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Commit 85a51f8c authored by Lorenz Bauer's avatar Lorenz Bauer Committed by Alexei Starovoitov
Browse files

bpf: allow helpers to return PTR_TO_SOCK_COMMON 



It's currently not possible to access timewait or request sockets
from eBPF, since there is no way to return a PTR_TO_SOCK_COMMON
from a helper. Introduce RET_PTR_TO_SOCK_COMMON to enable this
behaviour.

Signed-off-by: default avatarLorenz Bauer <lmb@cloudflare.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 0f3adc28

include/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -205,6 +205,7 @@ enum bpf_return_type { 
	RET_PTR_TO_MAP_VALUE_OR_NULL,	/* returns a pointer to map elem value or NULL */

	RET_PTR_TO_SOCKET_OR_NULL,	/* returns a pointer to a socket or NULL */

	RET_PTR_TO_TCP_SOCK_OR_NULL,	/* returns a pointer to a tcp_sock or NULL */

	RET_PTR_TO_SOCK_COMMON_OR_NULL,	/* returns a pointer to a sock_common or NULL */

};



/* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs

kernel/bpf/verifier.c

+4 −0
Original line number Diff line number Diff line
@@ -3148,6 +3148,10 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn 
		mark_reg_known_zero(env, regs, BPF_REG_0);

		regs[BPF_REG_0].type = PTR_TO_SOCKET_OR_NULL;

		regs[BPF_REG_0].id = ++env->id_gen;

	} else if (fn->ret_type == RET_PTR_TO_SOCK_COMMON_OR_NULL) {

		mark_reg_known_zero(env, regs, BPF_REG_0);

		regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON_OR_NULL;

		regs[BPF_REG_0].id = ++env->id_gen;

	} else if (fn->ret_type == RET_PTR_TO_TCP_SOCK_OR_NULL) {

		mark_reg_known_zero(env, regs, BPF_REG_0);

		regs[BPF_REG_0].type = PTR_TO_TCP_SOCK_OR_NULL;