gre: Resolve gre receive issues

On newer Linux kernels or on older kernels such as Red Hat that backport
from newer upstream Linux kernel releases the built-in gre kernel module
will interfere with OVS gre code in the receive path.  Fix this up by
placing the gre kernel code within the openvswitch driver so it will
not have to depend on the built-in gre kernel module.

Signed-off-by: Greg Rose <gvrose8192@gmail.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: William Tu <u9012063@gmail.com>

diff --git a/datapath/linux/compat/gre.c b/datapath/linux/compat/gre.c
index 7d16aeed54fb4323c2b900bd04df294397332791..b45f8b4597e6b56aa862bad88931fbe03539f31c 100644 (file)
--- a/datapath/linux/compat/gre.c
+++ b/datapath/linux/compat/gre.c
@@ -41,6 +41,104 @@
 #ifndef USE_UPSTREAM_TUNNEL
 #if IS_ENABLED(CONFIG_NET_IPGRE_DEMUX)
 
+static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;
+
+int rpl_gre_add_protocol(const struct gre_protocol *proto, u8 version)
+{
+       if (version >= GREPROTO_MAX)
+               return -EINVAL;
+
+       return (cmpxchg((const struct gre_protocol **)&gre_proto[version], NULL, proto) == NULL) ?
+               0 : -EBUSY;
+}
+EXPORT_SYMBOL_GPL(rpl_gre_add_protocol);
+
+int rpl_gre_del_protocol(const struct gre_protocol *proto, u8 version)
+{
+       int ret;
+
+       if (version >= GREPROTO_MAX)
+               return -EINVAL;
+
+       ret = (cmpxchg((const struct gre_protocol **)&gre_proto[version], proto, NULL) == proto) ?
+               0 : -EBUSY;
+
+       if (ret)
+               return ret;
+
+       synchronize_rcu();
+       return 0;
+}
+EXPORT_SYMBOL_GPL(rpl_gre_del_protocol);
+
+static int gre_rcv(struct sk_buff *skb)
+{
+       const struct gre_protocol *proto;
+       u8 ver;
+       int ret;
+
+       if (!pskb_may_pull(skb, 12))
+               goto drop;
+
+       ver = skb->data[1]&0x7f;
+       if (ver >= GREPROTO_MAX)
+               goto drop;
+
+       rcu_read_lock();
+       proto = rcu_dereference(gre_proto[ver]);
+       if (!proto || !proto->handler)
+               goto drop_unlock;
+       ret = proto->handler(skb);
+       rcu_read_unlock();
+       return ret;
+
+drop_unlock:
+       rcu_read_unlock();
+drop:
+       kfree_skb(skb);
+       return NET_RX_DROP;
+}
+
+static void gre_err(struct sk_buff *skb, u32 info)
+{
+       const struct gre_protocol *proto;
+       const struct iphdr *iph = (const struct iphdr *)skb->data;
+       u8 ver = skb->data[(iph->ihl<<2) + 1]&0x7f;
+
+       if (ver >= GREPROTO_MAX)
+               return;
+
+       rcu_read_lock();
+       proto = rcu_dereference(gre_proto[ver]);
+       if (proto && proto->err_handler)
+               proto->err_handler(skb, info);
+       rcu_read_unlock();
+}
+
+static const struct net_protocol net_gre_protocol = {
+       .handler     = gre_rcv,
+       .err_handler = gre_err,
+       .netns_ok    = 1,
+};
+
+int rpl_gre_init(void)
+{
+       pr_info("GRE over IPv4 demultiplexor driver\n");
+
+       if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
+               pr_err("can't add protocol\n");
+               return -EAGAIN;
+       }
+       return 0;
+}
+EXPORT_SYMBOL_GPL(rpl_gre_init);
+
+void rpl_gre_exit(void)
+{
+       inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
+}
+EXPORT_SYMBOL_GPL(rpl_gre_exit);
+
 #define ip_gre_calc_hlen rpl_ip_gre_calc_hlen
 #define gre_calc_hlen rpl_ip_gre_calc_hlen
 static int rpl_ip_gre_calc_hlen(__be16 o_flags)
@@ -142,25 +240,20 @@ static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
        return iptunnel_pull_header(skb, hdr_len, tpi->proto, false);
 }
 
