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
|
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2022 Intel */
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include <linux/if_ether.h>
#include <linux/ip.h>
#include <linux/errno.h>
#include "xsk_xdp_common.h"
struct {
__uint(type, BPF_MAP_TYPE_XSKMAP);
__uint(max_entries, 2);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
} xsk SEC(".maps");
static unsigned int idx;
int adjust_value = 0;
int count = 0;
SEC("xdp.frags") int xsk_def_prog(struct xdp_md *xdp)
{
return bpf_redirect_map(&xsk, 0, XDP_DROP);
}
SEC("xdp.frags") int xsk_xdp_drop(struct xdp_md *xdp)
{
/* Drop every other packet */
if (idx++ % 2)
return XDP_DROP;
return bpf_redirect_map(&xsk, 0, XDP_DROP);
}
SEC("xdp.frags") int xsk_xdp_populate_metadata(struct xdp_md *xdp)
{
void *data, *data_meta;
struct xdp_info *meta;
int err;
/* Reserve enough for all custom metadata. */
err = bpf_xdp_adjust_meta(xdp, -(int)sizeof(struct xdp_info));
if (err)
return XDP_DROP;
data = (void *)(long)xdp->data;
data_meta = (void *)(long)xdp->data_meta;
if (data_meta + sizeof(struct xdp_info) > data)
return XDP_DROP;
meta = data_meta;
meta->count = count++;
return bpf_redirect_map(&xsk, 0, XDP_DROP);
}
SEC("xdp") int xsk_xdp_shared_umem(struct xdp_md *xdp)
{
void *data = (void *)(long)xdp->data;
void *data_end = (void *)(long)xdp->data_end;
struct ethhdr *eth = data;
if (eth + 1 > data_end)
return XDP_DROP;
/* Redirecting packets based on the destination MAC address */
idx = ((unsigned int)(eth->h_dest[5])) / 2;
if (idx > MAX_SOCKETS)
return XDP_DROP;
return bpf_redirect_map(&xsk, idx, XDP_DROP);
}
SEC("xdp.frags") int xsk_xdp_adjust_tail(struct xdp_md *xdp)
{
__u32 buff_len, curr_buff_len;
int ret;
buff_len = bpf_xdp_get_buff_len(xdp);
if (buff_len == 0)
return XDP_DROP;
ret = bpf_xdp_adjust_tail(xdp, adjust_value);
if (ret < 0) {
/* Handle unsupported cases */
if (ret == -EOPNOTSUPP) {
/* Set adjust_value to -EOPNOTSUPP to indicate to userspace that this case
* is unsupported
*/
adjust_value = -EOPNOTSUPP;
return bpf_redirect_map(&xsk, 0, XDP_DROP);
}
return XDP_DROP;
}
curr_buff_len = bpf_xdp_get_buff_len(xdp);
if (curr_buff_len != buff_len + adjust_value)
return XDP_DROP;
if (curr_buff_len > buff_len) {
__u32 *pkt_data = (void *)(long)xdp->data;
__u32 len, words_to_end, seq_num;
len = curr_buff_len - PKT_HDR_ALIGN;
words_to_end = len / sizeof(*pkt_data) - 1;
seq_num = words_to_end;
/* Convert sequence number to network byte order. Store this in the last 4 bytes of
* the packet. Use 'adjust_value' to determine the position at the end of the
* packet for storing the sequence number.
*/
seq_num = __constant_htonl(words_to_end);
bpf_xdp_store_bytes(xdp, curr_buff_len - sizeof(seq_num), &seq_num,
sizeof(seq_num));
}
return bpf_redirect_map(&xsk, 0, XDP_DROP);
}
char _license[] SEC("license") = "GPL";
|
