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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 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> | |
7cf245a3 THJ |
20 | #include <bpf/bpf_helpers.h> |
21 | #include <bpf/bpf_endian.h> | |
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22 | |
23 | #define DEBUG 1 | |
24 | ||
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25 | SEC("sockops") |
26 | int bpf_bufs(struct bpf_sock_ops *skops) | |
27 | { | |
28 | int bufsize = 1500000; | |
29 | int rwnd_init = 40; | |
30 | int rv = 0; | |
31 | int op; | |
32 | ||
33 | /* For testing purposes, only execute rest of BPF program | |
34 | * if neither port numberis 55601 | |
35 | */ | |
36 | if (bpf_ntohl(skops->remote_port) != 55601 && | |
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37 | skops->local_port != 55601) { |
38 | skops->reply = -1; | |
39 | return 1; | |
40 | } | |
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41 | |
42 | op = (int) skops->op; | |
43 | ||
44 | #ifdef DEBUG | |
45 | bpf_printk("Returning %d\n", rv); | |
46 | #endif | |
47 | ||
48 | /* Usually there would be a check to insure the hosts are far | |
49 | * from each other so it makes sense to increase buffer sizes | |
50 | */ | |
51 | switch (op) { | |
52 | case BPF_SOCK_OPS_RWND_INIT: | |
53 | rv = rwnd_init; | |
54 | break; | |
55 | case BPF_SOCK_OPS_TCP_CONNECT_CB: | |
56 | /* Set sndbuf and rcvbuf of active connections */ | |
57 | rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize, | |
58 | sizeof(bufsize)); | |
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59 | rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF, |
60 | &bufsize, sizeof(bufsize)); | |
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61 | break; |
62 | case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB: | |
63 | /* Nothing to do */ | |
64 | break; | |
65 | case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: | |
66 | /* Set sndbuf and rcvbuf of passive connections */ | |
67 | rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize, | |
68 | sizeof(bufsize)); | |
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69 | rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF, |
70 | &bufsize, sizeof(bufsize)); | |
d9925368 LB |
71 | break; |
72 | default: | |
73 | rv = -1; | |
74 | } | |
75 | #ifdef DEBUG | |
76 | bpf_printk("Returning %d\n", rv); | |
77 | #endif | |
78 | skops->reply = rv; | |
79 | return 1; | |
80 | } | |
81 | char _license[] SEC("license") = "GPL"; |