// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2022 Meta
#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#include <linux/bpf.h>
#include <linux/stddef.h>
#include <linux/pkt_cls.h>
#include <linux/if_ether.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
/* veth_src --- veth_src_fwd --- veth_det_fwd --- veth_dst
* | |
* ns_src | ns_fwd | ns_dst
*
* ns_src and ns_dst: ENDHOST namespace
* ns_fwd: Fowarding namespace
*/
#define ctx_ptr(field) (void *)(long)(field)
#define ip4_src __bpf_htonl(0xac100164) /* 172.16.1.100 */
#define ip4_dst __bpf_htonl(0xac100264) /* 172.16.2.100 */
#define ip6_src { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
0x00, 0x01, 0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe }
#define ip6_dst { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
0x00, 0x02, 0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe }
#define v6_equal(a, b) (a.s6_addr32[0] == b.s6_addr32[0] && \
a.s6_addr32[1] == b.s6_addr32[1] && \
a.s6_addr32[2] == b.s6_addr32[2] && \
a.s6_addr32[3] == b.s6_addr32[3])
volatile const __u32 IFINDEX_SRC;
volatile const __u32 IFINDEX_DST;
#define EGRESS_ENDHOST_MAGIC 0x0b9fbeef
#define INGRESS_FWDNS_MAGIC 0x1b9fbeef
#define EGRESS_FWDNS_MAGIC 0x2b9fbeef
enum {
INGRESS_FWDNS_P100,
INGRESS_FWDNS_P101,
EGRESS_FWDNS_P100,
EGRESS_FWDNS_P101,
INGRESS_ENDHOST,
EGRESS_ENDHOST,
SET_DTIME,
__MAX_CNT,
};
enum {
TCP_IP6_CLEAR_DTIME,
TCP_IP4,
TCP_IP6,
UDP_IP4,
UDP_IP6,
TCP_IP4_RT_FWD,
TCP_IP6_RT_FWD,
UDP_IP4_RT_FWD,
UDP_IP6_RT_FWD,
UKN_TEST,
__NR_TESTS,
};
enum {
SRC_NS = 1,
DST_NS,
};
__u32 dtimes[__NR_TESTS][__MAX_CNT] = {};
__u32 errs[__NR_TESTS][__MAX_CNT] = {};
__u32 test = 0;
static void inc_dtimes(__u32 idx)
{
if (test < __NR_TESTS)
dtimes[test][idx]++;
else
dtimes[UKN_TEST][idx]++;
}
static void inc_errs(__u32 idx)
{
if (test < __NR_TESTS)
errs[test][idx]++;
else
errs[UKN_TEST][idx]++;
}
static int skb_proto(int type)
{
return type & 0xff;
}
static int skb_ns(int type)
{
return (type >> 8) & 0xff;
}
static bool fwdns_clear_dtime(void)
{
return test == TCP_IP6_CLEAR_DTIME;
}
static bool bpf_fwd(void)
{
return test < TCP_IP4_RT_FWD;
}
static __u8 get_proto(void)
{
switch (test) {
case UDP_IP4:
case UDP_IP6:
case UDP_IP4_RT_FWD:
case UDP_IP6_RT_FWD:
return IPPROTO_UDP;
default:
return IPPROTO_TCP;
}
}
/* -1: parse error: TC_ACT_SHOT
* 0: not testing traffic: TC_ACT_OK
* >0: first byte is the inet_proto, second byte has the netns
* of the sender
*/
static int skb_get_type(struct __sk_buff *skb)
{
__u16 dst_ns_port = __bpf_htons(50000 + test);
void *data_end = ctx_ptr(skb->data_end);
void *data = ctx_ptr(skb->data);
__u8 inet_proto = 0, ns = 0;
struct ipv6hdr *ip6h;
__u16 sport, dport;
struct iphdr *iph;
struct tcphdr *th;
struct udphdr *uh;
void *trans;
switch (skb->protocol) {
case __bpf_htons(ETH_P_IP):
iph = data + sizeof(struct ethhdr);
if (iph + 1 > data_end)
return -1;
if (iph->saddr == ip4_src)
ns = SRC_NS;
else if (iph->saddr == ip4_dst)
ns = DST_NS;
inet_proto = iph->protocol;
trans = iph + 1;
break;
case __bpf_htons(ETH_P_IPV6):
ip6h = data + sizeof(struct ethhdr);
if (ip6h + 1 > data_end)
return -1;
if (v6_equal(ip6h->saddr, (struct in6_addr){{ip6_src}}))
ns = SRC_NS;
else if (v6_equal(ip6h->saddr, (struct in6_addr){{ip6_dst}}))
ns = DST_NS;
inet_proto = ip6h->nexthdr;
trans = ip6h + 1;
break;
default:
return 0;
}
/* skb is not from src_ns or dst_ns.
