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authorRobert Shearman <rshearma@brocade.com>2017-03-10 20:43:25 +0000
committerDavid S. Miller <davem@davemloft.net>2017-03-13 15:29:22 -0700
commita59166e470868d92f0813977817e99e699398af5 (patch)
treef048a169201c566cd931aa29d17b0ce75c79e2aa /net/mpls/mpls_iptunnel.c
parent5b441ac8784c1e7f3c619f14da4c3f52e87348d5 (diff)
downloadlinux-stericsson-a59166e470868d92f0813977817e99e699398af5.tar.gz
mpls: allow TTL propagation from IP packets to be configured
Allow TTL propagation from IP packets to MPLS packets to be configured. Add a new optional LWT attribute, MPLS_IPTUNNEL_TTL, which allows the TTL to be set in the resulting MPLS packet, with the value of 0 having the semantics of enabling propagation of the TTL from the IP header (i.e. non-zero values disable propagation). Also allow the configuration to be overridden globally by reusing the same sysctl to control whether the TTL is propagated from IP packets into the MPLS header. If the per-LWT attribute is set then it overrides the global configuration. If the TTL isn't propagated then a default TTL value is used which can be configured via a new sysctl, "net.mpls.default_ttl". This is kept separate from the configuration of whether IP TTL propagation is enabled as it can be used in the future when non-IP payloads are supported (i.e. where there is no payload TTL that can be propagated). Signed-off-by: Robert Shearman <rshearma@brocade.com> Acked-by: David Ahern <dsa@cumulusnetworks.com> Tested-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/mpls/mpls_iptunnel.c')
-rw-r--r--net/mpls/mpls_iptunnel.c73
1 files changed, 60 insertions, 13 deletions
diff --git a/net/mpls/mpls_iptunnel.c b/net/mpls/mpls_iptunnel.c
index e4e4424f9eb1..22f71fce0bfb 100644
--- a/net/mpls/mpls_iptunnel.c
+++ b/net/mpls/mpls_iptunnel.c
@@ -29,6 +29,7 @@
static const struct nla_policy mpls_iptunnel_policy[MPLS_IPTUNNEL_MAX + 1] = {
[MPLS_IPTUNNEL_DST] = { .type = NLA_U32 },
+ [MPLS_IPTUNNEL_TTL] = { .type = NLA_U8 },
};
static unsigned int mpls_encap_size(struct mpls_iptunnel_encap *en)
@@ -49,6 +50,7 @@ static int mpls_xmit(struct sk_buff *skb)
struct rtable *rt = NULL;
struct rt6_info *rt6 = NULL;
struct mpls_dev *out_mdev;
+ struct net *net;
int err = 0;
bool bos;
int i;
@@ -56,17 +58,7 @@ static int mpls_xmit(struct sk_buff *skb)
/* Find the output device */
out_dev = dst->dev;
-
- /* Obtain the ttl */
- if (dst->ops->family == AF_INET) {
- ttl = ip_hdr(skb)->ttl;
- rt = (struct rtable *)dst;
- } else if (dst->ops->family == AF_INET6) {
- ttl = ipv6_hdr(skb)->hop_limit;
- rt6 = (struct rt6_info *)dst;
- } else {
- goto drop;
- }
+ net = dev_net(out_dev);
skb_orphan(skb);
@@ -78,6 +70,38 @@ static int mpls_xmit(struct sk_buff *skb)
tun_encap_info = mpls_lwtunnel_encap(dst->lwtstate);
+ /* Obtain the ttl using the following set of rules.
+ *
+ * LWT ttl propagation setting:
+ * - disabled => use default TTL value from LWT
+ * - enabled => use TTL value from IPv4/IPv6 header
+ * - default =>
+ * Global ttl propagation setting:
+ * - disabled => use default TTL value from global setting
+ * - enabled => use TTL value from IPv4/IPv6 header
+ */
+ if (dst->ops->family == AF_INET) {
+ if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DISABLED)
+ ttl = tun_encap_info->default_ttl;
+ else if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DEFAULT &&
+ !net->mpls.ip_ttl_propagate)
+ ttl = net->mpls.default_ttl;
+ else
+ ttl = ip_hdr(skb)->ttl;
+ rt = (struct rtable *)dst;
+ } else if (dst->ops->family == AF_INET6) {
+ if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DISABLED)
+ ttl = tun_encap_info->default_ttl;
+ else if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DEFAULT &&
+ !net->mpls.ip_ttl_propagate)
+ ttl = net->mpls.default_ttl;
+ else
+ ttl = ipv6_hdr(skb)->hop_limit;
+ rt6 = (struct rt6_info *)dst;
+ } else {
+ goto drop;
+ }
+
/* Verify the destination can hold the packet */
new_header_size = mpls_encap_size(tun_encap_info);
mtu = mpls_dev_mtu(out_dev);
@@ -160,6 +184,17 @@ static int mpls_build_state(struct nlattr *nla,
&tun_encap_info->labels, tun_encap_info->label);
if (ret)
goto errout;
+
+ tun_encap_info->ttl_propagate = MPLS_TTL_PROP_DEFAULT;
+
+ if (tb[MPLS_IPTUNNEL_TTL]) {
+ tun_encap_info->default_ttl = nla_get_u8(tb[MPLS_IPTUNNEL_TTL]);
+ /* TTL 0 implies propagate from IP header */
+ tun_encap_info->ttl_propagate = tun_encap_info->default_ttl ?
+ MPLS_TTL_PROP_DISABLED :
+ MPLS_TTL_PROP_ENABLED;
+ }
+
newts->type = LWTUNNEL_ENCAP_MPLS;
newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT;
newts->headroom = mpls_encap_size(tun_encap_info);
@@ -186,6 +221,10 @@ static int mpls_fill_encap_info(struct sk_buff *skb,
tun_encap_info->label))
goto nla_put_failure;
+ if (tun_encap_info->ttl_propagate != MPLS_TTL_PROP_DEFAULT &&
+ nla_put_u8(skb, MPLS_IPTUNNEL_TTL, tun_encap_info->default_ttl))
+ goto nla_put_failure;
+
return 0;
nla_put_failure:
@@ -195,10 +234,16 @@ nla_put_failure:
static int mpls_encap_nlsize(struct lwtunnel_state *lwtstate)
{
struct mpls_iptunnel_encap *tun_encap_info;
+ int nlsize;
tun_encap_info = mpls_lwtunnel_encap(lwtstate);
- return nla_total_size(tun_encap_info->labels * 4);
+ nlsize = nla_total_size(tun_encap_info->labels * 4);
+
+ if (tun_encap_info->ttl_propagate != MPLS_TTL_PROP_DEFAULT)
+ nlsize += nla_total_size(1);
+
+ return nlsize;
}
static int mpls_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
@@ -207,7 +252,9 @@ static int mpls_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
struct mpls_iptunnel_encap *b_hdr = mpls_lwtunnel_encap(b);
int l;
- if (a_hdr->labels != b_hdr->labels)
+ if (a_hdr->labels != b_hdr->labels ||
+ a_hdr->ttl_propagate != b_hdr->ttl_propagate ||
+ a_hdr->default_ttl != b_hdr->default_ttl)
return 1;
for (l = 0; l < MAX_NEW_LABELS; l++)