3eb26fecf5
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
663 lines
29 KiB
Markdown
663 lines
29 KiB
Markdown
<!---
|
|
SPDX-License-Identifier: AGPL-3.0-or-later
|
|
Copyright (c) 2021-2022 Red Hat GmbH
|
|
Author: Stefano Brivio <sbrivio@redhat.com>
|
|
-->
|
|
|
|
<style scoped>
|
|
.mobile_hide {
|
|
visibility: hidden;
|
|
display: none;
|
|
}
|
|
img {
|
|
visibility: hidden;
|
|
display: none;
|
|
}
|
|
li {
|
|
margin: 10px;
|
|
}
|
|
|
|
@media only screen and (min-width: 768px) {
|
|
.mobile_hide {
|
|
visibility: visible;
|
|
display: inherit;
|
|
}
|
|
img {
|
|
visibility: visible;
|
|
display: inherit;
|
|
}
|
|
li {
|
|
margin: 0px;
|
|
}
|
|
}
|
|
|
|
.mobile_show {
|
|
visibility: visible;
|
|
display: inherit;
|
|
}
|
|
@media only screen and (min-width: 768px) {
|
|
.mobile_show {
|
|
visibility: hidden;
|
|
display: none;
|
|
}
|
|
}
|
|
</style>
|
|
|
|
# passt: Plug A Simple Socket Transport
|
|
|
|
_passt_ implements a translation layer between a Layer-2 network interface and
|
|
native Layer-4 sockets (TCP, UDP, ICMP/ICMPv6 echo) on a host. It doesn't
|
|
require any capabilities or privileges, and it can be used as a simple
|
|
replacement for Slirp.
|
|
|
|
<div class="mobile_hide">
|
|
<picture>
|
|
<source type="image/webp" srcset="/builds/latest/web/passt_overview.webp">
|
|
<source type="image/png" srcset="/builds/latest/web/passt_overview.png">
|
|
<img src="/builds/latest/web/passt_overview.png" usemap="#image-map" class="bright" style="z-index: 20; position: relative;" alt="Overview diagram of passt">
|
|
</picture>
|
|
<map name="image-map" id="map_overview" class="mobile_hide">
|
|
<area class="map_area" target="_blank" href="https://man7.org/linux/man-pages/man7/tcp.7.html" coords="229,275,246,320,306,294,287,249" shape="poly">
|
|
<area class="map_area" target="_blank" href="https://lwn.net/Articles/420799/" coords="230,201,243,246,297,232,289,186" shape="poly">
|
|
<area class="map_area" target="_blank" href="https://man7.org/linux/man-pages/man7/udp.7.html" coords="234,129,236,175,297,169,293,126" shape="poly">
|
|
<area class="map_area" target="_blank" href="https://en.wiktionary.org/wiki/passen#German" coords="387,516,841,440,847,476,393,553" shape="poly">
|
|
<area class="map_area" target="_blank" href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv4/udp.c" coords="398,123,520,157" shape="rect">
|
|
<area class="map_area" target="_blank" href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv4/ping.c" coords="397,164,517,197" shape="rect">
|
|
<area class="map_area" target="_blank" href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv4/tcp.c" coords="398,203,516,237" shape="rect">
|
|
<area class="map_area" target="_blank" href="https://man7.org/linux/man-pages/man7/unix.7.html" coords="569,306,674,359" shape="rect">
|
|
<area class="map_area" target="_blank" href="/passt/tree/udp.c" coords="719,152,740,176,792,134,768,108" shape="poly">
|
|
<area class="map_area" target="_blank" href="/passt/tree/icmp.c" coords="727,206,827,120,854,150,754,238" shape="poly">
|
|
<area class="map_area" target="_blank" href="/passt/tree/tcp.c" coords="730,273,774,326,947,176,902,119" shape="poly">
|
|
<area class="map_area" target="_blank" href="/passt/tree/igmp.c" coords="865,273,912,295" shape="rect">
|
|
<area class="map_area" target="_blank" href="/passt/tree/arp.c" coords="854,300,897,320" shape="rect">
|
|
<area class="map_area" target="_blank" href="/passt/tree/ndp.c" coords="869,325,909,344" shape="rect">
|
|
<area class="map_area" target="_blank" href="/passt/tree/mld.c" coords="924,267,964,289" shape="rect">
|
|
<area class="map_area" target="_blank" href="/passt/tree/dhcpv6.c" coords="918,297,986,317" shape="rect">
|
|
<area class="map_area" target="_blank" href="/passt/tree/dhcp.c" coords="931,328,981,352" shape="rect">
|
|
