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 | SOCK_CLOEXEC, 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 | SOCK_CLOEXEC, 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 | SOCK_CLOEXEC, 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 struct ifreq ifr; 425 ifc_init_ifr(name, &ifr); 426 427 ifr.ifr_hwaddr.sa_family = ARPHRD_ETHER; 428 memcpy(&ifr.ifr_hwaddr.sa_data, ptr, ETH_ALEN); 429 return ioctl(ifc_ctl_sock, SIOCSIFHWADDR, &ifr); 430 } 431 432 int ifc_set_mask(const char *name, in_addr_t mask) 433 { 434 struct ifreq ifr; 435 int ret; 436 437 ifc_init_ifr(name, &ifr); 438 init_sockaddr_in(&ifr.ifr_addr, mask); 439 440 ret = ioctl(ifc_ctl_sock, SIOCSIFNETMASK, &ifr); 441 if (DBG) printerr("ifc_set_mask(%s, xx) = %d", name, ret); 442 return ret; 443 } 444 445 int ifc_set_prefixLength(const char *name, int prefixLength) 446 { 447 struct ifreq ifr; 448 // TODO - support ipv6 449 if (prefixLength > 32 || prefixLength < 0) return -1; 450 451 in_addr_t mask = prefixLengthToIpv4Netmask(prefixLength); 452 ifc_init_ifr(name, &ifr); 453 init_sockaddr_in(&ifr.ifr_addr, mask); 454 455 return ioctl(ifc_ctl_sock, SIOCSIFNETMASK, &ifr); 456 } 457 458 int ifc_get_addr(const char *name, in_addr_t *addr) 459 { 460 struct ifreq ifr; 461 int ret = 0; 462 463 ifc_init_ifr(name, &ifr); 464 if (addr != NULL) { 465 ret = ioctl(ifc_ctl_sock, SIOCGIFADDR, &ifr); 466 if (ret < 0) { 467 *addr = 0; 468 } else { 469 *addr = ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr; 470 } 471 } 472 return ret; 473 } 474 475 int ifc_get_info(const char *name, in_addr_t *addr, int *prefixLength, unsigned *flags) 476 { 477 struct ifreq ifr; 478 ifc_init_ifr(name, &ifr); 479 480 if (addr != NULL) { 481 if(ioctl(ifc_ctl_sock, SIOCGIFADDR, &ifr) < 0) { 482 *addr = 0; 483 } else { 484 *addr = ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr; 485 } 486 } 487 488 if (prefixLength != NULL) { 489 if(ioctl(ifc_ctl_sock, SIOCGIFNETMASK, &ifr) < 0) { 490 *prefixLength = 0; 491 } else { 492 *prefixLength = ipv4NetmaskToPrefixLength( 493 ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr); 494 } 495 } 496 497 if (flags != NULL) { 498 if(ioctl(ifc_ctl_sock, SIOCGIFFLAGS, &ifr) < 0) { 499 *flags = 0; 500 } else { 501 *flags = ifr.ifr_flags; 502 } 503 } 504 505 return 0; 506 } 507 508 int ifc_act_on_ipv4_route(int action, const char *ifname, struct in_addr dst, int prefix_length, 509 struct in_addr gw) 510 { 511 struct rtentry rt; 512 int result; 513 in_addr_t netmask; 514 515 memset(&rt, 0, sizeof(rt)); 516 517 rt.rt_dst.sa_family = AF_INET; 518 rt.rt_dev = (void*) ifname; 519 520 netmask = prefixLengthToIpv4Netmask(prefix_length); 521 init_sockaddr_in(&rt.rt_genmask, netmask); 522 init_sockaddr_in(&rt.rt_dst, dst.s_addr); 523 rt.rt_flags = RTF_UP; 524 525 if (prefix_length == 32) { 526 rt.rt_flags |= RTF_HOST; 527 } 528 529 if (gw.s_addr != 0) { 530 rt.rt_flags |= RTF_GATEWAY; 531 init_sockaddr_in(&rt.rt_gateway, gw.s_addr); 532 } 533 534 ifc_init(); 535 536 if (ifc_ctl_sock < 0) { 537 return -errno; 538 } 539 540 result = ioctl(ifc_ctl_sock, action, &rt); 541 if (result < 0) { 542 if (errno == EEXIST) { 543 result = 0; 544 } else { 545 result = -errno; 546 } 547 } 548 ifc_close(); 549 return result; 550 } 551 552 /* deprecated - v4 only */ 553 int ifc_create_default_route(const char *name, in_addr_t gw) 554 { 555 struct in_addr in_dst, in_gw; 556 557 in_dst.s_addr = 0; 558 in_gw.s_addr = gw; 559 560 int ret = ifc_act_on_ipv4_route(SIOCADDRT, name, in_dst, 0, in_gw); 561 if (DBG) printerr("ifc_create_default_route(%s, %d) = %d", name, gw, ret); 562 return ret; 563 } 564 565 // Needed by code in hidden partner repositories / branches, so don't delete. 