2 * DHCP feature; applied as an input feature to select DHCP packets
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:
9 * http://www.apache.org/licenses/LICENSE-2.0
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.
18 #include <vnet/dhcp/client.h>
19 #include <vnet/udp/udp.h>
21 #define foreach_dhcp_client_detect \
26 #define _(sym,str) DHCP_CLIENT_DETECT_ERROR_##sym,
27 foreach_dhcp_client_detect
29 DHCP_CLIENT_DETECT_N_ERROR,
30 } dhcp_client_detect_error_t;
32 static char *dhcp_client_detect_error_strings[] = {
33 #define _(sym,string) string,
34 foreach_dhcp_client_detect
40 #define _(sym,str) DHCP_CLIENT_DETECT_NEXT_##sym,
41 foreach_dhcp_client_detect
43 DHCP_CLIENT_DETECT_N_NEXT,
44 } dhcp_client_detect_next_t;
47 * per-packet trace data
49 typedef struct dhcp_client_detect_trace_t_
51 /* per-pkt trace data */
53 } dhcp_client_detect_trace_t;
56 dhcp_client_detect_node_fn (vlib_main_t * vm,
57 vlib_node_runtime_t * node, vlib_frame_t * frame)
59 dhcp_client_detect_next_t next_index;
60 u16 dhcp_client_port_network_order;
61 u32 n_left_from, *from, *to_next;
64 dhcp_client_port_network_order =
65 clib_net_to_host_u16 (UDP_DST_PORT_dhcp_to_client);
68 n_left_from = frame->n_vectors;
69 from = vlib_frame_vector_args (frame);
71 while (n_left_from > 0)
75 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
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 receving 'normal' packets
82 while (n_left_from >= 8 && n_left_to_next >= 4)
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;
90 next0 = next1 = next2 = next3 = ~0;
91 bi0 = to_next[0] = from[0];
92 bi1 = to_next[1] = from[1];
93 bi2 = to_next[2] = from[2];
94 bi3 = to_next[3] = from[3];
96 /* Prefetch next iteration. */
98 vlib_buffer_t *p2, *p3, *p4, *p5;
100 p2 = vlib_get_buffer (vm, from[2]);
101 p3 = vlib_get_buffer (vm, from[3]);
102 p4 = vlib_get_buffer (vm, from[4]);
103 p5 = vlib_get_buffer (vm, from[5]);
105 vlib_prefetch_buffer_header (p2, STORE);
106 vlib_prefetch_buffer_header (p3, STORE);
107 vlib_prefetch_buffer_header (p4, STORE);
108 vlib_prefetch_buffer_header (p5, STORE);
110 CLIB_PREFETCH (p2->data, sizeof (ip0[0]) + sizeof (udp0[0]),
112 CLIB_PREFETCH (p3->data, sizeof (ip0[0]) + sizeof (udp0[0]),
114 CLIB_PREFETCH (p4->data, sizeof (ip0[0]) + sizeof (udp0[0]),
116 CLIB_PREFETCH (p5->data, sizeof (ip0[0]) + sizeof (udp0[0]),
125 b0 = vlib_get_buffer (vm, bi0);
126 b1 = vlib_get_buffer (vm, bi1);
127 b2 = vlib_get_buffer (vm, bi2);
128 b3 = vlib_get_buffer (vm, bi3);
129 ip0 = vlib_buffer_get_current (b0);
130 ip1 = vlib_buffer_get_current (b1);
131 ip2 = vlib_buffer_get_current (b2);
132 ip3 = vlib_buffer_get_current (b2);
134 vnet_feature_next (&next0, b0);
135 vnet_feature_next (&next1, b1);
136 vnet_feature_next (&next2, b2);
137 vnet_feature_next (&next3, b3);
139 if (ip0->protocol == IP_PROTOCOL_UDP)
141 udp0 = (udp_header_t *) (ip0 + 1);
143 if (dhcp_client_port_network_order == udp0->dst_port)
145 next0 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
149 if (ip1->protocol == IP_PROTOCOL_UDP)
151 udp1 = (udp_header_t *) (ip1 + 1);
153 if (dhcp_client_port_network_order == udp1->dst_port)
155 next1 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
159 if (ip2->protocol == IP_PROTOCOL_UDP)
161 udp2 = (udp_header_t *) (ip2 + 1);
163 if (dhcp_client_port_network_order == udp2->dst_port)
165 next2 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
169 if (ip3->protocol == IP_PROTOCOL_UDP)
171 udp3 = (udp_header_t *) (ip3 + 1);
173 if (dhcp_client_port_network_order == udp3->dst_port)
