Hi!
The patch leads to
depmod: ERROR: Cycle detected: nf_conntrack -> nf_nat -> nf_conntrack
when it is built as modules (due to nf_nat_setup_info() dependency)
On Sun, Sep 25, 2022 at 4:26 PM Lorenzo Bianconi <lorenzo@xxxxxxxxxx> wrote:
>
> Remove circular dependency between nf_nat module and nf_conntrack one
> moving bpf_ct_set_nat_info kfunc in nf_nat_bpf.c
>
> Fixes: 0fabd2aa199f ("net: netfilter: add bpf_ct_set_nat_info kfunc helper")
> Suggested-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
> Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx>
> Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
> ---
> include/net/netfilter/nf_conntrack_bpf.h | 5 ++
> include/net/netfilter/nf_nat.h | 14 +++++
> net/netfilter/Makefile | 6 ++
> net/netfilter/nf_conntrack_bpf.c | 49 ---------------
> net/netfilter/nf_nat_bpf.c | 79 ++++++++++++++++++++++++
> net/netfilter/nf_nat_core.c | 2 +-
> 6 files changed, 105 insertions(+), 50 deletions(-)
> create mode 100644 net/netfilter/nf_nat_bpf.c
>
> diff --git a/include/net/netfilter/nf_conntrack_bpf.h b/include/net/netfilter/nf_conntrack_bpf.h
> index c8b80add1142..1ce46e406062 100644
> --- a/include/net/netfilter/nf_conntrack_bpf.h
> +++ b/include/net/netfilter/nf_conntrack_bpf.h
> @@ -4,6 +4,11 @@
> #define _NF_CONNTRACK_BPF_H
>
> #include <linux/kconfig.h>
> +#include <net/netfilter/nf_conntrack.h>
> +
> +struct nf_conn___init {
> + struct nf_conn ct;
> +};
>
> #if (IS_BUILTIN(CONFIG_NF_CONNTRACK) && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) || \
> (IS_MODULE(CONFIG_NF_CONNTRACK) && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES))
> diff --git a/include/net/netfilter/nf_nat.h b/include/net/netfilter/nf_nat.h
> index e9eb01e99d2f..cd084059a953 100644
> --- a/include/net/netfilter/nf_nat.h
> +++ b/include/net/netfilter/nf_nat.h
> @@ -68,6 +68,20 @@ static inline bool nf_nat_oif_changed(unsigned int hooknum,
> #endif
> }
>
> +#if (IS_BUILTIN(CONFIG_NF_NAT) && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) || \
> + (IS_MODULE(CONFIG_NF_NAT) && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES))
> +
> +extern int register_nf_nat_bpf(void);
> +
> +#else
> +
> +static inline int register_nf_nat_bpf(void)
> +{
> + return 0;
> +}
> +
> +#endif
> +
> int nf_nat_register_fn(struct net *net, u8 pf, const struct nf_hook_ops *ops,
> const struct nf_hook_ops *nat_ops, unsigned int ops_count);
> void nf_nat_unregister_fn(struct net *net, u8 pf, const struct nf_hook_ops *ops,
> diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
> index 06df49ea6329..0f060d100880 100644
> --- a/net/netfilter/Makefile
> +++ b/net/netfilter/Makefile
> @@ -60,6 +60,12 @@ obj-$(CONFIG_NF_NAT) += nf_nat.o
> nf_nat-$(CONFIG_NF_NAT_REDIRECT) += nf_nat_redirect.o
> nf_nat-$(CONFIG_NF_NAT_MASQUERADE) += nf_nat_masquerade.o
>
> +ifeq ($(CONFIG_NF_NAT),m)
> +nf_nat-$(CONFIG_DEBUG_INFO_BTF_MODULES) += nf_nat_bpf.o
> +else ifeq ($(CONFIG_NF_NAT),y)
> +nf_nat-$(CONFIG_DEBUG_INFO_BTF) += nf_nat_bpf.o
> +endif
> +
> # NAT helpers
> obj-$(CONFIG_NF_NAT_AMANDA) += nf_nat_amanda.o
> obj-$(CONFIG_NF_NAT_FTP) += nf_nat_ftp.o
> diff --git a/net/netfilter/nf_conntrack_bpf.c b/net/netfilter/nf_conntrack_bpf.c
> index 756ea818574e..f4ba4ff3a63b 100644
> --- a/net/netfilter/nf_conntrack_bpf.c
> +++ b/net/netfilter/nf_conntrack_bpf.c
> @@ -14,7 +14,6 @@
