An Efficient Linux Kernel Implementation of Service Function
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Improving Route Scalability: Nexthops As Separate Objects
Improving Route Scalability: Nexthops as Separate Objects September 2019 David Ahern | Cumulus Networks !1 Agenda Executive Summary ▪ If you remember nothing else about this talk … Driving use case Review legacy route API Dive into Nexthop API Benefits of the new API Cumulus Networks !2 Performance with the Legacy Route API route route route prefix/lenroute prefix/lendev prefix/lendev gatewayprefix/len gatewaydev gatewaydev gateway Cumulus Networks !3 Splitting Next Hops from Routes Routes with separate Nexthop objects Legacy Route API route route prefix/len nexthop route nexthop id dev route gateway prefix/lenroute prefix/lendev prefix/lendev gatewayprefix/len gatewaydev gatewaydev gateway route prefix/len nexthop nexthop nexthop id group nexthopdev nexthop[N] gatewaydev gateway Cumulus Networks !4 Dramatically Improves Route Scalability … Cumulus Networks !5 … with the Potential for Constant Insert Times Cumulus Networks !6 Networking Operating System Using Linux APIs Routing daemon or utility manages switchd ip FRR entries in kernel FIBs via rtnetlink APIs SDK userspace ▪ Enables other control plane software to use Linux networking APIs rtnetlink Data path connections, stats, troubleshooting, … FIB notifications FIB Management of hardware offload is separate kernel upper devices tunnels ▪ Keeps hardware in sync with kernel ... eth0 swp1 swp2 swpN Userspace driver with SDK leveraging driver driver driver kernel notifications NIC switch ASIC H / W Cumulus Networks !7 NOS with switchdev Driver In-kernel switchdev driver ip FRR Leverages -
Chapter 3. Booting Operating Systems
Chapter 3. Booting Operating Systems Abstract: Chapter 3 provides a complete coverage on operating systems booting. It explains the booting principle and the booting sequence of various kinds of bootable devices. These include booting from floppy disk, hard disk, CDROM and USB drives. Instead of writing a customized booter to boot up only MTX, it shows how to develop booter programs to boot up real operating systems, such as Linux, from a variety of bootable devices. In particular, it shows how to boot up generic Linux bzImage kernels with initial ramdisk support. It is shown that the hard disk and CDROM booters developed in this book are comparable to GRUB and isolinux in performance. In addition, it demonstrates the booter programs by sample systems. 3.1. Booting Booting, which is short for bootstrap, refers to the process of loading an operating system image into computer memory and starting up the operating system. As such, it is the first step to run an operating system. Despite its importance and widespread interests among computer users, the subject of booting is rarely discussed in operating system books. Information on booting are usually scattered and, in most cases, incomplete. A systematic treatment of the booting process has been lacking. The purpose of this chapter is to try to fill this void. In this chapter, we shall discuss the booting principle and show how to write booter programs to boot up real operating systems. As one might expect, the booting process is highly machine dependent. To be more specific, we shall only consider the booting process of Intel x86 based PCs. -
Mesalock Linux: Towards a Memory-Safe Linux Distribution
MesaLock Linux Towards a memory-safe Linux distribution Mingshen Sun MesaLock Linux Maintainer | Baidu X-Lab, USA Shanghai Jiao Tong University, 2018 whoami • Senior Security Research in Baidu X-Lab, Baidu USA • PhD, The Chinese University of Hong Kong • System security, mobile security, IoT security, and car hacking • MesaLock Linux, TaintART, Pass for iOS, etc. • mssun @ GitHub | https://mssun.me !2 MesaLock Linux • Why • What • How !3 Why • Memory corruption occurs in a computer program when the contents of a memory location are unintentionally modified; this is termed violating memory safety. • Memory safety is the state of being protected from various software bugs and security vulnerabilities when dealing with memory access, such as buffer overflows and dangling pointers. !4 Stack Buffer Overflow • https://youtu.be/T03idxny9jE !5 Types of memory errors • Access errors • Buffer overflow • Race condition • Use after free • Uninitialized variables • Memory leak • Double free !6 Memory-safety in user space • CVE-2017-13089 wget: Stack-based buffer overflow in HTTP protocol handling • A stack-based buffer overflow when processing chunked, encoded HTTP responses was found in wget. By tricking an unsuspecting user into connecting to a malicious HTTP server, an attacker could exploit this flaw to potentially execute arbitrary code. • https://bugzilla.redhat.com/show_bug.cgi?id=1505444 • POC: https://github.com/r1b/CVE-2017-13089 !7 What • Linux distribution • Memory-safe user space !8 Linux Distribution • A Linux distribution (often abbreviated as distro) is an operating system made from a software collection, which is based upon the Linux kernel and, often, a package management system. !9 Linux Distros • Server: CentOS, Federa, RedHat, Debian • Desktop: Ubuntu • Mobile: Android • Embedded: OpenWRT, Yocto • Hard-core: Arch Linux, Gentoo • Misc: ChromeOS, Alpine Linux !10 Security and Safety? • Gentoo Hardened: enables several risk-mitigating options in the toolchain, supports PaX, grSecurity, SELinux, TPE and more. -
