datapath/linux/compat/exthdrs_core.c

   1 #include <linux/ipv6.h>
   2 #include <linux/version.h>
   3 #include <net/ipv6.h>
   4
   5 #ifndef HAVE_IP6_FH_F_SKIP_RH
   6 #if LINUX_VERSION_CODE < KERNEL_VERSION(3,3,0)
   7 int rpl_ipv6_skip_exthdr(const struct sk_buff *skb, int start,
   8                          u8 *nexthdrp, __be16 *frag_offp)
   9 {
  10         u8 nexthdr = *nexthdrp;
  11
  12         *frag_offp = 0;
  13
  14         while (ipv6_ext_hdr(nexthdr)) {
  15                 struct ipv6_opt_hdr _hdr, *hp;
  16                 int hdrlen;
  17
  18                 if (nexthdr == NEXTHDR_NONE)
  19                         return -1;
  20                 hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr);
  21                 if (hp == NULL)
  22                         return -1;
  23                 if (nexthdr == NEXTHDR_FRAGMENT) {
  24                         __be16 _frag_off, *fp;
  25                         fp = skb_header_pointer(skb,
  26                                                 start+offsetof(struct frag_hdr,
  27                                                                frag_off),
  28                                                 sizeof(_frag_off),
  29                                                 &_frag_off);
  30                         if (fp == NULL)
  31                                 return -1;
  32
  33                         *frag_offp = *fp;
  34                         if (ntohs(*frag_offp) & ~0x7)
  35                                 break;
  36                         hdrlen = 8;
  37                 } else if (nexthdr == NEXTHDR_AUTH)
  38                         hdrlen = (hp->hdrlen+2)<<2;
  39                 else
  40                         hdrlen = ipv6_optlen(hp);
  41
  42                 nexthdr = hp->nexthdr;
  43                 start += hdrlen;
  44         }
  45
  46         *nexthdrp = nexthdr;
  47         return start;
  48 }
  49 #endif /* Kernel version < 3.3 */
  50
  51 /*
  52  * find the offset to specified header or the protocol number of last header
  53  * if target < 0. "last header" is transport protocol header, ESP, or
  54  * "No next header".
  55  *
  56  * Note that *offset is used as input/output parameter. an if it is not zero,
  57  * then it must be a valid offset to an inner IPv6 header. This can be used
  58  * to explore inner IPv6 header, eg. ICMPv6 error messages.
  59  *
  60  * If target header is found, its offset is set in *offset and return protocol
  61  * number. Otherwise, return -1.
  62  *
  63  * If the first fragment doesn't contain the final protocol header or
  64  * NEXTHDR_NONE it is considered invalid.
  65  *
  66  * Note that non-1st fragment is special case that "the protocol number
  67  * of last header" is "next header" field in Fragment header. In this case,
  68  * *offset is meaningless and fragment offset is stored in *fragoff if fragoff
  69  * isn't NULL.
  70  *
  71  * if flags is not NULL and it's a fragment, then the frag flag
  72  * IP6_FH_F_FRAG will be set. If it's an AH header, the
  73  * IP6_FH_F_AUTH flag is set and target < 0, then this function will
  74  * stop at the AH header. If IP6_FH_F_SKIP_RH flag was passed, then this
  75  * function will skip all those routing headers, where segements_left was 0.
  76  */
  77 int rpl_ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset,
  78                   int target, unsigned short *fragoff, int *flags)
  79 {
  80         unsigned int start = skb_network_offset(skb) + sizeof(struct ipv6hdr);
  81         u8 nexthdr = ipv6_hdr(skb)->nexthdr;
  82         unsigned int len;
  83         bool found;
  84
  85         if (fragoff)
  86                 *fragoff = 0;
  87
  88         if (*offset) {
  89                 struct ipv6hdr _ip6, *ip6;
  90
  91                 ip6 = skb_header_pointer(skb, *offset, sizeof(_ip6), &_ip6);
  92                 if (!ip6 || (ip6->version != 6)) {
  93                         printk(KERN_ERR "IPv6 header not found\n");
  94                         return -EBADMSG;
  95                 }
  96                 start = *offset + sizeof(struct ipv6hdr);
  97                 nexthdr = ip6->nexthdr;
  98         }
  99         len = skb->len - start;
 100
 101         do {
 102                 struct ipv6_opt_hdr _hdr, *hp;
 103                 unsigned int hdrlen;
 104                 found = (nexthdr == target);
 105
 106                 if ((!ipv6_ext_hdr(nexthdr)) || nexthdr == NEXTHDR_NONE) {
 107                         if (target < 0 || found)
 108                                 break;
 109                         return -ENOENT;
 110                 }
 111
 112                 hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr);
 113                 if (hp == NULL)
 114                         return -EBADMSG;
 115
 116                 if (nexthdr == NEXTHDR_ROUTING) {
 117                         struct ipv6_rt_hdr _rh, *rh;
 118
 119                         rh = skb_header_pointer(skb, start, sizeof(_rh),
 120                                                 &_rh);
 121                         if (rh == NULL)
 122                                 return -EBADMSG;
 123
 124                         if (flags && (*flags & IP6_FH_F_SKIP_RH) &&
 125                             rh->segments_left == 0)
 126                                 found = false;
 127                 }
 128
 129                 if (nexthdr == NEXTHDR_FRAGMENT) {
 130                         unsigned short _frag_off;
 131                         __be16 *fp;
 132
 133                         if (flags)      /* Indicate that this is a fragment */
 134                                 *flags |= IP6_FH_F_FRAG;
 135                         fp = skb_header_pointer(skb,
 136                                                 start+offsetof(struct frag_hdr,
 137                                                                frag_off),
 138                                                 sizeof(_frag_off),
 139                                                 &_frag_off);
 140                         if (fp == NULL)
 141                                 return -EBADMSG;
 142
 143                         _frag_off = ntohs(*fp) & ~0x7;
 144                         if (_frag_off) {
 145                                 if (target < 0 &&
 146                                     ((!ipv6_ext_hdr(hp->nexthdr)) ||
 147                                      hp->nexthdr == NEXTHDR_NONE)) {
 148                                         if (fragoff)
 149                                                 *fragoff = _frag_off;
 150                                         return hp->nexthdr;
 151                                 }
 152                                 return -ENOENT;
 153                         }
 154                         hdrlen = 8;
 155                 } else if (nexthdr == NEXTHDR_AUTH) {
 156                         if (flags && (*flags & IP6_FH_F_AUTH) && (target < 0))
 157                                 break;
 158                         hdrlen = (hp->hdrlen + 2) << 2;
 159                 } else
 160                         hdrlen = ipv6_optlen(hp);
 161
 162                 if (!found) {
 163                         nexthdr = hp->nexthdr;
 164                         len -= hdrlen;
 165                         start += hdrlen;
 166                 }
 167         } while (!found);
 168
 169         *offset = start;
 170         return nexthdr;
 171 }
 172
 173 #endif