38 skills found · Page 1 of 2
ddddddO / PackemonPacket monster (っ‘-’)╮=͟͟͞͞◒ ヽ( '-'ヽ) TUI tool for sending packets of arbitrary input and monitoring packets on any network interfaces (default: eth0). Windows/macOS/Linux
egnor / Wt32 Eth01Bits and bobs related to Wireless-Tag's WT32-ETH01 board
ldijkman / WT32 ETH01 LAN 8720 RJ45 WT32-ETH01 LAN 8720 RJ45 wired Wireless-tag
widora / U Boot Mt7688uboot for mt76x8,Default console:115200,8,n,1,UART0,The web on ETH0
khoih-prog / WebServer WT32 ETH01Simple Ethernet WebServer, HTTP/HTTPS Client wrapper library for WT32_ETH01 boards using LAN8720 Ethernet. The WebServer supports HTTP(S) GET and POST requests, provides argument parsing, handles one client at a time. It provides HTTP(S), MQTT(S) Client and supports WebServer serving from LittleFS/SPIFFS. Now supporting ESP32 core v2.0.0+
cslev / Find Veth DockerSimple script to find out which veth interface on the host corresponds to the eth0 interface of a container
zuidwijk / Slimmelezer Wt32 Eth01No description available
SOYJUN / Application With Raw IP SocketsOverview For this assignment you will be developing an application that uses raw IP sockets to ‘walk’ around an ordered list of nodes (given as a command line argument at the ‘source’ node, which is the node at which the tour was initiated), in a manner similar to the IP SSRR (Strict Source and Record Route) option. At each node, the application pings the preceding node in the tour. However, unlike the ping code in Stevens, you will be sending the ping ICMP echo request messages through a SOCK_RAW-type PF_PACKET socket and implementing ARP functionality to find the Ethernet address of the target node. Finally, when the ‘walk’ is completed, the group of nodes visited on the tour will exchange multicast messages. Your code will consist of two process modules, a ‘Tour’ application module (which will implement all the functionality outlined above, except for ARP activity) and an ARP module. The following should prove to be useful reference material for the assignment: Sections 21.2, 21.3, 21.6 and 21.10, Chapter 21, on Multicasting. Sections 27.1 to 27.3, Chapter 27, on the IP SSRR option. Sections 28.1 to 28.5, Chapter 28, on raw sockets, the IP_HDRINCL socket option, and ping. Sections 15.5, Chapter 15, on Unix domain SOCK_STREAM sockets. Figure 29.14, p. 807, and the corresponding explanation on p. 806, on filling in an IP header when the IP_HDRINCL socket option is in effect. The Lecture Slides on ARP & RARP (especially Section 4.4, ARP Packet Format, and the Figure 4.3 it includes). The link http://www.pdbuchan.com/rawsock/rawsock.html contains useful code samples that use IP raw sockets and PF_PACKET sockets. Note, in partcular, the code “icmp4_ll.c” in Table 2 for building an echo request sent through a PF_PACKET SOCK_RAW socket. The VMware environment You will be using the same vm1 , . . . . . , vm10 nodes you used for Assignment 3. However, unlike Assignment 3, you should use only interfaces eth0 and their associated IP addresses and ignore the other Ethernet interfaces that nodes have (interfaces eth0 make vm1 , . . . . . , vm10 look as if they belong to the same Ethernet LAN segment IP network 130.245.156.0/24). Note that, apart from the primary IP addresses associated with interfaces eth0, some nodes might also have one or more alias IP addresses associated with their interface eth0. Tour application module specifications The application will create a total of four sockets: two IP raw sockets, a PF_PACKET socket and a UDP socket for multicasting. We shall call the two IP raw sockets the ‘rt ’ (‘route traversal’) and ‘pg ’ (‘ping’) sockets, respectively. The rt socket should have the IP_HDRINCL option set. You will only be receiving ICMP echo reply messages through the pg socket (and not sending echo requests), so it does not matter whether it has the IP_HDRINCL option set or not. The pg socket should have protocol value (i.e., protocol demultiplexing key in the IP header) IPPROTO_ICMP. The rt socket should have a protocol value that identifies the application - i.e., some value other than the IPPROTO_XXXX values in /usr/include/netinet/in.h. However, remember that you will all be running your code using the same root account on the vm1 , . . . . . , vm10 nodes. So if two of you happen to choose the same protocol value and happen to be running on the same vm node at the same time, your applications will receive each other’s IP packets. For that reason, try to choose a protocol value for your rt socket that is likely to be unique to yourself. The PF_PACKET socket should be of type SOCK_RAW (not SOCK_DGRAM). This socket should have a protocol value of ETH_P_IP = 0x0800 (IPv4). The UDP socket for multicasting will be discussed below. Note that, depending on how you choose to bind that socket, you might actually need to have two UDP sockets for multicast communication – see bottom of p. 576, Section 21.10. Your application will, of course, have to be running on every vm node that is included in the tour. When evoking the application on the source node, the user supplies a sequence of vm node names (not IP addresses) to be visited in order. This command line sequence starts with the next node to be visited from the source node (i.e., it does not start with the source node itself). The sequence can include any number of repeated visits to the same node. For example, suppose that the source node is vm3 and the executable is called badr_tour : [root@vm3/root]# badr_tour vm2 vm10 vm4 vm7 vm5 vm2 vm6 vm2 vm9 vm4 vm7 vm2 vm6 vm5 vm1 vm10 vm8 (but note that the tour does not necessarily have to visit every vm node; and the same node should not appear consequentively in the tour list – i.e., the next node on the tour cannot be the current node itself). The application turns the sequence into a list of IP addresses for source routing. It also adds the IP address of the source node itself to the beginning of the list. The list thus produced will be carried as the payload of an IP packet, not as a SSRR option in the packet header. It is our application which will ensure that every node in the sequence is visited in order, not the IP SSRR capability. The source node should also add to the list an IP multicast address and a port number of its choice. It should also join the multicast group at that address and port number on its UDP socket. The TTL for outgoing multicasts should be set to 1. The application then fills in the header of an IP packet, designating itself as the IP source, and the next node to be visited as the IP destination. The packet is sent out on the rt socket. Note that on Linux, all the fields of the packet header must be in network byte order (Stevens, Section 28.3, p. 737, the fourth bullet point). When filling in the packet header, you should explicitly fill in the identification field (recall that, with the IP_HDRINCL socket option, if the identification field is given value 0, then the kernel will set its value). Try to make sure that the value you choose is likely to be unique to yourself (for reasons similar to those explained with respect to the IPPROTO_XXXX in 1. above). When a node receives an IP packet on its rt socket, it should first check that the identification field carries the right value (this implies that you will hard code your choice of identification field value determined in item 2 above in your code). If the identification field value does not check out, the packet is ignored. For a valid packet : Print out a message along the lines of: <time> received source routing packet from <hostname> <time> is the current time in human-readable format (see lines 19 & 20 in Figure 1.9, p. 14, and the corresponding explanation on p. 14f.), and <hostname> is the host name corresponding to the source IP address in the header of the received packet. If this is the first time the node is visited, the application should use the multicast address and port number in the packet received to join the multicast group on its UDP socket. The TTL for outgoing multicasts should be set to 1. The application updates the list in the payload, so that the next node in the tour can easily identify what the next hop from itself will be when it receives the packet. How you do this I leave up to you. You could, for example, include as part of the payload a pointer field into the list of nodes to be visited. This pointer would then be updated to the next entry in the list as the packet progresses hop by hop (see Figure 27.1 and the associated explanation on pp. 711-712). Other solutions are, of course, possible. The application then fills in a new IP header, designating itself as the IP source, and the next node to be visited as the IP destination. The identification field should be set to the same value as in the received packet. The packet is sent out on the rt socket. The node should also initiate pinging to the preceding node in the tour (the IP address of which it should pick up from the header of the received packet). However, unlike the Stevens ping code, it will be using the SOCK_RAW-type PF_PACKET socket of item 1 above to send the ICMP echo request messages. Before it can send echo request messages, the application has to call on the ARP module you will implement to get the Ethernet address of this preceding / ‘target’ node; this call is made using the API function areq which you will also implement (see sections ARP module specifications & API specifications below). Note that ARP has to be evoked every time the application wants to send out an echo request message, and not just the first time. An echo request message has to be encapsulated in a properly-formulated IP packet, which is in turn encapsulated in a properly-formulated Ethernet frame transmitted out through the PF_PACKET socket ; otherwise, ICMP at the source node will not receive it. You will have to modify Stevens’ ping code accordingly, specifically, the send_v4 function. In particular, the Ethernet frame must have a value of ETH_P_IP = 0x0800 (IPv4 – see <linux/if_ether.h>) in the frame type / ‘length’ field ; and the encapsulated IP packet must have a value of IPPROTO_ICMP = 0x01 (ICMPv4 – see <netinet_in.h>) in its protocol field. You should also simplify the ping code in its entirety by stripping all the ‘indirection’ IPv4 / IPv6 dual-operability paraphernalia and making the code work just for IPv4. Also note that the functions host_serv and freeaddrinfo, together with the associated structure addrinfo (see Sections 11.6, 11.8 & 11.11), in Figures 27.3, 27.6 & 28.5 ( pp. 713, 716 & 744f., respectively) can be replaced by the function gethostbyname and associated