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Commit edbf8c01 authored by Lorenz Bauer's avatar Lorenz Bauer Committed by Alexei Starovoitov
Browse files

bpf: add skc_lookup_tcp helper 



Allow looking up a sock_common. This gives eBPF programs
access to timewait and request sockets.

Signed-off-by: default avatarLorenz Bauer <lmb@cloudflare.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 85a51f8c

include/uapi/linux/bpf.h

+19 −1
Original line number Diff line number Diff line
@@ -2431,6 +2431,23 @@ union bpf_attr { 
 *	Return

 *		A **struct bpf_sock** pointer on success, or **NULL** in

 *		case of failure.

 *

 * struct bpf_sock *bpf_skc_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)

 *	Description

 *		Look for TCP socket matching *tuple*, optionally in a child

 *		network namespace *netns*. The return value must be checked,

 *		and if non-**NULL**, released via **bpf_sk_release**\ ().

 *

 *		This function is identical to bpf_sk_lookup_tcp, except that it

 *		also returns timewait or request sockets. Use bpf_sk_fullsock

 *		or bpf_tcp_socket to access the full structure.

 *

 *		This helper is available only if the kernel was compiled with

 *		**CONFIG_NET** configuration option.

 *	Return

 *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.

 *		For sockets with reuseport option, the **struct bpf_sock**

 *		result is from **reuse->socks**\ [] using the hash of the tuple.

 */

#define __BPF_FUNC_MAPPER(FN)		\

	FN(unspec),			\
@@ -2531,7 +2548,8 @@ union bpf_attr { 
	FN(sk_fullsock),		\

	FN(tcp_sock),			\

	FN(skb_ecn_set_ce),		\

	FN(get_listener_sock),

	FN(get_listener_sock),		\

	FN(skc_lookup_tcp),



/* integer value in 'imm' field of BPF_CALL instruction selects which helper

 * function eBPF program intends to call

kernel/bpf/verifier.c

+2 −1
Original line number Diff line number Diff line
@@ -369,7 +369,8 @@ static bool is_release_function(enum bpf_func_id func_id) 
static bool is_acquire_function(enum bpf_func_id func_id)

{

	return func_id == BPF_FUNC_sk_lookup_tcp ||

		func_id == BPF_FUNC_sk_lookup_udp;

		func_id == BPF_FUNC_sk_lookup_udp ||

		func_id == BPF_FUNC_skc_lookup_tcp;

}



static bool is_ptr_cast_function(enum bpf_func_id func_id)

net/core/filter.c

+122 −22
Original line number Diff line number Diff line
@@ -5156,13 +5156,13 @@ static struct sock *sk_lookup(struct net *net, struct bpf_sock_tuple *tuple, 
	return sk;

}



/* bpf_sk_lookup performs the core lookup for different types of sockets,

/* bpf_skc_lookup performs the core lookup for different types of sockets,

 * taking a reference on the socket if it doesn't have the flag SOCK_RCU_FREE.

 * Returns the socket as an 'unsigned long' to simplify the casting in the

 * callers to satisfy BPF_CALL declarations.

 */

static unsigned long

__bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,

static struct sock *

__bpf_skc_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,

		 struct net *caller_net, u32 ifindex, u8 proto, u64 netns_id,

		 u64 flags)

{
@@ -5192,14 +5192,26 @@ __bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len, 
		put_net(net);

	}



out:

	return sk;

}



static struct sock *

__bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,

		struct net *caller_net, u32 ifindex, u8 proto, u64 netns_id,

		u64 flags)

{

	struct sock *sk = __bpf_skc_lookup(skb, tuple, len, caller_net,

					   ifindex, proto, netns_id, flags);



	if (sk)

		sk = sk_to_full_sk(sk);

out:

	return (unsigned long) sk;



	return sk;

}



static unsigned long

bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,

static struct sock *

bpf_skc_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,

	       u8 proto, u64 netns_id, u64 flags)

{

	struct net *caller_net;
@@ -5213,14 +5225,47 @@ bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len, 
		ifindex = 0;

	}



	return __bpf_sk_lookup(skb, tuple, len, caller_net, ifindex,

			      proto, netns_id, flags);

	return __bpf_skc_lookup(skb, tuple, len, caller_net, ifindex, proto,

				netns_id, flags);

}



static struct sock *

bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,

	      u8 proto, u64 netns_id, u64 flags)

