Line data Source code
1 : /*
2 : * DHCP feature; applied as an input feature to select DHCP packets
3 : *
4 : * Copyright (c) 2013 Cisco and/or its affiliates.
5 : * Licensed under the Apache License, Version 2.0 (the "License");
6 : * you may not use this file except in compliance with the License.
7 : * You may obtain a copy of the License at:
8 : *
9 : * http://www.apache.org/licenses/LICENSE-2.0
10 : *
11 : * Unless required by applicable law or agreed to in writing, software
12 : * distributed under the License is distributed on an "AS IS" BASIS,
13 : * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 : * See the License for the specific language governing permissions and
15 : * limitations under the License.
16 : */
17 :
18 : #include <dhcp/client.h>
19 : #include <vnet/udp/udp_local.h>
20 :
21 : #define foreach_dhcp_client_detect \
22 : _(EXTRACT, "Extract")
23 :
24 : typedef enum
25 : {
26 : #define _(sym,str) DHCP_CLIENT_DETECT_ERROR_##sym,
27 : foreach_dhcp_client_detect
28 : #undef _
29 : DHCP_CLIENT_DETECT_N_ERROR,
30 : } dhcp_client_detect_error_t;
31 :
32 : static char *dhcp_client_detect_error_strings[] = {
33 : #define _(sym,string) string,
34 : foreach_dhcp_client_detect
35 : #undef _
36 : };
37 :
38 : typedef enum
39 : {
40 : #define _(sym,str) DHCP_CLIENT_DETECT_NEXT_##sym,
41 : foreach_dhcp_client_detect
42 : #undef _
43 : DHCP_CLIENT_DETECT_N_NEXT,
44 : } dhcp_client_detect_next_t;
45 :
46 : /**
47 : * per-packet trace data
48 : */
49 : typedef struct dhcp_client_detect_trace_t_
50 : {
51 : /* per-pkt trace data */
52 : u8 extracted;
53 : } dhcp_client_detect_trace_t;
54 :
55 2309 : VLIB_NODE_FN (dhcp_client_detect_node) (vlib_main_t * vm,
56 : vlib_node_runtime_t * node,
57 : vlib_frame_t * frame)
58 : {
59 : dhcp_client_detect_next_t next_index;
60 : u16 dhcp_client_port_network_order;
61 : u32 n_left_from, *from, *to_next;
62 : u32 extractions;
63 :
64 : dhcp_client_port_network_order =
65 9 : clib_net_to_host_u16 (UDP_DST_PORT_dhcp_to_client);
66 9 : next_index = 0;
67 9 : extractions = 0;
68 9 : n_left_from = frame->n_vectors;
69 9 : from = vlib_frame_vector_args (frame);
70 :
71 18 : while (n_left_from > 0)
72 : {
73 : u32 n_left_to_next;
74 :
75 9 : vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
76 :
77 : /*
78 : * This loop is optimised not so we can really quickly process DHCp
79 : * offers... but so we can quickly sift them out when the interface
80 : * is also receiving 'normal' packets
81 : */
82 9 : while (n_left_from >= 8 && n_left_to_next >= 4)
83 : {
84 : udp_header_t *udp0, *udp1, *udp2, *udp3;
85 : ip4_header_t *ip0, *ip1, *ip2, *ip3;
86 : vlib_buffer_t *b0, *b1, *b2, *b3;
87 : u32 next0, next1, next2, next3;
88 : u32 bi0, bi1, bi2, bi3;
89 :
90 0 : next0 = next1 = next2 = next3 = ~0;
91 0 : bi0 = to_next[0] = from[0];
92 0 : bi1 = to_next[1] = from[1];
93 0 : bi2 = to_next[2] = from[2];
94 0 : bi3 = to_next[3] = from[3];
95 :
96 : /* Prefetch next iteration. */
97 : {
98 : vlib_buffer_t *p2, *p3, *p4, *p5;
99 :
100 0 : p2 = vlib_get_buffer (vm, from[2]);
101 0 : p3 = vlib_get_buffer (vm, from[3]);
102 0 : p4 = vlib_get_buffer (vm, from[4]);
103 0 : p5 = vlib_get_buffer (vm, from[5]);
104 :
105 0 : vlib_prefetch_buffer_header (p2, STORE);
106 0 : vlib_prefetch_buffer_header (p3, STORE);
107 0 : vlib_prefetch_buffer_header (p4, STORE);
108 0 : vlib_prefetch_buffer_header (p5, STORE);
109 :
110 0 : CLIB_PREFETCH (p2->data, sizeof (ip0[0]) + sizeof (udp0[0]),
111 : STORE);
112 0 : CLIB_PREFETCH (p3->data, sizeof (ip0[0]) + sizeof (udp0[0]),
113 : STORE);
114 0 : CLIB_PREFETCH (p4->data, sizeof (ip0[0]) + sizeof (udp0[0]),
115 : STORE);
116 0 : CLIB_PREFETCH (p5->data, sizeof (ip0[0]) + sizeof (udp0[0]),
117 : STORE);