175 next3 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
180 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
182 dhcp_client_detect_trace_t *t =
183 vlib_add_trace (vm, node, b0, sizeof (*t));
184 t->extracted = (next0 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
186 if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
188 dhcp_client_detect_trace_t *t =
189 vlib_add_trace (vm, node, b1, sizeof (*t));
190 t->extracted = (next1 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
192 if (PREDICT_FALSE (b2->flags & VLIB_BUFFER_IS_TRACED))
194 dhcp_client_detect_trace_t *t =
195 vlib_add_trace (vm, node, b2, sizeof (*t));
196 t->extracted = (next2 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
198 if (PREDICT_FALSE (b3->flags & VLIB_BUFFER_IS_TRACED))
200 dhcp_client_detect_trace_t *t =
201 vlib_add_trace (vm, node, b3, sizeof (*t));
202 t->extracted = (next3 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
205 /* verify speculative enqueue, maybe switch current next frame */
206 vlib_validate_buffer_enqueue_x4 (vm, node, next_index,
207 to_next, n_left_to_next,
209 next0, next1, next2, next3);
212 while (n_left_from > 0 && n_left_to_next > 0)
227 b0 = vlib_get_buffer (vm, bi0);
228 ip0 = vlib_buffer_get_current (b0);
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.
236 vnet_feature_next (&next0, b0);
239 * all we are looking for here is DHCP/BOOTP packet-to-client
242 if (ip0->protocol == IP_PROTOCOL_UDP)
244 udp0 = (udp_header_t *) (ip0 + 1);
246 if (dhcp_client_port_network_order == udp0->dst_port)
248 next0 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
253 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
255 dhcp_client_detect_trace_t *t =
256 vlib_add_trace (vm, node, b0, sizeof (*t));
257 t->extracted = (next0 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
260 /* verify speculative enqueue, maybe switch current next frame */
261 vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
262 to_next, n_left_to_next,
266 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
269 vlib_node_increment_counter (vm, node->node_index,
270 DHCP_CLIENT_DETECT_ERROR_EXTRACT, extractions);
272 return frame->n_vectors;
275 /* packet trace format function */
277 format_dhcp_client_detect_trace (u8 * s, va_list * args)
279 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
280 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
281 dhcp_client_detect_trace_t *t =
282 va_arg (*args, dhcp_client_detect_trace_t *);
284 s = format (s, "dhcp-client-detect: %s", (t->extracted ? "yes" : "no"));
290 VLIB_REGISTER_NODE (dhcp_client_detect_node) = {
291 .function = dhcp_client_detect_node_fn,
292 .name = "ip4-dhcp-client-detect",
293 .vector_size = sizeof (u32),
294 .format_trace = format_dhcp_client_detect_trace,
295 .type = VLIB_NODE_TYPE_INTERNAL,
297 .n_errors = ARRAY_LEN(dhcp_client_detect_error_strings),
298 .error_strings = dhcp_client_detect_error_strings,
300 .n_next_nodes = DHCP_CLIENT_DETECT_N_NEXT,
303 * Jump straight to the UDP dispatch node thus avoiding
304 * the RPF checks in ip4-local that will fail
306 [DHCP_CLIENT_DETECT_NEXT_EXTRACT] = "ip4-udp-lookup",
310 VLIB_NODE_FUNCTION_MULTIARCH (dhcp_client_detect_node,
311 dhcp_client_detect_node_fn);
313 VNET_FEATURE_INIT (ip4_dvr_reinject_feat_node, static) =
315 .arc_name = "ip4-unicast",
316 .node_name = "ip4-dhcp-client-detect",
317 .runs_before = VNET_FEATURES ("ip4-not-enabled"),
323 * fd.io coding-style-patch-verification: ON
326 * eval: (c-set-style "gnu")