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6dfcbb6282Ruby 3.4 shipped support for happy eyeballs in `Socket.tcp` and `TCPSocket`. However, our `FinalDestination::HTTP` wrapper was performing a DNS lookup and passing IP addresses one at a time when opening the socket. That meant that we didn't benefit from the new Ruby feature in most Discourse features. This commit factors the strategy. Now, `FinalDestination::HTTP` encodes the DNS result and passes it to the underlying implementation as a fake hostname string. A patch to `Addrinfo` detects this fake hostname and returns the given IPs instead of performing its own lookup. For this Addrinfo patch to work, we also had to patch `TCPSocket` so that it uses the ruby-based `Socket.tcp` rather than its native C socket-opening code. The result is that we now get the benefit of the native Ruby 'Happy Eyeballs' support for concurrent ipv4 and ipv6 connections. All this patching of low-level ruby classes is not ideal, but there is no native way to control name resolution in `Net::HTTP` or its dependencies.
35 lines
965 B
Ruby
Vendored
35 lines
965 B
Ruby
Vendored
# frozen_string_literal: true
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class FinalDestination::HTTP < Net::HTTP
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# Ruby's Happy Eyeballs implementation will try every IP address at 250ms intervals.
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# Limit the total to avoid DoS via a high-ip-count DNS response.
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MAX_ADDRESSES_PER_FAMILY = 5
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def connect
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raise ArgumentError.new("address cannot be nil or empty") if @address.blank?
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return super if @ipaddr
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ips = FinalDestination::SSRFDetector.lookup_and_filter_ips(@address, timeout: @connect_timeout)
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if proxy?
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self.ipaddr = ips.first
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return super
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end
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@final_destination_token = FinalDestination::Connector.encode(@address, capped_addresses(ips))
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super
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ensure
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@final_destination_token = nil
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end
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def conn_address
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@final_destination_token || super
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end
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private
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def capped_addresses(ips)
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ipv6, ipv4 = ips.partition { |ip| ip.include?(":") }
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ipv6.first(MAX_ADDRESSES_PER_FAMILY) + ipv4.first(MAX_ADDRESSES_PER_FAMILY)
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end
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end
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