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  • What is the current state of the art in HTML canvas JavaScript libraries and frameworks?

    - by Toby Hede
    I am currently investigating options for working with the canvas in a new HTML 5 application, and was wondering what is the current state of the art in HTML canvas JavaScript libraries and frameworks? In particular, are there frameworks that support the kind of things needed for game development - complex animation, managing scene graphs, handling events and user interactions? Also willing to consider both commercial and open source products.

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  • Can I use Linq-to-xml to persist my object state without having to use/know Xpath & XSD Syntax?

    - by Greg
    Hi, Can I use Linq-to-xml to persist my object state without having to use/know Xpath & XSD Syntax? ie. really looking for simple but flexible way to persist a graph of object data (e.g. have say 2 or 3 classes with associations) - if Linq-to-xml were as simple as saying "persist this graph to XML", and then you could also query it via Linq, or load it into memory again/change/then re-save to the xml file.

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  • Msg 102, Level 15, State 1, Line 1 Incorrect syntax near ' '.

    - by sajad
    i am trying to query from a temp table,and i keep getting the message Msg 102, Level 15, State 1, Line 1 Incorrect syntax near ' '. can somebody tell me wats the problem..is it due to convert.. plz help The query is select compid,2, convert(datetime, '01/01/' + CONVERT(char(4),cal_yr) ,101) ,0,  Update_dt, th1, th2, th3_pc , Update_id, Update_dt,1 from #tmp_CTF

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  • How do you access country/state/province polygons in google maps api?

    - by wmh1108
    I have fairly large map overlay that I am displaying over the google maps data but would still like to see the country/state/province lines through my overlay (so the lines would essentially be on top of my overlay). As I understand, these lines are simply polygons drawn over the maps. Is there any way to access these? If so, how do I get them to show up through my overlay images?

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  • #altnetseattle &ndash; REST Services

    - by GeekAgilistMercenary
    Below are the notes I made in the REST Architecture Session I helped kick off with Andrew. RSS, ATOM, and such needed for better discovery.  i.e. there still is a need for some type of discovery. Difficult is modeling behaviors in a RESTful way.  ??  Invoking some type of state against an object.  For instance in the case of a POST vs. a GET.  The GET is easy, comes back as is, but what about a POST, which often changes some state or something. Challenge is doing multiple workflows with stateful workflows.  How does batch work.  Maybe model the batch as a resource. Frameworks aren’t particularly part of REST, REST is REST.  But point argued that REST is modeled, or part of modeling a state machine of some sort… ? Nothing is 100% reliable w/ REST – comparisons drawn with TCP/IP.  Sufficient probability is made however for the communications, but the idea of a possible failure has to be built into the usage model of REST. Ruby on Rails / RESTfully, and others used.  What were their issues, what do they do.  ATOM feeds, object serialized, using LINQ to XML w/ this.  No state machine libraries. Idempotent areas around REST and single change POST changes are inherent in the architecture. REST – one of the constrained languages is for the interaction w/ the system.  Limiting what can be done on the resources.  - disagreement, there is no agreed upon REST verbs. Sam Ruby – RESTful services.  Expanded the verbs within REST/HTTP pushes you off the web.  Of the existing verbs POST leaves the most up for debate. Robert Reem used Factory to deal with the POST to handle the new state.  The POST identifying what it just did by the return. Different states are put into POST, so that new prospective verbs, without creating verbs for REST/HTTP can be used to advantage without breaking universal clients. Biggest issue with REST services is their lack of state, yet it is also one of their biggest strengths.  What happens is that the client takes up the often onerous task of handling all state, state machines, and other extraneous resource management.  All the GETs, POSTs, DELETEs, INSERTs get all pushed into abstraction.  My 2 cents is that this in a way ends up pushing a huge proprietary burden onto the REST services often removing the point of REST to be simple and to the point. WADL does provide discovery and some state control (sort of?) Statement made, "WADL" isn't needed.  The JSON, XML, or other client side returned data handles this. I then applied the law of 2 feet rule for myself and headed to finish up these notes, post to the Wiki, and figure out what I was going to do next.  For the original Wiki entry check it out here. I will be adding more to this post with a subsequent post.  Please do feel free to post your thoughts and ideas about this, as I am sure everyone in the session will have more for elaboration.

