1 /* 2 * Copyright 2008, The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <stdio.h> 18 #include <stdlib.h> 19 #include <unistd.h> 20 #include <string.h> 21 #include <errno.h> 22 23 #include <sys/socket.h> 24 #include <sys/select.h> 25 #include <sys/types.h> 26 #include <netinet/in.h> 27 #include <arpa/inet.h> 28 #include <net/if.h> 29 #include <netdb.h> 30 31 #include <linux/if.h> 32 #include <linux/if_ether.h> 33 #include <linux/if_arp.h> 34 #include <linux/netlink.h> 35 #include <linux/route.h> 36 #include <linux/ipv6_route.h> 37 #include <linux/rtnetlink.h> 38 #include <linux/sockios.h> 39 40 #include "netutils/ifc.h" 41 42 #ifdef ANDROID 43 #define LOG_TAG "NetUtils" 44 #include <cutils/log.h> 45 #include <cutils/properties.h> 46 #else 47 #include <stdio.h> 48 #include <string.h> 49 #define ALOGD printf 50 #define ALOGW printf 51 #endif 52 53 #ifdef HAVE_ANDROID_OS 54 /* SIOCKILLADDR is an Android extension. */ 55 #define SIOCKILLADDR 0x8939 56 #endif 57 58 static int ifc_ctl_sock = -1; 59 static int ifc_ctl_sock6 = -1; 60 void printerr(char *fmt, ...); 61 62 #define DBG 0 63 #define INET_ADDRLEN 4 64 #define INET6_ADDRLEN 16 65 66 in_addr_t prefixLengthToIpv4Netmask(int prefix_length) 67 { 68 in_addr_t mask = 0; 69 70 // C99 (6.5.7): shifts of 32 bits have undefined results 71 if (prefix_length <= 0 || prefix_length > 32) { 72 return 0; 73 } 74 75 mask = ~mask << (32 - prefix_length); 76 mask = htonl(mask); 77 78 return mask; 79 } 80 81 int ipv4NetmaskToPrefixLength(in_addr_t mask) 82 { 83 int prefixLength = 0; 84 uint32_t m = (uint32_t)ntohl(mask); 85 while (m & 0x80000000) { 86 prefixLength++; 87 m = m << 1; 88 } 89 return prefixLength; 90 } 91 92 static const char *ipaddr_to_string(in_addr_t addr) 93 { 94 struct in_addr in_addr; 95 96 in_addr.s_addr = addr; 97 return inet_ntoa(in_addr); 98 } 99 100 int string_to_ip(const char *string, struct sockaddr_storage *ss) { 101 struct addrinfo hints, *ai; 102 int ret; 103 104 if (ss == NULL) { 105 return -EFAULT; 106 } 107 108 memset(&hints, 0, sizeof(hints)); 109 hints.ai_family = AF_UNSPEC; 110 hints.ai_flags = AI_NUMERICHOST; 111 hints.ai_socktype = SOCK_DGRAM; 112 113 ret = getaddrinfo(string, NULL, &hints, &ai); 114 if (ret == 0) { 115 memcpy(ss, ai->ai_addr, ai->ai_addrlen); 116 freeaddrinfo(ai); 117 } 118 119 return ret; 120 } 121 122 int ifc_init(void) 123 { 124 int ret; 125 if (ifc_ctl_sock == -1) { 126 ifc_ctl_sock = socket(AF_INET, SOCK_DGRAM, 0); 127 if (ifc_ctl_sock < 0) { 128 printerr("socket() failed: %s\n", strerror(errno)); 129 } 130 } 131 132 ret = ifc_ctl_sock < 0 ? -1 : 0; 133 if (DBG) printerr("ifc_init_returning %d", ret); 134 return ret; 135 } 136 137 int ifc_init6(void) 138 { 139 if (ifc_ctl_sock6 == -1) { 140 ifc_ctl_sock6 = socket(AF_INET6, SOCK_DGRAM, 0); 141 if (ifc_ctl_sock6 < 0) { 142 printerr("socket() failed: %s\n", strerror(errno)); 143 } 144 } 145 return ifc_ctl_sock6 < 0 ? -1 : 0; 146 } 147 148 void ifc_close(void) 149 { 150 if (DBG) printerr("ifc_close"); 151 if (ifc_ctl_sock != -1) { 152 (void)close(ifc_ctl_sock); 153 ifc_ctl_sock = -1; 154 } 155 } 156 157 void ifc_close6(void) 158 { 159 if (ifc_ctl_sock6 != -1) { 160 (void)close(ifc_ctl_sock6); 161 ifc_ctl_sock6 = -1; 162 } 163 } 164 165 static void ifc_init_ifr(const char *name, struct ifreq *ifr) 166 { 167 memset(ifr, 0, sizeof(struct ifreq)); 168 strncpy(ifr->ifr_name, name, IFNAMSIZ); 169 ifr->ifr_name[IFNAMSIZ - 1] = 0; 170 } 171 172 int ifc_get_hwaddr(const char *name, void *ptr) 173 { 174 int r; 175 struct ifreq ifr; 176 ifc_init_ifr(name, &ifr); 177 178 r = ioctl(ifc_ctl_sock, SIOCGIFHWADDR, &ifr); 179 if(r < 0) return -1; 180 181 memcpy(ptr, &ifr.ifr_hwaddr.sa_data, ETH_ALEN); 182 return 0; 183 } 184 185 int ifc_get_ifindex(const char *name, int *if_indexp) 186 { 187 int r; 188 struct ifreq ifr; 189 ifc_init_ifr(name, &ifr); 190 191 r = ioctl(ifc_ctl_sock, SIOCGIFINDEX, &ifr); 192 if(r < 0) return -1; 193 194 *if_indexp = ifr.ifr_ifindex; 195 return 0; 196 } 197 198 static int ifc_set_flags(const char *name, unsigned set, unsigned clr) 199 { 200 struct ifreq ifr; 201 ifc_init_ifr(name, &ifr); 202 203 if(ioctl(ifc_ctl_sock, SIOCGIFFLAGS, &ifr) < 0) return -1; 204 ifr.ifr_flags = (ifr.ifr_flags & (~clr)) | set; 205 return ioctl(ifc_ctl_sock, SIOCSIFFLAGS, &ifr); 206 } 207 208 int ifc_up(const char *name) 209 { 210 int ret = ifc_set_flags(name, IFF_UP, 0); 211 if (DBG) printerr("ifc_up(%s) = %d", name, ret); 212 return ret; 213 } 214 215 int ifc_down(const char *name) 216 { 217 int ret = ifc_set_flags(name, 0, IFF_UP); 218 if (DBG) printerr("ifc_down(%s) = %d", name, ret); 219 return ret; 220 } 221 222 static void init_sockaddr_in(struct sockaddr *sa, in_addr_t addr) 223 { 224 struct sockaddr_in *sin = (struct sockaddr_in *) sa; 225 sin->sin_family = AF_INET; 226 sin->sin_port = 0; 227 sin->sin_addr.s_addr = addr; 228 } 229 230 int ifc_set_addr(const char *name, in_addr_t addr) 231 { 232 struct ifreq ifr; 233 int ret; 234 235 ifc_init_ifr(name, &ifr); 236 init_sockaddr_in(&ifr.ifr_addr, addr); 237 238 ret = ioctl(ifc_ctl_sock, SIOCSIFADDR, &ifr); 239 if (DBG) printerr("ifc_set_addr(%s, xx) = %d", name, ret); 240 return ret; 241 } 242 243 /* 244 * Adds or deletes an IP address on an interface. 245 * 246 * Action is one of: 247 * - RTM_NEWADDR (to add a new address) 248 * - RTM_DELADDR (to delete an existing address) 249 * 250 * Returns zero on success and negative errno on failure. 251 */ 252 int ifc_act_on_address(int action, const char *name, const char *address, 253 int prefixlen) { 254 int ifindex, s, len, ret; 255 struct sockaddr_storage ss; 256 void *addr; 257 size_t addrlen; 258 struct { 259 struct nlmsghdr n; 260 struct ifaddrmsg r; 261 // Allow for IPv6 address, headers, and padding. 