structure hostent (see Section 11.3) where needed. Also, there is no ‘-v’ verbose option, so this too should be stripped from Stevens’ code. When a node is ready to start pinging, it first prints out a ‘PING’ message similar to lines 32-33 of Figure 28.5, p. 744. It then builds up ICMP echo request messages and sends them to the source node every 1 second through the PF_PACKET socket. It also reads incoming echo response messages off the pg socket, in response to which it prints out the same kind of output as the code of Figure 28.8, p. 748. If this node and its preceding node have been previously visited in that order during the tour, then pinging would have already been initiated from the one to the other in response to the first visit, and nothing further should nor need be done during second and subsequent visits. In light of the above, note that once a node initiates pinging, it needs to read from both its rt and pg sockets, necessitating the use of the select function. As will be clear from what follows below, the application will anyway be needing also to simultaneously monitor its UDP socket for incoming multicast datagrams. When the last node on the tour is reached, and if this is the first time it is visited, it joins the multicast group and starts pinging the preceding node (if it is not already doing so). After a few echo replies are received (five, say), it sends out the multicast message below on its UDP socket (i.e., the node should wait about five seconds before sending the multicast message) : <<<<< This is node vmi . Tour has ended . Group members please identify yourselves. >>>>> where vmi is the name (not IP address) of the node. The node should also print this message out on stdout preceded, on the same line, by the phrase: Node vmi . Sending: <then print out the message sent>. Each node vmj receiving this message should print out the message received preceded, on the same line, by the phrase: Node vmj . Received <then print out the message received>. Each such node in step a above should then immediately stop its pinging activity. The node should then send out the following multicast message: <<<<< Node vmj . I am a member of the group. >>>>> and print out this message preceded, on the same line, by the phrase: Node vmj . Sending: <then print out the message sent>. Each node receiving these second multicast messages (i.e., the messages that nodes – including itself – sent out in step c above) should print each such message out preceded, on the same line, by the phrase: Node vmk . Received: <then print out the message received>. Reading from the socket in step d above should be implemented with a 5-second timeout. When the timeout expires, the node should print out another message to the effect that it is terminating the Tour application, and gracefully exit its Tour process. Note that under Multicast specifications, the last node in the tour, which sends out the End of Tour message, should itself receive a copy of that message and, when it does, it should behave exactly as do the other nodes in steps a. – e. above. ARP module specifications Your executable is evoked with no command line arguments. Like the Tour module, it will be running on every vm node. It uses the get_hw_addrs function of Assignment 3 to explore its node’s interfaces and build a set of <IP address , HW address> matching pairs for all eth0 interface IP addresses (including alias IP addresses, if any). Write out to stdout in some appropriately clear format the address pairs found. The module creates two sockets: a PF_PACKET socket and a Unix domain socket. The PF_PACKET should be of type SOCK_RAW (not type SOCK_DGRAM) with a protocol value of your choice (but not one of the standard values defined in <linux/if_ether.h>) which is, hopefully, unique to yourself. This value effectively becomes the protocol value for your implementation of ARP. Because this protocol value will be carried in the frame type / ‘length’ field of the Ethernet frame header (see Figure 4.3 of the ARP & RARP handout), the value chosen should be not less than 1536 (0x600) so that it is not misinterpreted as the length of an Ethernet 802.3 frame. The Unix domain socket should be of type SOCK_STREAM (not SOCK_DGRAM). It is a listening socket bound to a ‘well-known’ sun_path file. This socket will be used to communicate with the function areq that is implemented in the Tour module (see the section API specifications below). In this context, areq will act as the client and the ARP module as the server. The ARP module then sits in an infinite loop, monitoring these two sockets. As ARP request messages arrive on the PF_PACKET socket, the module processes them, and responds with ARP reply messages as appropriate. The protocol builds a ‘cache’ of matching <IP address , HW address> pairs from the replies (and requests – see below) it receives. For simplicity, and unlike the real ARP, we shall not implement timing out mechanisms for these cache entries. A cache entry has five parts: (i) IP address ; (ii) HW address ; (iii) sll_ifindex (the interface to be used for reaching the matching pair <(i) , (ii)>) ; (iv) sll_hatype ; and (v) a Unix-domain connection-socket descriptor for a connected client (see the section API specifications below for the latter three). When an ARP reply is being entered in the cache, the ARP module uses the socket descriptor in (v) to send a reply to the client, closes the connection socket, and deletes the socket descriptor from the cache entry. Note that, like the real ARP, when an ARP request is received by a node, and if the request pertains to that receiving node, the sender’s (see Figure 4.3 of the ARP & RARP handout) <IP address, HW address> matching pair should be entered into the cache if it is not already there (together, of course, with (iii) sll_ifindex & (iv) sll_hatype), or updated if need be if such an entry already exists in the cache. If the ARP request received does not pertain to the node receiving it, but there is already an entry in that receiving node's cache for the sender’s <IP address, HW address> matching pair, that entry should be checked and updated if need be. If there is no such entry, no action is taken (in particular, and unlike the case above, no new entry should be made in the receiving node's cache of the sender’s <IP address, HW address> matching pair if such an entry does not already exist). ARP request and reply messages have the same format as Figure 4.3 of the ARP & RARP handout, but with an extra 2-byte identification field added at the beginning which you fill with a value chosen so that it has a high probability of being unique to yourself. This value is to be echoed in the reply message, and helps to act as a further filter in case some other student happens to have fortuitously chosen the same value as yourself for the protocol parameter of the ARP PF_PACKET. Values in the fields of our ARP messages must be in network byte order. You might find the system header file <linux/if_arp.h> useful for manipulating ARP request and reply messages, but remember that our version of these messages have an extra two-byte field as mentioned above. Your code should print out on stdout, in some appropriately clear format, the contents of the Ethernet frame header and ARP request message you send. As described in Section 4.4 of the ARP & RARP handout, the node that responds to the request should, in its reply message, swap the two sender addresses with the two target addresses, as well as, of course, echo back the extra identification field sent with the request. The protocol at this responding node should print out, in an appropriately clear format, both the request frame (header and ARP message) it receives and the reply frame it sends. Similarly, the node that sent the request should print out the reply frame it receives. Finally, recall that the node issuing the request sends out a broadcast Ethernet frame, but the responding node replies with a unicast frame. API specifications The API is for communication between the Tour process and the ARP process. It consists of a single function, areq, implemented in the Tour module. areq is called by send_v4 function of the application every time the latter want to send out an ICMP echo request message: int areq (struct sockaddr *IPaddr, socklen_t sockaddrlen, struct hwaddr *HWaddr); IPaddr contains the primary or alias IPaddress of a ‘target’ node on the LAN for which the corresponding hardware address is being requested. hwaddr is a new structure (and not a pre-existing type) modeled on the sockaddr_ll of PF_PACKET; you will have to declare it in your code. It is used to return the requested hardware address to the caller of areq : structure hwaddr { int sll_ifindex; /* Interface number */ unsigned short sll_hatype; /* Hardware type */ unsigned char sll_halen; /* Length of address */ unsigned char sll_addr[8]; /* Physical layer address */ }; areq creates a Unix domain socket of type SOCK_STREAM and connects to the ‘well-known’ sun_path file of the ARP listening socket. It sends the IP address from parameter IPaddr and the information in the three fields of parameter HWaddr to ARP. It then blocks on a read awaiting a reply from ARP. This read should be backed up by a timeout since it is possible that no reply is received for the request. If a timeout occurs, areq should close the socket and return to its caller indicating failure (through its int return value). Your application code should print out on stdout, in some appropriately clear format, a notification every time areq is called, giving the IP address for which a HW address is being sought. It should similarly print out the result when the call to areq returns (HW address returned, or failure). When the ARP module receives a request for a HW address from areq through its Unix domain listening socket, it first checks if the required HW address is already in the cache. If so, it can respond immediately to the areq and close the Unix domain connection socket. Else : it makes an ‘incomplete’ entry in the cache, consisting of parts (i), (iii), (iv) and (v) ; puts out an ARP request message on the network on its PF_PACKET socket; and starts monitoring the areq connection socket for readability – if the areq client closes the connection socket (this would occur in response to a timeout in areq), ARP deletes the corresponding incomplete entry from the cache (and ignores any subsequent ARP reply from the network if such is received). On the other hand, if ARP receives a reply from the network, it updates the incomplete cache entry, responds to areq, and closes the connection socket.