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  • WiX, MSDeploy and an appealing configuration/deployment paradigm

    - by alexhildyard
    I do a lot of application and server configuration; I've done this for many years and have tended to view the complexity of this strictly in terms of the complexity of the ultimate configuration to be deployed. For example, specific APIs aside, I would tend to regard installing a server certificate as a more complex activity than, say, copying a file or adding a Registry entry.My prejudice revolved around the idea of a sequential deployment script that not only had the explicit prescription to apply a specific server configuration, but also made the implicit presumption that the server in question was in a good known state. Scripts like this fail for hundreds of reasons -- the Default Website didn't exist; the application had already been deployed; the application had already been partially deployed and failed to rollback fully, and so on. And so the problem is that the more complex the configuration activity, the more scope for error in any individual part of that activity, and therefore the greater the chance the server in question will not end up at exactly the desired configuration level.Recently I was introduced to a completely different mindset, which, for want of a better turn of phrase, I will call the "make it so" mindset. It's extremely simple both to explain and to implement. In place of the head-down, imperative script you used to use, you substitute a set of checks -- much like exception handlers -- around each configuration activity, starting with a check of the current system state. Thus the configuration logic becomes: "IF these services aren't started then start them, and IF XYZ website doesn't exist then create it, and IF these shares don't exist then create them, and IF these shares aren't permissioned in some particular way, then permission them so." This works. Really well, in my experience. Scenario 1: You want to get a system into a good known state; it's already in a good known state; you quickly realise there is nothing to do.Scenario 2: You want to get the system into a good known state; your script is flawed or the system is bust; it cannot be put into that state. You know exactly where (at least part of) the problem is and why.Scenario 3: You want to get the system into a good known state; people are fiddling around with the system just now. That's fine. You do what you can, and later you come back and try it againScenario 4: No one wants to deploy anything; they want you to prove that the previous deployment was successful. So you re-run the deployment script with the "-WhatIf" flag. It reports that there was nothing to change. There's your proof.I mentioned two technologies in the title -- MSI and MSDeploy. I am thinking specifically of the conversation that took place here. Having worked with both technologies, I think Rob Mensching's response is appropriately nuanced, and in essence the difference is this: sometimes your target is either to achieve a specific new server state, or to rollback to a known good one. Then again, your target may be to configure what you can, and to understand what you can't. Implicitly MSDeploy's "rollback" is simply to redeploy the previous version, whereas a well-crafted MSI will actively put your system into that state without further intervention. Either way, if all goes well it will leave you with a system in one of two states, whereas MSDeploy could leave your system in one of many states. The key is that MSDeploy and MSI are complementary technologies; which suits you best depends as much on Operational guidance as your Configuration remit.What I wanted to say was that I have always been for atomic, transactional-based configuration, but having worked with the "make it so" paradigm, I have been favourably impressed by the actual results. I'm tempted to put a more technical post up on this in due course.

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  • Flushing iptables broke my pipe, how can I save my instance?

    - by Niels
    I was setting up my iptables when I performed a iptables -F and my ssh pipe broke. This is the last output of my session: root@alfapaints:~# iptables -L Chain INPUT (policy DROP) target prot opt source destination ACCEPT all -- anywhere anywhere ACCEPT tcp -- anywhere anywhere state NEW,ESTABLISHED tcp dpt:2222 ACCEPT tcp -- li465-68.members.linode.com anywhere state NEW,ESTABLISHED tcp dpt:nrpe ACCEPT tcp -- anywhere anywhere tcp dpt:9200 state NEW,ESTABLISHED ACCEPT tcp -- anywhere anywhere tcp dpt:http state NEW,ESTABLISHED ACCEPT udp -- anywhere anywhere udp spt:domain Chain FORWARD (policy DROP) target prot opt source destination Chain OUTPUT (policy DROP) target prot opt source destination ACCEPT all -- anywhere anywhere ACCEPT tcp -- anywhere anywhere state ESTABLISHED tcp spt:2222 ACCEPT tcp -- anywhere anywhere state ESTABLISHED tcp spt:nrpe ACCEPT tcp -- anywhere anywhere tcp spt:9200 state ESTABLISHED ACCEPT tcp -- anywhere anywhere tcp spt:http state ESTABLISHED ACCEPT udp -- anywhere anywhere udp dpt:domain root@alfapaints:~# iptables -F Write failed: Broken pipe I tested my connection just before and I was able to connect with ssh. Now I did a nmap scan and not a single port is open anymore. I know my VPS is running on VMWare ESXi, could a reboot help? Or if not could I attach and mount the disk to another vm to save the data? Does anybody have some advise? And maybe an explanation what happend or what could have cause my pipe to break? ps: I didn't save my rules on the config directories of iptables. But used a file I stored in ~/rules.config to apply my rules like this: iptables-restore < rules.config So probably a reboot would help? Thanks a lot in advance.

