1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. */
#define KBUILD_MODNAME "foo"
#include <stddef.h>
#include <string.h>
#include <linux/bpf.h>
#include <linux/icmp.h>
#include <linux/in.h>
#include <linux/if_ether.h>
#include <linux/if_packet.h>
#include <linux/if_vlan.h>
#include <linux/ip.h>
#include "bpf_helpers.h"
#include "bpf_endian.h"
#include "xdping.h"
struct bpf_map_def SEC("maps") ping_map = {
.type = BPF_MAP_TYPE_HASH,
.key_size = sizeof(__u32),
.value_size = sizeof(struct pinginfo),
.max_entries = 256,
};
static __always_inline void swap_src_dst_mac(void *data)
{
unsigned short *p = data;
unsigned short dst[3];
dst[0] = p[0];
dst[1] = p[1];
dst[2] = p[2];
p[0] = p[3];
p[1] = p[4];
p[2] = p[5];
p[3] = dst[0];
p[4] = dst[1];
p[5] = dst[2];
}
static __always_inline __u16 csum_fold_helper(__wsum sum)
{
sum = (sum & 0xffff) + (sum >> 16);
return ~((sum & 0xffff) + (sum >> 16));
}
static __always_inline __u16 ipv4_csum(void *data_start, int data_size)
{
__wsum sum;
sum = bpf_csum_diff(0, 0, data_start, data_size, 0);
return csum_fold_helper(sum);
}
#define ICMP_ECHO_LEN 64
static __always_inline int icmp_check(struct xdp_md *ctx, int type)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
struct ethhdr *eth = data;
struct icmphdr *icmph;
struct iphdr *iph;
if (data + sizeof(*eth) + sizeof(*iph) + ICMP_ECHO_LEN > data_end)
return XDP_PASS;
if (eth->h_proto != bpf_htons(ETH_P_IP))
return XDP_PASS;
iph = data + sizeof(*eth);
if (iph->protocol != IPPROTO_ICMP)
return XDP_PASS;
if (bpf_ntohs(iph->tot_len) - sizeof(*iph) != ICMP_ECHO_LEN)
return XDP_PASS;
icmph = data + sizeof(*eth) + sizeof(*iph);
if (icmph->type != type)
return XDP_PASS;
return XDP_TX;
}
SEC("xdpclient")
int xdping_client(struct xdp_md *ctx)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
struct pinginfo *pinginfo = NULL;
struct ethhdr *eth = data;
struct icmphdr *icmph;
struct iphdr *iph;
__u64 recvtime;
__be32 raddr;
__be16 seq;
int ret;
__u8 i;
ret = icmp_check(ctx, ICMP_ECHOREPLY);
if (ret != XDP_TX)
return ret;
iph = data + sizeof(*eth);
icmph = data + sizeof(*eth) + sizeof(*iph);
raddr = iph->saddr;
/* Record time reply received. */
recvtime = bpf_ktime_get_ns();
pinginfo = bpf_map_lookup_elem(&ping_map, &raddr);
if (!pinginfo || pinginfo->seq != icmph->un.echo.sequence)
return XDP_PASS;
if (pinginfo->start) {
#pragma clang loop unroll(full)
for (i = 0; i < XDPING_MAX_COUNT; i++) {
if (pinginfo->times[i] == 0)
break;
}
/* verifier is fussy here... */
if (i < XDPING_MAX_COUNT) {
pinginfo->times[i] = recvtime -
pinginfo->start;
pinginfo->start = 0;
i++;
}
/* No more space for values? */
if (i == pinginfo->count || i == XDPING_MAX_COUNT)
return XDP_PASS;
}
/* Now convert reply back into echo request. */
swap_src_dst_mac(data);
iph->saddr = iph->daddr;
iph->daddr = raddr;
icmph->type = ICMP_ECHO;
seq = bpf_htons(bpf_ntohs(icmph->un.echo.sequence) + 1);
icmph->un.echo.sequence = seq;
icmph->checksum = 0;
icmph->checksum = ipv4_csum(icmph, ICMP_ECHO_LEN);
pinginfo->seq = seq;
pinginfo->start = bpf_ktime_get_ns();
return XDP_TX;
}
SEC("xdpserver")
int xdping_server(struct xdp_md *ctx)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
struct ethhdr *eth = data;
struct icmphdr *icmph;
struct iphdr *iph;
__be32 raddr;
int ret;
ret = icmp_check(ctx, ICMP_ECHO);
if (ret != XDP_TX)
return ret;
iph = data + sizeof(*eth);
icmph = data + sizeof(*eth) + sizeof(*iph);
raddr = iph->saddr;
/* Now convert request into echo reply. */
swap_src_dst_mac(data);
iph->saddr = iph->daddr;
iph->daddr = raddr;
icmph->type = ICMP_ECHOREPLY;
icmph->checksum = 0;
icmph->checksum = ipv4_csum(icmph, ICMP_ECHO_LEN);
return XDP_TX;
}
char _license[] SEC("license") = "GPL";
|