<area class="map_area" target="_blank" href="https://man7.org/linux/man-pages/man7/udp.7.html" coords="1073,115,1059,154,1120,176,1133,137" shape="poly">
|
|
<area class="map_area" target="_blank" href="https://lwn.net/Articles/420799/" coords="966,113,942,152,1000,175,1017,136" shape="poly">
|
|
<area class="map_area" target="_blank" href="https://man7.org/linux/man-pages/man7/tcp.7.html" coords="1059,175,1039,213,1098,237,1116,197" shape="poly">
|
|
<area class="map_area" target="_blank" href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv4/udp.c" coords="1203,154,1326,189" shape="rect">
|
|
<area class="map_area" target="_blank" href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv4/ping.c" coords="1202,195,1327,228" shape="rect">
|
|
<area class="map_area" target="_blank" href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv4/tcp.c" coords="1204,236,1327,269" shape="rect">
|
|
<area class="map_area" target="_blank" href="https://en.wikipedia.org/wiki/OSI_model#Layer_architecture" coords="1159,52,1325,147" shape="rect">
|
|
<area class="map_area" target="_blank" href="https://man7.org/linux/man-pages/man4/veth.4.html" coords="1119,351,1157,339,1198,340,1236,345,1258,359,1229,377,1176,377,1139,375,1114,365" shape="poly">
|
|
<area class="map_area" target="_blank" href="https://man7.org/linux/man-pages/man4/veth.4.html" coords="1044,471,1090,461,1126,462,1150,464,1176,479,1160,491,1121,500,1081,501,1044,491,1037,483" shape="poly">
|
|
<area class="map_area" target="_blank" href="https://man7.org/linux/man-pages/man7/network_namespaces.7.html" coords="240,379,524,452" shape="rect">
|
|
<area class="map_area" target="_blank" href="https://man7.org/linux/man-pages/man7/netlink.7.html" coords="1119,278,1117,293,1165,304,1169,288" shape="poly">
|
|
<area class="map_area" target="_blank" href="/passt/tree/conf.c" coords="989,294,1040,264,1089,280,986,344" shape="poly">
|
|
</map>
|
|
<canvas id="map_highlight" style="border: 0px; z-index: 10; position: fixed; pointer-events: none"></canvas>
|
|
</div>
|
|
<script>
|
|
function canvas_position(el) {
|
|
var rect = el.getBoundingClientRect();
|
|
var canvas = document.getElementById('map_highlight');
|
|
|
|
canvas.width = rect.right - rect.left;
|
|
canvas.height = rect.bottom - rect.top;
|
|
canvas.style.left = rect.left + 'px';
|
|
canvas.style.top = rect.top + 'px';
|
|
}
|
|
|
|
function map_hover() {
|
|
var coords = this.coords.split(',');
|
|
var canvas = document.getElementById('map_highlight');
|
|
var ctx = canvas.getContext('2d');
|
|
|
|
canvas_position(this);
|
|
|
|
ctx.fillStyle = 'rgba(255, 255, 255, .3)';
|
|
ctx.lineWidth = 1.5;
|
|
ctx.strokeStyle = 'rgba(255, 255, 100, 1)';
|
|
|
|
ctx.beginPath();
|
|
ctx.setLineDash([15, 15]);
|
|
if (this.shape == "poly") {
|
|
ctx.moveTo(coords[0], coords[1]);
|
|
for (item = 2; item < coords.length - 1; item += 2) {
|
|
ctx.lineTo(coords[item], coords[item + 1])
|
|
}
|
|
} else if (this.shape == "rect") {
|
|
ctx.rect(coords[0], coords[1],
|
|
coords[2] - coords[0], coords[3] - coords[1]);
|
|
}
|
|
|
|
ctx.closePath();
|
|
ctx.stroke();
|
|
ctx.fill();
|
|
}
|
|
|
|
function map_out() {
|
|
var canvas = document.getElementById('map_highlight');
|
|
var ctx = canvas.getContext('2d');
|
|
|
|
ctx.clearRect(0, 0, canvas.width, canvas.height);
|
|
}
|
|
|
|
var map_areas = document.getElementsByClassName("map_area");
|
|
|
|
for (var i = 0; i < map_areas.length; i++) {
|
|
map_areas[i].onmouseover = map_hover;
|
|
map_areas[i].onmouseout = map_out;
|
|
}
|
|
</script>
|
|
|
|
# pasta: Pack A Subtle Tap Abstraction
|
|
|
|
_pasta_ (same binary as _passt_, different command) offers equivalent
|
|
functionality, for network namespaces: traffic is forwarded using a tap
|
|
interface inside the namespace, without the need to create further interfaces on
|
|
the host, hence not requiring any capabilities or privileges.
|
|
|
|
It also implements a tap bypass path for local connections: packets with a local
|
|
destination address are moved directly between Layer-4 sockets, avoiding Layer-2
|
|
translations, using the _splice_(2) and _recvmmsg_(2)/_sendmmsg_(2) system calls
|
|
for TCP and UDP, respectively.
|
|
|
|
<div class="mobile_hide">
|
|
<picture>
|
|
<source type="image/webp" srcset="/builds/latest/web/pasta_overview.webp">
|
|
<source type="image/png" srcset="/builds/latest/web/pasta_overview.png">
|
|
<img src="/builds/latest/web/passt_overview.png" class="bright" style="z-index: 20; position: relative;" alt="Overview diagram of pasta">
|
|
</picture>
|
|
</div>
|
|
|
|
- [Motivation](#motivation)
|
|
- [Features](#features)
|
|
- [Interfaces and Environment](#interfaces-and-environment)
|
|
- [Services](#services)
|
|
- [Addresses](#addresses)
|
|
- [Protocols](#protocols)
|
|
- [Ports](#ports)
|
|
- [Demo](#demo)
|
|
- [Continuous Integration](#continuous-integration)
|
|
- [Performance](#performance_1)
|
|
- [Try it](#try-it)
|
|
- [Contribute](#contribute)
|
|
- [Security and Vulnerability Reports](#security-and-vulnerability-reports)
|
|
|
|
See also the [man page](/builds/latest/web/passt.1.html).
|
|
|
|
## Motivation
|
|
|
|
### passt
|
|
|
|
When container workloads are moved to virtual machines, the network traffic is
|
|
typically forwarded by interfaces operating at data link level. Some components
|
|
in the containers ecosystem (such as _service meshes_), however, expect
|
|
applications to run locally, with visible sockets and processes, for the
|
|
purposes of socket redirection, monitoring, port mapping.
|
|
|
|
To solve this issue, user mode networking, as provided e.g. by _libslirp_,
|
|
can be used. Existing solutions implement a full TCP/IP stack, replaying traffic
|
|
on sockets that are local to the pod of the service mesh. This creates the
|
|
illusion of application processes running on the same host, eventually separated
|
|
by user namespaces.
|
|
|
|
While being almost transparent to the service mesh infrastructure, that kind of
|
|
solution comes with a number of downsides:
|
|
|
|
* three different TCP/IP stacks (guest, adaptation and host) need to be
|
|
traversed for every service request
|
|
* addressing needs to be coordinated to create the pretense of consistent
|
|
addresses and routes between guest and host environments. This typically needs
|
|
a NAT with masquerading, or some form of packet bridging
|
|
* the traffic seen by the service mesh and observable externally is a distant
|
|
replica of the packets forwarded to and from the guest environment:
|
|
* TCP congestion windows and network buffering mechanisms in general operate
|
|
differently from what would be naturally expected by the application
|
|
* protocols carrying addressing information might pose additional challenges,
|
|
as the applications don't see the same set of addresses and routes as they
|
|
would if deployed with regular containers
|
|
|
|
_passt_ implements a thinner layer between guest and host, that only implements
|
|
what's strictly needed to pretend processes are running locally. The TCP
|
|
adaptation doesn't keep per-connection packet buffers, and reflects observed
|
|
sending windows and acknowledgements between the two sides. This TCP adaptation
|
|
is needed as _passt_ runs without the `CAP_NET_RAW` capability: it can't create
|
|
raw IP sockets on the pod, and therefore needs to map packets at Layer-2 to
|
|
Layer-4 sockets offered by the host kernel.
|
|
|
|
See also a
|
|
[detailed illustration](https://gitlab.com/abologna/kubevirt-and-kvm/-/blob/master/Networking.md)
|
|
of the problem and what lead to this approach.
|
|
|
|
### pasta
|
|
|
|
On Linux, regular users can create network namespaces and run application
|
|
services inside them. However, connecting namespaces to other namespaces and to
|
|
external hosts requires the creation of network interfaces, such as `veth`
|
|
pairs, which needs in turn elevated privileges or the `CAP_NET_ADMIN`
|
|
capability. _pasta_, similarly to _slirp4netns_, solves this problem by creating
|
|
a tap interface available to processes in the namespace, and mapping network
|
|
traffic outside the namespace using native Layer-4 sockets.
|
|
|
|
Existing approaches typically implement a full, generic TCP/IP stack for this
|
|
translation between data and transport layers, without the possibility of
|
|
speeding up local connections, and usually requiring NAT. _pasta_:
|
|
|
|
* avoids the need for a generic, full-fledged TCP/IP stack by coordinating TCP
|
|
connection dynamics between sender and receiver
|
|
* offers a fast bypass path for local connections: if a process connects to
|
|
another process on the same host across namespaces, data is directly forwarded
|
|
using pairs of Layer-4 sockets
|
|
* with default options, maps routing and addressing information to the
|
|
namespace, avoiding any need for NAT
|
|
|
|
## Features
|
|
|
|
✅: done/supported, ❌: out of scope, 🛠: in progress/being considered
|
|
⌚: nice-to-have, eventually
|
|
|
|
### Protocols
|
|
* ✅ IPv4
|
|
* ✅ all features, except for
|
|
* ❌ fragmentation
|
|
* ✅ IPv6
|
|
* ✅ all features, except for
|
|
* ❌ fragmentation
|
|
* ❌ jumbograms
|
|
* ✅ [TCP](/passt/tree/tcp.c)
|
|
* ✅ Window Scaling (RFC 7323)
|
|
* ✅ Defenses against Sequence Number Attacks (RFC 6528)
|
|
* ⌚ [Protection Against Wrapped Sequences](https://bugs.passt.top/show_bug.cgi?id=1) (PAWS, RFC 7323)
|
|
* ⌚ [Timestamps](https://bugs.passt.top/show_bug.cgi?id=1) (RFC 7323)
|
|
* ❌ Selective Acknowledgment (RFC 2018)
|
|
* ✅ [UDP](/passt/tree/udp.c)
|
|
* ✅ ICMP/ICMPv6 Echo
|
|
* ⌚ [IGMP/MLD](https://bugs.passt.top/show_bug.cgi?id=2) proxy
|
|
* ⌚ [SCTP](https://bugs.passt.top/show_bug.cgi?id=3)
|
|
|
|
### Portability
|
|
* Linux
|
|
* ✅ starting from 4.18 kernel version
|
|
* ✅ starting from 3.13 kernel version
|
|
* ✅ run-time selection of AVX2 build
|
|
* ⌚ [_musl_](https://bugs.passt.top/show_bug.cgi?id=4) and
|
|
[_uClibc-ng_](https://bugs.passt.top/show_bug.cgi?id=5)
|
|
* ⌚ [FreeBSD](https://bugs.passt.top/show_bug.cgi?id=6),
|
|
[Darwin](https://bugs.passt.top/show_bug.cgi?id=6)
|
|
* ⌚ [NetBSD](https://bugs.passt.top/show_bug.cgi?id=7),
|
|
[OpenBSD](https://bugs.passt.top/show_bug.cgi?id=7)
|
|
* ⌚ [Win2k](https://bugs.passt.top/show_bug.cgi?id=8)
|
|
|
|
### Security
|
|
* ✅ no dynamic memory allocation (`sbrk`(2), `brk`(2), `mmap`(2) [blocked via
|
|
`seccomp`](/passt/tree/seccomp.sh))
|
|
* ✅ root operation not allowed outside user namespaces
|
|
* ✅ all capabilities dropped, other than `CAP_NET_BIND_SERVICE` (if granted)
|
|
* ✅ with default options, user, mount, IPC, UTS, PID namespaces are detached
|
|
* ✅ no external dependencies (other than a standard C library)
|
|
* ✅ restrictive seccomp profiles (30 syscalls allowed for _passt_, 41 for
|
|
_pasta_ on x86_64)
|
|
* ✅ examples of [AppArmor](/passt/tree/contrib/apparmor) and
|
|
[SELinux](/passt/tree/contrib/selinux) profiles available
|
|
* ✅ static checkers in continuous integration (clang-tidy, cppcheck)
|
|
* ✅️ clearly defined boundary-checked packet abstraction
|
|
* 🛠️ ~5 000 LoC target
|
|
* ⌚ [fuzzing](https://bugs.passt.top/show_bug.cgi?id=9), _packetdrill_ tests
|
|
* ⌚ stricter [synflood protection](https://bugs.passt.top/show_bug.cgi?id=10)
|
|
* 💡 [add](https://lists.passt.top/) [your](https://bugs.passt.top/)
|
|
[ideas](https://chat.passt.top)
|
|
|
|
### Configurability
|
|
* ✅ all addresses, ports, port ranges
|
|
* ✅ optional NAT, not required
|
|
* ✅ all protocols
|
|
* ✅ _pasta_: auto-detection of bound ports
|
|
* 🛠 run-time configuration of port ranges without autodetection
|
|
* 🛠 configuration of port ranges for autodetection
|
|
* 💡 [add](https://lists.passt.top/) [your](https://bugs.passt.top/)
|
|
[ideas](https://chat.passt.top)
|
|
|
|
### Performance
|
|
* ✅ maximum two (cache hot) copies on every data path
|
|
* ✅ _pasta_: zero-copy for local connections by design (no configuration
|
|
needed)
|
|
* ✅ generalised coalescing and batching on every path for every supported
|
|
protocol
|
|
* ✅ 4 to 50 times IPv4 TCP throughput of existing, conceptually similar
|
|
solutions depending on MTU (UDP and IPv6 hard to compare)
|
|
* 🛠 [_vhost-user_ support](https://bugs.passt.top/show_bug.cgi?id=25) for
|
|
maximum one copy on every data path and lower request-response latency
|
|
* ⌚ [multithreading](https://bugs.passt.top/show_bug.cgi?id=13)
|
|
* ⌚ [raw IP socket support](https://bugs.passt.top/show_bug.cgi?id=14) if
|
|
`CAP_NET_RAW` is granted
|
|
* ⌚ eBPF support (might not improve performance over vhost-user)
|
|
|
|
### Interfaces
|
|
* ✅ qemu, libvirt support with [`qrap` wrapper](/passt/tree/qrap.c)
|
|
* ✅ out-of-tree patches for [qemu](/passt/tree/contrib/qemu) and
|
|
[libvirt](/passt/tree/contrib/libvirt) available
|
|
* ✅ Podman [integration](https://github.com/containers/podman/pull/16141)
|
|
* ✅ bug-to-bug compatible
|
|
[_slirp4netns_ replacement](/passt/tree/slirp4netns.sh)
|
|
* ✅ out-of-tree patch for
|
|
[Kata Containers](/passt/tree/contrib/kata-containers) available
|
|
* 🛠 native [qemu](https://bugs.passt.top/show_bug.cgi?id=11),
|
|
[libvirt](https://bugs.passt.top/show_bug.cgi?id=12) support
|
|
* ⌚ drop-in replacement for VPNKit (rootless Docker)
|
|
|
|
### Availability
|
|
* ✅ official [packages](https://tracker.debian.org/pkg/passt) for Debian
|
|
* ✅ official [packages](https://src.fedoraproject.org/rpms/passt) for Fedora
|
|
* ✅ unofficial
|
|
[packages](https://copr.fedorainfracloud.org/coprs/sbrivio/passt/) for CentOS
|
|
Stream, EPEL, Mageia
|
|
* ✅ unofficial [packages](https://passt.top/builds/latest/x86_64/) from x86_64
|
|
static builds for other RPM-based distributions
|
|
* ✅ unofficial [packages](https://passt.top/builds/latest/x86_64/) from x86_64
|
|
static builds for Debian-based distributions
|
|
* ✅ testing on non-x86_64 architectures (aarch64, armv7l, i386, ppc64, ppc64le,
|
|
s390x)
|
|
* 🛠 official
|
|
[openSUSE packages](https://build.opensuse.org/package/show/home:dfaggioli:devel/passt)
|
|
* ⌚ official packages for Arch Linux
|
|
|
|
### Services
|
|
* ✅ built-in [ARP proxy](/passt/tree/arp.c)
|
|
* ✅ minimalistic [DHCP server](/passt/tree/dhcp.c)
|
|
* ✅ minimalistic [NDP proxy](/passt/tree/ndp.c) with router advertisements and
|
|
SLAAC support
|
|
* ✅ minimalistic [DHCPv6 server](/passt/tree/dhcpv6.c)
|
|
* ⌚ fine-grained configurability of DHCP, NDP, DHCPv6 options
|
|
|
|
## Interfaces and Environment
|
|
|
|
_passt_ exchanges packets with _qemu_ via UNIX domain socket, using the `socket`
|
|
back-end in qemu. This is supported since qemu 7.2.
|
|
|
|
For older versions, the [qrap](/passt/tree/qrap.c) wrapper can be used to
|
|
connect to a UNIX domain socket and to start qemu, which can now use the file
|
|
descriptor that's already opened.
|
|
|
|
This approach, compared to using a _tap_ device, doesn't require any security
|
|
capabilities, as we don't need to create any interface.
|
|
|
|
_pasta_ runs out of the box with any recent (post-3.8) Linux kernel.
|
|
|
|
## Services
|
|
|
|
_passt_ and _pasta_ provide some minimalistic implementations of networking
|
|
services:
|
|
|
|
* [ARP proxy](/passt/tree/arp.c), that resolves the address of
|
|
the host (which is used as gateway) to the original MAC address of the host
|
|
* [DHCP server](/passt/tree/dhcp.c), a simple implementation
|
|
handing out one single IPv4 address to the guest or namespace, namely, the
|
|
same address as the first one configured for the upstream host interface, and
|
|
passing the nameservers configured on the host
|
|
* [NDP proxy](/passt/tree/ndp.c), which can also assign prefix
|
|
and nameserver using SLAAC
|
|
* [DHCPv6 server](/passt/tree/dhcpv6.c): a simple
|
|
implementation handing out one single IPv6 address to the guest or namespace,
|
|
namely, the the same address as the first one configured for the upstream host
|
|
interface, and passing the nameservers configured on the host
|
|
|
|
## Addresses
|
|
|
|
For IPv4, the guest or namespace is assigned, via DHCP, the same address as the
|
|
upstream interface of the host, and the same default gateway as the default
|
|
gateway of the host. Addresses are translated in case the guest is seen using a
|
|
different address from the assigned one.
|
|
|
|
For IPv6, the guest or namespace is assigned, via SLAAC, the same prefix as the
|
|
upstream interface of the host, the same default route as the default route of
|
|
the host, and, if a DHCPv6 client is running in the guest or namespace, also the
|
|
same address as the upstream address of the host. This means that, with a DHCPv6
|
|
client in the guest or namespace, addresses don't need to be translated. Should
|
|
the client use a different address, the destination address is translated for
|
|
packets going to the guest or to the namespace.
|
|
|
|
### Local connections with _passt_
|
|
|
|
For UDP and TCP, for both IPv4 and IPv6, packets from the host addressed to a
|
|
loopback address are forwarded to the guest with their source address changed to
|
|
the address of the gateway or first hop of the default route. This mapping is
|
|
reversed on the other way.
|
|
|
|
### Local connections with _pasta_
|
|
|
|
Packets addressed to a loopback address in either namespace are directly
|
|
forwarded to the corresponding (or configured) port in the other namespace.
|
|
Similarly as _passt_, packets from the non-init namespace addressed to the
|
|
default gateway, which are therefore sent via the tap device, will have their
|
|
destination address translated to the loopback address.
|
|
|
|
## Protocols
|
|
|
|
_passt_ and _pasta_ support TCP, UDP and ICMP/ICMPv6 echo (requests and
|
|
replies). More details about the TCP implementation are described in the
|
|
[theory of operation](/passt/tree/tcp.c), and similarly for
|
|
[UDP](/passt/tree/udp.c).
|
|
|
|
An IGMP/MLD proxy is currently work in progress.
|
|
|
|
## Ports
|
|
|
|
### passt
|
|
|
|
To avoid the need for explicit port mapping configuration, _passt_ can bind to
|
|
all unbound non-ephemeral (0-49152) TCP and UDP ports. Binding to low ports
|
|
(0-1023) will fail without additional capabilities, and ports already bound
|
|
(service proxies, etc.) will also not be used. Smaller subsets of ports, with
|
|
port translations, are also configurable.
|
|
|
|
UDP ephemeral ports are bound dynamically, as the guest uses them.
|
|
|
|
If all ports are forwarded, service proxies and other services running in the
|
|
container need to be started before _passt_ starts.
|
|
|
|
### pasta
|
|
|
|
With default options, _pasta_ scans for bound ports on init and non-init
|
|
namespaces, and automatically forwards them from the other side. Port forwarding
|
|
is fully configurable with command line options.
|
|
|
|
## Demo
|
|
|
|
### pasta
|
|
|
|
<link rel="stylesheet" type="text/css" href="/static/asciinema-player.css" />
|
|
<script src="/static/asciinema-player.min.js"></script>
|
|
|
|
<div class="mobile_hide" id="demo_pasta_div" style="display: grid; grid-template-columns: 1fr 1fr;">
|
|
<div id="demo_pasta" style="width: 99%;"></div>
|
|
<div id="demo_podman" style="width: 99%;"></div>
|
|
</div>
|
|
<script>
|
|
if (getComputedStyle(document.getElementById('demo_pasta_div'))['visibility'] == "visible") {
|
|
demo_pasta_player = AsciinemaPlayer.create('/builds/latest/web/demo_pasta.cast',
|
|
document.getElementById('demo_pasta'),
|
|
{ cols: 130, rows: 41,
|
|
preload: true, poster: 'npt:0:4'
|
|
});
|
|
|
|
demo_podman_player = AsciinemaPlayer.create('/builds/latest/web/demo_podman.cast',
|
|
document.getElementById('demo_podman'),
|
|
{ cols: 130, rows: 41,
|
|
preload: true, poster: 'npt:0:4'
|
|
});
|
|
}
|
|
</script>
|
|
<div class="mobile_show">
|
|
<p><a href="/builds/latest/web/demo_pasta.html">Overview of pasta functionality</a></p>
|
|
<p><a href="/builds/latest/web/demo_podman.html">Overview of Podman operation with pasta</a></p>
|
|
</div>
|
|
|
|
### passt
|
|
|
|
<div class="mobile_hide" id="demo_passt" style="width: 70%; height: auto; max-height: 90%"></div>
|
|
<script>
|
|
if (getComputedStyle(document.getElementById('demo_passt'))['visibility'] == "visible") {
|
|
demo_passt_player = AsciinemaPlayer.create('/builds/latest/web/demo_passt.cast',
|
|
document.getElementById('demo_passt'),
|
|
{ cols: 130, rows: 41,
|
|
preload: true, poster: 'npt:0:4'
|
|
});
|
|
}
|
|
</script>
|
|
<div class="mobile_show">
|
|
<p><a href="/builds/latest/web/demo_passt.html">Overview of passt functionality</a></p>
|
|
</div>
|
|
|
|
## Continuous Integration
|
|
|
|
<div class="mobile_hide" id="ci" style="width: 90%; height: auto; max-height: 90%"></div>
|
|
<script>
|
|
if (getComputedStyle(document.getElementById('ci'))['visibility'] == "visible") {
|
|
ci_player = AsciinemaPlayer.create('/builds/latest/web/ci.cast',
|
|
document.getElementById('ci'),
|
|
{ cols: 240, rows: 51, poster: 'npt:999:0' }
|
|
);
|
|
}
|
|
</script>
|
|
<div class="mobile_hide"><script src="/builds/latest/web/ci.js"></script></div>
|
|
<div class="mobile_show">
|
|
<p><a href="/builds/latest/web/ci.html">Continuous integration test run</a></p>
|
|
</div>
|
|
|
|
See also the [test logs](/builds/latest/test/).
|
|
|
|
## Performance
|
|
|
|
<script src="/builds/latest/web/perf.js"></script>
|
|
|
|
## Try it
|
|
|
|
### passt
|
|
|
|
* build from source:
|
|
|
|
git clone https://passt.top/passt
|
|
cd passt
|
|
make
|
|
|
|
* alternatively, install one of the available packages:
|
|
|
|
* [Debian](https://tracker.debian.org/pkg/passt) (official)
|
|
* [Fedora](https://src.fedoraproject.org/rpms/passt) (official)
|
|
* [CentOS Stream](https://copr.fedorainfracloud.org/coprs/sbrivio/passt/) (unofficial)
|
|
* [EPEL](https://copr.fedorainfracloud.org/coprs/sbrivio/passt/) (unofficial)
|
|
* [Mageia](https://copr.fedorainfracloud.org/coprs/sbrivio/passt/) (unofficial)
|
|
* [openSUSE](https://build.opensuse.org/package/show/home:dfaggioli:devel/passt) (unofficial)
|
|
* [Debian-based](/builds/latest/x86_64/) (unofficial, from static x86_64 builds)
|
|
* [Other RPM-based distributions](/builds/latest/x86_64/) (unofficial, from static x86_64 builds)
|
|
|
|
Static binaries and packages are simply built with:
|
|
|
|
make pkgs
|
|
|
|
* have a look at the _man_ page for synopsis and options:
|
|
|
|
man ./passt.1
|
|
|
|
* run the demo script, that detaches user and network namespaces, configures the
|
|
new network namespace using `pasta`, starts `passt` and, optionally, `qemu`:
|
|
|
|
doc/demo.sh
|
|
|
|
* alternatively, you can use libvirt, with
|
|
[this patch](/passt/tree/libvirt/0001-conf-Introduce-support-for-UNIX-domain-socket-as-qem.patch),
|
|
to start qemu (with [these patches](/passt/tree/contrib/qemu)), and this kind
|
|
of network interface configuration:
|
|
|
|
<interface type='client'>
|
|
<mac address='52:54:00:02:6b:60'/>
|
|
<source path='/tmp/passt.socket'/>
|
|
<model type='virtio'/>
|
|
<address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
|
|
</interface>
|
|
|
|
* and that's it, you should now have TCP connections, UDP, and ICMP/ICMPv6
|
|
echo working from/to the guest for IPv4 and IPv6
|
|
|
|
* to connect to a service on the VM, just connect to the same port directly
|
|
with the address of the current network namespace
|
|
|
|
### pasta
|
|
|
|
* build from source:
|
|
|
|
git clone https://passt.top/passt
|
|
cd passt
|
|
make
|
|
|
|
* alternatively, install one of the available packages:
|
|
|
|
* [Debian](https://tracker.debian.org/pkg/passt) (official)
|
|
* [Fedora](https://src.fedoraproject.org/rpms/passt) (official)
|
|
* [CentOS Stream](https://copr.fedorainfracloud.org/coprs/sbrivio/passt/) (unofficial)
|
|
* [EPEL](https://copr.fedorainfracloud.org/coprs/sbrivio/passt/) (unofficial)
|
|
* [Mageia](https://copr.fedorainfracloud.org/coprs/sbrivio/passt/) (unofficial)
|
|
* [openSUSE](https://build.opensuse.org/package/show/home:dfaggioli:devel/passt) (unofficial)
|
|
* [Debian-based](/builds/latest/x86_64/) (unofficial, from static x86_64 builds)
|
|
* [Other RPM-based distributions](/builds/latest/x86_64/) (unofficial, from static x86_64 builds)
|
|
|
|
Static binaries and packages are simply built with:
|
|
|
|
make pkgs
|
|
|
|
* have a look at the _man_ page for synopsis and options:
|
|
|
|
man ./pasta.1
|
|
|
|
* start pasta with:
|
|
|
|
./pasta
|
|
|
|
* alternatively, use it directly with Podman (since Podman 4.3.2, or with
|
|
commit [`aa47e05ae4a0`](https://github.com/containers/podman/commit/aa47e05ae4a0d14a338cbe106b7eb9cdf098a529)):
|
|
|
|
podman run --net=pasta ...
|
|
|
|
* you're now inside a new user and network namespace. For IPv6, SLAAC happens
|
|
right away as _pasta_ sets up the interface, but DHCPv6 support is available
|
|
as well. For IPv4, configure the interface with a DHCP client:
|
|
|
|
dhclient
|
|
|
|
and, optionally:
|
|
|
|
dhclient -6
|
|
|
|
* alternatively, start pasta as:
|
|
|
|
./pasta --config-net
|
|
|
|
to let pasta configure networking in the namespace by itself, using
|
|
`netlink`
|
|
|
|
* ...or run the demo script:
|
|
|
|
doc/demo.sh
|
|
|
|
* and that's it, you should now have TCP connections, UDP, and ICMP/ICMPv6
|
|
echo working from/to the namespace for IPv4 and IPv6
|
|
|
|
* to connect to a service inside the namespace, just connect to the same port
|
|
using the loopback address.
|
|
|
|
## Contribute
|
|
|
|
### [Mailing Lists](/passt/lists)
|
|
* Submit, review patches, and discuss development ideas on
|
|
[`passt-dev`](https://lists.passt.top/postorius/lists/passt-dev.passt.top/)
|
|
|
|
* Ask your questions and discuss usage needs on
|
|
[`passt-user`](https://lists.passt.top/postorius/lists/passt-user.passt.top/)
|
|
|
|
### [Bug Reports and Feature Requests](/passt/bugs)
|
|
* **Pick up an [open bug](https://bugs.passt.top/buglist.cgi?bug_severity=blocker&bug_severity=quite%20bad&bug_severity=normal&bug_severity=minor&columnlist=bug_status%2Ccomponent%2Cpriority%2Cbug_severity%2Cassigned_to%2Cshort_desc%2Cchangeddate&known_name=Open%20bugs%2C%20by%20priority&list_id=85&query_based_on=Open%20bugs%2C%20by%20priority&query_format=advanced&resolution=---)**
|
|
* **Implement a [feature request](https://bugs.passt.top/buglist.cgi?bug_severity=enhancement&bug_severity=feature&columnlist=bug_status%2Ccomponent%2Cpriority%2Cbug_severity%2Cassigned_to%2Cshort_desc%2Cchangeddate&known_name=Features%2C%20by%20priority&list_id=81&order=priority%2Cbug_status%2Cassigned_to%2Cbug_id&query_based_on=Features%2C%20by%20priority&query_format=advanced&resolution=---)**
|
|
* Browse all [open items](https://bugs.passt.top/buglist.cgi?columnlist=bug_status%2Ccomponent%2Cpriority%2Cbug_severity%2Cassigned_to%2Cshort_desc%2Cchangeddate&known_name=All%20items%2C%20by%20priority&list_id=83&query_based_on=All%20items%2C%20by%20priority&query_format=advanced&resolution=---)
|
|
* ...or [file a bug](https://bugs.passt.top/enter_bug.cgi)
|
|
|
|
### [Chat](/passt/chat)
|
|
* Somebody might be available on [IRC](https://irc.passt.top)
|
|
|
|
## Security and Vulnerability Reports
|
|
|
|
* Please send an email to [passt-sec](mailto:passt-sec@passt.top), private list,
|
|
no subscription required
|