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  • Bypassing SQUID on freebsd with PF

    - by epema
    I have PF+SQUID31 on FREEBSD-9.0, and I want to have some hosts(aka goodguys) to bypass the proxy, so that torrents are not logged. Also, I am not sure about transparent. It means that I dont have to configure proxy settings on the client side right? I have tried doing a redirect no rdr on $int_if inet proto {tcp,udp} from 192.168.1.233/32 to any However, no luck :( Here is a quick look of my conf files: SQUID /usr/local/etc/squid/squid.conf http_port 192.168.1.1:8080 transparent RC /etc/rc.conf: gateway_enable="YES" pf_enable="YES" pf_rules="/usr/local/etc/pf.conf" pflog_enable="YES" squid_enable="YES" I have squid31 installed from ports with SQUID_PF "Enable transparent proxying with PF" on PF /usr/loca/etc/pf.conf: int_if="re0" ext_if="bge0" localnet="{ 192.168.1.0/24 }" table <goodguys> const { "192.168.1.219", "192.168.1.233" } set block-policy drop set skip on lo0 scrub in all fragment reassemble scrub out all random-id max-mss 1440 block in on $ext_if pass out on $ext_if keep state block in on $int_if pass in on $int_if inet proto tcp from $int_if:network to $int_if port 8080 keep state pass in on $int_if inet proto udp from $int_if:network to $int_if port 21 keep state pass in on $int_if inet proto udp from $int_if:network to $int_if port 22 keep state pass in on $int_if inet proto udp from $int_if:network to $int_if port 53 keep state pass in on $int_if inet proto tcp from $int_if:network to any port { smtp, pop3 } keep state pass in on $int_if inet proto icmp from $int_if:network to $int_if keep state pass out on $int_if keep state What lines should I add in conf files? I am assuming that the problem is on the firewall(pf).

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  • How to access a port via OpenVpn only

    - by Andy M
    I've set up an openvpn server alongside an apache website that can only be accessed on port 8100 on the same machine. My /etc/openvpn/server.conf file looks like this: port 1194 proto tcp dev tun ca ./easy-rsa2/keys/ca.crt cert ./easy-rsa2/keys/server.crt key ./easy-rsa2/keys/server.key # This file should be kept secret dh ./easy-rsa2/keys/dh1024.pem # Diffie-Hellman parameter server 10.8.0.0 255.255.255.0 ifconfig-pool-persist ipp.txt # make sure clients can still connect to the internet push "redirect-gateway def1 bypass-dhcp" keepalive 10 120 comp-lzo persist-key persist-tun status openvpn-status.log verb 3 Now I tried to let only clients connected to the vpn network access the website on apache via port 8100. So I defined a few iptables rules: #!/bin/sh # My system IP/set ip address of server SERVER_IP="192.168.0.2" # Flushing all rules iptables -F iptables -X # Setting default filter policy iptables -P INPUT DROP iptables -P OUTPUT DROP iptables -P FORWARD DROP # Allow incoming access to port 8100 from OpenVPN 10.8.0.1 iptables -A INPUT -i tun0 -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -o tun0 -p tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT # outgoing http iptables -A OUTPUT -o tun0 -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT iptables -A INPUT -i tun0 -p tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT Now when I connect to the server from my client computer and try to access the website on 192.168.0.2:8100, my browser can't open it. Will I have to forward traffic from tun0 to eth0? Or is there anything else I'm missing?

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  • How long will a "safely stored" Solid-State-Drive (SSD) keep its data? (e.g. bank safety-deposit box)

    - by user31575
    Here's my usecase: once-and-only-once copy off photos/videos to an internal SATA Solid State Drive (SSD) put this drive in a well-ventilated, air-conditioned bank "safety deposit box" for safe keeping The question: How long can I safely store a solid-state-drive in such an environment? i.e. 0% bitrot, 100% success when "plugged in" Are some SSD drives more reliable than other for this usecase? (e.g. smaller size vs larger size, SLC vs MLC, different brands, etc) More fodder: I have read that solid state memory cards (e..g compactflash, or sd cards) have much longer durability than other media (DVD's, CD's, hard drives) for this usecase (guaranteed against bitrot/other dysfunction on the order of ~ a decades vs a year ). I don't know if this applies to "SSD hard drives". Copying to one 500Gb ssd vs 8 64gb flash drives is easier SSD SATA hard drives have no moving parts, but they have more "visible electronics" than a compact flash card. I don't know if this "visible electronics" can fail, i.e. in contr I know many will point to carbonite, other cloud backup stuff, but I like the simplicity of having physical copies and wanted to understand the risks/implications thanks,

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  • NumLock is so weired in Ubuntu

