[mirror_ubuntu-jammy-kernel.git] / samples / bpf / tcp_bufs_kern.c

/* Copyright (c) 2017 Facebook
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * BPF program to set initial receive window to 40 packets and send
 * and receive buffers to 1.5MB. This would usually be done after
 * doing appropriate checks that indicate the hosts are far enough
 * away (i.e. large RTT).
 *
 * Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
 */

#include <uapi/linux/bpf.h>
#include <uapi/linux/if_ether.h>
#include <uapi/linux/if_packet.h>
#include <uapi/linux/ip.h>
#include <linux/socket.h>
#include "bpf_helpers.h"
#include "bpf_endian.h"

#define DEBUG 1

#define bpf_printk(fmt, ...)					\
({								\
	       char ____fmt[] = fmt;				\
	       bpf_trace_printk(____fmt, sizeof(____fmt),	\
				##__VA_ARGS__);			\
})

SEC("sockops")
int bpf_bufs(struct bpf_sock_ops *skops)
{
	int bufsize = 1500000;
	int rwnd_init = 40;
	int rv = 0;
	int op;

	/* For testing purposes, only execute rest of BPF program
	 * if neither port numberis 55601
	 */
	if (bpf_ntohl(skops->remote_port) != 55601 &&
	    skops->local_port != 55601) {
		skops->reply = -1;
		return 1;
	}

	op = (int) skops->op;

#ifdef DEBUG
	bpf_printk("Returning %d\n", rv);
#endif

	/* Usually there would be a check to insure the hosts are far
	 * from each other so it makes sense to increase buffer sizes
	 */
	switch (op) {
	case BPF_SOCK_OPS_RWND_INIT:
		rv = rwnd_init;
		break;
	case BPF_SOCK_OPS_TCP_CONNECT_CB:
		/* Set sndbuf and rcvbuf of active connections */
		rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
				    sizeof(bufsize));
		rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
				     &bufsize, sizeof(bufsize));
		break;
	case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
		/* Nothing to do */
		break;
	case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
		/* Set sndbuf and rcvbuf of passive connections */
		rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
				    sizeof(bufsize));
		rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
				     &bufsize, sizeof(bufsize));
		break;
	default:
		rv = -1;
	}
#ifdef DEBUG
	bpf_printk("Returning %d\n", rv);
#endif
	skops->reply = rv;
	return 1;
}
char _license[] SEC("license") = "GPL";
Commit	Line	Data
d9925368 LB	1	/* Copyright (c) 2017 Facebook
	2	*
	3	* This program is free software; you can redistribute it and/or
	4	* modify it under the terms of version 2 of the GNU General Public
	5	* License as published by the Free Software Foundation.
	6	*
	7	* BPF program to set initial receive window to 40 packets and send
	8	* and receive buffers to 1.5MB. This would usually be done after
	9	* doing appropriate checks that indicate the hosts are far enough
	10	* away (i.e. large RTT).
	11	*
ea9b6362	12	* Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
d9925368 LB	13	*/
	14
	15	#include <uapi/linux/bpf.h>
	16	#include <uapi/linux/if_ether.h>
	17	#include <uapi/linux/if_packet.h>
	18	#include <uapi/linux/ip.h>
	19	#include <linux/socket.h>
	20	#include "bpf_helpers.h"
	21	#include "bpf_endian.h"
	22
	23	#define DEBUG 1
	24
	25	#define bpf_printk(fmt, ...) \
	26	({ \
	27	char ____fmt[] = fmt; \
	28	bpf_trace_printk(____fmt, sizeof(____fmt), \
	29	##__VA_ARGS__); \
	30	})
	31
	32	SEC("sockops")
	33	int bpf_bufs(struct bpf_sock_ops *skops)
	34	{
	35	int bufsize = 1500000;
	36	int rwnd_init = 40;
	37	int rv = 0;
	38	int op;
	39
	40	/* For testing purposes, only execute rest of BPF program
	41	* if neither port numberis 55601
	42	*/
	43	if (bpf_ntohl(skops->remote_port) != 55601 &&
a4174f05 LB	44	skops->local_port != 55601) {
	45	skops->reply = -1;
	46	return 1;
	47	}
d9925368 LB	48
	49	op = (int) skops->op;
	50
	51	#ifdef DEBUG
	52	bpf_printk("Returning %d\n", rv);
	53	#endif
	54
	55	/* Usually there would be a check to insure the hosts are far
	56	* from each other so it makes sense to increase buffer sizes
	57	*/
	58	switch (op) {
	59	case BPF_SOCK_OPS_RWND_INIT:
	60	rv = rwnd_init;
	61	break;
	62	case BPF_SOCK_OPS_TCP_CONNECT_CB:
	63	/* Set sndbuf and rcvbuf of active connections */
	64	rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
	65	sizeof(bufsize));
a4174f05 LB	66	rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
a4174f05 LB	67	&bufsize, sizeof(bufsize));
d9925368 LB	68	break;
	69	case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
	70	/* Nothing to do */
	71	break;
	72	case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
	73	/* Set sndbuf and rcvbuf of passive connections */
	74	rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
	75	sizeof(bufsize));
a4174f05 LB	76	rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
a4174f05 LB	77	&bufsize, sizeof(bufsize));
d9925368 LB	78	break;
	79	default:
	80	rv = -1;
	81	}
	82	#ifdef DEBUG
	83	bpf_printk("Returning %d\n", rv);
	84	#endif
	85	skops->reply = rv;
	86	return 1;
	87	}
	88	char _license[] SEC("license") = "GPL";