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pin / tftp

TFTP server and client library for Golang

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UDP fd leak

leslie-qiwa opened this issue · comments

commented

Thanks for the package!

In our production, we found FD leak happened from time to time.

Result of netstat.

udp6       0      0 :::35808                :::*                                1/imgsvc
udp6       0      0 :::60384                :::*                                1/imgsvc
udp6       0      0 :::35811                :::*                                1/imgsvc
udp6       0      0 :::48099                :::*                                1/imgsvc
udp6       0      0 :::48101                :::*                                1/imgsvc
udp6       0      0 :::44006                :::*                                1/imgsvc
udp6       0      0 :::60391                :::*                                1/imgsvc
udp6       0      0 :::39913                :::*                                1/imgsvc

Result of lsof

imgsvc    1 root   97u     IPv6 2499572613      0t0        UDP *:39620
imgsvc    1 root   98u     IPv6 2499572625      0t0        UDP *:53887
imgsvc    1 root   99u     IPv6 2499574158      0t0        UDP *:35839
imgsvc    1 root  100u     IPv6 2499571638      0t0        UDP *:40739
imgsvc    1 root  101u     IPv6 2499572645      0t0        UDP *:39966
imgsvc    1 root  102u     IPv6 2499574181      0t0        UDP *:37082
imgsvc    1 root  103u     IPv6 2499572675      0t0        UDP *:60167
imgsvc    1 root  104u     IPv6 2499572703      0t0        UDP *:60581
imgsvc    1 root  105u     IPv6 2499572717      0t0        UDP *:60832
imgsvc    1 root  106u     IPv6 2499575882      0t0        UDP *:51438
imgsvc    1 root  107u     IPv6 2499575159      0t0        UDP *:40391
imgsvc    1 root  108u     IPv6 2499575980      0t0        UDP *:47018
imgsvc    1 root  109u     IPv6 2499574463      0t0        UDP *:48728
imgsvc    1 root  110u     IPv6 2499574738      0t0        UDP *:41585
imgsvc    1 root  111u     IPv6 2499579012      0t0        UDP *:50600
imgsvc    1 root  112u     IPv6 2499577856      0t0        UDP *:52925
imgsvc    1 root  113u     IPv6 2499580893      0t0        UDP *:58937
imgsvc    1 root  114u     IPv6 2499581898      0t0        UDP *:56533
imgsvc    1 root  115u     IPv6 2499600282      0t0        UDP *:51884
imgsvc    1 root  116u     IPv6 2499602688      0t0        UDP *:48947
imgsvc    1 root  117u     IPv6 2499600345      0t0        UDP *:37447

We only have one readHandler like example in README, so the leak seems coming from the server itself. Looking at the codes https://github.com/pin/tftp/blob/master/server.go#L416, seems like connection is not closed, so can you please help check if it is the root cause or not.

			conn, err := net.ListenUDP("udp", listenAddr)
			if err != nil {
				return err
			}
			rf.conn = &connConnection{conn: conn}
		}
		if s.sendAEnable { /* senderAnticipate if enabled in server */
			rf.sendA.enabled = true /* pass enable from server to sender */
			sendAInit(&rf.sendA, datagramLength, s.sendAWinSz)
		}
		s.wg.Add(1)
		go func() {
			if s.readHandler != nil {
				err := s.readHandler(filename, rf)
				if err != nil {
					rf.abort(err)
				}
			} else {
				rf.abort(fmt.Errorf("server does not support read requests"))
			}
			s.wg.Done()
		}()
commented

@leslie-qiwa, please reopen if you still observe FD leak. Thank you for the fix!