#include <linux/module.h>
#include <linux/errno.h>
#include <linux/socket.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/udp.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <net/genetlink.h>
#include <net/gue.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/udp.h>
#include <net/udp_tunnel.h>
#include <net/xfrm.h>
#include <uapi/linux/fou.h>
#include <uapi/linux/genetlink.h>
struct fou {
struct socket *sock;
u8 protocol;
u8 flags;
__be16 port;
u16 type;
struct list_head list;
struct rcu_head rcu;
};
#define FOU_F_REMCSUM_NOPARTIAL BIT(0)
struct fou_cfg {
u16 type;
u8 protocol;
u8 flags;
struct udp_port_cfg udp_config;
};
static unsigned int fou_net_id;
struct fou_net {
struct list_head fou_list;
struct mutex fou_lock;
};
static inline struct fou *fou_from_sock(struct sock *sk)
{
return sk->sk_user_data;
}
static int fou_recv_pull(struct sk_buff *skb, size_t len)
{
struct iphdr *iph = ip_hdr(skb);
/* Remove 'len' bytes from the packet (UDP header and
* FOU header if present).
*/
iph->tot_len = htons(ntohs(iph->tot_len) - len);
__skb_pull(skb, len);
skb_postpull_rcsum(skb, udp_hdr(skb), len);
skb_reset_transport_header(skb);
return iptunnel_pull_offloads(skb);
}
static int fou_udp_recv(struct sock *sk, struct sk_buff *skb)
{
struct fou *fou = fou_from_sock(sk);
if (!fou)
return 1;
if (fou_recv_pull(skb, sizeof(struct udphdr)))
goto drop;
return -fou->protocol;
drop:
kfree_skb(skb);
return 0;
}
static struct guehdr *gue_remcsum(struct sk_buff *skb, struct guehdr *guehdr,
void *data, size_t hdrlen, u8 ipproto,
bool nopartial)
{
__be16 *pd = data;
size_t start = ntohs(pd[0]);
size_t offset = ntohs(pd[1]);
size_t plen = sizeof(struct udphdr) + hdrlen +
max_t(size_t, offset + sizeof(u16), start);
if (skb->remcsum_offload)
return guehdr;
if (!pskb_may_pull(skb, plen))
return NULL;
guehdr = (struct guehdr *)&udp_hdr(skb)[1];
skb_remcsum_process(skb, (void *)guehdr + hdrlen,
start, offset, nopartial);
return guehdr;
}
static int gue_control_message(struct sk_buff *skb, struct guehdr *guehdr)
{
/* No support yet */
kfree_skb(skb);
return 0;
}
static int gue_udp_recv(struct sock *sk, struct sk_buff *skb)
{
struct fou *fou = fou_from_sock(sk);
size_t len, optlen, hdrlen;
struct guehdr *guehdr;
void *data;
u16 doffset = 0;
if (!fou)
return 1;
len = sizeof(struct udphdr) + sizeof(struct guehdr);
if (!pskb_may_pull(skb, len))
goto drop;
guehdr = (struct guehdr *)&udp_hdr(skb)[1];
optlen = guehdr->hlen << 2;
len += optlen;
if (!pskb_may_pull(skb, len))
goto drop;
/* guehdr may change after pull */
guehdr = (struct guehdr *)&udp_hdr(skb)[1];
hdrlen = sizeof(struct guehdr) + optlen;
if (guehdr->version != 0 || validate_gue_flags(guehdr, optlen))
goto drop;
hdrlen = sizeof(struct guehdr) + optlen;<