    - by ???
    The NumLock and the keypad is so weired in Ubuntu. I have two computers, A is a desktop, with USB keyboard, B is a laptop, with laptop keyboard and another USB keyboard. On the desktop A, whether the NumLock is on or off, the number keys on the keypad just don't work. Also the NumLock LED is always off. The logs shown in xev: KeyPress event, serial 36, synthetic NO, window 0x6800001, root 0xb0, subw 0x0, time 9541332, (172,-12), root:(1846,452), state 0x0, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False KeyRelease event, serial 36, synthetic NO, window 0x6800001, root 0xb0, subw 0x0, time 9541412, (172,-12), root:(1846,452), state 0x0, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False And on the laptop B, I found that, when the NumLock is on, then many key combinations won't work. For example, generally Ctrl-A is used to select all, but it won't work when NumLock is on. The logs shown in xev: (no log when pressed Fn+NumLock on the laptop keyboard) Logs when pressed the NumLock on the USB keyboard: (Switch On) KeyPress event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22187595, (102,107), root:(1198,133), state 0x10, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False PropertyNotify event, serial 40, synthetic NO, window 0xb600001, atom 0x1b8 (XKLAVIER_STATE), time 22187601, state PropertyNewValue KeyRelease event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22187723, (102,107), root:(1198,133), state 0x10, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False (Switch Off) KeyPress event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22187899, (102,107), root:(1198,133), state 0x0, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False PropertyNotify event, serial 40, synthetic NO, window 0xb600001, atom 0x1b8 (XKLAVIER_STATE), time 22187904, state PropertyNewValue KeyRelease event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22188003, (102,107), root:(1198,133), state 0x10, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False

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  • How to set a static route for an external IP address

    - by HorusKol
    Further to my earlier question about bridging different subnets - I now need to route requests for one particular IP address differently to all other traffic. I have the following routing in my iptables on our router: # Allow established connections, and those !not! coming from the public interface # eth0 = public interface # eth1 = private interface #1 (10.1.1.0/24) # eth2 = private interface #2 (129.2.2.0/25) iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT iptables -A INPUT -m state --state NEW ! -i eth0 -j ACCEPT iptables -A FORWARD -i eth0 -o eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT iptables -A FORWARD -i eth0 -o eth2 -m state --state ESTABLISHED,RELATED -j ACCEPT # Allow outgoing connections from the private interfaces iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT iptables -A FORWARD -i eth2 -o eth0 -j ACCEPT # Allow the two private connections to talk to each other iptables -A FORWARD -i eth1 -o eth2 -j ACCEPT iptables -A FORWARD -i eth2 -o eth1 -j ACCEPT # Masquerade (NAT) iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE # Don't forward any other traffic from the public to the private iptables -A FORWARD -i eth0 -o eth1 -j REJECT iptables -A FORWARD -i eth0 -o eth2 -j REJECT This configuration means that users will be forwarded through a modem/router with a public address - this is all well and good for most purposes, and in the main it doesn't matter that all computers are hidden behind the one public IP. However, some users need to be able to access a proxy at 192.111.222.111:8080 - and the proxy needs to identify this traffic as coming through a gateway at 129.2.2.126 - it won't respond otherwise. I tried adding a static route on our local gateway with: route add -host 192.111.222.111 gw 129.2.2.126 dev eth2 I can successfully ping 192.111.222.111 from the router. When I trace the route, it lists the 129.2.2.126 gateway, but I just get * on each of the following hops (I think this makes sense since this is just a web-proxy and requires authentication). When I try to ping this address from a host on the 129.2.2.0/25 network it fails. Should I do this in the iptables chain instead? How would I configure this routing?

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  • How to make NumLock behavior just like in Windows?

