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