thryvos / Tasmota WT32 ETH01Guide to flash Tasmota firmware into WT32-ETH01
mayfrost / NCMatrixNCMatrix is a modified version of the CMatrix screen saver with the added functionality of network traffic monitoring. Example usage: ncmatrix -s -b -u 10 -I eth0 -T red -R magenta
SmileShow-DH / Linux 查看软件xxx安装内容 #dpkg -L xxx 查找软件 #apt-cache search 正则表达式 查找文件属于哪个包 #dpkg -S filename apt-file search filename 查询软件xxx依赖哪些包 #apt-cache depends xxx 查询软件xxx被哪些包依赖 #apt-cache rdepends xxx 增加一个光盘源 #sudo apt-cdrom add 系统升级 #sudo apt-get update #sudo apt-get upgrade #sudo apt-get dist-upgrade 清除所以删除包的残余配置文件 #dpkg -l |grep ^rc|awk ‘{print $2}’ |tr [”"n”] [” “]|sudo xargs dpkg -P - 编译时缺少h文件的自动处理 #sudo auto-apt run ./configure 查看安装软件时下载包的临时存放目录 #ls /var/cache/apt/archives 备份当前系统安装的所有包的列表 #dpkg –get-selections | grep -v deinstall > ~/somefile 从上面备份的安装包的列表文件恢复所有包 #dpkg –set-selections < ~/somefile sudo dselect 清理旧版本的软件缓存 #sudo apt-get autoclean 清理所有软件缓存 #sudo apt-get clean 删除系统不再使用的孤立软件 #sudo apt-get autoremove 查看包在服务器上面的地址 #apt-get -qq –print-uris install ssh | cut -d"’ -f2 ------------------------------------------------系统------------------------------------------------ 查看内核 #uname -a 查看Ubuntu版本 #cat /etc/issue 查看内核加载的模块 #lsmod 查看PCI设备 #lspci 查看USB设备 #lsusb 查看网卡状态 #sudo ethtool eth0 查看CPU信息 #cat /proc/cpuinfo 显示当前硬件信息 #lshw ------------------------------------------------硬盘------------------------------------------------ 查看硬盘的分区 #sudo fdisk -l 查看IDE硬盘信息 #sudo hdparm -i /dev/hda 查看STAT硬盘信息 #sudo hdparm -I /dev/sda 或 #sudo apt-get install blktool #sudo blktool /dev/sda id 查看硬盘剩余空间 #df -h #df -H 查看目录占用空间 #du -hs 目录名 优盘没法卸载 #sync fuser -km /media/usbdisk ------------------------------------------------内存------------------------------------------------ 查看当前的内存使用情况 #free -m 进程查看当前有哪些进程 #ps -A 中止一个进程 #kill 进程号(就是ps -A中的第一列的数字) 或者 killall 进程名 强制中止一个进程(在上面进程中止不成功的时候使用) #kill -9 进程号 或者 killall -9 进程名 图形方式中止一个程序 #xkill 出现骷髅标志的鼠标，点击需要中止的程序即可 查看当前进程的实时状况 #top 查看进程打开的文件 #lsof -p ADSL 配置 ADSL #sudo pppoeconf ADSL手工拨号 #sudo pon dsl-provider 激活 ADSL #sudo /etc/ppp/pppoe_on_boot 断开 ADSL #sudo poff 查看拨号日志 #sudo plog 如何设置动态域名 #首先去http://www.3322.org申请一个动态域名 #然后修改 /etc/ppp/ip-up 增加拨号时更新域名指令 sudo vim /etc/ppp/ip-up #在最后增加如下行 w3m -no-cookie -dump ------------------------------------------------网络------------------------------------------------ 根据IP查网卡地址 #arping IP地址 查看当前IP地址 #ifconfig eth0 |awk ‘/inet/ {split($2,x,”:”);print x[2]}’ 查看当前外网的IP地址 #w3m -no-cookie -dumpwww.edu.cn|grep-o‘[0-9]"{1,3"}".[0-9]"{1,3"}".[0-9]"{1,3"}".[0-9]"{1,3"}’ #w3m -no-cookie -dumpwww.xju.edu.cn|grep-o’[0-9]"{1,3"}".[0-9]"{1,3"}".[0-9]"{1,3"}".[0-9]"{1,3"}’ #w3m -no-cookie -dump ip.loveroot.com|grep -o’[0-9]"{1,3"}".[0-9]"{1,3"}".[0-9]"{1,3"}".[0-9]"{1,3"}’ 查看当前监听80端口的程序 #lsof -i :80 查看当前网卡的物理地址 #arp -a | awk ‘{print $4}’ ifconfig eth0 | head -1 | awk ‘{print $5}’ 立即让网络支持nat #sudo echo 1 > /proc/sys/net/ipv4/ip_forward #sudo iptables -t nat -I POSTROUTING -j MASQUERADE 查看路由信息 #netstat -rn sudo route -n 手工增加删除一条路由 #sudo route add -net 192.168.0.0 netmask 255.255.255.0 gw 172.16.0.1 #sudo route del -net 192.168.0.0 netmask 255.255.255.0 gw 172.16.0.1 修改网卡MAC地址的方法 #sudo ifconfig eth0 down 关闭网卡 #sudo ifconfig eth0 hw ether 00:AA:BB:CC:DD:EE 然后改地址 #sudo ifconfig eth0 up 然后启动网卡 统计当前IP连接的个数 #netstat -na|grep ESTABLISHED|awk ‘{print $5}’|awk -F: ‘{print $1}’|sort|uniq -c|sort -r -n #netstat -na|grep SYN|awk ‘{print $5}’|awk -F: ‘{print $1}’|sort|uniq -c|sort -r -n 统计当前20000个IP包中大于100个IP包的IP地址 #tcpdump -tnn -c 20000 -i eth0 | awk -F “.” ‘{print $1″.”$2″.”$3″.”$4}’ | sort | uniq -c | sort -nr | awk ‘ $1 > 100 ‘ 屏蔽IPV6 #echo “blacklist ipv6″ | sudo tee /etc/modprobe.d/blacklist-ipv6 ------------------------------------------------服务------------------------------------------------ 添加一个服务 #sudo update-rc.d 服务名 defaults 99 删除一个服务 #sudo update-rc.d 服务名 remove 临时重启一个服务 #/etc/init.d/服务名 restart 临时关闭一个服务 #/etc/init.d/服务名 stop 临时启动一个服务 #/etc/init.d/服务名 start ------------------------------------------------设置------------------------------------------------ 配置默认Java使用哪个 #sudo update-alternatives –config java 修改用户资料 #sudo chfn userid 给apt设置代理 #export http_proxy=http://xx.xx.xx.xx:xxx 修改系统登录信息 #sudo vim /etc/motd ------------------------------------------------中文------------------------------------------------ 转换文件名由GBK为UTF8 #sudo apt-get install convmv convmv -r -f cp936 -t utf8 –notest –nosmart * 批量转换src目录下的所有文件内容由GBK到UTF8 #find src -type d -exec mkdir -p utf8/{} "; find src -type f -exec iconv -f GBK -t UTF-8 {} -o utf8/{} "; mv utf8/* src rm -fr utf8 转换文件内容由GBK到UTF8 #iconv -f gbk -t utf8 $i > newfile 转换 mp3 标签编码 #sudo apt-get install python-mutagen find . -iname “*.mp3” -execdir mid3iconv -e GBK {} "; 控制台下显示中文 #sudo apt-get install zhcon 使用时，输入zhcon即可 ------------------------------------------------文件------------------------------------------------ 快速查找某个文件 #whereis filename #find 目录 -name 文件名 查看文件类型 #file filename 显示xxx文件倒数6行的内容 #tail -n 6 xxx 让tail不停地读地最新的内容 #tail -n 10 -f /var/log/apache2/access.log 查看文件中间的第五行（含）到第10行（含）的内容 #sed -n ‘5,10p’ /var/log/apache2/access.log 查找包含xxx字符串的文件 #grep -l -r xxx . 全盘搜索文件(桌面可视化) gnome-search-tool 查找关于xxx的命令 #apropos xxx man -k xxx 通过ssh传输文件 #scp -rp /path/filenameusername@remoteIP:/path #将本地文件拷贝到服务器上 #scp -rpusername@remoteIP:/path/filename/path #将远程文件从服务器下载到本地 查看某个文件被哪些应用程序读写 #lsof 文件名 把所有文件的后辍由rm改为rmvb #rename ’s/.rm$/.rmvb/’ * 把所有文件名中的大写改为小写 #rename ‘tr/A-Z/a-z/’ * 删除特殊文件名的文件，如文件名：–help.txt #rm — –help.txt 或者 rm ./–help.txt 查看当前目录的子目录 #ls -d */. 或 echo */. 将当前目录下最近30天访问过的文件移动到上级back目录 #find . -type f -atime -30 -exec mv {} ../back "; 将当前目录下最近2小时到8小时之内的文件显示出来 #find . -mmin +120 -mmin -480 -exec more {} "; 删除修改时间在30天之前的所有文件 #find . -type f -mtime +30 -mtime -3600 -exec rm {} "; 查找guest用户的以avi或者rm结尾的文件并删除掉 #find . -name ‘*.avi’ -o -name ‘*.rm’ -user ‘guest’ -exec rm {} "; 查找的不以java和xml结尾,并7天没有使用的文件删除掉 #find . ! -name *.java ! -name ‘*.xml’ -atime +7 -exec rm {} "; 统计当前文件个数 #ls /usr/bin|wc -w 统计当前目录个数 #ls -l /usr/bin|grep ^d|wc -l 显示当前目录下2006-01-01的文件名 #ls -l |grep 2006-01-01 |awk ‘{print $8}’ ------------------------------------------------FTP------------------------------------------------ 上传下载文件工具-filezilla #sudo apt-get install filezilla filezilla无法列出中文目录？ 站点->字符集->自定义->输入：GBK 本地中文界面 1）下载filezilla中文包到本地目录，如~/ 2）#unrar x Filezilla3_zhCN.rar 3) 如果你没有unrar的话，请先安装rar和unrar #sudo apt-get install rar unrar #sudo ln -f /usr/bin/rar /usr/bin/unrar 4）先备份原来的语言包,再安装；实际就是拷贝一个语言包。 #sudo cp /usr/share/locale/zh_CN/filezilla.mo /usr/share/locale/zh_CN/filezilla.mo.bak #sudo cp ~/locale/zh_CN/filezilla.mo /usr/share/locale/zh_CN/filezilla.mo 5）重启filezilla,即可！ --------------------------------------解压缩--------------------------------------------- 解压缩 xxx.tar.gz #tar -zxvf xxx.tar.gz 解压缩 xxx.tar.bz2 #tar -jxvf xxx.tar.bz2 压缩aaa bbb目录为xxx.tar.gz #tar -zcvf xxx.tar.gz aaa bbb 压缩aaa bbb目录为xxx.tar.bz2 #tar -jcvf xxx.tar.bz2 aaa bbb 解压缩 RAR 文件 1) 先安装 #sudo apt-get install rar unrar #sudo ln -f /usr/bin/rar /usr/bin/unrar 2) 解压 #unrar x aaaa.rar 解压缩 ZIP 文件 1) 先安装 #sudo apt-get install zip unzip #sudo ln -f /usr/bin/zip /usr/bin/unzip 2) 解压 #unzip x aaaa.zip Nautilus 显示隐藏文件 Ctrl+h 显示地址栏 Ctrl+l 特殊 URI 地址 * computer:/// - 全部挂载的设备和网络 * network:/// - 浏览可用的网络 * burn:/// - 一个刻录 CDs/DVDs 的数据虚拟目录 * smb:/// - 可用的 windows/samba 网络资源 * x-nautilus-desktop:/// - 桌面项目和图标 *file:///- 本地文件 * trash:/// - 本地回收站目录 * ftp:// - FTP 文件夹 * ssh:// - SSH 文件夹 * fonts:/// - 字体文件夹，可将字体文件拖到此处以完成安装 * themes:/// - 系统主题文件夹 查看已安装字体 在nautilus的地址栏里输入”fonts:///“，就可以查看本机所有的fonts --------------------------------------程序 -------------------------------------- 详细显示程序的运行信息 #strace -f -F -o outfile 日期和时间 设置日期 #date -s mm/dd/yy 设置时间 #date -s HH:MM 将时间写入CMOS #hwclock –systohc 读取CMOS时间 #hwclock –hctosys 从服务器上同步时间 #sudo ntpdate time.nist.gov #sudo ntpdate time.windows.com 控制台 不同控制台间切换 Ctrl + ALT + ← Ctrl + ALT + → 指定控制台切换 Ctrl + ALT + Fn(n:1~7) 控制台下滚屏 SHIFT + pageUp/pageDown 控制台抓图 #setterm -dump n(n:1~7) --------------------------------------数据库 -------------------------------------- mysql的数据库存放在地方 #/var/lib/mysql 从mysql中导出和导入数据 #mysqldump 数据库名 > 文件名 #导出数据库 #mysqladmin create 数据库名 #建立数据库 #mysql 数据库名 < 文件名 #导入数据库 忘了mysql的root口令怎么办 #sudo /etc/init.d/mysql stop #sudo mysqld_safe –skip-grant-tables #sudo mysqladmin -u user password ‘newpassword” #sudo mysqladmin flush-privileges 修改mysql的root口令 #sudo mysqladmin -uroot -p password ‘你的新密码’ --------------------------------------其它 -------------------------------------- 下载网站文档 #wget -r -p -np -khttp://www.21cn.com · r：在本机建立服务器端目录结构； · -p: 下载显示HTML文件的所有图片； · -np：只下载目标站点指定目录及其子目录的内容； · -k: 转换非相对链接为相对链接。 