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  • Providing DNS redirection to honeypot server for known bad domains

    - by syn-
    Currently running BIND on RHEL 5.4 and am looking for a more efficient manner of providing DNS redirection to a honeypot server for a large (30,000+) list of forbidden domains. Our current solution for this requirement is to include a file containing a zone master declaration for each blocked domain in named.conf. Subsequently, each of these zone declarations point to the same zone file, which resolves all hosts in that domain to our honeypot servers. ...basically this allows us to capture any "phone home" attempts by malware that may infiltrate the internal systems. The problem with this configuration is the large amount of time taken to load all 30,000+ domains as well as management of the domain list configuration file itself... if any errors creep into this file, the BIND server will fail to start, thereby making automation of the process a little frightening. So I'm looking for something more efficient and potentially less error prone. named.conf entry: include "blackholes.conf"; blackholes.conf entry example: zone "bad-domain.com" IN { type master; file "/var/named/blackhole.zone"; allow-query { any; }; notify no; }; blackhole.zone entries: $INCLUDE std.soa @ NS ns1.ourdomain.com. @ NS ns2.ourdomain.com. @ NS ns3.ourdomain.com.                        IN            A                192.168.0.99 *                      IN            A                192.168.0.99

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  • TCP failure on Solaris

    - by anurag kohli
    Hi All, I recently ran into a problem where a Solaris server could not establish a TCP socket on port 2126. From a packet capture I see this (note: A is a Solaris server, B is a router): A sends SYN to B B sends SYN, ACK to A Notice A (Solaris) does not acknowledge the SYN from B. Due to the business impact of the problem, I had to reboot the server to fix the problem. That said, I want to know the next time the problem occurs, what can I do to get a root cause (ie before server reboot)? Thanks in advance.

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  • How is the MTU is 65535 in UDP but ethernet does not allow frame size more than 1500 bytes

    - by nikku
    I am using a fast ethernet of 100 Mbps, whose frame size is less than 1500 bytes (1472 bytes for payload as per my textbook). In that, I was able to send and receive a UDP packet of message size 65507 bytes, which means the packet size was 65507 + 20 (IP Header) + 8 (UDP Header) = 65535. If the frame's payload size itself is maximum of 1472 bytes (as per my textbook), how can the packet size of IP be greater than that which here is 65535? I used sender code as char buffer[100000]; for (int i = 1; i < 100000; i++) { int len = send (socket_id, buffer, i); printf("%d\n", len); } Receiver code as while (len = recv (socket_id, buffer, 100000)) { printf("%d\n". len); } I observed that send returns -1 on i > 65507 and recv prints or receives a packet of maximum of length 65507.

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  • Load balancing + NAT issue on BNT GBE 2-7 gear

    - by Clément Game
    Hi guys, I've got troubles configuring an Hardware load-Balancer with NAT functions. I have the following architecture: Internet === VIP (public) LB (private ip) ==== private addressed servers When a connection is initialised from the outside (internet) , the LB correctly forwards the SYN packet to one of the private servers. But when these servers want to reply with a SYN/ACK there is a problem. the initial SYN packet had as ip header : VIP = Private_server_Address But the private servers cannot reach VIP from their side (this is normal since it's nated), and then provide a correct reply. Have you guys any solution to correctly forward the packets to their correct destination ? Note: The load balancer, which is the default gw for the servers, also has a NAT rule for "masquerading" (actually more SNAT than real masquerading) Regards, Clément.

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  • iptables rule on INPUT between 2 ethernet cards on the same host

    - by user1495181
    I have 2 eth cards on the same host. Both connected directly with LAN cable. I set eth0 with ip - 192.168.1.2 I set eth1 with ip - 192.168.1.1 I set this rule: iptables -A INPUT -p tcp -j NFQUEUE --queue-num 0 There are no other rules. (I ran iptables -X,-F) I send TCP syn packet ( with c++ program by using raw socket) from 192.168.1.2 to 192.168.1.1 In wireshark i see that the packet received on eth0, but the iptables rule (above) dosnt apply for this packet. when i sent the packet to remote host and apply this rule on the remote host than it work correct. So, i guess that this is due to the fact that both eth cards exists the same host. . I need to create iptables INPUT rule for local eth card (dest and src on the same machine ). I need it for simplify test. Did i guess the problem correct? is there a way to bypass this? Ps - connected them via switch didn't help. the rule wasn't applied. Run on Ubuntu. TCDUMP show the packet: 10:48:42.365002 IP 192.168.1.2.38550 > 192.168.1.1.34298: Flags [S], seq 0, win 5840, length 0 but logging of iptables like this, has nothing: iptables -A INPUT -p tcp -j LOG --log-prefix '*****************' iptables -A OUTPUT -p tcp -j LOG --log-prefix '#################'

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  • Can a network interface be configured to have a default gateway for UDP packets?

    - by Vaibhav
    It is quite possible that my question may not make a lot of sense. I apologize, but I am not a networking guy, and that's my excuse. To elaborate, WikiPedia defines "Default Gateway" as a node on a "TCP/IP" network. And the way it works is that if a network interface is sending a packet to an IP address not present on its subnet, it sends it out to the default gateway (which then knows what to do with that packet). Is this true if a UDP packet (datagram) is involved? I mean, if my network interface is sending a UDP packet to an IP address that is not present on its subnet, would it automatically send it to the Default Gateway as well?

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  • Is there a config value in Wine to force Enter to send CR+LF?

    - by bedwyr
    I'm pretty new to Wine and I'm trying to use an IM client which is required for my work. When I hit 'Enter' to send a chat message, the characters indicating a new line are not being correctly interpreted. Here's a basic SYN-ACK between the two of us: His view: me: SYN!him: ACK! My view: him: SYN!me: ACK!me: ACK! Is there any way I can configure Wine to handle this correctly? Please note: this is a required application and I have no way to change its configuration.

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  • Using u32 together with extension headers (how to jump over them?)

    - by bortzmeyer
    I'm trying to filter on some parts of the payload, for an IPv6 packet with extension headers (for instance Destination Options). ip6tables works fine with conditions like --proto udp or --dport 109, even when the packet has extension headers. Netfilter clearly knows how to jump over Destination Options to find the UDP header. Now, I would like to use the u32 module to match a byte in the payload (say "I want the third byte of the payload to be 42). If the packet has no extension headers something like --u32 "48&0x0000ff00=0x2800"` (48 = 40 bytes for the IPv6 header + 8 for the UDP header) works fine, If the packet has a Destination Options, it no longer matches. I would like to write a rule that will work whether the packet has Destination Options or not. I do not find a way to tell Netfilter to parse until the UDP header (something that it is able to do, otherwise --dport 109 would not work) then to leave u32 parse the rest. I'm looking for a simple way, otherwise, as BatchyX mentions, I could write a kernel module doing what I want.

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  • Reconstruct a file from a TCP stream

    - by Abhishek Chanda
    I have a client and a server and a third box which sees all packets from the server to the client (but not the other way around). Now when the client requests a file from the server (over HTTP), the third box sees the response. I am trying to reconstruct the file there. I am using libpcap to capture TCP datagrams and trying to reconstruct the file there. Here is what I did Listen for packets on an interface Group all packets which have the same ACK number Sort the group based on SEQ number Extract data from each packet and combine them and write to the disk The problem is, the file thus generated is not exactly the same as the original file. Does everything sound correct here? Some more details: I am using C++ The packet data is being stored as std::vector<char> I did change the byte order while reading the ack number and seq number from the packet using ntohl I am not sure if I need to change the byte order for the data as well. I tried to reverse the data from each packet before combining them, even that did not work. Is there something I am missing?

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  • How Hacker Can Access VPS CentOS 6 content?

    - by user2118559
    Just want to understand. Please, correct mistakes and write advices Hacker can access to VPS: 1. Through (using) console terminal, for example, using PuTTY. To access, hacker need to know port number, username and password. Port number hacker can know scanning open ports and try to login. The only way to login as I understand need to know username and password. To block (make more difficult) port scanning, need to use iptables configure /etc/sysconfig/iptables. I followed this https://www.digitalocean.com/community/articles/how-to-setup-a-basic-ip-tables-configuration-on-centos-6 tutorial and got *nat :PREROUTING ACCEPT [87:4524] :POSTROUTING ACCEPT [77:4713] :OUTPUT ACCEPT [77:4713] COMMIT *mangle :PREROUTING ACCEPT [2358:200388] :INPUT ACCEPT [2358:200388] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [2638:477779] :POSTROUTING ACCEPT [2638:477779] COMMIT *filter :INPUT DROP [1:40] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [339:56132] -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -A INPUT -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG NONE -j DROP -A INPUT -p tcp -m tcp ! --tcp-flags FIN,SYN,RST,ACK SYN -m state --state NEW -j DROP -A INPUT -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG FIN,SYN,RST,PSH,ACK,URG -j DROP -A INPUT -i lo -j ACCEPT -A INPUT -p tcp -m tcp --dport 80 -j ACCEPT -A INPUT -p tcp -m tcp --dport 110 -j ACCEPT -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT -A INPUT -s 11.111.11.111/32 -p tcp -m tcp --dport 22 -j ACCEPT -A INPUT -p tcp -m tcp --dport 21 -j ACCEPT -A INPUT -s 11.111.11.111/32 -p tcp -m tcp --dport 21 -j ACCEPT COMMIT Regarding ports that need to be opened. If does not use ssl, then seems must leave open port 80 for website. Then for ssh (default 22) and for ftp (default 21). And set ip address, from which can connect. So if hacker uses other ip address, he can not access even knowing username and password? Regarding emails not sure. If I send email, using Gmail (Send mail as: (Use Gmail to send from your other email addresses)), then port 25 not necessary. For incoming emails at dynadot.com I use Email Forwarding. Does it mean that emails “does not arrive to VPS” (before arriving to VPS, emails are forwarded, for example to Gmail)? If emails does not arrive to VPS, then seems port 110 also not necessary. If use only ssl, must open port 443 and close port 80. Do not understand regarding port 3306 In PuTTY with /bin/netstat -lnp see Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 992/mysqld As understand it is for mysql. But does not remember that I have opened such port (may be when installed mysql, the port is opened automatically?). Mysql is installed on the same server, where all other content. Need to understand regarding port 3306 2. Also hacker may be able access console terminal through VPS hosting provider Control Panel (serial console emergency access). As understand only using console terminal (PuTTY, etc.) can make “global” changes (changes that can not modify with ftp). 3. Hacker can access to my VPS exploiting some hole in my php code and uploading, for example, Trojan. Unfortunately, faced situation that VPS was hacked. As understand it was because I used ZPanel. On VPS ( \etc\zpanel\panel\bin) ) found one php file, that was identified as Trojan by some virus scanners (at virustotal.com). Experimented with the file on local computer (wamp). And appears that hacker can see all content of VPS, rename, delete, upload etc. From my opinion, if in PuTTY use command like chattr +i /etc/php.ini then hacker could not be able to modify php.ini. Is there any other way to get into VPS?

