diff options
author | Jesse Gross <jesse@nicira.com> | 2012-11-09 17:05:07 -0800 |
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committer | Jesse Gross <jesse@nicira.com> | 2012-11-09 17:05:07 -0800 |
commit | f8f626754ebeca613cf1af2e6f890cfde0e74d5b (patch) | |
tree | 359723681fd28b4c6c523229dcf5c6c3fadfd60c /net/ipv6/exthdrs_core.c | |
parent | c0618533815d8d92b270f03c11042ea53a8045d2 (diff) |
ipv6: Move ipv6_find_hdr() out of Netfilter code.
Open vSwitch will soon also use ipv6_find_hdr() so this moves it
out of Netfilter-specific code into a more common location.
Signed-off-by: Jesse Gross <jesse@nicira.com>
Diffstat (limited to 'net/ipv6/exthdrs_core.c')
-rw-r--r-- | net/ipv6/exthdrs_core.c | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/net/ipv6/exthdrs_core.c b/net/ipv6/exthdrs_core.c index f73d59a14131..8ea253ad35b1 100644 --- a/net/ipv6/exthdrs_core.c +++ b/net/ipv6/exthdrs_core.c @@ -111,3 +111,106 @@ int ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp, return start; } EXPORT_SYMBOL(ipv6_skip_exthdr); + +/* + * 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 IP6_FH_F_FRAG + * will be set. If it's an AH header, the IP6_FH_F_AUTH flag is set and + * target < 0, then this function will stop at the AH header. + */ +int 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; + + 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; + + while (nexthdr != target) { + struct ipv6_opt_hdr _hdr, *hp; + unsigned int hdrlen; + + 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_FRAGMENT) { + unsigned short _frag_off; + __be16 *fp; + + if (flags) /* Indicate that this is a fragment */ + *flags |= IP6_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 & IP6_FH_F_AUTH) && (target < 0)) + break; + hdrlen = (hp->hdrlen + 2) << 2; + } else + hdrlen = ipv6_optlen(hp); + + nexthdr = hp->nexthdr; + len -= hdrlen; + start += hdrlen; + } + + *offset = start; + return nexthdr; +} +EXPORT_SYMBOL(ipv6_find_hdr); |