如何删除Totem电影播放机的播放历史记录 #rm ~/.recently-used 如何更换gnome程序的快捷键 点击菜单，鼠标停留在某条菜单上，键盘输入任意你所需要的键，可以是组合键，会立即生效； 如果要清除该快捷键，请使用backspace vim 如何显示彩色字符 #sudo cp /usr/share/vim/vimcurrent/vimrc_example.vim /usr/share/vim/vimrc 如何在命令行删除在会话设置的启动程序 #cd ~/.config/autostart rm 需要删除启动程序 如何提高wine的反应速度 #sudo sed -ie ‘/GBK/,/^}/d’ /usr/share/X11/locale/zh_CN.UTF-8/XLC_LOCALE #chgrp [语法]: chgrp [-R] 文件组 文件… [说明]： 文件的GID表示文件的文件组，文件组可用数字表示， 也可用一个有效的组名表示，此命令改变一个文件的GID，可参看chown。 -R 递归地改变所有子目录下所有文件的存取模式 [例子]: ＃chgrp group file 将文件 file 的文件组改为 group #chmod [语法]: chmod [-R] 模式 文件… 或 chmod [ugoa] {+|-|=} [rwxst] 文件… [说明]: 改变文件的存取模式，存取模式可表示为数字或符号串，例如： ＃chmod nnnn file ， n为0-7的数字，意义如下: 4000 运行时可改变UID 2000 运行时可改变GID 1000 置粘着位 0400 文件主可读 0200 文件主可写 0100 文件主可执行 0040 同组用户可读 0020 同组用户可写 0010 同组用户可执行 0004 其他用户可读 0002 其他用户可写 0001 其他用户可执行 nnnn 就是上列数字相加得到的，例如 chmod 0777 file 是指将文件 file 存取权限置为所有用户可读可写可执行。 -R 递归地改变所有子目录下所有文件的存取模式 u 文件主 g 同组用户 o 其他用户 a 所有用户 + 增加后列权限 - 取消后列权限 = 置成后列权限 r 可读 w 可写 x 可执行 s 运行时可置UID t 运行时可置GID [例子]: ＃chmod 0666 file1 file2 将文件 file1 及 file2 置为所有用户可读可写 ＃chmod u+x file 对文件 file 增加文件主可执行权限 ＃chmod o-rwx 对文件file 取消其他用户的所有权限 #chown [语法]: chown [-R] 文件主 文件… [说明]: 文件的UID表示文件的文件主，文件主可用数字表示， 也可用一个有效的用户名表示，此命令改变一个文件的UID，仅当此文件的文件主或超级用户可使用。 -R 递归地改变所有子目录下所有文件的存取模式 [例子]: #chown mary file 将文件 file 的文件主改为 mary #chown 150 file 将文件 file 的UID改为150 Ubuntu命令行下修改网络配置 以eth0为例 1. 以DHCP方式配置网卡 编辑文件/etc/network/interfaces: #sudo vi /etc/network/interfaces 并用下面的行来替换有关eth0的行: # The primary network interface - use DHCP to find our address auto eth0 iface eth0 inet dhcp 用下面的命令使网络设置生效: #sudo /etc/init.d/networking restart 当然,也可以在命令行下直接输入下面的命令来获取地址 #sudo dhclient eth0 2. 为网卡配置静态IP地址 编辑文件/etc/network/interfaces: #sudo vi /etc/network/interfaces 并用下面的行来替换有关eth0的行: # The primary network interface auto eth0 iface eth0 inet static address 192.168.3.90 gateway 192.168.3.1 netmask 255.255.255.0 network 192.168.3.0 broadcast 192.168.3.255 将上面的ip地址等信息换成你自己就可以了. 用下面的命令使网络设置生效: #sudo /etc/init.d/networking restart 3. 设定第二个IP地址(虚拟IP地址) 编辑文件/etc/network/interfaces: #sudo vi /etc/network/interfaces 在该文件中添加如下的行: auto eth0:1 iface eth0:1 inet static address 192.168.1.60 netmask 255.255.255.0 network x.x.x.x broadcast x.x.x.x gateway x.x.x.x 根据你的情况填上所有诸如address,netmask,network,broadcast和gateways等信息. 用下面的命令使网络设置生效: #sudo /etc/init.d/networking restart 4. 设置主机名称(hostname) 使用下面的命令来查看当前主机的主机名称: #sudo /bin/hostname 使用下面的命令来设置当前主机的主机名称: #sudo /bin/hostname newname 系统启动时,它会从/etc/hostname来读取主机的名称. 5. 配置DNS 首先,你可以在/etc/hosts中加入一些主机名称和这些主机名称对应的IP地址,这是简单使用本机的静态查询. 要访问DNS 服务器来进行查询,需要设置/etc/resolv.conf文件. 假设DNS服务器的IP地址是192.168.3.2, 那么/etc/resolv.conf文件的内容应为: search test.com nameserver 192.168.3.2 --------------------------------------安装AMP服务 -------------------------------------- 如果采用Ubuntu Server CD开始安装时，可以选择安装，这系统会自动装上apache2,php5和mysql5。下面主要说明一下如果不是安装的Ubuntu server时的安装方法。 用命令在Ubuntu下架设Lamp其实很简单，用一条命令就完成。在终端输入以下命令： #sudo apt-get install apache2 mysql-server php5 php5-mysql php5-gd #phpmyadmin 装好后，mysql管理员是root，无密码，通过http://localhost/phpmyadmin就可以访问mysql了 修改 MySql 密码 终端下输入： #mysql -u root #mysql> GRANT ALL PRIVILEGES ON *.* TO root@localhost IDENTIFIED BY “123456″; ’123456‘是root的密码，可以自由设置，但最好是设个安全点的。 #mysql> quit; 退出mysql apache2的操作命令 启动：#sudo /etc/init.d/apache2 start 重启：#sudo /etc/init.d/apache2 restart 关闭：#sudo /etc/init.d/apache2 stop apache2的默认主目录：/var/www/
BANKEX / Plasma ClientWeb Client for Plasma Protocol
khoih-prog / AsyncWebServer WT32 ETH01This is Asynchronous HTTP and WebSocket Server Library for WT32_ETH01 (ESP32 + LAN8720). Now supporting using CString to save heap to send very large data and with examples to demo how to use beginChunkedResponse() to send large html in chunks
khoih-prog / AsyncUDP WT32 ETH01Fully Asynchronous UDP Library for WT32_ETH01 (ESP32 + LAN8720). The library is easy to use and includes support for Unicast, Broadcast and Multicast environments.
SnehaPathrose / DNSSpoofAndDetectdevelop 1) an on-path DNS packet injector, and 2) a passive DNS poisoning attack detector. Part 1: The DNS packet injector you are going to develop, named 'dnsinject', will capture the traffic from a network interface in promiscuous mode, and attempt to inject forged responses to selected DNS A requests with the goal to poison the resolver's cache. Your program should conform to the following specification: dnsinject [-i interface] [-h hostnames] expression -i Listen on network device <interface> (e.g., eth0). If not specified, dnsinject should select a default interface to listen on. The same interface should be used for packet injection. -h Read a list of IP address and hostname pairs specifying the hostnames to be hijacked. If '-h' is not specified, dnsinject should forge replies for all observed requests with the local machine's IP address as an answer. <expression> is a BPF filter that specifies a subset of the traffic to be monitored. This option is useful for targeting a single or a set of particular victims. The <hostnames> file should contain one IP and hostname pair per line, separated by whitespace, in the following format: 10.6.6.6 foo.example.com 10.6.6.6 bar.example.com 192.168.66.6 www.cs.stonybrook.edu Pay attention to the time needed for generating the spoofed response! Your code should be fast enough so that the injected reply reaches the victim sooner than the server's actual response. The spoofed packet and content should also be valid according to the initial DNS request, and the forged response should be accepted and processed normally by the victim. Part 2: The DNS poisoning attack detector you are going to develop, named 'dnsdetect', will capture the traffic from a network interface in promiscuous mode and detect DNS poisoning attack attempts, such as those generated by dnsinject. Detection will be based on identifying duplicate responses towards the same destination that contain different answers for the same A request, i.e., the observation of the attacker's spoofed response followed by the server's actual response. You should make every effort to avoid false positives, e.g., due to legitimate consecutive responses with different IP addresses for the same hostname due to round robin DNS load balancing. Your program should conform to the following specification: dnsdetect [-i interface] [-r tracefile] expression -i Listen on network device <interface> (e.g., eth0). If not specified, the program should select a default interface to listen on. -r Read packets from <tracefile> (tcpdump format). Useful for detecting DNS poisoning attacks in existing network traces. <expression> is a BPF filter that specifies a subset of the traffic to be monitored. Once an attack is detected, dnsdetect should print to stdout a detailed alert containing a printout of both the spoofed and legitimate responses. You can format the output in any way you like. Output must contain the detected DNS transaction ID, attacked domain name, and the original and malicious IP addresses - for example: 20160406-15:08:49.205618 DNS poisoning attempt TXID 0x5cce Request www.example.com Answer1 [List of IP addresses] Answer2 [List of IP addresses]
