Re: [net-next 02/10] udp: Expand UDP tunnel common APIs

Added create_udp_tunnel_socket(), packet receive and transmit,  and
other related common functions for UDP tunnels.

Per net open UDP tunnel ports are tracked in this common layer to
prevent sharing of a single port with more than one UDP tunnel.

Signed-off-by: Andy Zhou <redacted>
---
 include/net/udp_tunnel.h |   57 +++++++++-
 net/ipv4/udp_tunnel.c    |  257 +++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 312 insertions(+), 2 deletions(-)

diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
index 3f34c65..b5e815a 100644
--- a/include/net/udp_tunnel.h
+++ b/include/net/udp_tunnel.h

@@ -1,7 +1,10 @@
 #ifndef __NET_UDP_TUNNEL_H
 #define __NET_UDP_TUNNEL_H

-#define UDP_TUNNEL_TYPE_VXLAN 0x01
+#include <net/ip_tunnels.h>
+
+#define UDP_TUNNEL_TYPE_VXLAN  0x01
+#define UDP_TUNNEL_TYPE_GENEVE 0x02

 struct udp_port_cfg {
        u8                      family;

@@ -28,7 +31,59 @@ struct udp_port_cfg {
                                use_udp6_rx_checksums:1;
 };

+struct udp_tunnel_sock;
+
+typedef void (udp_tunnel_rcv_t)(struct udp_tunnel_sock *uts,
+                               struct sk_buff *skb, ...);
+
+typedef int (udp_tunnel_encap_rcv_t)(struct sock *sk, struct sk_buff *skb);
+
+struct udp_tunnel_socket_cfg {
+       u8 tunnel_type;
+       struct udp_port_cfg port;
+       udp_tunnel_rcv_t *rcv;
+       udp_tunnel_encap_rcv_t *encap_rcv;

+};
+
+struct udp_tunnel_sock {
+       u8 tunnel_type;
+       struct hlist_node hlist;
+       udp_tunnel_rcv_t *rcv;
+       void *data;
+       struct socket *sock;
+};
+
 int udp_sock_create(struct net *net, struct udp_port_cfg *cfg,
                    struct socket **sockp);

+struct udp_tunnel_sock *create_udp_tunnel_socket(struct net *net, size_t size,
+                                                struct udp_tunnel_socket_cfg
+                                                       *socket_cfg);
+
+struct udp_tunnel_sock *udp_tunnel_find_sock(struct net *net, __be16 port);
+
+int udp_tunnel_xmit_skb(struct socket *sock, struct rtable *rt,
+                       struct sk_buff *skb, __be32 src, __be32 dst,
+                       __u8 tos, __u8 ttl, __be16 df, __be16 src_port,
+                       __be16 dst_port, bool xnet);
+
+#if IS_ENABLED(CONFIG_IPV6)
+int udp_tunnel6_xmit_skb(struct socket *sock, struct dst_entry *dst,
+               struct sk_buff *skb, struct net_device *dev,
+               struct in6_addr *saddr, struct in6_addr *daddr,
+               __u8 prio, __u8 ttl, __be16 src_port, __be16 dst_port);
+
+#endif
+
+void udp_tunnel_sock_release(struct udp_tunnel_sock *uts);
+void udp_tunnel_get_rx_port(struct net_device *dev);
+
+static inline struct sk_buff *udp_tunnel_handle_offloads(struct sk_buff *skb,
+                                                        bool udp_csum)
+{
+       int type = udp_csum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
+
+       return iptunnel_handle_offloads(skb, udp_csum, type);
+}
 #endif

diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel.c
index 61ec1a6..3c14b16 100644
--- a/net/ipv4/udp_tunnel.c
+++ b/net/ipv4/udp_tunnel.c

@@ -7,6 +7,23 @@
 #include <net/udp.h>
 #include <net/udp_tunnel.h>
 #include <net/net_namespace.h>
+#include <net/netns/generic.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/ipv6.h>
+#include <net/addrconf.h>
+#include <net/ip6_tunnel.h>
+#include <net/ip6_checksum.h>
+#endif
+
+#define PORT_HASH_BITS 8
+#define PORT_HASH_SIZE (1 << PORT_HASH_BITS)
+
+static int udp_tunnel_net_id;
+
+struct udp_tunnel_net {
+       struct hlist_head sock_list[PORT_HASH_SIZE];
+       spinlock_t  sock_lock;   /* Protecting the sock_list */
+};

 int udp_sock_create(struct net *net, struct udp_port_cfg *cfg,
                    struct socket **sockp)

@@ -82,7 +99,6 @@ int udp_sock_create(struct net *net, struct udp_port_cfg *cfg,
                return -EPFNOSUPPORT;
        }

