diff options
| -rw-r--r-- | .gitignore | 1 | ||||
| -rw-r--r-- | LICENSE | 122 | ||||
| -rw-r--r-- | config.go | 8 | ||||
| -rw-r--r-- | go.mod | 5 | ||||
| -rw-r--r-- | go.sum | 2 | ||||
| -rw-r--r-- | maild.scfg | 1 | ||||
| -rw-r--r-- | main.go | 196 |
7 files changed, 335 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..9820ee6 --- /dev/null +++ b/.gitignore @@ -0,0 +1 @@ +/maild @@ -0,0 +1,122 @@ +Creative Commons Legal Code + +CC0 1.0 Universal + + CREATIVE COMMONS CORPORATION IS NOT A LAW FIRM AND DOES NOT PROVIDE + LEGAL SERVICES. DISTRIBUTION OF THIS DOCUMENT DOES NOT CREATE AN + ATTORNEY-CLIENT RELATIONSHIP. CREATIVE COMMONS PROVIDES THIS + INFORMATION ON AN "AS-IS" BASIS. CREATIVE COMMONS MAKES NO WARRANTIES + REGARDING THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS + PROVIDED HEREUNDER, AND DISCLAIMS LIABILITY FOR DAMAGES RESULTING FROM + THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS PROVIDED + HEREUNDER. + +Statement of Purpose + +The laws of most jurisdictions throughout the world automatically confer +exclusive Copyright and Related Rights (defined below) upon the creator +and subsequent owner(s) (each and all, an "owner") of an original work of +authorship and/or a database (each, a "Work"). + +Certain owners wish to permanently relinquish those rights to a Work for +the purpose of contributing to a commons of creative, cultural and +scientific works ("Commons") that the public can reliably and without fear +of later claims of infringement build upon, modify, incorporate in other +works, reuse and redistribute as freely as possible in any form whatsoever +and for any purposes, including without limitation commercial purposes. +These owners may contribute to the Commons to promote the ideal of a free +culture and the further production of creative, cultural and scientific +works, or to gain reputation or greater distribution for their Work in +part through the use and efforts of others. + +For these and/or other purposes and motivations, and without any +expectation of additional consideration or compensation, the person +associating CC0 with a Work (the "Affirmer"), to the extent that he or she +is an owner of Copyright and Related Rights in the Work, voluntarily +elects to apply CC0 to the Work and publicly distribute the Work under its +terms, with knowledge of his or her Copyright and Related Rights in the +Work and the meaning and intended legal effect of CC0 on those rights. + +1. Copyright and Related Rights. A Work made available under CC0 may be +protected by copyright and related or neighboring rights ("Copyright and +Related Rights"). Copyright and Related Rights include, but are not +limited to, the following: + + i. the right to reproduce, adapt, distribute, perform, display, + communicate, and translate a Work; + ii. moral rights retained by the original author(s) and/or performer(s); +iii. publicity and privacy rights pertaining to a person's image or + likeness depicted in a Work; + iv. rights protecting against unfair competition in regards to a Work, + subject to the limitations in paragraph 4(a), below; + v. rights protecting the extraction, dissemination, use and reuse of data + in a Work; + vi. database rights (such as those arising under Directive 96/9/EC of the + European Parliament and of the Council of 11 March 1996 on the legal + protection of databases, and under any national implementation + thereof, including any amended or successor version of such + directive); and +vii. other similar, equivalent or corresponding rights throughout the + world based on applicable law or treaty, and any national + implementations thereof. + +2. Waiver. To the greatest extent permitted by, but not in contravention +of, applicable law, Affirmer hereby overtly, fully, permanently, +irrevocably and unconditionally waives, abandons, and surrenders all of +Affirmer's Copyright and Related Rights and associated claims and causes +of action, whether now known or unknown (including existing as well as +future claims and causes of action), in the Work (i) in all territories +worldwide, (ii) for the maximum duration provided by applicable law or +treaty (including future time extensions), (iii) in any current or future +medium and for any number of copies, and (iv) for any purpose whatsoever, +including without limitation commercial, advertising or promotional +purposes (the "Waiver"). Affirmer makes the Waiver for the benefit of each +member of the public at large and to the detriment of Affirmer's heirs and +successors, fully intending that such Waiver shall not be subject to +revocation, rescission, cancellation, termination, or any other legal or +equitable action to disrupt the quiet enjoyment of the Work by the public +as contemplated by Affirmer's express Statement of Purpose. + +3. Public License Fallback. Should any part of the Waiver for any reason +be judged legally invalid or ineffective under applicable law, then the +Waiver shall be preserved to the maximum extent permitted taking into +account Affirmer's express Statement of Purpose. In addition, to the +extent the Waiver is so judged Affirmer hereby grants to each affected +person a royalty-free, non transferable, non sublicensable, non exclusive, +irrevocable and unconditional license to exercise Affirmer's Copyright and +Related Rights in the Work (i) in all territories worldwide, (ii) for the +maximum duration provided by applicable law or treaty (including future +time extensions), (iii) in any current or future medium and for any number +of copies, and (iv) for any purpose whatsoever, including without +limitation commercial, advertising or promotional purposes (the +"License"). The License shall be deemed effective as of the date CC0 was +applied by Affirmer to the Work. Should any part of the License for any +reason be judged legally invalid or ineffective under applicable law, such +partial invalidity or ineffectiveness shall not invalidate the remainder +of the License, and in such case Affirmer hereby affirms that he or she +will not (i) exercise any of his or her remaining Copyright and Related +Rights in the Work or (ii) assert any associated claims and causes of +action with respect to the Work, in either case contrary to Affirmer's +express Statement of Purpose. + +4. Limitations and Disclaimers. + + a. No trademark or patent rights held by Affirmer are waived, abandoned, + surrendered, licensed or otherwise affected by this document. + b. Affirmer offers the Work as-is and makes no representations or + warranties of any kind concerning the Work, express, implied, + statutory or otherwise, including without limitation warranties of + title, merchantability, fitness for a particular purpose, non + infringement, or the absence of latent or other defects, accuracy, or + the present or absence of errors, whether or not discoverable, all to + the greatest extent permissible under applicable law. + c. Affirmer disclaims responsibility for clearing rights of other persons + that may apply to the Work or any use thereof, including without + limitation any person's Copyright and Related Rights in the Work. + Further, Affirmer disclaims responsibility for obtaining any necessary + consents, permissions or other rights required for any use of the + Work. + d. Affirmer understands and acknowledges that Creative Commons is not a + party to this document and has no duty or obligation with respect to + this CC0 or use of the Work. + diff --git a/config.go b/config.go new file mode 100644 index 0000000..5641af2 --- /dev/null +++ b/config.go @@ -0,0 +1,8 @@ +// TODO: edit scfg to require fields to exist unless explicitly +// +// marked optional. +package main + +var config struct { + Server_name string `scfg:"server_name"` +} @@ -0,0 +1,5 @@ +module go.lindenii.runxiyu.org/maild + +go 1.23.4 + +require go.lindenii.runxiyu.org/lindenii-common v0.0.0-20241229193139-603ef6227aca @@ -0,0 +1,2 @@ +go.lindenii.runxiyu.org/lindenii-common v0.0.0-20241229193139-603ef6227aca h1:iyxIKtyBNe5RlIMVu+whX2r2JGK9JCo6RotHrHstb0U= +go.lindenii.runxiyu.org/lindenii-common v0.0.0-20241229193139-603ef6227aca/go.mod h1:bOxuuGXA3UpbLb1lKohr2j2MVcGGLcqfAprGx9VCkMA= diff --git a/maild.scfg b/maild.scfg new file mode 100644 index 0000000..24f7b84 --- /dev/null +++ b/maild.scfg @@ -0,0 +1 @@ +server_name mail.andrewyu.org @@ -0,0 +1,196 @@ +package main + +// TODO: panic bleh!!!!!!!!!!!!!!!!!! + +import ( + "bufio" + "bytes" + "net" + "os" + "slices" + "strings" + + "go.lindenii.runxiyu.org/lindenii-common/clog" + "go.lindenii.runxiyu.org/lindenii-common/scfg" +) + +const VERSION = "lindenii-maild v0.0.0" + +func main() { + config_file, err := os.Open("maild.scfg") + if err != nil { + panic(err) + } + + err = scfg.NewDecoder(bufio.NewReader(config_file)).Decode(&config) + if err != nil { + panic(err) + } + + listener, err := net.Listen("tcp", ":25") + if err != nil { + panic(err) + } + defer listener.Close() + + for { + conn, err := listener.Accept() + if err != nil { + panic(err) + } + + go func() { + err := handle_connection(bufio.NewReader(conn), bufio.NewWriter(conn)) + if err != nil { + clog.Error("connection handler returned error", "err", err) + } + }() + } + +} + +type server_state_t uint + +const ( + server_state_begin server_state_t = iota + server_state_helo + server_state_mail + server_state_rcpt +) + +func handle_connection(reader *bufio.Reader, writer *bufio.Writer) error { + _, _ = writer.WriteString("220 " + config.Server_name + " " + VERSION + "\r\n") + _ = writer.Flush() + server_state := server_state_begin + var remote_server_name string + var current_mail_from string + var current_rcpt_to []string + for { + line, err := reader.ReadString('\n') + if err != nil { + return err + } + line = strings.TrimSuffix(line, "\n") + line = strings.TrimSuffix(line, "\r") + cmd_end := strings.IndexByte(line, ' ') + var param_start int + if cmd_end == -1 { + cmd_end = len(line) + param_start = len(line) + } else { + param_start = cmd_end + 1 + } + cmd := strings.ToUpper(line[:cmd_end]) + param := line[param_start:] + switch_cmd: + switch cmd { + case "HELO": + if param == "" { // TODO: actually validate the hostname + _, _ = writer.WriteString("501 Syntax: HELO hostname\r\n") + _ = writer.Flush() + break + } + remote_server_name = param + _ = remote_server_name // TODO + server_state = server_state_helo + _, _ = writer.WriteString("250 " + config.Server_name + "\r\n") + _ = writer.Flush() + case "MAIL": + switch server_state { + case server_state_begin: + _, _ = writer.WriteString("503 5.5.1 Error: send HELO/EHLO first\r\n") + _ = writer.Flush() + break switch_cmd + case server_state_helo: + break + case server_state_mail: + _, _ = writer.WriteString("503 5.5.1 Error: nested MAIL command\r\n") + _ = writer.Flush() + break switch_cmd + } + if len(param) <= len("FROM:") || strings.ToUpper(param[:len("FROM:")]) != "FROM:" { + _, _ = writer.WriteString("501 5.5.4 Syntax: MAIL FROM:<address>\r\n") + _ = writer.Flush() + break + } + current_mail_from = param[len("FROM:"):] + current_rcpt_to = []string{} + server_state = server_state_mail + _, _ = writer.WriteString("250 2.1.0 Ok\r\n") + _ = writer.Flush() + // TODO: Address validation + case "RCPT": + if server_state != server_state_mail && server_state != server_state_rcpt { + _, _ = writer.WriteString("503 5.5.1 Error: need MAIL command\r\n") + _ = writer.Flush() + break + } + if len(param) <= len("TO:") || strings.ToUpper(param[:len("TO:")]) != "TO:" { + _, _ = writer.WriteString("501 5.5.4 Syntax: RCPT TO:<address>\r\n") + _ = writer.Flush() + break + } + current_rcpt_to = append(current_rcpt_to, param[len("TO:"):]) + server_state = server_state_rcpt + _, _ = writer.WriteString("250 2.1.5 Ok\r\n") + _ = writer.Flush() + case "DATA": + if server_state != server_state_rcpt { + _, _ = writer.WriteString("503 5.5.1 Error: need RCPT command\r\n") + _ = writer.Flush() + break + } + _, _ = writer.WriteString("354 End data with <CR><LF>.<CR><LF>\r\n") + _ = writer.Flush() + var current_data []byte + for { + tmp, err := reader.ReadSlice('\r') + if err != nil { + return err + } + + // reader.ReadSlice returns an internal buffer that gets + // overwritten on the next reader operation. So we must + // make a copy; also we have to allocate data_part to + // the correct length because [[builtin.copy]] copies + // min(len(dst), len(src)) items. + data_part := make([]byte, len(tmp)) + copy(data_part, tmp) + + clog.Debug("e", "e", string(data_part)) + next_four, err := reader.Peek(4) + if err != nil { + return err + } + if bytes.Equal(next_four, []byte{'\n', '.', '\r', '\n'}) { + current_data = slices.Concat(current_data, data_part[:len(data_part)-1]) + clog.Debug("eee", string(next_four)) // shut up go + break + } + clog.Debug("pre concat", "current_data", string(current_data), "data_part", string(data_part)) + current_data = slices.Concat(current_data, data_part) + clog.Debug("post concat", "current_data", string(current_data), "data_part", string(data_part)) + } + _, err := reader.Discard(4) + if err != nil { + return err + } + deliver_incoming(current_mail_from, current_rcpt_to, current_data) + server_state = server_state_helo + _, _ = writer.WriteString("250 2.0.0 Ok: Accepted\r\n") + _ = writer.Flush() + default: + _, _ = writer.WriteString("500 5.5.2 Error: command not recognized\r\n") + _ = writer.Flush() + } + } +} + +func deliver_incoming(envelope_from string, envelope_recipients []string, data []byte) { + clog.Debug( + "incoming_mail", + "envelope_from", envelope_from, + "envelope_recipients", envelope_recipients, + "data", string(data), + ) +} |