- 根目录:
- net
- ipv4
- fou.c
#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>
static DEFINE_SPINLOCK(fou_lock);
static LIST_HEAD(fou_list);
struct fou {
struct socket *sock;
u8 protocol;
u16 port;
struct udp_offload udp_offloads;
struct list_head list;
};
struct fou_cfg {
u16 type;
u8 protocol;
struct udp_port_cfg udp_config;
};
static inline struct fou *fou_from_sock(struct sock *sk)
{
return sk->sk_user_data;
}
static int fou_udp_encap_recv_deliver(struct sk_buff *skb,
u8 protocol, size_t len)
{
struct iphdr *iph = ip_hdr(skb);
/* Remove 'len' bytes from the packet (UDP header and
* FOU header if present), modify the protocol to the one
* we found, and then call rcv_encap.
*/
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 -protocol;
}
static int fou_udp_recv(struct sock *sk, struct sk_buff *skb)
{
struct fou *fou = fou_from_sock(sk);
if (!fou)
return 1;
return fou_udp_encap_recv_deliver(skb, fou->protocol,
sizeof(struct udphdr));
}
static int gue_udp_recv(struct sock *sk, struct sk_buff *skb)
{
struct fou *fou = fou_from_sock(sk);
size_t len;
struct guehdr *guehdr;
struct udphdr *uh;
if (!fou)
return 1;
len = sizeof(struct udphdr) + sizeof(struct guehdr);
if (!pskb_may_pull(skb, len))
goto drop;
uh = udp_hdr(skb);
guehdr = (struct guehdr *)&uh[1];
len += guehdr->hlen << 2;
if (!pskb_may_pull(skb, len))
goto drop;
uh = udp_hdr(skb);
guehdr = (struct guehdr *)&uh[1];
if (guehdr->version != 0)
goto drop;
if (guehdr->flags) {
/* No support yet */
goto drop;
}
return fou_udp_encap_recv_deliver(skb, guehdr->next_hdr, len);
drop:
kfree_skb(skb);
return 0;
}
static struct sk_buff **fou_gro_receive(struct sk_buff **head,
struct sk_buff *skb)
{
const struct net_offload *ops;
struct sk_buff **pp = NULL;
u8 proto = NAPI_GRO_CB(skb)->proto;
const struct net_offload **offloads;
rcu_read_lock();
offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
ops = rcu_dereference(offloads[proto]);
if (!ops || !ops->callbacks.gro_receive)
goto out_unlock;
pp = ops->callbacks.gro_receive(head, skb);
out_unlock:
rcu_read_unlock();
return pp;
}
static int fou_gro_complete(struct sk_buff *skb, int nhoff)
{
const struct net_offload *ops;
u8 proto = NAPI_GRO_CB(skb)->proto;
int err = -ENOSYS;
const struct net_offload **offloads;
udp_tunnel_gro_complete(skb, nhoff);
rcu_read_lock();
offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
ops = rcu_dereference(offloads[proto]);
if (WARN_ON(!ops || !ops->callbacks.gro_complete))
goto out_unlock;
err = ops->callbacks.gro_complete(skb, nhoff);
out_unlock:
rcu_read_unlock();
return err;
}
static struct sk_buff **gue_gro_receive(struct sk_buff **head,
struct sk_buff *skb)
{
const struct net_offload **offloads;
const struct net_offload *ops;
struct sk_buff **pp = NULL;
struct sk_buff *p;
u8 proto;
struct guehdr *guehdr;
unsigned int hlen, guehlen;
unsigned int off;
int flush = 1;
off = skb_gro_offset(skb);
hlen = off + sizeof(*guehdr);
guehdr = skb_gro_header_fast(skb, off);
if (skb_gro_header_hard(skb, hlen)) {
guehdr = skb_gro_header_slow(skb, hlen, off);
if (unlikely(!guehdr))
goto out;
}
proto = guehdr->next_hdr;
rcu_read_lock();
offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
ops = rcu_dereference(offloads[proto]);
if (WARN_ON(!ops || !ops->callbacks.gro_receive))
goto out_unlock;
guehlen = sizeof(*guehdr) + (guehdr->hlen << 2);
hlen = off + guehlen;
if (skb_gro_header_hard(skb, hlen)) {
guehdr = skb_gro_header_slow(skb, hlen, off);
if (unlikely(!guehdr))
goto out_unlock;
}
flush = 0;
for (p = *head; p; p = p->next) {
const struct guehdr *guehdr2;
if (!NAPI_GRO_CB(p)->same_flow)
continue;
guehdr2 = (struct guehdr *)(p->data + off);
/* Compare base GUE header to be equal (covers
* hlen, version, next_hdr, and flags.
