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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 | ||
32 | SEC("sockops") | |
33 | int 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 && | |
e1853319 LB |
45 | skops->local_port != 55601) { |
46 | skops->reply = -1; | |
47 | return 1; | |
48 | } | |
7bc62e28 LB |
49 | |
50 | op = (int) skops->op; | |
51 | ||
52 | #ifdef DEBUG | |
53 | bpf_printk("BPF command: %d\n", op); | |
54 | #endif | |
55 | ||
56 | /* Usually there would be a check to insure the hosts are far | |
57 | * from each other so it makes sense to increase buffer sizes | |
58 | */ | |
59 | switch (op) { | |
60 | case BPF_SOCK_OPS_RWND_INIT: | |
61 | rv = rwnd_init; | |
62 | break; | |
63 | case BPF_SOCK_OPS_TCP_CONNECT_CB: | |
64 | /* Set sndbuf and rcvbuf of active connections */ | |
65 | rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize, | |
66 | sizeof(bufsize)); | |
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67 | rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF, |
68 | &bufsize, sizeof(bufsize)); | |
7bc62e28 LB |
69 | break; |
70 | case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB: | |
71 | rv = bpf_setsockopt(skops, SOL_TCP, TCP_BPF_IW, &iw, | |
72 | sizeof(iw)); | |
73 | break; | |
74 | case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: | |
75 | /* Set sndbuf and rcvbuf of passive connections */ | |
76 | rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize, | |
77 | sizeof(bufsize)); | |
e1853319 LB |
78 | rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF, |
79 | &bufsize, sizeof(bufsize)); | |
7bc62e28 LB |
80 | break; |
81 | default: | |
82 | rv = -1; | |
83 | } | |
84 | #ifdef DEBUG | |
85 | bpf_printk("Returning %d\n", rv); | |
86 | #endif | |
87 | skops->reply = rv; | |
88 | return 1; | |
89 | } | |
90 | char _license[] SEC("license") = "GPL"; |