ia64/linux-2.6.18-xen.hg

view net/ipv6/exthdrs_core.c @ 673:3161879fdf22

[IA64] xencomm: support XENMEM_add_to_physmap and XENMEM_remove_from_phsymap

support XENMEM_add_to_physmap and XENMEM_remove_from_phsymap.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
author Isaku Yamahata <yamahata@valinux.co.jp>
date Tue Sep 16 21:26:15 2008 +0900 (2008-09-16)
parents 831230e53067
children
line source
1 /*
2 * IPv6 library code, needed by static components when full IPv6 support is
3 * not configured or static.
4 */
5 #include <net/ipv6.h>
7 /*
8 * find out if nexthdr is a well-known extension header or a protocol
9 */
11 int ipv6_ext_hdr(u8 nexthdr)
12 {
13 /*
14 * find out if nexthdr is an extension header or a protocol
15 */
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) );
22 }
24 /*
25 * Skip any extension headers. This is used by the ICMP module.
26 *
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.
34 *
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).
39 *
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.
42 * --AK
43 *
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.
47 *
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.
51 *
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,
56 * it returns NULL.
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.
62 *
63 * --ANK (980726)
64 */
66 int ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp)
67 {
68 u8 nexthdr = *nexthdrp;
70 while (ipv6_ext_hdr(nexthdr)) {
71 struct ipv6_opt_hdr _hdr, *hp;
72 int hdrlen;
74 if (nexthdr == NEXTHDR_NONE)
75 return -1;
76 hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr);
77 if (hp == NULL)
78 return -1;
79 if (nexthdr == NEXTHDR_FRAGMENT) {
80 unsigned short _frag_off, *fp;
81 fp = skb_header_pointer(skb,
82 start+offsetof(struct frag_hdr,
83 frag_off),
84 sizeof(_frag_off),
85 &_frag_off);
86 if (fp == NULL)
87 return -1;
89 if (ntohs(*fp) & ~0x7)
90 break;
91 hdrlen = 8;
92 } else if (nexthdr == NEXTHDR_AUTH)
93 hdrlen = (hp->hdrlen+2)<<2;
94 else
95 hdrlen = ipv6_optlen(hp);
97 nexthdr = hp->nexthdr;
98 start += hdrlen;
99 }
101 *nexthdrp = nexthdr;
102 return start;
103 }
105 EXPORT_SYMBOL(ipv6_ext_hdr);
106 EXPORT_SYMBOL(ipv6_skip_exthdr);