*/
if (guehdr->word != guehdr2->word) {
NAPI_GRO_CB(p)->same_flow = 0;
continue;
}
/* Compare optional fields are the same. */
if (guehdr->hlen && memcmp(&guehdr[1], &guehdr2[1],
guehdr->hlen << 2)) {
NAPI_GRO_CB(p)->same_flow = 0;
continue;
}
}
skb_gro_pull(skb, guehlen);
/* Adjusted NAPI_GRO_CB(skb)->csum after skb_gro_pull()*/
skb_gro_postpull_rcsum(skb, guehdr, guehlen);
pp = ops->callbacks.gro_receive(head, skb);
out_unlock:
rcu_read_unlock();
out:
NAPI_GRO_CB(skb)->flush |= flush;
return pp;
}
static int gue_gro_complete(struct sk_buff *skb, int nhoff)
{
const struct net_offload **offloads;
struct guehdr *guehdr = (struct guehdr *)(skb->data + nhoff);
const struct net_offload *ops;
unsigned int guehlen;
u8 proto;
int err = -ENOENT;
proto = guehdr->next_hdr;
guehlen = sizeof(*guehdr) + (guehdr->hlen << 2);
rcu_read_lock();
offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
ops = rcu_dereference(offloads[proto]);
if (WARN_ON(!ops || !ops->callbacks.gro_complete))
goto out_unlock;
err = ops->callbacks.gro_complete(skb, nhoff + guehlen);
out_unlock:
rcu_read_unlock();
return err;
}
static int fou_add_to_port_list(struct fou *fou)
{
struct fou *fout;
spin_lock(&fou_lock);
list_for_each_entry(fout, &fou_list, list) {
if (fou->port == fout->port) {
spin_unlock(&fou_lock);
return -EALREADY;
}
}
list_add(&fou->list, &fou_list);
spin_unlock(&fou_lock);
return 0;
}
static void fou_release(struct fou *fou)
{
struct socket *sock = fou->sock;
struct sock *sk = sock->sk;
udp_del_offload(&fou->udp_offloads);
list_del(&fou->list);
/* Remove hooks into tunnel socket */
sk->sk_user_data = NULL;
sock_release(sock);
kfree(fou);
}
static int fou_encap_init(struct sock *sk, struct fou *fou, struct fou_cfg *cfg)
{
udp_sk(sk)->encap_rcv = fou_udp_recv;
fou->protocol = cfg->protocol;
fou->udp_offloads.callbacks.gro_receive = fou_gro_receive;
fou->udp_offloads.callbacks.gro_complete = fou_gro_complete;
fou->udp_offloads.port = cfg->udp_config.local_udp_port;
fou->udp_offloads.ipproto = cfg->protocol;
return 0;
}
static int gue_encap_init(struct sock *sk, struct fou *fou, struct fou_cfg *cfg)
{
udp_sk(sk)->encap_rcv = gue_udp_recv;
fou->udp_offloads.callbacks.gro_receive = gue_gro_receive;
fou->udp_offloads.callbacks.gro_complete = gue_gro_complete;
fou->udp_offloads.port = cfg->udp_config.local_udp_port;
return 0;
}
static int fou_create(struct net *net, struct fou_cfg *cfg,
struct socket **sockp)
{
struct fou *fou = NULL;
int err;
struct socket *sock = NULL;
struct sock *sk;
/* Open UDP socket */
err = udp_sock_create(net, &cfg->udp_config, &sock);
if (err < 0)
goto error;
/* Allocate FOU port structure */
fou = kzalloc(sizeof(*fou), GFP_KERNEL);
if (!fou) {
err = -ENOMEM;
goto error;
}
sk = sock->sk;
fou->port = cfg->udp_config.local_udp_port;
/* Initial for fou type */
switch (cfg->type) {
case FOU_ENCAP_DIRECT:
err = fou_encap_init(sk, fou, cfg);
if (err)
goto error;
break;
case FOU_ENCAP_GUE:
err = gue_encap_init(sk, fou, cfg);
if (err)
