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- // SPDX-License-Identifier: GPL-2.0-only
- #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/icmpv6.h>
- #include <linux/types.h>
- #include <linux/kernel.h>
- #include <net/fou.h>
- #include <net/ip.h>
- #include <net/ip6_tunnel.h>
- #include <net/ip6_checksum.h>
- #include <net/protocol.h>
- #include <net/udp.h>
- #include <net/udp_tunnel.h>
- #if IS_ENABLED(CONFIG_IPV6_FOU_TUNNEL)
- static void fou6_build_udp(struct sk_buff *skb, struct ip_tunnel_encap *e,
- struct flowi6 *fl6, 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);
- udp6_set_csum(!(e->flags & TUNNEL_ENCAP_FLAG_CSUM6), skb,
- &fl6->saddr, &fl6->daddr, skb->len);
- *protocol = IPPROTO_UDP;
- }
- static int fou6_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
- u8 *protocol, struct flowi6 *fl6)
- {
- __be16 sport;
- int err;
- int type = e->flags & TUNNEL_ENCAP_FLAG_CSUM6 ?
- SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
- err = __fou_build_header(skb, e, protocol, &sport, type);
- if (err)
- return err;
- fou6_build_udp(skb, e, fl6, protocol, sport);
- return 0;
- }
- static int gue6_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
- u8 *protocol, struct flowi6 *fl6)
- {
- __be16 sport;
- int err;
- int type = e->flags & TUNNEL_ENCAP_FLAG_CSUM6 ?
- SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
- err = __gue_build_header(skb, e, protocol, &sport, type);
- if (err)
- return err;
- fou6_build_udp(skb, e, fl6, protocol, sport);
- return 0;
- }
- static int gue6_err_proto_handler(int proto, struct sk_buff *skb,
- struct inet6_skb_parm *opt,
- u8 type, u8 code, int offset, __be32 info)
- {
- const struct inet6_protocol *ipprot;
- ipprot = rcu_dereference(inet6_protos[proto]);
- if (ipprot && ipprot->err_handler) {
- if (!ipprot->err_handler(skb, opt, type, code, offset, info))
- return 0;
- }
- return -ENOENT;
- }
- static int gue6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
- u8 type, u8 code, int offset, __be32 info)
- {
- int transport_offset = skb_transport_offset(skb);
- struct guehdr *guehdr;
- size_t len, optlen;
- int ret;
- len = sizeof(struct udphdr) + sizeof(struct guehdr);
- if (!pskb_may_pull(skb, transport_offset + len))
- return -EINVAL;
- guehdr = (struct guehdr *)&udp_hdr(skb)[1];
- switch (guehdr->version) {
- case 0: /* Full GUE header present */
- break;
- case 1: {
- /* Direct encasulation of IPv4 or IPv6 */
- skb_set_transport_header(skb, -(int)sizeof(struct icmp6hdr));
- switch (((struct iphdr *)guehdr)->version) {
- case 4:
- ret = gue6_err_proto_handler(IPPROTO_IPIP, skb, opt,
- type, code, offset, info);
- goto out;
- case 6:
- ret = gue6_err_proto_handler(IPPROTO_IPV6, skb, opt,
- type, code, offset, info);
- goto out;
- default:
- ret = -EOPNOTSUPP;
- goto out;
- }
- }
- default: /* Undefined version */
- return -EOPNOTSUPP;
- }
- if (guehdr->control)
- return -ENOENT;
- optlen = guehdr->hlen << 2;
- if (!pskb_may_pull(skb, transport_offset + len + optlen))
- return -EINVAL;
- guehdr = (struct guehdr *)&udp_hdr(skb)[1];
- if (validate_gue_flags(guehdr, optlen))
- return -EINVAL;
- /* Handling exceptions for direct UDP encapsulation in GUE would lead to
- * recursion. Besides, this kind of encapsulation can't even be
- * configured currently. Discard this.
- */
- if (guehdr->proto_ctype == IPPROTO_UDP ||
- guehdr->proto_ctype == IPPROTO_UDPLITE)
- return -EOPNOTSUPP;
- skb_set_transport_header(skb, -(int)sizeof(struct icmp6hdr));
- ret = gue6_err_proto_handler(guehdr->proto_ctype, skb,
- opt, type, code, offset, info);
- out:
- skb_set_transport_header(skb, transport_offset);
- return ret;
- }
- static const struct ip6_tnl_encap_ops fou_ip6tun_ops = {
- .encap_hlen = fou_encap_hlen,
- .build_header = fou6_build_header,
- .err_handler = gue6_err,
- };
- static const struct ip6_tnl_encap_ops gue_ip6tun_ops = {
- .encap_hlen = gue_encap_hlen,
- .build_header = gue6_build_header,
- .err_handler = gue6_err,
- };
- static int ip6_tnl_encap_add_fou_ops(void)
- {
- int ret;
- ret = ip6_tnl_encap_add_ops(&fou_ip6tun_ops, TUNNEL_ENCAP_FOU);
- if (ret < 0) {
- pr_err("can't add fou6 ops\n");
- return ret;
- }
- ret = ip6_tnl_encap_add_ops(&gue_ip6tun_ops, TUNNEL_ENCAP_GUE);
- if (ret < 0) {
- pr_err("can't add gue6 ops\n");
- ip6_tnl_encap_del_ops(&fou_ip6tun_ops, TUNNEL_ENCAP_FOU);
- return ret;
- }
- return 0;
- }
- static void ip6_tnl_encap_del_fou_ops(void)
- {
- ip6_tnl_encap_del_ops(&fou_ip6tun_ops, TUNNEL_ENCAP_FOU);
- ip6_tnl_encap_del_ops(&gue_ip6tun_ops, TUNNEL_ENCAP_GUE);
- }
- #else
- static int ip6_tnl_encap_add_fou_ops(void)
- {
- return 0;
- }
- static void ip6_tnl_encap_del_fou_ops(void)
- {
- }
- #endif
- static int __init fou6_init(void)
- {
- int ret;
- ret = ip6_tnl_encap_add_fou_ops();
- return ret;
- }
- static void __exit fou6_fini(void)
- {
- ip6_tnl_encap_del_fou_ops();
- }
- module_init(fou6_init);
- module_exit(fou6_fini);
- MODULE_AUTHOR("Tom Herbert <[email protected]>");
- MODULE_LICENSE("GPL");
- MODULE_DESCRIPTION("Foo over UDP (IPv6)");
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