From f6eee0760ca32e8ce090d73135ffbeb483f2bc5a Mon Sep 17 00:00:00 2001

From: Stephen Baynes <sbaynes@mail.com>

Date: Thu, 1 Dec 2016 12:20:39 +1300

Subject: [PATCH] Bug 4007: Hang on DNS query with dead-end CNAME

DNS lookup recursion no longer occurs. ipcacheParse() return values are no

longer useful.

Also, cleanup the debugging output.

---

 src/ipcache.cc | 40 ++++++++++++++++------------------------

 1 file changed, 16 insertions(+), 24 deletions(-)

diff --git a/src/ipcache.cc b/src/ipcache.cc

index 0eaab11241..d2a883e29b 100644

--- a/src/ipcache.cc

+++ b/src/ipcache.cc

@@ -123,7 +123,6 @@ static void stat_ipcache_get(StoreEntry *);

 static FREE ipcacheFreeEntry;

 static IDNSCB ipcacheHandleReply;

 static int ipcacheExpiredEntry(ipcache_entry *);

-static int ipcacheParse(ipcache_entry *, const rfc1035_rr *, int, const char *error);

 static ipcache_entry *ipcache_get(const char *);

 static void ipcacheLockEntry(ipcache_entry *);

 static void ipcacheStatPrint(ipcache_entry *, StoreEntry *);

@@ -328,8 +327,7 @@ ipcacheCallback(ipcache_entry *i, int wait)

     ipcacheUnlockEntry(i);

 }

-/// \ingroup IPCacheAPI

-static int

+static void

 ipcacheParse(ipcache_entry *i, const rfc1035_rr * answers, int nr, const char *error_message)

 {

     int k;

@@ -350,25 +348,25 @@ ipcacheParse(ipcache_entry *i, const rfc1035_rr * answers, int nr, const char *e

     i->addrs.count = 0;

     if (nr < 0) {

-        debugs(14, 3, "ipcacheParse: Lookup failed '" << error_message << "' for '" << (const char *)i->hash.key << "'");

+        debugs(14, 3, "Lookup failed '" << error_message << "' for '" << (const char *)i->hash.key << "'");

         i->error_message = xstrdup(error_message);

-        return -1;

+        return;

     }

     if (nr == 0) {

-        debugs(14, 3, "ipcacheParse: No DNS records in response to '" << name << "'");

+        debugs(14, 3, "No DNS records in response to '" << name << "'");

         i->error_message = xstrdup("No DNS records");

-        return -1;

+        return;

     }

-    debugs(14, 3, "ipcacheParse: " << nr << " answers for '" << name << "'");

+    debugs(14, 3, nr << " answers for '" << name << "'");

     assert(answers);

     for (k = 0; k < nr; ++k) {

         if (Ip::EnableIpv6 && answers[k].type == RFC1035_TYPE_AAAA) {

             if (answers[k].rdlength != sizeof(struct in6_addr)) {

-                debugs(14, DBG_IMPORTANT, "ipcacheParse: Invalid IPv6 address in response to '" << name << "'");

+                debugs(14, DBG_IMPORTANT, MYNAME << "Invalid IPv6 address in response to '" << name << "'");

                 continue;

             }

             ++na;

@@ -378,7 +376,7 @@ ipcacheParse(ipcache_entry *i, const rfc1035_rr * answers, int nr, const char *e

         if (answers[k].type == RFC1035_TYPE_A) {

             if (answers[k].rdlength != sizeof(struct in_addr)) {

-                debugs(14, DBG_IMPORTANT, "ipcacheParse: Invalid IPv4 address in response to '" << name << "'");

+                debugs(14, DBG_IMPORTANT, MYNAME << "Invalid IPv4 address in response to '" << name << "'");

                 continue;

             }

             ++na;

@@ -394,14 +392,14 @@ ipcacheParse(ipcache_entry *i, const rfc1035_rr * answers, int nr, const char *e

         }

         // otherwise its an unknown RR. debug at level 9 since we usually want to ignore these and they are common.

-        debugs(14, 9, HERE << "Unknown RR type received: type=" << answers[k].type << " starting at " << &(answers[k]) );

+        debugs(14, 9, "Unknown RR type received: type=" << answers[k].type << " starting at " << &(answers[k]) );

     }

     if (na == 0) {

-        debugs(14, DBG_IMPORTANT, "ipcacheParse: No Address records in response to '" << name << "'");

+        debugs(14, DBG_IMPORTANT, MYNAME << "No Address records in response to '" << name << "'");

         i->error_message = xstrdup("No Address records");

         if (cname_found)

             ++IpcacheStats.cname_only;

-        return 0;

+        return;

     }

     i->addrs.in_addrs = static_cast<Ip::Address *>(xcalloc(na, sizeof(Ip::Address)));

@@ -419,7 +417,7 @@ ipcacheParse(ipcache_entry *i, const rfc1035_rr * answers, int nr, const char *e

             memcpy(&temp, answers[k].rdata, sizeof(struct in_addr));

             i->addrs.in_addrs[j] = temp;

-            debugs(14, 3, "ipcacheParse: " << name << " #" << j << " " << i->addrs.in_addrs[j]);

+            debugs(14, 3, name << " #" << j << " " << i->addrs.in_addrs[j]);

             ++j;

         } else if (Ip::EnableIpv6 && answers[k].type == RFC1035_TYPE_AAAA) {

@@ -430,7 +428,7 @@ ipcacheParse(ipcache_entry *i, const rfc1035_rr * answers, int nr, const char *e

             memcpy(&temp, answers[k].rdata, sizeof(struct in6_addr));

             i->addrs.in_addrs[j] = temp;

-            debugs(14, 3, "ipcacheParse: " << name << " #" << j << " " << i->addrs.in_addrs[j] );

+            debugs(14, 3, name << " #" << j << " " << i->addrs.in_addrs[j] );

             ++j;

         }

         if (ttl == 0 || (int) answers[k].ttl < ttl)

@@ -453,8 +451,6 @@ ipcacheParse(ipcache_entry *i, const rfc1035_rr * answers, int nr, const char *e

     i->expires = squid_curtime + ttl;

     i->flags.negcached = false;

-

-    return i->addrs.count;

 }

 /// \ingroup IPCacheInternal

@@ -467,13 +463,9 @@ ipcacheHandleReply(void *data, const rfc1035_rr * answers, int na, const char *e

     const int age = i->age();

     statCounter.dns.svcTime.count(age);

-    int done = ipcacheParse(i, answers, na, error_message);

-

-    /* If we have not produced either IPs or Error immediately, wait for recursion to finish. */

-    if (done != 0 || error_message != NULL) {

-        ipcacheAddEntry(i);

-        ipcacheCallback(i, age);

-    }

+    ipcacheParse(i, answers, na, error_message);

+    ipcacheAddEntry(i);

+    ipcacheCallback(i, age);

 }

 /**