369 lines
7.3 KiB
C
369 lines
7.3 KiB
C
#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/socket.h>
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#include <linux/skbuff.h>
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#include <linux/ip.h>
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#include <linux/udp.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <net/genetlink.h>
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#include <net/ip.h>
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#include <net/protocol.h>
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#include <net/udp.h>
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#include <net/udp_tunnel.h>
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#include <net/xfrm.h>
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#include <uapi/linux/fou.h>
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#include <uapi/linux/genetlink.h>
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static DEFINE_SPINLOCK(fou_lock);
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static LIST_HEAD(fou_list);
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struct fou {
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struct socket *sock;
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u8 protocol;
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u16 port;
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struct udp_offload udp_offloads;
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struct list_head list;
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};
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struct fou_cfg {
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u8 protocol;
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struct udp_port_cfg udp_config;
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};
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static inline struct fou *fou_from_sock(struct sock *sk)
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{
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return sk->sk_user_data;
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}
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static int fou_udp_encap_recv_deliver(struct sk_buff *skb,
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u8 protocol, size_t len)
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{
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struct iphdr *iph = ip_hdr(skb);
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/* Remove 'len' bytes from the packet (UDP header and
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* FOU header if present), modify the protocol to the one
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* we found, and then call rcv_encap.
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*/
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iph->tot_len = htons(ntohs(iph->tot_len) - len);
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__skb_pull(skb, len);
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skb_postpull_rcsum(skb, udp_hdr(skb), len);
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skb_reset_transport_header(skb);
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return -protocol;
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}
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static int fou_udp_recv(struct sock *sk, struct sk_buff *skb)
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{
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struct fou *fou = fou_from_sock(sk);
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if (!fou)
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return 1;
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return fou_udp_encap_recv_deliver(skb, fou->protocol,
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sizeof(struct udphdr));
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}
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static struct sk_buff **fou_gro_receive(struct sk_buff **head,
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struct sk_buff *skb,
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const struct net_offload **offloads)
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{
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const struct net_offload *ops;
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struct sk_buff **pp = NULL;
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u8 proto = NAPI_GRO_CB(skb)->proto;
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rcu_read_lock();
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ops = rcu_dereference(offloads[proto]);
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if (!ops || !ops->callbacks.gro_receive)
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goto out_unlock;
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pp = ops->callbacks.gro_receive(head, skb);
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out_unlock:
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rcu_read_unlock();
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return pp;
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}
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static int fou_gro_complete(struct sk_buff *skb, int nhoff,
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const struct net_offload **offloads)
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{
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const struct net_offload *ops;
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u8 proto = NAPI_GRO_CB(skb)->proto;
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int err = -ENOSYS;
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rcu_read_lock();
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ops = rcu_dereference(offloads[proto]);
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if (WARN_ON(!ops || !ops->callbacks.gro_complete))
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goto out_unlock;
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err = ops->callbacks.gro_complete(skb, nhoff);
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out_unlock:
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rcu_read_unlock();
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return err;
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}
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static struct sk_buff **fou4_gro_receive(struct sk_buff **head,
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struct sk_buff *skb)
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{
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return fou_gro_receive(head, skb, inet_offloads);
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}
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static int fou4_gro_complete(struct sk_buff *skb, int nhoff)
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{
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return fou_gro_complete(skb, nhoff, inet_offloads);
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}
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static struct sk_buff **fou6_gro_receive(struct sk_buff **head,
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struct sk_buff *skb)
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{
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return fou_gro_receive(head, skb, inet6_offloads);
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}
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static int fou6_gro_complete(struct sk_buff *skb, int nhoff)
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{
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return fou_gro_complete(skb, nhoff, inet6_offloads);
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}
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static int fou_add_to_port_list(struct fou *fou)
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{
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struct fou *fout;
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spin_lock(&fou_lock);
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list_for_each_entry(fout, &fou_list, list) {
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if (fou->port == fout->port) {
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spin_unlock(&fou_lock);
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return -EALREADY;
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}
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}
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list_add(&fou->list, &fou_list);
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spin_unlock(&fou_lock);
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return 0;
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}
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static void fou_release(struct fou *fou)
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{
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struct socket *sock = fou->sock;
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struct sock *sk = sock->sk;
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udp_del_offload(&fou->udp_offloads);
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list_del(&fou->list);
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/* Remove hooks into tunnel socket */
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sk->sk_user_data = NULL;
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sock_release(sock);
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kfree(fou);
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}
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static int fou_create(struct net *net, struct fou_cfg *cfg,
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struct socket **sockp)
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{
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struct fou *fou = NULL;
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int err;
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struct socket *sock = NULL;
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struct sock *sk;
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/* Open UDP socket */
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err = udp_sock_create(net, &cfg->udp_config, &sock);
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if (err < 0)
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goto error;
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/* Allocate FOU port structure */
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fou = kzalloc(sizeof(*fou), GFP_KERNEL);
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if (!fou) {
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err = -ENOMEM;
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goto error;
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}