Openswitch OPX Configuration Guide Release 3.0.0 2018 - 9
OpenSwitch OPX Configuration Guide Release 3.0.0 2018 - 9 Rev. A02 Contents 1 Network configuration....................................................................................................................................4 2 Interfaces...................................................................................................................................................... 5 Physical ports..................................................................................................................................................................... 5 Fan-out interfaces..............................................................................................................................................................6 Port-channel and bond interfaces....................................................................................................................................7 VLAN interfaces................................................................................................................................................................. 7 Port profiles.........................................................................................................................................................................8 3 Layer 2 bridging............................................................................................................................................10 VLAN bridging...................................................................................................................................................................10 -
Adecuándose a La Norma ISO/IEC 1799 Mediante Software Libre
Adecu´andose a la norma ISO/IEC 1799 mediante software libre * Jose Fernando Carvajal Vi´on Grupo de Inter´esen Seguridad de ATI (ATI-GISI) <[email protected]> Javier Fern´andez-Sanguino Pe˜na Grupo de Inter´esen Seguridad de ATI (ATI-GISI) <[email protected]> 28 de octubre de 2002 Resumen Este art´ıculo muestra la forma de adecuar a la norma ISO/IEC 17999 un sistema de informaci´onimplementado en un servidor cuyo software de sistema operativo se basa en alguna alternativa de software Libre y c´odigo abierto. La utilizaci´onde una distribuci´onDebian GNU/Linux sirve como base a la que a˜nadir las utilidades y paquetes necesarios para conseguir el objetivo. ´Indice 1. Introducci´on 1 2. Objetivo y Asunciones 2 3. Cumplimiento de la Norma ISO/IEC 17799 en GNU/Linux 4 4. Conclusiones 4 5. Referencias 5 6. Referencias de herramientas 7 7. Referencias Generales 11 *Copyright (c) 2002 Jose Fernando Carvajal y Javier Fern´andez-Sanguino. Se otorga permiso para copiar, distribuir y/o modificar este documento bajo los t´erminos de la Licencia de Documen- taci´onLibre GNU, Versi´on1.1 o cualquier otra versi´onposterior publicada por la Free Software Foundation. Puede consultar una copia de la licencia en: http://www.gnu.org/copyleft/fdl.html 1 1. Introducci´on De forma general para mantener la seguridad de los activos de informaci´on se deben preservar las caracter´ısticas siguientes [1]. 1. Confidencialidad: s´oloel personal o equipos autorizados pueden acceder a la informaci´on. 2. Integridad: la informaci´on y sus m´etodos de proceso son exactos y completos. -
Devt: Let the Device Talk
Iowa State University Capstones, Theses and Creative Components Dissertations Summer 2020 DevT: Let the Device Talk Chander Bhushan Gupta Follow this and additional works at: https://lib.dr.iastate.edu/creativecomponents Part of the Data Storage Systems Commons Recommended Citation Gupta, Chander Bhushan, "DevT: Let the Device Talk" (2020). Creative Components. 585. https://lib.dr.iastate.edu/creativecomponents/585 This Creative Component is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Creative Components by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. DevT: Let the Device Talk by Chander Bhushan Gupta A Creative Component submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Computer Engineering Program of Study Committee: Mai Zheng, Major Professor The student author, whose presentation of the scholarship herein was approved by the program of study committee, is solely responsible for the content of this creative component. The Graduate College will ensure this creative component is globally accessible and will not permit alterations after a degree is conferred. Iowa State University Ames, Iowa 2020 Copyright c Chander Bhushan Gupta, 2020. All rights reserved. ii TABLE OF CONTENTS Page LIST OF TABLES . iv LIST OF FIGURES . .v ACKNOWLEDGMENTS . vii ABSTRACT . viii CHAPTER 1. INTRODUCTION . .1 1.1 Motivation . .3 1.2 Related Work . .5 1.3 Outline . .6 CHAPTER 2. REVIEW OF LITERATURE . .7 2.1 Why FEMU? . -
Linux Networking 101
