tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 congestion window and initial receive
8 * window to 40 packets and send and receive buffers to 1.5MB. This
9 * would usually be done after doing appropriate checks that indicate
10 * the hosts are far enough away (i.e. large RTT).
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
32SEC("sockops")
33int bpf_iw(struct bpf_sock_ops *skops)
34{
35 int bufsize = 1500000;
36 int rwnd_init = 40;
37 int iw = 40;
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 */
44 if (bpf_ntohl(skops->remote_port) != 55601 &&
45 skops->local_port != 55601)
46 return -1;
47
48 op = (int) skops->op;
49
50#ifdef DEBUG
51 bpf_printk("BPF command: %d\n", op);
52#endif
53
54 /* Usually there would be a check to insure the hosts are far
55 * from each other so it makes sense to increase buffer sizes
56 */
57 switch (op) {
58 case BPF_SOCK_OPS_RWND_INIT:
59 rv = rwnd_init;
60 break;
61 case BPF_SOCK_OPS_TCP_CONNECT_CB:
62 /* Set sndbuf and rcvbuf of active connections */
63 rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
64 sizeof(bufsize));
65 rv = rv*100 + bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
66 &bufsize, sizeof(bufsize));
67 break;
68 case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
69 rv = bpf_setsockopt(skops, SOL_TCP, TCP_BPF_IW, &iw,
70 sizeof(iw));
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));
76 rv = rv*100 + bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
77 &bufsize, sizeof(bufsize));
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}
88char _license[] SEC("license") = "GPL";