klibc-utils/ipconfig.c.txt

   1 /*
   2  * Copyright (c) 2017 Denys Vlasenko <vda.linux@googlemail.com>
   3  *
   4  * Licensed under GPLv2, see file LICENSE in this source tree.
   5  */
   6 //config:config IPCONFIG
   7 //config:       bool "ipconfig"
   8 //config:       default y
   9 //config:       help
  10 //config:       (Auto)configure network.
  11
  12 //applet:IF_IPCONFIG(APPLET(ipconfig, BB_DIR_BIN, BB_SUID_DROP))
  13
  14 //kbuild:lib-$(CONFIG_IPCONFIG) += ipconfig.o
  15
  16 #include <net/if.h>
  17 #include "libbb.h"
  18
  19 struct globals {
  20         int fixed;
  21         const char *hostname;
  22 };
  23 #define G (*ptr_to_globals)
  24 #define INIT_G() do { \
  25         SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
  26 } while (0)
  27
  28 struct dev {
  29         const char *name;
  30         uint8_t  fixed;
  31         uint32_t ip_addr;
  32         uint32_t ip_netmask;
  33         uint32_t ip_server;
  34         uint32_t ip_router;
  35 };
  36
  37 static int
  38 parse_method(const char *method)
  39 {
  40         int fixed;
  41
  42         fixed = (method[0] != '\0');
  43         if (fixed) {
  44                 /* if it's not "" */
  45                 fixed = index_in_strings(
  46                         /* 0 */ "on""\0"
  47                         /* 1 */ "any""\0"
  48                         /* 2 */ "both""\0"
  49                         /* 3 */ "dhcp""\0"
  50                         /* 4 */ "bootp""\0"
  51                         /* 5 */ "rarp""\0"
  52                         /* 6 */ "none""\0"
  53                         /* 7 */ "static""\0"
  54                         /* 8 */ "off""\0"
  55                         , method
  56                 );
  57                 if (fixed > 0)
  58                         fixed /= 6;
  59         }
  60         return fixed;
  61 }
  62
  63 static uint32_t
  64 parse_addr(const char *ip)
  65 {
  66         struct in_addr in;
  67         if (inet_aton(ip, &in) == 0)
  68                 bb_error_msg_and_die("bad IP address '%s'", ip);
  69         return in.s_addr;
  70 }
  71
  72 static struct dev*
  73 find_device(llist_t *iface_list, const char *name)
  74 {
  75         while (iface_list) {
  76                 struct dev *dev = (void*) iface_list->data;
  77                 if (strcmp(dev->name, name) == 0)
  78                         return dev;
  79                 iface_list = iface_list->link;
  80         }
  81         return NULL;
  82 }
  83
  84 static void
  85 set_from_template(struct dev *dev, struct dev *template)
  86 {
  87         if (template->ip_addr != 0)
  88                 dev->ip_addr = template->ip_addr;
  89         if (template->ip_netmask != 0)
  90                 dev->ip_netmask = template->ip_netmask;
  91         if (template->ip_server != 0)
  92                 dev->ip_server = template->ip_server;
  93         if (template->ip_router != 0)
  94                 dev->ip_router = template->ip_router;
  95         dev->fixed = template->fixed;
  96 }
  97
  98 // "ip=PROTO" - also implies -o
  99 // "nfsaddrs=PROTO" - also implies -o
 100 // "<devname>"
 101 // "[ip=/nfsaddrs=]IP:SERVER_IP:ROUTER:NETMASK:HOSTNAME:IFACE:METHOD"
 102 // all optional. trailing empty :: can be skipped, only one : needs to be there
 103 // (to distinguish from other formats).