    - by ???
    The NumLock and the keypad is so weired in Ubuntu. I have two computers, A is a desktop, with USB keyboard, B is a laptop, with laptop keyboard and another USB keyboard. On the desktop A, whether the NumLock is on or off, the number keys on the keypad just don't work. Also the NumLock LED is always off. The logs shown in xev: KeyPress event, serial 36, synthetic NO, window 0x6800001, root 0xb0, subw 0x0, time 9541332, (172,-12), root:(1846,452), state 0x0, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False KeyRelease event, serial 36, synthetic NO, window 0x6800001, root 0xb0, subw 0x0, time 9541412, (172,-12), root:(1846,452), state 0x0, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False And on the laptop B, I found that, when the NumLock is on, then many key combinations won't work. For example, generally Ctrl-A is used to select all, but it won't work when NumLock is on. The logs shown in xev: (no log when pressed Fn+NumLock on the laptop keyboard) Logs when pressed the NumLock on the USB keyboard: (Switch On) KeyPress event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22187595, (102,107), root:(1198,133), state 0x10, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False PropertyNotify event, serial 40, synthetic NO, window 0xb600001, atom 0x1b8 (XKLAVIER_STATE), time 22187601, state PropertyNewValue KeyRelease event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22187723, (102,107), root:(1198,133), state 0x10, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False (Switch Off) KeyPress event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22187899, (102,107), root:(1198,133), state 0x0, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False PropertyNotify event, serial 40, synthetic NO, window 0xb600001, atom 0x1b8 (XKLAVIER_STATE), time 22187904, state PropertyNewValue KeyRelease event, serial 40, synthetic NO, window 0xb600001, root 0xac, subw 0x0, time 22188003, (102,107), root:(1198,133), state 0x10, keycode 77 (keysym 0xff7f, Num_Lock), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False

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  • Problems creating a functioning table

    - by Hoser
    This is a pretty simple SQL query I would assume, but I'm having problems getting it to work. if (object_id('#InfoTable')is not null) Begin Drop Table #InfoTable End create table #InfoTable (NameOfObject varchar(50), NameOfCounter varchar(50), SampledValue float(30), DayStamp datetime) insert into #InfoTable(NameOfObject, NameOfCounter, SampledValue, DayStamp) select vPerformanceRule.ObjectName AS NameOfObject, vPerformanceRule.CounterName AS NameOfCounter, Perf.vPerfRaw.SampleValue AS SampledValue, Perf.vPerfHourly.DateTime AS DayStamp from vPerformanceRule, vPerformanceRuleInstance, Perf.vPerfHourly, Perf.vPerfRaw where (ObjectName like 'Logical Disk' and CounterName like '% Free Space' AND SampleValue > 95 AND SampleValue < 100) order by DayStamp desc select NameOfObject, NameOfCounter, SampledValue, DayStamp from #InfoTable Drop Table #InfoTable I've tried various other forms of syntax, but no matter what I do, I get these error messages. Msg 207, Level 16, State 1, Line 10 Invalid column name 'NameOfObject'. Msg 207, Level 16, State 1, Line 10 Invalid column name 'NameOfCounter'. Msg 207, Level 16, State 1, Line 10 Invalid column name 'SampledValue'. Msg 207, Level 16, State 1, Line 10 Invalid column name 'DayStamp'. Msg 207, Level 16, State 1, Line 22 Invalid column name 'NameOfObject'. Msg 207, Level 16, State 1, Line 22 Invalid column name 'NameOfCounter'. Msg 207, Level 16, State 1, Line 22 Invalid column name 'SampledValue'. Msg 207, Level 16, State 1, Line 22 Invalid column name 'DayStamp'. Line 10 is the first 'insert into' line, and line 22 is the second select line. Any ideas?

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  • SNMP query - operation not permitted

    - by jperovic
    I am working on API that reads a lot of data via SNMP (routes, interfaces, QoS policies, etc...). Lately, I have experienced a random error stating: Operation not permitted Now, I use SNMP4J as core library and cannot really pinpoint the source of error. Some Stackoverflow questions have suggested OS being unable to open sufficient number of file handles but increasing that parameter did not help much. The strange thing is that error occurs only when iptables is up and running. Could it be that firewall is blocking some traffic? I have tried writing JUnit test that mimicked application's logic but no errors were fired... Any help would be appreciated! Thanks! IPTABLES *nat :PREROUTING ACCEPT [2:96] :POSTROUTING ACCEPT [68:4218] :OUTPUT ACCEPT [68:4218] # route redirect za SNMP Trap i syslog -A PREROUTING -i eth0 -p udp -m udp --dport 514 -j REDIRECT --to-ports 33514 -A PREROUTING -i eth0 -p udp -m udp --dport 162 -j REDIRECT --to-ports 33162 COMMIT *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT -A INPUT -p icmp -j ACCEPT -A INPUT -i lo -j ACCEPT ..... # SNMP -A INPUT -p udp -m state --state NEW -m udp --dport 161 -j ACCEPT # SNMP trap -A INPUT -p udp -m state --state NEW -m udp --dport 162 -j ACCEPT -A INPUT -p udp -m state --state NEW -m udp --dport 33162 -j ACCEPT ..... -A INPUT -j REJECT --reject-with icmp-host-prohibited -A FORWARD -j REJECT --reject-with icmp-host-prohibited COMMIT

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  • Linux - Only first virtual interface can ping external gateway