SOYJUN / Implement ODR ProtocolOverview For this assignment you will be developing and implementing : An On-Demand shortest-hop Routing (ODR) protocol for networks of fixed but arbitrary and unknown connectivity, using PF_PACKET sockets. The implementation is based on (a simplified version of) the AODV algorithm. Time client and server applications that send requests and replies to each other across the network using ODR. An API you will implement using Unix domain datagram sockets enables applications to communicate with the ODR mechanism running locally at their nodes. I shall be discussing the assignment in class on Wednesday, October 29, and Monday, November 3. The following should prove useful reference material for the assignment : Sections 15.1, 15.2, 15.4 & 15.6, Chapter 15, on Unix domain datagram sockets. PF_PACKET(7) from the Linux manual pages. You might find these notes made by a past CSE 533 student useful. Also, the following link http://www.pdbuchan.com/rawsock/rawsock.html contains useful code samples that use PF_PACKET sockets (as well as other code samples that use raw IP sockets which you do not need for this assignment, though you will be using these types of sockets for Assignment 4). Charles E. Perkins & Elizabeth M. Royer. “Ad-hoc On-Demand Distance Vector Routing.” Proceedings of the 2nd IEEE Workshop on Mobile Computing Systems and Applications, New Orleans, Louisiana, February 1999, pp. 90 - 100. The VMware environment minix.cs.stonybrook.edu is a Linux box running VMware. A cluster of ten Linux virtual machines, called vm1 through vm10, on which you can gain access as root and run your code have been created on minix. See VMware Environment Hosts for further details. VMware instructions takes you to a page that explains how to use the system. The ten virtual machines have been configured into a small virtual intranet of Ethernet LANs whose topology is (in principle) unknown to you. There is a course account cse533 on node minix, with home directory /users/cse533. In there, you will find a subdirectory Stevens/unpv13e , exactly as you are used to having on the cs system. You should develop your source code and makefiles for handing in accordingly. You will be handing in your source code on the minix node. Note that you do not need to link against the socket library (-lsocket) in Linux. The same is true for -lnsl and -lresolv. For example, take a look at how the LIBS variable is defined for Solaris, in /home/courses/cse533/Stevens/unpv13e_solaris2.10/Make.defines (on compserv1, say) : LIBS = ../libunp.a -lresolv -lsocket -lnsl -lpthread But if you take a look at Make.defines on minix (/users/cse533/Stevens/unpv13e/Make.defines) you will find only: LIBS = ../libunp.a -lpthread The nodes vm1 , . . . . . , vm10 are all multihomed : each has two (or more) interfaces. The interface ‘eth0 ’ should be completely ignored and is not to be used for this assignment (because it shows all ten nodes as if belonging to the same single Ethernet 192.168.1.0/24, rather than to an intranet composed of several Ethernets). Note that vm1 , . . . . . , vm10 are virtual machines, not real ones. One implication of this is that you will not be able to find out what their (virtual) IP addresses are by using nslookup and such. To find out these IP addresses, you need to look at the file /etc/hosts on minix. More to the point, invoking gethostbyname for a given vm will return to you only the (primary) IP address associated with the interface eth0 of that vm (which is the interface you will not be using). It will not return to you any other IP address for the node. Similarly, gethostbyaddr will return the vm node name only if you give it the (primary) IP address associated with the interface eth0 for the node. It will return nothing if you give it any other IP address for the node, even though the address is perfectly valid. Because of this, and because it will ease your task to be able to use gethostbyname and gethostbyaddr in a straightforward way, we shall adopt the (primary) IP addresses associated with interfaces eth0 as the ‘canonical’ IP addresses for the nodes (more on this below). Time client and server A time server runs on each of the ten vm machines. The client code should also be available on each vm so that it can be evoked at any of them. Normally, time clients/servers exchange request/reply messages using the TCP/UDP socket API that, effectively, enables them to receive service (indirectly, via the transport layer) from the local IP mechanism running at their nodes. You are to implement an API using Unix domain sockets to access the local ODR service directly (somewhat similar, in effect, to the way that raw sockets permit an application to access IP directly). Use Unix domain SOCK_DGRAM, rather than SOCK_STREAM, sockets (see Figures 15.5 & 15.6, pp. 418 - 419). API You need to implement a msg_send function that will be called by clients/servers to send requests/replies. The parameters of the function consist of : int giving the socket descriptor for write char* giving the ‘canonical’ IP address for the destination node, in presentation format int giving the destination ‘port’ number char* giving message to be sent int flag if set, force a route rediscovery to the destination node even if a non-‘stale’ route already exists (see below) msg_send will format these parameters into a single char sequence which is written to the Unix domain socket that a client/server process creates. The sequence will be read by the local ODR from a Unix domain socket that the ODR process creates for itself. Recall that the ‘canonical’ IP address for a vm node is the (primary) IP address associated with the eth0 interface for the node. It is what will be returned to you by a call to gethostbyname. Similarly, we need a msg_recv function which will do a (blocking) read on the application domain socket and return with : int giving socket descriptor for read char* giving message received char* giving ‘canonical’ IP address for the source node of message, in presentation format int* giving source ‘port’ number This information is written as a single char sequence by the ODR process to the domain socket that it creates for itself. It is read by msg_recv from the domain socket the client/server process creates, decomposed into the three components above, and returned to the caller of msg_recv. Also see the section below entitled ODR and the API. Client When a client is evoked at a node, it creates a domain datagram socket. The client should bind its socket to a ‘temporary’ (i.e., not ‘well-known’) sun_path name obtained from a call to tmpnam() (cf. line 10, Figure 15.6, p. 419) so that multiple clients may run at the same node. Note that tmpnam() is actually highly deprecated. You should use the mkstemp() function instead - look up the online man pages on minix (‘man mkstemp’) for details. As you run client code again and again during the development stage, the temporary files created by the calls to tmpnam / mkstemp start to proliferate since these files are not automatically removed when the client code terminates. You need to explicitly remove the file created by the client evocation by issuing a call to unlink() or to remove() in your client code just before the client code exits. See the online man pages on minix (‘man unlink’, ‘man remove’) for details. The client then enters an infinite loop