1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 4 */ 5 6 #include <stdio.h> 7 #include <unistd.h> 8 #include <stdarg.h> 9 #include <errno.h> 10 #include <stddef.h> 11 #include <string.h> 12 #include <sys/socket.h> 13 #include <sys/wait.h> 14 #include <net_user.h> 15 #include <os.h> 16 #include <um_malloc.h> 17 18 int tap_open_common(void *dev, char *gate_addr) 19 { 20 int tap_addr[4]; 21 22 if (gate_addr == NULL) 23 return 0; 24 if (sscanf(gate_addr, "%d.%d.%d.%d", &tap_addr[0], 25 &tap_addr[1], &tap_addr[2], &tap_addr[3]) != 4) { 26 printk(UM_KERN_ERR "Invalid tap IP address - '%s'\n", 27 gate_addr); 28 return -EINVAL; 29 } 30 return 0; 31 } 32 33 void tap_check_ips(char *gate_addr, unsigned char *eth_addr) 34 { 35 int tap_addr[4]; 36 37 if ((gate_addr != NULL) && 38 (sscanf(gate_addr, "%d.%d.%d.%d", &tap_addr[0], 39 &tap_addr[1], &tap_addr[2], &tap_addr[3]) == 4) && 40 (eth_addr[0] == tap_addr[0]) && 41 (eth_addr[1] == tap_addr[1]) && 42 (eth_addr[2] == tap_addr[2]) && 43 (eth_addr[3] == tap_addr[3])) { 44 printk(UM_KERN_ERR "The tap IP address and the UML eth IP " 45 "address must be different\n"); 46 } 47 } 48 49 /* Do reliable error handling as this fails frequently enough. */ 50 void read_output(int fd, char *output, int len) 51 { 52 int remain, ret, expected; 53 char c; 54 char *str; 55 56 if (output == NULL) { 57 output = &c; 58 len = sizeof(c); 59 } 60 61 *output = '\0'; 62 ret = read(fd, &remain, sizeof(remain)); 63 64 if (ret != sizeof(remain)) { 65 if (ret < 0) 66 ret = -errno; 67 expected = sizeof(remain); 68 str = "length"; 69 goto err; 70 } 71 72 while (remain != 0) { 73 expected = (remain < len) ? remain : len; 74 ret = read(fd, output, expected); 75 if (ret != expected) { 76 if (ret < 0) 77 ret = -errno; 78 str = "data"; 79 goto err; 80 } 81 remain -= ret; 82 } 83 84 return; 85 86 err: 87 if (ret < 0) 88 printk(UM_KERN_ERR "read_output - read of %s failed, " 89 "errno = %d\n", str, -ret); 90 else 91 printk(UM_KERN_ERR "read_output - read of %s failed, read only " 92 "%d of %d bytes\n", str, ret, expected); 93 } 94 95 int net_read(int fd, void *buf, int len) 96 { 97 int n; 98 99 n = read(fd, buf, len); 100 101 if ((n < 0) && (errno == EAGAIN)) 102 return 0; 103 else if (n == 0) 104 return -ENOTCONN; 105 return n; 106 } 107 108 int net_recvfrom(int fd, void *buf, int len) 109 { 110 int n; 111 112 CATCH_EINTR(n = recvfrom(fd, buf, len, 0, NULL, NULL)); 113 if (n < 0) { 114 if (errno == EAGAIN) 115 return 0; 116 return -errno; 117 } 118 else if (n == 0) 119 return -ENOTCONN; 120 return n; 121 } 122 123 int net_write(int fd, void *buf, int len) 124 { 125 int n; 126 127 n = write(fd, buf, len); 128 129 if ((n < 0) && (errno == EAGAIN)) 130 return 0; 131 else if (n == 0) 132 return -ENOTCONN; 133 return n; 134 } 135 136 int net_send(int fd, void *buf, int len) 137 { 138 int n; 139 140 CATCH_EINTR(n = send(fd, buf, len, 0)); 141 if (n < 0) { 142 if (errno == EAGAIN) 143 return 0; 144 