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Date: Tue, 26 Aug 2014 21:12:24 -0700
From: Tom Herbert <therbert@...gle.com>
To: Andy Zhou <azhou@...ira.com>
Cc: David Miller <davem@...emloft.net>,
Linux Netdev List <netdev@...r.kernel.org>
Subject: Re: [net-next v3 1/3] udp: Expand UDP tunnel common APIs
On Tue, Aug 26, 2014 at 8:35 PM, Andy Zhou <azhou@...ira.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.
>
This is not needed! If a UDP port is already bound (whether by another
tunnel or not), then bind during tunnel initialization will fail. All
this logic to store tunnel sockets in a separate list seems like
unnecessary complexity. If a driver needs to track multiple ports it
opens, it can do that on its own like VXLAN is already doing.
> Signed-off-by: Andy Zhou <azhou@...ira.com>
> ---
> include/net/udp_tunnel.h | 50 +++++++++++
> net/ipv4/udp_tunnel.c | 216 +++++++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 265 insertions(+), 1 deletion(-)
>
> diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
> index ffd69cb..5ff0746 100644
> --- a/include/net/udp_tunnel.h
> +++ b/include/net/udp_tunnel.h
> @@ -1,6 +1,8 @@
> #ifndef __NET_UDP_TUNNEL_H
> #define __NET_UDP_TUNNEL_H
>
> +#include <net/ip_tunnels.h>
> +
> struct udp_port_cfg {
> u8 family;
>
> @@ -26,7 +28,55 @@ struct udp_port_cfg {
> use_udp6_rx_checksums:1;
> };
>
> +struct udp_tunnel_sock;
> +
> +typedef int (*udp_tunnel_encap_rcv_t)(struct sock *sk, struct sk_buff *skb);
> +typedef void (*udp_tunnel_encap_destroy_t)(struct sock *sk);
> +
> +struct udp_tunnel_socket_cfg {
> + struct udp_port_cfg port;
> +
> + /* Used for setting up udp_sock fields, see udp.h for details */
> + __u8 encap_type;
> + udp_tunnel_encap_rcv_t encap_rcv;
> + udp_tunnel_encap_destroy_t encap_destroy;
> +};
> +
> +struct udp_tunnel_sock {
> + struct hlist_node hlist;
> + 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_sock(struct net *net, size_t size,
> + struct socket *sock,
> + 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);
> +
> +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..3ed66bc 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 +113,202 @@ 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)];
> +}
> +
> +struct udp_tunnel_sock *create_udp_tunnel_sock(struct net *net, size_t size,
> + struct socket *sock,
> + struct udp_tunnel_socket_cfg
> + *cfg)
> +{
> + struct udp_tunnel_net *utn = net_generic(net, udp_tunnel_net_id);
> + struct udp_tunnel_sock *uts;
> + struct sock *sk;
> + const __be16 port = cfg->port.local_udp_port;
> + const int ipv6 = (cfg->port.family == AF_INET6);
> + int err;
> +
> + if (!sock)
> + err = udp_sock_create(net, &cfg->port, &sock);
> + else
> + err = (sock->sk->sk_protocol == IPPROTO_UDP) ?
> + 0 : -EPROTONOSUPPORT;
> +
> + if (err)
> + return NULL;
> +
> + uts = kzalloc(size, GFP_KERNEL);
> + if (!uts)
> + return ERR_PTR(-ENOMEM);
> +
> + sk = sock->sk;
> +
> + /* Disable multicast loopback */
> + inet_sk(sk)->mc_loop = 0;
> +
> + rcu_assign_sk_user_data(sk, uts);
> +
> + udp_sk(sk)->encap_type = cfg->encap_type;
> + udp_sk(sk)->encap_rcv = cfg->encap_rcv;
> + udp_sk(sk)->encap_destroy = cfg->encap_destroy;
> +
> + uts->sock = sock;
> +
> + spin_lock(&utn->sock_lock);
> + hlist_add_head_rcu(&uts->hlist, uts_head(net, port));
> + spin_unlock(&utn->sock_lock);
> +
> +#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_sock);
> +
> +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;
> +
> + __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;
> +
> + 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);
> + kernel_sock_shutdown(uts->sock, SHUT_RDWR);
> + sk_release_kernel(sk);
> + spin_unlock(&utn->sock_lock);
> +}
> +EXPORT_SYMBOL_GPL(udp_tunnel_sock_release);
> +
> +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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