session 200 - core os networking

8/3/2019 Session 200 - Core OS Networking

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Overview

Brett R. Halle

Senior Director, CoreOS

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You are here

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One year, one month, 28 days left

New support, stack synchronized with Snow Leopard

Automatically obtains IPv6 prefix/address via router advertisement

DHCPv6 (stateless) for DNS server addresses, search domains, etc.

Most apps IPv6 ready to go!

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Stack, socket interface, CFNetwork IPv6 ready

If youre using CFNetwork, you may be done!Test your app with v6

If youre not using CFNetwork, be aware!

Check your older source code

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Write code for address independence Be aware of displaying/storing IP addresses, may be 128bits now

Use address independent hostname lookups (getaddrinfo)Expect multiple addresses (some IPv4, some IPv6)

Use sockaddrs NOT in_addr/in6_addr

Reorder socket / gethostbyname / connectto getaddrinfo / socket / connect

If your app listens for connections, listen for IPv6 only

Avoid using functions/structures that are IPv4 specific

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What is a captive network?

OS detects and rememberscaptive networks

Wi-Fi interface is unavailablewhile captive

New support for Hotspotmanagement apps

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Cisco and Juniper clients

OS Level plumbing

Vendor specific feature sets

Available via the App Store

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Networking behavior for background apps

When suspended: Networking sockets will persist for an arbitrary time

System may reclaim resources associated with socket

Be sure to respond to going to background notification

Respond to networking errors Read the documentation for various use-cases (e.g., VoIP)

See sessions: Adopting Multitasking on iPhone OS, Part 1

Adopting Multitasking on iPhone OS, Part 2

Simplifying Networking Using Bonjour

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225,000+ apps

Significant percentage arenetwork enabled

Mobility isnt the exception,its the norm

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System administrators configured

everythingTotal control of your local networkingenvironment

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Network configuration is

completely dynamic andcan be assumed to change

At any time and for virtuallyany reason

Signal strength Cell availability

Wi-Fi availability

Public and privateWi-Fi environments

VPN connectivity

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Things to remember while writing the next great app

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Usage may be charged

by time or amount 3G and/or Wi-Fi may be fee-based

3G may be roaming

Transmit only what you need to

Cache intelligently

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Connections will go downbe prepared

Packets will get dropped

Timeouts will occur

Respond to backgrounding intelligently

Close things down that you can

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Do NOT put synchronous

calls on main thread Your app will get shot!

Event-driven APIs give abetter experience

(e.g., Bonjour, FoundationAPIs using RunLoop eventsources, etc.)

UI should reflect this reality

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Wi-Fi

3G

Layered networks (Wi-Fi on cellular or worse)

Expect changes in

Speed Latency

Packet loss

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Network wont always be available

Might go away at any time Your app should behave intelligentlygracefully

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May be using public Wi-Fi, Hotspots, etc. Might even be using spoofed network

Do not transmit user information inthe clear

Use end-to-end security, TransportLevel Security (TLS), whenever possible

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Use CFNetwork and higher,

when possible Dont assume address typesor sizes

Be prepared for multiple DNS

address resolution responses Check open source and oldercode for v6 compatibility

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Its a dynamic world; nobody remembers

IP addresses Can you remember your IPv6 address?(2001:0200:0000:8002:0203:47ff:fea5:3085)

Bonjour provides service advertisement,

browsing, and resolving APIs Peer-to-peer

On desktop OS, Bonjour also providessleep proxy support

See session: Simplifying Networking Using Bonjour

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Portability means batteries

Dont power up the radio(s) more thanyou need to

Use push notifications

Sleep proxy support helps on Snow Leopard

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Anything can and WILL change Available interfaces Signal strength and quality

Dont leave connections openlonger than necessary

Use Reachability APIs NOT a preflight check

Change notifications

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Network Apps for iPhone OS, Part 1 Pacific HeightsWednesday 2:00PM

Network Apps for iPhone OS, Part 2 MarinaWednesday 3:15PM

Simplifying Networking Using Bonjour Nob HillWednesday 10:15AM

Adopting Multitasking on iPhone OS, Part 1Presidio

Tuesday 11:30AM

Adopting Multitasking on iPhone OS, Part 2 MissionTuesday 3:15PM

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Networking Lab Core OS Lab ATuesday 4:30PM

Networking Lab Core OS Lab BWednesday 9:00AM

Networking Lab Core OS Lab BThursday 9:00AM

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Networked apps add value for your customers

They expect a connected experience Be prepared for the challenges of the mobile world

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Paul DanboldEvangelist

[email protected]

DocumentationNetworkinghttp://developer.apple.com/networking/

Apple Developer Forumshttp://devforums.apple.com

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Network Apps for iPhone OS, Part 1 Pacific HeightsWednesday 2:00PM

Network Apps for iPhone OS, Part 2 MarinaWednesday 3:15PM

Simplifying Networking Using Bonjour Nob HillWednesday 10:15AM

Adopting Multitasking on iPhone OS, Part 1

Presidio

Tuesday 11:30AM

Adopting Multitasking on iPhone OS, Part 2 MissionTuesday 3:15PM

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Networking Lab Core OS Lab ATuesday 4:30PM

Networking Lab Core OS Lab BThursday 9:00AM

Networking Lab Core OS Lab BFriday 9:00AM

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session 200 - core os networking

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