The Gorilla ® Guide to… Linux Networking 101 Inside this Guide: • Discover how Linux continues its march toward world domination • Learn basic Linux administration tips • See how easy it can be to build your entire network on a Linux foundation • Find out how Cumulus Linux is your ticket to networking freedom David M. Davis ActualTech Media Helping You Navigate The Technology Jungle! In Partnership With www.actualtechmedia.com The Gorilla Guide To… Linux Networking 101 Author David M. Davis, ActualTech Media Editors Hilary Kirchner, Dream Write Creative, LLC Christina Guthrie, Guthrie Writing & Editorial, LLC Madison Emery, Cumulus Networks Layout and Design Scott D. Lowe, ActualTech Media Copyright © 2017 by ActualTech Media. All rights reserved. No portion of this book may be reproduced or used in any manner without the express written permission of the publisher except for the use of brief quotations. The information provided within this eBook is for general informational purposes only. While we try to keep the information up- to-date and correct, there are no representations or warranties, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to the information, products, services, or related graphics contained in this book for any purpose. Any use of this information is at your own risk. ActualTech Media Okatie Village Ste 103-157 Bluffton, SC 29909 www.actualtechmedia.com Entering the Jungle Introduction: Six Reasons You Need to Learn Linux ....................................................... 7 1. Linux is the future ........................................................................ 9 2. Linux is on everything .................................................................. 9 3. Linux is adaptable ....................................................................... 10 4. Linux has a strong community and ecosystem ........................... 10 5. -
Practical Practical
PRACTICAL PRACTICAL GPLCOMPLIANCE GPLCOMPLIANCE A GUIDE FOR STARTUPS, SMALL ABUSINESSES GUIDE FOR STARTUPS, AND ENGINEERS SMALL BUSINESSES AND ENGINEERS ARMIJN HEMEL, MSC AND SHANE COUGHLAN ARMIJN HEMEL, MSC AND SHANE COUGHLAN Copyright © 2017 Linux Foundation All rights reserved. This book or any portion thereof may not be reproduced or used in any manner whatsoever without the express written permission of the publisher except for the use of brief quotations in a book review and certain other noncommercial uses permitted by copyright law. Printed in the United States of America First Edition, 2017 ISBN: 978-0-9989078-0-2 1 Letterman Drive Building D Suite D4700 San Francisco CA 94129 Phone/Fax: +1 415 723 9709 https://linuxfoundation.org About the Authors Shane Coughlan Shane Coughlan is an expert in communi- cation, security, and business development. His professional accomplishments include spearheading the licensing team that elevated Open Invention Network into the largest patent non-aggression community in history, establishing the leading professional network of open source legal experts, and aligning stakeholders to launch both the first law journal and the first law book dedicated to open source. He currently leads the OpenChain community as Program Manager. Shane has extensive knowledge of open source governance, internal process development, supply chain management, and community building. His experience includes engagement with the enterprise, embedded, mobile, and automotive industries. Armijn Hemel Armijn Hemel is the owner of Tjaldur Software Governance Solutions. He is an active re- searcher of and internationally recognized expert in open source license compliance and supply chain management. He studied computer science at Utrecht University in The Netherlands, where he pioneered reproducible builds with NixOS. -
Open Source Used in CVR100W 1.0.1.1X
Open Source Used In CVR100W 1.0.1.1x Cisco Systems, Inc. www.cisco.com Cisco has more than 200 offices worldwide. Addresses, phone numbers, and fax numbers are listed on the Cisco website at www.cisco.com/go/offices. Text Part Number: 78EE117C99-35996155 78-21097-01 Open Source Used In CVR100W 1.0.1.1x 1 This document contains the licenses and notices for open source software used in this product. With respect to the free/open source software listed in this document, if you have any questions or wish to receive a copy of the source code to which you are entitled under the applicable free/open source license(s) (such as the GNU Lesser/General Public License), please contact us at [email protected]. In your requests please include the following reference number 78EE117C99-35996155 En ce qui a trait au logiciel gratuit ou à exploitation libre figurant dans ce document, si vous avez des questions ou souhaitez recevoir une copie du code source, auquel vous avez droit en vertu des licences gratuites ou d'exploitation libre applicables (telles que licences GNU Lesser/General Public), veuillez communiquer avec nous à l'adresse external- [email protected]. Dans vos demandes, veuillez inclure le numéro de référence 78EE117C99-35996155 Contents 1.1 binutils 2.17 1.1.1 Available under license 1.2 brcm_rstp 0.21 1.2.1 Available under license 1.3 bridge-utils 1.0.6 1.3.1 Available under license 1.4 BusyBox 1.7.2 1.4.1 Available under license 1.5 config 1.0 1.5.1 Available under license 1.6 conntrack-tools 1.0.0 1.6.1 -
