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Commit de525be2 authored by Lawrence Brakmo's avatar Lawrence Brakmo Committed by Alexei Starovoitov
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bpf: Support passing args to sock_ops bpf function 



Adds support for passing up to 4 arguments to sock_ops bpf functions. It
reusues the reply union, so the bpf_sock_ops structures are not
increased in size.

Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent b73042b8

include/linux/filter.h

+1 −0
Original line number Diff line number Diff line
@@ -1003,6 +1003,7 @@ struct bpf_sock_ops_kern { 
	struct	sock *sk;

	u32	op;

	union {

		u32 args[4];

		u32 reply;

		u32 replylong[4];

	};

include/net/tcp.h

+35 −5
Original line number Diff line number Diff line
@@ -2006,7 +2006,7 @@ void tcp_cleanup_ulp(struct sock *sk); 
 * program loaded).

 */

#ifdef CONFIG_BPF

static inline int tcp_call_bpf(struct sock *sk, int op)

static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args)

{

	struct bpf_sock_ops_kern sock_ops;

	int ret;
@@ -2019,6 +2019,8 @@ static inline int tcp_call_bpf(struct sock *sk, int op) 


	sock_ops.sk = sk;

	sock_ops.op = op;

	if (nargs > 0)

		memcpy(sock_ops.args, args, nargs * sizeof(*args));



	ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops);

	if (ret == 0)
@@ -2027,18 +2029,46 @@ static inline int tcp_call_bpf(struct sock *sk, int op) 
		ret = -1;

	return ret;

}



static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2)

{

	u32 args[2] = {arg1, arg2};



	return tcp_call_bpf(sk, op, 2, args);

}



static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2,

				    u32 arg3)

{

	u32 args[3] = {arg1, arg2, arg3};



	return tcp_call_bpf(sk, op, 3, args);

}



#else

static inline int tcp_call_bpf(struct sock *sk, int op)

static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args)

{

	return -EPERM;

}



static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2)

{

	return -EPERM;

}



static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2,

				    u32 arg3)

{

	return -EPERM;

}



#endif



static inline u32 tcp_timeout_init(struct sock *sk)

{

	int timeout;



	timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT);

	timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL);



	if (timeout <= 0)

		timeout = TCP_TIMEOUT_INIT;
@@ -2049,7 +2079,7 @@ static inline u32 tcp_rwnd_init_bpf(struct sock *sk) 
{

	int rwnd;



	rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT);

	rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL);



	if (rwnd < 0)

		rwnd = 0;
@@ -2058,7 +2088,7 @@ static inline u32 tcp_rwnd_init_bpf(struct sock *sk) 


static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk)

{

	return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN) == 1);

	return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1);

}



#if IS_ENABLED(CONFIG_SMC)

include/uapi/linux/bpf.h

+3 −2
Original line number Diff line number Diff line
@@ -952,8 +952,9 @@ struct bpf_map_info { 
struct bpf_sock_ops {

	__u32 op;

	union {

		__u32 reply;

		__u32 replylong[4];

		__u32 args[4];		/* Optionally passed to bpf program */

		__u32 reply;		/* Returned by bpf program	    */

		__u32 replylong[4];	/* Optionally returned by bpf prog  */

	};

	__u32 family;

	__u32 remote_ip4;	/* Stored in network byte order */

net/ipv4/tcp.c

+1 −1
Original line number Diff line number Diff line
@@ -463,7 +463,7 @@ void tcp_init_transfer(struct sock *sk, int bpf_op) 
	tcp_mtup_init(sk);

	icsk->icsk_af_ops->rebuild_header(sk);

	tcp_init_metrics(sk);

	tcp_call_bpf(sk, bpf_op);

	tcp_call_bpf(sk, bpf_op, 0, NULL);

	tcp_init_congestion_control(sk);

	tcp_init_buffer_space(sk);

}

net/ipv4/tcp_nv.c

+1 −1
Original line number Diff line number Diff line
@@ -146,7 +146,7 @@ static void tcpnv_init(struct sock *sk) 
	 * within a datacenter, where we have reasonable estimates of

	 * RTTs

	 */

	base_rtt = tcp_call_bpf(sk, BPF_SOCK_OPS_BASE_RTT);

	base_rtt = tcp_call_bpf(sk, BPF_SOCK_OPS_BASE_RTT, 0, NULL);

	if (base_rtt > 0) {

		ca->nv_base_rtt = base_rtt;

		ca->nv_lower_bound_rtt = (base_rtt * 205) >> 8; /* 80% */