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  • iptables 1.4 and passive FTP on custom port

    - by Cracky
    after the upgrade from debian squeeze to wheezy I've got a problem with passive FTP connection. I could narrow it to be iptables related, as I could connect via FTP w/o problems after adding my IP to the iptables ACCEPT rule. Before the upgrade I was able just to do modprobe nf_conntract_ftp ports=21332 and adding iptables -A THRU -p tcp --dport 21332 -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT now..it doesn't help anymore. The INPUT rule is being triggered as I can see in the counter, but the directory listing is the last thing it does. Setting up a passive-port range is the last thing I want to do, I dislike open ports. I also tried the trick with helper mod by adding following rule before the actual rule for 21332 iptables -A THRU -p tcp -i eth0 --dport 21332 -m state --state NEW -m helper --helper ftp-21332 -j ACCEPT but it doesn't help and is even not being triggered according to counter. The rule in the next line (w/o helper) is being triggered.. here some info: # iptables --version iptables v1.4.14 # lsmod |grep nf_ nf_nat_ftp 12460 0 nf_nat 18242 1 nf_nat_ftp nf_conntrack_ftp 12605 1 nf_nat_ftp nf_conntrack_ipv4 14078 32 nf_nat nf_defrag_ipv4 12483 1 nf_conntrack_ipv4 nf_conntrack 52720 7 xt_state,nf_conntrack_ipv4,xt_conntrack,nf_conntrack_ftp,nf_nat,nf_nat_ftp,xt_helper # uname -a Linux loki 3.2.0-4-amd64 #1 SMP Debian 3.2.46-1 x86_64 GNU/Linux # iptables-save # Generated by iptables-save v1.4.14 on Sun Jun 30 03:54:28 2013 *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :BLACKLIST - [0:0] :LOGDROP - [0:0] :SPAM - [0:0] :THRU - [0:0] :WEB - [0:0] :fail2ban-dovecot-pop3imap - [0:0] :fail2ban-pureftpd - [0:0] :fail2ban-ssh - [0:0] -A INPUT -p tcp -m multiport --dports 110,995,143,993 -j fail2ban-dovecot-pop3imap -A INPUT -p tcp -m multiport --dports 21,21332 -j fail2ban-pureftpd -A INPUT -p tcp -m multiport --dports 22 -j fail2ban-ssh -A INPUT -p tcp -m multiport --dports 110,995,143,993 -j fail2ban-dovecot-pop3imap -A INPUT -i lo -j ACCEPT -A INPUT -i eth0 -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG NONE -j DROP -A INPUT -i eth0 -p tcp -m tcp --tcp-flags FIN,SYN FIN,SYN -j DROP -A INPUT -i eth0 -p tcp -m tcp --tcp-flags SYN,RST SYN,RST -j DROP -A INPUT -i eth0 -p tcp -m tcp --tcp-flags FIN,RST FIN,RST -j DROP -A INPUT -i eth0 -p tcp -m tcp --tcp-flags FIN,ACK FIN -j DROP -A INPUT -i eth0 -p tcp -m tcp --tcp-flags ACK,URG URG -j DROP -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT -A INPUT -j BLACKLIST -A INPUT -j THRU -A INPUT -j LOGDROP -A OUTPUT -j ACCEPT -A OUTPUT -s 93.223.38.223/32 -j ACCEPT -A BLACKLIST -s 38.113.165.0/24 -j LOGDROP -A BLACKLIST -s 202.177.216.0/24 -j LOGDROP -A BLACKLIST -s 130.117.190.0/24 -j LOGDROP -A BLACKLIST -s 117.79.92.0/24 -j LOGDROP -A BLACKLIST -s 72.47.228.0/24 -j LOGDROP -A BLACKLIST -s 195.200.70.0/24 -j LOGDROP -A BLACKLIST -s 195.200.71.0/24 -j LOGDROP -A LOGDROP -m limit --limit 5/sec -j LOG --log-prefix drop_packet_ --log-level 7 -A LOGDROP -p tcp -m tcp --dport 25 -m limit --limit 2/sec -j LOG --log-prefix spam_blacklist --log-level 7 -A LOGDROP -p tcp -m tcp --dport 80 -m limit --limit 2/sec -j LOG --log-prefix web_blacklist --log-level 7 -A LOGDROP -p tcp -m tcp --dport 22 -m limit --limit 2/sec -j LOG --log-prefix ssh_blacklist --log-level 7 -A LOGDROP -j REJECT --reject-with icmp-host-prohibited -A THRU -p icmp -m limit --limit 1/sec -m icmp --icmp-type 8 -j ACCEPT -A THRU -i eth0 -p tcp -m tcp --dport 25 -j ACCEPT -A THRU -i eth0 -p udp -m udp --dport 53 -j ACCEPT -A THRU -i eth0 -p tcp -m tcp --dport 80 -j ACCEPT -A THRU -i eth0 -p tcp -m tcp --dport 110 -j ACCEPT -A THRU -i eth0 -p tcp -m tcp --dport 143 -j ACCEPT -A THRU -i eth0 -p tcp -m tcp --dport 465 -j ACCEPT -A THRU -i eth0 -p tcp -m tcp --dport 585 -j ACCEPT -A THRU -i eth0 -p tcp -m tcp --dport 993 -j ACCEPT -A THRU -i eth0 -p tcp -m tcp --dport 995 -j ACCEPT -A THRU -i eth0 -p tcp -m tcp --dport 2008 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT -A THRU -i eth0 -p tcp -m tcp --dport 10011 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT -A THRU -i eth0 -p tcp -m tcp --dport 21332 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT -A THRU -i eth0 -p tcp -m tcp --dport 30033 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT -A fail2ban-dovecot-pop3imap -j RETURN -A fail2ban-dovecot-pop3imap -j RETURN -A fail2ban-pureftpd -j RETURN -A fail2ban-pureftpd -j RETURN -A fail2ban-ssh -j RETURN -A fail2ban-ssh -j RETURN COMMIT # Completed on Sun Jun 30 03:54:28 2013 So, as I said, I have no problems with connecting when adding my IP to go through..but that's not a solution as noone except me can connect anymore~ If someone got an idea what the problem is, please help me! Thanks Cracky

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  • Is this proper OO design for C++?

    - by user121917
    I recently took a software processes course and this is my first time attempting OO design on my own. I am trying to follow OO design principles and C++ conventions. I attempted and gave up on MVC for this application, but I am trying to "decouple" my classes such that they can be easily unit-tested and so that I can easily change the GUI library used and/or the target OS. At this time, I have finished designing classes but have not yet started implementing methods. The function of the software is to log all packets sent and received, and display them on the screen (like WireShark, but for one local process only). The software accomplishes this by hooking the send() and recv() functions in winsock32.dll, or some other pair of analogous functions depending on what the intended Target is. The hooks add packets to SendPacketList/RecvPacketList. The GuiLogic class starts a thread which checks for new packets. When new packets are found, it utilizes the PacketFilter class to determine the formatting for the new packet, and then sends it to MainWindow, a native win32 window (with intent to later port to Qt).1 Full size image of UML class diagram Here are my classes in skeleton/header form (this is my actual code): class PacketModel { protected: std::vector<byte> data; int id; public: PacketModel(); PacketModel(byte* data, unsigned int size); PacketModel(int id, byte* data, unsigned int size); int GetLen(); bool IsValid(); //len >= sizeof(opcode_t) opcode_t GetOpcode(); byte* GetData(); //returns &(data[0]) bool GetData(byte* outdata, int maxlen); void SetData(byte* pdata, int len); int GetId(); void SetId(int id); bool ParseData(char* instr); bool StringRepr(char* outstr); byte& operator[] (const int index); }; class SendPacket : public PacketModel { protected: byte* returnAddy; public: byte* GetReturnAddy(); void SetReturnAddy(byte* addy); }; class RecvPacket : public PacketModel { protected: byte* callAddy; public: byte* GetCallAddy(); void SetCallAddy(byte* addy); }; //problem: packets may be added to list at any time by any number of threads //solution: critical section associated with each packet list class Synch { public: void Enter(); void Leave(); }; template<class PacketType> class PacketList { private: static const int MAX_STORED_PACKETS = 1000; public: static const int DEFAULT_SHOWN_PACKETS = 100; private: vector<PacketType> list; Synch synch; //wrapper for critical section public: void AddPacket(PacketType* packet); PacketType* GetPacket(int id); int TotalPackets(); }; class SendPacketList : PacketList<SendPacket> { }; class RecvPacketList : PacketList<RecvPacket> { }; class Target //one socket { bool Send(SendPacket* packet); bool Inject(RecvPacket* packet); bool InitSendHook(SendPacketList* sendList); bool InitRecvHook(RecvPacketList* recvList); }; class FilterModel { private: opcode_t opcode; int colorID; bool bFilter; char name[41]; }; class FilterFile { private: FilterModel filter; public: void Save(); void Load(); FilterModel* GetFilter(opcode_t opcode); }; class PacketFilter { private: FilterFile filters; public: bool IsFiltered(opcode_t opcode); bool GetName(opcode_t opcode, char* namestr); //return false if name does not exist COLORREF GetColor(opcode_t opcode); //return default color if no custom color }; class GuiLogic { private: SendPacketList sendList; RecvPacketList recvList; PacketFilter packetFilter; void GetPacketRepr(PacketModel* packet); void ReadNew(); void AddToWindow(); public: void Refresh(); //called from thread void GetPacketInfo(int id); //called from MainWindow }; I'm looking for a general review of my OO design, use of UML, and use of C++ features. I especially just want to know if I'm doing anything considerably wrong. From what I've read, design review is on-topic for this site (and off-topic for the Code Review site). Any sort of feedback is greatly appreciated. Thanks for reading this.

