Merge pull request apache#476 from solidwallofcode/edge-hostdb-restru…

…cture HostDB restructure
SolidWallOfCode · Jun 16, 2021 · 6f63e83 · 6f63e83
2 parents 8d40c20 + 4a5ec19
commit 6f63e83
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diff --git a/configs/body_factory/default/Makefile.am b/configs/body_factory/default/Makefile.am
@@ -28,6 +28,7 @@ dist_bodyfactory_DATA = \
 	connect\#dns_failed \
 	connect\#failed_connect \
 	connect\#hangup \
+	connect\#all_dead \
 	default \
 	interception\#no_host \
 	README \

diff --git a/configs/body_factory/default/connect#all_dead b/configs/body_factory/default/connect#all_dead
@@ -0,0 +1,17 @@
+<HTML>
+<HEAD>
+<TITLE>No Valid Host</TITLE>
+</HEAD>
+
+<BODY BGCOLOR="white" FGCOLOR="black">
+<H1>No Valid Host</H1>
+<HR>
+
+<FONT FACE="Helvetica,Arial"><B>
+Description: Unable to find a valid target host.
+
+The server was found but all of the addresses are marked dead and so there is
+no valid target address to which to connect. Please try again after a few minutes.
+</B></FONT>
+<HR>
+</BODY>
diff --git a/doc/developer-guide/core-architecture/hostdb.en.rst b/doc/developer-guide/core-architecture/hostdb.en.rst
@@ -0,0 +1,40 @@
+.. Licensed to the Apache Software Foundation (ASF) under one
+   or more contributor license agreements.  See the NOTICE file
+   distributed with this work for additional information
+   regarding copyright ownership.  The ASF licenses this file
+   to you 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:: ../../common.defs
+
+.. highlight:: cpp
+.. default-domain:: cpp
+
+.. _developer-doc-hostdb:
+
+HostDB
+******
+
+HostDB is a cache of DNS results. It is used to increase performance by aggregating address
+resolution across transactions.
+
+Runtime Structure
+=================
+
+DNS results are stored in a global hash table as instances of ``HostDBRecord``. Each instance
+stores the results of a single query. These records are not updated with new DNS results. Instead
+a new record instance is created and replaces the previous instance in the table. Some specific
+dynamic data is migrated from the old record to the new one, such as the failure status of the
+upstreams in the record.
+
+
diff --git a/doc/uml/host-resolve.plantuml b/doc/uml/host-resolve.plantuml
@@ -0,0 +1,24 @@
+' SPDX-License-Identifier: Apache-2.0
+' 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.
+
+@startuml
+
+hide empty description
+
+state HttpSM {
+  state do_http_server_open {
+  }
+}
+
+state HandleRequest #cyan
+state CallOSDNSLookup #cyan
+
+CallOSDNSLookup -> OSDNSLookup
+
+@enduml
+
diff --git a/example/plugins/c-api/protocol/TxnSM.c b/example/plugins/c-api/protocol/TxnSM.c
@@ -477,8 +477,8 @@ int
 state_dns_lookup(TSCont contp, TSEvent event, TSHostLookupResult host_info)
 {
   TxnSM *txn_sm = (TxnSM *)TSContDataGet(contp);
-  struct sockaddr const *q_server_addr;
-  struct sockaddr_in ip_addr;
+  struct sockaddr_storage q_server_addr;
+  struct sockaddr_in *addr;
 
   TSDebug(PLUGIN_NAME, "enter state_dns_lookup");
 
@@ -489,16 +489,16 @@ state_dns_lookup(TSCont contp, TSEvent event, TSHostLookupResult host_info)
   txn_sm->q_pending_action = NULL;
 
   /* Get the server IP from data structure TSHostLookupResult. */
-  q_server_addr = TSHostLookupResultAddrGet(host_info);
+  TSHostLookupResultAddrGet(host_info, (struct sockaddr *)&q_server_addr);
 
   /* Connect to the server using its IP. */
   set_handler(txn_sm->q_current_handler, (TxnSMHandler)&state_connect_to_server);
   TSAssert(txn_sm->q_pending_action == NULL);
-  TSAssert(q_server_addr->sa_family == AF_INET); /* NO IPv6 in this plugin */
+  TSAssert(q_server_addr.ss_family == AF_INET); /* NO IPv6 in this plugin */
+  addr = (struct sockaddr_in *)(&q_server_addr);
 
