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/* Copyright (C) 2018 Open Information Security Foundation
*
* You can copy, redistribute or modify this Program under the terms of
* the GNU General Public License version 2 as published by the Free
* Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
#include <stddef.h>
#include <linux/bpf.h>
#include <linux/if_ether.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/in6.h>
#include <linux/ipv6.h>
#include <linux/filter.h>
#include "bpf_helpers.h"
#define LINUX_VERSION_CODE 263682
#ifndef __section
# define __section(x) __attribute__((section(x), used))
#endif
struct vlan_hdr {
__u16 h_vlan_TCI;
__u16 h_vlan_encapsulated_proto;
};
static __always_inline int ipv4_hash(struct __sk_buff *skb)
{
__u32 nhoff;
__u32 src, dst;
nhoff = skb->cb[0];
src = load_word(skb, nhoff + offsetof(struct iphdr, saddr));
dst = load_word(skb, nhoff + offsetof(struct iphdr, daddr));
#if 0
char fmt[] = "Got addr: %x -> %x at %d\n";
bpf_trace_printk(fmt, sizeof(fmt), src, dst, nhoff);
//char fmt2[] = "Got hash %u\n";
//bpf_trace_printk(fmt2, sizeof(fmt2), src + dst);
#endif
return src + dst;
}
static inline __u32 ipv6_addr_hash(struct __sk_buff *ctx, __u64 off)
{
__u64 w0 = load_word(ctx, off);
__u64 w1 = load_word(ctx, off + 4);
__u64 w2 = load_word(ctx, off + 8);
__u64 w3 = load_word(ctx, off + 12);
return (__u32)(w0 ^ w1 ^ w2 ^ w3);
}
static __always_inline int ipv6_hash(struct __sk_buff *skb)
{
__u32 nhoff;
__u32 src_hash, dst_hash;
nhoff = skb->cb[0];
src_hash = ipv6_addr_hash(skb,
nhoff + offsetof(struct ipv6hdr, saddr));
dst_hash = ipv6_addr_hash(skb,
nhoff + offsetof(struct ipv6hdr, daddr));
return src_hash + dst_hash;
}
int __section("loadbalancer") lb(struct __sk_buff *skb) {
__u64 nhoff = ETH_HLEN;
__u16 proto = load_half(skb, ETH_HLEN - ETH_TLEN);
__u16 ret = proto;
switch (proto) {
case ETH_P_8021Q:
case ETH_P_8021AD:
{
__u16 vproto = load_half(skb, nhoff + offsetof(struct vlan_hdr, h_vlan_encapsulated_proto));
switch(vproto) {
case ETH_P_8021AD:
case ETH_P_8021Q:
nhoff += sizeof(struct vlan_hdr);
proto = load_half(skb, nhoff + offsetof(struct vlan_hdr, h_vlan_encapsulated_proto));
break;
default:
proto = vproto;
}
nhoff += sizeof(struct vlan_hdr);
skb->cb[0] = nhoff;
switch (proto) {
case ETH_P_IP:
#if 0
{ char fmt[] = "ipv4\n"; bpf_trace_printk(fmt, sizeof(fmt));}
#endif
ret = ipv4_hash(skb);
break;
case ETH_P_IPV6:
ret = ipv6_hash(skb);
break;
default:
#if 0
{
char fmt[] = "Dflt VLAN proto %u\n";
bpf_trace_printk(fmt, sizeof(fmt), proto);
break;
}
#else
break;
#endif
}
}
break;
case ETH_P_IP:
ret = ipv4_hash(skb);
break;
case ETH_P_IPV6:
ret = ipv6_hash(skb);
break;
default:
#if 0
{
char fmt[] = "Got proto %x\n";
bpf_trace_printk(fmt, sizeof(fmt), proto);
break;
}
#else
break;
#endif
}
return ret;
}
char __license[] __section("license") = "GPL";
/* libbpf needs version section to check sync of eBPF code and kernel
* but socket filter don't need it */
__u32 __version __section("version") = LINUX_VERSION_CODE;
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