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  • Server-side Input

    - by Thomas
    Currently in my game, the client is nothing but a renderer. When input state is changed, the client sends a packet to the server and moves the player as if it were processing the input, but the server has the final say on the position. This generally works really well, except for one big problem: falling off edges. Basically, if a player is walking towards an edge, say a cliff, and stops right before going off the edge, sometimes a second later, he'll be teleported off of the edge. This is because the "I stopped pressing W" packet is sent after the server processes the information. Here's a lag diagram to help you understand what I mean: http://i.imgur.com/Prr8K.png I could just send a "W Pressed" packet each frame for the server to process, but that would seem to be a bandwidth-costly solution. Any help is appreciated!

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  • Sending state diffs (deltas) and unreliable connections

    - by spaceOwl
    We're building a realtime multiplayer game, in which each player is responsible for reporting its state on every iteration of the game loop. The state updates are broadcasted using unreliable UDP. To minimize state data sending, we've come up with a system that will send only deltas (whatever state data that was changed). This method however is flawed, since a lost packet will mean that other players will not receive the delta, making the game behave in an unexpected way. For example: Assume that state is comprised of: { positionX, positionY, health } Frame 1 - positionX changed --> send a packet with positionX only. Frame 2 - health changed // lost ! Frame 3 - positionY changed --> send a packet with positionY only. // Other players don't know about health change. How can one overcome this issue then? sending the entire data is not always feasible.

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  • FreeBSD 8.1 unstable network connection

    - by frankcheong
    I have three FreeBSD 8.1 running on three different hardware and therefore consist of different network adapter as well (bce, bge and igb). I found that the network connection is kind of unstable which I have tried to scp some 10MB file and found that I cannot always get the files completed successfully. I have further checked with my network admin and he claim that the problem is being caused by the network driver which cannot support the load whereby he tried to ping using huge packet size (around 15k) and my server will drop packet consistently at a regular interval. I found that this statement may not be valid since the three server is using three different network drive and it would be quite impossible that the same problem is being caused by three different network adapter and thus different network driver. Since then I have tried to tune up the performance by playing around with the /etc/sysctl.conf figures with no luck. kern.ipc.somaxconn=1024 kern.ipc.shmall=3276800 kern.ipc.shmmax=1638400000 # Security net.inet.ip.redirect=0 net.inet.ip.sourceroute=0 net.inet.ip.accept_sourceroute=0 net.inet.icmp.maskrepl=0 net.inet.icmp.log_redirect=0 net.inet.icmp.drop_redirect=1 net.inet.tcp.drop_synfin=1 # Security net.inet.udp.blackhole=1 net.inet.tcp.blackhole=2 # Required by pf net.inet.ip.forwarding=1 #Network Performance Tuning kern.ipc.maxsockbuf=16777216 net.inet.tcp.rfc1323=1 net.inet.tcp.sendbuf_max=16777216 net.inet.tcp.recvbuf_max=16777216 # Setting specifically for 1 or even 10Gbps network net.local.stream.sendspace=262144 net.local.stream.recvspace=262144 net.inet.tcp.local_slowstart_flightsize=10 net.inet.tcp.nolocaltimewait=1 net.inet.tcp.mssdflt=1460 net.inet.tcp.sendbuf_auto=1 net.inet.tcp.sendbuf_inc=16384 net.inet.tcp.recvbuf_auto=1 net.inet.tcp.recvbuf_inc=524288 net.inet.tcp.sendspace=262144 net.inet.tcp.recvspace=262144 net.inet.udp.recvspace=262144 kern.ipc.maxsockbuf=16777216 kern.ipc.nmbclusters=32768 net.inet.tcp.delayed_ack=1 net.inet.tcp.delacktime=100 net.inet.tcp.slowstart_flightsize=179 net.inet.tcp.inflight.enable=1 net.inet.tcp.inflight.min=6144 # Reduce the cache size of slow start connection net.inet.tcp.hostcache.expire=1 Our network admin also claim that they see quite a lot of network up and down from their cisco switch log while I cannot find any up down message inside the dmesg. Have further checked the netstat -s but dont have concrete idea. tcp: 133695291 packets sent 39408539 data packets (3358837321 bytes) 61868 data packets (89472844 bytes) retransmitted 24 data packets unnecessarily retransmitted 0 resends initiated by MTU discovery 50756141 ack-only packets (2148 delayed) 0 URG only packets 0 window probe packets 4372385 window update packets 39781869 control packets 134898031 packets received 72339403 acks (for 3357601899 bytes) 190712 duplicate acks 0 acks for unsent data 59339201 packets (3647021974 bytes) received in-sequence 114 completely duplicate packets (135202 bytes) 27 old duplicate packets 0 packets with some dup. data (0 bytes duped) 42090 out-of-order packets (60817889 bytes) 0 packets (0 bytes) of data after window 0 window probes 3953896 window update packets 64181 packets received after close 0 discarded for bad checksums 0 discarded for bad header offset fields 0 discarded because packet too short 45192 discarded due to memory problems 19945391 connection requests 1323420 connection accepts 0 bad connection attempts 0 listen queue overflows 0 ignored RSTs in the windows 21133581 connections established (including accepts) 21268724 connections closed (including 32737 drops) 207874 connections updated cached RTT on close 207874 connections updated cached RTT variance on close 132439 connections updated cached ssthresh on close 42392 embryonic connections dropped 72339338 segments updated rtt (of 69477829 attempts) 390871 retransmit timeouts 0 connections dropped by rexmit timeout 0 persist timeouts 0 connections dropped by persist timeout 0 Connections (fin_wait_2) dropped because of timeout 13990 keepalive timeouts 2 keepalive probes sent 13988 connections dropped by keepalive 173044 correct ACK header predictions 36947371 correct data packet header predictions 1323420 syncache entries added 0 retransmitted 0 dupsyn 0 dropped 1323420 completed 0 bucket overflow 0 cache overflow 0 reset 0 stale 0 aborted 0 badack 0 unreach 0 zone failures 1323420 cookies sent 0 cookies received 1864 SACK recovery episodes 18005 segment rexmits in SACK recovery episodes 26066896 byte rexmits in SACK recovery episodes 147327 SACK options (SACK blocks) received 87473 SACK options (SACK blocks) sent 0 SACK scoreboard overflow 0 packets with ECN CE bit set 0 packets with ECN ECT(0) bit set 0 packets with ECN ECT(1) bit set 0 successful ECN handshakes 0 times ECN reduced the congestion window udp: 5141258 datagrams received 0 with incomplete header 0 with bad data length field 0 with bad checksum 1 with no checksum 0 dropped due to no socket 129616 broadcast/multicast datagrams undelivered 0 dropped due to full socket buffers 0 not for hashed pcb 5011642 delivered 5016050 datagrams output 0 times multicast source filter matched sctp: 0 input packets 0 datagrams 0 packets that had data 0 input SACK chunks 0 input DATA chunks 0 duplicate DATA chunks 0 input HB chunks 0 HB-ACK chunks 0 input ECNE chunks 0 input AUTH chunks 0 chunks missing AUTH 0 invalid HMAC ids received 0 invalid secret ids received 0 auth failed 0 fast path receives all one chunk 0 fast path multi-part data 0 output packets 0 output SACKs 0 output DATA chunks 0 retransmitted DATA chunks 0 fast retransmitted DATA chunks 0 FR's that happened more than once to same chunk 0 intput HB chunks 0 output ECNE chunks 0 output AUTH chunks 0 ip_output error counter Packet drop statistics: 0 from middle box 0 from end host 0 with data 0 non-data, non-endhost 0 non-endhost, bandwidth rep only 0 not enough for chunk header 0 not enough data to confirm 0 where process_chunk_drop said break 0 failed to find TSN 0 attempt reverse TSN lookup 0 e-host confirms zero-rwnd 0 midbox confirms no space 0 data did not match TSN 0 TSN's marked for Fast Retran Timeouts: 0 iterator timers fired 0 T3 data time outs 0 window probe (T3) timers fired 0 INIT timers fired 0 sack timers fired 0 shutdown timers fired 0 heartbeat timers fired 0 a cookie timeout fired 0 an endpoint changed its cookiesecret 0 PMTU timers fired 0 shutdown ack timers fired 0 shutdown guard timers fired 0 stream reset timers fired 0 early FR timers fired 0 an asconf timer fired 0 auto close timer fired 0 asoc free timers expired 0 inp free timers expired 0 packet shorter than header 0 checksum error 0 no endpoint for port 0 bad v-tag 0 bad SID 0 no memory 0 number of multiple FR in a RTT window 0 RFC813 allowed sending 0 RFC813 does not allow sending 0 times max burst prohibited sending 0 look ahead tells us no memory in interface 0 numbers of window probes sent 0 times an output error to clamp down on next user send 0 times sctp_senderrors were caused from a user 0 number of in data drops due to chunk limit reached 0 number of in data drops due to rwnd limit reached 0 times a ECN reduced the cwnd 0 used express lookup via vtag 0 collision in express lookup 0 times the sender ran dry of user data on primary 0 same for above 0 sacks the slow way 0 window update only sacks sent 0 sends with sinfo_flags !=0 0 unordered sends 0 sends with EOF flag set 0 sends with ABORT flag set 0 times protocol drain called 0 times we did a protocol drain 0 times recv was called with peek 0 cached chunks used 0 cached stream oq's used 0 unread messages abandonded by close 0 send burst avoidance, already max burst inflight to net 0 send cwnd full avoidance, already max burst inflight to net 0 number of map array over-runs via fwd-tsn's ip: 137814085 total packets received 0 bad header checksums 0 with size smaller than minimum 0 with data size < data length 0 with ip length > max ip packet size 0 with header length < data size 0 with data length < header length 0 with bad options 0 with incorrect version number 1200 fragments received 0 fragments dropped (dup or out of space) 0 fragments dropped after timeout 300 packets reassembled ok 137813009 packets for this host 530 packets for unknown/unsupported protocol 0 packets forwarded (0 packets fast forwarded) 61 packets not forwardable 0 packets received for unknown multicast group 0 redirects sent 137234598 packets sent from this host 0 packets sent with fabricated ip header 685307 output packets dropped due to no bufs, etc. 52 output packets discarded due to no route 300 output datagrams fragmented 1200 fragments created 0 datagrams that can't be fragmented 0 tunneling packets that can't find gif 0 datagrams with bad address in header icmp: 0 calls to icmp_error 0 errors not generated in response to an icmp message Output histogram: echo reply: 305 0 messages with bad code fields 0 messages less than the minimum length 0 messages with bad checksum 0 messages with bad length 0 multicast echo requests ignored 0 multicast timestamp requests ignored Input histogram: destination unreachable: 530 echo: 305 305 message responses generated 0 invalid return addresses 0 no return routes ICMP address mask responses are disabled igmp: 0 messages received 0 messages received with too few bytes 0 messages received with wrong TTL 0 messages received with bad checksum 0 V1/V2 membership queries received 0 V3 membership queries received 0 membership queries received with invalid field(s) 0 general queries received 0 group queries received 0 group-source queries received 0 group-source queries dropped 0 membership reports received 0 membership reports received with invalid field(s) 0 membership reports received for groups to which we belong 0 V3 reports received without Router Alert 0 membership reports sent arp: 376748 ARP requests sent 3207 ARP replies sent 245245 ARP requests received 80845 ARP replies received 326090 ARP packets received 267712 total packets dropped due to no ARP entry 108876 ARP entrys timed out 0 Duplicate IPs seen ip6: 2226633 total packets received 0 with size smaller than minimum 0 with data size < data length 0 with bad options 0 with incorrect version number 0 fragments received 0 fragments dropped (dup or out of space) 0 fragments dropped after timeout 0 fragments that exceeded limit 0 packets reassembled ok 2226633 packets for this host 0 packets forwarded 0 packets not forwardable 0 redirects sent 2226633 packets sent from this host 0 packets sent with fabricated ip header 0 output packets dropped due to no bufs, etc. 8 output packets discarded due to no route 0 output datagrams fragmented 0 fragments created 0 datagrams that can't be fragmented 0 packets that violated scope rules 0 multicast packets which we don't join Input histogram: UDP: 2226633 Mbuf statistics: 962679 one mbuf 1263954 one ext mbuf 0 two or more ext mbuf 0 packets whose headers are not continuous 0 tunneling packets that can't find gif 0 packets discarded because of too many headers 0 failures of source address selection Source addresses selection rule applied: icmp6: 0 calls to icmp6_error 0 errors not generated in response to an icmp6 message 0 errors not generated because of rate limitation 0 messages with bad code fields 0 messages < minimum length 0 bad checksums 0 messages with bad length Histogram of error messages to be generated: 0 no route 0 administratively prohibited 0 beyond scope 0 address unreachable 0 port unreachable 0 packet too big 0 time exceed transit 0 time exceed reassembly 0 erroneous header field 0 unrecognized next header 0 unrecognized option 0 redirect 0 unknown 0 message responses generated 0 messages with too many ND options 0 messages with bad ND options 0 bad neighbor solicitation messages 0 bad neighbor advertisement messages 0 bad router solicitation messages 0 bad router advertisement messages 0 bad redirect messages 0 path MTU changes rip6: 0 messages received 0 checksum calculations on inbound 0 messages with bad checksum 0 messages dropped due to no socket 0 multicast messages dropped due to no socket 0 messages dropped due to full socket buffers 0 delivered 0 datagrams output netstat -m 516/5124/5640 mbufs in use (current/cache/total) 512/1634/2146/32768 mbuf clusters in use (current/cache/total/max) 512/1536 mbuf+clusters out of packet secondary zone in use (current/cache) 0/1303/1303/12800 4k (page size) jumbo clusters in use (current/cache/total/max) 0/0/0/6400 9k jumbo clusters in use (current/cache/total/max) 0/0/0/3200 16k jumbo clusters in use (current/cache/total/max) 1153K/9761K/10914K bytes allocated to network (current/cache/total) 0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters) 0/0/0 requests for jumbo clusters denied (4k/9k/16k) 0/8/6656 sfbufs in use (current/peak/max) 0 requests for sfbufs denied 0 requests for sfbufs delayed 0 requests for I/O initiated by sendfile 0 calls to protocol drain routines Anyone got an idea what might be the possible cause?

