arch/um/drivers/net_user.c

   1 /*
   2  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   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 }