* skb is not the testing IPPROTO.
*/
if (!ns || inet_proto != get_proto())
return 0;
switch (inet_proto) {
case IPPROTO_TCP:
th = trans;
if (th + 1 > data_end)
return -1;
sport = th->source;
dport = th->dest;
break;
case IPPROTO_UDP:
uh = trans;
if (uh + 1 > data_end)
return -1;
sport = uh->source;
dport = uh->dest;
break;
default:
return 0;
}
/* The skb is the testing traffic */
if ((ns == SRC_NS && dport == dst_ns_port) ||
(ns == DST_NS && sport == dst_ns_port))
return (ns << 8 | inet_proto);
return 0;
}
/* format: direction@iface@netns
* egress@veth_(src|dst)@ns_(src|dst)
*/
SEC("tc")
int egress_host(struct __sk_buff *skb)
{
int skb_type;
skb_type = skb_get_type(skb);
if (skb_type == -1)
return TC_ACT_SHOT;
if (!skb_type)
return TC_ACT_OK;
if (skb_proto(skb_type) == IPPROTO_TCP) {
if (skb->tstamp_type == BPF_SKB_CLOCK_MONOTONIC &&
skb->tstamp)
inc_dtimes(EGRESS_ENDHOST);
else
inc_errs(EGRESS_ENDHOST);
} else if (skb_proto(skb_type) == IPPROTO_UDP) {
if (skb->tstamp_type == BPF_SKB_CLOCK_TAI &&
skb->tstamp)
inc_dtimes(EGRESS_ENDHOST);
else
inc_errs(EGRESS_ENDHOST);
} else {
if (skb->tstamp_type == BPF_SKB_CLOCK_REALTIME &&
skb->tstamp)
inc_errs(EGRESS_ENDHOST);
}
skb->tstamp = EGRESS_ENDHOST_MAGIC;
return TC_ACT_OK;
}
/* ingress@veth_(src|dst)@ns_(src|dst) */
SEC("tc")
int ingress_host(struct __sk_buff *skb)
{
int skb_type;
skb_type = skb_get_type(skb);
if (skb_type == -1)
return TC_ACT_SHOT;
if (!skb_type)
return TC_ACT_OK;
if (skb->tstamp_type == BPF_SKB_CLOCK_MONOTONIC &&
skb->tstamp == EGRESS_FWDNS_MAGIC)
inc_dtimes(INGRESS_ENDHOST);
else
inc_errs(INGRESS_ENDHOST);
return TC_ACT_OK;
}
/* ingress@veth_(src|dst)_fwd@ns_fwd priority 100 */
SEC("tc")
int ingress_fwdns_prio100(struct __sk_buff *skb)
{
int skb_type;
skb_type = skb_get_type(skb);
if (skb_type == -1)
return TC_ACT_SHOT;
if (!skb_type)
return TC_ACT_OK;
/* delivery_time is only available to the ingress
* if the tc-bpf checks the skb->tstamp_type.
