| // SPDX-License-Identifier: GPL-2.0-only |
| /* Unstable Conntrack Helpers for XDP and TC-BPF hook |
| * |
| * These are called from the XDP and SCHED_CLS BPF programs. Note that it is |
| * allowed to break compatibility for these functions since the interface they |
| * are exposed through to BPF programs is explicitly unstable. |
| */ |
| |
| #include <linux/bpf.h> |
| #include <linux/btf.h> |
| #include <linux/types.h> |
| #include <linux/btf_ids.h> |
| #include <linux/net_namespace.h> |
| #include <net/netfilter/nf_conntrack.h> |
| #include <net/netfilter/nf_conntrack_bpf.h> |
| #include <net/netfilter/nf_conntrack_core.h> |
| |
| /* bpf_ct_opts - Options for CT lookup helpers |
| * |
| * Members: |
| * @netns_id - Specify the network namespace for lookup |
| * Values: |
| * BPF_F_CURRENT_NETNS (-1) |
| * Use namespace associated with ctx (xdp_md, __sk_buff) |
| * [0, S32_MAX] |
| * Network Namespace ID |
| * @error - Out parameter, set for any errors encountered |
| * Values: |
| * -EINVAL - Passed NULL for bpf_tuple pointer |
| * -EINVAL - opts->reserved is not 0 |
| * -EINVAL - netns_id is less than -1 |
| * -EINVAL - opts__sz isn't NF_BPF_CT_OPTS_SZ (12) |
| * -EPROTO - l4proto isn't one of IPPROTO_TCP or IPPROTO_UDP |
| * -ENONET - No network namespace found for netns_id |
| * -ENOENT - Conntrack lookup could not find entry for tuple |
| * -EAFNOSUPPORT - tuple__sz isn't one of sizeof(tuple->ipv4) |
| * or sizeof(tuple->ipv6) |
| * @l4proto - Layer 4 protocol |
| * Values: |
| * IPPROTO_TCP, IPPROTO_UDP |
| * @reserved - Reserved member, will be reused for more options in future |
| * Values: |
| * 0 |
| */ |
| struct bpf_ct_opts { |
| s32 netns_id; |
| s32 error; |
| u8 l4proto; |
| u8 reserved[3]; |
| }; |
| |
| enum { |
| NF_BPF_CT_OPTS_SZ = 12, |
| }; |
| |
| static struct nf_conn *__bpf_nf_ct_lookup(struct net *net, |
| struct bpf_sock_tuple *bpf_tuple, |
| u32 tuple_len, u8 protonum, |
| s32 netns_id) |
| { |
| struct nf_conntrack_tuple_hash *hash; |
| struct nf_conntrack_tuple tuple; |
| |
| if (unlikely(protonum != IPPROTO_TCP && protonum != IPPROTO_UDP)) |
| return ERR_PTR(-EPROTO); |
| if (unlikely(netns_id < BPF_F_CURRENT_NETNS)) |
| return ERR_PTR(-EINVAL); |
| |
| memset(&tuple, 0, sizeof(tuple)); |
| switch (tuple_len) { |
| case sizeof(bpf_tuple->ipv4): |
| tuple.src.l3num = AF_INET; |
| tuple.src.u3.ip = bpf_tuple->ipv4.saddr; |
| tuple.src.u.tcp.port = bpf_tuple->ipv4.sport; |
| tuple.dst.u3.ip = bpf_tuple->ipv4.daddr; |
| tuple.dst.u.tcp.port = bpf_tuple->ipv4.dport; |
| break; |
| case sizeof(bpf_tuple->ipv6): |
| tuple.src.l3num = AF_INET6; |
| memcpy(tuple.src.u3.ip6, bpf_tuple->ipv6.saddr, sizeof(bpf_tuple->ipv6.saddr)); |
| tuple.src.u.tcp.port = bpf_tuple->ipv6.sport; |
