On Fri, Dec 22, 2023 at 08:21:46PM +0800, Philo Lu wrote: > Like perfbuf/ringbuf, a helper is needed to write into the buffer, named > bpf_relay_output, whose usage is same as ringbuf. Note that it works only > after relay files are set, i.e., after calling map_update_elem for the > created relay map.
we can't add helpers anymore, this will need to be kfunc check functions marked with __bpf_kfunc as examples jirka > > Signed-off-by: Philo Lu <[email protected]> > --- > include/linux/bpf.h | 1 + > include/uapi/linux/bpf.h | 10 ++++++++++ > kernel/bpf/helpers.c | 4 ++++ > kernel/bpf/relaymap.c | 26 ++++++++++++++++++++++++++ > kernel/bpf/verifier.c | 8 ++++++++ > kernel/trace/bpf_trace.c | 4 ++++ > 6 files changed, 53 insertions(+) > > diff --git a/include/linux/bpf.h b/include/linux/bpf.h > index 7671530d6e4e..b177122369e6 100644 > --- a/include/linux/bpf.h > +++ b/include/linux/bpf.h > @@ -3095,6 +3095,7 @@ extern const struct bpf_func_proto bpf_get_retval_proto; > extern const struct bpf_func_proto bpf_user_ringbuf_drain_proto; > extern const struct bpf_func_proto bpf_cgrp_storage_get_proto; > extern const struct bpf_func_proto bpf_cgrp_storage_delete_proto; > +extern const struct bpf_func_proto bpf_relay_output_proto; > > const struct bpf_func_proto *tracing_prog_func_proto( > enum bpf_func_id func_id, const struct bpf_prog *prog); > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > index 143b75676bd3..03c0c1953ba1 100644 > --- a/include/uapi/linux/bpf.h > +++ b/include/uapi/linux/bpf.h > @@ -5686,6 +5686,15 @@ union bpf_attr { > * 0 on success. > * > * **-ENOENT** if the bpf_local_storage cannot be found. > + * > + * long bpf_relay_output(void *map, void *data, u64 size, u64 flags) > + * Description > + * Copy *size* bytes from *data* into *map* of type > BPF_MAP_TYPE_RELAY. > + * Currently, the *flags* must be 0. > + * Return > + * 0 on success. > + * > + * **-ENOENT** if the relay base_file in debugfs cannot be found. > */ > #define ___BPF_FUNC_MAPPER(FN, ctx...) \ > FN(unspec, 0, ##ctx) \ > @@ -5900,6 +5909,7 @@ union bpf_attr { > FN(user_ringbuf_drain, 209, ##ctx) \ > FN(cgrp_storage_get, 210, ##ctx) \ > FN(cgrp_storage_delete, 211, ##ctx) \ > + FN(relay_output, 212, ##ctx) \ > /* */ > > /* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't > diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c > index be72824f32b2..0c26e87ce729 100644 > --- a/kernel/bpf/helpers.c > +++ b/kernel/bpf/helpers.c > @@ -1720,6 +1720,10 @@ bpf_base_func_proto(enum bpf_func_id func_id) > return &bpf_ringbuf_discard_proto; > case BPF_FUNC_ringbuf_query: > return &bpf_ringbuf_query_proto; > +#ifdef CONFIG_RELAY > + case BPF_FUNC_relay_output: > + return &bpf_relay_output_proto; > +#endif > case BPF_FUNC_strncmp: > return &bpf_strncmp_proto; > case BPF_FUNC_strtol: > diff --git a/kernel/bpf/relaymap.c b/kernel/bpf/relaymap.c > index 588c8de0a4bd..f9e2e4a780df 100644 > --- a/kernel/bpf/relaymap.c > +++ b/kernel/bpf/relaymap.c > @@ -173,6 +173,32 @@ static u64 relay_map_mem_usage(const struct bpf_map *map) > return usage; > } > > +BPF_CALL_4(bpf_relay_output, struct bpf_map *, map, void *, data, u64, size, > + u64, flags) > +{ > + struct bpf_relay_map *rmap; > + > + /* not support any flag now */ > + if (unlikely(flags)) > + return -EINVAL; > + > + rmap = container_of(map, struct bpf_relay_map, map); > + if (!rmap->relay_chan->has_base_filename) > + return -ENOENT; > + > + relay_write(rmap->relay_chan, data, size); > + return 0; > +} > + > +const struct bpf_func_proto bpf_relay_output_proto = { > + .func = bpf_relay_output, > + .ret_type = RET_INTEGER, > + .arg1_type = ARG_CONST_MAP_PTR, > + .arg2_type = ARG_PTR_TO_MEM | MEM_RDONLY, > + .arg3_type = ARG_CONST_SIZE_OR_ZERO, > + .arg4_type = ARG_ANYTHING, > +}; > + > BTF_ID_LIST_SINGLE(relay_map_btf_ids, struct, bpf_relay_map) > const struct bpf_map_ops relay_map_ops = { > .map_meta_equal = bpf_map_meta_equal, > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > index f13008d27f35..8c8287d6ae18 100644 > --- a/kernel/bpf/verifier.c > +++ b/kernel/bpf/verifier.c > @@ -8800,6 +8800,10 @@ static int check_map_func_compatibility(struct > bpf_verifier_env *env, > if (func_id != BPF_FUNC_user_ringbuf_drain) > goto error; > break; > + case BPF_MAP_TYPE_RELAY: > + if (func_id != BPF_FUNC_relay_output) > + goto error; > + break; > case BPF_MAP_TYPE_STACK_TRACE: > if (func_id != BPF_FUNC_get_stackid) > goto error; > @@ -8932,6 +8936,10 @@ static int check_map_func_compatibility(struct > bpf_verifier_env *env, > if (map->map_type != BPF_MAP_TYPE_USER_RINGBUF) > goto error; > break; > + case BPF_FUNC_relay_output: > + if (map->map_type != BPF_MAP_TYPE_RELAY) > + goto error; > + break; > case BPF_FUNC_get_stackid: > if (map->map_type != BPF_MAP_TYPE_STACK_TRACE) > goto error; > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > index 7ac6c52b25eb..5b13553c6232 100644 > --- a/kernel/trace/bpf_trace.c > +++ b/kernel/trace/bpf_trace.c > @@ -1594,6 +1594,10 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const > struct bpf_prog *prog) > return &bpf_ringbuf_discard_proto; > case BPF_FUNC_ringbuf_query: > return &bpf_ringbuf_query_proto; > +#ifdef CONFIG_RELAY > + case BPF_FUNC_relay_output: > + return &bpf_relay_output_proto; > +#endif > case BPF_FUNC_jiffies64: > return &bpf_jiffies64_proto; > case BPF_FUNC_get_task_stack: > -- > 2.32.0.3.g01195cf9f >
