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

parse_varlen.c (3487B)

      1/* Copyright (c) 2016 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#define KBUILD_MODNAME "foo"
      8#include <linux/if_ether.h>
      9#include <linux/if_vlan.h>
     10#include <linux/ip.h>
     11#include <linux/ipv6.h>
     12#include <linux/in.h>
     13#include <linux/tcp.h>
     14#include <linux/udp.h>
     15#include <uapi/linux/bpf.h>
     16#include <net/ip.h>
     17#include <bpf/bpf_helpers.h>
     18
     19#define DEFAULT_PKTGEN_UDP_PORT 9
     20#define DEBUG 0
     21
     22static int tcp(void *data, uint64_t tp_off, void *data_end)
     23{
     24	struct tcphdr *tcp = data + tp_off;
     25
     26	if (tcp + 1 > data_end)
     27		return 0;
     28	if (tcp->dest == htons(80) || tcp->source == htons(80))
     29		return TC_ACT_SHOT;
     30	return 0;
     31}
     32
     33static int udp(void *data, uint64_t tp_off, void *data_end)
     34{
     35	struct udphdr *udp = data + tp_off;
     36
     37	if (udp + 1 > data_end)
     38		return 0;
     39	if (udp->dest == htons(DEFAULT_PKTGEN_UDP_PORT) ||
     40	    udp->source == htons(DEFAULT_PKTGEN_UDP_PORT)) {
     41		if (DEBUG) {
     42			char fmt[] = "udp port 9 indeed\n";
     43
     44			bpf_trace_printk(fmt, sizeof(fmt));
     45		}
     46		return TC_ACT_SHOT;
     47	}
     48	return 0;
     49}
     50
     51static int parse_ipv4(void *data, uint64_t nh_off, void *data_end)
     52{
     53	struct iphdr *iph;
     54	uint64_t ihl_len;
     55
     56	iph = data + nh_off;
     57	if (iph + 1 > data_end)
     58		return 0;
     59
     60	if (ip_is_fragment(iph))
     61		return 0;
     62	ihl_len = iph->ihl * 4;
     63
     64	if (iph->protocol == IPPROTO_IPIP) {
     65		iph = data + nh_off + ihl_len;
     66		if (iph + 1 > data_end)
     67			return 0;
     68		ihl_len += iph->ihl * 4;
     69	}
     70
     71	if (iph->protocol == IPPROTO_TCP)
     72		return tcp(data, nh_off + ihl_len, data_end);
     73	else if (iph->protocol == IPPROTO_UDP)
     74		return udp(data, nh_off + ihl_len, data_end);
     75	return 0;
     76}
     77
     78static int parse_ipv6(void *data, uint64_t nh_off, void *data_end)
     79{
     80	struct ipv6hdr *ip6h;
     81	struct iphdr *iph;
     82	uint64_t ihl_len = sizeof(struct ipv6hdr);
     83	uint64_t nexthdr;
     84
     85	ip6h = data + nh_off;
     86	if (ip6h + 1 > data_end)
     87		return 0;
     88
     89	nexthdr = ip6h->nexthdr;
     90
     91	if (nexthdr == IPPROTO_IPIP) {
     92		iph = data + nh_off + ihl_len;
     93		if (iph + 1 > data_end)
     94			return 0;
     95		ihl_len += iph->ihl * 4;
     96		nexthdr = iph->protocol;
     97	} else if (nexthdr == IPPROTO_IPV6) {
     98		ip6h = data + nh_off + ihl_len;
     99		if (ip6h + 1 > data_end)
    100			return 0;
    101		ihl_len += sizeof(struct ipv6hdr);
    102		nexthdr = ip6h->nexthdr;
    103	}
    104
    105	if (nexthdr == IPPROTO_TCP)
    106		return tcp(data, nh_off + ihl_len, data_end);
    107	else if (nexthdr == IPPROTO_UDP)
    108		return udp(data, nh_off + ihl_len, data_end);
    109	return 0;
    110}
    111
    112SEC("varlen")
    113int handle_ingress(struct __sk_buff *skb)
    114{
    115	void *data = (void *)(long)skb->data;
    116	struct ethhdr *eth = data;
    117	void *data_end = (void *)(long)skb->data_end;
    118	uint64_t h_proto, nh_off;
    119
    120	nh_off = sizeof(*eth);
    121	if (data + nh_off > data_end)
    122		return 0;
    123
    124	h_proto = eth->h_proto;
    125
    126	if (h_proto == ETH_P_8021Q || h_proto == ETH_P_8021AD) {
    127		struct vlan_hdr *vhdr;
    128
    129		vhdr = data + nh_off;
    130		nh_off += sizeof(struct vlan_hdr);
    131		if (data + nh_off > data_end)
    132			return 0;
    133		h_proto = vhdr->h_vlan_encapsulated_proto;
    134	}
    135	if (h_proto == ETH_P_8021Q || h_proto == ETH_P_8021AD) {
    136		struct vlan_hdr *vhdr;
    137
    138		vhdr = data + nh_off;
    139		nh_off += sizeof(struct vlan_hdr);
    140		if (data + nh_off > data_end)
    141			return 0;
    142		h_proto = vhdr->h_vlan_encapsulated_proto;
    143	}
    144	if (h_proto == htons(ETH_P_IP))
    145		return parse_ipv4(data, nh_off, data_end);
    146	else if (h_proto == htons(ETH_P_IPV6))
    147		return parse_ipv6(data, nh_off, data_end);
    148	return 0;
    149}
    150char _license[] SEC("license") = "GPL";