    - by husvar
    I created 3 virtual interfaces with different mac addresses all linked to the same physical interface. I see that they successfully arp for the gw and they can ping (the request is coming in the packet capture in wireshark). However the ping utility does not count the responses. Does anyone knows the issue? I am running Ubuntu 14.04 in a VmWare. root@ubuntu:~# ip link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff inet6 fe80::20c:29ff:febc:fc8b/64 scope link valid_lft forever preferred_lft forever root@ubuntu:~# ip route sh root@ubuntu:~# ip link add link eth0 eth0.1 addr 00:00:00:00:00:11 type macvlan root@ubuntu:~# ip link add link eth0 eth0.2 addr 00:00:00:00:00:22 type macvlan root@ubuntu:~# ip link add link eth0 eth0.3 addr 00:00:00:00:00:33 type macvlan root@ubuntu:~# ip -4 link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff 18: eth0.1@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:11 brd ff:ff:ff:ff:ff:ff 19: eth0.2@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:22 brd ff:ff:ff:ff:ff:ff 20: eth0.3@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:33 brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip -4 addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever root@ubuntu:~# ip -4 route sh root@ubuntu:~# dhclient -v eth0.1 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.1/00:00:00:00:00:11 Sending on LPF/eth0.1/00:00:00:00:00:11 Sending on Socket/fallback DHCPDISCOVER on eth0.1 to 255.255.255.255 port 67 interval 3 (xid=0x568eac05) DHCPREQUEST of 192.168.1.145 on eth0.1 to 255.255.255.255 port 67 (xid=0x568eac05) DHCPOFFER of 192.168.1.145 from 192.168.1.254 DHCPACK of 192.168.1.145 from 192.168.1.254 bound to 192.168.1.145 -- renewal in 1473 seconds. root@ubuntu:~# dhclient -v eth0.2 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.2/00:00:00:00:00:22 Sending on LPF/eth0.2/00:00:00:00:00:22 Sending on Socket/fallback DHCPDISCOVER on eth0.2 to 255.255.255.255 port 67 interval 3 (xid=0x21e3114e) DHCPREQUEST of 192.168.1.146 on eth0.2 to 255.255.255.255 port 67 (xid=0x21e3114e) DHCPOFFER of 192.168.1.146 from 192.168.1.254 DHCPACK of 192.168.1.146 from 192.168.1.254 bound to 192.168.1.146 -- renewal in 1366 seconds. root@ubuntu:~# dhclient -v eth0.3 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.3/00:00:00:00:00:33 Sending on LPF/eth0.3/00:00:00:00:00:33 Sending on Socket/fallback DHCPDISCOVER on eth0.3 to 255.255.255.255 port 67 interval 3 (xid=0x11dc5f03) DHCPREQUEST of 192.168.1.147 on eth0.3 to 255.255.255.255 port 67 (xid=0x11dc5f03) DHCPOFFER of 192.168.1.147 from 192.168.1.254 DHCPACK of 192.168.1.147 from 192.168.1.254 bound to 192.168.1.147 -- renewal in 1657 seconds. root@ubuntu:~# ip -4 link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff 18: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:11 brd ff:ff:ff:ff:ff:ff 19: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:22 brd ff:ff:ff:ff:ff:ff 20: eth0.3@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:33 brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip -4 addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever 18: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.145/24 brd 192.168.1.255 scope global eth0.1 valid_lft forever preferred_lft forever 19: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.146/24 brd 192.168.1.255 scope global eth0.2 valid_lft forever preferred_lft forever 20: eth0.3@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.147/24 brd 192.168.1.255 scope global eth0.3 valid_lft forever preferred_lft forever root@ubuntu:~# ip -4 route sh default via 192.168.1.254 dev eth0.1 192.168.1.0/24 dev eth0.1 proto kernel scope link src 192.168.1.145 192.168.1.0/24 dev eth0.2 proto kernel scope link src 192.168.1.146 192.168.1.0/24 dev eth0.3 proto kernel scope link src 192.168.1.147 root@ubuntu:~# arping -c 5 -I eth0.1 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.145 eth0.1 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 6.936ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.986ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 0.654ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 5.137ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.426ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# arping -c 5 -I eth0.2 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.146 eth0.2 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 5.665ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 3.753ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 16.500ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 3.287ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 32.438ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# arping -c 5 -I eth0.3 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.147 eth0.3 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 4.422ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.429ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.321ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 40.423ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.268ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# tcpdump -n -i eth0.1 -v & [1] 5317 root@ubuntu:~# ping -c5 -q -I eth0.1 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.145 eth0.1: 56(84) bytes of data. tcpdump: listening on eth0.1, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:37.612558 IP (tos 0x0, ttl 64, id 2595, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 2, length 64 13:18:37.618864 IP (tos 0x68, ttl 64, id 14493, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 