> #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>
> #include <net/netfilter/nf_nat.h>
> @@ -239,10 +238,6 @@ __diag_push();
> __diag_ignore_all("-Wmissing-prototypes",
> "Global functions as their definitions will be in nf_conntrack BTF");
>
> -struct nf_conn___init {
> - struct nf_conn ct;
> -};
> -
> /* bpf_xdp_ct_alloc - Allocate a new CT entry
> *
> * Parameters:
> @@ -476,49 +471,6 @@ int bpf_ct_change_status(struct nf_conn *nfct, u32 status)
> return nf_ct_change_status_common(nfct, status);
> }
>
> -/* bpf_ct_set_nat_info - Set source or destination nat address
> - *
> - * Set source or destination nat address of the newly allocated
> - * nf_conn before insertion. This must be invoked for referenced
> - * PTR_TO_BTF_ID to nf_conn___init.
> - *
> - * Parameters:
> - * @nfct - Pointer to referenced nf_conn object, obtained using
> - * bpf_xdp_ct_alloc or bpf_skb_ct_alloc.
> - * @addr - Nat source/destination address
> - * @port - Nat source/destination port. Non-positive values are
> - * interpreted as select a random port.
> - * @manip - NF_NAT_MANIP_SRC or NF_NAT_MANIP_DST
> - */
> -int bpf_ct_set_nat_info(struct nf_conn___init *nfct,
> - union nf_inet_addr *addr, int port,
> - enum nf_nat_manip_type manip)
> -{
> -#if ((IS_MODULE(CONFIG_NF_NAT) && IS_MODULE(CONFIG_NF_CONNTRACK)) || \
> - IS_BUILTIN(CONFIG_NF_NAT))
> - struct nf_conn *ct = (struct nf_conn *)nfct;
> - u16 proto = nf_ct_l3num(ct);
> - struct nf_nat_range2 range;
> -
> - if (proto != NFPROTO_IPV4 && proto != NFPROTO_IPV6)
> - return -EINVAL;
> -
> - memset(&range, 0, sizeof(struct nf_nat_range2));
> - range.flags = NF_NAT_RANGE_MAP_IPS;
> - range.min_addr = *addr;
> - range.max_addr = range.min_addr;
> - if (port > 0) {
> - range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
> - range.min_proto.all = cpu_to_be16(port);
> - range.max_proto.all = range.min_proto.all;
> - }
> -
> - return nf_nat_setup_info(ct, &range, manip) == NF_DROP ? -ENOMEM : 0;
> -#else
> - return -EOPNOTSUPP;
> -#endif
> -}
> -
> __diag_pop()
>
> BTF_SET8_START(nf_ct_kfunc_set)
> @@ -532,7 +484,6 @@ BTF_ID_FLAGS(func, bpf_ct_set_timeout, KF_TRUSTED_ARGS)
> BTF_ID_FLAGS(func, bpf_ct_change_timeout, KF_TRUSTED_ARGS)
> BTF_ID_FLAGS(func, bpf_ct_set_status, KF_TRUSTED_ARGS)
> BTF_ID_FLAGS(func, bpf_ct_change_status, KF_TRUSTED_ARGS)
> -BTF_ID_FLAGS(func, bpf_ct_set_nat_info, KF_TRUSTED_ARGS)
> BTF_SET8_END(nf_ct_kfunc_set)
>
> static const struct btf_kfunc_id_set nf_conntrack_kfunc_set = {
> diff --git a/net/netfilter/nf_nat_bpf.c b/net/netfilter/nf_nat_bpf.c
> new file mode 100644
> index 000000000000..0fa5a0bbb0ff
> --- /dev/null
> +++ b/net/netfilter/nf_nat_bpf.c
> @@ -0,0 +1,79 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/* Unstable NAT 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_ids.h>
> +#include <net/netfilter/nf_conntrack_bpf.h>
> +#include <net/netfilter/nf_conntrack_core.h>
> +#include <net/netfilter/nf_nat.h>
> +
> +__diag_push();
> +__diag_ignore_all("-Wmissing-prototypes",
> + "Global functions as their definitions will be in nf_nat BTF");
> +
> +/* bpf_ct_set_nat_info - Set source or destination nat address
> + *
> + * Set source or destination nat address of the newly allocated
> + * nf_conn before insertion. This must be invoked for referenced
> + * PTR_TO_BTF_ID to nf_conn___init.
