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authorbrain <brain@e03df62e-2008-0410-955e-edbf42e46eb7>2006-07-20 16:48:44 +0000
committerbrain <brain@e03df62e-2008-0410-955e-edbf42e46eb7>2006-07-20 16:48:44 +0000
commit57bba0c632bf07cdce7810330dffdfa27ae14972 (patch)
tree76e3933845ab49250fe889306c6a394a705d54d5
parentcd146649029d2d6d2a5edd804d2e6a31e13593bc (diff)
Make threaded dns stable by placing some mutexes around some stl stuff (this really needs lots of testing now)
git-svn-id: http://svn.inspircd.org/repository/trunk/inspircd@4460 e03df62e-2008-0410-955e-edbf42e46eb7
-rw-r--r--src/dns.cpp60
-rw-r--r--src/dnsqueue.cpp2
-rw-r--r--src/users.cpp6
3 files changed, 57 insertions, 11 deletions
diff --git a/src/dns.cpp b/src/dns.cpp
index aaa6bf89e..a6e413071 100644
--- a/src/dns.cpp
+++ b/src/dns.cpp
@@ -53,9 +53,14 @@ using namespace std;
#include "socketengine.h"
#include "configreader.h"
+#ifdef THREADED_DNS
+pthread_mutex_t connmap_lock = PTHREAD_MUTEX_INITIALIZER;
+#endif
+
extern InspIRCd* ServerInstance;
extern ServerConfig* Config;
extern time_t TIME;
+extern userrec* fd_ref_table[MAX_DESCRIPTORS];
enum QueryType { DNS_QRY_A = 1, DNS_QRY_PTR = 12 };
enum QueryFlags1 { FLAGS1_MASK_RD = 0x01, FLAGS1_MASK_TC = 0x02, FLAGS1_MASK_AA = 0x04, FLAGS1_MASK_OPCODE = 0x78, FLAGS1_MASK_QR = 0x80 };
@@ -287,10 +292,15 @@ s_connection *dns_add_query(s_header *h)
return NULL;
}
/* create new connection object, add to linked list */
+#ifdef THREADED_DNS
+ pthread_mutex_lock(&connmap_lock);
+#endif
if (connections.find(s->fd) == connections.end())
connections[s->fd] = s;
+#ifdef THREADED_DNS
+ pthread_mutex_unlock(&connmap_lock);
+#endif
- lastcreate = s->fd;
return s;
}
@@ -453,6 +463,14 @@ char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS
*res = 0;
/* FireDNS used a linked list for this. How ugly (and slow). */
+
+#ifdef THREADED_DNS
+ /* XXX: STL really does NOT like being poked and prodded in more than
+ * one orifice by threaded apps. Make sure we remain nice to it, and
+ * lock a mutex around any access to the std::map.
+ */
+ pthread_mutex_lock(&connmap_lock);
+#endif
connlist_iter n_iter = connections.find(cfd);
if (n_iter == connections.end())
{
@@ -466,6 +484,9 @@ char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS
/* We don't delete c here, because its done later when needed */
connections.erase(n_iter);
}
+#ifdef THREADED_DNS
+ pthread_mutex_unlock(&connmap_lock);
+#endif
l = recv(c->fd,buffer,sizeof(s_header),0);
dns_close(c->fd);
@@ -838,6 +859,20 @@ std::string DNS::GetResultIP()
#ifdef THREADED_DNS
+
+/* This function is a thread function which can be thought of as a lightweight process
+ * to all you non-threaded people. In actuality its so much more, and pretty damn cool.
+ * With threaded dns enabled, each user which connects gets a thread attached to their
+ * user record when their DNS lookup starts. This function starts in parallel, and
+ * commences a blocking dns lookup. Because its a seperate thread, this occurs without
+ * actually blocking the main application. Once the dns lookup is completed, the thread
+ * checks if the user is still around by checking their fd against the reference table,
+ * and if they are, writes the hostname into the struct and terminates, after setting
+ * userrec::dns_done to true. Because this is multi-threaded it can make proper use of
+ * SMP setups (like the one i have here *grin*).
+ * This is in comparison to the non-threaded dns, which must monitor the thread sockets
+ * in a nonblocking fashion, consuming more resources to do so.
+ */
void* dns_task(void* arg)
{
userrec* u = (userrec*)arg;
@@ -848,30 +883,33 @@ void* dns_task(void* arg)
DNS dns2;
std::string host;
std::string ip;
- if (dns1.ReverseLookup((char*)inet_ntoa(u->ip4)))
+ if (dns1.ReverseLookup(inet_ntoa(u->ip4),false))
{
while (!dns1.HasResult())
- {
usleep(100);
- }
host = dns1.GetResult();
if (host != "")
{
- if (dns2.ForwardLookup(host), false)
+ if (dns2.ForwardLookup(host, false))
{
while (!dns2.HasResult())
- {
usleep(100);
- }
ip = dns2.GetResultIP();
if (ip == std::string(inet_ntoa(u->ip4)))
{
- if (host.length() < 160)
+ if (host.length() < 65)
{
if ((fd_ref_table[thisfd] == u) && (fd_ref_table[thisfd]))
- strcpy(u->host,host.c_str());
- if ((fd_ref_table[thisfd] == u) && (fd_ref_table[thisfd]))
- strcpy(u->dhost,host.c_str());
+ {
+ if (!u->dns_done)
+ {
+ strcpy(u->host,host.c_str());
+ if ((fd_ref_table[thisfd] == u) && (fd_ref_table[thisfd]))
+ {
+ strcpy(u->dhost,host.c_str());
+ }
+ }
+ }
}
}
}
diff --git a/src/dnsqueue.cpp b/src/dnsqueue.cpp
index a3a558823..35dc1bba1 100644
--- a/src/dnsqueue.cpp
+++ b/src/dnsqueue.cpp
@@ -239,6 +239,7 @@ bool lookup_dns(const std::string &nick)
void ZapThisDns(int fd)
{
+#ifndef THREADED_DNS
if ((fd < 0) || (fd > MAX_DESCRIPTORS))
return;
@@ -258,6 +259,7 @@ void ZapThisDns(int fd)
dns_close(x->resolver2.GetFD());
}
}
+#endif
}
void dns_poll(int fdcheck)
diff --git a/src/users.cpp b/src/users.cpp
index bf99c1fc8..689ed3bf4 100644
--- a/src/users.cpp
+++ b/src/users.cpp
@@ -219,6 +219,12 @@ userrec::~userrec()
ucrec* x = (ucrec*)*n;
delete x;
}
+#ifdef THREADED_DNS
+ if ((!dns_done) && (registered >= 3))
+ {
+ pthread_kill(this->dnsthread, SIGTERM);
+ }
+#endif
}
/* XXX - minor point, other *Host functions return a char *, this one creates it. Might be nice to be consistant? */