566 int ifc_enable(const char *ifname) 567 { 568 int result; 569 570 ifc_init(); 571 result = ifc_up(ifname); 572 ifc_close(); 573 return result; 574 } 575 576 // Needed by code in hidden partner repositories / branches, so don't delete. 577 int ifc_disable(const char *ifname) 578 { 579 unsigned addr, count; 580 int result; 581 582 ifc_init(); 583 result = ifc_down(ifname); 584 585 ifc_set_addr(ifname, 0); 586 for (count=0, addr=1;((addr != 0) && (count < 255)); count++) { 587 if (ifc_get_addr(ifname, &addr) < 0) 588 break; 589 if (addr) 590 ifc_set_addr(ifname, 0); 591 } 592 593 ifc_close(); 594 return result; 595 } 596 597 int ifc_reset_connections(const char *ifname, const int reset_mask) 598 { 599 #ifdef HAVE_ANDROID_OS 600 int result, success; 601 in_addr_t myaddr = 0; 602 struct ifreq ifr; 603 struct in6_ifreq ifr6; 604 605 if (reset_mask & RESET_IPV4_ADDRESSES) { 606 /* IPv4. Clear connections on the IP address. */ 607 ifc_init(); 608 if (!(reset_mask & RESET_IGNORE_INTERFACE_ADDRESS)) { 609 ifc_get_info(ifname, &myaddr, NULL, NULL); 610 } 611 ifc_init_ifr(ifname, &ifr); 612 init_sockaddr_in(&ifr.ifr_addr, myaddr); 613 result = ioctl(ifc_ctl_sock, SIOCKILLADDR, &ifr); 614 ifc_close(); 615 } else { 616 result = 0; 617 } 618 619 if (reset_mask & RESET_IPV6_ADDRESSES) { 620 /* 621 * IPv6. On Linux, when an interface goes down it loses all its IPv6 622 * addresses, so we don't know which connections belonged to that interface 623 * So we clear all unused IPv6 connections on the device by specifying an 624 * empty IPv6 address. 625 */ 626 ifc_init6(); 627 // This implicitly specifies an address of ::, i.e., kill all IPv6 sockets. 628 memset(&ifr6, 0, sizeof(ifr6)); 629 success = ioctl(ifc_ctl_sock6, SIOCKILLADDR, &ifr6); 630 if (result == 0) { 631 result = success; 632 } 633 ifc_close6(); 634 } 635 636 return result; 637 #else 638 return 0; 639 #endif 640 } 641 642 /* 643 * Removes the default route for the named interface. 644 */ 645 int ifc_remove_default_route(const char *ifname) 646 { 647 struct rtentry rt; 648 int result; 649 650 ifc_init(); 651 memset(&rt, 0, sizeof(rt)); 652 rt.rt_dev = (void *)ifname; 653 rt.rt_flags = RTF_UP|RTF_GATEWAY; 654 init_sockaddr_in(&rt.rt_dst, 0); 655 if ((result = ioctl(ifc_ctl_sock, SIOCDELRT, &rt)) < 0) { 656 ALOGD("failed to remove default route for %s: %s", ifname, strerror(errno)); 657 } 658 ifc_close(); 659 return result; 660 } 661 662 int 663 ifc_configure(const char *ifname, 664 in_addr_t address, 665 uint32_t prefixLength, 666 in_addr_t gateway, 667 in_addr_t dns1, 668 in_addr_t dns2) { 669 670 char dns_prop_name[PROPERTY_KEY_MAX]; 671 672 ifc_init(); 673 674 if (ifc_up(ifname)) { 675 printerr("failed to turn on interface %s: %s\n", ifname, strerror(errno)); 676 ifc_close(); 677 return -1; 678 } 679 if (ifc_set_addr(ifname, address)) { 680 printerr("failed to set ipaddr %s: %s\n", ipaddr_to_string(address), strerror(errno)); 681 ifc_close(); 682 return -1; 683 } 684 if (ifc_set_prefixLength(ifname, prefixLength)) { 685 printerr("failed to set prefixLength %d: %s\n", prefixLength, strerror(errno)); 686 ifc_close(); 687 return -1; 688 } 689 if (ifc_create_default_route(ifname, gateway)) { 690 printerr("failed to set default route %s: %s\n", ipaddr_to_string(gateway), strerror(errno)); 691 ifc_close(); 692 return -1; 693 } 694 695 ifc_close(); 696 697 snprintf(dns_prop_name, sizeof(dns_prop_name), "net.%s.dns1", ifname); 698 property_set(dns_prop_name, dns1 ? ipaddr_to_string(dns1) : ""); 699 snprintf(dns_prop_name, sizeof(dns_prop_name), "net.%s.dns2", ifname); 700 property_set(dns_prop_name, dns2 ? ipaddr_to_string(dns2) : ""); 701 702 return 0; 703 } 704