repeating the steps below. The client prompts the user to choose one of vm1 , . . . . . , vm10 as a server node. Client msg_sends a 1 or 2 byte message to server and prints out on stdout the message client at node vm i1 sending request to server at vm i2 (In general, throughout this assignment, “trace” messages such as the one above should give the vm names and not IP addresses of the nodes.) Client then blocks in msg_recv awaiting response. This attempt to read from the domain socket should be backed up by a timeout in case no response ever comes. I leave it up to you whether you ‘wrap’ the call to msg_recv in a timeout, or you implement the timeout inside msg_recv itself. When the client receives a response it prints out on stdout the message client at node vm i1 : received from vm i2 <timestamp> If, on the other hand, the client times out, it should print out the message client at node vm i1 : timeout on response from vm i2 The client then retransmits the message out, setting the flag parameter in msg_send to force a route rediscovery, and prints out an appropriate message on stdout. This is done only once, when a timeout for a given message to the server occurs for the first time. Client repeats steps 1. - 3. Server The server creates a domain datagram socket. The server socket is assumed to have a (node-local) ‘well-known’ sun_path name which it binds to. This ‘well-known’ sun_path name is designated by a (network-wide) ‘well-known’ ‘port’ value. The time client uses this ‘port’ value to communicate with the server. The server enters an infinite sequence of calls to msg_recv followed by msg_send, awaiting client requests and responding to them. When it responds to a client request, it prints out on stdout the message server at node vm i1 responding to request from vm i2 ODR The ODR process runs on each of the ten vm machines. It is evoked with a single command line argument which gives a “staleness” time parameter, in seconds. It uses get_hw_addrs (available to you on minix in ~cse533/Asgn3_code) to obtain the index, and associated (unicast) IP and Ethernet addresses for each of the node’s interfaces, except for the eth0 and lo (loopback) interfaces, which should be ignored. In the subdirectory ~cse533/Asgn3_code (/users/cse533/Asgn3_code) on minix I am providing you with two functions, get_hw_addrs and prhwaddrs. These are analogous to the get_ifi_info_plus and prifinfo_plus of Assignment 2. Like get_ifi_info_plus, get_hw_addrs uses ioctl. get_hw_addrs gets the (primary) IP address, alias IP addresses (if any), HW address, and interface name and index value for each of the node's interfaces (including the loopback interface lo). prhwaddrs prints that information out. You should modify and use these functions as needed. Note that if an interface has no HW address associated with it (this is, typically, the case for the loopback interface lo for example), then ioctl returns get_hw_addrs a HW address which is the equivalent of 00:00:00:00:00:00 . get_hw_addrs stores this in the appropriate field of its data structures as it would with any HW address returned by ioctl, but when prhwaddrs comes across such an address, it prints a blank line instead of its usual ‘HWaddr = xx:xx:xx:xx:xx:xx’. The ODR process creates one or more PF_PACKET sockets. You will need to try out PF_PACKET sockets for yourselves and familiarize yourselves with how they behave. If, when you read from the socket and provide a sockaddr_ll structure, the kernel returns to you the index of the interface on which the incoming frame was received, then one socket will be enough. Otherwise, somewhat in the manner of Assignment 2, you shall have to create a PF_PACKET socket for every interface of interest (which are all the interfaces of the node, excluding interfaces lo and eth0 ), and bind a socket to each interface. Furthermore, if the kernel also returns to you the source Ethernet address of the frame in the sockaddr_ll structure, then you can make do with SOCK_DGRAM type PF_PACKET sockets; otherwise you shall have to use SOCK_RAW type sockets (although I would prefer you to use SOCK_RAW type sockets anyway, even if it turns out you can make do with SOCK_DGRAM type). The socket(s) should have a protocol value (no larger than 0xffff so that it fits in two bytes; this value is given as a network-byte-order parameter in the call(s) to function socket) that identifies your ODR protocol. The <linux/if_ether.h> include file (i.e., the file /usr/include/linux/if_ether.h) contains protocol values defined for the standard protocols typically found on an Ethernet LAN, as well as other values such as ETH_P_ALL. You should set protocol to a value of your choice which is not a <linux/if_ether.h> value, but which is, hopefully, unique to yourself. Remember that you will all be running your code using the same root account on the vm1 , . . . . . , vm10 nodes. So if two of you happen to choose the same protocol value and happen to be running on the same vm node at the same time, your applications will receive each other’s frames. For that reason, try to choose a protocol value for the socket(s) that is likely to be unique to yourself (something based on your Stony Brook student ID number, for example). This value effectively becomes the protocol value for your implementation of ODR, as opposed to some other cse 533 student's implementation. Because your value of protocol is to be carried in the frame type field of the Ethernet frame header, the value chosen should be not less than 1536 (0x600) so that it is not misinterpreted as the length of an Ethernet 802.3 frame. Note from the man pages for packet(7) that frames are passed to and from the socket without any processing in the frame content by the device driver on the other side of the socket, except for calculating and tagging on the 4-byte CRC trailer for outgoing frames, and stripping that trailer before delivering incoming frames to the socket. Nevertheless, if you write a frame that is less than 60 bytes, the necessary padding is automatically added by the device driver so that the frame that is actually transmitted out is the minimum Ethernet size of 64 bytes. When reading from the socket, however, any such padding that was introduced into a short frame at the sending node to bring it up to the minimum frame size is not stripped off - it is included in what you receive from the socket (thus, the minimum number of bytes you receive should never be less than 60). Also, you will have to build the frame header for outgoing frames yourselves (assuming you use SOCK_RAW type sockets). Bear in mind that the field values in that header have to be in network order. The ODR process also creates a domain datagram socket for communication with application processes at the node, and binds the socket to a ‘well known’ sun_path name for the ODR service. Because it is dealing with fixed topologies, ODR is, by and large, considerably simpler than AODV. In particular, discovered routes are relatively stable and there is no need for all the paraphernalia that goes with the possibility of routes changing (such as maintenance of active nodes in the routing tables and timeout mechanisms; timeouts on reverse links; lifetime field in the RREP messages; etc.) Nor will we be implementing source_sequence_#s (in the RREQ messages), and dest_sequence_# (in RREQ and RREP messages). In reality, we should (though we will not, for the sake of simplicity, be doing so) implement some sort of sequence number mechanism, or some alternative mechanism such as split-horizon for example, if we are to avoid possible scenarios of routing loops in a “count to infinity” context (I shall