TCP: Source address is from routing table not from -i flag

[hamzasheikh]

Short Description

When using "-t tn" and "-i myip" the IP used to send messages is not myip but the IP from the OS (Linux) routing table.

Also filed the same bug on SourceForge: Issue 147. Posted on mailing list as well.

Steps to Reproduce

On the "server" side start netcat

nc -v -l 10.10.0.55 5060

On the "client" side run built-in UAC scenario using -t tn and -i myip

sipp -sn uac -i 10.10.0.5 -t tn -p 5060 -m 1 -r 1 -trace_msg -message_file run.msg -trace_stat -stf run.stat -trace_err -trace_screen -error_file run.err -send_timeout 5000 -recv_timeout 5000 10.10.0.55

On the "server" side you'll see something like this on the output on netcat

Connection from 10.10.0.4 port 5060 [tcp/*] accepted
INVITE sip:service@10.10.0.55:5060 SIP/2.0
Via: SIP/2.0/TCP 10.10.0.5:5060;branch=z9hG4bK-2202-1-0
From: sipp <sip:sipp@10.10.0.5:5060>;tag=2202SIPpTag001
To: service <sip:service@10.10.0.55:5060>
Call-ID: 1-2202@10.10.0.5
CSeq: 1 INVITE
Contact: sip:sipp@10.10.0.5:5060
Max-Forwards: 70
Subject: Performance Test
Content-Type: application/sdp
Content-Length:   129

v=0
o=user1 53655765 2353687637 IN IP4 10.10.0.5
s=-
c=IN IP4 10.10.0.5
t=0 0
m=audio 6000 RTP/AVP 0
a=rtpmap:0 PCMU/8000

Observed Result

If you look at the first line of the nc output it says the connection is from 10.10.0.4 instead of 10.10.0.5 (the IP we provided with the -i flag).

I have also tried -ci flag with the same result.

If I use -t un flag then the first line of output of nc is "Connection from 10.10.0.5 port 5060 [udp/*] accepted".

Expected Result

The IP 10.10.0.5 should be used whether -t is tn or un when making connections.

Client Environment

aikchar@opensuse:~/sipp/run> ip a s
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 brd 127.255.255.255 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:50:56:01:c5:95 brd ff:ff:ff:ff:ff:ff
    inet 10.145.194.238/18 brd 10.145.255.255 scope global ens32
       valid_lft forever preferred_lft forever
    inet6 fe80::250:56ff:fe01:c595/64 scope link 
       valid_lft forever preferred_lft forever
3: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:50:56:01:c5:96 brd ff:ff:ff:ff:ff:ff
    inet 10.10.0.4/22 brd 10.10.3.255 scope global ens33
       valid_lft forever preferred_lft forever
    inet 10.10.0.5/22 brd 10.10.3.255 scope global secondary ens33:add1
       valid_lft forever preferred_lft forever
    inet6 fe80::250:56ff:fe01:c596/64 scope link 
       valid_lft forever preferred_lft forever
4: ens34: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:50:56:01:c5:97 brd ff:ff:ff:ff:ff:ff
    inet 10.20.0.4/22 brd 10.20.3.255 scope global ens34
       valid_lft forever preferred_lft forever
    inet6 fe80::250:56ff:fe01:c597/64 scope link 
       valid_lft forever preferred_lft forever

aikchar@opensuse:~/sipp/run> ip r s
default via 10.145.255.254 dev ens32 
10.10.0.0/22 dev ens33  proto kernel  scope link  src 10.10.0.4 
10.20.0.0/22 dev ens34  proto kernel  scope link  src 10.20.0.4 
10.145.192.0/18 dev ens32  proto kernel  scope link  src 10.145.194.238 
127.0.0.0/8 dev lo  scope link

