From 72f6d71e491e6ce269b564865b21fab0a4402dd3 Mon Sep 17 00:00:00 2001 From: Hangbin Liu Date: Tue, 17 Apr 2018 14:11:28 +0800 Subject: [PATCH] vxlan: add ttl inherit support 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 Suggested-by: Jiri Benc Signed-off-by: Hangbin Liu Signed-off-by: David S. Miller --- 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 fab7a4db249e..aee0e60471f1 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 540a4b4417bf..751646adc769 100644 --- a/include/net/ip_tunnels.h +++ b/include/net/ip_tunnels.h @@ -379,6 +379,17 @@ 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 ad73d8b3fcc2..b99a02ae3934 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 68699f654118..b85266420bfb 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)