Loading...
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 | // SPDX-License-Identifier: GPL-2.0 #include <string.h> #include <linux/stddef.h> #include <linux/bpf.h> #include <linux/in.h> #include <linux/in6.h> #include <sys/socket.h> #include <netinet/tcp.h> #include <linux/if.h> #include <errno.h> #include <bpf/bpf_helpers.h> #include <bpf/bpf_endian.h> #define SERV4_IP 0xc0a801feU /* 192.168.1.254 */ #define SERV4_PORT 4040 #define SERV4_REWRITE_IP 0x7f000001U /* 127.0.0.1 */ #define SERV4_REWRITE_PORT 4444 #ifndef IFNAMSIZ #define IFNAMSIZ 16 #endif static __inline int bind_to_device(struct bpf_sock_addr *ctx) { char veth1[IFNAMSIZ] = "test_sock_addr1"; char veth2[IFNAMSIZ] = "test_sock_addr2"; char missing[IFNAMSIZ] = "nonexistent_dev"; char del_bind[IFNAMSIZ] = ""; int veth1_idx, veth2_idx; if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE, &veth1, sizeof(veth1))) return 1; if (bpf_getsockopt(ctx, SOL_SOCKET, SO_BINDTOIFINDEX, &veth1_idx, sizeof(veth1_idx)) || !veth1_idx) return 1; if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE, &veth2, sizeof(veth2))) return 1; if (bpf_getsockopt(ctx, SOL_SOCKET, SO_BINDTOIFINDEX, &veth2_idx, sizeof(veth2_idx)) || !veth2_idx || veth1_idx == veth2_idx) return 1; if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE, &missing, sizeof(missing)) != -ENODEV) return 1; if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTOIFINDEX, &veth1_idx, sizeof(veth1_idx))) return 1; if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE, &del_bind, sizeof(del_bind))) return 1; return 0; } static __inline int bind_reuseport(struct bpf_sock_addr *ctx) { int val = 1; if (bpf_setsockopt(ctx, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val))) return 1; if (bpf_getsockopt(ctx, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val)) || !val) return 1; val = 0; if (bpf_setsockopt(ctx, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val))) return 1; if (bpf_getsockopt(ctx, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val)) || val) return 1; return 0; } static __inline int misc_opts(struct bpf_sock_addr *ctx, int opt) { int old, tmp, new = 0xeb9f; /* Socket in test case has guarantee that old never equals to new. */ if (bpf_getsockopt(ctx, SOL_SOCKET, opt, &old, sizeof(old)) || old == new) return 1; if (bpf_setsockopt(ctx, SOL_SOCKET, opt, &new, sizeof(new))) return 1; if (bpf_getsockopt(ctx, SOL_SOCKET, opt, &tmp, sizeof(tmp)) || tmp != new) return 1; if (bpf_setsockopt(ctx, SOL_SOCKET, opt, &old, sizeof(old))) return 1; return 0; } SEC("cgroup/bind4") int bind_v4_prog(struct bpf_sock_addr *ctx) { struct bpf_sock *sk; __u32 user_ip4; __u16 user_port; sk = ctx->sk; if (!sk) return 0; if (sk->family != AF_INET) return 0; if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM) return 0; if (ctx->user_ip4 != bpf_htonl(SERV4_IP) || ctx->user_port != bpf_htons(SERV4_PORT)) return 0; // u8 narrow loads: user_ip4 = 0; user_ip4 |= ((volatile __u8 *)&ctx->user_ip4)[0] << 0; user_ip4 |= ((volatile __u8 *)&ctx->user_ip4)[1] << 8; user_ip4 |= ((volatile __u8 *)&ctx->user_ip4)[2] << 16; user_ip4 |= ((volatile __u8 *)&ctx->user_ip4)[3] << 24; if (ctx->user_ip4 != user_ip4) return 0; user_port = 0; user_port |= ((volatile __u8 *)&ctx->user_port)[0] << 0; user_port |= ((volatile __u8 *)&ctx->user_port)[1] << 8; if (ctx->user_port != user_port) return 0; // u16 narrow loads: user_ip4 = 0; user_ip4 |= ((volatile __u16 *)&ctx->user_ip4)[0] << 0; user_ip4 |= ((volatile __u16 *)&ctx->user_ip4)[1] << 16; if (ctx->user_ip4 != user_ip4) return 0; /* Bind to device and unbind it. */ if (bind_to_device(ctx)) return 0; /* Test for misc socket options. */ if (misc_opts(ctx, SO_MARK) || misc_opts(ctx, SO_PRIORITY)) return 0; /* Set reuseport and unset */ if (bind_reuseport(ctx)) return 0; ctx->user_ip4 = bpf_htonl(SERV4_REWRITE_IP); ctx->user_port = bpf_htons(SERV4_REWRITE_PORT); return 1; } char _license[] SEC("license") = "GPL"; |