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1 \chapter{\masqmail's present and future} 1 \chapter{\masqmail's present and future}
2
3 \section{Existing features}
4 This overview regards \masqmail\ version 0.2.21, the state this document starts off.
5
6 \masqmail\ is an \MTA, therefor it accepts mail on the command line and via \SMTP. Mail queueing and alias expansion is supported. \masqmail\ is able to deliver mail to local mailboxes (in \name{mbox} or \name{maildir} format) or pass it to a \name{mail delivery agent} (like \name{procmail}). Mail destinated to remote locations is sent via \SMTP. Outgoing \SMTP\ connections feature \name{SMTP-Auth} and \name{SMTP-after-POP} authentication, but incoming \SMTP\ does not.
7
8 As \masqmail\ is focused on non-permanent Internet connections, online state can be queried by three methods: reading from a file, reading the output of a command, or by asking an \name{mserver}. Each method may return a string indicating one of the available routes being online, or returning nothing to indicate offline state.
9
10 Delivery to recipients on the local host or in local nets is done at once; delivery to recipients on the Internet is only done when being online, and queued otherwise. Each online route may have a different mail server to which mail is relayed. Return address headers are modified appropriate if wished.
11
12 Additional to the \mta\ job, \masqmail\ also offers mail retrieval services with being a \NAME{POP3} client. Thus it can fetch mail from remote locations, dependent on the active online route.
13
14
15
16 The \masqmail\ executable can be called under various names for \name{sendmail-compatibility} reasons. This is commonly organized by creating symbolic links with with different names to the \masqmail\ executable. These are \path{/usr/lib/sendmail} and \path{/usr/sbin/sendmail} because many programs expect a \mta\ to be located there. Further more \sendmail\ provides shortcuts by calling it with a different name instead of supplying command line arguments. The best known of it is \path{mailq}, which is equivilent to calling the \MTA\ with the argument \verb+-bq+. \masqmail\ reacts to the names \path{mailq}, \path{smtpd}, \path{mailrm}, \path{runq}, \path{rmail}, and \path{in.smtpd}. The last four are an addition to \sendmail. Not implemented is the name \path{newaliases} because it is not relevant to \masqmail. To provide the command nonetheless, one may write a shell script located at \path{/usr/bin/newaliases}, that simply invokes \verb+masqmail -bi+.
17
18 %masqmail: mailq, mailrm, runq, rmail, smtpd/in.smtpd
19 %sendmail: hoststat, mailq, newaliases, purgestat, smtpd
20
21 \masqmail\ is written in the \NAME{C} programming language. The program, as of version 0.2.21, consists of 34 source code and eight header files, containing about 9,000 lines of code\footnote{Measured with \name{sloccount} by David A.\ Wheeler.}. Additionally, it includes a \name{base64} implementation (about 300 lines) and \name{md5} code (about 150 lines). For systems that do not provide \name{libident}, this library is distributed as well (circa 600 lines); an available shared library however has higher precedence in linking.
22
23 The only mandatory dependency is \name{glib}---a cross-platform software utility library, originated in the \NAME{GTK+} project. It provides safer replacements for many standard library functions. (The unsafe \verb+sprintf()+ is one example.) Also it offers handy data containers, easy-to-use implementations of data structures, and much more.
24
25 With \masqmail\ comes the small tool \path{mservdetect}; it helps setting up a configuration that uses the \name{mserver} system to detect the online state. Two other binaries get compiled for testing purposes: \path{readtest} and \path{smtpsend}. All three programms use \masqmail\ source code; they only add a file with a \verb+main()+ function each.
26
27 \masqmail\ does not provide an interface for modules with additional functionality. There exists no add-on or module system. But the code is separated by function to the various source files, and some functional parts can be included or excluded by defining symbols. This means adding some argument (like \verb+--enable-maildir+) to the \verb+configure+ call. Thus the concerning code gets not removed by the preprocessor.
28
29
30
31
32
33 \section{Discussion/Ideas}
34
2 35
3 << plans to get masqmail more popular again (if that is the goal) >> %FIXME 36 << plans to get masqmail more popular again (if that is the goal) >> %FIXME
4 37
5 architecture: 38
39 \subsection{Architecture}
40
41 << architecture diagram >>
42
6 (ssl) -> msg-in (local or remote protocol handlers) -> spam-filter (and more) -> queue -> msg-out (local-delivery by MDA, or remote-protocol-handlers) -> (ssl) 43 (ssl) -> msg-in (local or remote protocol handlers) -> spam-filter (and more) -> queue -> msg-out (local-delivery by MDA, or remote-protocol-handlers) -> (ssl)
44
45 A design from scratch?
46
47 << what would be needed (effort) >> %FIXME
48
49 << would one create it at all? >> %FIXME
50
51 << should it be done? >> %FIXME
52
53
54
55 \subsection{local mail delivery}
56 But for example delivery of mail to local users is \emph{not} what \mta{}s should care about, although most \MTA\ are able to deliver mail, and many do. (\name{mail delivery agents}, like \name{procmail} and \name{maildrop}, are the right programs for this job.)