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  • Cant access a remote server due mistake by setting firewall rule

    - by LMIT
    I need help due a my silly mistake! So for long time i have a dedicate server hosted by register.it Usually i access remotly to this server (Windows 2008 server) by Terminal Server. Today i wanted to block one site that continually send request to my server. So i was adding a new rule in the firewall (the native firewall on windows 2008 server), as i did many time, but this time, probably i was sleeping with my brain i add a general rules that stop everything! So i cant access to the server anymore, as no any users can browse the sites, nothing is working because this rule block everything. I know that is a silly mistake, no need to tell me :) so please what i can do ? The only 1 thing that my provider let me is reboot the server by his control panel, but this not help me in any way because the firewall block me again. i have administrator username and password, so what i really can do ? there are some trick some tecnique, some expert guru that can help me in this very bad situation ? UPDATE i follow the Tony suggest and i did a NMAP to check if some ports are open but look like all closed: NMAP RESULT Starting Nmap 6.00 ( http://nmap.org ) at 2012-05-29 22:32 W. Europe Daylight Time NSE: Loaded 93 scripts for scanning. NSE: Script Pre-scanning. Initiating Parallel DNS resolution of 1 host. at 22:32 Completed Parallel DNS resolution of 1 host. at 22:33, 13.00s elapsed Initiating SYN Stealth Scan at 22:33 Scanning xxx.xxx.xxx.xxx [1000 ports] SYN Stealth Scan Timing: About 29.00% done; ETC: 22:34 (0:01:16 remaining) SYN Stealth Scan Timing: About 58.00% done; ETC: 22:34 (0:00:44 remaining) Completed SYN Stealth Scan at 22:34, 104.39s elapsed (1000 total ports) Initiating Service scan at 22:34 Initiating OS detection (try #1) against xxx.xxx.xxx.xxx Retrying OS detection (try #2) against xxx.xxx.xxx.xxx Initiating Traceroute at 22:34 Completed Traceroute at 22:35, 6.27s elapsed Initiating Parallel DNS resolution of 11 hosts. at 22:35 Completed Parallel DNS resolution of 11 hosts. at 22:35, 13.00s elapsed NSE: Script scanning xxx.xxx.xxx.xxx. Initiating NSE at 22:35 Completed NSE at 22:35, 0.00s elapsed Nmap scan report for xxx.xxx.xxx.xxx Host is up. All 1000 scanned ports on xxx.xxx.xxx.xxx are filtered Too many fingerprints match this host to give specific OS details TRACEROUTE (using proto 1/icmp) HOP RTT ADDRESS 1 ... ... ... 13 ... 30 NSE: Script Post-scanning. Read data files from: D:\Program Files\Nmap OS and Service detection performed. Please report any incorrect results at http://nmap.org/submit/ . Nmap done: 1 IP address (1 host up) scanned in 145.08 seconds Raw packets sent: 2116 (96.576KB) | Rcvd: 61 (4.082KB) Question: The provider locally can access by username and password ?

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  • Webserver Responses Hanging

    - by drscroogemcduck
    From some networks requesting certain images on our webserver is very flakey. I've looked at tcpdumps on both sides and the server sends back part of the file and the client ACKs the TCP packet but the server never receives the ACK. The servers view: 41 19.941136 212.169.34.114 209.20.73.85 TCP 52456 > http [SYN] Seq=0 Win=8192 Len=0 MSS=1460 WS=2 42 19.941136 209.20.73.85 212.169.34.114 TCP http > 52456 [SYN, ACK] Seq=0 Ack=1 Win=5440 Len=0 MSS=1360 46 20.041142 212.169.34.114 209.20.73.85 TCP 52456 > http [ACK] Seq=1 Ack=1 Win=65280 Len=0 47 20.045142 212.169.34.114 209.20.73.85 HTTP GET /map/map/s+74-WBkWk0aR28Yy-YjXA== HTTP/1.1 48 20.045142 209.20.73.85 212.169.34.114 TCP http > 52456 [ACK] Seq=1 Ack=522 Win=6432 Len=0 49 20.045142 209.20.73.85 212.169.34.114 TCP [TCP segment of a reassembled PDU] (Part of the content of the image 2720 bytes. i assume it is reassembled in tcpdump and it is fragmented over the wire.) ** never receives the ACK sent in frame 282 and will eventually resend the tcp segment ** The clients view: 274 26.161773 10.0.16.67 209.20.73.85 TCP 52456 > http [SYN] Seq=0 Win=8192 Len=0 MSS=1460 WS=2 276 26.262867 209.20.73.85 10.0.16.67 TCP http > 52456 [SYN, ACK] Seq=0 Ack=1 Win=5440 Len=0 MSS=1360 277 26.263255 10.0.16.67 209.20.73.85 TCP 52456 > http [ACK] Seq=1 Ack=1 Win=65280 Len=0 278 26.265193 10.0.16.67 209.20.73.85 HTTP GET /map/map/s+74-WBkWk0aR28Yy-YjXA== HTTP/1.1 279 26.365562 209.20.73.85 10.0.16.67 TCP http > 52456 [ACK] Seq=1 Ack=522 Win=6432 Len=0 280 26.368002 209.20.73.85 10.0.16.67 TCP [TCP segment of a reassembled PDU] (Part of the content of the image. Only 1400 bytes.) 282 26.571380 10.0.16.67 209.20.73.85 TCP 52456 > http [ACK] Seq=522 Ack=1361 Win=65280 Len=0 The network we are having trouble with is NATd. Is there any kind of explanation for this weirdness?