Server Environment

[aikchar@centos ~]$ ip a s
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:50:56:01:c3:96 brd ff:ff:ff:ff:ff:ff
    inet 10.145.194.226/18 brd 10.145.255.255 scope global eth0
    inet6 fe80::250:56ff:fe01:c396/64 scope link 
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:50:56:01:c3:97 brd ff:ff:ff:ff:ff:ff
    inet 10.10.0.2/22 brd 10.10.3.255 scope global eth1
    inet 10.10.0.51/22 scope global secondary eth1:1
    inet 10.10.0.52/22 scope global secondary eth1:2
    inet 10.10.0.53/22 scope global secondary eth1:3
    inet 10.10.0.54/22 scope global secondary eth1:4
    inet 10.10.0.55/22 scope global secondary eth1:5
    inet 10.10.0.56/22 scope global secondary eth1:6
    inet 10.10.0.57/22 scope global secondary eth1:7
    inet 10.10.0.58/22 scope global secondary eth1:8
    inet 10.10.0.59/22 scope global secondary eth1:9
    inet 10.10.0.60/22 scope global secondary eth1:10
    inet 10.10.0.61/22 scope global secondary eth1:11
    inet 10.10.0.62/22 scope global secondary eth1:12
    inet 10.10.0.63/22 scope global secondary eth1:13
    inet 10.10.0.64/22 scope global secondary eth1:14
    inet 10.10.0.65/22 scope global secondary eth1:15
    inet 10.10.0.66/22 scope global secondary eth1:16
    inet 10.10.0.67/22 scope global secondary eth1:17
    inet 10.10.0.68/22 scope global secondary eth1:18
    inet 10.10.0.69/22 scope global secondary eth1:19
    inet 10.10.0.70/22 scope global secondary eth1:20
    inet6 2002::10:10:0:64/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:63/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:62/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:61/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:60/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:5f/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:5e/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:5d/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:5c/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:5b/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:5a/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:59/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:58/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:57/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:56/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:55/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:54/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:53/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:52/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 2002::10:10:0:51/96 scope global 
       valid_lft forever preferred_lft forever
    inet6 fe80::250:56ff:fe01:c397/64 scope link 
       valid_lft forever preferred_lft forever
4: eth2: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:50:56:01:c3:98 brd ff:ff:ff:ff:ff:ff
5: ip6tnl0: <NOARP> mtu 1460 qdisc noop 
    link/tunnel6 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00 brd 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00

[aikchar@centos ~]$ ip r s
10.10.0.0/22 dev eth1  proto kernel  scope link  src 10.10.0.2 
10.20.0.0/22 via 10.10.0.1 dev eth1 
10.145.192.0/18 dev eth0  proto kernel  scope link  src 10.145.194.226 
169.254.0.0/16 dev eth0  scope link  metric 1002 
169.254.0.0/16 dev eth1  scope link  metric 1003 
169.254.0.0/16 dev eth2  scope link  metric 1004 
default via 10.145.255.254 dev eth0

SIPp Version

The version of SIPp tried:

aikchar@opensuse:~/sipp/run> sipp -v
SIPp v3.3-TLS-SCTP-PCAP, built Jun 23 2013, 00:25:41.
...

Workaround

A workaround I found was to add a SNAT rule to iptables to re-write the IP address. You may need to change the values according to your environment.

iptables -t nat -A POSTROUTING -o eth0 -p tcp ! --sport 5060 -d 192.168.1.21 --dport 5060 -j SNAT --to-source 192.168.1.15

You can delete this rule when not needed.

iptables -t nat -D POSTROUTING -o eth0 -p tcp ! --sport 5060 -d 192.168.1.21 --dport 5060 -j SNAT --to-source 192.168.1.15

[wdoekes]

Please try https://github.com/SIPp/sipp/tree/fix/tcp_bind/issue83.

[hamzasheikh]

Result

With this fix SIPp sends traffic using the IP address specified with the -i flag for both TCP and UDP. I confirmed it using Wireshark with the v3.3 binary and my private binary (with this fix).

Issue Observed

I saw one issue when using -t tn versus -t t1 and -t un versus -t u1.

 sipp -i 10.10.0.62 10.20.0.55 -t tn -p 5060 -inf /tmp/cs1_10-10-0-52_15068.inf.csv -trace_msg -message_file /tmp/cs1_10-10-0-52_15068.msg -trace_stat -stf /tmp/cs1_10-10-0-52_15068.stat.csv -trace_err -trace_screen -error_file /tmp/cs1_10-10-0-52_15068.err -r 1 -send_timeout 5000 -recv_timeout 5000 -m 1

Using -t tn or -t un caused SIPp to fail to start with the following message when using the binary I compiled from the source code with this fix. SIPp started just fine using the v3.3 binary I was previously using.

