On 02/06/15 01:06, Thomas Graf wrote:
On 06/01/15 at 05:46pm, Robert Shearman wrote:
In order to be able to function as a Label Edge Router in an MPLS
network, it is necessary to be able to take IP packets and impose an
MPLS encap and forward them out. The traditional approach of setting
up an interface for each "tunnel" endpoint doesn't scale for the
common MPLS use-cases where each IP route tends to be assigned a
different label as encap.
The solution suggested here for further discussion is to provide the
facility to define encap data on a per-nexthop basis using a new
netlink attribue, RTA_ENCAP, which would be opaque to the IPv4/IPv6
forwarding code, but interpreted by the virtual interface assigned to
the nexthop.
RTA_ENCAP is currently a binary blob specific to each encapsulation
type interface. I guess this should be converted to a set of nested
Netlink attributes for each type of encap to make it extendible in
the future.
Nesting attributes inside the RTA_ENCAP blob should be supported by the
patch series today. Something like this:
+enum rta_tunnel_t {
+ RTA_TUN_UNSPEC,
+ RTA_TUN_ID,
+ RTA_TUN_DST,
+ RTA_TUN_SRC,
+ RTA_TUN_TTL,
+ RTA_TUN_TOS,
+ RTA_TUN_SPORT,
+ RTA_TUN_DPORT,
+ RTA_TUN_FLAGS,
+ RTA_TUN_MAX,
+};
+
+static const struct nla_policy tunnel_policy[RTA_TUN_MAX + 1] = {
+ [RTA_TUN_ID] = { .type = NLA_U64 },
+ [RTA_TUN_DST] = { .type = NLA_U32 },
+ [RTA_TUN_SRC] = { .type = NLA_U32 },
+ [RTA_TUN_TTL] = { .type = NLA_U8 },
+ [RTA_TUN_TOS] = { .type = NLA_U8 },
+ [RTA_TUN_SPORT] = { .type = NLA_U16 },
+ [RTA_TUN_DPORT] = { .type = NLA_U16 },
+ [RTA_TUN_FLAGS] = { .type = NLA_U16 },
+};
+
+static int vxlan_parse_encap(const struct net_device *dev,
+ const struct nlattr *nla,
+ void *encap)
+{
+ if (encap) {
+ struct ip_tunnel_info *tun_info = encap;
+ struct nlattr *tb[RTA_TUN_MAX+1];
+ int err;
+
+ err = nla_parse_nested(tb, RTA_TUN_MAX, nla, tunnel_policy);
+ if (err < 0)
+ return err;
+
+ if (tb[RTA_TUN_ID])
+ tun_info->key.tun_id = nla_get_u64(tb[RTA_TUN_ID]);
+
+ if (tb[RTA_TUN_DST])
+ tun_info->key.ipv4_dst = nla_get_be32(tb[RTA_TUN_DST]);
+
+ if (tb[RTA_TUN_SRC])
+ tun_info->key.ipv4_src = nla_get_be32(tb[RTA_TUN_SRC]);
+
+ if (tb[RTA_TUN_TTL])
+ tun_info->key.ipv4_ttl = nla_get_u8(tb[RTA_TUN_TTL]);
+
+ if (tb[RTA_TUN_TOS])
+ tun_info->key.ipv4_tos = nla_get_u8(tb[RTA_TUN_TOS]);
+
+ if (tb[RTA_TUN_SPORT])
+ tun_info->key.tp_src = nla_get_be16(tb[RTA_TUN_SPORT]);
+
+ if (tb[RTA_TUN_DPORT])
+ tun_info->key.tp_dst = nla_get_be16(tb[RTA_TUN_DPORT]);
+
+ if (tb[RTA_TUN_FLAGS])
+ tun_info->key.tun_flags =
nla_get_u16(tb[RTA_TUN_FLAGS]);
+
+ tun_info->options = NULL;
+ tun_info->options_len = 0;
+ }
+
+ return sizeof(struct ip_tunnel_info);