{

	struct sock *sk = bpf_skc_lookup(skb, tuple, len, proto, netns_id,

					 flags);



	if (sk)

		sk = sk_to_full_sk(sk);



	return sk;

}



BPF_CALL_5(bpf_skc_lookup_tcp, struct sk_buff *, skb,

	   struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)

{

	return (unsigned long)bpf_skc_lookup(skb, tuple, len, IPPROTO_TCP,

					     netns_id, flags);

}



static const struct bpf_func_proto bpf_skc_lookup_tcp_proto = {

	.func		= bpf_skc_lookup_tcp,

	.gpl_only	= false,

	.pkt_access	= true,

	.ret_type	= RET_PTR_TO_SOCK_COMMON_OR_NULL,

	.arg1_type	= ARG_PTR_TO_CTX,

	.arg2_type	= ARG_PTR_TO_MEM,

	.arg3_type	= ARG_CONST_SIZE,

	.arg4_type	= ARG_ANYTHING,

	.arg5_type	= ARG_ANYTHING,

};



BPF_CALL_5(bpf_sk_lookup_tcp, struct sk_buff *, skb,

	   struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)

{

	return bpf_sk_lookup(skb, tuple, len, IPPROTO_TCP, netns_id, flags);

	return (unsigned long)bpf_sk_lookup(skb, tuple, len, IPPROTO_TCP,

					    netns_id, flags);

}



static const struct bpf_func_proto bpf_sk_lookup_tcp_proto = {
@@ -5238,7 +5283,8 @@ static const struct bpf_func_proto bpf_sk_lookup_tcp_proto = { 
BPF_CALL_5(bpf_sk_lookup_udp, struct sk_buff *, skb,

	   struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)

{

	return bpf_sk_lookup(skb, tuple, len, IPPROTO_UDP, netns_id, flags);

	return (unsigned long)bpf_sk_lookup(skb, tuple, len, IPPROTO_UDP,

					    netns_id, flags);

}



static const struct bpf_func_proto bpf_sk_lookup_udp_proto = {
@@ -5273,8 +5319,9 @@ BPF_CALL_5(bpf_xdp_sk_lookup_udp, struct xdp_buff *, ctx, 
	struct net *caller_net = dev_net(ctx->rxq->dev);

	int ifindex = ctx->rxq->dev->ifindex;



	return __bpf_sk_lookup(NULL, tuple, len, caller_net, ifindex,

			      IPPROTO_UDP, netns_id, flags);

	return (unsigned long)__bpf_sk_lookup(NULL, tuple, len, caller_net,

					      ifindex, IPPROTO_UDP, netns_id,

					      flags);

}



static const struct bpf_func_proto bpf_xdp_sk_lookup_udp_proto = {
@@ -5289,14 +5336,38 @@ static const struct bpf_func_proto bpf_xdp_sk_lookup_udp_proto = { 
	.arg5_type      = ARG_ANYTHING,

};



BPF_CALL_5(bpf_xdp_skc_lookup_tcp, struct xdp_buff *, ctx,

	   struct bpf_sock_tuple *, tuple, u32, len, u32, netns_id, u64, flags)

{

	struct net *caller_net = dev_net(ctx->rxq->dev);

	int ifindex = ctx->rxq->dev->ifindex;



	return (unsigned long)__bpf_skc_lookup(NULL, tuple, len, caller_net,

					       ifindex, IPPROTO_TCP, netns_id,

					       flags);

}



static const struct bpf_func_proto bpf_xdp_skc_lookup_tcp_proto = {

	.func           = bpf_xdp_skc_lookup_tcp,

	.gpl_only       = false,

	.pkt_access     = true,

	.ret_type       = RET_PTR_TO_SOCK_COMMON_OR_NULL,

	.arg1_type      = ARG_PTR_TO_CTX,

	.arg2_type      = ARG_PTR_TO_MEM,

	.arg3_type      = ARG_CONST_SIZE,

	.arg4_type      = ARG_ANYTHING,

	.arg5_type      = ARG_ANYTHING,

};



BPF_CALL_5(bpf_xdp_sk_lookup_tcp, struct xdp_buff *, ctx,

	   struct bpf_sock_tuple *, tuple, u32, len, u32, netns_id, u64, flags)

{

	struct net *caller_net = dev_net(ctx->rxq->dev);

	int ifindex = ctx->rxq->dev->ifindex;



	return __bpf_sk_lookup(NULL, tuple, len, caller_net, ifindex,

			      IPPROTO_TCP, netns_id, flags);

	return (unsigned long)__bpf_sk_lookup(NULL, tuple, len, caller_net,

					      ifindex, IPPROTO_TCP, netns_id,

					      flags);