2014-08-06 15:19:48.351460 1407363588.351460: Maximum number of open sockets (50000) should be less than the maximum number of open files (1024). Tune this with the ulimit command or the -max_socket option.

With both v3.3 and my private binary, SIPp ran fine with -t t1 or -t u1, as below:

 sipp -i 10.10.0.62 10.20.0.55 -t t1 -p 5060 -inf /tmp/cs1_10-10-0-52_15068.inf.csv -trace_msg -message_file /tmp/cs1_10-10-0-52_15068.msg -trace_stat -stf /tmp/cs1_10-10-0-52_15068.stat.csv -trace_err -trace_screen -error_file /tmp/cs1_10-10-0-52_15068.err -r 1 -send_timeout 5000 -recv_timeout 5000 -m 1

Compile Problems

I was compiling the source with the fix for this issue on CentOS 6.4 (64-bit) as well as CentOS 5.10 (32-bit) and ran into two problems.

I am not experienced enough with C and compiling to know what effect my workarounds had. Maybe they contributed to the issue I observed with -t tn; I can't say for sure.

Problem 1

During ./configure I got the following error:

./configure: line 10602: syntax error near unexpected token AX_CONFIG_FEATURE_ENABLE' ./configure: line 10602: AX_HAVE_EPOLL(AX_CONFIG_FEATURE_ENABLE(epoll),'

I made the error go away by commenting out the offending lines and replacing them with:

HAVE_EPOLL_TRUE=
HAVE_EPOLL_FALSE='#'

Problem 2

During make I got the following errors.

src/sipp-time.o: In function getmicroseconds()': /chroot/root/sipp/src/time.cpp:57: undefined reference toclock_gettime'

I got rid of them by running ./configure and make this way:

LDFLAGS=" -lrt "  ./configure --with-openssl --with-pcap --with-sctp --with-rtpstream
LDFLAGS=" -lrt "  make

Thank You

Thank you for looking into this issue and providing a fix so quickly. Looking forward to getting this fix in the next release so my team and I can upgrade to it on all our setups.

[wdoekes]

The maximum number of open sockets error you saw was because of this commit: 84d01c8 (Sat Feb 1 23:56:51 2014 +0000, new in 3.4)
You get the same error for both -t un and -t tn, unless you decrease -max_socket.

It's not a bug but a feature.

[wdoekes]

Problem 1: did you run aclocal and friends? Of a different version? There is no line 10602 in the supplied configure. You should generally run build.sh, which touches the supplied files so you don't need to rebuild configure.

[wdoekes]

Problem 2: fixed in 544abe4.

Thanks for the detailed reports.

[wdoekes]

@vodik: f2e4d3e broke this, according to the regression tests:

Testing github-#0083-1: failed
Testing github-#0083-2: unexpected success

Note that the github-#0083-2 success is worth nothing when github-#0083-1 fails.

[wdoekes]

Possible fix -- which unfortunately breaks other regression tests. This needs better testing facilities:

diff --git a/regress/github-#0083-1/run b/regress/github-#0083-1/run
index 488481a..1ee7991 100755
--- a/regress/github-#0083-1/run
+++ b/regress/github-#0083-1/run
@@ -9,8 +9,10 @@ sleep 1
 sippbg -m 1 -sn uac -i 127.0.3.1 -t t1 -p 5071 127.0.2.1:5070
 kill -9 $pid