2, length 64 13:18:37.743650 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:38.134997 IP (tos 0x0, ttl 128, id 23547, offset 0, flags [none], proto UDP (17), length 229) 192.168.1.86.138 > 192.168.1.255.138: NBT UDP PACKET(138) 13:18:38.614580 IP (tos 0x0, ttl 64, id 2596, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 3, length 64 13:18:38.793479 IP (tos 0x68, ttl 64, id 14495, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 3, length 64 13:18:39.151282 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:39.615612 IP (tos 0x0, ttl 64, id 2597, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 4, length 64 13:18:39.746981 IP (tos 0x68, ttl 64, id 14496, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 4, length 64 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4008ms rtt min/avg/max/mdev = 2.793/67.810/178.934/73.108 ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 9 packets captured 12 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.1 -v root@ubuntu:~# tcpdump -n -i eth0.2 -v & [1] 5320 root@ubuntu:~# ping -c5 -q -I eth0.2 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.146 eth0.2: 56(84) bytes of data. tcpdump: listening on eth0.2, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:41.536874 ARP, Ethernet (len 6), IPv4 (len 4), Reply 192.168.1.254 is-at 58:98:35:57:a0:70, length 46 13:18:41.536933 IP (tos 0x0, ttl 64, id 2599, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 1, length 64 13:18:41.539255 IP (tos 0x68, ttl 64, id 14507, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 1, length 64 13:18:42.127715 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:42.511725 IP (tos 0x0, ttl 64, id 2600, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 2, length 64 13:18:42.514385 IP (tos 0x68, ttl 64, id 14527, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 2, length 64 13:18:42.743856 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:43.511727 IP (tos 0x0, ttl 64, id 2601, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 3, length 64 13:18:43.513768 IP (tos 0x68, ttl 64, id 14528, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 3, length 64 13:18:43.637598 IP (tos 0x0, ttl 128, id 23551, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 255.255.255.255.17500: UDP, length 197 13:18:43.641185 IP (tos 0x0, ttl 128, id 23552, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 192.168.1.255.17500: UDP, length 197 13:18:43.641201 IP (tos 0x0, ttl 128, id 23553, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 255.255.255.255.17500: UDP, length 197 13:18:43.743890 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:44.510758 IP (tos 0x0, ttl 64, id 2602, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 4, length 64 13:18:44.512892 IP (tos 0x68, ttl 64, id 14538, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 4, length 64 13:18:45.510794 IP (tos 0x0, ttl 64, id 2603, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 5, length 64 13:18:45.519701 IP (tos 0x68, ttl 64, id 14539, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 5, length 64 13:18:49.287554 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:50.013463 IP (tos 0x0, ttl 255, id 50737, offset 0, flags [DF], proto UDP (17), length 73) 192.168.1.146.5353 > 224.0.0.251.5353: 0 [2q] PTR (QM)? _ipps._tcp.local. PTR (QM)? _ipp._tcp.local. (45) 13:18:50.218874 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:51.129961 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:52.197074 IP6 (hlim 255, next-header UDP (17) payload length: 53) 2001:818:d812:da00:200:ff:fe00:22.5353 > ff02::fb.5353: [udp sum ok] 0 [2q] PTR (QM)? _ipps._tcp.local. PTR (QM)? _ipp._tcp.local. (45) 13:18:54.128240 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 0 received, 100% packet loss, time 4000ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 13:18:54.657731 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:54.743174 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 25 packets captured 26 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.2 -v root@ubuntu:~# tcpdump -n -i eth0.3 icmp & [1] 5324 root@ubuntu:~# ping -c5 -q -I eth0.3 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.147 eth0.3: 56(84) bytes of data. tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0.3, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:56.373434 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 1, length 64 13:18:57.372116 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 2, length 64 13:18:57.381263 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 2, length 64 13:18:58.371141 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 3, length 64 13:18:58.373275 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 3, length 64 13:18:59.371165 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 4, length 64 13:18:59.373259 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 4, length 64 13:19:00.371211 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 5, length 64 13:19:00.373278 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 5, length 64 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 1 received, 80% packet loss, time 4001ms rtt min/avg/max/mdev = 13.666/13.666/13.666/0.000 ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 9 packets captured 10 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.3 icmp root@ubuntu:~# arp -n Address HWtype HWaddress Flags Mask Iface 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.1 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.2 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.3