}



static const struct bpf_func_proto bpf_xdp_sk_lookup_tcp_proto = {
@@ -5311,13 +5382,33 @@ static const struct bpf_func_proto bpf_xdp_sk_lookup_tcp_proto = { 
	.arg5_type      = ARG_ANYTHING,

};



BPF_CALL_5(bpf_sock_addr_sk_lookup_tcp, struct bpf_sock_addr_kern *, ctx,

BPF_CALL_5(bpf_sock_addr_skc_lookup_tcp, struct bpf_sock_addr_kern *, ctx,

	   struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)

{

	return __bpf_sk_lookup(NULL, tuple, len, sock_net(ctx->sk), 0,

	return (unsigned long)__bpf_skc_lookup(NULL, tuple, len,

					       sock_net(ctx->sk), 0,

					       IPPROTO_TCP, netns_id, flags);

}



static const struct bpf_func_proto bpf_sock_addr_skc_lookup_tcp_proto = {

	.func		= bpf_sock_addr_skc_lookup_tcp,

	.gpl_only	= false,

	.ret_type	= RET_PTR_TO_SOCK_COMMON_OR_NULL,

	.arg1_type	= ARG_PTR_TO_CTX,

	.arg2_type	= ARG_PTR_TO_MEM,

	.arg3_type	= ARG_CONST_SIZE,

	.arg4_type	= ARG_ANYTHING,

	.arg5_type	= ARG_ANYTHING,

};



BPF_CALL_5(bpf_sock_addr_sk_lookup_tcp, struct bpf_sock_addr_kern *, ctx,

	   struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)

{

	return (unsigned long)__bpf_sk_lookup(NULL, tuple, len,

					      sock_net(ctx->sk), 0, IPPROTO_TCP,

					      netns_id, flags);

}



static const struct bpf_func_proto bpf_sock_addr_sk_lookup_tcp_proto = {

	.func		= bpf_sock_addr_sk_lookup_tcp,

	.gpl_only	= false,
@@ -5332,8 +5423,9 @@ static const struct bpf_func_proto bpf_sock_addr_sk_lookup_tcp_proto = { 
BPF_CALL_5(bpf_sock_addr_sk_lookup_udp, struct bpf_sock_addr_kern *, ctx,

	   struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)

{

	return __bpf_sk_lookup(NULL, tuple, len, sock_net(ctx->sk), 0,

			       IPPROTO_UDP, netns_id, flags);

	return (unsigned long)__bpf_sk_lookup(NULL, tuple, len,

					      sock_net(ctx->sk), 0, IPPROTO_UDP,

					      netns_id, flags);

}



static const struct bpf_func_proto bpf_sock_addr_sk_lookup_udp_proto = {
@@ -5586,6 +5678,8 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 
		return &bpf_sock_addr_sk_lookup_udp_proto;

	case BPF_FUNC_sk_release:

		return &bpf_sk_release_proto;

	case BPF_FUNC_skc_lookup_tcp:

		return &bpf_sock_addr_skc_lookup_tcp_proto;

#endif /* CONFIG_INET */

	default:

		return bpf_base_func_proto(func_id);
@@ -5719,6 +5813,8 @@ tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 
		return &bpf_tcp_sock_proto;

	case BPF_FUNC_get_listener_sock:

		return &bpf_get_listener_sock_proto;

	case BPF_FUNC_skc_lookup_tcp:

		return &bpf_skc_lookup_tcp_proto;

#endif

	default:

		return bpf_base_func_proto(func_id);
@@ -5754,6 +5850,8 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 
		return &bpf_xdp_sk_lookup_tcp_proto;

	case BPF_FUNC_sk_release:

		return &bpf_sk_release_proto;

	case BPF_FUNC_skc_lookup_tcp:

		return &bpf_xdp_skc_lookup_tcp_proto;

#endif

	default:

		return bpf_base_func_proto(func_id);
@@ -5846,6 +5944,8 @@ sk_skb_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 
		return &bpf_sk_lookup_udp_proto;

	case BPF_FUNC_sk_release:

		return &bpf_sk_release_proto;

	case BPF_FUNC_skc_lookup_tcp:

		return &bpf_skc_lookup_tcp_proto;

#endif

	default:

		return bpf_base_func_proto(func_id);