This fix addresses two problems in the way the DSCP field is formulated on the encapsulating header of IPv6 tunnels.
1) The IPv6 tunneling code was manipulating the DSCP field of the encapsulating packet using the 32b flowlabel. Since the flowlabel is only the lower 20b it was incorrect to assume that the upper 12b containing the DSCP and ECN fields would remain intact when formulating the encapsulating header. This fix handles the 'inherit' and 'fixed-value' DSCP cases explicitly using the extant dsfield u8 variable. 2) The use of INET_ECN_encapsulate(0, dsfield) in ip6_tnl_xmit was incorrect and resulted in the DSCP value always being set to 0. Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=195661 Signed-off-by: Peter Dawson <peter.a.daw...@boeing.com> --- net/ipv6/ip6_gre.c | 13 +++++++------ net/ipv6/ip6_tunnel.c | 21 +++++++++++++-------- 2 files changed, 20 insertions(+), 14 deletions(-) diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index 8d128ba..0c5b4caa 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -537,11 +537,10 @@ static inline int ip6gre_xmit_ipv4(struct sk_buff *skb, struct net_device *dev) memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6)); - dsfield = ipv4_get_dsfield(iph); - if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS) - fl6.flowlabel |= htonl((__u32)iph->tos << IPV6_TCLASS_SHIFT) - & IPV6_TCLASS_MASK; + dsfield = ipv4_get_dsfield(iph); + else + dsfield = ip6_tclass(t->parms.flowinfo); if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK) fl6.flowi6_mark = skb->mark; else @@ -598,9 +597,11 @@ static inline int ip6gre_xmit_ipv6(struct sk_buff *skb, struct net_device *dev) memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6)); - dsfield = ipv6_get_dsfield(ipv6h); if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS) - fl6.flowlabel |= (*(__be32 *) ipv6h & IPV6_TCLASS_MASK); + dsfield = ipv6_get_dsfield(ipv6h); + else + dsfield = ip6_tclass(t->parms.flowinfo); + if (t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL) fl6.flowlabel |= ip6_flowlabel(ipv6h); if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK) diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index 6eb2ae5..7ae6c50 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -1196,7 +1196,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield, skb_push(skb, sizeof(struct ipv6hdr)); skb_reset_network_header(skb); ipv6h = ipv6_hdr(skb); - ip6_flow_hdr(ipv6h, INET_ECN_encapsulate(0, dsfield), + ip6_flow_hdr(ipv6h, dsfield, ip6_make_flowlabel(net, skb, fl6->flowlabel, true, fl6)); ipv6h->hop_limit = hop_limit; ipv6h->nexthdr = proto; @@ -1231,8 +1231,6 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) if (tproto != IPPROTO_IPIP && tproto != 0) return -1; - dsfield = ipv4_get_dsfield(iph); - if (t->parms.collect_md) { struct ip_tunnel_info *tun_info; const struct ip_tunnel_key *key; @@ -1246,6 +1244,7 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) fl6.flowi6_proto = IPPROTO_IPIP; fl6.daddr = key->u.ipv6.dst; fl6.flowlabel = key->label; + dsfield = ip6_tclass(key->label); } else { if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT)) encap_limit = t->parms.encap_limit; @@ -1254,8 +1253,9 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) fl6.flowi6_proto = IPPROTO_IPIP; if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS) - fl6.flowlabel |= htonl((__u32)iph->tos << IPV6_TCLASS_SHIFT) - & IPV6_TCLASS_MASK; + dsfield = ipv4_get_dsfield(iph); + else + dsfield = ip6_tclass(t->parms.flowinfo); if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK) fl6.flowi6_mark = skb->mark; else @@ -1267,6 +1267,8 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6)) return -1; + dsfield = INET_ECN_encapsulate(dsfield, ipv4_get_dsfield(iph)); + skb_set_inner_ipproto(skb, IPPROTO_IPIP); err = ip6_tnl_xmit(skb, dev, dsfield, &fl6, encap_limit, &mtu, @@ -1300,8 +1302,6 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) ip6_tnl_addr_conflict(t, ipv6h)) return -1; - dsfield = ipv6_get_dsfield(ipv6h); - if (t->parms.collect_md) { struct ip_tunnel_info *tun_info; const struct ip_tunnel_key *key; @@ -1315,6 +1315,7 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) fl6.flowi6_proto = IPPROTO_IPV6; fl6.daddr = key->u.ipv6.dst; fl6.flowlabel = key->label; + dsfield = ip6_tclass(key->label); } else { offset = ip6_tnl_parse_tlv_enc_lim(skb, skb_network_header(skb)); /* ip6_tnl_parse_tlv_enc_lim() might have reallocated skb->head */ @@ -1337,7 +1338,9 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) fl6.flowi6_proto = IPPROTO_IPV6; if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS) - fl6.flowlabel |= (*(__be32 *)ipv6h & IPV6_TCLASS_MASK); + dsfield = ipv6_get_dsfield(ipv6h); + else + dsfield = ip6_tclass(t->parms.flowinfo); if (t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL) fl6.flowlabel |= ip6_flowlabel(ipv6h); if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK) @@ -1351,6 +1354,8 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6)) return -1; + dsfield = INET_ECN_encapsulate(dsfield, ipv6_get_dsfield(ipv6h)); + skb_set_inner_ipproto(skb, IPPROTO_IPV6); err = ip6_tnl_xmit(skb, dev, dsfield, &fl6, encap_limit, &mtu, -- 2.7.4