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ETHInterface_linux.c 9.1 KB

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  1. /* vim: set expandtab ts=4 sw=4: */
  2. /*
  3. * You may redistribute this program and/or modify it under the terms of
  4. * the GNU General Public License as published by the Free Software Foundation,
  5. * either version 3 of the License, or (at your option) any later version.
  6. *
  7. * This program is distributed in the hope that it will be useful,
  8. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  10. * GNU General Public License for more details.
  11. *
  12. * You should have received a copy of the GNU General Public License
  13. * along with this program. If not, see <http://www.gnu.org/licenses/>.
  14. */
  15. #include "interface/ETHInterface.h"
  16. #include "exception/Except.h"
  17. #include "memory/Allocator.h"
  18. #include "net/InterfaceController.h"
  19. #include "wire/Headers.h"
  20. #include "wire/Message.h"
  21. #include "wire/Error.h"
  22. #include "wire/Ethernet.h"
  23. #include "util/Assert.h"
  24. #include "util/platform/Socket.h"
  25. #include "util/events/Event.h"
  26. #include "util/Identity.h"
  27. #include "util/AddrTools.h"
  28. #include "util/version/Version.h"
  29. #include "util/events/Timeout.h"
  30. #include <string.h>
  31. #include <sys/socket.h>
  32. #include <linux/if_packet.h>
  33. #include <linux/if_ether.h>
  34. #include <linux/if_arp.h>
  35. #include <sys/types.h>
  36. #include <sys/ioctl.h>
  37. #include <unistd.h>
  38. #include <errno.h>
  39. #ifndef android
  40. #include <ifaddrs.h>
  41. #endif
  42. #define MAX_PACKET_SIZE 1496
  43. #define MIN_PACKET_SIZE 46
  44. #define PADDING 512
  45. // 2 last 0x00 of .sll_addr are removed from original size (20)
  46. #define SOCKADDR_LL_LEN 18
  47. struct ETHInterface_pvt
  48. {
  49. struct ETHInterface pub;
  50. Socket socket;
  51. /** The unix interface index which is used to identify the eth device. */
  52. int ifindex;
  53. struct Log* logger;
  54. struct sockaddr_ll addrBase;
  55. String* ifName;
  56. Identity
  57. };
  58. static void sendMessageInternal(struct Message* message,
  59. struct sockaddr_ll* addr,
  60. struct ETHInterface_pvt* context)
  61. {
  62. /* Cut down on the noise
  63. uint8_t buff[sizeof(*addr) * 2 + 1] = {0};
  64. Hex_encode(buff, sizeof(buff), (uint8_t*)addr, sizeof(*addr));
  65. Log_debug(context->logger, "Sending ethernet frame to [%s]", buff);
  66. */
  67. if (sendto(context->socket,
  68. message->bytes,
  69. message->length,
  70. 0,
  71. (struct sockaddr*) addr,
  72. sizeof(struct sockaddr_ll)) < 0)
  73. {
  74. switch (errno) {
  75. default:;
  76. Log_info(context->logger, "[%s] Got error sending to socket [%s]",
  77. context->ifName->bytes, strerror(errno));
  78. case EMSGSIZE:
  79. case ENOBUFS:
  80. case EAGAIN:;
  81. // todo: care
  82. }
  83. }
  84. return;
  85. }
  86. static Iface_DEFUN sendMessage(struct Message* msg, struct Iface* iface)
  87. {
  88. struct ETHInterface_pvt* ctx =
  89. Identity_containerOf(iface, struct ETHInterface_pvt, pub.generic.iface);
  90. struct Sockaddr* sa = (struct Sockaddr*) msg->bytes;
