blob: 0dcee9df13268930f699931304be795bfd6db259 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2019 Facebook */
#include <linux/types.h>
#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>
/* "extern" is to avoid sparse warning. It is only used in bpf_struct_ops.c. */
extern struct bpf_struct_ops bpf_tcp_congestion_ops;
static u32 optional_ops[] = {
offsetof(struct tcp_congestion_ops, init),
offsetof(struct tcp_congestion_ops, release),
offsetof(struct tcp_congestion_ops, set_state),
offsetof(struct tcp_congestion_ops, cwnd_event),
offsetof(struct tcp_congestion_ops, in_ack_event),
offsetof(struct tcp_congestion_ops, pkts_acked),
offsetof(struct tcp_congestion_ops, min_tso_segs),
offsetof(struct tcp_congestion_ops, sndbuf_expand),
offsetof(struct tcp_congestion_ops, cong_control),
static u32 unsupported_ops[] = {
offsetof(struct tcp_congestion_ops, get_info),
static const struct btf_type *tcp_sock_type;
static u32 tcp_sock_id, sock_id;
static int bpf_tcp_ca_init(struct btf *btf)
s32 type_id;
type_id = btf_find_by_name_kind(btf, "sock", BTF_KIND_STRUCT);
if (type_id < 0)
return -EINVAL;
sock_id = type_id;
type_id = btf_find_by_name_kind(btf, "tcp_sock", BTF_KIND_STRUCT);
if (type_id < 0)
return -EINVAL;
tcp_sock_id = type_id;
tcp_sock_type = btf_type_by_id(btf, tcp_sock_id);
return 0;
static bool is_optional(u32 member_offset)
unsigned int i;
for (i = 0; i < ARRAY_SIZE(optional_ops); i++) {
if (member_offset == optional_ops[i])
return true;
return false;
static bool is_unsupported(u32 member_offset)
unsigned int i;
for (i = 0; i < ARRAY_SIZE(unsupported_ops); i++) {
if (member_offset == unsupported_ops[i])
return true;
return false;
extern struct btf *btf_vmlinux;
static bool bpf_tcp_ca_is_valid_access(int off, int size,
enum bpf_access_type type,
const struct bpf_prog *prog,
struct bpf_insn_access_aux *info)
if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS)
return false;
if (type != BPF_READ)
return false;
if (off % size != 0)
return false;
if (!btf_ctx_access(off, size, type, prog, info))
return false;
if (info->reg_type == PTR_TO_BTF_ID && info->btf_id == sock_id)
/* promote it to tcp_sock */
info->btf_id = tcp_sock_id;
return true;
static int bpf_tcp_ca_btf_struct_access(struct bpf_verifier_log *log,
const struct btf *btf,
const struct btf_type *t, int off,
int size, enum bpf_access_type atype,
u32 *next_btf_id)
size_t end;
if (atype == BPF_READ)
return btf_struct_access(log, btf, t, off, size, atype, next_btf_id);
if (t != tcp_sock_type) {
bpf_log(log, "only read is supported\n");
return -EACCES;
switch (off) {
case bpf_ctx_range(struct inet_connection_sock, icsk_ca_priv):
end = offsetofend(struct inet_connection_sock, icsk_ca_priv);
case offsetof(struct inet_connection_sock, icsk_ack.pending):
end = offsetofend(struct inet_connection_sock,
case offsetof(struct tcp_sock, snd_cwnd):
end = offsetofend(struct tcp_sock, snd_cwnd);
case offsetof(struct tcp_sock, snd_cwnd_cnt):
end = offsetofend(struct tcp_sock, snd_cwnd_cnt);
case offsetof(struct tcp_sock, snd_ssthresh):
end = offsetofend(struct tcp_sock, snd_ssthresh);
case offsetof(struct tcp_sock, ecn_flags):
end = offsetofend(struct tcp_sock, ecn_flags);
bpf_log(log, "no write support to tcp_sock at off %d\n", off);
return -EACCES;
if (off + size > end) {
"write access at off %d with size %d beyond the member of tcp_sock ended at %zu\n",
off, size, end);
return -EACCES;
return NOT_INIT;
BPF_CALL_2(bpf_tcp_send_ack, struct tcp_sock *, tp, u32, rcv_nxt)
/* bpf_tcp_ca prog cannot have NULL tp */
__tcp_send_ack((struct sock *)tp, rcv_nxt);
return 0;
static const struct bpf_func_proto bpf_tcp_send_ack_proto = {
.func = bpf_tcp_send_ack,
.gpl_only = false,
/* In case we want to report error later */
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_BTF_ID,
.arg1_btf_id = &tcp_sock_id,
.arg2_type = ARG_ANYTHING,
static u32 prog_ops_moff(const struct bpf_prog *prog)
const struct btf_member *m;
const struct btf_type *t;
u32 midx;
midx = prog->expected_attach_type;
t = bpf_tcp_congestion_ops.type;
m = &btf_type_member(t)[midx];
return btf_member_bit_offset(t, m) / 8;
static const struct bpf_func_proto *
bpf_tcp_ca_get_func_proto(enum bpf_func_id func_id,
const struct bpf_prog *prog)
switch (func_id) {
case BPF_FUNC_tcp_send_ack:
return &bpf_tcp_send_ack_proto;
case BPF_FUNC_sk_storage_get:
return &bpf_sk_storage_get_proto;
case BPF_FUNC_sk_storage_delete:
return &bpf_sk_storage_delete_proto;
case BPF_FUNC_setsockopt:
/* Does not allow release() to call setsockopt.