57
58
59
60 \subsection{various protocols}
61 protocols like \NAME{SMTP} and \NAME{UUCP}, between which mail is transferred.\footnote{\sendmail{}'s initial purpose was moving mail between \NAME{UUCP}, \NAME{SMTP}, and \name{Berknet}.}
62
63
64
65
7 66
8 67
9 http://fanf.livejournal.com/50917.html %how not to design an mta - the sendmail command 68 http://fanf.livejournal.com/50917.html %how not to design an mta - the sendmail command
10 http://fanf.livejournal.com/51349.html %how not to design an mta - partitioning for security 69 http://fanf.livejournal.com/51349.html %how not to design an mta - partitioning for security
11 http://fanf.livejournal.com/61132.html %how not to design an mta - local delivery 70 http://fanf.livejournal.com/61132.html %how not to design an mta - local delivery
18 77
19 78
20 79
21 << concrete decisions based on results of the last 2 chapters >> %FIXME 80 << concrete decisions based on results of the last 2 chapters >> %FIXME
22 81
23 \section{Existing features}
24 This overview regards \masqmail\ version 0.2.21, the state this document starts off.
25
26 First of all \masqmail\ is an \MTA. Therefor it accepts mail on the command line and via \SMTP. Mail queueing and alias expansion is supported. \masqmail\ is able to deliver mail to local mailboxes (in \name{mbox} or \name{maildir} format) or pass it to a \name{mail delivery agent} (like \name{procmail}). Mail destinated to remote locations is sent via \SMTP. Outgoing \SMTP\ connections feature \name{SMTP-Auth} and \name{SMTP-after-POP} authentication, but incoming \SMTP\ does not.
27
28 As \masqmail\ is focused on non-permanent Internet connections, online state can be queried by three methods: reading from a file, reading the output of a command, or by asking an \name{mserver}. Each method may return a string indicating one of the available routes being online, or returning nothing to indicate offline state.
29
30 Delivery to recipients on the local host or in local nets is done at once; delivery to recipients on the Internet is only done when being online, and queued otherwise. Each online route may have a different mail server to which mail is relayed. Return address headers are modified appropriate if wished.
31
32 Additional to the \mta\ job, \masqmail\ also offers mail retrieval services with being a \NAME{POP3} client. Thus it can fetch mail from remote locations, dependent on the active online route.
33 82
34 83
35 \subsubsection*{masqmail stuff}
36 84
37 The \masqmail\ executable can be called under various names for \name{sendmail-compatibility} reasons. This is commonly organized by creating symbolic links with with different names to the \masqmail\ executable. These are \path{/usr/lib/sendmail} and \path{/usr/sbin/sendmail} because many programs expect a \mta\ to be located there. Further more \sendmail\ provides shortcuts by calling it with a different name instead of supplying command line arguments. The best known of it is \path{mailq}, which is equivilent to calling the \MTA\ with the argument \verb+-bq+. \masqmail\ reacts to the names \path{mailq}, \path{smtpd}, \path{mailrm}, \path{runq}, \path{rmail}, and \path{in.smtpd}. The last four are an addition to \sendmail. Not implemented is the name \path{newaliases} because it is not relevant to \masqmail. To provide the command nonetheless, one may write a shell script located at \path{/usr/bin/newaliases}, that simply invokes \verb+masqmail -bi+.
38
39 %masqmail: mailq, mailrm, runq, rmail, smtpd/in.smtpd
40 %sendmail: hoststat, mailq, newaliases, purgestat, smtpd
41
42 \masqmail\ is written in the \NAME{C} programming language. The program, as of version 0.2.21, consists of 34 source code and eight header files, containing about 9,000 lines of code\footnote{Measured with \name{sloccount} by David A.\ Wheeler.}. Additionally, it includes a \name{base64} implementation (about 300 lines) and \name{md5} code (about 150 lines). For systems that do not provide \name{libident}, this library is distributed as well (circa 600 lines); an available shared library however has higher precedence in linking.
43
44 The only mandatory dependency is \name{glib}---a cross-platform software utility library, originated in the \NAME{GTK+} project. It provides safer replacements for many standard library functions. (The unsafe \verb+sprintf()+ is one example.) Also it offers handy data containers, easy-to-use implementations of data structures, and much more.
45
46 With \masqmail\ comes the small tool \path{mservdetect}; it helps setting up a configuration that uses the \name{mserver} system to detect the online state. Two other binaries get compiled for testing purposes: \path{readtest} and \path{smtpsend}. All three programms use \masqmail\ source code; they only add a file with a \verb+main()+ function each.
47
48 \masqmail\ does not provide an interface for modules with additional functionality. There exists no add-on or module system. But the code is separated by function to the various source files, and some functional parts can be included or excluded by defining symbols. This means adding some argument (like \verb+--enable-maildir+) to the \verb+configure+ call. Thus the concerning code gets not removed by the preprocessor.
49 85
50 86
51 \section{Directions to go} 87 \section{Directions to go}
52 88
53 \subsection{\masqmail\ in five years} 89 \subsection{\masqmail\ in five years}
65 << difference for free software >> %FIXME 101 << difference for free software >> %FIXME
66 102
67 << why is it worth to revive masqmail? >> %FIXME 103 << why is it worth to revive masqmail? >> %FIXME
68 104
69 105
70 \subsection{A design from scratch}
71 106
72 << what would be needed (effort) >> %FIXME
73
74 << would one create it at all? >> %FIXME
75
76 << should it be done? >> %FIXME
77 107
78 108
79 109
80 \section{Work to do} 110 \section{Work to do}
81 111