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|
#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 void 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);
}
static int fou_udp_recv(struct sock *sk, struct sk_buff *skb)
{
struct fou *fou = fou_from_sock(sk);
if (!fou)
return 1;
fou_recv_pull(skb, sizeof(struct udphdr));
return -fou->protocol;
}
static struct guehdr *gue_remcsum(struct sk_buff *skb, struct guehdr *guehdr,
void *data, size_t hdrlen, u8 ipproto)
{
__be16 *pd = data;
size_t start = ntohs(pd[0]);
size_t offset = ntohs(pd[1]);
size_t plen = hdrlen + max_t(size_t, offset + sizeof(u16), start);
__wsum delta;
if (skb->remcsum_offload) {
/* Already processed in GRO path */
skb->remcsum_offload = 0;
return guehdr;
}
if (!pskb_may_pull(skb, plen))
return NULL;
guehdr = (struct guehdr *)&udp_hdr(skb)[1];
if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE))
__skb_checksum_complete(skb);
delta = remcsum_adjust((void *)guehdr + hdrlen,
skb->csum, start, offset);
/* Adjust skb->csum since we changed the packet */
skb->csum = csum_add(skb->csum, delta);
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;
ip_hdr(skb)->tot_len = htons(ntohs(ip_hdr(skb)->tot_len) - len);
/* Pull csum through the guehdr now . This can be used if
* there is a remote checksum offload.
*/
skb_postpull_rcsum(skb, udp_hdr(skb), len);
data = &guehdr[1];
if (guehdr->flags & GUE_FLAG_PRIV) {
__be32 flags = *(__be32 *)(data + doffset);
doffset += GUE_LEN_PRIV;
if (flags & GUE_PFLAG_REMCSUM) {
guehdr = gue_remcsum(skb, guehdr, data + doffset,
hdrlen, guehdr->proto_ctype);
if (!guehdr)
goto drop;
data = &guehdr[1];
doffset += GUE_PLEN_REMCSUM;
}
}
if (unlikely(guehdr->control))
return gue_control_message(skb, guehdr);
__skb_pull(skb, sizeof(struct udphdr) + hdrlen);
skb_reset_transport_header(skb);
return -guehdr->proto_ctype;
drop:
kfree_skb(skb);
return 0;
}
static struct sk_buff **fou_gro_receive(struct sk_buff **head,
struct sk_buff *skb,
struct udp_offload *uoff)
{
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,
struct udp_offload *uoff)
{
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 guehdr *gue_gro_remcsum(struct sk_buff *skb, unsigned int off,
struct guehdr *guehdr, void *data,
size_t hdrlen, u8 ipproto)
{
__be16 *pd = data;
size_t start = ntohs(pd[0]);
size_t offset = ntohs(pd[1]);
size_t plen = hdrlen + max_t(size_t, offset + sizeof(u16), start);
__wsum delta;
if (skb->remcsum_offload)
return guehdr;
if (!NAPI_GRO_CB(skb)->csum_valid)
return NULL;
/* Pull checksum that will be written */
if (skb_gro_header_hard(skb, off + plen)) {
guehdr = skb_gro_header_slow(skb, off + plen, off);
if (!guehdr)
return NULL;
}
delta = remcsum_adjust((void *)guehdr + hdrlen,
NAPI_GRO_CB(skb)->csum, start, offset);
/* Adjust skb->csum since we changed the packet */
skb->csum = csum_add(skb->csum, delta);
NAPI_GRO_CB(skb)->csum = csum_add(NAPI_GRO_CB(skb)->csum, delta);
skb->remcsum_offload = 1;
return guehdr;
}
static struct sk_buff **gue_gro_receive(struct sk_buff **head,
struct sk_buff *skb,
struct udp_offload *uoff)
{
const struct net_offload **offloads;
const struct net_offload *ops;
struct sk_buff **pp = NULL;
struct sk_buff *p;
struct guehdr *guehdr;
size_t len, optlen, hdrlen, off;
void *data;
u16 doffset = 0;
int flush = 1;
off = skb_gro_offset(skb);
len = off + sizeof(*guehdr);
guehdr = skb_gro_header_fast(skb, off);
if (skb_gro_header_hard(skb, len)) {
guehdr = skb_gro_header_slow(skb, len, off);
if (unlikely(!guehdr))
goto out;
}
optlen = guehdr->hlen << 2;
len += optlen;
if (skb_gro_header_hard(skb, len)) {
guehdr = skb_gro_header_slow(skb, len, off);
if (unlikely(!guehdr))
goto out;
}
if (unlikely(guehdr->control) || guehdr->version != 0 ||
validate_gue_flags(guehdr, optlen))
goto out;
hdrlen = sizeof(*guehdr) + optlen;
/* Adjust NAPI_GRO_CB(skb)->csum to account for guehdr,
* this is needed if there is a remote checkcsum offload.
