[PATCHv2 net-next 2/6] lwtunnel: add LWTUNNEL_IP_OPTS support for lwtunnel_ip

[Xin Long]

This patch is to add LWTUNNEL_IP_OPTS into lwtunnel_ip_t, by which
users will be able to set options for ip_tunnel_info by "ip route
encap" for erspan and vxlan's private metadata. Like one way to go
in iproute is:

  # ip route add 1.1.1.0/24 encap ip id 1 erspan ver 1 idx 123 \
      dst 10.1.0.2 dev erspan1
  # ip route show
    1.1.1.0/24  encap ip id 1 src 0.0.0.0 dst 10.1.0.2 ttl 0 \
      tos 0 erspan ver 1 idx 123 dev erspan1 scope link

Signed-off-by: Xin Long <lucien....@gmail.com>
---
 include/uapi/linux/lwtunnel.h |  1 +
 net/ipv4/ip_tunnel_core.c     | 30 ++++++++++++++++++++++++------
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/include/uapi/linux/lwtunnel.h b/include/uapi/linux/lwtunnel.h
index de696ca..93f2c05 100644
--- a/include/uapi/linux/lwtunnel.h
+++ b/include/uapi/linux/lwtunnel.h
@@ -27,6 +27,7 @@ enum lwtunnel_ip_t {
        LWTUNNEL_IP_TOS,
        LWTUNNEL_IP_FLAGS,
        LWTUNNEL_IP_PAD,
+       LWTUNNEL_IP_OPTS,
        __LWTUNNEL_IP_MAX,
 };
 
diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index 10f0848..d9b7188 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -218,6 +218,7 @@ static const struct nla_policy 
ip_tun_policy[LWTUNNEL_IP_MAX + 1] = {
        [LWTUNNEL_IP_TTL]       = { .type = NLA_U8 },
        [LWTUNNEL_IP_TOS]       = { .type = NLA_U8 },
        [LWTUNNEL_IP_FLAGS]     = { .type = NLA_U16 },
+       [LWTUNNEL_IP_OPTS]      = { .type = NLA_BINARY },
 };
 
 static int ip_tun_build_state(struct nlattr *attr,
@@ -228,14 +229,20 @@ static int ip_tun_build_state(struct nlattr *attr,
        struct ip_tunnel_info *tun_info;
        struct lwtunnel_state *new_state;
        struct nlattr *tb[LWTUNNEL_IP_MAX + 1];
-       int err;
+       int err, opts_len = 0;
+       void *opts;
 
        err = nla_parse_nested_deprecated(tb, LWTUNNEL_IP_MAX, attr,
                                          ip_tun_policy, extack);
        if (err < 0)
                return err;
 
-       new_state = lwtunnel_state_alloc(sizeof(*tun_info));
+       if (tb[LWTUNNEL_IP_OPTS]) {
+               opts = nla_data(tb[LWTUNNEL_IP_OPTS]);
+               opts_len = nla_len(tb[LWTUNNEL_IP_OPTS]);
+       }
+
+       new_state = lwtunnel_state_alloc(sizeof(*tun_info) + opts_len);
        if (!new_state)
                return -ENOMEM;
 
@@ -269,8 +276,10 @@ static int ip_tun_build_state(struct nlattr *attr,
        if (tb[LWTUNNEL_IP_FLAGS])
                tun_info->key.tun_flags = nla_get_be16(tb[LWTUNNEL_IP_FLAGS]);
 
+       if (opts_len)
+               ip_tunnel_info_opts_set(tun_info, opts, opts_len, 0);
+
        tun_info->mode = IP_TUNNEL_INFO_TX;
-       tun_info->options_len = 0;
 
        *ts = new_state;
 
@@ -299,6 +308,10 @@ static int ip_tun_fill_encap_info(struct sk_buff *skb,
            nla_put_u8(skb, LWTUNNEL_IP_TTL, tun_info->key.ttl) ||
            nla_put_be16(skb, LWTUNNEL_IP_FLAGS, tun_info->key.tun_flags))
                return -ENOMEM;
+       if (tun_info->options_len &&
+           nla_put(skb, LWTUNNEL_IP_OPTS,
+                   tun_info->options_len, ip_tunnel_info_opts(tun_info)))
+               return -ENOMEM;
 
        return 0;
 }
@@ -310,13 +323,18 @@ static int ip_tun_encap_nlsize(struct lwtunnel_state 
*lwtstate)
                + nla_total_size(4)     /* LWTUNNEL_IP_SRC */
                + nla_total_size(1)     /* LWTUNNEL_IP_TOS */
                + nla_total_size(1)     /* LWTUNNEL_IP_TTL */
-               + nla_total_size(2);    /* LWTUNNEL_IP_FLAGS */
+               + nla_total_size(2)     /* LWTUNNEL_IP_FLAGS */
+               + lwt_tun_info(lwtstate)->options_len;  /* LWTUNNEL_IP_OPTS */
 }
 
 static int ip_tun_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
 {
-       return memcmp(lwt_tun_info(a), lwt_tun_info(b),
-                     sizeof(struct ip_tunnel_info));
+       struct ip_tunnel_info *info_a = lwt_tun_info(a);
+       struct ip_tunnel_info *info_b = lwt_tun_info(b);
+       u8 opts_len;
+
+       opts_len = min(info_a->options_len, info_b->options_len);
+       return memcmp(info_a, info_b, sizeof(*info_a) + opts_len);
 }
 
 static const struct lwtunnel_encap_ops ip_tun_lwt_ops = {
-- 
2.1.0