-#endif /* HAVE_DEMUX_PARSE_GRE_HEADER */
-
 static struct gre_cisco_protocol __rcu *gre_cisco_proto;
 static int gre_cisco_rcv(struct sk_buff *skb)
 {
-       struct tnl_ptk_info tpi;
        struct gre_cisco_protocol *proto;
+       struct tnl_ptk_info tpi;
+       bool csum_err = false;
 
        rcu_read_lock();
        proto = rcu_dereference(gre_cisco_proto);
        if (!proto)
                goto drop;
-#ifdef HAVE_DEMUX_PARSE_GRE_HEADER
-       {
-               bool csum_err = false;
-               if (parse_gre_header(skb, &tpi, &csum_err) < 0)
+
+       if (parse_gre_header(skb, &tpi, &csum_err) < 0)
                        goto drop;
-       }
-#endif
        proto->handler(skb, &tpi);
        rcu_read_unlock();
        return 0;
@@ -194,7 +287,6 @@ EXPORT_SYMBOL_GPL(rpl_gre_cisco_register);
 int rpl_gre_cisco_unregister(struct gre_cisco_protocol *proto)
 {
        int ret;
-
        ret = (cmpxchg((struct gre_cisco_protocol **)&gre_cisco_proto, proto, NULL) == proto) ?
                0 : -EINVAL;
 
@@ -207,6 +299,7 @@ int rpl_gre_cisco_unregister(struct gre_cisco_protocol *proto)
 }
 EXPORT_SYMBOL_GPL(rpl_gre_cisco_unregister);
 
+#endif /* HAVE_DEMUX_PARSE_GRE_HEADER */
 #endif /* !HAVE_GRE_CISCO_REGISTER */
 #endif
 

diff --git a/datapath/linux/compat/include/net/gre.h b/datapath/linux/compat/include/net/gre.h
index 11a95a56933190083e8b01e1eb15eaf0a26aff13..141ed2d9cec29ed3148e54ac428977e2741e6bf7 100644 (file)
--- a/datapath/linux/compat/include/net/gre.h
+++ b/datapath/linux/compat/include/net/gre.h
@@ -32,6 +32,15 @@ static inline void rpl_ip6_tunnel_cleanup(void)
 {
 }
 
+static inline int rpl_gre_init(void)
+{
+       return 0;
+}
+
+static inline void rpl_gre_exit(void)
+{
+}
+
 #define gre_fb_xmit dev_queue_xmit
 
 #ifdef CONFIG_INET
@@ -153,6 +162,8 @@ int rpl_ip6gre_init(void);
 void rpl_ip6gre_fini(void);
 int rpl_ip6_tunnel_init(void);
 void rpl_ip6_tunnel_cleanup(void);
+int rpl_gre_init(void);
+void rpl_gre_exit(void);
 
 #define gretap_fb_dev_create rpl_gretap_fb_dev_create
 struct net_device *rpl_gretap_fb_dev_create(struct net *net, const char *name,
@@ -164,6 +175,11 @@ int rpl_gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 
 #define gre_fb_xmit rpl_gre_fb_xmit
 netdev_tx_t rpl_gre_fb_xmit(struct sk_buff *skb);
+
+#define gre_add_protocol rpl_gre_add_protocol
+int rpl_gre_add_protocol(const struct gre_protocol *proto, u8 version);
+#define gre_del_protocol rpl_gre_del_protocol
+int rpl_gre_del_protocol(const struct gre_protocol *proto, u8 version);
 #endif /* USE_UPSTREAM_TUNNEL */
 
 #define ipgre_init rpl_ipgre_init
@@ -172,6 +188,8 @@ netdev_tx_t rpl_gre_fb_xmit(struct sk_buff *skb);
 #define ip6gre_fini rpl_ip6gre_fini
 #define ip6_tunnel_init rpl_ip6_tunnel_init
 #define ip6_tunnel_cleanup rpl_ip6_tunnel_cleanup
+#define gre_init rpl_gre_init
+#define gre_exit rpl_gre_exit
 
 #define gre_fill_metadata_dst ovs_gre_fill_metadata_dst
 int ovs_gre_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb);

diff --git a/datapath/linux/compat/ip_gre.c b/datapath/linux/compat/ip_gre.c
index eecd41ae1e5001236a5e83f9c9196565c29aab9e..9240ab2eab6bdff0c8abf4adea54a3beb3973ec0 100644 (file)
--- a/datapath/linux/compat/ip_gre.c
+++ b/datapath/linux/compat/ip_gre.c
@@ -96,13 +96,14 @@ static __be32 tunnel_id_to_key(__be64 x)
 #endif
 }
 