| memcpy(tuple.dst.u3.ip6, bpf_tuple->ipv6.daddr, sizeof(bpf_tuple->ipv6.daddr)); |
| tuple.dst.u.tcp.port = bpf_tuple->ipv6.dport; |
| break; |
| default: |
| return ERR_PTR(-EAFNOSUPPORT); |
| } |
| |
| tuple.dst.protonum = protonum; |
| |
| if (netns_id >= 0) { |
| net = get_net_ns_by_id(net, netns_id); |
| if (unlikely(!net)) |
| return ERR_PTR(-ENONET); |
| } |
| |
| hash = nf_conntrack_find_get(net, &nf_ct_zone_dflt, &tuple); |
| if (netns_id >= 0) |
| put_net(net); |
| if (!hash) |
| return ERR_PTR(-ENOENT); |
| return nf_ct_tuplehash_to_ctrack(hash); |
| } |
| |
| __diag_push(); |
| __diag_ignore_all("-Wmissing-prototypes", |
| "Global functions as their definitions will be in nf_conntrack BTF"); |
| |
| /* bpf_xdp_ct_lookup - Lookup CT entry for the given tuple, and acquire a |
| * reference to it |
| * |
| * Parameters: |
| * @xdp_ctx - Pointer to ctx (xdp_md) in XDP program |
| * Cannot be NULL |
| * @bpf_tuple - Pointer to memory representing the tuple to look up |
| * Cannot be NULL |
| * @tuple__sz - Length of the tuple structure |
| * Must be one of sizeof(bpf_tuple->ipv4) or |
| * sizeof(bpf_tuple->ipv6) |
| * @opts - Additional options for lookup (documented above) |
| * Cannot be NULL |
| * @opts__sz - Length of the bpf_ct_opts structure |
| * Must be NF_BPF_CT_OPTS_SZ (12) |
| */ |
| struct nf_conn * |
| bpf_xdp_ct_lookup(struct xdp_md *xdp_ctx, struct bpf_sock_tuple *bpf_tuple, |
| u32 tuple__sz, struct bpf_ct_opts *opts, u32 opts__sz) |
| { |
| struct xdp_buff *ctx = (struct xdp_buff *)xdp_ctx; |
| struct net *caller_net; |
| struct nf_conn *nfct; |
| |
| BUILD_BUG_ON(sizeof(struct bpf_ct_opts) != NF_BPF_CT_OPTS_SZ); |
| |
| if (!opts) |
| return NULL; |
| if (!bpf_tuple || opts->reserved[0] || opts->reserved[1] || |
| opts->reserved[2] || opts__sz != NF_BPF_CT_OPTS_SZ) { |
| opts->error = -EINVAL; |
| return NULL; |
| } |
| caller_net = dev_net(ctx->rxq->dev); |
| nfct = __bpf_nf_ct_lookup(caller_net, bpf_tuple, tuple__sz, opts->l4proto, |
| opts->netns_id); |
| if (IS_ERR(nfct)) { |
| opts->error = PTR_ERR(nfct); |
| return NULL; |
| } |
| return nfct; |
| } |
| |
| /* bpf_skb_ct_lookup - Lookup CT entry for the given tuple, and acquire a |
| * reference to it |
| * |
| * Parameters: |
| * @skb_ctx - Pointer to ctx (__sk_buff) in TC program |
| * Cannot be NULL |
| * @bpf_tuple - Pointer to memory representing the tuple to look up |
| * Cannot be NULL |
| * @tuple__sz - Length of the tuple structure |
| * Must be one of sizeof(bpf_tuple->ipv4) or |
| * sizeof(bpf_tuple->ipv6) |
| * @opts - Additional options for lookup (documented above) |
| * Cannot be NULL |
| * @opts__sz - Length of the bpf_ct_opts structure |
| * Must be NF_BPF_CT_OPTS_SZ (12) |
| */ |
| struct nf_conn * |
| bpf_skb_ct_lookup(struct __sk_buff *skb_ctx, struct bpf_sock_tuple *bpf_tuple, |