  91. Assert_true(msg->length >= Sockaddr_OVERHEAD);
  92. Assert_true(sa->addrLen <= ETHInterface_Sockaddr_SIZE);
  93. struct ETHInterface_Sockaddr sockaddr = { .generic = { .addrLen = 0 } };
  94. Message_pop(msg, &sockaddr, sa->addrLen, NULL);
  95. struct sockaddr_ll addr;
  96. Bits_memcpyConst(&addr, &ctx->addrBase, sizeof(struct sockaddr_ll));
  97. if (sockaddr.generic.flags & Sockaddr_flags_BCAST) {
  98. Bits_memset(addr.sll_addr, 0xff, 6);
  99. } else {
  100. Bits_memcpyConst(addr.sll_addr, sockaddr.mac, 6);
  101. }
  102. struct ETHInterface_Header hdr = {
  103. .version = ETHInterface_CURRENT_VERSION,
  104. .zero = 0,
  105. .length_be = Endian_hostToBigEndian16(msg->length + ETHInterface_Header_SIZE),
  106. .fc00_be = Endian_hostToBigEndian16(0xfc00)
  107. };
  108. Message_push(msg, &hdr, ETHInterface_Header_SIZE, NULL);
  109. sendMessageInternal(msg, &addr, ctx);
  110. return NULL;
  111. }
  112. static void handleEvent2(struct ETHInterface_pvt* context, struct Allocator* messageAlloc)
  113. {
  114. struct Message* msg = Message_new(MAX_PACKET_SIZE, PADDING, messageAlloc);
  115. struct sockaddr_ll addr;
  116. uint32_t addrLen = sizeof(struct sockaddr_ll);
  117. // Knock it out of alignment by 2 bytes so that it will be
  118. // aligned when the idAndPadding is shifted off.
  119. Message_shift(msg, 2, NULL);
  120. int rc = recvfrom(context->socket,
  121. msg->bytes,
  122. msg->length,
  123. 0,
  124. (struct sockaddr*) &addr,
  125. &addrLen);
  126. if (rc < ETHInterface_Header_SIZE) {
  127. Log_debug(context->logger, "Failed to receive eth frame");
  128. return;
  129. }
  130. Assert_true(msg->length >= rc);
  131. msg->length = rc;
  132. //Assert_true(addrLen == SOCKADDR_LL_LEN);
  133. struct ETHInterface_Header hdr;
  134. Message_pop(msg, &hdr, ETHInterface_Header_SIZE, NULL);
  135. // here we could put a switch statement to handle different versions differently.
  136. if (hdr.version != ETHInterface_CURRENT_VERSION) {
  137. Log_debug(context->logger, "DROP unknown version");
  138. return;
  139. }
  140. uint16_t reportedLength = Endian_bigEndianToHost16(hdr.length_be);
  141. reportedLength -= ETHInterface_Header_SIZE;
  142. if (msg->length != reportedLength) {
  143. if (msg->length < reportedLength) {
  144. Log_debug(context->logger, "DROP size field is larger than frame");
  145. return;
  146. }
  147. msg->length = reportedLength;
  148. }
  149. if (hdr.fc00_be != Endian_hostToBigEndian16(0xfc00)) {
  150. Log_debug(context->logger, "DROP bad magic");
  151. return;
  152. }
  153. struct ETHInterface_Sockaddr sockaddr = { .zero = 0 };
  154. Bits_memcpyConst(sockaddr.mac, addr.sll_addr, 6);
  155. sockaddr.generic.addrLen = ETHInterface_Sockaddr_SIZE;
  156. if (addr.sll_pkttype == PACKET_BROADCAST) {
  157. sockaddr.generic.flags |= Sockaddr_flags_BCAST;
  158. }
  159. Message_push(msg, &sockaddr, ETHInterface_Sockaddr_SIZE, NULL);
  160. Assert_true(!((uintptr_t)msg->bytes % 4) && "Alignment fault");
  161. Iface_send(&context->pub.generic.iface, msg);
  162. }
  163. static void handleEvent(void* vcontext)
  164. {
  165. struct ETHInterface_pvt* context = Identity_check((struct ETHInterface_pvt*) vcontext);