 104 // ":::::eth0" - dhcp on eth0
 105 // ":" - dhcp on all ifaces
 106 // "::1.2.3.4" - dhcp on all ifaces, gateway is 1.2.3.4 (fairly nonsensical)
 107 static void
 108 add_all_devices(llist_t **iface_list, struct dev *template);
 109 static struct dev*
 110 add_device(llist_t **iface_list, char *ip)
 111 {
 112         struct dev *dev;
 113
 114         dev = xzalloc(sizeof(*dev));
 115         dev->fixed = G.fixed;
 116
 117         if (strncmp("ip=", ip, 3) == 0
 118          || strncmp("nfsaddrs=", ip, 9) == 0
 119         ) {
 120                 int fixed;
 121
 122                 ip = strchr(ip, '=') + 1;
 123                 fixed = parse_method(ip);
 124                 if (fixed >= 0) {
 125                         add_all_devices(iface_list, dev);
 126                         free(dev);
 127                         return NULL;
 128                 }
 129         }
 130
 131         if (!strchr(ip, ':')) {
 132                 dev->name = ip;
 133         } else {
 134                 unsigned opt = 0;
 135                 while (ip && *ip) {
 136                         char *next = strchr(ip, ':');
 137                         if (next)
 138                                 *next++ = '\0';
 139                         if (opt > 6)
 140                                 bb_error_msg_and_die("too many options for %s", dev->name);
 141                         if (ip[0]) switch (opt) {
 142                         case 0:
 143                                 dev->ip_addr = parse_addr(ip);
 144                                 break;
 145                         case 1:
 146                                 dev->ip_server = parse_addr(ip);
 147                                 break;
 148                         case 2:
 149                                 dev->ip_router = parse_addr(ip);
 150                                 break;
 151                         case 3:
 152                                 dev->ip_netmask = parse_addr(ip);
 153                                 break;
 154                         case 4:
 155                                 if (G.hostname && strcmp(G.hostname, ip) != 0)
 156                                         bb_error_msg_and_die("hostname must be the same");
 157                                 G.hostname = ip;
 158                                 break;
 159                         case 5:
 160                                 dev->name = ip;
 161                                 break;
 162                         case 6:
 163                                 dev->fixed = parse_method(ip);
 164                                 break;
 165                         }
 166                         ip = next;
 167                         opt++;
 168                 }
 169         }
 170
 171         if (dev->name == NULL
 172          || strcmp(dev->name, "all") == 0
 173         ) {
 174                 add_all_devices(iface_list, dev);
 175                 free(dev);
 176                 return NULL;
 177         }
 178         llist_add_to_end(iface_list, dev);
 179         return dev;
 180 }
 181
 182 static void
 183 add_all_devices(llist_t **iface_list, struct dev *template)
 184 {
 185         DIR *d;
 186         struct dirent *de;
 187 #define sys_class_net "/sys/class/net"
 188
 189         /* All forms of "config all ifaces" imply -o */
 190         option_mask32 |= 1;
 191
 192         d = opendir(sys_class_net);
 193         if (!d)
 194                 return;
 195
 196         while ((de = readdir(d)) != NULL) {
 197                 struct dev *dev;
 198                 char *filename;
 199                 char p[sizeof(long)*3];
 200                 unsigned long flags;
 201                 int r;
 202
 203                 /* Exclude devices beginning with dots as well as . and .. */
 204                 if (de->d_name[0] == '.')
 205                         continue;
 206                 filename = xasprintf("%s/%s/flags", sys_class_net, de->d_name);
 207                 r = open_read_close(filename, p, sizeof(p) - 1);
 208                 free(filename);
 209                 if (r < 0)
 210                         continue;
 211                 p[r] = '\0';
 212                 /* file's format is "0xNNNN\n" */
 213                 flags = bb_strtoul(p, NULL, 0);
 214                 /*
 215                  * Heuristic for if this is a reasonable boot interface.
 216                  * This is the same logic the in-kernel ipconfig uses.
 217                  */
 218                 if (flags & IFF_LOOPBACK)
 219                         continue;
 220                 if (!(flags & (IFF_BROADCAST | IFF_POINTOPOINT)))
 221                         continue;
 222                 if (find_device(*iface_list, de->d_name))
 223                         continue;
 224                 dev = add_device(iface_list, xstrdup(de->d_name));
 225                 if (dev)
 226                         set_from_template(dev, template);
 227         }
 228         closedir(d);
 229 #undef sys_class_net
 230 }
 231
 232 //usage:#define ipconfig_trivial_usage
 233 //usage:       "[-c METHOD] [-t TIMEOUT] [-on] [-i VENDOR_ID] [-p PORT] [-d] IFACE..."
