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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /net/ipv6/exthdrs_core.c | |
download | kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'net/ipv6/exthdrs_core.c')
-rw-r--r-- | net/ipv6/exthdrs_core.c | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/net/ipv6/exthdrs_core.c b/net/ipv6/exthdrs_core.c new file mode 100644 index 00000000000..6dda815c013 --- /dev/null +++ b/net/ipv6/exthdrs_core.c @@ -0,0 +1,109 @@ +/* + * 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" + * of length "len". "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, int len) +{ + u8 nexthdr = *nexthdrp; + + while (ipv6_ext_hdr(nexthdr)) { + struct ipv6_opt_hdr _hdr, *hp; + int hdrlen; + + if (len < (int)sizeof(struct ipv6_opt_hdr)) + return -1; + if (nexthdr == NEXTHDR_NONE) + return -1; + hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr); + if (hp == NULL) + BUG(); + if (nexthdr == NEXTHDR_FRAGMENT) { + unsigned short _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; + len -= hdrlen; + start += hdrlen; + } + + *nexthdrp = nexthdr; + return start; +} + +EXPORT_SYMBOL(ipv6_ext_hdr); +EXPORT_SYMBOL(ipv6_skip_exthdr); |