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  • What info is really useful in my iptables log and how do I disable the useless bits?

    - by anthony01
    In my iptables rules files, I entered this at the end: -A INPUT -j LOG --log-level 4 --log-ip-options --log-prefix "iptables: " I DROP everything besides INPUT for SSH (port 22) I have a web server and when I try to connect to it through my browser, through a forbidden port number (on purpose), I get something like that in my iptables.log Sep 24 14:05:57 myserver kernel: [xx.xx] iptables: IN=eth0 OUT= MAC=aa:bb:cc SRC=yy.yy.yy.yy DST=xx.xx.xx.xx LEN=64 TOS=0x00 PREC=0x00 TTL=54 ID=59351 DF PROTO=TCP SPT=63776 DPT=1999 WINDOW=65535 RES=0x00 SYN URGP=0 Sep 24 14:06:01 myserver kernel: [xx.xx] iptables: IN=eth0 OUT= MAC=aa:bb:cc SRC= yy.yy.yy.yy DST=xx.xx.xx.xx LEN=48 TOS=0x00 PREC=0x00 TTL=54 ID=63377 DF PROTO=TCP SPT=63776 DPT=1999 WINDOW=65535 RES=0x00 SYN URGP=0 Sep 24 14:06:09 myserver kernel: [xx.xx] iptables: IN=eth0 OUT= MAC=aa:bb:cc SRC=yy.yy.yy.yy DST=xx.xx.xx.xx LEN=48 TOS=0x00 PREC=0x00 TTL=54 ID=55025 DF PROTO=TCP SPT=63776 DPT=1999 WINDOW=65535 RES=0x00 SYN URGP=0 Sep 24 14:06:25 myserver kernel: [xx.xx] iptables: IN=eth0 OUT= MAC=aa:bb:cc SRC=yy.yy.yy.yy DST=xx.xx.xx.xx LEN=48 TOS=0x00 PREC=0x00 TTL=54 ID=54521 DF PROTO=TCP SPT=63776 DPT=1999 WINDOW=65535 RES=0x00 SYN URGP=0 Sep 24 14:06:55 myserver kernel: [xx.xx] iptables: IN=eth0 OUT= MAC=aa:bb:cc SRC=yy.yy.yy.yy DST=xx.xx.xx.xx LEN=100 TOS=0x00 PREC=0x00 TTL=54 ID=35050 PROTO=TCP SPT=63088 DPT=22 WINDOW=33304 RES=0x00 ACK PSH URGP=0 Sep 24 14:06:55 myserver kernel: [xx.xx] iptables: IN=eth0 OUT= MAC=aa:bb:cc SRC=yy.yy.yy.yy DST=xx.xx.xx.xx LEN=52 TOS=0x00 PREC=0x00 TTL=54 ID=14076 PROTO=TCP SPT=63088 DPT=22 WINDOW=33264 RES=0x00 ACK URGP=0 Sep 24 14:06:55 myserver kernel: [xx.xx] iptables: IN=eth0 OUT= MAC=aa:bb:cc SRC=yy.yy.yy.yy DST=xx.xx.xx.xx LEN=52 TOS=0x00 PREC=0x00 TTL=54 ID=5277 PROTO=TCP SPT=63088 DPT=22 WINDOW=33248 RES=0x00 ACK URGP=0 Sep 24 14:06:56 myserver kernel: [xx.xx] iptables: IN=eth0 OUT= MAC=aa:bb:cc SRC=yy.yy.yy.yy DST=xx.xx.xx.xx LEN=100 TOS=0x00 PREC=0x00 TTL=54 ID=25501 PROTO=TCP SPT=63088 DPT=22 WINDOW=33304 RES=0x00 ACK PSH URGP=0 As you can see, I typed xx.xx.xx.xx:1999 in my browser, and it tried to connect until it timed out. 1) There are many similar lines for just one event. Do you think I need all of them? How would I avoid duplicates? 2) The last 4 lines are for my port 22. But since I allow port 22 INPUT for my web server, why are they here? 3) Do I need info like LEN,TOS,PREC and others? I'm trying to find a page that explains them one by one, by I can't find anything.

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  • IP address spoofing using Source Routing

    - by iamrohitbanga
    With IP options we can specify the route we want an IP packet to take while connecting to a server. If we know that a particular server provides some extra functionality based on the IP address can we not utilize this by spoofing an IP packet so that the source IP address is the privileged IP address and one of the hosts on the Source Routing is our own. So if the privileged IP address is x1 and server IP address is x2 and my own IP address is x3. I send a packet from x1 to x2 which is supposed to pass through x3. x1 does not actually send the packet. It is just that x2 thinks the packet came from x1 via x3. Now in response if x2 uses the same routing policy (as a matter of courtesy to x1) then all packets would be received by x3. Will the destination typically use the same IP address sequences as specified in the routing header so that packets coming from the server pass through my IP where I can get the required information? Can we not spoof a TCP connection in the above case? Is this attack used in practice?

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  • How to save image drawn on a JPanel?