return -errno; 145 } 146 else if (n == 0) 147 return -ENOTCONN; 148 return n; 149 } 150 151 int net_sendto(int fd, void *buf, int len, void *to, int sock_len) 152 { 153 int n; 154 155 CATCH_EINTR(n = sendto(fd, buf, len, 0, (struct sockaddr *) to, 156 sock_len)); 157 if (n < 0) { 158 if (errno == EAGAIN) 159 return 0; 160 return -errno; 161 } 162 else if (n == 0) 163 return -ENOTCONN; 164 return n; 165 } 166 167 struct change_pre_exec_data { 168 int close_me; 169 int stdout_fd; 170 }; 171 172 static void change_pre_exec(void *arg) 173 { 174 struct change_pre_exec_data *data = arg; 175 176 close(data->close_me); 177 dup2(data->stdout_fd, 1); 178 } 179 180 static int change_tramp(char **argv, char *output, int output_len) 181 { 182 int pid, fds[2], err; 183 struct change_pre_exec_data pe_data; 184 185 err = os_pipe(fds, 1, 0); 186 if (err < 0) { 187 printk(UM_KERN_ERR "change_tramp - pipe failed, err = %d\n", 188 -err); 189 return err; 190 } 191 pe_data.close_me = fds[0]; 192 pe_data.stdout_fd = fds[1]; 193 pid = run_helper(change_pre_exec, &pe_data, argv); 194 195 if (pid > 0) /* Avoid hang as we won't get data in failure case. */ 196 read_output(fds[0], output, output_len); 197 198 close(fds[0]); 199 close(fds[1]); 200 201 if (pid > 0) 202 helper_wait(pid); 203 return pid; 204 } 205 206 static void change(char *dev, char *what, unsigned char *addr, 207 unsigned char *netmask) 208 { 209 char addr_buf[sizeof("255.255.255.255\0")]; 210 char netmask_buf[sizeof("255.255.255.255\0")]; 211 char version[sizeof("nnnnn\0")]; 212 char *argv[] = { "uml_net", version, what, dev, addr_buf, 213 netmask_buf, NULL }; 214 char *output; 215 int output_len, pid; 216 217 sprintf(version, "%d", UML_NET_VERSION); 218 sprintf(addr_buf, "%d.%d.%d.%d", addr[0], addr[1], addr[2], addr[3]); 219 sprintf(netmask_buf, "%d.%d.%d.%d", netmask[0], netmask[1], 220 netmask[2], netmask[3]); 221 222 output_len = UM_KERN_PAGE_SIZE; 223 output = uml_kmalloc(output_len, UM_GFP_KERNEL); 224 if (output == NULL) 225 printk(UM_KERN_ERR "change : failed to allocate output " 226 "buffer\n"); 227 228 pid = change_tramp(argv, output, output_len); 229 if (pid < 0) { 230 kfree(output); 231 return; 232 } 233 234 if (output != NULL) { 235 printk("%s", output); 236 kfree(output); 237 } 238 } 239 240 void open_addr(unsigned char *addr, unsigned char *netmask, void *arg) 241 { 242 change(arg, "add", addr, netmask); 243 } 244 245 void close_addr(unsigned char *addr, unsigned char *netmask, void *arg) 246 { 247 change(arg, "del", addr, netmask); 248 } 249 250 char *split_if_spec(char *str, ...) 251 { 252 char **arg, *end, *ret = NULL; 253 va_list ap; 254 255 va_start(ap, str); 256 while ((arg = va_arg(ap, char **)) != NULL) { 257 if (*str == '\0') 258 goto out; 259 end = strchr(str, ','); 260 if (end != str) 261 *arg = str; 262 if (end == NULL) 263 goto out; 264 *end++ = '\0'; 265 str = end; 266 } 267 ret = str; 268 out: 269 va_end(ap); 270 return ret; 271 } 272