| // SPDX-License-Identifier: GPL-2.0 |
| /* Copyright (c) 2019 Facebook */ |
| |
| #include <linux/init.h> |
| #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. */ |
| static struct bpf_struct_ops bpf_tcp_congestion_ops; |
| |
| 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 const struct btf_type *tcp_congestion_ops_type; |
| |
| 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); |
| |
| type_id = btf_find_by_name_kind(btf, "tcp_congestion_ops", BTF_KIND_STRUCT); |
| if (type_id < 0) |
| return -EINVAL; |
| tcp_congestion_ops_type = btf_type_by_id(btf, type_id); |
| |
| return 0; |
| } |
| |
| 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; |
| } |
| |
| 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 (!bpf_tracing_btf_ctx_access(off, size, type, prog, info)) |
| return false; |
| |
| if (base_type(info->reg_type) == PTR_TO_BTF_ID && |
| !bpf_type_has_unsafe_modifiers(info->reg_type) && |
| 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 bpf_reg_state *reg, |
| int off, int size) |
| { |
| const struct btf_type *t; |
| size_t end; |
| |
| t = btf_type_by_id(reg->btf, reg->btf_id); |
| if (t != tcp_sock_type) { |
| bpf_log(log, "only read is supported\n"); |
| return -EACCES; |
| } |
| |
| switch (off) { |
| case offsetof(struct sock, sk_pacing_rate): |
| end = offsetofend(struct sock, sk_pacing_rate); |
| break; |
| case offsetof(struct sock, sk_pacing_status): |
| end = offsetofend(struct sock, sk_pacing_status); |
| break; |
| case bpf_ctx_range(struct inet_connection_sock, icsk_ca_priv): |
| end = offsetofend(struct inet_connection_sock, icsk_ca_priv); |
| break; |
| case offsetof(struct inet_connection_sock, icsk_ack.pending): |
| end = offsetofend(struct inet_connection_sock, |
| icsk_ack.pending); |
| break; |
| case offsetof(struct tcp_sock, snd_cwnd): |
| end = offsetofend(struct tcp_sock, snd_cwnd); |
| break; |
| case offsetof(struct tcp_sock, snd_cwnd_cnt): |
| end = offsetofend(struct tcp_sock, snd_cwnd_cnt); |
| break; |
| case offsetof(struct tcp_sock, snd_ssthresh): |
| end = offsetofend(struct tcp_sock, snd_ssthresh); |
| break; |
| case offsetof(struct tcp_sock, ecn_flags): |
| end = offsetofend(struct tcp_sock, ecn_flags); |
| break; |
| case offsetof(struct tcp_sock, app_limited): |
| end = offsetofend(struct tcp_sock, app_limited); |
| break; |
| default: |
| bpf_log(log, "no write support to tcp_sock at off %d\n", off); |
| return -EACCES; |
| } |
| |
| if (off + size > end) { |
| bpf_log(log, |
| "write access at off %d with size %d beyond the member of tcp_sock ended at %zu\n", |
| off, size, end); |
| return -EACCES; |
| } |
| |
| return 0; |
| } |
| |
| 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 = 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; |
| case BPF_FUNC_ktime_get_coarse_ns: |
| return &bpf_ktime_get_coarse_ns_proto; |
| default: |
| return bpf_base_func_proto(func_id, prog); |
| } |
| } |
| |
| BTF_KFUNCS_START(bpf_tcp_ca_check_kfunc_ids) |
| BTF_ID_FLAGS(func, tcp_reno_ssthresh) |
| BTF_ID_FLAGS(func, tcp_reno_cong_avoid) |
| BTF_ID_FLAGS(func, tcp_reno_undo_cwnd) |
| BTF_ID_FLAGS(func, tcp_slow_start) |
| BTF_ID_FLAGS(func, tcp_cong_avoid_ai) |
