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1 office 1 /**
2 * @file BDHCPClient.c
3 * @author Ambroz Bizjak <ambrop7@gmail.com>
4 *
5 * @section LICENSE
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the author nor the
15 * names of its contributors may be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
20 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
22 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
23 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
24 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
25 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
27 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29  
30 #include <stdio.h>
31 #include <string.h>
32 #include <unistd.h>
33 #include <sys/socket.h>
34 #include <net/if.h>
35 #include <net/if_arp.h>
36 #include <sys/ioctl.h>
37 #include <linux/filter.h>
38  
39 #include <misc/debug.h>
40 #include <misc/byteorder.h>
41 #include <misc/ethernet_proto.h>
42 #include <misc/ipv4_proto.h>
43 #include <misc/udp_proto.h>
44 #include <misc/dhcp_proto.h>
45 #include <misc/get_iface_info.h>
46 #include <base/BLog.h>
47  
48 #include <dhcpclient/BDHCPClient.h>
49  
50 #include <generated/blog_channel_BDHCPClient.h>
51  
52 #define DHCP_SERVER_PORT 67
53 #define DHCP_CLIENT_PORT 68
54  
55 #define IPUDP_OVERHEAD (sizeof(struct ipv4_header) + sizeof(struct udp_header))
56  
57 static const struct sock_filter dhcp_sock_filter[] = {
58 BPF_STMT(BPF_LD + BPF_B + BPF_ABS, 9), // A <- IP protocol
59 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPV4_PROTOCOL_UDP, 0, 3), // IP protocol = UDP ?
60 BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 22), // A <- UDP destination port
61 BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_CLIENT_PORT, 0, 1), // UDP destination port = DHCP client ?
62 BPF_STMT(BPF_RET + BPF_K, 65535), // return all
63 BPF_STMT(BPF_RET + BPF_K, 0) // ignore
64 };
65  
66 static void dgram_handler (BDHCPClient *o, int event)
67 {
68 DebugObject_Access(&o->d_obj);
69  
70 BLog(BLOG_ERROR, "packet socket error");
71  
72 // report error
73 DEBUGERROR(&o->d_err, o->handler(o->user, BDHCPCLIENT_EVENT_ERROR));
74 return;
75 }
76  
77 static void dhcp_handler (BDHCPClient *o, int event)
78 {
79 DebugObject_Access(&o->d_obj);
80  
81 switch (event) {
82 case BDHCPCLIENTCORE_EVENT_UP:
83 ASSERT(!o->up)
84 o->up = 1;
85 o->handler(o->user, BDHCPCLIENT_EVENT_UP);
86 return;
87  
88 case BDHCPCLIENTCORE_EVENT_DOWN:
89 ASSERT(o->up)
90 o->up = 0;
91 o->handler(o->user, BDHCPCLIENT_EVENT_DOWN);
92 return;
93  
94 default:
95 ASSERT(0);
96 }
97 }
98  
99 static void dhcp_func_getsendermac (BDHCPClient *o, uint8_t *out_mac)
100 {
101 DebugObject_Access(&o->d_obj);
102  
103 BAddr remote_addr;
104 BIPAddr local_addr;
105 if (!BDatagram_GetLastReceiveAddrs(&o->dgram, &remote_addr, &local_addr)) {
106 BLog(BLOG_ERROR, "BDatagram_GetLastReceiveAddrs failed");
107 goto fail;
108 }
109  
110 if (remote_addr.type != BADDR_TYPE_PACKET) {
111 BLog(BLOG_ERROR, "address type invalid");
112 goto fail;
113 }
114  
115 if (remote_addr.packet.header_type != BADDR_PACKET_HEADER_TYPE_ETHERNET) {
116 BLog(BLOG_ERROR, "address header type invalid");
117 goto fail;
118 }
119  
120 memcpy(out_mac, remote_addr.packet.phys_addr, 6);
121 return;
122  
123 fail:
124 memset(out_mac, 0, 6);
125 }
126  
