ethernet

问题 Building an application using dpdk-v18.02 and getting an error as "no valid ports". I tried dpdk-v19.02 and it's giving the same error. This is the error: EAL: Detected 40 lcore(s) EAL: Multi-process socket /var/run/.rte_unix EAL: Probing VFIO support... EAL: PCI device 0000:04:00.0 on NUMA socket 0 EAL: probe driver: 10ee:9038 xnic EAL: Requested device 0000:04:00.0 cannot be used EAL: Error - exiting with code: 1 Cause: Error: no valid ports The port is already bound to the driver: dpdk

问题 i have some scenarios in which i need to redirect user to some settings in device(rooted device).example i am redirecting user to wifi settings page like below Intent intent = new Intent(Settings.ACTION_WIFI_IP_SETTINGS); intent.putExtra("extra_prefs_show_button_bar", true); startActivity(intent); same way i need to redirect user to ethernet settings page i am including screen shot of that page because some phones not containing ethernet settings some of may not aware. 回答1: I am aware the

问题 I've created a very minimal image for the jetson nano with the recepe: inherit core-image inherit distro_features_check REQUIRED_DISTRO_FEATURES = "x11" IMAGE_FEATURES += "package-management splash" CORE_OS = "packagegroup-core-boot \ packagegroup-core-x11 \ packagegroup-xfce-base \ kernel-modules \ " WIFI_SUPPORT = " \ ifupdown \ dropbear\ crda \ iw \ " DEV_SDK_INSTALL = " \ opencv \ opencv-samples \ gstreamer1.0-omx-tegra \ python-numpy \ binutils \ binutils-symlinks \ coreutils \ cpp \ cpp

问题 I am trying to do some experiments with Arduino, Ethernet Shield and Xbee Shield. I demonstrate my set up board like this: Group 1: Arduino Uno + Xbee shield : broadcast the signal Group 2: Arduino Uno + Xbee shield + Ethernet shield: receive the signal from group 1, get the signal strength from AT command and print it into the browser. The problem here is I can't get the result after sending to the Serial my ATDB command, actually, I am not sure it did worked as I expected. Here is the code

问题 I'm really confused about how the basic idea of updating the switch table works. In the case that the CRC is wrong it still updates the SMAC to use it next time maybe? Maybe because the error could be there (SMAC) the switch drops the SMAC with the message? Another thing is what happened first, update the table or first send the message in case of store&forward mode? 回答1: first look at this picture The Scenario is PC1 10.0.0.2 try to Ping PC3 10.0.0.4 : PC1 Send ARP Message (BroadCast)

问题 I downloaded WinDDK and am using ndisprot 5x to broadcast raw ethernet packets from my user app, specifying destination MAC all 0xff's, on large and repetitive data sets it doesn't seem to be very productive. What currently works great is a loopback - specifying destination and source MAC's as my own I get needed speed, but the packet never leaves my network card. Maybe I am missing some ndis driver options and wait for a broadcast to complete using this sample MS driver? All I want is the

问题 Recently I am trying to filter the inbound packet from the pcap file by libpcap in C/C++. Here is partial code. pcap = pcap_open_offline(argv[0], errbuf); if (pcap == NULL) { fprintf(stderr, "error reading pcap file: %s\n", errbuf); exit(1); } char filter_exp[] = "inbound"; struct bpf_program pgm; if (pcap_compile(pcap, &pgm, filter_exp, 0, PCAP_NETMASK_UNKNOWN) == -1) { printf("Bad filter - %s\n", pcap_geterr(pcap)); return 1; } if (pcap_setfilter(pcap, &pgm) == -1) { printf("Error setting

问题 An Ethernet Frame Check Sequence is always appended to the end of a frame in the Data Link Layer. Why is it appended to the end of the frame and not somewhere else? I thought about it and think it might have something to do with how e.g. CRC-checksums are calculated and that it's easier performed by hardware if the structure of a frame is header+payload+crc rather than header+crc+payload. CRC performs an XOR division of the form (data+padding)/divisor, and for the final frame the padding is

问题 After some search on the Internet,I came to know that, following are the list of options available to get/set parameters to the ethernet interface. SIOCETHTOOL SIOCGMIIPHY SIOCGIFFLAGS I even saw some 'stackoverflow' questions regarding the usage of SIOCETHTOOL. But the questions I have are: Comparison of these three interfaces (means API's) in terms of the features they offer and support in multiple kernels. When should one of these options should be preferred over the others. I hardly find

问题 I would like to know is it possible to do memcpy by bits instead of bytes ? I am writing a C code for Ethernet frame with VLAN tagging, in which I need to fill different values for VLAN header attributes (PCP-3bits,DEI-1bit,VID-12bits). How can I do memcpy to those bits, or any other possibility to fill values to those attributes in bits. Thanks in advance ! 回答1: No. Bits are not addressable (meaning that it is not possible to read them and only them directly from memory. They have no address