User Space TCP - Getting LKL Ready for the Prime Time
User Space TCP - Getting LKL Ready for the Prime Time H.K. Jerry Chu, Yuan Liu Google Inc. 1600 Amphitheatre Pkwy, Mountain View, CA 94043, USA [email protected], [email protected] Abstract ets destined for Google services may be initiated from a for- eign stack installed by a cloud customer running directly in- Running the networking stack in the user space is not new. The side Google’s data center. If these “guest” packets created by conventional wisdom is that the network stack must bypass the untrusted stacks are allowed into our internal networks un- kernel in order to meet the performance requirements of a class of applications that demand super-low latency. changed, and terminated directly by the Linux kernel TCP stack running on our internal servers, it poses a very high se- This paper describes an experiment we’ve undertaken to pro- vide a production- strength user space TCP stack for a different curity risk. On the other hand, forcing all the guest packets use case inside Googles internal production network. to route through GFEs in order to subject them to the rigor- We choose a Linux based open source project called Linux ous checks and filtering is undesirable, both from the cost and Kernel Library (LKL) as a base for our effort, and have made performance stand points. significant contribution to it since late last year, improving both Running a TCP stack in the user space to terminate guest its quality and performance. During the time, we discovered a connections provides a solution that much reduces our expo- number of architectural constraints inherited in the LKL’s cur- sure to the security risk, from the whole OS kernel down to rent design and implementation, and gained valuable insights a single user process. -
BERKELEY PACKET FILTER: Theory, Practice and Perspectives
Alma Mater Studiorum · Universita` di Bologna SCUOLA DI SCIENZE Corso di Laurea in Informatica BERKELEY PACKET FILTER: theory, practice and perspectives Relatore: Presentata da: Chiar.mo Prof. MICHELE DI STEFANO RENZO DAVOLI Sessione II Anno Accademico 2019/2020 All operating systems sucks, but Linux just sucks less. Linus Torvalds Introduction Initially packet filtering mechanism in many Unix versions was imple- mented in the userspace, meaning that each packet was copied from the kernel-space to the user-space before being filtered. This approach resulted to be inefficient compared with the performance shown by the introduction of the BSD classic Berkeley Packet Filter (cBPF). cBPF consists of an as- sembly language for a virtual machine which resides inside the kernel. The assembly language can be used to write filters that are loaded in to the ker- nel from the user-space allowing the filtering to happen in the kernel-space without copying each packet as before. cBPF use is not limited to just the networking domain but it is also applied as a mechanism to filter system calls through seccomp mode. Seccomp allows the programmer to arbitrary select which system calls to permit, representing an useful mechanism to implement sandboxing. In order to increase the number of use cases and to update the architecture accordingly to new advancements in modern processors, the virtual machine has been rewritten and new features have been added. The result is extended Berkeley Packet Filter (eBPF) which consists of a richer assembly, more pro- gram types, maps to store key/value pairs and more components. Currently eBPF (or just BPF) is under continuous development and its capacities are evolving, although the main uses are networking and tracing. -
Block Devices and Volume Management in Linux
Block devices and volume management in Linux Krzysztof Lichota [email protected] L i n u x b l o c k d e v i c e s l a y e r ● Linux block devices layer is pretty flexible and allows for some interesting features: – Pluggable I/O schedulers – I/O prioritizing (needs support from I/O scheduler) – Remapping of disk requests (Device Mapper) – RAID – Various tricks (multipath, fault injection) – I/O tracing (blktrace) s t r u c t b i o ● Basic block of I/O submission and completion ● Can represent large contiguous memory regions for I/O but also scattered regions ● Scattered regions can be passed directly to disks capable of scatter/gather ● bios can be split, merged with other requests by various levels of block layer (e.g. split by RAID, merged in disk driver with other disk requests) s t r u c t b i o f i e l d s ● bi_sector – start sector of I/O ● bi_size – size of I/O ● bi_bdev – device to which I/O is sent ● bi_flags – I/O flags ● bi_rw – read/write flags and priority ● bi_io_vec – memory scatter/gather vector ● bi_end_io - function called when I/O is completed ● bi_destructor – function called when bio is to be destroyed s t r u c t b i o u s a g e ● Allocate bio using bio_alloc() or similar function ● Fill in necessary fields (start, device, ...) ● Initialize bio vector ● Fill in end I/O function to be notified when bio completes ● Call submit_bio()/generic_make_request() ● Example: process_read() in dm-crypt O t h e r I / O s u b m i s s i o n f u n c t i o n s ● Older interfaces for submitting I/O are supported (but deprecated),