+# It'd be best if tcp src was 127.0.3.1:5071, but see github-#98.
 if grep -q '^Connection from 127.0.3.1:' tmp.log; then
     ok
 else
-    fail
+    got=`sed -e '/^Connection from/!d;s/.*from //' tmp.log`
+    fail "expected tcp src 127.0.3.1:*, got $got"
 fi
diff --git a/regress/github-#0083-2/run b/regress/github-#0083-2/run
index 88802ea..c8085c8 100755
--- a/regress/github-#0083-2/run
+++ b/regress/github-#0083-2/run
@@ -12,41 +12,7 @@ kill -9 $pid
 conn_sport=`sed -ne 's/^Connection from.*://p' tmp.log`
 via_sport=`grep ^Via: tmp.log | sed -e 's/.*:\([0-9]*\);.*/\1/'`
 if test $conn_sport = $via_sport; then
-    unexpected_ok
+    ok
 else
-    expected_fail
+    fail "expected $via_port and $conn_port to be equal"
 fi
-
-
-# This is disabled, because it broke github-#0098.
-#
-# From 807a97fc3ef97811c393266ce57ff8c5afd185d9 Mon Sep 17 00:00:00 2001
-# From: Walter Doekes <walter+github@wjd.nu>
-# Date: Wed, 6 Aug 2014 09:30:48 +0200
-# Subject: [PATCH] Also update local_port value after binding a TCP socket.
-# 
-# The [local_port] will hold the random port that was bound to.
-# ---
-#  src/socket.cpp | 3 +--
-#  1 file changed, 1 insertion(+), 2 deletions(-)
-# 
-# diff --git a/src/socket.cpp b/src/socket.cpp
-# index 9214a2d..74c77b6 100644
-# --- a/src/socket.cpp
-# +++ b/src/socket.cpp
-# @@ -1520,14 +1520,13 @@ int sipp_do_connect_socket(struct sipp_socket *socket)
-#  
-#      if (socket->ss_transport == T_TCP || socket->ss_transport == T_TLS) {
-#          struct sockaddr_storage local_without_port;
-# -        int port = -1;
-#          memcpy(&local_without_port, &local_sockaddr, sizeof(struct sockaddr_storage));
-#          if (local_ip_is_ipv6) {
-#              (_RCAST(struct sockaddr_in6 *, &local_without_port))->sin6_port = htons(0);
-#          } else {
-#              (_RCAST(struct sockaddr_in *, &local_without_port))->sin_port = htons(0);
-#          }
-# -        sipp_bind_socket(socket, &local_without_port, &port);
-# +        sipp_bind_socket(socket, &local_without_port, &local_port);
-#      }
-#  #ifdef USE_SCTP
-#      if (socket->ss_transport == T_SCTP) {
diff --git a/src/socket.cpp b/src/socket.cpp
index e3004c5..3fb276c 100644
--- a/src/socket.cpp
+++ b/src/socket.cpp
@@ -2515,7 +2515,7 @@ int open_connections()
         memset(&local_sockaddr, 0, sizeof(struct sockaddr_storage));
         local_sockaddr.ss_family = local_addr->ai_addr->sa_family;

-        if (!strlen(local_ip)) {
+        if (local_ip[0] == '\0') {
             get_inet_address(_RCAST(struct sockaddr_storage*, local_addr->ai_addr),
                 local_ip, sizeof(local_ip));
         } else {
@@ -2529,8 +2529,10 @@ int open_connections()
         if (local_sockaddr.ss_family == AF_INET6) {
             local_ip_is_ipv6 = true;
             sprintf(local_ip_escaped, "[%s]", local_ip);
+            inet_pton(AF_INET6, local_ip, &((struct sockaddr_in6*)&local_sockaddr)->sin6_addr);
         } else {
             strcpy(local_ip_escaped, local_ip);
+            inet_pton(AF_INET, local_ip, &((struct sockaddr_in*)&local_sockaddr)->sin_addr);
         }
     }

@@ -2732,10 +2734,14 @@ int open_connections()

             if (tcp_multiplex->ss_ipv6) {
                 struct sockaddr_in6 sa_loc = {AF_INET6};
+                memcpy(&sa_loc.sin6_addr, &((struct sockaddr_in6*)&local_sockaddr)->sin6_addr,
+                       sizeof(struct in6_addr));
                 sa_loc.sin6_port = htons(local_port);
                 sipp_bind_socket(tcp_multiplex, (struct sockaddr_storage*)&sa_loc, NULL);
             } else {
                 struct sockaddr_in sa_loc = {AF_INET};
+                memcpy(&sa_loc.sin_addr, &((struct sockaddr_in*)&local_sockaddr)->sin_addr,
+                       sizeof(struct in_addr));
                 sa_loc.sin_port = htons(local_port);
                 sipp_bind_socket(tcp_multiplex, (struct sockaddr_storage*)&sa_loc, NULL);
             }