118 : }
119 :
120 0 : from += 4;
121 0 : to_next += 4;
122 0 : n_left_from -= 4;
123 0 : n_left_to_next -= 4;
124 :
125 0 : b0 = vlib_get_buffer (vm, bi0);
126 0 : b1 = vlib_get_buffer (vm, bi1);
127 0 : b2 = vlib_get_buffer (vm, bi2);
128 0 : b3 = vlib_get_buffer (vm, bi3);
129 0 : ip0 = vlib_buffer_get_current (b0);
130 0 : ip1 = vlib_buffer_get_current (b1);
131 0 : ip2 = vlib_buffer_get_current (b2);
132 0 : ip3 = vlib_buffer_get_current (b2);
133 :
134 0 : vnet_feature_next (&next0, b0);
135 0 : vnet_feature_next (&next1, b1);
136 0 : vnet_feature_next (&next2, b2);
137 0 : vnet_feature_next (&next3, b3);
138 :
139 0 : if (ip0->protocol == IP_PROTOCOL_UDP)
140 : {
141 0 : udp0 = (udp_header_t *) (ip0 + 1);
142 :
143 0 : if (dhcp_client_port_network_order == udp0->dst_port)
144 : {
145 0 : next0 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
146 0 : extractions++;
147 : }
148 : }
149 0 : if (ip1->protocol == IP_PROTOCOL_UDP)
150 : {
151 0 : udp1 = (udp_header_t *) (ip1 + 1);
152 :
153 0 : if (dhcp_client_port_network_order == udp1->dst_port)
154 : {
155 0 : next1 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
156 0 : extractions++;
157 : }
158 : }
159 0 : if (ip2->protocol == IP_PROTOCOL_UDP)
160 : {
161 0 : udp2 = (udp_header_t *) (ip2 + 1);
162 :
163 0 : if (dhcp_client_port_network_order == udp2->dst_port)
164 : {
165 0 : next2 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
166 0 : extractions++;
167 : }
168 : }
169 0 : if (ip3->protocol == IP_PROTOCOL_UDP)
170 : {
171 0 : udp3 = (udp_header_t *) (ip3 + 1);
172 :
173 0 : if (dhcp_client_port_network_order == udp3->dst_port)
174 : {
175 0 : next3 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
176 0 : extractions++;
177 : }
178 : }
179 :
180 0 : if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
181 : {
182 : dhcp_client_detect_trace_t *t =
183 0 : vlib_add_trace (vm, node, b0, sizeof (*t));
184 0 : t->extracted = (next0 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
185 : }
186 0 : if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
187 : {
188 : dhcp_client_detect_trace_t *t =
189 0 : vlib_add_trace (vm, node, b1, sizeof (*t));
190 0 : t->extracted = (next1 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
191 : }
192 0 : if (PREDICT_FALSE (b2->flags & VLIB_BUFFER_IS_TRACED))
193 : {
194 : dhcp_client_detect_trace_t *t =
195 0 : vlib_add_trace (vm, node, b2, sizeof (*t));
196 0 : t->extracted = (next2 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
197 : }
198 0 : if (PREDICT_FALSE (b3->flags & VLIB_BUFFER_IS_TRACED))
199 : {
200 : dhcp_client_detect_trace_t *t =
201 0 : vlib_add_trace (vm, node, b3, sizeof (*t));
202 0 : t->extracted = (next3 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
203 : }
204 :
205 : /* verify speculative enqueue, maybe switch current next frame */
206 0 : vlib_validate_buffer_enqueue_x4 (vm, node, next_index,
207 : to_next, n_left_to_next,
208 : bi0, bi1, bi2, bi3,
209 : next0, next1, next2, next3);
210 : }
211 :
212 18 : while (n_left_from > 0 && n_left_to_next > 0)
213 : {
214 : udp_header_t *udp0;
215 : vlib_buffer_t *b0;
216 : ip4_header_t *ip0;
217 9 : u32 next0 = ~0;
218 : u32 bi0;
219 :
220 9 : bi0 = from[0];
221 9 : to_next[0] = bi0;
222 9 : from += 1;
223 9 : to_next += 1;
224 9 : n_left_from -= 1;
225 9 : n_left_to_next -= 1;
226 :
227 9 : b0 = vlib_get_buffer (vm, bi0);
228 9 : ip0 = vlib_buffer_get_current (b0);
229 :
230 : /*
231 : * when this feature is applied on an interface that is already
232 : * accepting packets (because e.g. the interface has other addresses
233 : * assigned) we are looking for the preverbial needle in the haystack
234 : * so assume the packet is not the one we are looking for.