-  memcpy(&ip_addr, q_server_addr, sizeof(ip_addr));
-  ip_addr.sin_port         = txn_sm->q_server_port;
-  txn_sm->q_pending_action = TSNetConnect(contp, (struct sockaddr const *)&ip_addr);
+  addr->sin_port           = txn_sm->q_server_port;
+  txn_sm->q_pending_action = TSNetConnect(contp, (struct sockaddr const *)addr);
 
   return TS_SUCCESS;
 }

diff --git a/include/ts/ts.h b/include/ts/ts.h
@@ -1926,7 +1926,14 @@ tsapi TSReturnCode TSPortDescriptorAccept(TSPortDescriptor, TSCont);
 /* --------------------------------------------------------------------------
    DNS Lookups */
 tsapi TSAction TSHostLookup(TSCont contp, const char *hostname, size_t namelen);
-tsapi struct sockaddr const *TSHostLookupResultAddrGet(TSHostLookupResult lookup_result);
+/** Retrieve an address from the host lookup.
+ *
+ * @param lookup_result Result handle passed to event callback.
+ * @param dst Destination for copying the address.
+ * @return @c TS_SUCCESS if the address was available and copied, @c TS_ERROR otherwise.
+ */
+tsapi TSReturnCode TSHostLookupResultAddrGet(TSHostLookupResult lookup_result, struct sockaddr *dst);
+
 /* TODO: Eventually, we might want something like this as well, but it requires
    support for building the HostDBInfo struct:
    tsapi void TSHostLookupResultSet(TSHttpTxn txnp, TSHostLookupResult result);

diff --git a/include/tscore/BufferWriterForward.h b/include/tscore/BufferWriterForward.h
@@ -147,4 +147,11 @@ class BWFormat;
 
 class BufferWriter;
 
+/// Storage for debug messages.
+/// If @c bwprint is used with this, the storage is reused which minimizes allocations.
+/// E.g.
+/// @code
+
+inline thread_local std::string bw_dbg;
+
 } // namespace ts
diff --git a/include/tscore/Diags.h b/include/tscore/Diags.h
@@ -159,6 +159,15 @@ extern inkcoreapi Diags *diags;
     }                                                         \
   } while (0)
 
+#define Debug_bw(tag, fmt, ...)                                                             \
+  do {                                                                                      \
+    if (unlikely(diags->on())) {                                                            \
+      static const SourceLocation loc = MakeSourceLocation();                               \
+      static LogMessage log_message;                                                        \
+      log_message.debug(tag, loc, "%s", ts::bwprint(ts::bw_dbg, fmt, __VA_ARGS__).c_str()); \
+    }                                                                                       \
+  } while (0)
+
 /** Same as Debug above, but this allows a positive override of the tag
  * mechanism by a flag boolean.
  *

diff --git a/include/tscore/bwf_std_format.h b/include/tscore/bwf_std_format.h
@@ -26,6 +26,7 @@
 #include <atomic>
 #include <array>
 #include <string_view>
+#include <chrono>
 #include "tscpp/util/TextView.h"
 #include "tscore/BufferWriterForward.h"
 
@@ -37,6 +38,21 @@ bwformat(ts::BufferWriter &w, ts::BWFSpec const &spec, atomic<T> const &v)
 {
   return ts::bwformat(w, spec, v.load());
 }
+
+template <typename Rep, typename Period>
+ts::BufferWriter &
+bwformat(ts::BufferWriter &w, ts::BWFSpec const &spec, chrono::duration<Rep, Period> const &d)
+{
+  return bwformat(w, spec, d.count());
+}
+
+template <typename Clock, typename Duration>
+ts::BufferWriter &
+bwformat(ts::BufferWriter &w, ts::BWFSpec const &spec, chrono::time_point<Clock, Duration> const &t)
+{
+  return bwformat(w, spec, t.time_since_epoch());
+}
+
 } // end namespace std
 
 namespace ts

diff --git a/include/tscore/ink_inet.h b/include/tscore/ink_inet.h
@@ -1231,6 +1231,16 @@ struct IpAddr {
                  size_t len  ///< [in] Size of buffer.
   ) const;
 
+  /** Write the address to a socket address.
+   *
+   * @param dest Socket address to update.
+   * @return @a dest
+   *
+   * The address and family are updated. The port is unchanged. @a dest is assumed to be the
+   * appropriate underlying type for the family of @a this.
+   */
+  sockaddr *toSockAddr(sockaddr *dest) const;
+
   /// Equality.
   bool
   operator==(self const &that) const

diff --git a/include/tscore/ink_time.h b/include/tscore/ink_time.h
@@ -33,6 +33,8 @@
 
 #pragma once
 
+#include <chrono>
+
 #include "tscore/ink_platform.h"
 #include "tscore/ink_defs.h"
 #include "tscore/ink_hrtime.h"
@@ -43,7 +45,17 @@
 
  *===========================================================================*/
 
-typedef time_t ink_time_t;
+using ink_time_t  = time_t;
+using ts_clock    = std::chrono::system_clock;
+using ts_time     = ts_clock::time_point;
+using ts_hr_clock = std::chrono::high_resolution_clock;
+using ts_hr_time  = ts_hr_clock::time_point;
+
+using ts_seconds      = std::chrono::seconds;
+using ts_milliseconds = std::chrono::milliseconds;
+
+/// Equivalent of 0 for @c ts_time. This should be used as the default initializer.
+static constexpr ts_time TS_TIME_ZERO;
 
 /*===========================================================================*
 

diff --git a/include/tscore/ts_file.h b/include/tscore/ts_file.h
@@ -329,5 +329,12 @@ namespace file
 