127 int BDHCPClient_Init (BDHCPClient *o, const char *ifname, struct BDHCPClient_opts opts, BReactor *reactor, BRandom2 *random2, BDHCPClient_handler handler, void *user)
128 {
129 // init arguments
130 o->reactor = reactor;
131 o->handler = handler;
132 o->user = user;
133  
134 // get interface information
135 uint8_t if_mac[6];
136 int if_mtu;
137 int if_index;
138 if (!badvpn_get_iface_info(ifname, if_mac, &if_mtu, &if_index)) {
139 BLog(BLOG_ERROR, "failed to get interface information");
140 goto fail0;
141 }
142  
143 BLog(BLOG_INFO, "if_mac=%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8" if_mtu=%d if_index=%d",
144 if_mac[0], if_mac[1], if_mac[2], if_mac[3], if_mac[4], if_mac[5], if_mtu, if_index);
145  
146 if (if_mtu < IPUDP_OVERHEAD) {
147 BLog(BLOG_ERROR, "MTU is too small for UDP/IP !?!");
148 goto fail0;
149 }
150  
151 int dhcp_mtu = if_mtu - IPUDP_OVERHEAD;
152  
153 // init dgram
154 if (!BDatagram_Init(&o->dgram, BADDR_TYPE_PACKET, o->reactor, o, (BDatagram_handler)dgram_handler)) {
155 BLog(BLOG_ERROR, "BDatagram_Init failed");
156 goto fail0;
157 }
158  
159 // set socket filter
160 {
161 struct sock_filter filter[sizeof(dhcp_sock_filter) / sizeof(dhcp_sock_filter[0])];
162 memcpy(filter, dhcp_sock_filter, sizeof(filter));
163 struct sock_fprog fprog = {
164 .len = sizeof(filter) / sizeof(filter[0]),
165 .filter = filter
166 };
167 if (setsockopt(BDatagram_GetFd(&o->dgram), SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)) < 0) {
168 BLog(BLOG_NOTICE, "not using socket filter");
169 }
170 }
171  
172 // bind dgram
173 BAddr bind_addr;
174 BAddr_InitPacket(&bind_addr, hton16(ETHERTYPE_IPV4), if_index, BADDR_PACKET_HEADER_TYPE_ETHERNET, BADDR_PACKET_PACKET_TYPE_HOST, if_mac);
175 if (!BDatagram_Bind(&o->dgram, bind_addr)) {
176 BLog(BLOG_ERROR, "BDatagram_Bind failed");
177 goto fail1;
178 }
179  
180 // set dgram send addresses
181 BAddr dest_addr;
182 uint8_t broadcast_mac[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
183 BAddr_InitPacket(&dest_addr, hton16(ETHERTYPE_IPV4), if_index, BADDR_PACKET_HEADER_TYPE_ETHERNET, BADDR_PACKET_PACKET_TYPE_BROADCAST, broadcast_mac);
184 BIPAddr local_addr;
185 BIPAddr_InitInvalid(&local_addr);
186 BDatagram_SetSendAddrs(&o->dgram, dest_addr, local_addr);
187  
188 // init dgram interfaces
189 BDatagram_SendAsync_Init(&o->dgram, if_mtu);
190 BDatagram_RecvAsync_Init(&o->dgram, if_mtu);
191  
192 // init sending
193  
194 // init copier
195 PacketCopier_Init(&o->send_copier, dhcp_mtu, BReactor_PendingGroup(o->reactor));
196  
197 // init encoder
198 DHCPIpUdpEncoder_Init(&o->send_encoder, PacketCopier_GetOutput(&o->send_copier), BReactor_PendingGroup(o->reactor));
199  
200 // init buffer
201 if (!SinglePacketBuffer_Init(&o->send_buffer, DHCPIpUdpEncoder_GetOutput(&o->send_encoder), BDatagram_SendAsync_GetIf(&o->dgram), BReactor_PendingGroup(o->reactor))) {
202 BLog(BLOG_ERROR, "SinglePacketBuffer_Init failed");
203 goto fail2;
204 }
205  
206 // init receiving
207  
208 // init copier
209 PacketCopier_Init(&o->recv_copier, dhcp_mtu, BReactor_PendingGroup(o->reactor));
210  
211 // init decoder
212 DHCPIpUdpDecoder_Init(&o->recv_decoder, PacketCopier_GetInput(&o->recv_copier), BReactor_PendingGroup(o->reactor));
213  
214 // init buffer
215 if (!SinglePacketBuffer_Init(&o->recv_buffer, BDatagram_RecvAsync_GetIf(&o->dgram), DHCPIpUdpDecoder_GetInput(&o->recv_decoder), BReactor_PendingGroup(o->reactor))) {
216 BLog(BLOG_ERROR, "SinglePacketBuffer_Init failed");