262 char attrbuf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) + 263 NLMSG_ALIGN(sizeof(struct rtattr)) + 264 NLMSG_ALIGN(INET6_ADDRLEN)]; 265 } req; 266 struct rtattr *rta; 267 struct nlmsghdr *nh; 268 struct nlmsgerr *err; 269 char buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) + 270 NLMSG_ALIGN(sizeof(struct nlmsgerr)) + 271 NLMSG_ALIGN(sizeof(struct nlmsghdr))]; 272 273 // Get interface ID. 274 ifindex = if_nametoindex(name); 275 if (ifindex == 0) { 276 return -errno; 277 } 278 279 // Convert string representation to sockaddr_storage. 280 ret = string_to_ip(address, &ss); 281 if (ret) { 282 return ret; 283 } 284 285 // Determine address type and length. 286 if (ss.ss_family == AF_INET) { 287 struct sockaddr_in *sin = (struct sockaddr_in *) &ss; 288 addr = &sin->sin_addr; 289 addrlen = INET_ADDRLEN; 290 } else if (ss.ss_family == AF_INET6) { 291 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &ss; 292 addr = &sin6->sin6_addr; 293 addrlen = INET6_ADDRLEN; 294 } else { 295 return -EAFNOSUPPORT; 296 } 297 298 // Fill in netlink structures. 299 memset(&req, 0, sizeof(req)); 300 301 // Netlink message header. 302 req.n.nlmsg_len = NLMSG_LENGTH(sizeof(req.r)); 303 req.n.nlmsg_type = action; 304 req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; 305 req.n.nlmsg_pid = getpid(); 306 307 // Interface address message header. 308 req.r.ifa_family = ss.ss_family; 309 req.r.ifa_prefixlen = prefixlen; 310 req.r.ifa_index = ifindex; 311 312 // Routing attribute. Contains the actual IP address. 313 rta = (struct rtattr *) (((char *) &req) + NLMSG_ALIGN(req.n.nlmsg_len)); 314 rta->rta_type = IFA_LOCAL; 315 rta->rta_len = RTA_LENGTH(addrlen); 316 req.n.nlmsg_len = NLMSG_ALIGN(req.n.nlmsg_len) + RTA_LENGTH(addrlen); 317 memcpy(RTA_DATA(rta), addr, addrlen); 318 319 s = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE); 320 if (send(s, &req, req.n.nlmsg_len, 0) < 0) { 321 close(s); 322 return -errno; 323 } 324 325 len = recv(s, buf, sizeof(buf), 0); 326 close(s); 327 if (len < 0) { 328 return -errno; 329 } 330 331 // Parse the acknowledgement to find the return code. 332 nh = (struct nlmsghdr *) buf; 333 if (!NLMSG_OK(nh, (unsigned) len) || nh->nlmsg_type != NLMSG_ERROR) { 334 return -EINVAL; 335 } 336 err = NLMSG_DATA(nh); 337 338 // Return code is negative errno. 339 return err->error; 340 } 341 342 int ifc_add_address(const char *name, const char *address, int prefixlen) { 343 return ifc_act_on_address(RTM_NEWADDR, name, address, prefixlen); 344 } 345 346 int ifc_del_address(const char *name, const char * address, int prefixlen) { 347 return ifc_act_on_address(RTM_DELADDR, name, address, prefixlen); 348 } 349 350 /* 351 * Clears IPv6 addresses on the specified interface. 352 */ 353 int ifc_clear_ipv6_addresses(const char *name) { 354 char rawaddrstr[INET6_ADDRSTRLEN], addrstr[INET6_ADDRSTRLEN]; 355 unsigned int prefixlen; 356 int lasterror = 0, i, j, ret; 357 char ifname[64]; // Currently, IFNAMSIZ = 16. 