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 "exception/Except.h"
  16. #include "interface/Interface.h"
  17. #include "interface/ETHInterface.h"
  18. #include "memory/Allocator.h"
  19. #include "interface/InterfaceController.h"
  20. #include "wire/Headers.h"
  21. #include "wire/Message.h"
  22. #include "wire/Error.h"
  23. #include "wire/Ethernet.h"
  24. #include "util/Assert.h"
  25. #include "util/platform/Socket.h"
  26. #include "util/events/Event.h"
  27. #include "util/Identity.h"
  28. #include "util/AddrTools.h"
  29. #include "util/version/Version.h"
  30. #include "util/events/Timeout.h"
  31. #include <string.h>
  32. #include <sys/socket.h>
  33. #include <linux/if_packet.h>
  34. #include <linux/if_ether.h>
  35. #include <linux/if_arp.h>
  36. #include <sys/types.h>
  37. #include <sys/ioctl.h>
  38. #include <unistd.h>
  39. #include <errno.h>
  40. #include <ifaddrs.h>
  41. #define MAX_PACKET_SIZE 1496
  42. #define MIN_PACKET_SIZE 46
  43. #define PADDING 512
  44. // 2 last 0x00 of .sll_addr are removed from original size (20)
  45. #define SOCKADDR_LL_LEN 18
  46. struct ETHInterface
  47. {
  48. struct Interface generic;
  49. Socket socket;
  50. /** The unix interface index which is used to identify the eth device. */
  51. int ifindex;
  52. struct Log* logger;
  53. struct sockaddr_ll addrBase;
  54. String* ifName;
  55. Identity
  56. };
  57. static uint8_t sendMessageInternal(struct Message* message,
  58. struct sockaddr_ll* addr,
  59. struct ETHInterface* context)
  60. {
  61. /* Cut down on the noise
  62. uint8_t buff[sizeof(*addr) * 2 + 1] = {0};
  63. Hex_encode(buff, sizeof(buff), (uint8_t*)addr, sizeof(*addr));
  64. Log_debug(context->logger, "Sending ethernet frame to [%s]", buff);
  65. */
  66. if (sendto(context->socket,
  67. message->bytes,
  68. message->length,
  69. 0,
  70. (struct sockaddr*) addr,
  71. sizeof(struct sockaddr_ll)) < 0)
  72. {
  73. switch (errno) {
  74. case EMSGSIZE:
  75. return Error_OVERSIZE_MESSAGE;
  76. case ENOBUFS:
  77. case EAGAIN:
  78. return Error_LINK_LIMIT_EXCEEDED;
  79. default:;
  80. Log_info(context->logger, "[%s] Got error sending to socket [%s]",
  81. context->ifName->bytes, strerror(errno));
  82. }
  83. }
  84. return 0;
  85. }
  86. static uint8_t sendMessage(struct Message* msg, struct Interface* ethIf)
  87. {
  88. struct ETHInterface* ctx = Identity_check((struct ETHInterface*) ethIf);
  89. struct Sockaddr* sa = (struct Sockaddr*) msg->bytes;
  90. Assert_true(msg->length >= Sockaddr_OVERHEAD);
  91. Assert_true(sa->addrLen <= ETHInterface_Sockaddr_SIZE);
  92. struct ETHInterface_Sockaddr sockaddr = { .generic = { .addrLen = 0 } };
  93. Message_pop(msg, &sockaddr, sa->addrLen, NULL);
  94. struct sockaddr_ll addr;
  95. Bits_memcpyConst(&addr, &ctx->addrBase, sizeof(struct sockaddr_ll));
  96. if (sockaddr.generic.flags & Sockaddr_flags_BCAST) {
  97. Bits_memset(addr.sll_addr, 0xff, 6);
  98. } else {
  99. Bits_memcpyConst(addr.sll_addr, sockaddr.mac, 6);
  100. }
  101. struct ETHInterface_Header hdr = {
  102. .version = ETHInterface_CURRENT_VERSION,
  103. .zero = 0,
  104. .length_be = Endian_hostToBigEndian16(msg->length + ETHInterface_Header_SIZE),
  105. .fc00_be = Endian_hostToBigEndian16(0xfc00)
  106. };
  107. Message_push(msg, &hdr, ETHInterface_Header_SIZE, NULL);
  108. return sendMessageInternal(msg, &addr, ctx);
  109. }
  110. static void handleEvent2(struct ETHInterface* context, struct Allocator* messageAlloc)
  111. {
  112. struct Message* msg = Message_new(MAX_PACKET_SIZE, PADDING, messageAlloc);
  113. struct sockaddr_ll addr;
  114. uint32_t addrLen = sizeof(struct sockaddr_ll);
  115. // Knock it out of alignment by 2 bytes so that it will be
  116. // aligned when the idAndPadding is shifted off.
