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_tos_reflect_kern.c (1833B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Copyright (c) 2018 Facebook
      4 *
      5 * BPF program to automatically reflect TOS option from received syn packet
      6 *
      7 * Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
      8 */
      9
     10#include <uapi/linux/bpf.h>
     11#include <uapi/linux/tcp.h>
     12#include <uapi/linux/if_ether.h>
     13#include <uapi/linux/if_packet.h>
     14#include <uapi/linux/ip.h>
     15#include <uapi/linux/ipv6.h>
     16#include <uapi/linux/in.h>
     17#include <linux/socket.h>
     18#include <bpf/bpf_helpers.h>
     19#include <bpf/bpf_endian.h>
     20
     21#define DEBUG 1
     22
     23SEC("sockops")
     24int bpf_basertt(struct bpf_sock_ops *skops)
     25{
     26	char header[sizeof(struct ipv6hdr)];
     27	struct ipv6hdr *hdr6;
     28	struct iphdr *hdr;
     29	int hdr_size = 0;
     30	int save_syn = 1;
     31	int tos = 0;
     32	int rv = 0;
     33	int op;
     34
     35	op = (int) skops->op;
     36
     37#ifdef DEBUG
     38	bpf_printk("BPF command: %d\n", op);
     39#endif
     40	switch (op) {
     41	case BPF_SOCK_OPS_TCP_LISTEN_CB:
     42		rv = bpf_setsockopt(skops, SOL_TCP, TCP_SAVE_SYN,
     43				   &save_syn, sizeof(save_syn));
     44		break;
     45	case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
     46		if (skops->family == AF_INET)
     47			hdr_size = sizeof(struct iphdr);
     48		else
     49			hdr_size = sizeof(struct ipv6hdr);
     50		rv = bpf_getsockopt(skops, SOL_TCP, TCP_SAVED_SYN,
     51				    header, hdr_size);
     52		if (!rv) {
     53			if (skops->family == AF_INET) {
     54				hdr = (struct iphdr *) header;
     55				tos = hdr->tos;
     56				if (tos != 0)
     57					bpf_setsockopt(skops, SOL_IP, IP_TOS,
     58						       &tos, sizeof(tos));
     59			} else {
     60				hdr6 = (struct ipv6hdr *) header;
     61				tos = ((hdr6->priority) << 4 |
     62				       (hdr6->flow_lbl[0]) >>  4);
     63				if (tos)
     64					bpf_setsockopt(skops, SOL_IPV6,
     65						       IPV6_TCLASS,
     66						       &tos, sizeof(tos));
     67			}
     68			rv = 0;
     69		}
     70		break;
     71	default:
     72		rv = -1;
     73	}
     74#ifdef DEBUG
     75	bpf_printk("Returning %d\n", rv);
     76#endif
     77	skops->reply = rv;
     78	return 1;
     79}
     80char _license[] SEC("license") = "GPL";