    - by swift
    I have a panel with transparent background which i use to draw an image. now problem here is when i draw anything on panel and save the image as a JPEG file its saving the image with black background but i want it to be saved as same, as i draw on the panel. what should be done for this? plz guide me j Client.java public class Client extends Thread { static DatagramSocket datasocket; static DatagramSocket socket; Point point; Whiteboard board; Virtualboard virtualboard; JLayeredPane layerpane; BufferedImage image; public Client(DatagramSocket datasocket) { Client.datasocket=datasocket; } //This function is responsible to connect to the server public static void connect() { try { socket=new DatagramSocket (9000); //client connection socket port= 9000 datasocket=new DatagramSocket (9005); //client data socket port= 9002 ByteArrayOutputStream baos=new ByteArrayOutputStream(); DataOutputStream dos=new DataOutputStream(baos); //this is to tell server that this is a connection request dos.writeChar('c'); dos.close(); byte[]data=baos.toByteArray(); //Server IP address InetAddress ip=InetAddress.getByName("10.123.97.154"); //create the UDP packet DatagramPacket packet=new DatagramPacket(data, data.length,ip , 8000); socket.send(packet); Client client=new Client(datasocket); client.createFrame(); client.run(); } catch(Exception e) { e.printStackTrace(); } } //This function is to create the JFrame public void createFrame() { JFrame frame=new JFrame("Whiteboard"); frame.setVisible(true); frame.setBackground(Color.black); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(680,501); frame.addWindowListener(new WindowAdapter() { public void windowOpened(WindowEvent e) {} public void windowClosing(WindowEvent e) { close(); } }); layerpane=frame.getLayeredPane(); board= new Whiteboard(datasocket); image = new BufferedImage(590,463, BufferedImage.TYPE_INT_ARGB); board.setBounds(74,2,590,463); board.setImage(image); virtualboard=new Virtualboard(); virtualboard.setImage(image); virtualboard.setBounds(74,2,590,463); layerpane.add(virtualboard,new Integer(2));//Panel where remote user draws layerpane.add(board,new Integer(3)); layerpane.add(board.colourButtons(),new Integer(1)); layerpane.add(board.shapeButtons(),new Integer(0)); //frame.add(paper.addButtons(),BorderLayout.WEST); } /* * This function is overridden from the thread class * This function listens for incoming packets from the server * which contains the points drawn by the other client */ public void run () { while (true) { try { byte[] buffer = new byte[512]; DatagramPacket packet = new DatagramPacket(buffer, buffer.length); datasocket.receive(packet); InputStream in=new ByteArrayInputStream(packet.getData(), packet.getOffset(),packet.getLength()); DataInputStream din=new DataInputStream(in); int x=din.readInt(); int y=din.readInt(); String varname=din.readLine(); String var[]=varname.split("-",4); point=new Point(x,y); virtualboard.addPoint(point, var[0], var[1],var[2],var[3]); } catch (IOException ex) { ex.printStackTrace(); } } } //This function is to broadcast the newly drawn point to the server public void broadcast (Point p,String varname,String shape,String event, String color) { try { ByteArrayOutputStream baos=new ByteArrayOutputStream(); DataOutputStream dos=new DataOutputStream(baos); dos.writeInt(p.x); dos.writeInt(p.y); dos.writeBytes(varname); dos.writeBytes("-"); dos.writeBytes(shape); dos.writeBytes("-"); dos.writeBytes(event); dos.writeBytes("-"); dos.writeBytes(color); dos.close(); byte[]data=baos.toByteArray(); InetAddress ip=InetAddress.getByName("10.123.97.154"); DatagramPacket packet=new DatagramPacket(data, data.length,ip , 8002); datasocket.send(packet); } catch (Exception e) { e.printStackTrace(); } } //This function is to close the client's connection with the server public void close() { try { ByteArrayOutputStream baos=new ByteArrayOutputStream(); DataOutputStream dos=new DataOutputStream(baos); //This is to tell server that this is request to remove the client dos.writeChar('r'); dos.close(); byte[]data=baos.toByteArray(); //Server IP address InetAddress ip=InetAddress.getByName("10.123.97.154"); DatagramPacket packet=new DatagramPacket(data, data.length,ip , 8000); socket.send(packet); System.out.println("closed"); } catch(Exception e) { e.printStackTrace(); } } public static void main(String[] args) throws Exception { connect(); } } Whiteboard.java class Whiteboard extends JPanel implements MouseListener,MouseMotionListener,ActionListener,KeyListener { BufferedImage image; Boolean tooltip=false; int post; String shape; String selectedcolor="black"; Color color=Color.black; //Color color=Color.white; Point start; Point end; Point mp; Point tip; int keycode; String fillshape; Point fillstart=new Point(); Point fillend=new Point(); int noofside; Button r=new Button("rect"); Button rectangle=new Button("rect"); Button line=new Button("line"); Button roundrect=new Button("roundrect"); Button polygon=new Button("poly"); Button text=new Button("text"); JButton save=new JButton("Save"); Button elipse=new Button("elipse"); ImageIcon fillicon=new ImageIcon("images/fill.jpg"); JButton fill=new JButton(fillicon); ImageIcon erasericon=new ImageIcon("images/eraser.gif"); JButton erase=new JButton(erasericon); JButton[] colourbutton=new JButton[28]; String selected; Point label; String key=""; int ex,ey;//eraser DatagramSocket dataSocket; JButton button = new JButton("test"); Client client; Boolean first; int w,h; public Whiteboard(DatagramSocket dataSocket) { try { UIManager.setLookAndFeel( UIManager.getCrossPlatformLookAndFeelClassName()); } catch (Exception e) { e.printStackTrace(); } setLayout(null); setOpaque(false); setBackground(new Color(237,237,237)); this.dataSocket=dataSocket; client=new Client(dataSocket); addKeyListener(this); addMouseListener(this); addMouseMotionListener(this); setBorder(BorderFactory.createLineBorder(Color.black)); } public void paintComponent(Graphics g) { try { super.paintComponent(g); g.drawImage(image, 0, 0, this); Graphics2D g2 = (Graphics2D)g; if(color!=null) g2.setPaint(color); if(start!=null && end!=null) { if(selected==("elipse")) g2.drawOval(start.x, start.y,(end.x-start.x),(end.y-start.y)); else if(selected==("rect")) g2.drawRect(start.x, start.y, (end.x-start.x),(end.y-start.y)); else if(selected==("rrect")) g2.drawRoundRect(start.x, start.y, (end.x-start.x),(end.y-start.y),11,11); else if(selected==("line")) g2.drawLine(start.x,start.y,end.x,end.y); else if(selected==("poly")) { g2.drawLine(start.x,start.y,end.x,end.y); client.broadcast(start, "start", "poly", "drag", selectedcolor); client.broadcast(end, "end", "poly", "drag", selectedcolor); } } if(tooltip==true) { System.out.println(selected); if(selected=="text") { g2.drawString("|", tip.x, tip.y-5); g2.drawString("Click to add text", tip.x+10, tip.y+23); g2.drawString("__", label.x+post, label.y); } if(selected=="erase") { g2.setPaint(new Color(237,237,237)); g2.fillRect(tip.x-10,tip.y-10,10,10); g2.setPaint(color); g2.drawRect(tip.x-10,tip.y-10,10,10); } } } catch(Exception e) {} } //Function to draw the shape on image public void draw() { Graphics2D g2 = (Graphics2D) image.createGraphics(); Font font=new Font("Times New Roman",Font.PLAIN,14); g2.setFont(font); g2.setPaint(color); if(start!=null && end!=null) { if(selected=="line") g2.drawLine(start.x, start.y, end.x, end.y); else if(selected=="elipse") g2.drawOval(start.x, start.y, (end.x-start.x),(end.y-start.y)); else if(selected=="rect") g2.drawRect(start.x, start.y, (end.x-start.x),(end.y-start.y)); else if(selected==("rrect")) g2.drawRoundRect(start.x, start.y, (end.x-start.x),(end.y-start.y),11,11); else if(selected==("poly")) { g2.drawLine(start.x,start.y,end.x,end.y); client.broadcast(start, "start", "poly", "release", selectedcolor); client.broadcast(end, "end", "poly", "release", selectedcolor); } fillstart=start; fillend=end; fillshape=selected; } if(selected!="poly") { start=null; end=null; } if(label!=null) { if(selected==("text")) { g2.drawString(key,label.x,label.y); client.broadcast(label, key, "text", "release", selectedcolor); } } repaint(); g2.dispose(); } //Function which provides the erase functionality public void erase() { Graphics2D pic=(Graphics2D) image.createGraphics(); Color erasecolor=new Color(237,237,237); pic.setPaint(erasecolor); if(start!=null) pic.fillRect(start.x-10, start.y-10, 10, 10); } //To set the size of the image public void setImage(BufferedImage image) { this.image = image; } //Function to add buttons into the panel, calling this function returns a panel public JPanel shapeButtons() { JPanel shape=new JPanel(); shape.setBackground(new Color(181, 197, 210)); shape.setLayout(new GridLayout(5,2,2,4)); shape.setBounds(0, 2, 74, 166); rectangle.addActionListener(this); rectangle.setToolTipText("Rectangle"); line.addActionListener( this); line.setToolTipText("Line"); erase.addActionListener(this); erase.setToolTipText("Eraser"); roundrect.addActionListener(this); roundrect.setToolTipText("Round edge Rectangle"); polygon.addActionListener(this); polygon.setToolTipText("Polygon"); text.addActionListener(this); text.setToolTipText("Text"); fill.addActionListener(this); fill.setToolTipText("Fill with colour"); elipse.addActionListener(this); elipse.setToolTipText("Elipse"); save.addActionListener(this); shape.add(elipse); shape.add(rectangle); shape.add(roundrect); shape.add(polygon); shape.add(line); shape.add(text); shape.add(fill); shape.add(erase); shape.add(save); return shape; } public JPanel colourButtons() { JPanel colourbox=new JPanel(); colourbox.setBackground(new Color(181, 197, 210)); colourbox.setLayout(new GridLayout(8,2,8,8)); colourbox.setBounds(0,323,70,140); //colourbox.add(empty); for(int i=0;i<16;i++) { colourbutton[i]=new JButton(); colourbox.add(colourbutton[i]); if(i==0) colourbutton[0].setBackground(Color.black); else if(i==1) colourbutton[1].setBackground(Color.white); else if(i==2) colourbutton[2].setBackground(Color.red); else if(i==3) colourbutton[3].setBackground(Color.orange); else if(i==4) colourbutton[4].setBackground(Color.blue); else if(i==5) colourbutton[5].setBackground(Color.green); else if(i==6) colourbutton[6].setBackground(Color.pink); else if(i==7) colourbutton[7].setBackground(Color.magenta); else if(i==8) colourbutton[8].setBackground(Color.cyan); else if(i==9) colourbutton[9].setBackground(Color.black); else if(i==10) colourbutton[10].setBackground(Color.yellow); else if(i==11) colourbutton[11].setBackground(new Color(131,168,43)); else if(i==12) colourbutton[12].setBackground(new Color(132,0,210)); else if(i==13) colourbutton[13].setBackground(new Color(193,17,92)); else if(i==14) colourbutton[14].setBackground(new Color(129,82,50)); else if(i==15) colourbutton[15].setBackground(new Color(64,128,128)); colourbutton[i].addActionListener(this); } return colourbox; } public void fill() { if(selected=="fill") { Graphics2D g2 = (Graphics2D) image.getGraphics(); g2.setPaint(color); System.out.println("Fill"); if(fillshape=="elipse") g2.fillOval(fillstart.x, fillstart.y, (fillend.x-fillstart.x),(fillend.y-fillstart.y)); else if(fillshape=="rect") g2.fillRect(fillstart.x, fillstart.y, (fillend.x-fillstart.x),(fillend.y-fillstart.y)); else if(fillshape==("rrect")) g2.fillRoundRect(fillstart.x, fillstart.y, (fillend.x-fillstart.x),(fillend.y-fillstart.y),11,11); // else if(fillshape==("poly")) // g2.drawPolygon(x,y,2); } repaint(); } //To save the image drawn public void save() { try { ByteArrayOutputStream bos = new ByteArrayOutputStream(); JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(bos); JFileChooser fc = new JFileChooser(); fc.showSaveDialog(this); encoder.encode(image); byte[] jpgData = bos.toByteArray(); FileOutputStream fos = new FileOutputStream(fc.getSelectedFile()+".jpeg"); fos.write(jpgData); fos.close(); //add replce confirmation here } catch (IOException e) { System.out.println(e); } } public void mouseClicked(MouseEvent e) { } @Override public void mouseEntered(MouseEvent e) { } public void mouseExited(MouseEvent arg0) { } public void mousePressed(MouseEvent e) { if(selected=="line"||selected=="text") { start=e.getPoint(); client.broadcast(start,"start", selected,"press", selectedcolor); } else if(selected=="elipse"||selected=="rect"||selected=="rrect") mp = e.getPoint(); else if(selected=="poly") { if(first==true) { start=e.getPoint(); //client.broadcast(start,"start", selected,"press", selectedcolor); } else if(first==false) { end=e.getPoint(); repaint(); //client.broadcast(end,"end", selected,"press", selectedcolor); } } else if(selected=="erase") { start=e.getPoint(); erase(); } } public void mouseReleased(MouseEvent e) { if(selected=="text") { System.out.println("Reset"); key=""; post=0; label=new Point(); label=e.getPoint(); grabFocus(); } if(start!=null && end!=null) { if(selected=="line") { end=e.getPoint(); client.broadcast(end,"end", selected,"release", selectedcolor); draw(); } else if(selected=="elipse"||selected=="rect"||selected=="rrect") { end.x = Math.max(mp.x,e.getX()); end.y = Math.max(mp.y,e.getY()); client.broadcast(end,"end", selected,"release", selectedcolor); draw(); } else if(selected=="poly") { draw(); first=false; start=end; end=null; } } } public void mouseDragged(MouseEvent e) { if(end==null) end = new Point(); if(start==null) start = new Point(); if(selected=="line") { end=e.getPoint(); client.broadcast(end,"end", selected,"drag", selectedcolor); } else if(selected=="erase") { start=e.getPoint(); erase(); client.broadcast(start,"start", selected,"drag", selectedcolor); } else if(selected=="elipse"||selected=="rect"||selected=="rrect") { start.x = Math.min(mp.x,e.getX()); start.y = Math.min(mp.y,e.getY()); end.x = Math.max(mp.x,e.getX()); end.y = Math.max(mp.y,e.getY()); client.broadcast(start,"start", selected,"drag", selectedcolor); client.broadcast(end,"end", selected,"drag", selectedcolor); } else if(selected=="poly") end=e.getPoint(); System.out.println(tooltip); if(tooltip==true) { if(selected=="erase") { Graphics2D g2=(Graphics2D) getGraphics(); tip=e.getPoint(); g2.drawRect(tip.x-10,tip.y-10,10,10); } } repaint(); } public void mouseMoved(MouseEvent e) { if(selected=="text" ||selected=="erase") { tip=new Point(); tip=e.getPoint(); tooltip=true; repaint(); } } public void actionPerformed(ActionEvent e) { if(e.getSource()==elipse) selected="elipse"; else if(e.getSource()==line) selected="line"; else if(e.getSource()==rectangle) selected="rect"; else if(e.getSource()==erase) { selected="erase"; tooltip=true; System.out.println(selected); erase(); } else if(e.getSource()==roundrect) selected="rrect"; else if(e.getSource()==polygon) { selected="poly"; first=true; start=null; } else if(e.getSource()==text) { selected="text"; tooltip=true; } else if(e.getSource()==fill) { selected="fill"; fill(); } else if(e.getSource()==save) save(); if(e.getSource()==colourbutton[0]) { color=Color.black; selectedcolor="black"; } else if(e.getSource()==colourbutton[1]) { color=Color.white; selectedcolor="white"; } else if(e.getSource()==colourbutton[2]) { color=Color.red; selectedcolor="red"; } else if(e.getSource()==colourbutton[3]) { color=Color.orange; selectedcolor="orange"; } else if(e.getSource()==colourbutton[4]) { selectedcolor="blue"; color=Color.blue; } else if(e.getSource()==colourbutton[5]) { selectedcolor="green"; color=Color.green; } else if(e.getSource()==colourbutton[6]) { selectedcolor="pink"; color=Color.pink; } else if(e.getSource()==colourbutton[7]) { selectedcolor="magenta"; color=Color.magenta; } else if(e.getSource()==colourbutton[8]) { selectedcolor="cyan"; color=Color.cyan; } } @Override public void keyPressed(KeyEvent e) { //System.out.println(e.getKeyChar()+" : "+e.getKeyCode()); if(label!=null) { if(e.getKeyCode()==10) //Check for Enter key { label.y=label.y+14; key=""; post=0; repaint(); } else if(e.getKeyCode()==8) //Backspace { try{ Graphics2D g2 = (Graphics2D) image.getGraphics(); g2.setPaint(new Color(237,237,237)); g2.fillRect(label.x+post-7, label.y-13, 14, 17); if(post>0) post=post-6; keycode=0; key=key.substring(0, key.length()-1); System.out.println(key.substring(0, key.length())); repaint(); Point broadcastlabel=new Point(); broadcastlabel.x=label.x+post-7; broadcastlabel.y=label.y-13; client.broadcast(broadcastlabel, key, "text", "backspace", selectedcolor); } catch(Exception ex) {} } //Block invalid keys else if(!(e.getKeyCode()>=16 && e.getKeyCode()<=20 || e.getKeyCode()>=112 && e.getKeyCode()<=123 || e.getKeyCode()>=33 && e.getKeyCode()<=40 || e.getKeyCode()>=144 && e.getKeyCode()<=145 || e.getKeyCode()>=524 && e.getKeyCode()<=525 ||e.getKeyCode()==27||e.getKeyCode()==155 ||e.getKeyCode()==127)) { key=key+e.getKeyChar(); post=post+6; draw(); } } } @Override public void keyReleased(KeyEvent e) { } @Override public void keyTyped(KeyEvent e) { } } class Button extends JButton { String name; int i; public Button(String name) { this.name=name; try { UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); } catch (Exception e) { e.printStackTrace(); } } public Button(int i) { this.i=i; } public void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D)g; g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); //g2.setStroke(new BasicStroke(1.2f)); if (name == "line") g.drawLine(5,5,30,30); if (name == "elipse") g.drawOval(5,7,25,20); if (name== "rect") g.drawRect(5,5,25,23); if (name== "roundrect") g.drawRoundRect(5,5,25,23,10,10); int a[]=new int[]{20,9,20,23,20}; int b[]=new int[]{9,23,25,20,9}; if (name== "poly") g.drawPolyline(a, b, 5); if (name== "text") g.drawString("Text",8, 24); } }