explain this point in class). However, we want ODR to discover shortest-hop paths, and we want it to do so in a reasonably efficient manner. This necessitates having one or two aspects of its operations work in a different, possibly slightly more complicated, way than AODV does. ODR has several basic responsibilities : Build and maintain a routing table. For each destination in the table, the routing table structure should include, at a minimum, the next-hop node (in the form of the Ethernet address for that node) and outgoing interface index, the number of hops to the destination, and a timestamp of when the the routing table entry was made or last “reconfirmed” / updated. Note that a destination node in the table is to be identified only by its ‘canonical’ IP address, and not by any other IP addresses the node has. Generate a RREQ in response to a time client calling msg_send for a destination for which ODR has no route (or for which a route exists, but msg_send has the flag parameter set or the route has gone ‘stale’ – see below), and ‘flood’ the RREQ out on all the node’s interfaces (except for the interface it came in on and, of course, the interfaces eth0 and lo). Flooding is done using an Ethernet broadcast destination address (0xff:ff:ff:ff:ff:ff) in the outgoing frame header. Note that a copy of the broadcast packet is supposed to / might be looped back to the node that sends it (see p. 535 in the Stevens textbook). ODR will have to take care not to treat these copies as new incoming RREQs. Also note that ODR at the client node increments the broadcast_id every time it issues a new RREQ for any destination node. When a RREQ is received, ODR has to generate a RREP if it is at the destination node, or if it is at an intermediate node that happens to have a route (which is not ‘stale’ – see below) to the destination. Otherwise, it must propagate the RREQ by flooding it out on all the node’s interfaces (except the interface the RREQ arrived on). Note that as it processes received RREQs, ODR should enter the ‘reverse’ route back to the source node into its routing table, or update an existing entry back to the source node if the RREQ received shows a shorter-hop route, or a route with the same number of hops but going through a different neighbour. The timestamp associated with the table entry should be updated whenever an existing route is either “reconfirmed” or updated. Obviously, if the node is going to generate a RREP, updating an existing entry back to the source node with a more efficient route, or a same-hops route using a different neighbour, should be done before the RREP is generated. Unlike AODV, when an intermediate node receives a RREQ for which it generates a RREP, it should nevertheless continue to flood the RREQ it received if the RREQ pertains to a source node whose existence it has heretofore been unaware of, or the RREQ gives it a more efficient route than it knew of back to the source node (the reason for continuing to flood the RREQ is so that other nodes in the intranet also become aware of the existence of the source node or of the potentially more optimal reverse route to it, and update their tables accordingly). However, since an RREP for this RREQ is being sent by our node, we do not want other nodes who receive the RREQ propagated by our node, and who might be in a position to do so, to also send RREPs. So we need to introduce a field in the RREQ message, not present in the AODV specifications, which acts like a “RREP already sent” field. Our node sets this field before further propagating the RREQ and nodes receiving an RREQ with this field set do not send RREPs in response, even if they are in a position to do so. ODR may, of course, receive multiple, distinct instances of the same RREQ (the combination of source_addr and broadcast_id uniquely identifies the RREQ). Such RREQs should not be flooded out unless they have a lower hop count than instances of that RREQ that had previously been received. By the same token, if ODR is in a position to send out a RREP, and has already done so for this, now repeating, RREQ , it should not send out another RREP unless the RREQ shows a more efficient, previously unknown, reverse route back to the source node. In other words, ODR should not generate essentially duplicative RREPs, nor generate RREPs to instances of RREQs that reflect reverse routes to the source that are not more efficient than what we already have. Relay RREPs received back to the source node (this is done using the ‘reverse’ route entered into the routing table when the corresponding RREQ was processed). At the same time, a ‘forward’ path to the destination is entered into the routing table. ODR could receive multiple, distinct RREPs for the same RREQ. The ‘forward’ route entered in the routing table should be updated to reflect the shortest-hop route to the destination, and RREPs reflecting suboptimal routes should not be relayed back to the source. In general, maintaining a route and its associated timestamp in the table in response to RREPs received is done in the same manner described above for RREQs. Forward time client/server messages along the next hop. (The following is important – you will lose points if you do not implement it.) Note that such application payload messages (especially if they are the initial request from the client to the server, rather than the server response back to the client) can be like “free” RREPs, enabling nodes along the path from source (client) to destination (server) node to build a reverse path back to the client node whose existence they were heretofore unaware of (or, possibly, to update an existing route with a more optimal one). Before it forwards an application payload message along the next hop, ODR at an intermediate node (and also at the final destination node) should use the message to update its routing table in this way. Thus, calls to msg_send by time servers should never cause ODR at the server node to initiate RREQs, since the receipt of a time client request implies that a route back to the client node should now exist in the routing table. The only exception to this is if the server node has a staleness parameter of zero (see below). A routing table entry has associated with it a timestamp that gives the time the entry was made into the table. When a client at a node calls msg_send, and if an entry for the destination node already exists in the routing table, ODR first checks that the routing information is not ‘stale’. A stale routing table entry is one that is older than the value defined by the staleness parameter given as a command line argument to the ODR process when it is executed. ODR deletes stale entries (as well as non-stale entries when the flag parameter in msg_send is set) and initiates a route rediscovery by issuing a RREQ for the destination node. This will force periodic updating of the routing tables to take care of failed nodes along the current path, Ethernet addresses that might have changed, and so on. Similarly, as RREQs propagate through the intranet, existing stale table entries at intermediate nodes are deleted and new route discoveries propagated. As noted above when discussing the processing of RREQs and RREPs, the associated timestamp for an existing table entry is updated in response to having the route either “reconfirmed” or updated (this applies to both reverse routes, by virtue of RREQs received, and to forward routes, by virtue of RREPs). Finally, note that a staleness parameter of 0 essentially indicates that the discovered route will be used only once, when first discovered, and then discarded. Effectively, an ODR with staleness