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_iw_kern.c (2271B)

      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 "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_iw(struct bpf_sock_ops *skops)
     27{
     28	int bufsize = 1500000;
     29	int rwnd_init = 40;
     30	int iw = 40;
     31	int rv = 0;
     32	int op;
     33
     34	/* For testing purposes, only execute rest of BPF program
     35	 * if neither port numberis 55601
     36	 */
     37	if (bpf_ntohl(skops->remote_port) != 55601 &&
     38	    skops->local_port != 55601) {
     39		skops->reply = -1;
     40		return 1;
     41	}
     42
     43	op = (int) skops->op;
     44
     45#ifdef DEBUG
     46	bpf_printk("BPF command: %d\n", op);
     47#endif
     48
     49	/* Usually there would be a check to insure the hosts are far
     50	 * from each other so it makes sense to increase buffer sizes
     51	 */
     52	switch (op) {
     53	case BPF_SOCK_OPS_RWND_INIT:
     54		rv = rwnd_init;
     55		break;
     56	case BPF_SOCK_OPS_TCP_CONNECT_CB:
     57		/* Set sndbuf and rcvbuf of active connections */
     58		rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
     59				    sizeof(bufsize));
     60		rv += bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
     61				     &bufsize, sizeof(bufsize));
     62		break;
     63	case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
     64		rv = bpf_setsockopt(skops, SOL_TCP, TCP_BPF_IW, &iw,
     65				    sizeof(iw));
     66		break;
     67	case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
     68		/* Set sndbuf and rcvbuf of passive connections */
     69		rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize,
     70				    sizeof(bufsize));
     71		rv +=  bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF,
     72				      &bufsize, sizeof(bufsize));
     73		break;
     74	default:
     75		rv = -1;
     76	}
     77#ifdef DEBUG
     78	bpf_printk("Returning %d\n", rv);
     79#endif
     80	skops->reply = rv;
     81	return 1;
     82}
     83char _license[] SEC("license") = "GPL";