lmtp: Ported to use lib-smtp/server. Implicitly fixes handling of multi-line replies from proxy backend. Implicitly adds support for mixing local and proxy recipients. Implicitly adds support for SMTP CHUNKING. RCPT failures are reported back to the client immediately, rather than waiting for the DATA command.

lmtp: proxy: Restructured proxy so that it has direct access to struct client. This avoids the hassle of initializing using struct lmtp_proxy_settings and uselessly reallocating stuff that is already persisted in struct client. Moved the proxy from alloconly pool to default pool in the process. The amount of allocated stuff will diminish further in subsequent commits.

lmtp: proxy: Made struct lmtp_proxy_rcpt_settings private.

lmtp: proxy: Merged lmtp_proxy_add_rcpt() into lmtp_proxy_rcpt().

lmtp: proxy: Made lmtp_proxy_mail_from() private.

lmtp: proxy: Made lmtp_proxy_init() private.

lmtp: Split off local delivery in a struct separate from the client. This mimics proxy delivery, making the implementation better structured.

lmtp: proxy: Changed return type of lmtp_proxy_rcpt() from bool to int.

lmtp: proxy: Renamed client_proxy_rcpt() to lmtp_proxy_rcpt().

lmtp: proxy: Removed dns_client_socket_path from struct lmtp_proxy_settings. It is globally accessible.

lmtp: Moved code relating to proxy from commands.c to lmtp-proxy.c.

lmtp: proxy: Changed implemention to use lib-smtp/smtp-client.

lmtp proxy: Avoid DNS lookup for "host" if passdb also returns "hostip"

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.

lmtp: Added support for DSN ORCPT parameter. If the parameter is specified, it's used as the original recipient address in Sieve. The ORCPT parameter is also proxied to destination LMTP server if used (without checking if it supports it). We don't currently advertise DSN extension, so this feature won't be enabled automatically.

lmtp: Removed some unnecessary code

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. :)

lmtp proxy: Include session ID string in timeout reply text.

Marked functions parameters that are allowed to be NULL. Some APIs were also changed. The non-obvious APIs where NULL parameter was changed to "" are master_service_init() and auth_master_user_list_init(). These checks can currently be enabled only on a patched clang: http://llvm.org/bugs/show_bug.cgi?id=6786

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.

lmtp proxy: Send client's IP/port to destination server via XCLIENT if possible.

lmtp: Simplify LMTP proxying by first reading the whole input to memory/disk. This hopefully fixes problems related to LMTP proxying, at the cost of having to write large mails to temp directory.

lmtp proxy: Added support for DNS lookups. --HG-- branch : HEAD

lmtp proxy: More error handling fixes. --HG-- branch : HEAD

lmtp proxy: Add Received: header. --HG-- branch : HEAD

lmtp client, proxy: Several bugfixes. --HG-- branch : HEAD

lmtp: Added initial support for proxying mails to other LMTP/SMTP servers. --HG-- branch : HEAD