parameter 0 maintains no real routing table at all ; instead, it forces route discoveries at every step of its operation. As a practical matter, ODR should be run with staleness parameter values that are considerably larger than the longest RTT on the intranet, otherwise performance will degrade considerably (and collapse entirely as the parameter values approach 0). Nevertheless, for robustness, we need to implement a mechanism by which an intermediate node that receives a RREP or application payload message for forwarding and finds that its relevant routing table entry has since gone stale, can intiate a RREQ to rediscover the route it needs. RREQ, RREP, and time client/server request/response messages will all have to be carried as encapsulated ODR protocol messages that form the data payload of Ethernet frames. So we need to design the structure of ODR protocol messages. The format should contain a type field (0 for RREQ, 1 for RREP, 2 for application payload ). The remaining fields in an ODR message will depend on what type it is. The fields needed for (our simplified versions of AODV’s) RREQ and RREP should be fairly clear to you, but keep in mind that you need to introduce two extra fields: The “RREP already sent” bit or field in RREQ messages, as mentioned above. A “forced discovery” bit or field in both RREQ and RREP messages: When a client application forces route rediscovery, this bit should be set in the RREQ issued by the client node ODR. Intermediate nodes that are not the destination node but which do have a route to the destination node should not respond with RREPs to an RREQ which has the forced discovery field set. Instead, they should continue to flood the RREQ so that it eventually reaches the destination node which will then respond with an RREP. The intermediate nodes relaying such an RREQ must update their ‘reverse’ route back to the source node accordingly, even if the new route is less efficient (i.e., has more hops) than the one they currently have in their routing table. The destination node responds to the RREQ with an RREP in which this field is also set. Intermediate nodes that receive such a forced discovery RREP must update their ‘forward’ route to the destination node accordingly, even if the new route is less efficient (i.e., has more hops) than the one they currently have in their routing table. This behaviour will cause a forced discovery RREQ to be responded to only by the destination node itself and not any other node, and will cause intermediate nodes to update their routing tables to both source and destination nodes in accordance with the latest routing information received, to cover the possibility that older routes are no longer valid because nodes and/or links along their paths have gone down. A type 2, application payload, message needs to contain the following type of information : type = 2 ‘canonical’ IP address of source node ‘port’ number of source application process (This, of course, is not a real port number in the TCP/UDP sense, but simply a value that ODR at the source node uses to designate the sun_path name for the source application’s domain socket.) ‘canonical’ IP address of destination node ‘port’ number of destination application process (This is passed to ODR by the application process at the source node when it calls msg_send. Its designates the sun_path name for an application’s domain socket at the destination node.) hop count (This starts at 0 and is incremented by 1 at each hop so that ODR can make use of the message to update its routing table, as discussed above.) number of bytes in application message The fields above essentially constitute a ‘header’ for the ODR message. Note that fields which you choose to have carry numeric values (rather than ascii characters, for example) must be in network byte order. ODR-defined numeric-valued fields in type 0, RREQ, and type 1, RREP, messages must, of course, also be in network byte order. Also note that only the ‘canonical’ IP addresses are used for the source and destination nodes in the ODR header. The same has to be true in the headers for type 0, RREQ, and type 1, RREP, messages. The general rule is that ODR messages only carry ‘canonical’ IP node addresses. The last field in the type 2 ODR message is essentially the data payload of the message. application message given in the call to msg_send An ODR protocol message is encapsulated as the data payload of an Ethernet frame whose header it fills in as follows : source address = Ethernet address of outgoing interface of the current node where ODR is processing the message. destination address = Ethernet broadcast address for type 0 messages; Ethernet address of next hop node for type 1 & 2 messages. protocol field = protocol value for the ODR PF_PACKET socket(s). Last but not least, whenever ODR writes an Ethernet frame out through its socket, it prints out on stdout the message ODR at node vm i1 : sending frame hdr src vm i1 dest addr ODR msg type n src vm i2 dest vm i3 where addr is in presentation format (i.e., hexadecimal xx:xx:xx:xx:xx:xx) and gives the destination Ethernet address in the outgoing frame header. Other nodes in the message should be identified by their vm name. A message should be printed out for each packet sent out on a distinct interface. ODR and the API When the ODR process first starts, it must construct a table in which it enters all well-known ‘port’ numbers and their corresponding sun_path names. These will constitute permanent entries in the table. Thereafter, whenever it reads a message off its domain socket, it must obtain the sun_path name for the peer process socket and check whether that name is entered in the table. If not, it must select an ‘ephemeral’ ‘port’ value by which to designate the peer sun_path name and enter the pair < port value , sun_path name > into the table. Such entries cannot be permanent otherwise the table will grow unboundedly in time, with entries surviving for ever, beyond the peer processes’ demise. We must associate a time_to_live field with a non-permanent table entry, and purge the entry if nothing is heard from the peer for that amount of time. Every time a peer process for which a non-permanent table entry exists communicates with ODR, its time_to_live value should be reinitialized. Note that when ODR writes to a peer, it is possible for the write to fail because the peer does not exist : it could be a ‘well-known’ service that is not running, or we could be in the interval between a process with a non-permanent table entry terminating and the expiration of its time_to_live value. Notes A proper implementation of ODR would probably require that RREQ and RREP messages be backed up by some kind of timeout and retransmission mechanism since the network transmission environment is not reliable. This would considerably complicate the implementation (because at any given moment, a node could have multiple RREQs that it has flooded out, but for which it has still not received RREPs; the situation is further complicated by the fact that not all intermediate nodes receiving and relaying RREQs necessarily lie on a path to the destination, and therefore should expect to receive RREPs), and, learning-wise, would not add much to the experience you should have gained from Assignment 2.
aneisch / Report IPSend IP address from eth0 and wlan0 to email address on boot.
blue-pho3nix / Zshrc With IpThis is based on ZephyFoxy's .zshrc file. I added lolcat and some other fun stuff you might like. You still get the eth0, tun0. wlan0 and I added the Virtual Hacking Lab's ppp0.
AI6YP / Eth01 Evoeth01-evo board experiments
p0zn / P0znMITMAdvanced MITM Tool