217 goto fail3;
218 }
219  
220 // init options
221 struct BDHCPClientCore_opts core_opts;
222 core_opts.hostname = opts.hostname;
223 core_opts.vendorclassid = opts.vendorclassid;
224 core_opts.clientid = opts.clientid;
225 core_opts.clientid_len = opts.clientid_len;
226  
227 // auto-generate clientid from MAC if requested
228 uint8_t mac_cid[7];
229 if (opts.auto_clientid) {
230 mac_cid[0] = DHCP_HARDWARE_ADDRESS_TYPE_ETHERNET;
231 memcpy(mac_cid + 1, if_mac, 6);
232 core_opts.clientid = mac_cid;
233 core_opts.clientid_len = sizeof(mac_cid);
234 }
235  
236 // init dhcp
237 if (!BDHCPClientCore_Init(&o->dhcp, PacketCopier_GetInput(&o->send_copier), PacketCopier_GetOutput(&o->recv_copier), if_mac, core_opts, o->reactor, random2, o,
238 (BDHCPClientCore_func_getsendermac)dhcp_func_getsendermac,
239 (BDHCPClientCore_handler)dhcp_handler
240 )) {
241 BLog(BLOG_ERROR, "BDHCPClientCore_Init failed");
242 goto fail4;
243 }
244  
245 // set not up
246 o->up = 0;
247  
248 DebugError_Init(&o->d_err, BReactor_PendingGroup(o->reactor));
249 DebugObject_Init(&o->d_obj);
250 return 1;
251  
252 fail4:
253 SinglePacketBuffer_Free(&o->recv_buffer);
254 fail3:
255 DHCPIpUdpDecoder_Free(&o->recv_decoder);
256 PacketCopier_Free(&o->recv_copier);
257 SinglePacketBuffer_Free(&o->send_buffer);
258 fail2:
259 DHCPIpUdpEncoder_Free(&o->send_encoder);
260 PacketCopier_Free(&o->send_copier);
261 BDatagram_RecvAsync_Free(&o->dgram);
262 BDatagram_SendAsync_Free(&o->dgram);
263 fail1:
264 BDatagram_Free(&o->dgram);
265 fail0:
266 return 0;
267 }
268  
269 void BDHCPClient_Free (BDHCPClient *o)
270 {
271 DebugObject_Free(&o->d_obj);
272 DebugError_Free(&o->d_err);
273  
274 // free dhcp
275 BDHCPClientCore_Free(&o->dhcp);
276  
277 // free receiving
278 SinglePacketBuffer_Free(&o->recv_buffer);
279 DHCPIpUdpDecoder_Free(&o->recv_decoder);
280 PacketCopier_Free(&o->recv_copier);
281  
282 // free sending
283 SinglePacketBuffer_Free(&o->send_buffer);
284 DHCPIpUdpEncoder_Free(&o->send_encoder);
285 PacketCopier_Free(&o->send_copier);
286  
287 // free dgram interfaces
288 BDatagram_RecvAsync_Free(&o->dgram);
289 BDatagram_SendAsync_Free(&o->dgram);
290  
291 // free dgram
292 BDatagram_Free(&o->dgram);
293 }
294  
295 int BDHCPClient_IsUp (BDHCPClient *o)
296 {
297 DebugObject_Access(&o->d_obj);
298  
299 return o->up;
300 }
301  
302 void BDHCPClient_GetClientIP (BDHCPClient *o, uint32_t *out_ip)
303 {
304 DebugObject_Access(&o->d_obj);
305 ASSERT(o->up)
306  
307 BDHCPClientCore_GetClientIP(&o->dhcp, out_ip);
308 }
309  
310 void BDHCPClient_GetClientMask (BDHCPClient *o, uint32_t *out_mask)
311 {
312 DebugObject_Access(&o->d_obj);
313 ASSERT(o->up)
314  
315 BDHCPClientCore_GetClientMask(&o->dhcp, out_mask);
316 }
317  
318 int BDHCPClient_GetRouter (BDHCPClient *o, uint32_t *out_router)
319 {
320 DebugObject_Access(&o->d_obj);
321 ASSERT(o->up)
322  
323 return BDHCPClientCore_GetRouter(&o->dhcp, out_router);
324 }
325  
326 int BDHCPClient_GetDNS (BDHCPClient *o, uint32_t *out_dns_servers, size_t max_dns_servers)
327 {
328 DebugObject_Access(&o->d_obj);
329 ASSERT(o->up)
330  
331 return BDHCPClientCore_GetDNS(&o->dhcp, out_dns_servers, max_dns_servers);
332 }
333  
334 void BDHCPClient_GetServerMAC (BDHCPClient *o, uint8_t *out_mac)
335 {
336 DebugObject_Access(&o->d_obj);
337 ASSERT(o->up)
338  
339 BDHCPClientCore_GetServerMAC(&o->dhcp, out_mac);
340 }