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  • DSA signature verification input

    - by calccrypto
    What is the data inputted into DSA when PGP signs a message? From RFC4880, i found A Signature packet describes a binding between some public key and some data. The most common signatures are a signature of a file or a block of text, and a signature that is a certification of a User ID. im not sure if it is the entire public key, just the public key packet, or some other derivative of a pgp key packet. whatever it is, i cannot get the DSA signature to verify here is a sample im testing my program on: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 abcd -----BEGIN PGP SIGNATURE----- Version: BCPG v1.39 iFkEARECABkFAk0z65ESHGFiYyAodGVzdCBrZXkpIDw+AAoJEC3Jkh8+bnkusO0A oKG+HPF2Qrsth2zS9pK+eSCBSypOAKDBgC2Z0vf2EgLiiNMk8Bxpq68NkQ== =gq0e -----END PGP SIGNATURE----- Dumped from pgpdump.net Old: Signature Packet(tag 2)(89 bytes) Ver 4 - new Sig type - Signature of a canonical text document(0x01). Pub alg - DSA Digital Signature Algorithm(pub 17) Hash alg - SHA1(hash 2) Hashed Sub: signature creation time(sub 2)(4 bytes) Time - Mon Jan 17 07:11:13 UTC 2011 Hashed Sub: signer's User ID(sub 28)(17 bytes) User ID - abc (test key) <> Sub: issuer key ID(sub 16)(8 bytes) Key ID - 0x2DC9921F3E6E792E Hash left 2 bytes - b0 ed DSA r(160 bits) - a1 be 1c f1 76 42 bb 2d 87 6c d2 f6 92 be 79 20 81 4b 2a 4e DSA s(160 bits) - c1 80 2d 99 d2 f7 f6 12 02 e2 88 d3 24 f0 1c 69 ab af 0d 91 -> hash(DSA q bits) and the public key for it is: -----BEGIN PGP PUBLIC KEY BLOCK----- Version: BCPG v1.39 mOIETTPqeBECALx+i9PIc4MB2DYXeqsWUav2cUtMU1N0inmFHSF/2x0d9IWEpVzE kRc30PvmEHI1faQit7NepnHkkphrXLAoZukAoNP3PB8NRQ6lRF6/6e8siUgJtmPL Af9IZOv4PI51gg6ICLKzNO9i3bcUx4yeG2vjMOUAvsLkhSTWob0RxWppo6Pn6MOg dMQHIM5sDH0xGN0dOezzt/imAf9St2B0HQXVfAAbveXBeRoO7jj/qcGx6hWmsKUr BVzdQhBk7Sku6C2KlMtkbtzd1fj8DtnrT8XOPKGp7/Y7ASzRtBFhYmMgKHRlc3Qg a2V5KSA8PohGBBMRAgAGBQJNM+p5AAoJEC3Jkh8+bnkuNEoAnj2QnqGtdlTgUXCQ Fyvwk5wiLGPfAJ4jTGTL62nWzsgrCDIMIfEG2shm8bjMBE0z6ngQAgCUlP7AlfO4 XuKGVCs4NvyBpd0KA0m0wjndOHRNSIz44x24vLfTO0GrueWjPMqRRLHO8zLJS/BX O/BHo6ypjN87Af0VPV1hcq20MEW2iujh3hBwthNwBWhtKdPXOndJGZaB7lshLJuW v9z6WyDNXj/SBEiV1gnPm0ELeg8Syhy5pCjMAgCFEc+NkCzcUOJkVpgLpk+VLwrJ /Wi9q+yCihaJ4EEFt/7vzqmrooXWz2vMugD1C+llN6HkCHTnuMH07/E/2dzciEYE GBECAAYFAk0z6nkACgkQLcmSHz5ueS7NTwCdED1P9NhgR2LqwyS+AEyqlQ0d5joA oK9xPUzjg4FlB+1QTHoOhuokxxyN =CTgL -----END PGP PUBLIC KEY BLOCK----- the public key packet of the key is mOIETTPqeBECALx+i9PIc4MB2DYXeqsWUav2cUtMU1N0inmFHSF/2x0d9IWEpVzEkRc30PvmEHI1faQi t7NepnHkkphrXLAoZukAoNP3PB8NRQ6lRF6/6e8siUgJtmPLAf9IZOv4PI51gg6ICLKzNO9i3bcUx4ye G2vjMOUAvsLkhSTWob0RxWppo6Pn6MOgdMQHIM5sDH0xGN0dOezzt/imAf9St2B0HQXVfAAbveXBeRoO 7jj/qcGx6hWmsKUrBVzdQhBk7Sku6C2KlMtkbtzd1fj8DtnrT8XOPKGp7/Y7ASzR in radix 64 i have tried many different combinations of sha1(< some data + 'abcd'),but the calculated value v never equals r, of the signature i know that the pgp implementation i used to create the key and signature is correct. i also know that my DSA implementation and PGP key data extraction program are correct. thus, the only thing left is the data to hash. what is the correct data to be hashed?

