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