1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Unstable NAT Helpers for XDP and TC-BPF hook
3 *
4 * These are called from the XDP and SCHED_CLS BPF programs. Note that it is
5 * allowed to break compatibility for these functions since the interface they
6 * are exposed through to BPF programs is explicitly unstable.
7 */
8
9 #include <linux/bpf.h>
10 #include <linux/btf_ids.h>
11 #include <net/netfilter/nf_conntrack_bpf.h>
12 #include <net/netfilter/nf_conntrack_core.h>
13 #include <net/netfilter/nf_nat.h>
14
15 __diag_push();
16 __diag_ignore_all("-Wmissing-prototypes",
17 "Global functions as their definitions will be in nf_nat BTF");
18
19 /* bpf_ct_set_nat_info - Set source or destination nat address
20 *
21 * Set source or destination nat address of the newly allocated
22 * nf_conn before insertion. This must be invoked for referenced
23 * PTR_TO_BTF_ID to nf_conn___init.
24 *
25 * Parameters:
26 * @nfct - Pointer to referenced nf_conn object, obtained using
27 * bpf_xdp_ct_alloc or bpf_skb_ct_alloc.
28 * @addr - Nat source/destination address
29 * @port - Nat source/destination port. Non-positive values are
30 * interpreted as select a random port.
31 * @manip - NF_NAT_MANIP_SRC or NF_NAT_MANIP_DST
32 */
bpf_ct_set_nat_info(struct nf_conn___init * nfct,union nf_inet_addr * addr,int port,enum nf_nat_manip_type manip)33 __bpf_kfunc int bpf_ct_set_nat_info(struct nf_conn___init *nfct,
34 union nf_inet_addr *addr, int port,
35 enum nf_nat_manip_type manip)
36 {
37 struct nf_conn *ct = (struct nf_conn *)nfct;
38 u16 proto = nf_ct_l3num(ct);
39 struct nf_nat_range2 range;
40
41 if (proto != NFPROTO_IPV4 && proto != NFPROTO_IPV6)
42 return -EINVAL;
43
44 memset(&range, 0, sizeof(struct nf_nat_range2));
45 range.flags = NF_NAT_RANGE_MAP_IPS;
46 range.min_addr = *addr;
47 range.max_addr = range.min_addr;
48 if (port > 0) {
49 range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
50 range.min_proto.all = cpu_to_be16(port);
51 range.max_proto.all = range.min_proto.all;
52 }
53
54 return nf_nat_setup_info(ct, &range, manip) == NF_DROP ? -ENOMEM : 0;
55 }
56
57 __diag_pop()
58
59 BTF_SET8_START(nf_nat_kfunc_set)
60 BTF_ID_FLAGS(func, bpf_ct_set_nat_info, KF_TRUSTED_ARGS)
61 BTF_SET8_END(nf_nat_kfunc_set)
62
63 static const struct btf_kfunc_id_set nf_bpf_nat_kfunc_set = {
64 .owner = THIS_MODULE,
65 .set = &nf_nat_kfunc_set,
66 };
67
register_nf_nat_bpf(void)68 int register_nf_nat_bpf(void)
69 {
70 int ret;
71
72 ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP,
73 &nf_bpf_nat_kfunc_set);
74 if (ret)
75 return ret;
76
77 return register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS,
78 &nf_bpf_nat_kfunc_set);
79 }
80