[bpf-next,v4,2/4] xfrm: interface: Add unstable helpers for setting/getting XFRM metadata from TC-BPF

Message ID	20221202095920.1659332-3-eyal.birger@gmail.com (mailing list archive)
State	New
Headers	show Return-Path: <linux-kselftest-owner@kernel.org> From: Eyal Birger <eyal.birger@gmail.com> To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, steffen.klassert@secunet.com, herbert@gondor.apana.org.au, andrii@kernel.org, daniel@iogearbox.net, nicolas.dichtel@6wind.com, razor@blackwall.org, mykolal@fb.com, ast@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, shuah@kernel.org, liuhangbin@gmail.com, lixiaoyan@google.com Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, Eyal Birger <eyal.birger@gmail.com> Subject: [PATCH bpf-next,v4 2/4] xfrm: interface: Add unstable helpers for setting/getting XFRM metadata from TC-BPF Date: Fri, 2 Dec 2022 11:59:18 +0200 Message-Id: <20221202095920.1659332-3-eyal.birger@gmail.com> In-Reply-To: <20221202095920.1659332-1-eyal.birger@gmail.com> References: <20221202095920.1659332-1-eyal.birger@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	xfrm: interface: Add unstable helpers for XFRM metadata \| expand [bpf-next,v4,0/4] xfrm: interface: Add unstable helpers for XFRM metadata [bpf-next,v4,1/4] xfrm: interface: rename xfrm_interface.c to xfrm_interface_core.c [bpf-next,v4,2/4] xfrm: interface: Add unstable helpers for setting/getting XFRM metadata from TC-B… [bpf-next,v4,3/4] tools: add IFLA_XFRM_COLLECT_METADATA to uapi/linux/if_link.h [bpf-next,v4,4/4] selftests/bpf: add xfrm_info tests