   /* ------------------------------------------------------------------- */
 } // namespace file
+
+inline BufferWriter &
+bwformat(BufferWriter &w, BWFSpec const &spec, file::path const &path)
+{
+  return bwformat(w, spec, path.string());
+}
+
 } // namespace ts
 /* ------------------------------------------------------------------- */
diff --git a/include/tscpp/util/TextView.h b/include/tscpp/util/TextView.h
@@ -65,6 +65,29 @@ int strcasecmp(const std::string_view &lhs, const std::string_view &rhs);
  */
 int memcmp(const std::string_view &lhs, const std::string_view &rhs);
 
+/** Copy bytes.
+ *
+ * @param dst Destination buffer.
+ * @param src Original string.
+ * @return @a dest
+ *
+ * This is a convenience for
+ * @code
+ *   memcpy(dst, src.data(), size.size());
+ * @endcode
+ * Therefore @a dst must point at a buffer large enought to hold @a src. If this is not already
+ * determined, then presuming @c DST_SIZE is the size of the buffer at @a dst
+ * @code
+ *   memcpy(dst, src.prefix(DST_SIZE));
+ * @endcode
+ *
+ */
+inline void *
+memcpy(void *dst, const std::string_view &src)
+{
+  return memcpy(dst, src.data(), src.size());
+}
+
 /** Compare views with ordering.
  *
  * @param lhs input view

diff --git a/iocore/dns/DNS.cc b/iocore/dns/DNS.cc
@@ -400,7 +400,7 @@ DNSProcessor::DNSProcessor()
 }
 
 void
-DNSEntry::init(const char *x, int len, int qtype_arg, Continuation *acont, DNSProcessor::Options const &opt)
+DNSEntry::init(DNSQueryData target, int qtype_arg, Continuation *acont, DNSProcessor::Options const &opt)
 {
   qtype          = qtype_arg;
   host_res_style = opt.host_res_style;
@@ -427,21 +427,16 @@ DNSEntry::init(const char *x, int len, int qtype_arg, Continuation *acont, DNSPr
   mutex = dnsH->mutex;
 
   if (is_addr_query(qtype) || qtype == T_SRV) {
-    if (len) {
-      len = len > (MAXDNAME - 1) ? (MAXDNAME - 1) : len;
-      memcpy(qname, x, len);
-      qname[len]     = 0;
-      orig_qname_len = qname_len = len;
-    } else {
-      qname_len      = ink_strlcpy(qname, x, MAXDNAME);
-      orig_qname_len = qname_len;
-    }
+    auto name = target.name.substr(0, MAXDNAME); // be sure of safe copy into @a qname
+    memcpy(qname, name);
+    qname[name.size()] = '\0';
+    orig_qname_len = qname_len = name.size();
   } else { // T_PTR
-    IpAddr const *ip = reinterpret_cast<IpAddr const *>(x);
-    if (ip->isIp6()) {
-      orig_qname_len = qname_len = make_ipv6_ptr(&ip->_addr._ip6, qname);
-    } else if (ip->isIp4()) {
-      orig_qname_len = qname_len = make_ipv4_ptr(ip->_addr._ip4, qname);
+    auto addr = target.addr;
+    if (addr->isIp6()) {
+      orig_qname_len = qname_len = make_ipv6_ptr(&addr->_addr._ip6, qname);
+    } else if (addr->isIp4()) {
+      orig_qname_len = qname_len = make_ipv4_ptr(addr->_addr._ip4, qname);
     } else {
       ink_assert(!"T_PTR query to DNS must be IP address.");
     }
@@ -1305,15 +1300,20 @@ DNSEntry::mainEvent(int event, Event *e)
 }
 
 Action *
-DNSProcessor::getby(const char *x, int len, int type, Continuation *cont, Options const &opt)
+DNSProcessor::getby(DNSQueryData x, int type, Continuation *cont, Options const &opt)
 {
-  Debug("dns", "received query %s type = %d, timeout = %d", x, type, opt.timeout);
-  if (type == T_SRV) {
-    Debug("dns_srv", "DNSProcessor::getby attempting an SRV lookup for %s, timeout = %d", x, opt.timeout);
+  if (type == T_PTR) {
+    Debug("dns", "received reverse query type = %d, timeout = %d", type, opt.timeout);
+  } else {
+    Debug("dns", "received query %.*s type = %d, timeout = %d", int(x.name.size()), x.name.data(), type, opt.timeout);
+    if (type == T_SRV) {
+      Debug("dns_srv", "DNSProcessor::getby attempting an SRV lookup for %.*s, timeout = %d", int(x.name.size()), x.name.data(),
+            opt.timeout);
+    }
   }
   DNSEntry *e = dnsEntryAllocator.alloc();
   e->retries  = dns_retries;
-  e->init(x, len, type, cont, opt);
+  e->init(x, type, cont, opt);
   MUTEX_TRY_LOCK(lock, e->mutex, this_ethread());
   if (!lock.is_locked()) {
     thread->schedule_imm(e);