bpf: tcp: Put some tcp cong functions in allowlist for bpf-tcp-cc

This patch puts some tcp cong helper functions, tcp_slow_start()
and tcp_cong_avoid_ai(), into the allowlist for the bpf-tcp-cc
program.

A few tcp cc implementation functions are also put into the
allowlist.  A potential use case is the bpf-tcp-cc implementation
may only want to override a subset of a tcp_congestion_ops.  For others,
the bpf-tcp-cc can directly call the kernel counter parts instead of
re-implementing (or copy-and-pasting) them to the bpf program.

They will only be available to the bpf-tcp-cc typed program.
The allowlist functions are not bounded to a fixed ABI contract.
When any of them has changed, the bpf-tcp-cc program has to be changed
like any in-tree/out-of-tree kernel tcp-cc implementations do also.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210325015201.1546345-1-kafai@fb.com
This commit is contained in:
Martin KaFai Lau 2021-03-24 18:52:01 -07:00 коммит произвёл Alexei Starovoitov
Родитель d22f6ad187
Коммит e78aea8b21
1 изменённых файлов: 41 добавлений и 0 удалений

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@ -5,6 +5,7 @@
#include <linux/bpf_verifier.h>
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/btf_ids.h>
#include <linux/filter.h>
#include <net/tcp.h>
#include <net/bpf_sk_storage.h>
@ -178,10 +179,50 @@ bpf_tcp_ca_get_func_proto(enum bpf_func_id func_id,
}
}
BTF_SET_START(bpf_tcp_ca_kfunc_ids)
BTF_ID(func, tcp_reno_ssthresh)
BTF_ID(func, tcp_reno_cong_avoid)
BTF_ID(func, tcp_reno_undo_cwnd)
BTF_ID(func, tcp_slow_start)
BTF_ID(func, tcp_cong_avoid_ai)
#if IS_BUILTIN(CONFIG_TCP_CONG_CUBIC)
BTF_ID(func, cubictcp_init)
BTF_ID(func, cubictcp_recalc_ssthresh)
BTF_ID(func, cubictcp_cong_avoid)
BTF_ID(func, cubictcp_state)
BTF_ID(func, cubictcp_cwnd_event)
BTF_ID(func, cubictcp_acked)
#endif
#if IS_BUILTIN(CONFIG_TCP_CONG_DCTCP)
BTF_ID(func, dctcp_init)
BTF_ID(func, dctcp_update_alpha)
BTF_ID(func, dctcp_cwnd_event)
BTF_ID(func, dctcp_ssthresh)
BTF_ID(func, dctcp_cwnd_undo)
BTF_ID(func, dctcp_state)
#endif
#if IS_BUILTIN(CONFIG_TCP_CONG_BBR)
BTF_ID(func, bbr_init)
BTF_ID(func, bbr_main)
BTF_ID(func, bbr_sndbuf_expand)
BTF_ID(func, bbr_undo_cwnd)
BTF_ID(func, bbr_cwnd_even),
BTF_ID(func, bbr_ssthresh)
BTF_ID(func, bbr_min_tso_segs)
BTF_ID(func, bbr_set_state)
#endif
BTF_SET_END(bpf_tcp_ca_kfunc_ids)
static bool bpf_tcp_ca_check_kfunc_call(u32 kfunc_btf_id)
{
return btf_id_set_contains(&bpf_tcp_ca_kfunc_ids, kfunc_btf_id);
}
static const struct bpf_verifier_ops bpf_tcp_ca_verifier_ops = {
.get_func_proto = bpf_tcp_ca_get_func_proto,
.is_valid_access = bpf_tcp_ca_is_valid_access,
.btf_struct_access = bpf_tcp_ca_btf_struct_access,
.check_kfunc_call = bpf_tcp_ca_check_kfunc_call,
};
static int bpf_tcp_ca_init_member(const struct btf_type *t,