| Lawrence Brakmo | 7bc62e2 | 2017-06-30 20:02:52 -0700 | [diff] [blame] | 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 && |
| 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 | } |
| 88 | char _license[] SEC("license") = "GPL"; |