I am trying to implement a monitoring system using ONOS. I am able to collect the port delta statistics from them using port_stat_changed listener.
In the flow statistics, I get the flow entry, which has selection criterion. This criterion only has only Ethernet information. Is there any way to identify the Source and Destination IP address and Port using ONOS. Any suggestion would be very helpful.
The source and destination IP and MAC if they are not in the Switch's rules can be accessed by the application by taking this information from the packets. If your application does not have access to the packages, I do not think the Switches store this kind of information. In case, then, you're going to have to develop a solution by putting a rule in the Switch to pick up that data.
This probably has a very obvious answer, but what is the common way to get the router/gateway IP address of the packet I just received in pcap.net?
I know how to get the IP address source:
packet.Ethernet.IpV4.Source.ToString()
I tried looking through the object browser, but I didn't find a property that seemed to match. Any way I could find it?
It's more of networking question, than programming one. A short answer would be - You can't.
The source IP address will always (unless strangely translated by the gateway) belong to the endpoint You wanted to connect with. This way Your application will get the response to any request You send. Unless You're using NAT the router does not alter the packet in any way so it's transparent from a connectivity point of view. The source address of the packet You just got would almost always contain the IP address of the server You connected to. That's the way Ethernet works.
A poor man's solution would be to use traceroute to find out which way the packets go and therefore get the address of the router, which generally would be the first hop along the way. From a programmer's perspective this would mean sending out several packets to the destination You got the packet from, each time incrementing the packet's TTL (starting from 1) and looking at the ICMP responses. This however could mislead You if some sort of load balancing is being done.
Maybe if You clarified what You would like to achieve I could point You in a better direction.
The RFP for TFTP says that TID's in most circumstances:
should be randomly chosen, so that the probability that the same
number is chosen twice in immediate succession is very low.
The thing is, these "TID"s are also used as UDP port numbers. But a typical network interface cannot just be dedicated for TFTP use. Some ports are liable to be in use, and others should essentially be "reserved" for specific applications. I'm not even sure where a program could go to look up this information at runtime.
So how is a TFTP implementation supposed to deal with this?
Since the host selecting the TID/port is the one opening it and telling the other party which one it's opened, you can simply try to open the port; if it's already in use or otherwise unavailable, this will fail, and you can re-try with a different port. (Note that since UDP and TCP are difference protocols, a TCP application and a UDP application can both be using the "same" port, since they are not, in fact, the same at all!) Do this in a simple loop until you find a "good" one. (Probably best to define a maximum number of tries and simply fail the connection if that's met before a good port is found, as this could be a sign of other issues that prohibit this from working at all.)
Stick to the ephemeral port range to play nice with best practices, although note that different systems define different ranges for this purpose. You could pick the range suitable to your system, or simply try to use a port above the "well-known" port range (i.e. above 1024); this may not give you an "ephemeral port" per se for your system, but so long as you can open it it should work fine.
I have a string that I want to send to another computer that uses my software. I would like to send the string directly to the software in the other computer. Is there any way to do it?
other alternatives are to use tcp or udp broadcasts
If you need to send the string to multiple computers at once you can use a udp broadcast to 255.255.255.255 ; however with udp there is no confirmation of receipt.
Lots of examples are available if you search for them, here is one:
http://msdn.microsoft.com/en-us/library/tst0kwb1(v=VS.71).aspx
A standard way of achieving such task is to use Sockets. There are plenty of examples over the internet depending on the language and environment you are using.
The following link might be useful to you:
http://msdn.microsoft.com/en-us/library/system.net.sockets.socket.aspx
I am working on an app that monitors network usage. However I noticed many ways to do this does not allow exclusion of local traffic (say, Time Machine).
I am looking for a way to exclude local traffic, and only monitors usage that goes directly to/from the internet.
Update: Thank you for your replies, now I know how to find if the traffic is local, but I still don't know how I can calculate total in/out bytes (sorry if I didn't elaborate earlier). I have no way of knowing how many bytes are sent/received locally (or to the internet) in a certain period of time, or since the OS starts. This problem is further complicated by the fact processes are launched or killed when the OS is running.
The answer to the question How to get network adapter stats in linux/Mac OSX? gives an interesting way of summing up total usage but it doesn't help because the usage it sums up are interface statistics.
Update 2: I've posted my final solution to this. Please scroll down a bit to see.
you need to read the source for ifconfig(8), which describes how to get the status of every attached network interface.
pay particular attention to in_status(), which gets the inet address and netmask of an interface.
when the source or destination address in the traffic has the same host as a local interface
int is_local =
(src && netmask) == (ifaddr && netmask)
|| (dst && netmask) == (ifaddr && netmask)
then you can be sure that it is local
http://www.opensource.apple.com/source/network_cmds/network_cmds-307/ifconfig.tproj/ifconfig.c
Answering you comment about which interfaces carry local traffic is actually complicated, because it depends on what you mean by local traffic.
What “Local” Means
The easiest meaning of "local traffic" is traffic that does not leave the machine its generated on (two programs on the same machine talking to each other, for example). This traffic all goes over lo. This is one thing that people mean when they say local (and what I was thinking of when I answered).
The next easiest meaning would be "IP traffic destined to machines on the same subnet". That'd be traffic that has a destination address inside the local subnet. The easiest way to count this is going to be either the routing table (if Mac OS X counts traffic stats per route, the routes on the various gateways will give you non-local traffic) or with a firewall rule. This probably isn't want anyone means when they say "local traffic".
