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Zhou Yuefu
1da5cc2951
When dnsmasq forks a child to handle a TCP connection, the child inherits copies of all listening sockets. These are never used but keep the underlying sockets alive in the kernel. If a network interface is removed and re-added while a child is running, the parent's attempt to re-bind fails with EADDRINUSE because the child still holds a reference. Close all listener fds (UDP and TCP) in the child immediately after fork in both do_tcp_connection() and swap_to_tcp(). [Original patch extended by Simon Kelley to include the TFTP listening socket, and to extend the existing race-protection scheme for the netlink socket to the listening sockets. Any bugs are my responsibility.]