| BTF_KFUNCS_END(bpf_tcp_ca_check_kfunc_ids) |
| |
| static const struct btf_kfunc_id_set bpf_tcp_ca_kfunc_set = { |
| .owner = THIS_MODULE, |
| .set = &bpf_tcp_ca_check_kfunc_ids, |
| }; |
| |
| 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, |
| }; |
| |
| 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; |
| 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; |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| static int bpf_tcp_ca_check_member(const struct btf_type *t, |
| const struct btf_member *member, |
| const struct bpf_prog *prog) |
| { |
| 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) |
| { |
| tcp_unregister_congestion_control(kdata); |
| } |
| |
| static int bpf_tcp_ca_update(void *kdata, void *old_kdata) |
| { |
| return tcp_update_congestion_control(kdata, old_kdata); |
| } |
| |
| static int bpf_tcp_ca_validate(void *kdata) |
| { |
| return tcp_validate_congestion_control(kdata); |
| } |
| |
| static u32 bpf_tcp_ca_ssthresh(struct sock *sk) |
| { |
| return 0; |
| } |
| |
| static void bpf_tcp_ca_cong_avoid(struct sock *sk, u32 ack, u32 acked) |
| { |
| } |
| |
| static void bpf_tcp_ca_set_state(struct sock *sk, u8 new_state) |
| { |
| } |
| |
| static void bpf_tcp_ca_cwnd_event(struct sock *sk, enum tcp_ca_event ev) |
| { |
| } |
| |
| static void bpf_tcp_ca_in_ack_event(struct sock *sk, u32 flags) |
| { |
| } |
| |
| static void bpf_tcp_ca_pkts_acked(struct sock *sk, const struct ack_sample *sample) |
| { |
| } |
| |
| static u32 bpf_tcp_ca_min_tso_segs(struct sock *sk) |
| { |
| return 0; |
| } |
| |
| static void bpf_tcp_ca_cong_control(struct sock *sk, const struct rate_sample *rs) |
| { |
| } |
| |
| static u32 bpf_tcp_ca_undo_cwnd(struct sock *sk) |
| { |
| return 0; |
| } |
| |
| static u32 bpf_tcp_ca_sndbuf_expand(struct sock *sk) |
| { |
| return 0; |
| } |
| |
| static void __bpf_tcp_ca_init(struct sock *sk) |
| { |
| } |
| |
| static void __bpf_tcp_ca_release(struct sock *sk) |
| { |
| } |
| |
| static struct tcp_congestion_ops __bpf_ops_tcp_congestion_ops = { |
| .ssthresh = bpf_tcp_ca_ssthresh, |
| .cong_avoid = bpf_tcp_ca_cong_avoid, |
| .set_state = bpf_tcp_ca_set_state, |
| .cwnd_event = bpf_tcp_ca_cwnd_event, |
| .in_ack_event = bpf_tcp_ca_in_ack_event, |
| .pkts_acked = bpf_tcp_ca_pkts_acked, |
| .min_tso_segs = bpf_tcp_ca_min_tso_segs, |
| .cong_control = bpf_tcp_ca_cong_control, |
| .undo_cwnd = bpf_tcp_ca_undo_cwnd, |
| .sndbuf_expand = bpf_tcp_ca_sndbuf_expand, |
| |
| .init = __bpf_tcp_ca_init, |
| .release = __bpf_tcp_ca_release, |
| }; |
| |
| static 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, |
| .update = bpf_tcp_ca_update, |
| .check_member = bpf_tcp_ca_check_member, |
| .init_member = bpf_tcp_ca_init_member, |
| .init = bpf_tcp_ca_init, |
| .validate = bpf_tcp_ca_validate, |
| .name = "tcp_congestion_ops", |
| .cfi_stubs = &__bpf_ops_tcp_congestion_ops, |
| .owner = THIS_MODULE, |
| }; |
| |
| static int __init bpf_tcp_ca_kfunc_init(void) |
| { |
| int ret; |
| |
| ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &bpf_tcp_ca_kfunc_set); |
| ret = ret ?: register_bpf_struct_ops(&bpf_tcp_congestion_ops, tcp_congestion_ops); |
| |
| return ret; |
| } |
| late_initcall(bpf_tcp_ca_kfunc_init); |