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  • Processing incorrect mac addresses from 802.11 frames with pcap

    - by Quentin Swain
    I'm working throurgh a project with pcap and wireless. Following an example posted in response to oe of my earlier questions I am trying to extract the mac addresses from wireless frames. I have created structures for the radiotap header and a basic management frame. For some reason when it comes to trying to output the mac addresses I am printing out the wrong data. When I compare to wireshark I don't see why the radio tap data is printing out correctly but the mac addresses are not. I don't see any additional padding in the hex dump that wireshark displays when i look at the packets and compare the packets that I have captured. I am somewhat famialar with c but not an expert so maybe I am not using the pointers and structures properly could someone help show me what I am doing wrong? Thanks, Quentin // main.c // MacSniffer // #include <pcap.h> #include <string.h> #include <stdlib.h> #define MAXBYTES2CAPTURE 65535 #ifdef WORDS_BIGENDIAN typedef struct frame_control { unsigned int subtype:4; /*frame subtype field*/ unsigned int protoVer:2; /*frame type field*/ unsigned int version:2; /*protocol version*/ unsigned int order:1; unsigned int protected:1; unsigned int moreDate:1; unsigned int power_management:1; unsigned int retry:1; unsigned int moreFrag:1; unsigned int fromDS:1; unsigned int toDS:1; }frame_control; struct ieee80211_radiotap_header{ u_int8_t it_version; u_int8_t it_pad; u_int16_t it_len; u_int32_t it_present; u_int64_t MAC_timestamp; u_int8_t flags; u_int8_t dataRate; u_int16_t channelfrequency; u_int16_t channFreq_pad; u_int16_t channelType; u_int16_t channType_pad; u_int8_t ssiSignal; u_int8_t ssiNoise; u_int8_t antenna; }; #else typedef struct frame_control { unsigned int protoVer:2; /* protocol version*/ unsigned int type:2; /*frame type field (Management,Control,Data)*/ unsigned int subtype:4; /* frame subtype*/ unsigned int toDS:1; /* frame coming from Distribution system */ unsigned int fromDS:1; /*frame coming from Distribution system */ unsigned int moreFrag:1; /* More fragments?*/ unsigned int retry:1; /*was this frame retransmitted*/ unsigned int powMgt:1; /*Power Management*/ unsigned int moreDate:1; /*More Date*/ unsigned int protectedData:1; /*Protected Data*/ unsigned int order:1; /*Order*/ }frame_control; struct ieee80211_radiotap_header{ u_int8_t it_version; u_int8_t it_pad; u_int16_t it_len; u_int32_t it_present; u_int64_t MAC_timestamp; u_int8_t flags; u_int8_t dataRate; u_int16_t channelfrequency; u_int16_t channelType; int ssiSignal:8; int ssiNoise:8; }; #endif struct wi_frame { u_int16_t fc; u_int16_t wi_duration; u_int8_t wi_add1[6]; u_int8_t wi_add2[6]; u_int8_t wi_add3[6]; u_int16_t wi_sequenceControl; // u_int8_t wi_add4[6]; //unsigned int qosControl:2; //unsigned int frameBody[23124]; }; void processPacket(u_char *arg, const struct pcap_pkthdr* pkthdr, const u_char* packet) { int i= 0, *counter = (int *) arg; struct ieee80211_radiotap_header *rh =(struct ieee80211_radiotap_header *)packet; struct wi_frame *fr= (struct wi_frame *)(packet + rh->it_len); u_char *ptr; //printf("Frame Type: %d",fr->wi_fC->type); printf("Packet count: %d\n", ++(*counter)); printf("Received Packet Size: %d\n", pkthdr->len); if(rh->it_version != NULL) { printf("Radiotap Version: %d\n",rh->it_version); } if(rh->it_pad!=NULL) { printf("Radiotap Pad: %d\n",rh->it_pad); } if(rh->it_len != NULL) { printf("Radiotap Length: %d\n",rh->it_len); } if(rh->it_present != NULL) { printf("Radiotap Present: %c\n",rh->it_present); } if(rh->MAC_timestamp != NULL) { printf("Radiotap Timestamp: %u\n",rh->MAC_timestamp); } if(rh->dataRate != NULL) { printf("Radiotap Data Rate: %u\n",rh->dataRate); } if(rh->channelfrequency != NULL) { printf("Radiotap Channel Freq: %u\n",rh->channelfrequency); } if(rh->channelType != NULL) { printf("Radiotap Channel Type: %06x\n",rh->channelType); } if(rh->ssiSignal != NULL) { printf("Radiotap SSI signal: %d\n",rh->ssiSignal); } if(rh->ssiNoise != NULL) { printf("Radiotap SSI Noise: %d\n",rh->ssiNoise); } ptr = fr->wi_add1; int k= 6; printf("Destination Address:"); do{ printf("%s%X",(k==6)?" ":":",*ptr++); } while(--k>0); printf("\n"); ptr = fr->wi_add2; k=0; printf("Source Address:"); do{ printf("%s%X",(k==6)?" ":":",*ptr++); }while(--k>0); printf("\n"); ptr = fr->wi_add3; k=0; do{ printf("%s%X",(k==6)?" ":":",*ptr++); } while(--k>0); printf("\n"); /* for(int j = 0; j < 23124;j++) { if(fr->frameBody[j]!= NULL) { printf("%x",fr->frameBody[j]); } } */ for (i = 0;i<pkthdr->len;i++) { if(isprint(packet[i +rh->it_len])) { printf("%c",packet[i + rh->it_len]); } else{printf(".");} //print newline after each section of the packet if((i%16 ==0 && i!=0) ||(i==pkthdr->len-1)) { printf("\n"); } } return; } int main(int argc, char** argv) { int count = 0; pcap_t* descr = NULL; char errbuf[PCAP_ERRBUF_SIZE], *device = NULL; struct bpf_program fp; char filter[]="wlan broadcast"; const u_char* packet; memset(errbuf,0,PCAP_ERRBUF_SIZE); device = argv[1]; if(device == NULL) { fprintf(stdout,"Supply a device name "); } descr = pcap_create(device,errbuf); pcap_set_rfmon(descr,1); pcap_set_promisc(descr,1); pcap_set_snaplen(descr,30); pcap_set_timeout(descr,10000); pcap_activate(descr); int dl =pcap_datalink(descr); printf("The Data Link type is %s",pcap_datalink_val_to_name(dl)); //pcap_dispatch(descr,MAXBYTES2CAPTURE,1,512,errbuf); //Open device in promiscuous mode //descr = pcap_open_live(device,MAXBYTES2CAPTURE,1,512,errbuf); /* if(pcap_compile(descr,&fp,filter,0,PCAP_NETMASK_UNKNOWN)==-1) { fprintf(stderr,"Error compiling filter\n"); exit(1); } if(pcap_setfilter(descr,&fp)==-1) { fprintf(stderr,"Error setting filter\n"); exit(1); } */ pcap_loop(descr,0, processPacket, (u_char *) &count); return 0; }

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  • SIGSEGV problem

    - by sickmate
    I'm designing a protocol (in C) to implement the layered OSI network structure, using cnet (http://www.csse.uwa.edu.au/cnet/). I'm getting a SIGSEGV error at runtime, however cnet compiles my source code files itself (I can't compile it through gcc) so I can't easily use any debugging tools such as gdb to find the error. Here's the structures used, and the code in question: typedef struct { char *data; } DATA; typedef struct { CnetAddr src_addr; CnetAddr dest_addr; PACKET_TYPE type; DATA data; } Packet; typedef struct { int length; int checksum; Packet datagram; } Frame; static void keyboard(CnetEvent ev, CnetTimerID timer, CnetData data) { char line[80]; int length; length = sizeof(line); CHECK(CNET_read_keyboard((void *)line, (unsigned int *)&length)); // Reads input from keyboard if(length > 1) { /* not just a blank line */ printf("\tsending %d bytes - \"%s\"\n", length, line); application_downto_transport(1, line, &length); } } void application_downto_transport(int link, char *msg, int *length) { transport_downto_network(link, msg, length); } void transport_downto_network(int link, char *msg, int *length) { Packet *p; DATA *d; p = (Packet *)malloc(sizeof(Packet)); d = (DATA *)malloc(sizeof(DATA)); d->data = msg; p->data = *d; network_downto_datalink(link, (void *)p, length); } void network_downto_datalink(int link, Packet *p, int *length) { Frame *f; // Encapsulate datagram and checksum into a Frame. f = (Frame *)malloc(sizeof(Frame)); f->checksum = CNET_crc32((unsigned char *)(p->data).data, *length); // Generate 32-bit CRC for the data. f->datagram = *p; f->length = sizeof(f); //Pass Frame to the CNET physical layer to send Frame to the require link. CHECK(CNET_write_physical(link, (void *)f, (size_t *)f->length)); free(p->data); free(p); free(f); } I managed to find that the line: CHECK(CNET_write_physical(link, (void *)f, (size_t *)f-length)); is causing the segfault but I can't work out why. Any help is greatly appreciated.

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  • paket drop and splits in udp tunnel

    - by sr-dusad
    hi guys ! Currently I am working on video conferencing project.For this i m using pwnat for nat traversing. pwnat is based on udp tunneling.I m using the TCP connection for data transmission. My problem is that when i send a packet , it does not reach properly at its destination side . Sometime it drops the packet and many times it breaks ( split ) the packet into pieces. Please Help me .. How can i send and recieve a packet into single piece. So, i can draw image properly and play sound. Any kind of help will be appriciated . Thanks in advance

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  • TCP sequence number question

    - by Meta
    This is more of a theoretical question than an actual problem I have. If I understand correctly, the sequence number in the TCP header of a packet is the index of the first byte in the packet in the whole stream, correct? If that is the case, since the sequence number is an unsigned 32-bit integer, then what happens after more than FFFFFFFF = 4294967295 bytes are transferred? Will the sequence number wrap around, or will the sender send a SYN packet to restart at 0?

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