-
        *sockp = sock;

        return 0;

@@ -97,4 +113,243 @@ error:
 }
 EXPORT_SYMBOL(udp_sock_create);

+
+/* Socket hash table head */
+static inline struct hlist_head *uts_head(struct net *net, const __be16 port)
+{
+       struct udp_tunnel_net *utn = net_generic(net, udp_tunnel_net_id);
+
+       return &utn->sock_list[hash_32(ntohs(port), PORT_HASH_BITS)];
+}
+
+static int handle_offloads(struct sk_buff *skb)
+{
+       if (skb_is_gso(skb)) {
+               int err = skb_unclone(skb, GFP_ATOMIC);
+
+               if (unlikely(err))
+                       return err;
+               skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
+       } else {
+               if (skb->ip_summed != CHECKSUM_PARTIAL)
+                       skb->ip_summed = CHECKSUM_NONE;
+       }
+
+       return 0;
+}
+
+struct udp_tunnel_sock *create_udp_tunnel_socket(struct net *net, size_t size,
+                                                struct udp_tunnel_socket_cfg
+                                                       *cfg)
+{
+       struct udp_tunnel_net *utn = net_generic(net, udp_tunnel_net_id);
+       struct udp_tunnel_sock *uts;
+       struct socket *sock;
+       struct sock *sk;
+       const __be16 port = cfg->port.local_udp_port;
+       const int ipv6 = (cfg->port.family == AF_INET6);
+       int err;
+
+       uts = kzalloc(size, GFP_KERNEL);
+       if (!uts)
+               return ERR_PTR(-ENOMEM);
+
+       err = udp_sock_create(net, &cfg->port, &sock);
+       if (err < 0) {
+               kfree(uts);
+               return NULL;
+       }
+
+       /* Disable multicast loopback */
+       inet_sk(sock->sk)->mc_loop = 0;
+
+       uts->sock = sock;
+       sk = sock->sk;
+       uts->rcv = cfg->rcv;
+       uts->data = cfg->data;
+       rcu_assign_sk_user_data(sock->sk, uts);
+
+       spin_lock(&utn->sock_lock);
+       hlist_add_head_rcu(&uts->hlist, uts_head(net, port));
+       spin_unlock(&utn->sock_lock);
+
+       udp_sk(sk)->encap_type = 1;
+       udp_sk(sk)->encap_rcv = cfg->encap_rcv;
+
+#if IS_ENABLED(CONFIG_IPV6)
+       if (ipv6)
+               ipv6_stub->udpv6_encap_enable();
+       else
+#endif
+               udp_encap_enable();
+
+       return uts;
+}
+EXPORT_SYMBOL_GPL(create_udp_tunnel_socket);
+
+int udp_tunnel_xmit_skb(struct socket *sock, struct rtable *rt,
+                       struct sk_buff *skb, __be32 src, __be32 dst,
+                       __u8 tos, __u8 ttl, __be16 df, __be16 src_port,
+                       __be16 dst_port, bool xnet)
+{
+       struct udphdr *uh;
+
+       __skb_push(skb, sizeof(*uh));
+       skb_reset_transport_header(skb);
+       uh = udp_hdr(skb);
+
+       uh->dest = dst_port;
+       uh->source = src_port;
+       uh->len = htons(skb->len);
+
+       udp_set_csum(sock->sk->sk_no_check_tx, skb, src, dst, skb->len);
+
+       return iptunnel_xmit(sock->sk, rt, skb, src, dst, IPPROTO_UDP,
+                            tos, ttl, df, xnet);
+}
+EXPORT_SYMBOL_GPL(udp_tunnel_xmit_skb);
+
+#if IS_ENABLED(CONFIG_IPV6)
+int udp_tunnel6_xmit_skb(struct socket *sock, struct dst_entry *dst,
+                        struct sk_buff *skb, struct net_device *dev,
+                        struct in6_addr *saddr, struct in6_addr *daddr,
+                        __u8 prio, __u8 ttl, __be16 src_port, __be16 dst_port)
+{
+       struct udphdr *uh;
+       struct ipv6hdr *ip6h;
+       int err;
+
+       __skb_push(skb, sizeof(*uh));
+       skb_reset_transport_header(skb);
+       uh = udp_hdr(skb);
+
+       uh->dest = dst_port;
+       uh->source = src_port;
+
+       uh->len = htons(skb->len);
+       uh->check = 0;
+
+       memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
+       IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED
+                           | IPSKB_REROUTED);
+       skb_dst_set(skb, dst);
+
+       if (!skb_is_gso(skb) && !(dst->dev->features & NETIF_F_IPV6_CSUM)) {
