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udp-tunnel: Add a few more UDP tunnel APIs
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Added a few more UDP tunnel APIs that can be shared by UDP based
tunnel protocol implementation. The main ones are highlighted below.

setup_udp_tunnel_sock() configures UDP listener socket for
receiving UDP encapsulated packets.

udp_tunnel_xmit_skb() and upd_tunnel6_xmit_skb() transmit skb
using UDP encapsulation.

udp_tunnel_sock_release() closes the UDP tunnel listener socket.

Signed-off-by: Andy Zhou <azhou@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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azhou-nicira authored and davem330 committed Sep 19, 2014
1 parent fd38441 commit 6a93cc9
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Showing 3 changed files with 151 additions and 1 deletion.
57 changes: 57 additions & 0 deletions include/net/udp_tunnel.h
Original file line number Diff line number Diff line change
@@ -1,6 +1,14 @@
#ifndef __NET_UDP_TUNNEL_H
#define __NET_UDP_TUNNEL_H

#include <net/ip_tunnels.h>
#include <net/udp.h>

#if IS_ENABLED(CONFIG_IPV6)
#include <net/ipv6.h>
#include <net/addrconf.h>
#endif

struct udp_port_cfg {
u8 family;

Expand Down Expand Up @@ -53,4 +61,53 @@ static inline int udp_sock_create(struct net *net,
return -EPFNOSUPPORT;
}

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_sock_cfg {
void *sk_user_data; /* user data used by encap_rcv call back */
/* 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;
};

/* Setup the given (UDP) sock to receive UDP encapsulated packets */
void setup_udp_tunnel_sock(struct net *net, struct socket *sock,
struct udp_tunnel_sock_cfg *sock_cfg);

/* Transmit the skb using UDP encapsulation. */
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 socket *sock);

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);
}

static inline void udp_tunnel_encap_enable(struct socket *sock)
{
#if IS_ENABLED(CONFIG_IPV6)
if (sock->sk->sk_family == PF_INET6)
ipv6_stub->udpv6_encap_enable();
else
#endif
udp_encap_enable();
}

#endif
53 changes: 52 additions & 1 deletion net/ipv4/udp_tunnel.c
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@
int udp_sock_create4(struct net *net, struct udp_port_cfg *cfg,
struct socket **sockp)
{
int err = -EINVAL;
int err;
struct socket *sock = NULL;
struct sockaddr_in udp_addr;

Expand Down Expand Up @@ -54,4 +54,55 @@ int udp_sock_create4(struct net *net, struct udp_port_cfg *cfg,
}
EXPORT_SYMBOL(udp_sock_create4);

void setup_udp_tunnel_sock(struct net *net, struct socket *sock,
struct udp_tunnel_sock_cfg *cfg)
{
struct sock *sk = sock->sk;

/* Disable multicast loopback */
inet_sk(sk)->mc_loop = 0;

/* Enable CHECKSUM_UNNECESSARY to CHECKSUM_COMPLETE conversion */
udp_set_convert_csum(sk, true);

rcu_assign_sk_user_data(sk, cfg->sk_user_data);

udp_sk(sk)->encap_type = cfg->encap_type;
udp_sk(sk)->encap_rcv = cfg->encap_rcv;
udp_sk(sk)->encap_destroy = cfg->encap_destroy;

udp_tunnel_encap_enable(sock);
}
EXPORT_SYMBOL_GPL(setup_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);

void udp_tunnel_sock_release(struct socket *sock)
{
rcu_assign_sk_user_data(sock->sk, NULL);
kernel_sock_shutdown(sock, SHUT_RDWR);
sk_release_kernel(sock->sk);
}
EXPORT_SYMBOL_GPL(udp_tunnel_sock_release);

MODULE_LICENSE("GPL");
42 changes: 42 additions & 0 deletions net/ipv6/ip6_udp_tunnel.c
Original file line number Diff line number Diff line change
Expand Up @@ -61,3 +61,45 @@ int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg,
return err;
}
EXPORT_SYMBOL_GPL(udp_sock_create6);

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;
struct sock *sk = sock->sk;

__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);

udp6_set_csum(udp_get_no_check6_tx(sk), skb, &inet6_sk(sk)->saddr,
&sk->sk_v6_daddr, skb->len);

__skb_push(skb, sizeof(*ip6h));
skb_reset_network_header(skb);
ip6h = ipv6_hdr(skb);
ip6_flow_hdr(ip6h, prio, htonl(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);

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