358 FILE *f = fopen("/proc/net/if_inet6", "r"); 359 if (!f) { 360 return -errno; 361 } 362 363 // Format: 364 // 20010db8000a0001fc446aa4b5b347ed 03 40 00 01 wlan0 365 while (fscanf(f, "%32s %*02x %02x %*02x %*02x %63s\n", 366 rawaddrstr, &prefixlen, ifname) == 3) { 367 // Is this the interface we're looking for? 368 if (strcmp(name, ifname)) { 369 continue; 370 } 371 372 // Put the colons back into the address. 373 for (i = 0, j = 0; i < 32; i++, j++) { 374 addrstr[j] = rawaddrstr[i]; 375 if (i % 4 == 3) { 376 addrstr[++j] = ':'; 377 } 378 } 379 addrstr[j - 1] = '\0'; 380 381 // Don't delete the link-local address as well, or it will disable IPv6 382 // on the interface. 383 if (strncmp(addrstr, "fe80:", 5) == 0) { 384 continue; 385 } 386 387 ret = ifc_del_address(ifname, addrstr, prefixlen); 388 if (ret) { 389 ALOGE("Deleting address %s/%d on %s: %s", addrstr, prefixlen, ifname, 390 strerror(-ret)); 391 lasterror = ret; 392 } 393 } 394 395 fclose(f); 396 return lasterror; 397 } 398 399 /* 400 * Clears IPv4 addresses on the specified interface. 401 */ 402 void ifc_clear_ipv4_addresses(const char *name) { 403 unsigned count, addr; 404 ifc_init(); 405 for (count=0, addr=1;((addr != 0) && (count < 255)); count++) { 406 if (ifc_get_addr(name, &addr) < 0) 407 break; 408 if (addr) 409 ifc_set_addr(name, 0); 410 } 411 ifc_close(); 412 } 413 414 /* 415 * Clears all IP addresses on the specified interface. 416 */ 417 int ifc_clear_addresses(const char *name) { 418 ifc_clear_ipv4_addresses(name); 419 return ifc_clear_ipv6_addresses(name); 420 } 421 422 int ifc_set_hwaddr(const char *name, const void *ptr) 423 { 424 int r; 425 struct ifreq ifr; 426 ifc_init_ifr(name, &ifr); 427 428 ifr.ifr_hwaddr.sa_family = ARPHRD_ETHER; 429 memcpy(&ifr.ifr_hwaddr.sa_data, ptr, ETH_ALEN); 430 return ioctl(ifc_ctl_sock, SIOCSIFHWADDR, &ifr); 431 } 432 433 int ifc_set_mask(const char *name, in_addr_t mask) 434 { 435 struct ifreq ifr; 436 int ret; 437 438 ifc_init_ifr(name, &ifr); 439 init_sockaddr_in(&ifr.ifr_addr, mask); 440 441 ret = ioctl(ifc_ctl_sock, SIOCSIFNETMASK, &ifr); 442 if (DBG) printerr("ifc_set_mask(%s, xx) = %d", name, ret); 443 return ret; 444 } 445 446 int ifc_set_prefixLength(const char *name, int prefixLength) 447 { 448 struct ifreq ifr; 449 // TODO - support ipv6 450 if (prefixLength > 32 || prefixLength < 0) return -1; 451 452 in_addr_t mask = prefixLengthToIpv4Netmask(prefixLength); 453 ifc_init_ifr(name, &ifr); 454 init_sockaddr_in(&ifr.ifr_addr, mask); 455 456 return ioctl(ifc_ctl_sock, SIOCSIFNETMASK, &ifr); 457 } 458 459 int ifc_get_addr(const char *name, in_addr_t *addr) 460 { 461 struct ifreq ifr; 462 int ret = 0; 463 464 ifc_init_ifr(name, &ifr); 465 if (addr != NULL) { 466 ret = ioctl(ifc_ctl_sock, SIOCGIFADDR, &ifr); 467 if (ret < 0) { 468 *addr = 0; 469 } else { 470 *addr = ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr; 471 } 472 } 473 return ret; 474 } 475 476 int