+               __wsum csum = skb_checksum(skb, 0, skb->len, 0);
+
+               skb->ip_summed = CHECKSUM_UNNECESSARY;
+               uh->check = csum_ipv6_magic(saddr, daddr, skb->len,
+                               IPPROTO_UDP, csum);
+               if (uh->check == 0)
+                       uh->check = CSUM_MANGLED_0;
+       } else {
+               skb->ip_summed = CHECKSUM_PARTIAL;
+               skb->csum_start = skb_transport_header(skb) - skb->head;
+               skb->csum_offset = offsetof(struct udphdr, check);
+               uh->check = ~csum_ipv6_magic(saddr, daddr,
+                               skb->len, IPPROTO_UDP, 0);
+       }
+
+       __skb_push(skb, sizeof(*ip6h));
+       skb_reset_network_header(skb);
+       ip6h              = ipv6_hdr(skb);
+       ip6h->version     = 6;
+       ip6h->priority    = prio;
+       ip6h->flow_lbl[0] = 0;
+       ip6h->flow_lbl[1] = 0;
+       ip6h->flow_lbl[2] = 0;
+       ip6h->payload_len = htons(skb->len);
+       ip6h->nexthdr     = IPPROTO_UDP;
+       ip6h->hop_limit   = ttl;
+       ip6h->daddr       = *daddr;
+       ip6h->saddr       = *saddr;
+
+       err = handle_offloads(skb);
+       if (err)
+               return err;
+
+       ip6tunnel_xmit(skb, dev);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(udp_tunnel6_xmit_skb);
+#endif
+
+struct udp_tunnel_sock *udp_tunnel_find_sock(struct net *net, __be16 port)
+{
+       struct udp_tunnel_sock *uts;
+
+       hlist_for_each_entry_rcu(uts, uts_head(net, port), hlist) {
+               if (inet_sk(uts->sock->sk)->inet_sport == port)
+                       return uts;
+       }
+
+       return NULL;
+}
+EXPORT_SYMBOL_GPL(udp_tunnel_find_sock);
+
+void udp_tunnel_sock_release(struct udp_tunnel_sock *uts)
+{
+       struct sock *sk = uts->sock->sk;
+       struct net *net = sock_net(sk);
+       struct udp_tunnel_net *utn = net_generic(net, udp_tunnel_net_id);
+
+       spin_lock(&utn->sock_lock);
+       hlist_del_rcu(&uts->hlist);
+       rcu_assign_sk_user_data(uts->sock->sk, NULL);
+       spin_unlock(&utn->sock_lock);
+}
+EXPORT_SYMBOL_GPL(udp_tunnel_sock_release);
+
+/* Calls the ndo_add_tunnel_port of the caller in order to
+ * supply the listening VXLAN udp ports. Callers are expected
+ * to implement the ndo_add_tunnle_port.
+ */
+void udp_tunnel_get_rx_port(struct net_device *dev)
+{
+       struct udp_tunnel_sock *uts;
+       struct net *net = dev_net(dev);
+       struct udp_tunnel_net *utn = net_generic(net, udp_tunnel_net_id);
+       sa_family_t sa_family;
+       __be16 port;
+       unsigned int i;
+
+       spin_lock(&utn->sock_lock);
+       for (i = 0; i < PORT_HASH_SIZE; ++i) {
+               hlist_for_each_entry_rcu(uts, &utn->sock_list[i], hlist) {
+                       port = inet_sk(uts->sock->sk)->inet_sport;
+                       sa_family = uts->sock->sk->sk_family;
+                       dev->netdev_ops->ndo_add_udp_tunnel_port(dev,
+                                       sa_family, port, uts->tunnel_type);
+               }
+       }
+       spin_unlock(&utn->sock_lock);
+}
+EXPORT_SYMBOL_GPL(udp_tunnel_get_rx_port);
+
+static int __net_init udp_tunnel_init_net(struct net *net)
+{
+       struct udp_tunnel_net *utn = net_generic(net, udp_tunnel_net_id);
+       unsigned int h;
+
+       spin_lock_init(&utn->sock_lock);
+
+       for (h = 0; h < PORT_HASH_SIZE; h++)
+               INIT_HLIST_HEAD(&utn->sock_list[h]);
+
+       return 0;
+}
+
+static struct pernet_operations udp_tunnel_net_ops = {
+       .init = udp_tunnel_init_net,
+       .exit = NULL,
+       .id = &udp_tunnel_net_id,
+       .size = sizeof(struct udp_tunnel_net),
+};
+
+static int __init udp_tunnel_init(void)
+{
+       return register_pernet_subsys(&udp_tunnel_net_ops);
+}
+late_initcall(udp_tunnel_init);
+
 MODULE_LICENSE("GPL");
--

1.7.9.5

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