cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

tcp_bufs_kern.c (2170B)

      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 *
     12 * Use "bpftool cgroup attach $cg sock_ops $prog" 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/bpf_helpers.h>
     21#include <bpf/bpf_endian.h>
     22
     23#define DEBUG 1
     24
     25SEC("sockops")
     26int 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 &&
     37	    skops->local_port != 55601) {
     38		skops->reply = -1;
     39		return 1;
     40	}
     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));
     59		rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
     60				     &bufsize, sizeof(bufsize));
     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));
     69		rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
     70				     &bufsize, sizeof(bufsize));
     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}
     81char _license[] SEC("license") = "GPL";