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

[Andy Zhou <azhou@nicira.com>]

The general layering I see is  tunnel_user (i.e. OVS) -> tuunel_driver
(i.e. vxlan) -> udp_tunnel.

The two receive functions are from two separate layers above
udp_tunnel. I can restructure the APIs to make it
cleaner.

On Wed, Jul 23, 2014 at 12:57 PM, Tom Herbert <therbert@google.com> wrote:
> On Tue, Jul 22, 2014 at 3:19 AM, Andy Zhou <azhou@nicira.com> wrote:
>> 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 <azhou@nicira.com>
>> ---
>>  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;
>
> Why do you need two receive functions or udp_tunnel_rcv_t?
>
>> +       void *data;
>
> Similarly, why is this needed when we already have sk_user_data?
>
>> +};
>> +
>> +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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