
79 if (nexthdr
== NEXTHDR_FRAGMENT
) {
80 __be16 _frag_off
, *fp
;
81 fp
= skb_header_pointer(skb
,
82 start
+offsetof(struct frag_hdr
,
89 if (ntohs(*fp
) & ~0x7)
92 } else if (nexthdr
== NEXTHDR_AUTH
)
93 hdrlen
= (hp
->hdrlen
+2)<<2;
95 hdrlen
= ipv6_optlen(hp
);
97 nexthdr
= hp
->nexthdr
;
105 EXPORT_SYMBOL(ipv6_ext_hdr
);
106 EXPORT_SYMBOL(ipv6_skip_exthdr
);
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