[v2,bpf-next,3/4] bpf: Allow using bpf_sk_storage in FENTRY/FEXIT/RAW_TP

Message ID	20201112211313.2587383-1-kafai@fb.com
State	Superseded
Headers	show Return-Path: <netdev-owner@vger.kernel.org> From: Martin KaFai Lau <kafai@fb.com> To: <bpf@vger.kernel.org> CC: Alexei Starovoitov <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>, <kernel-team@fb.com>, <netdev@vger.kernel.org>, Song Liu <songliubraving@fb.com> Subject: [PATCH v2 bpf-next 3/4] bpf: Allow using bpf_sk_storage in FENTRY/FEXIT/RAW_TP Date: Thu, 12 Nov 2020 13:13:13 -0800 Message-ID: <20201112211313.2587383-1-kafai@fb.com> In-Reply-To: <20201112211255.2585961-1-kafai@fb.com> References: <20201112211255.2585961-1-kafai@fb.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain Precedence: bulk
Series	bpf: Enable bpf_sk_storage for FENTRY/FEXIT/RAW_TP \| expand [v2,bpf-next,0/4] bpf: Enable bpf_sk_storage for FENTRY/FEXIT/RAW_TP [v2,bpf-next,1/4] bpf: Folding omem_charge() into sk_storage_charge() [v2,bpf-next,2/4] bpf: Rename some functions in bpf_sk_storage [v2,bpf-next,3/4] bpf: Allow using bpf_sk_storage in FENTRY/FEXIT/RAW_TP [v2,bpf-next,4/4] bpf: selftest: Use bpf_sk_storage in FENTRY/FEXIT/RAW_TP

diff --git a/include/net/bpf_sk_storage.h b/include/net/bpf_sk_storage.h index 3c516dd07caf..0e85713f56df 100644 --- a/include/net/bpf_sk_storage.h +++ b/include/net/bpf_sk_storage.h @@ -20,6 +20,8 @@ void bpf_sk_storage_free(struct sock *sk); extern const struct bpf_func_proto bpf_sk_storage_get_proto; extern const struct bpf_func_proto bpf_sk_storage_delete_proto; +extern const struct bpf_func_proto bpf_sk_storage_get_tracing_proto; +extern const struct bpf_func_proto bpf_sk_storage_delete_tracing_proto; struct bpf_local_storage_elem; struct bpf_sk_storage_diag; diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index e4515b0f62a8..cfce60ad1cb5 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -16,6 +16,7 @@ #include <linux/syscalls.h> #include <linux/error-injection.h> #include <linux/btf_ids.h> +#include <net/bpf_sk_storage.h> #include <uapi/linux/bpf.h> #include <uapi/linux/btf.h> @@ -1735,6 +1736,10 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_skc_to_tcp_request_sock_proto; case BPF_FUNC_skc_to_udp6_sock: return &bpf_skc_to_udp6_sock_proto; + case BPF_FUNC_sk_storage_get: + return &bpf_sk_storage_get_tracing_proto; + case BPF_FUNC_sk_storage_delete: + return &bpf_sk_storage_delete_tracing_proto; #endif case BPF_FUNC_seq_printf: return prog->expected_attach_type == BPF_TRACE_ITER ? diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index fd416678f236..359908a7d3c1 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -6,6 +6,7 @@ #include <linux/types.h> #include <linux/spinlock.h> #include <linux/bpf.h> +#include <linux/btf.h> #include <linux/btf_ids.h> #include <linux/bpf_local_storage.h> #include <net/bpf_sk_storage.h> @@ -378,6 +379,79 @@ const struct bpf_func_proto bpf_sk_storage_delete_proto = { .arg2_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON, }; +static bool bpf_sk_storage_tracing_allowed(const struct bpf_prog *prog) +{ + const struct btf *btf_vmlinux; + const struct btf_type *t; + const char *tname; + u32 btf_id; + + if (prog->aux->dst_prog) + return false; + + /* Ensure the tracing program is not tracing + * any bpf_sk_storage*() function and also + * use the bpf_sk_storage_(get|delete) helper. + */ + switch (prog->expected_attach_type) { + case BPF_TRACE_RAW_TP: + /* bpf_sk_storage has no trace point */ + return true; + case BPF_TRACE_FENTRY: + case BPF_TRACE_FEXIT: + btf_vmlinux = bpf_get_btf_vmlinux(); + btf_id = prog->aux->attach_btf_id; + t = btf_type_by_id(btf_vmlinux, btf_id); + tname = btf_name_by_offset(btf_vmlinux, t->name_off); + return !!strncmp(tname, "bpf_sk_storage", + strlen("bpf_sk_storage")); + default: + return false; + } + + return false; +} + +BPF_CALL_4(bpf_sk_storage_get_tracing, struct bpf_map *, map, struct sock *, sk, + void *, value, u64, flags) +{ + if (!in_serving_softirq() && !in_task()) + return (unsigned long)NULL; + + return (unsigned long)____bpf_sk_storage_get(map, sk, value, flags); +} + +BPF_CALL_2(bpf_sk_storage_delete_tracing, struct bpf_map *, map, + struct sock *, sk) +{ + if (!in_serving_softirq() && !in_task()) + return -EPERM; + + return ____bpf_sk_storage_delete(map, sk); +} + +const struct bpf_func_proto bpf_sk_storage_get_tracing_proto = { + .func = bpf_sk_storage_get_tracing, + .gpl_only = false, + .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_BTF_ID, + .arg2_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], + .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL, + .arg4_type = ARG_ANYTHING, + .allowed = bpf_sk_storage_tracing_allowed, +}; + +const struct bpf_func_proto bpf_sk_storage_delete_tracing_proto = { + .func = bpf_sk_storage_delete_tracing, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_BTF_ID, + .arg2_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], + .allowed = bpf_sk_storage_tracing_allowed, +}; + struct bpf_sk_storage_diag { u32 nr_maps; struct bpf_map *maps[];

[v2,bpf-next,3/4] bpf: Allow using bpf_sk_storage in FENTRY/FEXIT/RAW_TP

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