*/
skb_gro_postpull_rcsum(skb, guehdr, hdrlen);
data = &guehdr[1];
if (guehdr->flags & GUE_FLAG_PRIV) {
__be32 flags = *(__be32 *)(data + doffset);
doffset += GUE_LEN_PRIV;
if (flags & GUE_PFLAG_REMCSUM) {
guehdr = gue_gro_remcsum(skb, off, guehdr,
data + doffset, hdrlen,
guehdr->proto_ctype);
if (!guehdr)
goto out;
data = &guehdr[1];
doffset += GUE_PLEN_REMCSUM;
}
}
skb_gro_pull(skb, hdrlen);
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, proto_ctype, 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;
}
}
rcu_read_lock();
offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
ops = rcu_dereference(offloads[guehdr->proto_ctype]);
if (WARN_ON(!ops || !ops->callbacks.gro_receive))
goto out_unlock;
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,
struct udp_offload *uoff)
{
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->proto_ctype;
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;
inet_inc_convert_csum(sk);
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,
},
};
size_t fou_encap_hlen(struct ip_tunnel_encap *e)
{
return sizeof(struct udphdr);
}
EXPORT_SYMBOL(fou_encap_hlen);
size_t gue_encap_hlen(struct ip_tunnel_encap *e)
{
size_t len;
bool need_priv = false;
len = sizeof(struct udphdr) + sizeof(struct guehdr);
if (e->flags & TUNNEL_ENCAP_FLAG_REMCSUM) {
len += GUE_PLEN_REMCSUM;
need_priv = true;
}
len += need_priv ? GUE_LEN_PRIV : 0;
return len;
}
EXPORT_SYMBOL(gue_encap_hlen);
static void fou_build_udp(struct sk_buff *skb, struct ip_tunnel_encap *e,
struct flowi4 *fl4, u8 *protocol, __be16 sport)
{
struct udphdr *uh;
skb_push(skb, sizeof(struct udphdr));
skb_reset_transport_header(skb);
uh = udp_hdr(skb);
uh->dest = e->dport;
uh->source = sport;
uh->len = htons(skb->len);
uh->check = 0;
udp_set_csum(!(e->flags & TUNNEL_ENCAP_FLAG_CSUM), skb,
fl4->saddr, fl4->daddr, skb->len);
*protocol = IPPROTO_UDP;
}
int fou_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
u8 *protocol, struct flowi4 *fl4)
{
bool csum = !!(e->flags & TUNNEL_ENCAP_FLAG_CSUM);
int type = csum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
__be16 sport;
skb = iptunnel_handle_offloads(skb, csum, type);
if (IS_ERR(skb))
return PTR_ERR(skb);
sport = e->sport ? : udp_flow_src_port(dev_net(skb->dev),
skb, 0, 0, false);
fou_build_udp(skb, e, fl4, protocol, sport);
return 0;
}
EXPORT_SYMBOL(fou_build_header);
int gue_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
u8 *protocol, struct flowi4 *fl4)
{
bool csum = !!(e->flags & TUNNEL_ENCAP_FLAG_CSUM);
int type = csum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
struct guehdr *guehdr;
size_t hdrlen, optlen = 0;
__be16 sport;
void *data;
bool need_priv = false;
if ((e->flags & TUNNEL_ENCAP_FLAG_REMCSUM) &&
