1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <string.h>
4
5 #include <linux/stddef.h>
6 #include <linux/bpf.h>
7 #include <linux/in.h>
8 #include <linux/in6.h>
9 #include <linux/if.h>
10 #include <errno.h>
11
12 #include <bpf/bpf_helpers.h>
13 #include <bpf/bpf_endian.h>
14
15 #define SERV6_IP_0 0xfaceb00c /* face:b00c:1234:5678::abcd */
16 #define SERV6_IP_1 0x12345678
17 #define SERV6_IP_2 0x00000000
18 #define SERV6_IP_3 0x0000abcd
19 #define SERV6_PORT 6060
20 #define SERV6_REWRITE_IP_0 0x00000000
21 #define SERV6_REWRITE_IP_1 0x00000000
22 #define SERV6_REWRITE_IP_2 0x00000000
23 #define SERV6_REWRITE_IP_3 0x00000001
24 #define SERV6_REWRITE_PORT 6666
25
26 #ifndef IFNAMSIZ
27 #define IFNAMSIZ 16
28 #endif
29
bind_to_device(struct bpf_sock_addr * ctx)30 static __inline int bind_to_device(struct bpf_sock_addr *ctx)
31 {
32 char veth1[IFNAMSIZ] = "test_sock_addr1";
33 char veth2[IFNAMSIZ] = "test_sock_addr2";
34 char missing[IFNAMSIZ] = "nonexistent_dev";
35 char del_bind[IFNAMSIZ] = "";
36 int veth1_idx, veth2_idx;
37
38 if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
39 &veth1, sizeof(veth1)))
40 return 1;
41 if (bpf_getsockopt(ctx, SOL_SOCKET, SO_BINDTOIFINDEX,
42 &veth1_idx, sizeof(veth1_idx)) || !veth1_idx)
43 return 1;
44 if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
45 &veth2, sizeof(veth2)))
46 return 1;
47 if (bpf_getsockopt(ctx, SOL_SOCKET, SO_BINDTOIFINDEX,
48 &veth2_idx, sizeof(veth2_idx)) || !veth2_idx ||
49 veth1_idx == veth2_idx)
50 return 1;
51 if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
52 &missing, sizeof(missing)) != -ENODEV)
53 return 1;
54 if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTOIFINDEX,
55 &veth1_idx, sizeof(veth1_idx)))
56 return 1;
57 if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
58 &del_bind, sizeof(del_bind)))
59 return 1;
60
61 return 0;
62 }
63
bind_reuseport(struct bpf_sock_addr * ctx)64 static __inline int bind_reuseport(struct bpf_sock_addr *ctx)
65 {
66 int val = 1;
67
68 if (bpf_setsockopt(ctx, SOL_SOCKET, SO_REUSEPORT,
69 &val, sizeof(val)))
70 return 1;
71 if (bpf_getsockopt(ctx, SOL_SOCKET, SO_REUSEPORT,
72 &val, sizeof(val)) || !val)
73 return 1;
74 val = 0;
75 if (bpf_setsockopt(ctx, SOL_SOCKET, SO_REUSEPORT,
76 &val, sizeof(val)))
77 return 1;
78 if (bpf_getsockopt(ctx, SOL_SOCKET, SO_REUSEPORT,
79 &val, sizeof(val)) || val)
80 return 1;
81
82 return 0;
83 }
84
misc_opts(struct bpf_sock_addr * ctx,int opt)85 static __inline int misc_opts(struct bpf_sock_addr *ctx, int opt)
86 {
87 int old, tmp, new = 0xeb9f;
88
89 /* Socket in test case has guarantee that old never equals to new. */
90 if (bpf_getsockopt(ctx, SOL_SOCKET, opt, &old, sizeof(old)) ||
91 old == new)
92 return 1;
93 if (bpf_setsockopt(ctx, SOL_SOCKET, opt, &new, sizeof(new)))
94 return 1;
95 if (bpf_getsockopt(ctx, SOL_SOCKET, opt, &tmp, sizeof(tmp)) ||
96 tmp != new)
97 return 1;
98 if (bpf_setsockopt(ctx, SOL_SOCKET, opt, &old, sizeof(old)))
99 return 1;
100
101 return 0;
102 }
103
104 SEC("cgroup/bind6")
bind_v6_prog(struct bpf_sock_addr * ctx)105 int bind_v6_prog(struct bpf_sock_addr *ctx)
106 {
107 struct bpf_sock *sk;
108 __u32 user_ip6;
109 __u16 user_port;
110 int i;
111
112 sk = ctx->sk;
113 if (!sk)
114 return 0;
115
116 if (sk->family != AF_INET6)
117 return 0;
118
119 if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM)
120 return 0;
121
122 if (ctx->user_ip6[0] != bpf_htonl(SERV6_IP_0) ||
123 ctx->user_ip6[1] != bpf_htonl(SERV6_IP_1) ||
124 ctx->user_ip6[2] != bpf_htonl(SERV6_IP_2) ||
125 ctx->user_ip6[3] != bpf_htonl(SERV6_IP_3) ||
126 ctx->user_port != bpf_htons(SERV6_PORT))
127 return 0;
128
129 // u8 narrow loads:
130 for (i = 0; i < 4; i++) {
131 user_ip6 = 0;
132 user_ip6 |= ((volatile __u8 *)&ctx->user_ip6[i])[0] << 0;
133 user_ip6 |= ((volatile __u8 *)&ctx->user_ip6[i])[1] << 8;
134 user_ip6 |= ((volatile __u8 *)&ctx->user_ip6[i])[2] << 16;
135 user_ip6 |= ((volatile __u8 *)&ctx->user_ip6[i])[3] << 24;
136 if (ctx->user_ip6[i] != user_ip6)
137 return 0;
138 }
139
140 user_port = 0;
141 user_port |= ((volatile __u8 *)&ctx->user_port)[0] << 0;
142 user_port |= ((volatile __u8 *)&ctx->user_port)[1] << 8;
143 if (ctx->user_port != user_port)
144 return 0;
145
146 // u16 narrow loads:
147 for (i = 0; i < 4; i++) {
148 user_ip6 = 0;
149 user_ip6 |= ((volatile __u16 *)&ctx->user_ip6[i])[0] << 0;
150 user_ip6 |= ((volatile __u16 *)&ctx->user_ip6[i])[1] << 16;
151 if (ctx->user_ip6[i] != user_ip6)
152 return 0;
153 }
154
155 /* Bind to device and unbind it. */
156 if (bind_to_device(ctx))
157 return 0;
158
159 /* Test for misc socket options. */
160 if (misc_opts(ctx, SO_MARK) || misc_opts(ctx, SO_PRIORITY))
161 return 0;
162
163 /* Set reuseport and unset */
164 if (bind_reuseport(ctx))
165 return 0;
166
167 ctx->user_ip6[0] = bpf_htonl(SERV6_REWRITE_IP_0);
168 ctx->user_ip6[1] = bpf_htonl(SERV6_REWRITE_IP_1);
169 ctx->user_ip6[2] = bpf_htonl(SERV6_REWRITE_IP_2);
170 ctx->user_ip6[3] = bpf_htonl(SERV6_REWRITE_IP_3);
171 ctx->user_port = bpf_htons(SERV6_REWRITE_PORT);
172
173 return 1;
174 }
175
176 char _license[] SEC("license") = "GPL";
177