235 : */
236 9 : vnet_feature_next (&next0, b0);
237 :
238 : /*
239 : * all we are looking for here is DHCP/BOOTP packet-to-client
240 : * UDO port.
241 : */
242 9 : if (ip0->protocol == IP_PROTOCOL_UDP)
243 : {
244 9 : udp0 = (udp_header_t *) (ip0 + 1);
245 :
246 9 : if (dhcp_client_port_network_order == udp0->dst_port)
247 : {
248 9 : next0 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
249 9 : extractions++;
250 : }
251 : }
252 :
253 9 : if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
254 : {
255 : dhcp_client_detect_trace_t *t =
256 9 : vlib_add_trace (vm, node, b0, sizeof (*t));
257 9 : t->extracted = (next0 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
258 : }
259 :
260 : /* verify speculative enqueue, maybe switch current next frame */
261 9 : vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
262 : to_next, n_left_to_next,
263 : bi0, next0);
264 : }
265 :
266 9 : vlib_put_next_frame (vm, node, next_index, n_left_to_next);
267 : }
268 :
269 9 : vlib_node_increment_counter (vm, node->node_index,
270 : DHCP_CLIENT_DETECT_ERROR_EXTRACT, extractions);
271 :
272 9 : return frame->n_vectors;
273 : }
274 :
275 : /* packet trace format function */
276 : static u8 *
277 1 : format_dhcp_client_detect_trace (u8 * s, va_list * args)
278 : {
279 1 : CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
280 1 : CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
281 1 : dhcp_client_detect_trace_t *t =
282 : va_arg (*args, dhcp_client_detect_trace_t *);
283 :
284 1 : s = format (s, "dhcp-client-detect: %s", (t->extracted ? "yes" : "no"));
285 :
286 1 : return s;
287 : }
288 :
289 : /* *INDENT-OFF* */
290 153836 : VLIB_REGISTER_NODE (dhcp_client_detect_node) = {
291 : .name = "ip4-dhcp-client-detect",
292 : .vector_size = sizeof (u32),
293 : .format_trace = format_dhcp_client_detect_trace,
294 : .type = VLIB_NODE_TYPE_INTERNAL,
295 :
296 : .n_errors = ARRAY_LEN(dhcp_client_detect_error_strings),
297 : .error_strings = dhcp_client_detect_error_strings,
298 :
299 : .n_next_nodes = DHCP_CLIENT_DETECT_N_NEXT,
300 : .next_nodes = {
301 : /*
302 : * Jump straight to the UDP dispatch node thus avoiding
303 : * the RPF checks in ip4-local that will fail
304 : */
305 : [DHCP_CLIENT_DETECT_NEXT_EXTRACT] = "ip4-udp-lookup",
306 : },
307 : };
308 :
309 61659 : VNET_FEATURE_INIT (ip4_dvr_reinject_feat_node, static) =
310 : {
311 : .arc_name = "ip4-unicast",
312 : .node_name = "ip4-dhcp-client-detect",
313 : .runs_before = VNET_FEATURES ("ip4-not-enabled"),
314 : };
315 :
316 : /* *INDENT-ON* */
317 :
318 : /*
319 : * fd.io coding-style-patch-verification: ON
320 : *
321 : * Local Variables:
322 : * eval: (c-set-style "gnu")
323 : * End:
324 : */
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