diff options
Diffstat (limited to 'net/ipv4/fou.c')
| -rw-r--r-- | net/ipv4/fou.c | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c new file mode 100644 index 000000000000..d44f97b79418 --- /dev/null +++ b/net/ipv4/fou.c @@ -0,0 +1,279 @@ +#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/ip.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 list_head list; +}; + +struct fou_cfg { + 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 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_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; + + /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ + fou->protocol = cfg->protocol; + fou->port = cfg->udp_config.local_udp_port; + udp_sk(sk)->encap_rcv = fou_udp_recv; + + 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; + + 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) { + 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, }, +}; + +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]); + + 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"); |