1 // SPDX-License-Identifier: GPL-2.0 2 /* Test IPV6_FLOWINFO cmsg on send and recv */ 3 4 #define _GNU_SOURCE 5 6 #include <arpa/inet.h> 7 #include <asm/byteorder.h> 8 #include <error.h> 9 #include <errno.h> 10 #include <fcntl.h> 11 #include <limits.h> 12 #include <linux/in6.h> 13 #include <stdbool.h> 14 #include <stdio.h> 15 #include <stdint.h> 16 #include <stdlib.h> 17 #include <string.h> 18 #include <sys/socket.h> 19 #include <sys/stat.h> 20 #include <sys/time.h> 21 #include <sys/types.h> 22 #include <unistd.h> 23 24 /* uapi/glibc weirdness may leave this undefined */ 25 #ifndef IPV6_FLOWINFO 26 #define IPV6_FLOWINFO 11 27 #endif 28 29 #ifndef IPV6_FLOWLABEL_MGR 30 #define IPV6_FLOWLABEL_MGR 32 31 #endif 32 33 #define FLOWLABEL_WILDCARD ((uint32_t) -1) 34 35 static const char cfg_data[] = "a"; 36 static uint32_t cfg_label = 1; 37 38 static void do_send(int fd, bool with_flowlabel, uint32_t flowlabel) 39 { 40 char control[CMSG_SPACE(sizeof(flowlabel))] = {0}; 41 struct msghdr msg = {0}; 42 struct iovec iov = {0}; 43 int ret; 44 45 iov.iov_base = (char *)cfg_data; 46 iov.iov_len = sizeof(cfg_data); 47 48 msg.msg_iov = &iov; 49 msg.msg_iovlen = 1; 50 51 if (with_flowlabel) { 52 struct cmsghdr *cm; 53 54 cm = (void *)control; 55 cm->cmsg_len = CMSG_LEN(sizeof(flowlabel)); 56 cm->cmsg_level = SOL_IPV6; 57 cm->cmsg_type = IPV6_FLOWINFO; 58 *(uint32_t *)CMSG_DATA(cm) = htonl(flowlabel); 59 60 msg.msg_control = control; 61 msg.msg_controllen = sizeof(control); 62 } 63 64 ret = sendmsg(fd, &msg, 0); 65 if (ret == -1) 66 error(1, errno, "send"); 67 68 if (with_flowlabel) 69 fprintf(stderr, "sent with label %u\n", flowlabel); 70 else 71 fprintf(stderr, "sent without label\n"); 72 } 73 74 static void do_recv(int fd, bool with_flowlabel, uint32_t expect) 75 { 76 char control[CMSG_SPACE(sizeof(expect))]; 77 char data[sizeof(cfg_data)]; 78 struct msghdr msg = {0}; 79 struct iovec iov = {0}; 80 struct cmsghdr *cm; 81 uint32_t flowlabel; 82 int ret; 83 84 iov.iov_base = data; 85 iov.iov_len = sizeof(data); 86 87 msg.msg_iov = &iov; 88 msg.msg_iovlen = 1; 89 90 memset(control, 0, sizeof(control)); 91 msg.msg_control = control; 92 msg.msg_controllen = sizeof(control); 93 94 ret = recvmsg(fd, &msg, 0); 95 if (ret == -1) 96 error(1, errno, "recv"); 97 if (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC)) 98 error(1, 0, "recv: truncated"); 99 if (ret != sizeof(cfg_data)) 100 error(1, 0, "recv: length mismatch"); 101 if (memcmp(data, cfg_data, sizeof(data))) 102 error(1, 0, "recv: data mismatch"); 103 104 cm = CMSG_FIRSTHDR(&msg); 105 if (with_flowlabel) { 106 if (!cm) 107 error(1, 0, "recv: missing cmsg"); 108 if (CMSG_NXTHDR(&msg, cm)) 109 error(1, 0, "recv: too many cmsg"); 110 if (cm->cmsg_level != SOL_IPV6 || 111 cm->cmsg_type != IPV6_FLOWINFO) 112 error(1, 0, "recv: unexpected cmsg level or type"); 113 114 flowlabel = ntohl(*(uint32_t *)CMSG_DATA(cm)); 