ifc_get_info(const char *name, in_addr_t *addr, int *prefixLength, unsigned *flags) 477 { 478 struct ifreq ifr; 479 ifc_init_ifr(name, &ifr); 480 481 if (addr != NULL) { 482 if(ioctl(ifc_ctl_sock, SIOCGIFADDR, &ifr) < 0) { 483 *addr = 0; 484 } else { 485 *addr = ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr; 486 } 487 } 488 489 if (prefixLength != NULL) { 490 if(ioctl(ifc_ctl_sock, SIOCGIFNETMASK, &ifr) < 0) { 491 *prefixLength = 0; 492 } else { 493 *prefixLength = ipv4NetmaskToPrefixLength( 494 ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr); 495 } 496 } 497 498 if (flags != NULL) { 499 if(ioctl(ifc_ctl_sock, SIOCGIFFLAGS, &ifr) < 0) { 500 *flags = 0; 501 } else { 502 *flags = ifr.ifr_flags; 503 } 504 } 505 506 return 0; 507 } 508 509 int ifc_act_on_ipv4_route(int action, const char *ifname, struct in_addr dst, int prefix_length, 510 struct in_addr gw) 511 { 512 struct rtentry rt; 513 int result; 514 in_addr_t netmask; 515 516 memset(&rt, 0, sizeof(rt)); 517 518 rt.rt_dst.sa_family = AF_INET; 519 rt.rt_dev = (void*) ifname; 520 521 netmask = prefixLengthToIpv4Netmask(prefix_length); 522 init_sockaddr_in(&rt.rt_genmask, netmask); 523 init_sockaddr_in(&rt.rt_dst, dst.s_addr); 524 rt.rt_flags = RTF_UP; 525 526 if (prefix_length == 32) { 527 rt.rt_flags |= RTF_HOST; 528 } 529 530 if (gw.s_addr != 0) { 531 rt.rt_flags |= RTF_GATEWAY; 532 init_sockaddr_in(&rt.rt_gateway, gw.s_addr); 533 } 534 535 ifc_init(); 536 537 if (ifc_ctl_sock < 0) { 538 return -errno; 539 } 540 541 result = ioctl(ifc_ctl_sock, action, &rt); 542 if (result < 0) { 543 if (errno == EEXIST) { 544 result = 0; 545 } else { 546 result = -errno; 547 } 548 } 549 ifc_close(); 550 return result; 551 } 552 553 /* deprecated - v4 only */ 554 int ifc_create_default_route(const char *name, in_addr_t gw) 555 { 556 struct in_addr in_dst, in_gw; 557 558 in_dst.s_addr = 0; 559 in_gw.s_addr = gw; 560 561 int ret = ifc_act_on_ipv4_route(SIOCADDRT, name, in_dst, 0, in_gw); 562 if (DBG) printerr("ifc_create_default_route(%s, %d) = %d", name, gw, ret); 563 return ret; 564 } 565 566 // Needed by code in hidden partner repositories / branches, so don't delete. 567 int ifc_enable(const char *ifname) 568 { 569 int result; 570 571 ifc_init(); 572 result = ifc_up(ifname); 573 ifc_close(); 574 return result; 575 } 576 577 // Needed by code in hidden partner repositories / branches, so don't delete. 578 int ifc_disable(const char *ifname) 579 { 580 unsigned addr, count; 581 int result; 582 583 ifc_init(); 584 result = ifc_down(ifname); 585 586 ifc_set_addr(ifname, 0); 587 for (count=0, addr=1;((addr != 0) && (count < 255)); count++) { 588 if (ifc_get_addr(ifname, &addr) < 0) 589 break; 590 if (addr) 591 ifc_set_addr(ifname, 0); 592 } 593 594 ifc_close(); 595 return result; 596 } 597 598 int ifc_reset_connections(const char *ifname, const int reset_mask) 599 { 600 #ifdef HAVE_ANDROID_OS 601 int result, success; 602 in_addr_t myaddr = 0; 603 struct ifreq ifr; 604 struct in6_ifreq ifr6; 605 606 if (reset_mask & RESET_IPV4_ADDRESSES) { 607 /* IPv4. Clear connections on the IP address. */ 608 ifc_init(); 609 if (!