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authorDave Barach <dave@barachs.net>2017-10-10 17:53:14 -0400
committerFlorin Coras <florin.coras@gmail.com>2017-10-13 20:20:09 +0000
commit6545716c073c88ad86458620c6dbc59ba1cd00bb (patch)
tree2bd8b7d9cd0e221669081aba27786e1ce5eee964 /src/vnet/dns/reply_node.c
parent7e550693dffd368b9dd8e0397674cfc4d10f9579 (diff)
VPP-1027: DNS name resolver
This patch is a plausible first-cut, suitable for initial testing by vcl (host stack client library). Main features; - recursive name resolution - multiple ip4/ip6 name servers - cache size limit enforcement - currently limited to 65K - ttl / aging - static mapping support - show / clear / debug CLI commands Binary APIs provided for the following: - add/delete name servers - enable/disable the name cache - resolve a name To Do list: - Respond to ip4/ip6 client DNS requests (vs. binary API requests) - Perf / scale tuning - map pending transaction ids to pool indices, so the cache can (greatly) exceed 65K entries - Security improvements - Use unpredictable dns transaction IDs, related to previous item - Make sure that response-packet src ip addresses match the server - Add binary APIs - deliver raw response data to clients - control recursive name resolution - Documentation Change-Id: I48c373d5c05d7108ccd814d4055caf8c75ca10b7 Signed-off-by: Dave Barach <dave@barachs.net>
Diffstat (limited to 'src/vnet/dns/reply_node.c')
-rw-r--r--src/vnet/dns/reply_node.c214
1 files changed, 214 insertions, 0 deletions
diff --git a/src/vnet/dns/reply_node.c b/src/vnet/dns/reply_node.c
new file mode 100644
index 00000000000..e045ba8cda4
--- /dev/null
+++ b/src/vnet/dns/reply_node.c
@@ -0,0 +1,214 @@
+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vnet/dns/dns.h>
+
+#include <vlib/vlib.h>
+#include <vnet/vnet.h>
+
+vlib_node_registration_t dns46_reply_node;
+
+typedef struct
+{
+ u32 pool_index;
+ u32 disposition;
+} dns46_reply_trace_t;
+
+/* packet trace format function */
+static u8 *
+format_dns46_reply_trace (u8 * s, va_list * args)
+{
+ CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+ CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+ dns46_reply_trace_t *t = va_arg (*args, dns46_reply_trace_t *);
+
+ s = format (s, "DNS46_REPLY: pool index %d, disposition %d",
+ t->pool_index, t->disposition);
+ return s;
+}
+
+vlib_node_registration_t dns46_reply_node;
+
+static char *dns46_reply_error_strings[] = {
+#define _(sym,string) string,
+ foreach_dns46_reply_error
+#undef _
+};
+
+typedef enum
+{
+ DNS46_REPLY_NEXT_DROP,
+ DNS46_REPLY_N_NEXT,
+} dns46_reply_next_t;
+
+static uword
+dns46_reply_node_fn (vlib_main_t * vm,
+ vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+ u32 n_left_from, *from, *to_next;
+ dns46_reply_next_t next_index;
+
+ from = vlib_frame_vector_args (frame);
+ n_left_from = frame->n_vectors;
+ next_index = node->cached_next_index;
+
+ while (n_left_from > 0)
+ {
+ u32 n_left_to_next;
+
+ vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+#if 0
+ while (n_left_from >= 4 && n_left_to_next >= 2)
+ {
+ u32 next0 = DNS46_REPLY_NEXT_INTERFACE_OUTPUT;
+ u32 next1 = DNS46_REPLY_NEXT_INTERFACE_OUTPUT;
+ u32 sw_if_index0, sw_if_index1;
+ u8 tmp0[6], tmp1[6];
+ ethernet_header_t *en0, *en1;
