From 8c18330aa3976aa981bbe4f135960a92b5923fb6 Mon Sep 17 00:00:00 2001 From: Runxi Yu Date: Sat, 7 Dec 2024 21:13:28 +0800 Subject: Initial commit --- .gitignore | 1 + LICENSE.CC0 | 124 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ LICENSE.MIT | 16 ++++++++ README.md | 3 ++ const.go | 7 ++++ errors.go | 13 +++++++ go.mod | 3 ++ main.go | 53 ++++++++++++++++++++++++++ msg.go | 125 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ tags.go | 119 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ util.go | 8 ++++ 11 files changed, 472 insertions(+) create mode 100644 .gitignore create mode 100644 LICENSE.CC0 create mode 100644 LICENSE.MIT create mode 100644 README.md create mode 100644 const.go create mode 100644 errors.go create mode 100644 go.mod create mode 100644 main.go create mode 100644 msg.go create mode 100644 tags.go create mode 100644 util.go diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..fc08677 --- /dev/null +++ b/.gitignore @@ -0,0 +1 @@ +/meseircd diff --git a/LICENSE.CC0 b/LICENSE.CC0 new file mode 100644 index 0000000..7c5febc --- /dev/null +++ b/LICENSE.CC0 @@ -0,0 +1,124 @@ +This license applies to code written for the MeseIRCd project. + +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. 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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/LICENSE.MIT b/LICENSE.MIT new file mode 100644 index 0000000..6c8954c --- /dev/null +++ b/LICENSE.MIT @@ -0,0 +1,16 @@ +This license applies to code copied from Ergo IRCd. + +Copyright (c) 2016-2021 Daniel Oaks +Copyright (c) 2018-2021 Shivaram Lingamneni + +Permission to use, copy, modify, and/or distribute this software for any +purpose with or without fee is hereby granted, provided that the above +copyright notice and this permission notice appear in all copies. + +THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH +REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND +FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, +INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM +LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR +OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR +PERFORMANCE OF THIS SOFTWARE. diff --git a/README.md b/README.md new file mode 100644 index 0000000..551a422 --- /dev/null +++ b/README.md @@ -0,0 +1,3 @@ +# MeseIRCd + +A primitive internet relay chat daemon. diff --git a/const.go b/const.go new file mode 100644 index 0000000..962db26 --- /dev/null +++ b/const.go @@ -0,0 +1,7 @@ +package main + +const ( + MaxlenTags = 8191 + MaxlenTagData = MaxlenTags - 2 + MaxlenBody = 510 +) diff --git a/errors.go b/errors.go new file mode 100644 index 0000000..2d4ed02 --- /dev/null +++ b/errors.go @@ -0,0 +1,13 @@ +package main + +import ( + "errors" +) + +var ( + ErrEmptyMessage = errors.New("empty message") + ErrIllegalByte = errors.New("illegal byte") + ErrTagsTooLong = errors.New("tags too long") + ErrInvalidTagContent = errors.New("invalid tag content") + ErrBodyTooLong = errors.New("body too long") +) diff --git a/go.mod b/go.mod new file mode 100644 index 0000000..5447113 --- /dev/null +++ b/go.mod @@ -0,0 +1,3 @@ +module git.sr.ht/~runxiyu/meseircd + +go 1.23.3 diff --git a/main.go b/main.go new file mode 100644 index 0000000..0898bd5 --- /dev/null +++ b/main.go @@ -0,0 +1,53 @@ +package main + +import ( + "bufio" + "log" + "log/slog" + "net" +) + +type Client struct { + conn net.Conn +} + +func main() { + listener, err := net.Listen("tcp", ":6667") + if err != nil { + log.Fatal(err) + } + defer listener.Close() + + for { + conn, err := listener.Accept() + if err != nil { + log.Fatal(err) + } + + client := &Client{ + conn: conn, + } + go func() { + defer func() { + raised := recover() + if raised != nil { + slog.Error("connection routine panicked", "raised", raised) + } + }() + client.handleConnection() + }() + } +} + +func (client *Client) handleConnection() { + reader := bufio.NewReader(client.conn) + for { + line, err := reader.ReadString('\n') + if err != nil { + slog.Error("error while reading from connection", "error", err) + client.conn.Close() + return + } + _, _ = parseIRCMsg(line) + } +} diff --git a/msg.go b/msg.go new file mode 100644 index 0000000..ff4b3a4 --- /dev/null +++ b/msg.go @@ -0,0 +1,125 @@ +package main + +import ( + "strings" +) + +type Msg struct { + RawMessage string + RawSource string + Command string + Tags map[string]string + Params []string +} + +// Partially adapted from https://github.com/ergochat/irc-go.git +func parseIRCMsg(line string) (msg Msg, err error) { + msg = Msg{ + RawMessage: line, + } + + line = strings.TrimSuffix(line, "\n") + line = strings.TrimSuffix(line, "\r") + + if len(line) == 0 { + err = ErrEmptyMessage + return + } + + for _, v := range line { + if v == '\x00' || v == '\r' || v == '\n' { + err = ErrIllegalByte + return + } + } + + // IRCv3 tags + if line[0] == '@' { + tagEnd := strings.IndexByte(line, ' ') + if tagEnd == -1 { + err = ErrEmptyMessage + return + } + tagsString := line[1:tagEnd] + if 0 < MaxlenTagData && MaxlenTagData < len(tagsString) { + err = ErrTagsTooLong + return + } + msg.Tags, err = parseTags(tagsString) + if err != nil { + return + } + // Skip over the tags and the separating space + line = line[tagEnd+1:] + } + + if len(line) > MaxlenBody { + err = ErrBodyTooLong + line = line[:MaxlenBody] + } + + line = trimInitialSpaces(line) + + // Source + if 0 < len(line) && line[0] == ':' { + sourceEnd := strings.IndexByte(line, ' ') + if sourceEnd == -1 { + err = ErrEmptyMessage + return + } + msg.RawSource = line[1:sourceEnd] + // Skip over the source and the separating space + line = line[sourceEnd+1:] + } + + // Command + commandEnd := strings.IndexByte(line, ' ') + paramStart := commandEnd + 1 + if commandEnd == -1 { + commandEnd = len(line) + paramStart = len(line) + } + baseCommand := line[:commandEnd] + if len(baseCommand) == 0 { + err = ErrEmptyMessage + return + } + // TODO: Actually must be either letters or a 3-digit numeric + if !isASCII(baseCommand) { + err = ErrIllegalByte + return + } + msg.Command = strings.ToUpper(baseCommand) + line = line[paramStart:] + + // Other arguments + for { + line = trimInitialSpaces(line) + if len(line) == 0 { + break + } + // Trailing + if line[0] == ':' { + msg.Params = append(msg.Params, line[1:]) + break + } + paramEnd := strings.IndexByte(line, ' ') + if paramEnd == -1 { + msg.Params = append(msg.Params, line) + break + } + msg.Params = append(msg.Params, line[:paramEnd]) + line = line[paramEnd+1:] + } + + return +} + +func isASCII(str string) bool { + for i := 0; i < len(str); i++ { + if str[i] > 127 { + return false + } + } + return true +} diff --git a/tags.go b/tags.go new file mode 100644 index 0000000..43a2833 --- /dev/null +++ b/tags.go @@ -0,0 +1,119 @@ +// Almost everything in this file is adapted from Ergo IRCd +// This is probably considered a derived work for copyright purposes +// +// SPDX-License-Identifier: MIT + +package main + +import ( + "strings" + "unicode/utf8" +) + +func parseTags(tagsString string) (tags map[string]string, err error) { + tags = make(map[string]string) + for 0 < len(tagsString) { + tagEnd := strings.IndexByte(tagsString, ';') + endPos := tagEnd + nextPos := tagEnd + 1 + if tagEnd == -1 { + endPos = len(tagsString) + nextPos = len(tagsString) + } + tagPair := tagsString[:endPos] + equalsIndex := strings.IndexByte(tagPair, '=') + var tagName, tagValue string + if equalsIndex == -1 { + // Tag with no value + tagName = tagPair + } else { + tagName, tagValue = tagPair[:equalsIndex], tagPair[equalsIndex+1:] + } + // "Implementations [...] MUST NOT perform any validation that would + // reject the message if an invalid tag key name is used." + if validateTagName(tagName) { + if !validateTagValue(tagValue) { + err = ErrInvalidTagContent + return + } + tags[tagName] = UnescapeTagValue(tagValue) + } + tagsString = tagsString[nextPos:] + } + return +} + +func UnescapeTagValue(inString string) string { + // buf.Len() == 0 is the fastpath where we have not needed to unescape any chars + var buf strings.Builder + remainder := inString + for { + backslashPos := strings.IndexByte(remainder, '\\') + + if backslashPos == -1 { + if buf.Len() == 0 { + return inString + } else { + buf.WriteString(remainder) + break + } + } else if backslashPos == len(remainder)-1 { + // trailing backslash, which we strip + if buf.Len() == 0 { + return inString[:len(inString)-1] + } else { + buf.WriteString(remainder[:len(remainder)-1]) + break + } + } + + // Non-trailing backslash detected; we're now on the slowpath + // where we modify the string + if buf.Len() < len(inString) { + buf.Grow(len(inString)) + } + buf.WriteString(remainder[:backslashPos]) + buf.WriteByte(escapedCharLookupTable[remainder[backslashPos+1]]) + remainder = remainder[backslashPos+2:] + } + + return buf.String() +} + +var escapedCharLookupTable [256]byte + +func init() { + for i := 0; i < 256; i += 1 { + escapedCharLookupTable[i] = byte(i) + } + escapedCharLookupTable[':'] = ';' + escapedCharLookupTable['s'] = ' ' + escapedCharLookupTable['r'] = '\r' + escapedCharLookupTable['n'] = '\n' +} + +// https://ircv3.net/specs/extensions/message-tags.html#rules-for-naming-message-tags +func validateTagName(name string) bool { + if len(name) == 0 { + return false + } + if name[0] == '+' { + name = name[1:] + } + if len(name) == 0 { + return false + } + // Let's err on the side of leniency here; allow -./ (45-47) in any position + for i := 0; i < len(name); i++ { + c := name[i] + if !(('-' <= c && c <= '/') || ('0' <= c && c <= '9') || ('A' <= c && c <= 'Z') || ('a' <= c && c <= 'z')) { + return false + } + } + return true +} + +// "Tag values MUST be encoded as UTF8." +func validateTagValue(value string) bool { + return utf8.ValidString(value) +} diff --git a/util.go b/util.go new file mode 100644 index 0000000..0037330 --- /dev/null +++ b/util.go @@ -0,0 +1,8 @@ +package main + +func trimInitialSpaces(line string) string { + var i int + for i = 0; i < len(line) && line[i] == ' '; i++ { + } + return line[i:] +} -- cgit v1.2.3