  117. Message_shift(msg, 2, NULL);
  118. int rc = recvfrom(context->socket,
  119. msg->bytes,
  120. msg->length,
  121. 0,
  122. (struct sockaddr*) &addr,
  123. &addrLen);
  124. if (rc < ETHInterface_Header_SIZE) {
  125. Log_debug(context->logger, "Failed to receive eth frame");
  126. return;
  127. }
  128. Assert_true(msg->length >= rc);
  129. msg->length = rc;
  130. //Assert_true(addrLen == SOCKADDR_LL_LEN);
  131. struct ETHInterface_Header hdr;
  132. Message_pop(msg, &hdr, ETHInterface_Header_SIZE, NULL);
  133. // here we could put a switch statement to handle different versions differently.
  134. if (hdr.version != ETHInterface_CURRENT_VERSION) {
  135. Log_debug(context->logger, "DROP unknown version");
  136. return;
  137. }
  138. uint16_t reportedLength = Endian_bigEndianToHost16(hdr.length_be);
  139. reportedLength -= ETHInterface_Header_SIZE;
  140. if (msg->length != reportedLength) {
  141. if (msg->length < reportedLength) {
  142. Log_debug(context->logger, "DROP size field is larger than frame");
  143. return;
  144. }
  145. msg->length = reportedLength;
  146. }
  147. if (hdr.fc00_be != Endian_hostToBigEndian16(0xfc00)) {
  148. Log_debug(context->logger, "DROP bad magic");
  149. return;
  150. }
  151. struct ETHInterface_Sockaddr sockaddr = { .zero = 0 };
  152. Bits_memcpyConst(sockaddr.mac, addr.sll_addr, 6);
  153. sockaddr.generic.addrLen = ETHInterface_Sockaddr_SIZE;
  154. if (addr.sll_pkttype == PACKET_BROADCAST) {
  155. sockaddr.generic.flags |= Sockaddr_flags_BCAST;
  156. }
  157. Message_push(msg, &sockaddr, ETHInterface_Sockaddr_SIZE, NULL);
  158. Assert_true(!((uintptr_t)msg->bytes % 4) && "Alignment fault");
  159. Interface_receiveMessage(&context->generic, msg);
  160. }
  161. static void handleEvent(void* vcontext)
  162. {
  163. struct ETHInterface* context = Identity_check((struct ETHInterface*) vcontext);
  164. struct Allocator* messageAlloc = Allocator_child(context->generic.allocator);
  165. handleEvent2(context, messageAlloc);
  166. Allocator_free(messageAlloc);
  167. }
  168. List* ETHInterface_listDevices(struct Allocator* alloc, struct Except* eh)
  169. {
  170. struct ifaddrs* ifaddr = NULL;
  171. if (getifaddrs(&ifaddr) || ifaddr == NULL) {
  172. Except_throw(eh, "getifaddrs() -> errno:%d [%s]", errno, strerror(errno));
  173. }
  174. List* out = List_new(alloc);
  175. for (struct ifaddrs* ifa = ifaddr; ifa; ifa = ifa->ifa_next) {
  176. if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_PACKET) {
  177. List_addString(out, String_new(ifa->ifa_name, alloc), alloc);
  178. }
  179. }
  180. freeifaddrs(ifaddr);
  181. return out;
  182. }
  183. static int closeSocket(struct Allocator_OnFreeJob* j)
  184. {
  185. struct ETHInterface* ctx = Identity_check((struct ETHInterface*) j->userData);
  186. close(ctx->socket);
  187. return 0;
  188. }
  189. struct Interface* ETHInterface_new(struct EventBase* eventBase,
  190. const char* bindDevice,
  191. struct Allocator* alloc,
  192. struct Except* exHandler,
  193. struct Log* logger)
  194. {
  195. struct ETHInterface* ctx =
  196. Allocator_clone(alloc, (&(struct ETHInterface) {
  197. .generic = {
  198. .sendMessage = sendMessage,
  199. .allocator = alloc
  200. },
  201. .logger = logger
  202. }));
  203. Identity_set(ctx);
  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->generic;
  240. }