| u32 tuple__sz, struct bpf_ct_opts *opts, u32 opts__sz) |
| { |
| struct sk_buff *skb = (struct sk_buff *)skb_ctx; |
| struct net *caller_net; |
| struct nf_conn *nfct; |
| |
| BUILD_BUG_ON(sizeof(struct bpf_ct_opts) != NF_BPF_CT_OPTS_SZ); |
| |
| if (!opts) |
| return NULL; |
| if (!bpf_tuple || opts->reserved[0] || opts->reserved[1] || |
| opts->reserved[2] || opts__sz != NF_BPF_CT_OPTS_SZ) { |
| opts->error = -EINVAL; |
| return NULL; |
| } |
| caller_net = skb->dev ? dev_net(skb->dev) : sock_net(skb->sk); |
| nfct = __bpf_nf_ct_lookup(caller_net, bpf_tuple, tuple__sz, opts->l4proto, |
| opts->netns_id); |
| if (IS_ERR(nfct)) { |
| opts->error = PTR_ERR(nfct); |
| return NULL; |
| } |
| return nfct; |
| } |
| |
| /* bpf_ct_release - Release acquired nf_conn object |
| * |
| * This must be invoked for referenced PTR_TO_BTF_ID, and the verifier rejects |
| * the program if any references remain in the program in all of the explored |
| * states. |
| * |
| * Parameters: |
| * @nf_conn - Pointer to referenced nf_conn object, obtained using |
| * bpf_xdp_ct_lookup or bpf_skb_ct_lookup. |
| */ |
| void bpf_ct_release(struct nf_conn *nfct) |
| { |
| if (!nfct) |
| return; |
| nf_ct_put(nfct); |
| } |
| |
| __diag_pop() |
| |
| BTF_SET_START(nf_ct_xdp_check_kfunc_ids) |
| BTF_ID(func, bpf_xdp_ct_lookup) |
| BTF_ID(func, bpf_ct_release) |
| BTF_SET_END(nf_ct_xdp_check_kfunc_ids) |
| |
| BTF_SET_START(nf_ct_tc_check_kfunc_ids) |
| BTF_ID(func, bpf_skb_ct_lookup) |
| BTF_ID(func, bpf_ct_release) |
| BTF_SET_END(nf_ct_tc_check_kfunc_ids) |
| |
| BTF_SET_START(nf_ct_acquire_kfunc_ids) |
| BTF_ID(func, bpf_xdp_ct_lookup) |
| BTF_ID(func, bpf_skb_ct_lookup) |
| BTF_SET_END(nf_ct_acquire_kfunc_ids) |
| |
| BTF_SET_START(nf_ct_release_kfunc_ids) |
| BTF_ID(func, bpf_ct_release) |
| BTF_SET_END(nf_ct_release_kfunc_ids) |
| |
| /* Both sets are identical */ |
| #define nf_ct_ret_null_kfunc_ids nf_ct_acquire_kfunc_ids |
| |
| static const struct btf_kfunc_id_set nf_conntrack_xdp_kfunc_set = { |
| .owner = THIS_MODULE, |
| .check_set = &nf_ct_xdp_check_kfunc_ids, |
| .acquire_set = &nf_ct_acquire_kfunc_ids, |
| .release_set = &nf_ct_release_kfunc_ids, |
| .ret_null_set = &nf_ct_ret_null_kfunc_ids, |
| }; |
| |
| static const struct btf_kfunc_id_set nf_conntrack_tc_kfunc_set = { |
| .owner = THIS_MODULE, |
| .check_set = &nf_ct_tc_check_kfunc_ids, |
| .acquire_set = &nf_ct_acquire_kfunc_ids, |
| .release_set = &nf_ct_release_kfunc_ids, |
| .ret_null_set = &nf_ct_ret_null_kfunc_ids, |
| }; |
| |
| int register_nf_conntrack_bpf(void) |
| { |
| int ret; |
| |
| ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &nf_conntrack_xdp_kfunc_set); |
| return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &nf_conntrack_tc_kfunc_set); |
| } |