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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 | // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2018 Facebook #include <string.h> #include <linux/stddef.h> #include <linux/bpf.h> #include <linux/in.h> #include <linux/in6.h> #include <linux/tcp.h> #include <linux/if.h> #include <errno.h> #include <bpf/bpf_helpers.h> #include <bpf/bpf_endian.h> #include "bpf_tcp_helpers.h" #define SRC_REWRITE_IP4 0x7f000004U #define DST_REWRITE_IP4 0x7f000001U #define DST_REWRITE_PORT4 4444 #ifndef TCP_CA_NAME_MAX #define TCP_CA_NAME_MAX 16 #endif #ifndef TCP_NOTSENT_LOWAT #define TCP_NOTSENT_LOWAT 25 #endif #ifndef IFNAMSIZ #define IFNAMSIZ 16 #endif __attribute__ ((noinline)) __weak int do_bind(struct bpf_sock_addr *ctx) { struct sockaddr_in sa = {}; sa.sin_family = AF_INET; sa.sin_port = bpf_htons(0); sa.sin_addr.s_addr = bpf_htonl(SRC_REWRITE_IP4); if (bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)) != 0) return 0; return 1; } static __inline int verify_cc(struct bpf_sock_addr *ctx, char expected[TCP_CA_NAME_MAX]) { char buf[TCP_CA_NAME_MAX]; int i; if (bpf_getsockopt(ctx, SOL_TCP, TCP_CONGESTION, &buf, sizeof(buf))) return 1; for (i = 0; i < TCP_CA_NAME_MAX; i++) { if (buf[i] != expected[i]) return 1; if (buf[i] == 0) break; } return 0; } static __inline int set_cc(struct bpf_sock_addr *ctx) { char reno[TCP_CA_NAME_MAX] = "reno"; char cubic[TCP_CA_NAME_MAX] = "cubic"; if (bpf_setsockopt(ctx, SOL_TCP, TCP_CONGESTION, &reno, sizeof(reno))) return 1; if (verify_cc(ctx, reno)) return 1; if (bpf_setsockopt(ctx, SOL_TCP, TCP_CONGESTION, &cubic, sizeof(cubic))) return 1; if (verify_cc(ctx, cubic)) return 1; return 0; } 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] = ""; if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE, &veth1, sizeof(veth1))) return 1; if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE, &veth2, sizeof(veth2))) return 1; if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE, &missing, sizeof(missing)) != -ENODEV) return 1; if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE, &del_bind, sizeof(del_bind))) return 1; return 0; } static __inline int set_keepalive(struct bpf_sock_addr *ctx) { int zero = 0, one = 1; if (bpf_setsockopt(ctx, SOL_SOCKET, SO_KEEPALIVE, &one, sizeof(one))) return 1; if (ctx->type == SOCK_STREAM) { if (bpf_setsockopt(ctx, SOL_TCP, TCP_KEEPIDLE, &one, sizeof(one))) return 1; if (bpf_setsockopt(ctx, SOL_TCP, TCP_KEEPINTVL, &one, sizeof(one))) return 1; if (bpf_setsockopt(ctx, SOL_TCP, TCP_KEEPCNT, &one, sizeof(one))) return 1; if (bpf_setsockopt(ctx, SOL_TCP, TCP_SYNCNT, &one, sizeof(one))) return 1; if (bpf_setsockopt(ctx, SOL_TCP, TCP_USER_TIMEOUT, &one, sizeof(one))) return 1; } if (bpf_setsockopt(ctx, SOL_SOCKET, SO_KEEPALIVE, &zero, sizeof(zero))) return 1; return 0; } static __inline int set_notsent_lowat(struct bpf_sock_addr *ctx) { int lowat = 65535; if (ctx->type == SOCK_STREAM) { if (bpf_setsockopt(ctx, SOL_TCP, TCP_NOTSENT_LOWAT, &lowat, sizeof(lowat))) return 1; } return 0; } SEC("cgroup/connect4") int connect_v4_prog(struct bpf_sock_addr *ctx) { struct bpf_sock_tuple tuple = {}; struct bpf_sock *sk; /* Verify that new destination is available. */ memset(&tuple.ipv4.saddr, 0, sizeof(tuple.ipv4.saddr)); memset(&tuple.ipv4.sport, 0, sizeof(tuple.ipv4.sport)); tuple.ipv4.daddr = bpf_htonl(DST_REWRITE_IP4); tuple.ipv4.dport = bpf_htons(DST_REWRITE_PORT4); /* Bind to device and unbind it. */ if (bind_to_device(ctx)) return 0; if (set_keepalive(ctx)) return 0; if (set_notsent_lowat(ctx)) return 0; if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM) return 0; else if (ctx->type == SOCK_STREAM) sk = bpf_sk_lookup_tcp(ctx, &tuple, sizeof(tuple.ipv4), BPF_F_CURRENT_NETNS, 0); else sk = bpf_sk_lookup_udp(ctx, &tuple, sizeof(tuple.ipv4), BPF_F_CURRENT_NETNS, 0); if (!sk) return 0; if (sk->src_ip4 != tuple.ipv4.daddr || sk->src_port != DST_REWRITE_PORT4) { bpf_sk_release(sk); return 0; } bpf_sk_release(sk); /* Rewrite congestion control. */ if (ctx->type == SOCK_STREAM && set_cc(ctx)) return 0; /* Rewrite destination. */ ctx->user_ip4 = bpf_htonl(DST_REWRITE_IP4); ctx->user_port = bpf_htons(DST_REWRITE_PORT4); return do_bind(ctx) ? 1 : 0; } char _license[] SEC("license") = "GPL"; |