+ u32 bi0, bi1;
+ vlib_buffer_t *b0, *b1;
+
+ /* Prefetch next iteration. */
+ {
+ vlib_buffer_t *p2, *p3;
+
+ p2 = vlib_get_buffer (vm, from[2]);
+ p3 = vlib_get_buffer (vm, from[3]);
+
+ vlib_prefetch_buffer_header (p2, LOAD);
+ vlib_prefetch_buffer_header (p3, LOAD);
+
+ CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
+ CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
+ }
+
+ /* speculatively enqueue b0 and b1 to the current next frame */
+ to_next[0] = bi0 = from[0];
+ to_next[1] = bi1 = from[1];
+ from += 2;
+ to_next += 2;
+ n_left_from -= 2;
+ n_left_to_next -= 2;
+
+ b0 = vlib_get_buffer (vm, bi0);
+ b1 = vlib_get_buffer (vm, bi1);
+
+ /* $$$$$ End of processing 2 x packets $$$$$ */
+
+ if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
+ {
+ if (b0->flags & VLIB_BUFFER_IS_TRACED)
+ {
+ dns46_reply_trace_t *t =
+ vlib_add_trace (vm, node, b0, sizeof (*t));
+ t->sw_if_index = sw_if_index0;
+ t->next_index = next0;
+ }
+ if (b1->flags & VLIB_BUFFER_IS_TRACED)
+ {
+ dns46_reply_trace_t *t =
+ vlib_add_trace (vm, node, b1, sizeof (*t));
+ t->sw_if_index = sw_if_index1;
+ t->next_index = next1;
+ }
+ }
+
+ /* verify speculative enqueues, maybe switch current next frame */
+ vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
+ to_next, n_left_to_next,
+ bi0, bi1, next0, next1);
+ }
+#endif
+
+ while (n_left_from > 0 && n_left_to_next > 0)
+ {
+ u32 bi0;
+ vlib_buffer_t *b0;
+ u32 next0 = DNS46_REPLY_NEXT_DROP;
+ dns_header_t *d0;
+ u32 pool_index0;
+ u32 error0;
+ u8 *resp0 = 0;
+
+ /* speculatively enqueue b0 to the current next frame */
+ bi0 = from[0];
+ to_next[0] = bi0;
+ from += 1;
+ to_next += 1;
+ n_left_from -= 1;
+
+ n_left_to_next -= 1;
+
+ b0 = vlib_get_buffer (vm, bi0);
+ d0 = vlib_buffer_get_current (b0);
+
+ pool_index0 = clib_host_to_net_u16 (d0->id);
+
+ /* Save the reply */
+ vec_validate (resp0, vlib_buffer_length_in_chain (vm, b0) - 1);
+ clib_memcpy (resp0, d0, vlib_buffer_length_in_chain (vm, b0));
+
+ /*
+ * Deal with everything in process ctx on the main thread
+ */
+ vlib_process_signal_event_mt (vm, dns_resolver_node.index,
+ DNS_RESOLVER_EVENT_RESOLVED,
+ (uword) resp0);
+ error0 = DNS46_REPLY_ERROR_PROCESSED;
+
+ b0->error = node->errors[error0];
+
+ if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+ && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+ {
+ dns46_reply_trace_t *t =
+ vlib_add_trace (vm, node, b0, sizeof (*t));
+ t->disposition = error0;
+ t->pool_index = pool_index0;
+ }
+
+ /* verify speculative enqueue, maybe switch current next frame */
+ vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+ to_next, n_left_to_next,
+ bi0, next0);
+ }
+
+ vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+ }
+
+ return frame->n_vectors;
+}
+
+VLIB_REGISTER_NODE (dns46_reply_node) =
+{
+ .function = dns46_reply_node_fn,.name = "dns46_reply",.vector_size =
+ sizeof (u32),.format_trace = format_dns46_reply_trace,.type =
+ VLIB_NODE_TYPE_INTERNAL,.n_errors =
+ ARRAY_LEN (dns46_reply_error_strings),.error_strings =
+ dns46_reply_error_strings,.n_next_nodes = DNS46_REPLY_N_NEXT,
+ /* edit / add dispositions here */
+ .next_nodes =
+ {
+ [DNS46_REPLY_NEXT_DROP] = "error-drop",}
+,};
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */