desconstruindo a web
Post on 29-Jan-2018
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Desconstruindo a webWillian Molinari (a.k.a PotHix)
Aviso
Willian Molinaria.k.a PotHix
Plaev.github.io
Porque dessa talk?
https://www.youtube.com/watch?v=nG1oGfrDiUc
https://www.youtube.com/watch?v=nG1oGfrDiUc
Essa talk se baseia em
Internet
Internet
The dawn of the net
Internet
“O que significa PotHix”
“O que significa PotHix”
http://pothix.com
http://pothix.com
Tem HSTS?
Strict-Transport-Security
http://pothix.com
Tem cache?
Expires Cache-Control
http://pothix.com
Protocolo: http://Domínio: pothix.com
Path: /
Tem cache de DNS?
ChromeFaz cache de DNS
http://aosabook.org/en/posa/high-performance-networking-in-chrome.html
getaddrinfo()
sistema operacional
glibc -> /etc/hostsnss/nss_files/files-hosts.c
glibc -> getaddrinfo()sysdeps/posix/getaddrinfo.c
2321 getaddrinfo (const char *name, const char *service, 2322 const struct addrinfo *hints, struct addrinfo **pai) 2323 {
getaddrinfo()Tem nscd para cache de DNS?
Internet
- glibc
POSIX
Aplicação
Apresentação
Sessão
Transporte
Rede
Enlace
Físico
ModeloOSI
Aplicação
Apresentação
Sessão
Transporte
Rede
Enlace
Físico
ModeloOSI
SRLY?
Aplicação
Transporte
Rede
Enlace
Físico
Sessão
Apresentação
Aplicação
Transporte
Rede
Enlace
Físico
Aplicação
Transporte
Rede
Enlace
Físico
SOuser
TCP / UDP
DNSAplicação
Transporte
Rede
Enlace
Físico
IP
Ethernet / Wi-Fi
010101001011
DNS
TCP / UDP
Aplicação
Transporte
Rede
Enlace
Físico
IP
Ethernet / Wi-Fi
010101001011
código disponível em: chromium/src/net/dns
getaddrinfo()__socket() & __connect()
sysdeps/posix/getaddrinfo.c2515 fd = __socket (af, SOCK_DGRAM, IPPROTO_IP); [...]2526 [...] && __connect (fd, q->ai_addr, q->ai_addrlen) == 0
terminal
$ sudo strace -f -e bind,socket,fork,connect -p $(ps aux | grep chromium | grep -v nacl | awk '{ print $2}' | xargs echo | sed 's/ /,/g')[...][pid 8739] socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP) = 134[pid 8739] connect(134, {sa_family=AF_INET6, sin6_port=htons(53), inet_pton(AF_INET6, "2001:4860:4860::8888", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = -1 ENETUNREACH (Network is unreachable)[pid 9010] socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 134[pid 9010] connect(134, {sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("192.30.252.154")}, 16) = 0[pid 8739] socket(PF_INET, SOCK_STREAM, IPPROTO_TCP) = 134[pid 8739] connect(134, {sa_family=AF_INET, sin_port=htons(80), sin_addr=inet_addr("192.30.252.154")}, 16) = -1 EINPROGRESS (Operation now in progress)[...]
Syscalls in action! (*stripped)
terminal
$ sudo strace -f -e bind,socket,fork,connect -p $(ps aux | grep chromium | grep -v nacl | awk '{ print $2}' | xargs echo | sed 's/ /,/g')[...][pid 8739] socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP) = 134[pid 8739] connect(134, {sa_family=AF_INET6, sin6_port=htons(53), inet_pton(AF_INET6, "2001:4860:4860::8888", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = -1 ENETUNREACH (Network is unreachable)[pid 9010] socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 134[pid 9010] connect(134, {sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("192.30.252.154")}, 16) = 0[pid 8739] socket(PF_INET, SOCK_STREAM, IPPROTO_TCP) = 134[pid 8739] connect(134, {sa_family=AF_INET, sin_port=htons(80), sin_addr=inet_addr("192.30.252.154")}, 16) = -1 EINPROGRESS (Operation now in progress)[...]
Syscalls in action! (*stripped)
UDP para ipv6nope :(
UDPipv4
request
Happy eyebals (rfc6555): https://www.ietf.org/mail-archive/web/v6ops/current/msg22455.html
DNSAplicação
Transporte
Rede
Enlace
Físico
TCP / UDP
IP
Ethernet / Wi-Fi
010101001011
UDP/IPlinux/blob/master/net/ipv4/udp.c
UDP
Conteúdo
Endereço (IP)
?
DNSAplicação
Transporte
Rede
Enlace
Físico
TCP / UDP
IP
Ethernet / Wi-Fi
010101001011
DNSAplicação
Transporte
Rede
Enlace
Físico
TCP / UDP
IP
Mágica, bro!
A visual explanation of how dns lookups work
Via dnstracer: `dnstracer -s . -4 -o pothix.com`
A.ROOT-SERVERS.NET [.] (198.41.0.4)
a.gtld-servers.net [com] (192.5.6.30)
ns1.dreamhost.com [pothix.com] (66.33.206.206) Got authoritative answer
ns1.dreamhost.com (66.33.206.206) pothix.com -> 192.30.252.153ns1.dreamhost.com (66.33.206.206)pothix.com -> 192.30.252.154
Internet
glibcDNS
TCP/IP
UDP/IP
POSIX
Internet
glibcDNS
TCP/IP
UDP/IP
POSIX
HTTP
HTTP/HTTPS
TCP / UDP
IP
Ethernet / Wi-Fi
010101001011
Aplicação
Transporte
Rede
Enlace
Físico
HTTP/HTTPS
TCP / UDP
IP
Ethernet / Wi-Fi
010101001011
Aplicação
Transporte
Rede
Enlace
Físico
TCPlinux/blob/master/net/ipv4/tcp.c
https://en.wikipedia.org/wiki/Transmission_Control_Protocol
ACK
SYN + ACK
ACK
Three way handshake
LISTENINGSYN
LISTENSYNSENT
SYN+ACK
LISTENSYNRECEIVEDSYNSENT
SYNRECEIVEDSYNSENTESTABLISHED
ACK
ESTABLISHEDSYNSENTESTABLISHED
É NÓIS! É NÓIS!
HTTP/HTTPS
TCP / UDP
IP
Ethernet / Wi-Fi
010101001011
Aplicação
Transporte
Rede
Enlace
Físico
HTTPS
TLS = fork(SSLv3)SSLv3 is no longer supported in chrome
HTTP/HTTPS
TCP / UDP
IP
Ethernet / Wi-Fi
010101001011
Aplicação
Transporte
Rede
Enlace
Físico
TLS
TLS
conexão estabelecida
client hello (CIPHERS, URL)
Os primeiros milisegundos de uma conexão HTTPS
https://cc.dcsec.uni-hannover.de/
conexão estabelecida
Server hello(certificado, CIPHER)
TLS_RSA_WITH_RC4_128_MD5
publickey
crypt hash
conexão estabelecida
Data válida?CA confiável?
Assinatura válida?URL esperada?
conexão estabelecida
conexão estabelecida
Gerei uma parada aqui(pre_master secret)
!^*@#$&!@(#$&!@#)$^$^
TLS_RSA_WITH_RC4_128_MD5
conexão estabelecida
!!@U#$N!Y*@#$*
master secret
TLS_RSA_WITH_RC4_128_MD5
conexão estabelecida
É NÓIS!
TLS_RSA_WITH_RC4_128_MD5
criptografiados dados
verificação contra conteúdo “batizado”
É NÓIS!
TLSHTTP HTTP
Internet
headersurlcookies
headersurlcookies
HTTP/HTTP2chromium - net/http & net/spdy
Rafael RinaldiDissecando o protocolo HTTP/2
HTTP 1x via telnet
$ telnet pothix.com 80Trying 192.30.252.153...Connected to pothix.com.Escape character is '^]'.GET /index.html HTTP/1.1Host: pothix.com
HTTP/1.1 200 OKServer: GitHub.com...
terminal
HTTP/HTTPS
TCP / UDP
IP
Ethernet / Wi-Fi
010101001011
Aplicação
Transporte
Rede
Enlace
Físico
Aplicação
Transporte
Rede
Enlace
Físico
HTTP/HTTPS
TCP / UDP
IP
Ethernet / Wi-Fi
010101001011
Aplicação
Transporte
Rede
Enlace
Físico
papers/Vipin_Analysis_of_open_source_WLAN_driver_paper.pdf
➔ net/ipv4/tcp.c
➔ include/net/cfg80211.h➔ net/wireless/nl80211.c➔ include/net/mac80211.h
➔ drivers/net/wireless/iwlwifi/
InternetglibcDNS
TCP/IP
UDP/IP
HTTP
POSIX
Carrier
Sense
Multiple
Access
Collision
Avoidance
G
GB G
glibcDNS
TCP/IP
UDP/IP
HTTP
POSIX
Internet
# traceroute -T pothix.com
traceroute to pothix.com (192.30.252.153), 30 hops max, 60 byte packets
1 palantir (192.168.1.1) 8.718 ms 8.769 ms 8.868 ms
2 10.18.128.1 (10.18.128.1) 25.058 ms 25.673 ms 27.189 ms
3 c8bd5001.virtua.com.br (200.189.80.1) 29.071 ms 29.073 ms 29.068 ms
4 embratel-T0-7-2-0-tacc01.spoph.embratel.net.br (200.178.127.57) 32.917 ms
embratel-T0-4-1-0-uacc03.spomb.embratel.net.br (189.42.182.37) 31.734 ms
embratel-T0-1-0-2-uacc04.spoph.embratel.net.br (201.56.189.9) 36.481 ms
5 ebt-H0-1-0-0-tcore01.spolp.embratel.net.br (200.230.1.242) 37.800 ms
200.244.212.73 (200.244.212.73) 37.803 ms
200.244.212.81 (200.244.212.81) 41.446 ms
6 ebt-BP1082-intl02.nyk.embratel.net.br (200.230.220.30) 204.822 ms
ebt-B11121-intl02.nyk.embratel.net.br (200.230.251.254) 192.381 ms
ebt-BP11521-intl02.nyk.embratel.net.br (200.230.220.174) 189.936 ms
7 fa-0-0-0.r23.nycmny01.us.bb.gin.ntt.net (129.250.202.185) 192.297 ms 172.074 ms 172.013 ms
8 ae-9.r22.asbnva02.us.bb.gin.ntt.net (129.250.2.149) 171.973 ms 167.012 ms 166.951 ms
9 ae-44.r06.asbnva02.us.bb.gin.ntt.net (129.250.6.113) 166.888 ms 166.873 ms
ae-45.r05.asbnva02.us.bb.gin.ntt.net (129.250.5.137) 212.669 ms
10 xe-0-3-0-18.r05.asbnva02.us.ce.gin.ntt.net (129.250.197.70) 202.448 ms
xe-0-9-0-16.r06.asbnva02.us.ce.gin.ntt.net (129.250.197.74) 201.593 ms 202.489 ms
11 pages.github.com (192.30.252.153) 171.337 ms * *
TCP meu router
github pages USA backbone
backboneembratel
NET
Internet
Nginx conf fileupstream backend { server backend1.example.com weight=5; server backend2.example.com:8080; server unix:/tmp/backend3;
server backup1.example.com:8080 backup; server backup2.example.com:8080 backup;}
...
http://nginx.org/en/docs/http/ngx_http_upstream_module.html#server
TCP
Unix Socket
Internet
assets
TCP
http://12factor.net/port-binding
HTTP parsingragel vindo lá do velho mongrel*
*de acordo com o documento de design do unicorn
Internet
assets
TCP
Webserver -> Frameworkbaseado no PEP3333
Internet
assets
TCP
lib/rails/application.rbRack -> Rails
mais informações no post do timaro no omniref
É um Rack application ...
# Implements call according to the Rack API. It simply
# dispatches the request to the underlying middleware stack.
def call(env)
env["ORIGINAL_FULLPATH"] = build_original_fullpath(env)
env["ORIGINAL_SCRIPT_NAME"] = env["SCRIPT_NAME"]
super(env)
end
...
mais informações no post do timaro no omniref
Informações do Rack{"GATEWAY_INTERFACE"=>"CGI/1.1",
"PATH_INFO"=>"/favicon.ico",
"QUERY_STRING"=>"",
"REMOTE_ADDR"=>"127.0.0.1",
"REMOTE_HOST"=>"localhost.localdomain",
"REQUEST_METHOD"=>"GET",
"REQUEST_URI"=>"http://localhost:9292/favicon.ico",
"SCRIPT_NAME"=>"",
"SERVER_NAME"=>"localhost",
"SERVER_PORT"=>"9292",
"SERVER_PROTOCOL"=>"HTTP/1.1",
"SERVER_SOFTWARE"=>"WEBrick/1.3.1 (Ruby/2.2.3/2015-08-18)",
"HTTP_HOST"=>"localhost:9292",
"HTTP_CONNECTION"=>"keep-alive",
"HTTP_USER_AGENT"=>"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.71 Safari/537.36",
"HTTP_ACCEPT"=>"*/*",
"HTTP_REFERER"=>"http://localhost:9292/",
"HTTP_ACCEPT_ENCODING"=>"gzip, deflate, sdch",
"HTTP_ACCEPT_LANGUAGE"=>"en-US,en;q=0.8,pt-BR;q=0.6,pt;q=0.4,es;q=0.2,eo;q=0.2", "rack.version"=>[1, 2],
"rack.multithread"=>true, "rack.multiprocess"=>false, "rack.run_once"=>false, "rack.url_scheme"=>"http", "HTTP_VERSION"=>"HTTP/1.1", "REQUEST_PATH"=>"/favicon.ico"}
Rails::EngineTodas as apps são Engines
mais informações no post do timaro no omniref
mais informações no post do timaro no omniref
Rack middlewares[
Rack::Sendfile,
ActionDispatch::Static, Rack::Lock,
#<ActiveSupport::Cache::Strategy::LocalCache::Middleware:0x000000028fa168>,
Rack::Runtime, Rack::MethodOverride,
ActionDispatch::RequestId,
Rails::Rack::Logger,
ActionDispatch::ShowExceptions,
WebConsole::Middleware,
ActionDispatch::DebugExceptions,
ActionDispatch::RemoteIp,
ActionDispatch::Reloader,
ActionDispatch::Callbacks,
ActiveRecord::Migration::CheckPending,
ActiveRecord::ConnectionAdapters::ConnectionManagement,
ActiveRecord::QueryCache,
ActionDispatch::Cookies,
ActionDispatch::Session::CookieStore,
ActionDispatch::Flash,
ActionDispatch::ParamsParser,
Rack::Head,
Rack::ConditionalGet,
Rack::ETag
]
ActionDispatch::Journey::Router
a primeira parte do seu código a ser tocada
mais informações no post do timaro no omniref
req.path_parameters => {:controller=>"pages", :action=>"home"}
ActionDispatch::Routing::RouteSet::Dispatcher
achando o controller via rotas
mais informações no post do timaro no omniref
ActiveSupport::Dependencies.constantize("#{params[:controller].camelize}Controller") => PagesController
ActionController::Metalprepara o request e manda processar
mais informações no post do timaro no omniref
def dispatch(name, request) #:nodoc:
[...]
process(name)
AbstractController::Baseencaminha para o seu controller
mais informações no post do timaro no omniref
def process(action, *args)
[...]
process_action(action_name, *args) # que no fim é só um `send`
Internet
assets
TCP
MV
VM
C
Internet
assets
TCP
MV
VM
C
Internet
assets
TCP
MV
VM
C
pega aí Rack -> [status, header, body]
mais informações no post do timaro no omniref
ActionDispatch::Journey::Router
Internet
assets
TCP
MV
VM
C
Internet
assets
TCP
MV
VM
C
Internet
assets
TCP
MV
VM
C
Internet
assets
TCP
MV
VM
C
glibcDNS
TCP/IP
UDP/IP
HTTP
POSIX
Internet
glibcDNS
TCP/IP
UDP/IP
HTTP
POSIX
Internet
glibcDNS
TCP/IP
UDP/IP
HTTP
POSIX
Internet
glibcDNS
TCP/IP
UDP/IP
HTTP
POSIX
Internet
glibcDNS
TCP/IP
UDP/IP
HTTP
POSIX
Internet
c-c-c-combo breaker
HTML
exemplos retirados do post “How browsers work”
algoritmo de parsingimplementado no webkit do chrome
HEAD
exemplos retirados do post “How browsers work”
algoritmo de parsingimplementado no webkit do chrome
HTML syntax error
<img src=”http://pothix.com/avatar.gif”> thread
<img src=”http://pothix.com/esperanto.png”> thread
<img src=”http://pothix.com/fotodasferias.scr”> thread
<script src=”http://pothix.com/marotagem.js”> sincrono
<script src=”http://pothix.com/estiloso.css”> thread
<script src=”http://pothix.com/javaescrito.js”> sincrono
<img src=”http://pothix.com/fotodasferias.jpg”>
<img src=”http://pothix.com/avatar.gif”> thread
<img src=”http://pothix.com/esperanto.png”> thread
<img src=”http://pothix.com/fotodasferias.scr”> thread
<script src=”http://pothix.com/marotagem.js”> sincrono
<script src=”http://pothix.com/estiloso.css”> thread
<script src=”http://pothix.com/javaescrito.js”> sincrono
<img src=”http://pothix.com/fotodasferias.jpg”>
exemplos retirados do post “How browsers work”
exemplos retirados do post “How browsers work”
Diego Eis: DOM, CSSOM e RenderThree - Introdução ao Browser Render Path
Resumindoessa bagaça
glibc
MV
VM
C
Internet
Internet
Não acredite em mágicaentenda como funciona de verdade
ceeeeerto.
Seja curiosoconhecimento nunca é demais
Perguntas?
Willian Molinari
@PotHixpothix@pothix.com
Slides: https://goo.gl/cC36RM
SRLY?
The browser
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