mpls: allow TTL propagation from IP packets to be configured

[linux-2.6-block.git] / net / mpls / mpls_iptunnel.c

diff --git a/net/mpls/mpls_iptunnel.c b/net/mpls/mpls_iptunnel.c
index e4e4424f9eb1f5531d22463687d74c2e2ca971a6..22f71fce0bfb85a6a9f1f30d171dd141609653ab 100644 (file)
--- 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++)