Re: [evlog-dev] [Bug] fail to connect to the remote consolidator host when using IP address which cannot be resolved by dns

Hi Yi,

Thanks for reporting this. Our intention is even if you enter an IP address
in the .conf file, it has to be resolved back to the hostname via the DNS
or /etc/hosts file.
 We will make sure that it will be documented in the INSTALL.

Thanks, Hien.
Hien Nguyen
[email protected]
(503) 578-4347


|---------+-------------------------------------------->
|         |           "Zhu, Yi" <[email protected]>     |
|         |           Sent by:                         |
|         |           [email protected]|
|         |           ceforge.net                      |
|         |                                            |
|         |                                            |
|         |           12/18/2002 01:50 AM              |
|         |                                            |
|---------+-------------------------------------------->
  >-----------------------------------------------------------------------------------------------|
  |                                                                                               |
  |       To:       "'[email protected]'"                                    |
  |        <[email protected]>                                               |
  |       cc:                                                                                     |
  |       Subject:  [evlog-dev] [Bug] fail to connect to the remote consolidator host when using  |
  |        IP address which cannot be resolved by dns                                             |
  |                                                                                               |
  |                                                                                               |
  >-----------------------------------------------------------------------------------------------|



Hi,

When I setup evlog 1.5 to use the TCP plug-in forwarding events feature, I
found my source host cannot connect to the remote consolidator host. I
debuged the code by setting DEBUG2 to gcc and finally found out the reason.
It is because I use IP address in file
/etc/evlog.d/plugins/tcp_rmtlog_be.conf, but I didn't setup my machine to
be
recognized by the dns server or in the source host's /etc/hosts. So the
plug-in code will return -1 (tcp_rmtlog_be.c:90) because gethostbyaddr()
returns NULL (tcp_rmtlog_be.c:82). I don't think it is necessary to use
gethostbyaddr() if it is a IP address, otherwise it should be documented in
INSTALL file to tell people adding the remote consolidator host in the
source host's /etc/hosts, right? The same thing happens for UDP.

Below is my fix for the bug.

diff -Naur evlog/user/cmd/evlogd/tcp_rmtlog_be/tcp_rmtlog_be.c
evlog-new/user/cmd/evlogd/tcp_rmtlog_be/tcp_rmtlog_be.c
--- evlog/user/cmd/evlogd/tcp_rmtlog_be/tcp_rmtlog_be.c
2002-12-14 03:26:01.
000000000 +0800
+++ evlog-new/user/cmd/evlogd/tcp_rmtlog_be/tcp_rmtlog_be.c
2002-12-18
17:52:04.000000000 +0800
@@ -79,10 +79,11 @@
             }
             /* get host name/ip address */
             if (inet_aton(rmt_hostname, &inaddr)) {
-                        rmthost = (struct hostent *) gethostbyaddr((char
*) &inaddr,
sizeof(inaddr), AF_INET);
+                        address.sin_addr.s_addr = inet_addr
(rmt_hostname);
             }
             else {
                         rmthost = (struct hostent *)
gethostbyname(rmt_hostname);
+                        memcpy(&address.sin_addr, rmthost->h_addr_list[0],
rmthost->h_length);
             }

             if (!rmthost) {
@@ -99,8 +100,6 @@
             address.sin_family = AF_INET;
             address.sin_port = htons(evl_port);

-            memcpy(&address.sin_addr, rmthost->h_addr_list[0],
rmthost->h_length);
-
             if(connect(fd, (struct sockaddr *) &address, sizeof(address))
!= 0)
{
                         TRACE("Failed to connect to remote server.\n");
                         close(fd);
diff -Naur evlog/user/cmd/evlogd/udp_rmtlog_be/udp_rmtlog_be.c
evlog-new/user/cmd/evlogd/udp_rmtlog_be/udp_rmtlog_be.c
--- evlog/user/cmd/evlogd/udp_rmtlog_be/udp_rmtlog_be.c
2002-12-12 02:58:57.
000000000 +0800
+++ evlog-new/user/cmd/evlogd/udp_rmtlog_be/udp_rmtlog_be.c
2002-12-18
17:52:05.000000000 +0800
@@ -64,10 +64,11 @@
             }
             /* get host name/ip address */
             if (inet_aton(rmt_hostname, &inaddr)) {
-                        rmthost = (struct hostent *) gethostbyaddr((char
*) &inaddr,
sizeof(inaddr), AF_INET);
+                        address.sin_addr.s_addr = inet_addr
(rmt_hostname);
             }
             else {
                         rmthost = (struct hostent *)
gethostbyname(rmt_hostname);
+                        memcpy(&address.sin_addr, rmthost->h_addr_list[0],
rmthost->h_length);
             }

             if (!rmthost) {
@@ -89,8 +90,6 @@
             address.sin_family = AF_INET;
             address.sin_port = htons(evl_port);

-            memcpy(&address.sin_addr, rmthost->h_addr_list[0],
rmthost->h_length);
-
             return 0;
 }

Thanks,
----------------------------------------------------------------------------

----------------------------------------------------
Opinions expressed are those of the author and do not represent Intel Corp.

Zhu Yi (Chuyee)
Intel China Software Lab (ICSL)
22nd Floor, ShanghaiMart Tower No. 2299 Yan'an Road(West) Shanghai 200336,
PRC
Tel: 8621-52574545-1261 Fax: 8621-62366119

GnuPG v1.0.6 (GNU/Linux)
http://cn.geocities.com/chewie_chuyee/gpg.txt
1024D/71C34820 C939 2B0B FBCE 1D51 109A  55E5 8650 DB90 71C3 4820


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