diff options
Diffstat (limited to '')
| -rw-r--r-- | samples/bpf/tcp_iw_kern.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/samples/bpf/tcp_iw_kern.c b/samples/bpf/tcp_iw_kern.c new file mode 100644 index 000000000..d14445573 --- /dev/null +++ b/samples/bpf/tcp_iw_kern.c @@ -0,0 +1,83 @@ +/* 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. + * + * BPF program to set initial congestion window and initial receive + * window to 40 packets and send and receive buffers to 1.5MB. This + * would usually be done after doing appropriate checks that indicate + * the hosts are far enough away (i.e. large RTT). + * + * Use "bpftool cgroup attach $cg sock_ops $prog" 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/bpf_helpers.h> +#include <bpf/bpf_endian.h> + +#define DEBUG 1 + +SEC("sockops") +int bpf_iw(struct bpf_sock_ops *skops) +{ + int bufsize = 1500000; + int rwnd_init = 40; + int iw = 40; + 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 1; + } + + op = (int) skops->op; + +#ifdef DEBUG + bpf_printk("BPF command: %d\n", op); +#endif + + /* Usually there would be a check to insure the hosts are far + * from each other so it makes sense to increase buffer sizes + */ + switch (op) { + case BPF_SOCK_OPS_RWND_INIT: + rv = rwnd_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_IW, &iw, + sizeof(iw)); + break; + case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: + /* Set sndbuf and rcvbuf of passive connections */ + 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; + } +#ifdef DEBUG + bpf_printk("Returning %d\n", rv); +#endif + skops->reply = rv; + return 1; +} +char _license[] SEC("license") = "GPL"; |