Like tos inherit, ttl inherit should also means inherit the inner protocol's
ttl values, which actually not implemented in vxlan yet.
But we could not treat ttl == 0 as "use the inner TTL", because that would be
used also when the "ttl" option is not specified and that would be a behavior
change, and breaking real use cases.
So add a different attribute IFLA_VXLAN_TTL_INHERIT when "ttl inherit" is
specified with ip cmd.
Reported-by: Jianlin Shi <ji...@redhat.com>
Suggested-by: Jiri Benc <jb...@redhat.com>
Signed-off-by: Hangbin Liu <liuhang...@gmail.com>
---
drivers/net/vxlan.c | 17 ++++++++++++++---
include/net/ip_tunnels.h | 11 +++++++++++
include/net/vxlan.h | 1 +
include/uapi/linux/if_link.h | 1 +
4 files changed, 27 insertions(+), 3 deletions(-)
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index aa5f034..209a840 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2085,9 +2085,13 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct
net_device *dev,
local_ip = vxlan->cfg.saddr;
dst_cache = &rdst->dst_cache;
md->gbp = skb->mark;
- ttl = vxlan->cfg.ttl;
- if (!ttl && vxlan_addr_multicast(dst))
- ttl = 1;
+ if (flags & VXLAN_F_TTL_INHERIT) {
+ ttl = ip_tunnel_get_ttl(old_iph, skb);
+ } else {
+ ttl = vxlan->cfg.ttl;
+ if (!ttl && vxlan_addr_multicast(dst))
+ ttl = 1;
+ }
tos = vxlan->cfg.tos;
if (tos == 1)
@@ -2709,6 +2713,7 @@ static const struct nla_policy
vxlan_policy[IFLA_VXLAN_MAX + 1] = {
[IFLA_VXLAN_GBP] = { .type = NLA_FLAG, },
[IFLA_VXLAN_GPE] = { .type = NLA_FLAG, },
[IFLA_VXLAN_REMCSUM_NOPARTIAL] = { .type = NLA_FLAG },
+ [IFLA_VXLAN_TTL_INHERIT] = { .type = NLA_FLAG },
};
static int vxlan_validate(struct nlattr *tb[], struct nlattr *data[],
@@ -3254,6 +3259,12 @@ static int vxlan_nl2conf(struct nlattr *tb[], struct
nlattr *data[],
if (data[IFLA_VXLAN_TTL])
conf->ttl = nla_get_u8(data[IFLA_VXLAN_TTL]);
+ if (data[IFLA_VXLAN_TTL_INHERIT]) {
+ if (changelink)
+ return -EOPNOTSUPP;
+ conf->flags |= VXLAN_F_TTL_INHERIT;
+ }
+
if (data[IFLA_VXLAN_LABEL])
conf->label = nla_get_be32(data[IFLA_VXLAN_LABEL]) &
IPV6_FLOWLABEL_MASK;
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index cbe5add..6c3c421 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -377,6 +377,17 @@ static inline u8 ip_tunnel_get_dsfield(const struct iphdr
*iph,
return 0;
}
+static inline u8 ip_tunnel_get_ttl(const struct iphdr *iph,
+ const struct sk_buff *skb)
+{
+ if (skb->protocol == htons(ETH_P_IP))
+ return iph->ttl;
+ else if (skb->protocol == htons(ETH_P_IPV6))
+ return ((const struct ipv6hdr *)iph)->hop_limit;
+ else
+ return 0;
+}
+
/* Propogate ECN bits out */
static inline u8 ip_tunnel_ecn_encap(u8 tos, const struct iphdr *iph,
const struct sk_buff *skb)
diff --git a/include/net/vxlan.h b/include/net/vxlan.h
index ad73d8b..b99a02ae 100644
--- a/include/net/vxlan.h
+++ b/include/net/vxlan.h
@@ -262,6 +262,7 @@ struct vxlan_dev {
#define VXLAN_F_COLLECT_METADATA 0x2000
#define VXLAN_F_GPE 0x4000
#define VXLAN_F_IPV6_LINKLOCAL 0x8000
+#define VXLAN_F_TTL_INHERIT 0x10000
/* Flags that are used in the receive path. These flags must match in
* order for a socket to be shareable
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 11d0c0e..e771a63 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -516,6 +516,7 @@ enum {
IFLA_VXLAN_COLLECT_METADATA,
IFLA_VXLAN_LABEL,
IFLA_VXLAN_GPE,
+ IFLA_VXLAN_TTL_INHERIT,
__IFLA_VXLAN_MAX
};
#define IFLA_VXLAN_MAX (__IFLA_VXLAN_MAX - 1)
--
2.5.5