*/
if (skb->tstamp == EGRESS_ENDHOST_MAGIC)
inc_errs(INGRESS_FWDNS_P100);
if (fwdns_clear_dtime())
skb->tstamp = 0;
return TC_ACT_UNSPEC;
}
/* egress@veth_(src|dst)_fwd@ns_fwd priority 100 */
SEC("tc")
int egress_fwdns_prio100(struct __sk_buff *skb)
{
int skb_type;
skb_type = skb_get_type(skb);
if (skb_type == -1)
return TC_ACT_SHOT;
if (!skb_type)
return TC_ACT_OK;
/* delivery_time is always available to egress even
* the tc-bpf did not use the tstamp_type.
*/
if (skb->tstamp == INGRESS_FWDNS_MAGIC)
inc_dtimes(EGRESS_FWDNS_P100);
else
inc_errs(EGRESS_FWDNS_P100);
if (fwdns_clear_dtime())
skb->tstamp = 0;
return TC_ACT_UNSPEC;
}
/* ingress@veth_(src|dst)_fwd@ns_fwd priority 101 */
SEC("tc")
int ingress_fwdns_prio101(struct __sk_buff *skb)
{
int skb_type;
skb_type = skb_get_type(skb);
if (skb_type == -1 || !skb_type)
/* Should have handled in prio100 */
return TC_ACT_SHOT;
if (skb->tstamp_type) {
if (fwdns_clear_dtime() ||
(skb->tstamp_type != BPF_SKB_CLOCK_MONOTONIC &&
skb->tstamp_type != BPF_SKB_CLOCK_TAI) ||
skb->tstamp != EGRESS_ENDHOST_MAGIC)
inc_errs(INGRESS_FWDNS_P101);
else
inc_dtimes(INGRESS_FWDNS_P101);
} else {
if (!fwdns_clear_dtime())
inc_errs(INGRESS_FWDNS_P101);
}
if (skb->tstamp_type == BPF_SKB_CLOCK_MONOTONIC) {
skb->tstamp = INGRESS_FWDNS_MAGIC;
} else {
if (bpf_skb_set_tstamp(skb, INGRESS_FWDNS_MAGIC,
BPF_SKB_CLOCK_MONOTONIC))
inc_errs(SET_DTIME);
}
if (skb_ns(skb_type) == SRC_NS)
return bpf_fwd() ?
bpf_redirect_neigh(IFINDEX_DST, NULL, 0, 0) : TC_ACT_OK;
else
return bpf_fwd() ?
bpf_redirect_neigh(IFINDEX_SRC, NULL, 0, 0) : TC_ACT_OK;
}
/* egress@veth_(src|dst)_fwd@ns_fwd priority 101 */
SEC("tc")
int egress_fwdns_prio101(struct __sk_buff *skb)
{
int skb_type;
skb_type = skb_get_type(skb);
if (skb_type == -1 || !skb_type)
/* Should have handled in prio100 */
return TC_ACT_SHOT;
if (skb->tstamp_type) {
if (fwdns_clear_dtime() ||
skb->tstamp_type != BPF_SKB_CLOCK_MONOTONIC ||
skb->tstamp != INGRESS_FWDNS_MAGIC)
inc_errs(EGRESS_FWDNS_P101);
else
inc_dtimes(EGRESS_FWDNS_P101);
} else {
if (!fwdns_clear_dtime())
inc_errs(EGRESS_FWDNS_P101);
}
if (skb->tstamp_type == BPF_SKB_CLOCK_MONOTONIC) {
skb->tstamp = EGRESS_FWDNS_MAGIC;
} else {
if (bpf_skb_set_tstamp(skb, EGRESS_FWDNS_MAGIC,
BPF_SKB_CLOCK_MONOTONIC))
inc_errs(SET_DTIME);
}
return TC_ACT_OK;
}
char __license[] SEC("license") = "GPL";
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