[linux-2.6-block.git] / samples / bpf / tcp_clamp_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.
 *
 * Sample BPF program to set send and receive buffers to 150KB, sndcwnd clamp
 * to 100 packets and SYN and SYN_ACK RTOs to 10ms when both hosts are within
 * the same datacenter. For his example, we assume they are within the same
 * datacenter when the first 5.5 bytes of their IPv6 addresses are the same.
 *
 * Use load_sock_ops 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_clamp(struct bpf_sock_ops *skops)
{
	int bufsize = 150000;
	int to_init = 10;
	int clamp = 100;
	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 0;
	}

	op = (int) skops->op;

#ifdef DEBUG
	bpf_printk("BPF command: %d\n", op);
#endif

	/* Check that both hosts are within same datacenter. For this example
	 * it is the case when the first 5.5 bytes of their IPv6 addresses are
	 * the same.
	 */
	if (skops->family == AF_INET6 &&
	    skops->local_ip6[0] == skops->remote_ip6[0] &&
	    (bpf_ntohl(skops->local_ip6[1]) & 0xfff00000) ==
	    (bpf_ntohl(skops->remote_ip6[1]) & 0xfff00000)) {
		switch (op) {
		case BPF_SOCK_OPS_TIMEOUT_INIT:
			rv = to_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:
			rv = bpf_setsockopt(skops, SOL_TCP,
					    TCP_BPF_SNDCWND_CLAMP,
					    &clamp, sizeof(clamp));
			break;
		case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
			/* Set sndbuf and rcvbuf of passive connections */
			rv = bpf_setsockopt(skops, SOL_TCP,
					    TCP_BPF_SNDCWND_CLAMP,
					    &clamp, sizeof(clamp));
			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;
		}
	} else {
		rv = -1;
	}
#ifdef DEBUG
	bpf_printk("Returning %d\n", rv);
#endif
	skops->reply = rv;
	return 1;
}
char _license[] SEC("license") = "GPL";
Commit	Line	Data
6c4a01b2 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	* Sample BPF program to set send and receive buffers to 150KB, sndcwnd clamp
	8	* to 100 packets and SYN and SYN_ACK RTOs to 10ms when both hosts are within
	9	* the same datacenter. For his example, we assume they are within the same
	10	* datacenter when the first 5.5 bytes of their IPv6 addresses are the same.
	11	*
	12	* Use load_sock_ops to load this BPF program.
	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_clamp(struct bpf_sock_ops *skops)
	34	{
	35	int bufsize = 150000;
	36	int to_init = 10;
	37	int clamp = 100;
	38	int rv = 0;
	39	int op;
	40
	41	/* For testing purposes, only execute rest of BPF program
	42	* if neither port numberis 55601
	43	*/
03e982ee LB	44	if (bpf_ntohl(skops->remote_port) != 55601 && skops->local_port != 55601) {
	45	skops->reply = -1;
	46	return 0;
	47	}
6c4a01b2 LB	48
	49	op = (int) skops->op;
	50
	51	#ifdef DEBUG
	52	bpf_printk("BPF command: %d\n", op);
	53	#endif
	54
	55	/* Check that both hosts are within same datacenter. For this example
	56	* it is the case when the first 5.5 bytes of their IPv6 addresses are
	57	* the same.
	58	*/
	59	if (skops->family == AF_INET6 &&
	60	skops->local_ip6[0] == skops->remote_ip6[0] &&
	61	(bpf_ntohl(skops->local_ip6[1]) & 0xfff00000) ==
	62	(bpf_ntohl(skops->remote_ip6[1]) & 0xfff00000)) {
	63	switch (op) {
	64	case BPF_SOCK_OPS_TIMEOUT_INIT:
	65	rv = to_init;
	66	break;
	67	case BPF_SOCK_OPS_TCP_CONNECT_CB:
	68	/* Set sndbuf and rcvbuf of active connections */
	69	rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF,
	70	&bufsize, sizeof(bufsize));
03e982ee LB	71	rv += bpf_setsockopt(skops, SOL_SOCKET,
	72	SO_RCVBUF, &bufsize,
	73	sizeof(bufsize));
6c4a01b2 LB	74	break;
	75	case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
	76	rv = bpf_setsockopt(skops, SOL_TCP,
	77	TCP_BPF_SNDCWND_CLAMP,
	78	&clamp, sizeof(clamp));
	79	break;
	80	case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
	81	/* Set sndbuf and rcvbuf of passive connections */
	82	rv = bpf_setsockopt(skops, SOL_TCP,
	83	TCP_BPF_SNDCWND_CLAMP,
	84	&clamp, sizeof(clamp));
03e982ee LB	85	rv += bpf_setsockopt(skops, SOL_SOCKET,
	86	SO_SNDBUF, &bufsize,
	87	sizeof(bufsize));
	88	rv += bpf_setsockopt(skops, SOL_SOCKET,
	89	SO_RCVBUF, &bufsize,
	90	sizeof(bufsize));
6c4a01b2 LB	91	break;
	92	default:
	93	rv = -1;
	94	}
	95	} else {
	96	rv = -1;
	97	}
	98	#ifdef DEBUG
	99	bpf_printk("Returning %d\n", rv);
	100	#endif
	101	skops->reply = rv;
	102	return 1;
	103	}
	104	char _license[] SEC("license") = "GPL";