login-common: Change process title to show different connection types Separate pre-login connections, proxy connections and post-login TLS proxies.

Changed type of internet port values to in_port_t everywhere. Created special SET_IN_PORT setting type for internet port values. Created net_str2port() for parsing internet port values. Removed several atoi() invocations in the process.

login proxy: If passdb returns "source_ip" extra field, use it for outgoing connections.

Renamed network.[ch] to net.[ch]. The function prefixes already started with net_ instead of network_. And icecap wants to use network.h for other purpose. :)

SSL proxying: Remote's host never matched cert, because auth process changed it to IP. Now the "host" parameter isn't changed, but a new optional "hostip" parameter contains the IP address where to connect to.

imap/pop3/lmtp proxy: Implemented detection of proxy loops with TTL. If proxying tries to continue after 5 forward connections, it fails. The limit of 5 is hard coded currently.

login proxy: Removed host DNS lookup code, since auth does it now.

login proxy: If passdb returns proxy_refresh=<secs>, send username to proxy-notify fifo every n secs. --HG-- branch : HEAD

login: Proxying supports now doing DNS lookups for host names. --HG-- branch : HEAD

login: Proxy code API cleanup. --HG-- branch : HEAD

Handle shutdown_clients globally for all services. Delay shutting down processes until it's convenient for them, but if they're not gone in 30 seconds forcibly stop. And if that doesn't help, master will start killing them in 60 seconds. --HG-- branch : HEAD

*-login: Fixes to SSL/login proxy connection counting. --HG-- branch : HEAD

login-proxy: If proxy destination is known to be down, fail immediately. We'll use simple rules: 1. If connection to destination server failed more recently than it succeeded AND there is currently at least one client trying to connect to it, fail immediately without even trying to connect. 2. Whenever a connection to destination server fails because of timeout or some connect failure AND last successful connection to server was before our connect() started, update the "last failed" timestamp. With these rules there are no unnecessary connect() attempts or waits to servers that are down. When the server does come back up, it's noticed immediately. --HG-- branch : HEAD

login proxy: Added client_proxy passdb extra field to specify proxy's connect timeout. --HG-- branch : HEAD

*-login: Moved most of the common code to login-common. --HG-- branch : HEAD

imap/pop3 proxy: Support SSL/TLS connections to remote servers. passdb can return ssl=yes, ssl=any-cert and starttls options. --HG-- branch : HEAD

Initial commit for v2.0 master rewrite. Several features are still missing. --HG-- branch : HEAD

imap/pop3-login: Cleaned up proxying code. Don't disconnect client on proxy failures. Log proxy failures as errors. --HG-- branch : HEAD

Added more consts, ATTR_CONSTs and ATTR_PUREs. --HG-- branch : HEAD

If proxy points to the same host/port/user combination as we currently have, don't create an infinite connection loop. --HG-- branch : HEAD

Changed .h ifdef/defines to use <NAME>_H format. --HG-- branch : HEAD

Forgot to commit for the "log proxy destination" change. --HG-- branch : HEAD

Type safe callbacks weren't as easy as I thought. Only callback(void *context) can be handled generically. Others can be handled specially, but only if all the parameters are pointers, otherwise eg. int parameter can be replaced with long without compiler giving any warnings. --HG-- branch : HEAD

Added context parameter type safety checks for most callback APIs. --HG-- branch : HEAD

Fixes to login process handling, especially with login_process_per_connection=no. Removed login_max_logging_users setting since it was somewhat weird in how it worked. Added login_max_connections to replace it with login_process_per_connection=no, and with =yes its functionality is now within login_max_processes_count. --HG-- branch : HEAD

More smart IMAP and POP3 proxies. Now if remote login fails, it just destroys the proxy and allows trying another username which can go elsewhere. Also now replies with the same old "Authentication failed" error message instead of showing remote server's failure message. --HG-- branch : HEAD

Added IMAP and POP3 proxying support. --HG-- branch : HEAD