skb->ip_summed == CHECKSUM_PARTIAL) {
csum = false;
optlen += GUE_PLEN_REMCSUM;
type |= SKB_GSO_TUNNEL_REMCSUM;
need_priv = true;
}
optlen += need_priv ? GUE_LEN_PRIV : 0;
skb = iptunnel_handle_offloads(skb, csum, type);
if (IS_ERR(skb))
return PTR_ERR(skb);
/* Get source port (based on flow hash) before skb_push */
sport = e->sport ? : udp_flow_src_port(dev_net(skb->dev),
skb, 0, 0, false);
hdrlen = sizeof(struct guehdr) + optlen;
skb_push(skb, hdrlen);
guehdr = (struct guehdr *)skb->data;
guehdr->control = 0;
guehdr->version = 0;
guehdr->hlen = optlen >> 2;
guehdr->flags = 0;
guehdr->proto_ctype = *protocol;
data = &guehdr[1];
if (need_priv) {
__be32 *flags = data;
guehdr->flags |= GUE_FLAG_PRIV;
*flags = 0;
data += GUE_LEN_PRIV;
if (type & SKB_GSO_TUNNEL_REMCSUM) {
u16 csum_start = skb_checksum_start_offset(skb);
__be16 *pd = data;
if (csum_start < hdrlen)
return -EINVAL;
csum_start -= hdrlen;
pd[0] = htons(csum_start);
pd[1] = htons(csum_start + skb->csum_offset);
if (!skb_is_gso(skb)) {
skb->ip_summed = CHECKSUM_NONE;
skb->encapsulation = 0;
}
*flags |= GUE_PFLAG_REMCSUM;
data += GUE_PLEN_REMCSUM;
}
}
fou_build_udp(skb, e, fl4, protocol, sport);
return 0;
}
EXPORT_SYMBOL(gue_build_header);
#ifdef CONFIG_NET_FOU_IP_TUNNELS
static const struct ip_tunnel_encap_ops __read_mostly fou_iptun_ops = {
.encap_hlen = fou_encap_hlen,
.build_header = fou_build_header,
};
static const struct ip_tunnel_encap_ops __read_mostly gue_iptun_ops = {
.encap_hlen = gue_encap_hlen,
.build_header = gue_build_header,
};
static int ip_tunnel_encap_add_fou_ops(void)
{
int ret;
ret = ip_tunnel_encap_add_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
if (ret < 0) {
pr_err("can't add fou ops\n");
return ret;
}
ret = ip_tunnel_encap_add_ops(&gue_iptun_ops, TUNNEL_ENCAP_GUE);
if (ret < 0) {
pr_err("can't add gue ops\n");
ip_tunnel_encap_del_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
return ret;
}
return 0;
}
static void ip_tunnel_encap_del_fou_ops(void)
{
ip_tunnel_encap_del_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
ip_tunnel_encap_del_ops(&gue_iptun_ops, TUNNEL_ENCAP_GUE);
}
#else
static int ip_tunnel_encap_add_fou_ops(void)
{
return 0;
}
static void ip_tunnel_encap_del_fou_ops(void)
{
}
#endif
static int __init fou_init(void)
{
int ret;
ret = genl_register_family_with_ops(&fou_nl_family,
fou_nl_ops);
if (ret < 0)
goto exit;
ret = ip_tunnel_encap_add_fou_ops();
if (ret < 0)
genl_unregister_family(&fou_nl_family);
exit:
return ret;
}
static void __exit fou_fini(void)
{
struct fou *fou, *next;
ip_tunnel_encap_del_fou_ops();
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");
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