Skip to content

Bind the random UDP source port exclusively on Windows #158

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
mame merged 1 commit into from
Oct 14, 2026
Merged

Bind the random UDP source port exclusively on Windows #158

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 13 additions & 0 deletions lib/resolv.rb
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -691,6 +691,19 @@ def self.free_request_id(host, port, id) # :nodoc:
def self.bind_random_port(udpsock, bind_host="0.0.0.0") # :nodoc:
udpsock.bind(bind_host, 0)
end
when /mswin|mingw/
# Sequential port assignment
def self.bind_random_port(udpsock, bind_host="0.0.0.0") # :nodoc:
# SO_EXCLUSIVEADDRUSE: make bind fail if another socket already uses the port
udpsock.setsockopt(Socket::SOL_SOCKET, ~Socket::SO_REUSEADDR, 1)
begin
# Ephemeral port number range recommended by RFC 6056
port = random(1024..65535)
udpsock.bind(bind_host, port)
rescue Errno::EADDRINUSE, Errno::EACCES
retry
end
end
else
# Sequential port assignment
def self.bind_random_port(udpsock, bind_host="0.0.0.0") # :nodoc:
Expand Down
Loading