> + *
> + * Parameters:
> + * @nfct - Pointer to referenced nf_conn object, obtained using
> + * bpf_xdp_ct_alloc or bpf_skb_ct_alloc.
> + * @addr - Nat source/destination address
> + * @port - Nat source/destination port. Non-positive values are
> + * interpreted as select a random port.
> + * @manip - NF_NAT_MANIP_SRC or NF_NAT_MANIP_DST
> + */
> +int bpf_ct_set_nat_info(struct nf_conn___init *nfct,
> + union nf_inet_addr *addr, int port,
> + enum nf_nat_manip_type manip)
> +{
> + struct nf_conn *ct = (struct nf_conn *)nfct;
> + u16 proto = nf_ct_l3num(ct);
> + struct nf_nat_range2 range;
> +
> + if (proto != NFPROTO_IPV4 && proto != NFPROTO_IPV6)
> + return -EINVAL;
> +
> + memset(&range, 0, sizeof(struct nf_nat_range2));
> + range.flags = NF_NAT_RANGE_MAP_IPS;
> + range.min_addr = *addr;
> + range.max_addr = range.min_addr;
> + if (port > 0) {
> + range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
> + range.min_proto.all = cpu_to_be16(port);
> + range.max_proto.all = range.min_proto.all;
> + }
> +
> + return nf_nat_setup_info(ct, &range, manip) == NF_DROP ? -ENOMEM : 0;
> +}
> +
> +__diag_pop()
> +
> +BTF_SET8_START(nf_nat_kfunc_set)
> +BTF_ID_FLAGS(func, bpf_ct_set_nat_info, KF_TRUSTED_ARGS)
> +BTF_SET8_END(nf_nat_kfunc_set)
> +
> +static const struct btf_kfunc_id_set nf_bpf_nat_kfunc_set = {
> + .owner = THIS_MODULE,
> + .set = &nf_nat_kfunc_set,
> +};
> +
> +int register_nf_nat_bpf(void)
> +{
> + int ret;
> +
> + ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP,
> + &nf_bpf_nat_kfunc_set);
> + if (ret)
> + return ret;
> +
> + return register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS,
> + &nf_bpf_nat_kfunc_set);
> +}
> diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
> index 7981be526f26..1ed09c9af5e5 100644
> --- a/net/netfilter/nf_nat_core.c
> +++ b/net/netfilter/nf_nat_core.c
> @@ -1152,7 +1152,7 @@ static int __init nf_nat_init(void)
> WARN_ON(nf_nat_hook != NULL);
> RCU_INIT_POINTER(nf_nat_hook, &nat_hook);
>
> - return 0;
> + return register_nf_nat_bpf();
> }
>
> static void __exit nf_nat_cleanup(void)
> --
> 2.37.3
>
--
WBR, Yauheni