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sk = sock->sk;
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/* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
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fou->protocol = cfg->protocol;
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fou->port = cfg->udp_config.local_udp_port;
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udp_sk(sk)->encap_rcv = fou_udp_recv;
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udp_sk(sk)->encap_type = 1;
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udp_encap_enable();
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sk->sk_user_data = fou;
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fou->sock = sock;
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udp_set_convert_csum(sk, true);
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sk->sk_allocation = GFP_ATOMIC;
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switch (cfg->udp_config.family) {
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case AF_INET:
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fou->udp_offloads.callbacks.gro_receive = fou4_gro_receive;
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fou->udp_offloads.callbacks.gro_complete = fou4_gro_complete;
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break;
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case AF_INET6:
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fou->udp_offloads.callbacks.gro_receive = fou6_gro_receive;
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fou->udp_offloads.callbacks.gro_complete = fou6_gro_complete;
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break;
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default:
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err = -EPFNOSUPPORT;
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goto error;
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}
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fou->udp_offloads.port = cfg->udp_config.local_udp_port;
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fou->udp_offloads.ipproto = cfg->protocol;
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if (cfg->udp_config.family == AF_INET) {
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err = udp_add_offload(&fou->udp_offloads);
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if (err)
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goto error;
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}
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err = fou_add_to_port_list(fou);
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if (err)
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goto error;
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if (sockp)
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*sockp = sock;
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return 0;
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error:
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kfree(fou);
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if (sock)
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sock_release(sock);
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return err;
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}
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static int fou_destroy(struct net *net, struct fou_cfg *cfg)
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{
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struct fou *fou;
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u16 port = cfg->udp_config.local_udp_port;
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int err = -EINVAL;
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spin_lock(&fou_lock);
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list_for_each_entry(fou, &fou_list, list) {
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if (fou->port == port) {
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udp_del_offload(&fou->udp_offloads);
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fou_release(fou);
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err = 0;
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break;
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}
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}
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spin_unlock(&fou_lock);
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return err;
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}
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static struct genl_family fou_nl_family = {
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.id = GENL_ID_GENERATE,
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.hdrsize = 0,
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.name = FOU_GENL_NAME,
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.version = FOU_GENL_VERSION,
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.maxattr = FOU_ATTR_MAX,
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.netnsok = true,
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};
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static struct nla_policy fou_nl_policy[FOU_ATTR_MAX + 1] = {
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[FOU_ATTR_PORT] = { .type = NLA_U16, },
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[FOU_ATTR_AF] = { .type = NLA_U8, },
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[FOU_ATTR_IPPROTO] = { .type = NLA_U8, },
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};
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static int parse_nl_config(struct genl_info *info,
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struct fou_cfg *cfg)
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{
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memset(cfg, 0, sizeof(*cfg));
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cfg->udp_config.family = AF_INET;
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if (info->attrs[FOU_ATTR_AF]) {
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u8 family = nla_get_u8(info->attrs[FOU_ATTR_AF]);
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if (family != AF_INET && family != AF_INET6)
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return -EINVAL;
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cfg->udp_config.family = family;
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}
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if (info->attrs[FOU_ATTR_PORT]) {
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u16 port = nla_get_u16(info->attrs[FOU_ATTR_PORT]);
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cfg->udp_config.local_udp_port = port;
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}
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if (info->attrs[FOU_ATTR_IPPROTO])
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cfg->protocol = nla_get_u8(info->attrs[FOU_ATTR_IPPROTO]);
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return 0;
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}
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static int fou_nl_cmd_add_port(struct sk_buff *skb, struct genl_info *info)
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{
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struct fou_cfg cfg;
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int err;
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err = parse_nl_config(info, &cfg);
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if (err)
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return err;
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return fou_create(&init_net, &cfg, NULL);
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}
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static int fou_nl_cmd_rm_port(struct sk_buff *skb, struct genl_info *info)
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{
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struct fou_cfg cfg;
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parse_nl_config(info, &cfg);
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return fou_destroy(&init_net, &cfg);
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}
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static const struct genl_ops fou_nl_ops[] = {
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{
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.cmd = FOU_CMD_ADD,
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.doit = fou_nl_cmd_add_port,
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.policy = fou_nl_policy,
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.flags = GENL_ADMIN_PERM,
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},
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{
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.cmd = FOU_CMD_DEL,
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.doit = fou_nl_cmd_rm_port,
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.policy = fou_nl_policy,
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.flags = GENL_ADMIN_PERM,
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},
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};
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static int __init fou_init(void)
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{
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int ret;
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ret = genl_register_family_with_ops(&fou_nl_family,
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fou_nl_ops);
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return ret;
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}
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static void __exit fou_fini(void)
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{
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struct fou *fou, *next;
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genl_unregister_family(&fou_nl_family);
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/* Close all the FOU sockets */
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spin_lock(&fou_lock);
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list_for_each_entry_safe(fou, next, &fou_list, list)
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fou_release(fou);
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spin_unlock(&fou_lock);
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}
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module_init(fou_init);
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module_exit(fou_fini);
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MODULE_AUTHOR("Tom Herbert <therbert@google.com>");
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MODULE_LICENSE("GPL");
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