我在qemunetworking上遇到一些麻烦。 我正在尝试简单的select（用户）。 我运行的qemu命令是这样的：
./qemu-xilinx/arm-softmmu/qemu-system-arm \ -M xilinx-zynq-a9 -m 1024 -serial null -serial mon:stdio \ -dtb /homes/cperivol/Sandbox/xilinx-zynq-bootstrap/resources/devicetree.dtb \ -kernel /homes/cperivol/Sandbox/xilinx-zynq-bootstrap/resources/zImage \ -initrd /homes/cperivol/Sandbox/xilinx-zynq-bootstrap/resources.qemu/ramdisk.img \ -nographic -s -net dump,file=/tmp/dhcpdump.pcap -net nic \ -net user,net=192.168.1.0/24 命令的有趣部分在最后。 我基本上将所有的TCP / UDPstream量转储到/tmp/dhcpdump.pcap 。
那么从qemu我做：
$ udhcpc -t 1 -T 10 -n udhcpc (v1.22.0.git) started Sending discover... No lease, failing
从主机上读取从thcpdump转储：
(host) $ tcpdump -e -v -s 0 -nr /tmp/dhcpdump.pca [*other very similar requests done by the kernel at startup*] 15:00:48.874298 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: (tos 0x10, ttl 64, id 20, offset 0, flags [none], proto UDP (17), length 576) 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548, xid 0x7a5d3455, Flags [none] Your-IP 192.168.1.15 Server-IP 192.168.1.2 Client-Ethernet-Address 4a:3d:06:fb:d3:52 Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Offer Server-ID Option 54, length 4: 192.168.1.2 Subnet-Mask Option 1, length 4: 255.255.255.0 Default-Gateway Option 3, length 4: 192.168.1.2 Domain-Name-Server Option 6, length 4: 192.168.1.3 Lease-Time Option 51, length 4: 86400 15:00:48.874348 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 326: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 312) 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 284, xid 0x7a5d3455, Flags [none] Client-Ethernet-Address 4a:3d:06:fb:d3:52 Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Discover Client-ID Option 61, length 7: ether 4a:3d:06:fb:d3:52 MSZ Option 57, length 2: 576 Parameter-Request Option 55, length 7: Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname Domain-Name, BR, NTP Vendor-Class Option 60, length 16: "udhcp 1.22.0.git"
问题在于我无法获得租约，但从学术angular度来看，我最感兴趣的是为什么在客户发现问题之前获得优惠。
编辑：这里是完整的转储：
(host) $ tcpdump -e -s 0 -nr /tmp/dhcpdump.pcap reading from file /tmp/dhcpdump.pcap, link-type EN10MB (Ethernet) 14:34:12.400162 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:34:12.400203 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 548 14:34:14.518984 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:34:14.519023 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 548 14:34:18.227926 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:34:18.227976 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 548 14:34:24.718934 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:34:24.719064 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 548 14:34:36.072184 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:34:36.072301 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 548 14:34:55.938462 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:34:55.938583 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 548 14:35:21.051476 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:35:21.051526 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 548 14:35:22.872058 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:35:22.872175 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 548 14:35:26.055294 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:35:26.055339 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 548 14:35:31.619870 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:35:31.619966 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 548 14:35:41.351737 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:35:41.351798 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 548 14:35:58.377559 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:35:58.377601 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 548 14:51:15.522553 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:51:15.522601 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 326: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 284 14:51:18.060428 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:51:18.060460 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 326: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 284 14:52:22.487889 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:52:22.487939 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 326: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 284 14:52:30.883654 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:52:30.883691 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 326: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 284 14:52:39.279423 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:52:39.279462 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 326: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 284 14:59:42.818215 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 14:59:42.818263 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 326: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 284 15:00:07.938782 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 15:00:07.938829 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 326: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 284 15:00:28.348337 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 15:00:28.348378 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 326: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 284 15:00:48.874298 52:55:c0:a8:01:02 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 590: 192.168.1.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 548 15:00:48.874348 4a:3d:06:fb:d3:52 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 326: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 4a:3d:06:fb:d3:52, length 284