+#ifdef HAVE_DEMUX_PARSE_GRE_HEADER
 /* Called with rcu_read_lock and BH disabled. */
 static int gre_err(struct sk_buff *skb, u32 info,
                   const struct tnl_ptk_info *tpi)
 {
        return PACKET_REJECT;
 }
-
+#endif
 static struct dst_ops md_dst_ops = {
        .family =               AF_UNSPEC,
 };
@@ -746,11 +747,28 @@ static void __gre_tunnel_init(struct net_device *dev)
        }
 }
 
-static struct gre_cisco_protocol ipgre_protocol = {
+#ifdef HAVE_DEMUX_PARSE_GRE_HEADER
+static struct gre_cisco_protocol ipgre_cisco_protocol = {
        .handler        = gre_rcv,
        .err_handler    = gre_err,
        .priority       = 1,
 };
+#endif
+
+static int __gre_rcv(struct sk_buff *skb)
+{
+       return gre_rcv(skb, NULL);
+}
+
+void __gre_err(struct sk_buff *skb, u32 info)
+{
+       pr_warn("%s: GRE receive error\n", __func__);
+}
+
+static const struct gre_protocol ipgre_protocol = {
+       .handler     = __gre_rcv,
+       .err_handler = __gre_err,
+};
 
 static int __net_init ipgre_init_net(struct net *net)
 {
@@ -1631,11 +1649,19 @@ int rpl_ipgre_init(void)
        if (err < 0)
                goto pnet_ipgre_failed;
 
-       err = gre_cisco_register(&ipgre_protocol);
+#ifdef HAVE_DEMUX_PARSE_GRE_HEADER
+       err = gre_cisco_register(&ipgre_cisco_protocol);
        if (err < 0) {
                pr_info("%s: can't add protocol\n", __func__);
                goto add_proto_failed;
        }
+#else
+       err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO);
+       if (err < 0) {
+               pr_info("%s: can't add protocol\n", __func__);
+               goto add_proto_failed;
+       }
+#endif
 
        pr_info("GRE over IPv4 tunneling driver\n");
        
@@ -1658,7 +1684,11 @@ void rpl_ipgre_fini(void)
 {
        ovs_vport_ops_unregister(&ovs_erspan_vport_ops);
        ovs_vport_ops_unregister(&ovs_ipgre_vport_ops);
-       gre_cisco_unregister(&ipgre_protocol);
+#ifdef HAVE_DEMUX_PARSE_GRE_HEADER
+       gre_cisco_unregister(&ipgre_cisco_protocol);
+#else
+       gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
+#endif
        unregister_pernet_device(&ipgre_net_ops);
        unregister_pernet_device(&erspan_net_ops);
        unregister_pernet_device(&ipgre_tap_net_ops);

diff --git a/datapath/vport.c b/datapath/vport.c
index 184c8593e3fd4bcbf0d42c0a9e68e8c7d24ff98f..73dd7783c241fa02cee69662dc31684e2ae198f6 100644 (file)
--- a/datapath/vport.c
+++ b/datapath/vport.c
@@ -66,7 +66,7 @@ int ovs_vport_init(void)
                goto err_lisp;
        err = ipgre_init();
        if (err)
-               goto err_gre;
+               goto err_ipgre;
        err = ip6gre_init();
        if (err)
                goto err_ip6gre;
@@ -76,15 +76,19 @@ int ovs_vport_init(void)
        err = geneve_init_module();
        if (err)
                goto err_geneve;
-
        err = vxlan_init_module();
        if (err)
                goto err_vxlan;
        err = ovs_stt_init_module();
        if (err)
                goto err_stt;
-       return 0;
+       err = gre_init();
+       if (err)
+               goto err_gre;
 
+       return 0;
+err_gre:
+       ovs_stt_cleanup_module();
 err_stt:
        vxlan_cleanup_module();
 err_vxlan:
@@ -95,7 +99,7 @@ err_ip6_tunnel:
        ip6gre_fini();
 err_ip6gre:
        ipgre_fini();
-err_gre:
+err_ipgre:
        lisp_cleanup_module();
 err_lisp:
        kfree(dev_table);
@@ -109,6 +113,7 @@ err_lisp:
  */
 void ovs_vport_exit(void)
 {
+       gre_exit();
        ovs_stt_cleanup_module();
        vxlan_cleanup_module();
        geneve_cleanup_module();