git.openwrt.org Git - openwrt/staging/xback.git/blob

   1 From 89a23c8b528bd2c89f3981573d6cd7d23840c8a6 Mon Sep 17 00:00:00 2001
   2 From: Craig Gallek <cgallek@google.com>
   3 Date: Wed, 26 Apr 2017 14:37:45 -0400
   4 Subject: [PATCH] ip6_tunnel: Fix missing tunnel encapsulation limit option
   5
   6 The IPv6 tunneling code tries to insert IPV6_TLV_TNL_ENCAP_LIMIT and
   7 IPV6_TLV_PADN options when an encapsulation limit is defined (the
   8 default is a limit of 4).  An MTU adjustment is done to account for
   9 these options as well.  However, the options are never present in the
  10 generated packets.
  11
  12 The issue appears to be a subtlety between IPV6_DSTOPTS and
  13 IPV6_RTHDRDSTOPTS defined in RFC 3542.  When the IPIP tunnel driver was
  14 written, the encap limit options were included as IPV6_RTHDRDSTOPTS in
  15 dst0opt of struct ipv6_txoptions.  Later, ipv6_push_nfrags_opts was
  16 (correctly) updated to require IPV6_RTHDR options when IPV6_RTHDRDSTOPTS
  17 are to be used.  This caused the options to no longer be included in v6
  18 encapsulated packets.
  19
  20 The fix is to use IPV6_DSTOPTS (in dst1opt of struct ipv6_txoptions)
  21 instead.  IPV6_DSTOPTS do not have the additional IPV6_RTHDR requirement.
  22
  23 Fixes: 1df64a8569c7: ("[IPV6]: Add ip6ip6 tunnel driver.")
  24 Fixes: 333fad5364d6: ("[IPV6]: Support several new sockopt / ancillary data in Advanced API (RFC3542)")
  25 Signed-off-by: Craig Gallek <kraig@google.com>
  26 Signed-off-by: David S. Miller <davem@davemloft.net>
  27 ---
  28  net/ipv6/ip6_tunnel.c | 4 ++--
  29  1 file changed, 2 insertions(+), 2 deletions(-)
  30
  31 --- a/net/ipv6/ip6_tunnel.c
  32 +++ b/net/ipv6/ip6_tunnel.c
  33 @@ -957,7 +957,7 @@ static void init_tel_txopt(struct ipv6_t
  34         opt->dst_opt[5] = IPV6_TLV_PADN;
  35         opt->dst_opt[6] = 1;
  36
  37 -       opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt;
  38 +       opt->ops.dst1opt = (struct ipv6_opt_hdr *) opt->dst_opt;
  39         opt->ops.opt_nflen = 8;
  40  }
  41
  42 @@ -1191,7 +1191,7 @@ route_lookup:
  43
  44         if (encap_limit >= 0) {
  45                 init_tel_txopt(&opt, encap_limit);
  46 -               ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL);
  47 +               ipv6_push_frag_opts(skb, &opt.ops, &proto);
  48         }
  49
  50         /* Calculate max headroom for all the headers and adjust