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  • Generics with constraints hierarchy

    - by devoured elysium
    I am currently facing a very disturbing problem: interface IStateSpace<Position, Value> where Position : IPosition // <-- Problem starts here where Value : IValue // <-- and here as I don't { // know how to get away this // circular dependency! // Notice how I should be // defining generics parameters // here but I can't! Value GetStateAt(Position position); void SetStateAt(Position position, State state); } As you'll down here, both IPosition, IValue and IState depend on each other. How am I supposed to get away with this? I can't think of any other design that will circumvent this circular dependency and still describes exactly what I want to do! interface IState<StateSpace, Value> where StateSpace : IStateSpace where Value : IValue { StateSpace StateSpace { get; }; Value Value { get; set; } } interface IPosition { } interface IValue<State> where State : IState { State State { get; } } Basically I have a state space IStateSpace that has states IState inside. Their position in the state space is given by an IPosition. Each state then has one (or more) values IValue. I am simplifying the hierarchy, as it's a bit more complex than described. The idea of having this hierarchy defined with generics is to allow for different implementations of the same concepts (an IStateSpace will be implemented both as a matrix as an graph, etc). Would can I get away with this? How do you generally solve this kind of problems? Which kind of designs are used in these cases? Thanks

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  • verilog / systemverilog -- What is the behavior of blocking statements across two always blocks?

    - by miles.sherman
    I am wondering about the behavior of the below code. There are two always blocks, one is combinational to calculate the next_state signal, the other is sequential which will perform some logic and determine whether or not to shutdown the system. It does this by setting the shutdown_now signal high and then calling state <= next_state. My question is if the conditions become true that the shutdown_now signal is set (during clock cycle n) in a blocking manner before the state <= next_state line, will the state during clock cycle n+1 be SHUTDOWN or RUNNING? In other words, does the shutdown_now = 1'b1 line block across both state machines since the state signal is dependent on it through the next_state determination? enum {IDLE, RUNNING, SHUTDOWN} state, next_state; logic shutdown_now; // State machine (combinational) always_comb begin case (state) IDLE: next_state <= RUNNING; RUNNING: next_state <= shutdown ? SHUTDOWN : RUNNING; SHUTDOWN: next_state <= SHUTDOWN; default: next_state <= SHUTDOWN; endcase end // Sequential Behavior always_ff @ (posedge clk) begin // Some code here if (/*some condition) begin shutdown_now = 1'b0; end else begin shutdown_now = 1'b1; end state <= next_state; end

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  • How can I SETF an element in a tree by an accessor?

    - by Willi Ballenthin
    We've been using Lisp in my AI course. The assignments I've received have involved searching and generating tree-like structures. For each assignment, I've ended up writing something like: (defun initial-state () (list 0 ; score nil ; children 0 ; value 0)) ; something else and building my functions around these "states", which are really just nested lists with some loosely defined structure. To make the structure more rigid, I've tried to write accessors, such as: (defun state-score ( state ) (nth 2 state)) This works for reading the value (which should be all I need to do in a nicely functional world. However, as time crunches, and I start to madly hack, sometimes I want a mutable structure). I don't seem to be able to SETF the returned ...thing (place? value? pointer?). I get an error with something like: (setf (state-score *state*) 10) Sometimes I seem to have a little more luck writing the accessor/mutator as a macro: (defmacro state-score ( state ) `(nth 2 ,state)) However I don't know why this should be a macro, so I certainly shouldn't write it as a macro (except that sometimes it works. Programming by coincidence is bad). What is an appropriate strategy to build up such structures? More importantly, where can I learn about whats going on here (what operations affect the memory in what way)?

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  • Dynamic select menu Rails, Javascript HABTM

    - by Jack
    Hi, I am following a tutorial in one of Ryan Bates' Railscasts here. Basically I want a form where there are 2 drop down menus, the contents of one are dependent on the other. I have Years and Courses, where Years HABMT Courses and Courses HABTM Years. In the tutorial, the javascript is as follows: var states = new Array(); <% for state in @states -%> states.push(new Array(<%= state.country_id %>, '<%=h state.name %>', <%= state.id %>)); <% end -%> function countrySelected() { country_id = $('person_country_id').getValue(); options = $('person_state_id').options; options.length = 1; states.each(function(state) { if (state[0] == country_id) { options[options.length] = new Option(state[1], state[2]); } }); if (options.length == 1) { $('state_field').hide(); } else { $('state_field').show(); } } document.observe('dom:loaded', function() { countrySelected(); $('person_country_id').observe('change', countrySelected); }); Where I guess country has many states and state belongs to country. I think what I need to do is edit the first for statement to somehow loop through all of the courses for each year_id, but don't know how to do this. Any ideas? Thanks

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