Another meaning would be "IP traffic destined to machines in this (physical) location". E.g., at my office we have several subnets in use, with routers between them, but traffic from one subnet to the other is still clearly local. You need network knowledge to distinguish local from non-local traffic with this definition.
Another meaning would be "IP traffic destined to machines in my organization". This is a reasonable meaning depending on how your network is set up (e.g., maybe you have fast fiber between your locations, but your Internet connections are much slower, or charged per-GB). Requires in-depth knowledge of the network to figure if a destination is going to be local or not—and, with things like VPNs, that may vary over time.
Finally, "Internet traffic" isn't the opposite of any of those. Sometimes, for example, what appears to be a local machine on your Ethernet segment is actually over a VPN, over the Internet (this isn't crazy, it's very useful for when remote users need to use various Windows services). Traffic inside your organization can easily travel over an Internet VPN.
Cheating in Simple Networks
If the network is very simple, with there being only one internal subnet, only one router, and all traffic not to that internal subnet being Internet traffic, you can cheat and solve this. This probably applies to the vast majority of home networks, and many small business ones as well.
Using firewall rules
In a simple network setup, you can probably make some assumptions, and get a close enough answer by counting traffic as non-local if:
the destination MAC address is the default gateway's MAC address; and
the destination IP address is not the default gateway's IP address
alternatively:
the destination IP address is not within the subnet of the network interface the default route goes out
You can probably create a firewall rule to count either of those. At least with Linux iptables you can, and I'm pretty sure BSD pf, and probably Mac OS X.
Alternate Approach: SNMP
Finally, if you can't use a firewall rule (as that'd require root), you could hope that the default gateway responds to SNMP community public, explore all its interfaces, and find the one with a off-subnet IP address, and then assume that is the Internet link. Then you can ask the router for traffic counts on that interface.
Of course, you'll find that many SOHO routers don't support SNMP, and those that do probably don't have it turned on.
The best way is to find the 'external' ip address through the eth0, eth1, or whatever adapter with a system call to ifconfig. Then pull logs for whatever system (messages, syslog, whatever) and write a filter for that external ip address. To make it nicer and more portable, write a regex that will filter for publicly routable IPs only and just filter messages log for that 'external' ip address.
I think, an approximate solution: getifaddrs can be used to get statistics on network usage.
It can get separate statistics for Wi-Fi and WWAN interfaces.
You might find more information from :
http://www.gsp.com/cgi-bin/man.cgi?section=3&topic=getifaddrs
It depends on how you define "local", but a common definition would be to look at the network mask.
For example, if your IP (ie the IP of the interface you monitor is
10.33.52.123
netmask 255.255.255.0
that would mean every IP-packet with both source-IP and destination-IP 10.33.52.xx is local.
I don't know cocoa or objective-c, but you can probably use some of these functions helping you extract the network from an IP-address: http://developer.apple.com/library/mac/#documentation/Darwin/Reference/ManPages/man3/inet_network.3.html
Don't know how to implement it in objective-c but the idea is that you get the address of the network you are in (you can figure this out from network class(A,B,C) based from your local ip or from bits in netmask if it's not standard), then just check the outgoing connection's address. If the destination is not in your local network, calculate traffic; if it's in, just do nothing.
There are three ranges of non-routable IP addresses, and they are commonly used as the address ranges for NAT services. Any address that is not in one of the non-routable address ranges is an external address.
Of course if you are not behind a NAT router, the task is harder (and technically all the addresses short of 127.0.0.1 are external at this point).
The non-routable IP ranges are:
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255
The final working solution I have is to use libpcap to achieve this. Of course there are some downsides, which includes it requires elevated privileges and must capture all filtered packets to calculate statistics, but at least it works perfectly well.
Many documentations and tutorials on libpcap is fairly thorough and clear, I suggest every one interested in this solution to look at those with relatively little google-fu effort.
Also it may interest a few that my filter for internet traffic is simply the following -
- (NSString *)_internetFilterStringForInterface:(AKNetworkInterface *)interface
inOrOut:(BOOL)inYesOutNo
{
if (![interface net] || ![interface mask] || IsEmpty([interface addresses]))
{
return nil;
}
NSString *hostType = inYesOutNo ? #"dst" : #"src";
NSString *host = nil;
for (NSString *hostComponent in [interface addresses])
{
if (IsEmpty(hostComponent)) continue;
if (!host)
host = [NSString stringWithFormat:#"(%# host %#", hostType, hostComponent];
else
host = [host stringByAppendingFormat:#" or %# host %#", hostType, hostComponent];
}
host = [host stringByAppendingString:#")"];
NSString *net = [interface netString];
net = [net stringByReplacingOccurrencesOfString:#".0" withString:#""];
NSString *filter = [NSString stringWithFormat:
#"ip and (not %# net %#) and %#",
inYesOutNo ? #"src" : #"dst",
net, host];
return filter;
}
The filter is designed with some of the answers about what counts as 'local traffic', I know it does not encompass some edge cases such as double NAT configurations, etc., but I would like to see suggestions about this.
I know net = [net stringByReplacingOccurrencesOfString:#".0" withString:#""]; is just a quick hack which could easily fail under some peculiar circumstances but hey no one is complaining, at least not yet.