diff --git a/include/net/dst_metadata.h b/include/net/dst_metadata.h index a454cf4327fe..1b7fae4c6b24 100644 --- a/include/net/dst_metadata.h +++ b/include/net/dst_metadata.h @@ -26,6 +26,7 @@ struct macsec_info { struct xfrm_md_info { u32 if_id; int link; + struct dst_entry *dst_orig; }; struct metadata_dst { diff --git a/include/net/xfrm.h b/include/net/xfrm.h index e0cc6791c001..5e5fea3087b6 100644 --- a/include/net/xfrm.h +++ b/include/net/xfrm.h @@ -2086,4 +2086,24 @@ static inline bool xfrm6_local_dontfrag(const struct sock *sk) return false; } #endif + +#if (IS_BUILTIN(CONFIG_XFRM_INTERFACE) && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) || \ + (IS_MODULE(CONFIG_XFRM_INTERFACE) && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) + +extern int register_xfrm_interface_bpf(void); +extern void cleanup_xfrm_interface_bpf(void); + +#else + +static inline int register_xfrm_interface_bpf(void) +{ + return 0; +} + +static inline void cleanup_xfrm_interface_bpf(void) +{ +} + +#endif + #endif /* _NET_XFRM_H */ diff --git a/net/core/dst.c b/net/core/dst.c index bc9c9be4e080..bb14a0392388 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -316,6 +316,8 @@ void metadata_dst_free(struct metadata_dst *md_dst) if (md_dst->type == METADATA_IP_TUNNEL) dst_cache_destroy(&md_dst->u.tun_info.dst_cache); #endif + if (md_dst->type == METADATA_XFRM) + dst_release(md_dst->u.xfrm_info.dst_orig); kfree(md_dst); } EXPORT_SYMBOL_GPL(metadata_dst_free); @@ -340,16 +342,18 @@ EXPORT_SYMBOL_GPL(metadata_dst_alloc_percpu); void metadata_dst_free_percpu(struct metadata_dst __percpu *md_dst) { -#ifdef CONFIG_DST_CACHE int cpu; for_each_possible_cpu(cpu) { struct metadata_dst *one_md_dst = per_cpu_ptr(md_dst, cpu); +#ifdef CONFIG_DST_CACHE if (one_md_dst->type == METADATA_IP_TUNNEL) dst_cache_destroy(&one_md_dst->u.tun_info.dst_cache); - } #endif + if (one_md_dst->type == METADATA_XFRM) + dst_release(one_md_dst->u.xfrm_info.dst_orig); + } free_percpu(md_dst); } EXPORT_SYMBOL_GPL(metadata_dst_free_percpu); diff --git a/net/xfrm/Makefile b/net/xfrm/Makefile index 08a2870fdd36..cd47f88921f5 100644 --- a/net/xfrm/Makefile +++ b/net/xfrm/Makefile @@ -5,6 +5,12 @@ xfrm_interface-$(CONFIG_XFRM_INTERFACE) += xfrm_interface_core.o +ifeq ($(CONFIG_XFRM_INTERFACE),m) +xfrm_interface-$(CONFIG_DEBUG_INFO_BTF_MODULES) += xfrm_interface_bpf.o +else ifeq ($(CONFIG_XFRM_INTERFACE),y) +xfrm_interface-$(CONFIG_DEBUG_INFO_BTF) += xfrm_interface_bpf.o +endif + obj-$(CONFIG_XFRM) := xfrm_policy.o xfrm_state.o xfrm_hash.o \ xfrm_input.o xfrm_output.o \ xfrm_sysctl.o xfrm_replay.o xfrm_device.o diff --git a/net/xfrm/xfrm_interface_bpf.c b/net/xfrm/xfrm_interface_bpf.c new file mode 100644 index 000000000000..de281847c5f1 --- /dev/null +++ b/net/xfrm/xfrm_interface_bpf.c @@ -0,0 +1,123 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Unstable XFRM Helpers for TC-BPF hook + * + * These are called from 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/dst_metadata.h> +#include <net/xfrm.h> + +/* bpf_xfrm_info - XFRM metadata information + * + * Members: + * @if_id - XFRM if_id: + * Transmit: if_id to be used in policy and state lookups + * Receive: if_id of the state matched for the incoming packet + * @link - Underlying device ifindex: + * Transmit: used as the underlying device in VRF routing + * Receive: the device on which the packet had been received + */ +struct bpf_xfrm_info { + u32 if_id; + int link; +}; + +static struct metadata_dst __percpu *xfrm_md_dst; +__diag_push(); +__diag_ignore_all("-Wmissing-prototypes", + "Global functions as their definitions will be in xfrm_interface BTF"); + +/* bpf_skb_get_xfrm_info - Get XFRM metadata + * + * Parameters: + * @skb_ctx - Pointer to ctx (__sk_buff) in TC program + * Cannot be NULL + * @to - Pointer to memory to which the metadata will be copied + * Cannot be NULL + */ +__used noinline +int bpf_skb_get_xfrm_info(struct __sk_buff *skb_ctx, struct bpf_xfrm_info *to) +{ + struct sk_buff *skb = (struct sk_buff *)skb_ctx; + struct xfrm_md_info *info; + + info = skb_xfrm_md_info(skb); + if (!info) + return -EINVAL; + + to->if_id = info->if_id; + to->link = info->link; + return 0; +} + +/* bpf_skb_get_xfrm_info - Set XFRM metadata + * + * Parameters: + * @skb_ctx - Pointer to ctx (__sk_buff) in TC program + * Cannot be NULL + * @from - Pointer to memory from which the metadata will be copied + * Cannot be NULL + */ +__used noinline +int bpf_skb_set_xfrm_info(struct __sk_buff *skb_ctx, + const struct bpf_xfrm_info *from) +{ + struct sk_buff *skb = (struct sk_buff *)skb_ctx; + struct metadata_dst *md_dst; + struct xfrm_md_info *info; + + if (unlikely(skb_metadata_dst(skb))) + return -EINVAL; + + md_dst = this_cpu_ptr(xfrm_md_dst); + + info = &md_dst->u.xfrm_info; + + info->if_id = from->if_id; + info->link = from->link; + skb_dst_force(skb); + info->dst_orig = skb_dst(skb); + + dst_hold((struct dst_entry *)md_dst); + skb_dst_set(skb, (struct dst_entry *)md_dst); + return 0; +} + +__diag_pop() + +BTF_SET8_START(xfrm_ifc_kfunc_set) +BTF_ID_FLAGS(func, bpf_skb_get_xfrm_info) +BTF_ID_FLAGS(func, bpf_skb_set_xfrm_info) +BTF_SET8_END(xfrm_ifc_kfunc_set) + +static const struct btf_kfunc_id_set xfrm_interface_kfunc_set = { + .owner = THIS_MODULE, + .set = &xfrm_ifc_kfunc_set, +}; + +int __init register_xfrm_interface_bpf(void) +{ + int err; + + xfrm_md_dst = metadata_dst_alloc_percpu(0, METADATA_XFRM, + GFP_KERNEL); + if (!xfrm_md_dst) + return -ENOMEM; + err = register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, + &xfrm_interface_kfunc_set); + if (err < 0) { + metadata_dst_free_percpu(xfrm_md_dst); + return err; + } + return 0; +} + +void cleanup_xfrm_interface_bpf(void) +{ + metadata_dst_free_percpu(xfrm_md_dst); +} diff --git a/net/xfrm/xfrm_interface_core.c b/net/xfrm/xfrm_interface_core.c index 5a67b120c4db..1e1e8e965939 100644 --- a/net/xfrm/xfrm_interface_core.c +++ b/net/xfrm/xfrm_interface_core.c @@ -396,6 +396,14 @@ xfrmi_xmit2(struct sk_buff *skb, struct net_device *dev, struct flowi *fl) if_id = md_info->if_id; fl->flowi_oif = md_info->link; + if (md_info->dst_orig) { + struct dst_entry *tmp_dst = dst; + + dst = md_info->dst_orig; + skb_dst_set(skb, dst); + md_info->dst_orig = NULL; + dst_release(tmp_dst); + } } else { if_id = xi->p.if_id; } @@ -1162,12 +1170,18 @@ static int __init xfrmi_init(void) if (err < 0) goto rtnl_link_failed; + err = register_xfrm_interface_bpf(); + if (err < 0) + goto kfunc_failed; + lwtunnel_encap_add_ops(&xfrmi_encap_ops, LWTUNNEL_ENCAP_XFRM); xfrm_if_register_cb(&xfrm_if_cb); return err; +kfunc_failed: + rtnl_link_unregister(&xfrmi_link_ops); rtnl_link_failed: xfrmi6_fini(); xfrmi6_failed: @@ -1183,6 +1197,7 @@ static void __exit xfrmi_fini(void) { xfrm_if_unregister_cb(); lwtunnel_encap_del_ops(&xfrmi_encap_ops, LWTUNNEL_ENCAP_XFRM); + cleanup_xfrm_interface_bpf(); rtnl_link_unregister(&xfrmi_link_ops); xfrmi4_fini(); xfrmi6_fini();

[bpf-next,v4,2/4] xfrm: interface: Add unstable helpers for setting/getting XFRM metadata from TC-BPF

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