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systemd-networkd 不接收 dhcp 請求

tag-icon • tag-icon networking dhcp systemd
systemd-networkd 不接收 dhcp 請求

主機、容器：fc21

$ systemctl start systemd-networkd.service
$ systemd-nspawn -b -D `pwd` -M m1  --private-network --network-veth

....在容器中：

$ systemctl start systemd-networkd.service
$ ip addr
2: host0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether c6:a1:72:9b:16:08 brd ff:ff:ff:ff:ff:ff
    inet 169.254.215.78/16 brd 169.254.255.255 scope link host0
       valid_lft forever preferred_lft forever
    inet6 fe80::c4a1:72ff:fe9b:1608/64 scope link 
       valid_lft forever preferred_lft forever

-> 容器只取得一個 ipv4LL 位址，而不是一個漂亮的 dhcp 分配的位址。

為什麼 ？

在主機上tcpdump -i v1-m1顯示根據介面 host0 的 systemd-networkd 預設配置來自 m1 容器的 DHCP 請求：

$ sudo tcpdump -i ve-m1
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on ve-m1, link-type EN10MB (Ethernet), capture size 262144 bytes
11:57:18.768736 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from c6:a1:72:9b:16:08 (oui Unknown), length 271
11:57:19.757532 ARP, Request who-has 169.254.215.78 tell 0.0.0.0, length 28

在主機上，systemd-networkd 的 strace 顯示它正在偵聽 UDP DHCP 伺服器端口但從不讀取它：

socket(PF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 12
setsockopt(12, SOL_IP, IP_TOS, [192], 4) = 0
setsockopt(12, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
setsockopt(12, SOL_IP, IP_PKTINFO, [1], 4) = 0
setsockopt(12, SOL_SOCKET, SO_BROADCAST, [1], 4) = 0
bind(12, {sa_family=AF_INET, sin_port=htons(67), sin_addr=inet_addr("0.0.0.0")}, 16) = 0
epoll_ctl(3, EPOLL_CTL_ADD, 12, {EPOLLIN, {u32=2522795824, u64=139692039130928}}) = 0
writev(2, [{"DHCP SERVER: STARTED", 20}, {"\n", 1}], 2) = 21

我檢查沒有其他進程正在偵聽相同 udp 連接埠：

$ lsof |grep -i udp |grep -i bootps
systemd-n 16276       systemd-network   12u     IPv4             265473       0t0        UDP *:bootps

現在我的調試技巧已經結束了。我的問題是：如何進一步調試？即有沒有辦法取得有關 dhcp 請求可能遺失的位置以及原因的資訊？

答案1

嘗試以下命令：

$ systemctl stop firewalld.service

嘆

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