(reset_mask & RESET_IGNORE_INTERFACE_ADDRESS)) { 610 ifc_get_info(ifname, &myaddr, NULL, NULL); 611 } 612 ifc_init_ifr(ifname, &ifr); 613 init_sockaddr_in(&ifr.ifr_addr, myaddr); 614 result = ioctl(ifc_ctl_sock, SIOCKILLADDR, &ifr); 615 ifc_close(); 616 } else { 617 result = 0; 618 } 619 620 if (reset_mask & RESET_IPV6_ADDRESSES) { 621 /* 622 * IPv6. On Linux, when an interface goes down it loses all its IPv6 623 * addresses, so we don't know which connections belonged to that interface 624 * So we clear all unused IPv6 connections on the device by specifying an 625 * empty IPv6 address. 626 */ 627 ifc_init6(); 628 // This implicitly specifies an address of ::, i.e., kill all IPv6 sockets. 629 memset(&ifr6, 0, sizeof(ifr6)); 630 success = ioctl(ifc_ctl_sock6, SIOCKILLADDR, &ifr6); 631 if (result == 0) { 632 result = success; 633 } 634 ifc_close6(); 635 } 636 637 return result; 638 #else 639 return 0; 640 #endif 641 } 642 643 /* 644 * Removes the default route for the named interface. 645 */ 646 int ifc_remove_default_route(const char *ifname) 647 { 648 struct rtentry rt; 649 int result; 650 651 ifc_init(); 652 memset(&rt, 0, sizeof(rt)); 653 rt.rt_dev = (void *)ifname; 654 rt.rt_flags = RTF_UP|RTF_GATEWAY; 655 init_sockaddr_in(&rt.rt_dst, 0); 656 if ((result = ioctl(ifc_ctl_sock, SIOCDELRT, &rt)) < 0) { 657 ALOGD("failed to remove default route for %s: %s", ifname, strerror(errno)); 658 } 659 ifc_close(); 660 return result; 661 } 662 663 int 664 ifc_configure(const char *ifname, 665 in_addr_t address, 666 uint32_t prefixLength, 667 in_addr_t gateway, 668 in_addr_t dns1, 669 in_addr_t dns2) { 670 671 char dns_prop_name[PROPERTY_KEY_MAX]; 672 673 ifc_init(); 674 675 if (ifc_up(ifname)) { 676 printerr("failed to turn on interface %s: %s\n", ifname, strerror(errno)); 677 ifc_close(); 678 return -1; 679 } 680 if (ifc_set_addr(ifname, address)) { 681 printerr("failed to set ipaddr %s: %s\n", ipaddr_to_string(address), strerror(errno)); 682 ifc_close(); 683 return -1; 684 } 685 if (ifc_set_prefixLength(ifname, prefixLength)) { 686 printerr("failed to set prefixLength %d: %s\n", prefixLength, strerror(errno)); 687 ifc_close(); 688 return -1; 689 } 690 if (ifc_create_default_route(ifname, gateway)) { 691 printerr("failed to set default route %s: %s\n", ipaddr_to_string(gateway), strerror(errno)); 692 ifc_close(); 693 return -1; 694 } 695 696 ifc_close(); 697 698 snprintf(dns_prop_name, sizeof(dns_prop_name), "net.%s.dns1", ifname); 699 property_set(dns_prop_name, dns1 ? ipaddr_to_string(dns1) : ""); 700 snprintf(dns_prop_name, sizeof(dns_prop_name), "net.%s.dns2", ifname); 701 property_set(dns_prop_name, dns2 ? ipaddr_to_string(dns2) : ""); 702 703 return 0; 704 } 705