+}
+
+static int vxlan_fill_encap(const struct net_device *dev,
+ struct sk_buff *skb, int encap_len,
+ const void *encap)
+{
+ const struct ip_tunnel_info *tun_info = encap;
+ struct nlattr *encap_attr;
+
+ encap_attr = nla_nest_start(skb, RTA_ENCAP);
+ if (!encap_attr)
+ return -ENOMEM;
+
+ if (nla_put_u64(skb, RTA_TUN_ID, tun_info->key.tun_id) ||
+ nla_put_be32(skb, RTA_TUN_DST, tun_info->key.ipv4_dst) ||
+ nla_put_be32(skb, RTA_TUN_SRC, tun_info->key.ipv4_src) ||
+ nla_put_u8(skb, RTA_TUN_TOS, tun_info->key.ipv4_tos) ||
+ nla_put_u8(skb, RTA_TUN_TTL, tun_info->key.ipv4_ttl) ||
+ nla_put_u16(skb, RTA_TUN_SPORT, tun_info->key.tp_src) ||
+ nla_put_u16(skb, RTA_TUN_DPORT, tun_info->key.tp_dst) ||
+ nla_put_u16(skb, RTA_TUN_FLAGS, tun_info->key.tun_flags))
+ return -ENOMEM;
+
+ nla_nest_end(skb, encap_attr);
+
+ return 0;
+}
+
+static int vxlan_match_encap(const struct net_device *dev,
+ const struct nlattr *nla, int encap_len,
+ const void *encap)
+{
+ const struct ip_tunnel_info *tun_info = encap;
+ struct nlattr *tb[RTA_TUN_MAX+1];
+ int err;
+
+ err = nla_parse_nested(tb, RTA_TUN_MAX, nla, tunnel_policy);
+ if (err < 0)
+ return err;
+
+ if (tb[RTA_TUN_ID] &&
+ tun_info->key.tun_id != nla_get_u64(tb[RTA_TUN_ID]))
+ return 1;
+
+ if (tb[RTA_TUN_DST] &&
+ tun_info->key.ipv4_dst != nla_get_be32(tb[RTA_TUN_DST]))
+ return 1;
+
+ if (tb[RTA_TUN_SRC] &&
+ tun_info->key.ipv4_src != nla_get_be32(tb[RTA_TUN_SRC]))
+ return 1;
+
+ if (tb[RTA_TUN_TTL] &&
+ tun_info->key.ipv4_ttl != nla_get_u8(tb[RTA_TUN_TTL]))
+ return 1;
+
+ if (tb[RTA_TUN_TOS] &&
+ tun_info->key.ipv4_tos != nla_get_u8(tb[RTA_TUN_TOS]))
+ return 1;
+
+ if (tb[RTA_TUN_SPORT] &&
+ tun_info->key.tp_src != nla_get_be16(tb[RTA_TUN_SPORT]))
+ return 1;
+
+ if (tb[RTA_TUN_DPORT] &&
+ tun_info->key.tp_dst != nla_get_be16(tb[RTA_TUN_DPORT]))
+ return 1;
+
+ if (tb[RTA_TUN_FLAGS] &&
+ tun_info->key.tun_flags != nla_get_u16(tb[RTA_TUN_FLAGS]))
+ return 1;
+
+ return 0;
+}
+
static struct rtnl_link_ops vxlan_link_ops __read_mostly = {
.kind = "vxlan",
.maxtype = IFLA_VXLAN_MAX,
@@ -2893,6 +3093,9 @@ static struct rtnl_link_ops vxlan_link_ops
__read_mostly = {
.get_size = vxlan_get_size,
.fill_info = vxlan_fill_info,
.get_link_net = vxlan_get_link_net,
+ .parse_encap = vxlan_parse_encap,
+ .fill_encap = vxlan_fill_encap,
+ .match_encap = vxlan_match_encap,
};
What is your plan regarding the receive side and on the matching of
encap fields? Storing the receive parameters is what lead me to
storing it in skb_shared_info.
No plan for the receive side and it wouldn't easily fit in with my
approach, so you'll need to implement that separately.
Thanks,
Rob
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