goto error;
break;
default:
err = -EINVAL;
goto error;
}
udp_sk(sk)->encap_type = 1;
udp_encap_enable();
sk->sk_user_data = fou;
fou->sock = sock;
udp_set_convert_csum(sk, true);
sk->sk_allocation = GFP_ATOMIC;
if (cfg->udp_config.family == AF_INET) {
err = udp_add_offload(&fou->udp_offloads);
if (err)
goto error;
}
err = fou_add_to_port_list(fou);
if (err)
goto error;
if (sockp)
*sockp = sock;
return 0;
error:
kfree(fou);
if (sock)
sock_release(sock);
return err;
}
static int fou_destroy(struct net *net, struct fou_cfg *cfg)
{
struct fou *fou;
u16 port = cfg->udp_config.local_udp_port;
int err = -EINVAL;
spin_lock(&fou_lock);
list_for_each_entry(fou, &fou_list, list) {
if (fou->port == port) {
udp_del_offload(&fou->udp_offloads);
fou_release(fou);
err = 0;
break;
}
}
spin_unlock(&fou_lock);
return err;
}
static struct genl_family fou_nl_family = {
.id = GENL_ID_GENERATE,
.hdrsize = 0,
.name = FOU_GENL_NAME,
.version = FOU_GENL_VERSION,
.maxattr = FOU_ATTR_MAX,
.netnsok = true,
};
static struct nla_policy fou_nl_policy[FOU_ATTR_MAX + 1] = {
[FOU_ATTR_PORT] = { .type = NLA_U16, },
[FOU_ATTR_AF] = { .type = NLA_U8, },
[FOU_ATTR_IPPROTO] = { .type = NLA_U8, },
[FOU_ATTR_TYPE] = { .type = NLA_U8, },
};
static int parse_nl_config(struct genl_info *info,
struct fou_cfg *cfg)
{
memset(cfg, 0, sizeof(*cfg));
cfg->udp_config.family = AF_INET;
if (info->attrs[FOU_ATTR_AF]) {
u8 family = nla_get_u8(info->attrs[FOU_ATTR_AF]);
if (family != AF_INET && family != AF_INET6)
return -EINVAL;
cfg->udp_config.family = family;
}
if (info->attrs[FOU_ATTR_PORT]) {
u16 port = nla_get_u16(info->attrs[FOU_ATTR_PORT]);
cfg->udp_config.local_udp_port = port;
}
if (info->attrs[FOU_ATTR_IPPROTO])
cfg->protocol = nla_get_u8(info->attrs[FOU_ATTR_IPPROTO]);
if (info->attrs[FOU_ATTR_TYPE])
cfg->type = nla_get_u8(info->attrs[FOU_ATTR_TYPE]);
return 0;
}
static int fou_nl_cmd_add_port(struct sk_buff *skb, struct genl_info *info)
{
struct fou_cfg cfg;
int err;
err = parse_nl_config(info, &cfg);
if (err)
return err;
return fou_create(&init_net, &cfg, NULL);
}
static int fou_nl_cmd_rm_port(struct sk_buff *skb, struct genl_info *info)
{
struct fou_cfg cfg;
parse_nl_config(info, &cfg);
return fou_destroy(&init_net, &cfg);
}
static const struct genl_ops fou_nl_ops[] = {
{
.cmd = FOU_CMD_ADD,
.doit = fou_nl_cmd_add_port,
.policy = fou_nl_policy,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = FOU_CMD_DEL,
.doit = fou_nl_cmd_rm_port,
.policy = fou_nl_policy,
.flags = GENL_ADMIN_PERM,
},
};
static int __init fou_init(void)
{
int ret;
ret = genl_register_family_with_ops(&fou_nl_family,
fou_nl_ops);
return ret;
}
static void __exit fou_fini(void)
{
struct fou *fou, *next;
genl_unregister_family(&fou_nl_family);
/* Close all the FOU sockets */
spin_lock(&fou_lock);
list_for_each_entry_safe(fou, next, &fou_list, list)
fou_release(fou);
spin_unlock(&fou_lock);
}
module_init(fou_init);
module_exit(fou_fini);
MODULE_AUTHOR("Tom Herbert <therbert@google.com>");
MODULE_LICENSE("GPL");