* release() is called when the current bpf-tcp-cc
* is retiring. It is not allowed to call
* setsockopt() to make further changes which
* may potentially allocate new resources.
if (prog_ops_moff(prog) !=
offsetof(struct tcp_congestion_ops, release))
return &bpf_sk_setsockopt_proto;
return NULL;
case BPF_FUNC_getsockopt:
/* Since get/setsockopt is usually expected to
* be available together, disable getsockopt for
* release also to avoid usage surprise.
* The bpf-tcp-cc already has a more powerful way
* to read tcp_sock from the PTR_TO_BTF_ID.
if (prog_ops_moff(prog) !=
offsetof(struct tcp_congestion_ops, release))
return &bpf_sk_getsockopt_proto;
return NULL;
return bpf_base_func_proto(func_id);
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)
#ifdef CONFIG_X86
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)
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)
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_event)
BTF_ID(func, bbr_ssthresh)
BTF_ID(func, bbr_min_tso_segs)
BTF_ID(func, bbr_set_state)
#endif /* CONFIG_X86 */
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,
const struct btf_member *member,
void *kdata, const void *udata)
const struct tcp_congestion_ops *utcp_ca;
struct tcp_congestion_ops *tcp_ca;
int prog_fd;
u32 moff;
utcp_ca = (const struct tcp_congestion_ops *)udata;
tcp_ca = (struct tcp_congestion_ops *)kdata;
moff = btf_member_bit_offset(t, member) / 8;
switch (moff) {
case offsetof(struct tcp_congestion_ops, flags):
if (utcp_ca->flags & ~TCP_CONG_MASK)
return -EINVAL;
tcp_ca->flags = utcp_ca->flags;
return 1;
case offsetof(struct tcp_congestion_ops, name):
if (bpf_obj_name_cpy(tcp_ca->name, utcp_ca->name,
sizeof(tcp_ca->name)) <= 0)
return -EINVAL;
if (tcp_ca_find(utcp_ca->name))
return -EEXIST;
return 1;
if (!btf_type_resolve_func_ptr(btf_vmlinux, member->type, NULL))
return 0;
/* Ensure bpf_prog is provided for compulsory func ptr */
prog_fd = (int)(*(unsigned long *)(udata + moff));
if (!prog_fd && !is_optional(moff) && !is_unsupported(moff))
return -EINVAL;
return 0;
static int bpf_tcp_ca_check_member(const struct btf_type *t,
const struct btf_member *member)
if (is_unsupported(btf_member_bit_offset(t, member) / 8))
return -ENOTSUPP;
return 0;
static int bpf_tcp_ca_reg(void *kdata)
return tcp_register_congestion_control(kdata);
static void bpf_tcp_ca_unreg(void *kdata)
struct bpf_struct_ops bpf_tcp_congestion_ops = {
.verifier_ops = &bpf_tcp_ca_verifier_ops,
.reg = bpf_tcp_ca_reg,
.unreg = bpf_tcp_ca_unreg,
.check_member = bpf_tcp_ca_check_member,
.init_member = bpf_tcp_ca_init_member,
.init = bpf_tcp_ca_init,
.name = "tcp_congestion_ops",