115 fprintf(stderr, "recv with label %u\n", flowlabel); 116 117 if (expect != FLOWLABEL_WILDCARD && expect != flowlabel) 118 fprintf(stderr, "recv: incorrect flowlabel %u != %u\n", 119 flowlabel, expect); 120 121 } else { 122 fprintf(stderr, "recv without label\n"); 123 } 124 } 125 126 static bool get_autoflowlabel_enabled(void) 127 { 128 int fd, ret; 129 char val; 130 131 fd = open("/proc/sys/net/ipv6/auto_flowlabels", O_RDONLY); 132 if (fd == -1) 133 error(1, errno, "open sysctl"); 134 135 ret = read(fd, &val, 1); 136 if (ret == -1) 137 error(1, errno, "read sysctl"); 138 if (ret == 0) 139 error(1, 0, "read sysctl: 0"); 140 141 if (close(fd)) 142 error(1, errno, "close sysctl"); 143 144 return val == '1'; 145 } 146 147 static void flowlabel_get(int fd, uint32_t label, uint8_t share, uint16_t flags) 148 { 149 struct in6_flowlabel_req req = { 150 .flr_action = IPV6_FL_A_GET, 151 .flr_label = htonl(label), 152 .flr_flags = flags, 153 .flr_share = share, 154 }; 155 156 /* do not pass IPV6_ADDR_ANY or IPV6_ADDR_MAPPED */ 157 req.flr_dst.s6_addr[0] = 0xfd; 158 req.flr_dst.s6_addr[15] = 0x1; 159 160 if (setsockopt(fd, SOL_IPV6, IPV6_FLOWLABEL_MGR, &req, sizeof(req))) 161 error(1, errno, "setsockopt flowlabel get"); 162 } 163 164 static void parse_opts(int argc, char **argv) 165 { 166 int c; 167 168 while ((c = getopt(argc, argv, "l:")) != -1) { 169 switch (c) { 170 case 'l': 171 cfg_label = strtoul(optarg, NULL, 0); 172 break; 173 default: 174 error(1, 0, "%s: parse error", argv[0]); 175 } 176 } 177 } 178 179 int main(int argc, char **argv) 180 { 181 struct sockaddr_in6 addr = { 182 .sin6_family = AF_INET6, 183 .sin6_port = htons(8000), 184 .sin6_addr = IN6ADDR_LOOPBACK_INIT, 185 }; 186 const int one = 1; 187 int fdt, fdr; 188 189 parse_opts(argc, argv); 190 191 fdt = socket(PF_INET6, SOCK_DGRAM, 0); 192 if (fdt == -1) 193 error(1, errno, "socket t"); 194 195 fdr = socket(PF_INET6, SOCK_DGRAM, 0); 196 if (fdr == -1) 197 error(1, errno, "socket r"); 198 199 if (connect(fdt, (void *)&addr, sizeof(addr))) 200 error(1, errno, "connect"); 201 if (bind(fdr, (void *)&addr, sizeof(addr))) 202 error(1, errno, "bind"); 203 204 flowlabel_get(fdt, cfg_label, IPV6_FL_S_EXCL, IPV6_FL_F_CREATE); 205 206 if (setsockopt(fdr, SOL_IPV6, IPV6_FLOWINFO, &one, sizeof(one))) 207 error(1, errno, "setsockopt flowinfo"); 208 209 if (get_autoflowlabel_enabled()) { 210 fprintf(stderr, "send no label: recv auto flowlabel\n"); 211 do_send(fdt, false, 0); 212 do_recv(fdr, true, FLOWLABEL_WILDCARD); 213 } else { 214 fprintf(stderr, "send no label: recv no label (auto off)\n"); 215 do_send(fdt, false, 0); 216 do_recv(fdr, false, 0); 217 } 218 219 fprintf(stderr, "send label\n"); 220 do_send(fdt, true, cfg_label); 221 do_recv(fdr, true, cfg_label); 222 223 if (close(fdr)) 224 error(1, errno, "close r"); 225 if (close(fdt)) 226 error(1, errno, "close t"); 227 228 return 0; 229 } 230