  166. struct Allocator* messageAlloc = Allocator_child(context->pub.generic.alloc);
  167. handleEvent2(context, messageAlloc);
  168. Allocator_free(messageAlloc);
  169. }
  170. List* ETHInterface_listDevices(struct Allocator* alloc, struct Except* eh)
  171. {
  172. List* out = List_new(alloc);
  173. #ifndef android
  174. struct ifaddrs* ifaddr = NULL;
  175. if (getifaddrs(&ifaddr) || ifaddr == NULL) {
  176. Except_throw(eh, "getifaddrs() -> errno:%d [%s]", errno, strerror(errno));
  177. }
  178. for (struct ifaddrs* ifa = ifaddr; ifa; ifa = ifa->ifa_next) {
  179. if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_PACKET) {
  180. List_addString(out, String_new(ifa->ifa_name, alloc), alloc);
  181. }
  182. }
  183. freeifaddrs(ifaddr);
  184. #endif
  185. return out;
  186. }
  187. static int closeSocket(struct Allocator_OnFreeJob* j)
  188. {
  189. struct ETHInterface_pvt* ctx = Identity_check((struct ETHInterface_pvt*) j->userData);
  190. close(ctx->socket);
  191. return 0;
  192. }
  193. struct ETHInterface* ETHInterface_new(struct EventBase* eventBase,
  194. const char* bindDevice,
  195. struct Allocator* alloc,
  196. struct Except* exHandler,
  197. struct Log* logger)
  198. {
  199. struct ETHInterface_pvt* ctx = Allocator_calloc(alloc, sizeof(struct ETHInterface_pvt), 1);
  200. Identity_set(ctx);
  201. ctx->pub.generic.iface.send = sendMessage;
  202. ctx->pub.generic.alloc = alloc;
  203. ctx->logger = logger;
  204. struct ifreq ifr = { .ifr_ifindex = 0 };
  205. ctx->socket = socket(AF_PACKET, SOCK_DGRAM, Ethernet_TYPE_CJDNS);
  206. if (ctx->socket == -1) {
  207. Except_throw(exHandler, "call to socket() failed. [%s]", strerror(errno));
  208. }
  209. Allocator_onFree(alloc, closeSocket, ctx);
  210. CString_strncpy(ifr.ifr_name, bindDevice, IFNAMSIZ - 1);
  211. ctx->ifName = String_new(bindDevice, alloc);
  212. if (ioctl(ctx->socket, SIOCGIFINDEX, &ifr) == -1) {
  213. Except_throw(exHandler, "failed to find interface index [%s]", strerror(errno));
  214. }
  215. ctx->ifindex = ifr.ifr_ifindex;
  216. if (ioctl(ctx->socket, SIOCGIFFLAGS, &ifr) < 0) {
  217. Except_throw(exHandler, "ioctl(SIOCGIFFLAGS) [%s]", strerror(errno));
  218. }
  219. if (!((ifr.ifr_flags & IFF_UP) && (ifr.ifr_flags & IFF_RUNNING))) {
  220. Log_info(logger, "Bringing up interface [%s]", ifr.ifr_name);
  221. ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
  222. if (ioctl(ctx->socket, SIOCSIFFLAGS, &ifr) < 0) {
  223. Except_throw(exHandler, "ioctl(SIOCSIFFLAGS) [%s]", strerror(errno));
  224. }
  225. }
  226. ctx->addrBase = (struct sockaddr_ll) {
  227. .sll_family = AF_PACKET,
  228. .sll_protocol = Ethernet_TYPE_CJDNS,
  229. .sll_ifindex = ctx->ifindex,
  230. .sll_hatype = ARPHRD_ETHER,
  231. .sll_pkttype = PACKET_OTHERHOST,
  232. .sll_halen = ETH_ALEN
  233. };
  234. if (bind(ctx->socket, (struct sockaddr*) &ctx->addrBase, sizeof(struct sockaddr_ll))) {
  235. Except_throw(exHandler, "call to bind() failed [%s]", strerror(errno));
  236. }
  237. Socket_makeNonBlocking(ctx->socket);
  238. Event_socketRead(handleEvent, ctx, ctx->socket, eventBase, alloc, exHandler);
  239. return &ctx->pub;
  240. }