 234 //usage:#define ipconfig_full_usage "\n\n"
 235 //usage:       "(Auto)configure network"
 236 //usage:   "\n"
 237 //usage:   "\n""        -c METHOD       off/none/static or on/dhcp (default)"
 238 //usage:   "\n""        -t SECONDS      Give up after SECONDS"
 239 //usage:   "\n""        -o              Stop after one interface is configured"
 240 //usage:   "\n""        -n              Dry run"
 241 //usage:   "\n""        -i VENDOR_ID    DHCP vendor id (default '')"
 242 //usage:   "\n""        -p PORT         DHCP port to use"
 243 //usage:   "\n""        [-d] IFACE...   Interface(s)"
 244 //usage:   "\n"
 245 //usage:   "\n""        IFACE can be:"
 246 //usage:   "\n""        all - configure all interfaces"
 247 //usage:   "\n""        IFACE - configure this interface"
 248 //usage:   "\n""        IP:SERVER_IP:ROUTER:NETMASK:HOSTNAME:IFACE:METHOD (all optional)"
 249 // TIMEOUT defaults to infinite
 250 // -d actually is an option with an argument
 251 // (not a clue why klibc-utils has two ways to specify interfaces)
 252 int ipconfig_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 253 int ipconfig_main(int argc UNUSED_PARAM, char **argv)
 254 {
 255         const char *method = "";
 256         const char *vendor_id = "";
 257         llist_t *devname_list = NULL;
 258         llist_t *iface_list;
 259         int timeout = -1;
 260         unsigned port;
 261         unsigned opt;
 262
 263         INIT_G();
 264
 265         opt = getopt32(argv,
 266                 "onc:t:i:p:+d:*",
 267                 &method, &timeout, &vendor_id, &port, &devname_list
 268         );
 269         argv += optind;
 270
 271         G.fixed = parse_method(method);
 272         if (G.fixed < 0)
 273                 bb_show_usage();
 274
 275         iface_list = NULL;
 276         while (devname_list)
 277                 add_device(&iface_list, (char*) llist_pop(&devname_list));
 278         while (*argv)
 279                 add_device(&iface_list, *argv++);
 280
 281         while (iface_list) {
 282                 struct dev *dev = (void*) iface_list->data;
 283                 printf("name:'%s'\n", dev->name);
 284                 printf("fixed:%u\n" , dev->fixed);
 285                 printf("ip:%s/"     , inet_ntoa(*(struct in_addr*)&dev->ip_addr));
 286                 printf("%s\n"       , inet_ntoa(*(struct in_addr*)&dev->ip_netmask));
 287                 printf("server:%s\n", inet_ntoa(*(struct in_addr*)&dev->ip_server));
 288                 printf("router:%s\n", inet_ntoa(*(struct in_addr*)&dev->ip_router));
 289                 iface_list = iface_list->link;
 290         }
 291         bb_error_msg("hostname:'%s'", G.hostname);
 292         bb_error_msg("fixed:%u", G.fixed);
 293
 294         return EXIT_SUCCESS;
 295 }
 296 //After device is configured, write out a "/run/net-IFACE.conf" file:
 297 //                                                              // udchcp env values:
 298 //write_option("DEVICE",        dev->name);                     interface=eth0
 299 //write_option("PROTO",         method);
 300 //write_option("IPV4ADDR",      dev->ip_addr);                  ip=10.43.17.38
 301 //write_option("IPV4BROADCAST", dev->ip_broadcast);             subnet=255.255.255.0 mask=24
 302 //write_option("IPV4NETMASK",   dev->ip_netmask);               subnet=255.255.255.0 mask=24
 303 //write_option("IPV4GATEWAY",   dev->ip_gateway);               router=10.43.17.254
 304 //write_option("IPV4DNS0",      dev->ip_nameserver[0]);         dns=10.38.5.26 10.11.5.19
 305 //write_option("IPV4DNS1",      dev->ip_nameserver[1]);         dns=10.38.5.26 10.11.5.19
 306 //write_option("HOSTNAME",      dev->hostname);                   hostname="STR"
 307 //write_option("DNSDOMAIN",     dev->dnsdomainname);            domain=domain.com
 308 //write_option("NISDOMAIN",     dev->nisdomainname);              nisdomain="STR"
 309 //write_option("ROOTSERVER",    my_inet_ntoa(dev->ip_server));  serverid=10.44.6.2
 310 //write_option("ROOTPATH",      dev->bootpath);                   rootpath="STR"
 311 //write_option("filename",      dev->filename);                 boot_file=/pxelinux.0
 312 //write_option("UPTIME",        dev->uptime);                     sysinfo()->uptime
 313 //write_option("DHCPLEASETIME", dev->dhcpleasetime);            lease=44148
 314 //write_option("DOMAINSEARCH",  dev->domainsearch);             search="ABC DEF"
 315 //
 316 //(write_option writes out single-quote escaped string, VAR='VAL')