passt: New design and implementation with native Layer 4 sockets
This is a reimplementation, partially building on the earlier draft,
that uses L4 sockets (SOCK_DGRAM, SOCK_STREAM) instead of SOCK_RAW,
providing L4-L2 translation functionality without requiring any
security capability.
Conceptually, this follows the design presented at:
https://gitlab.com/abologna/kubevirt-and-kvm/-/blob/master/Networking.md
The most significant novelty here comes from TCP and UDP translation
layers. In particular, the TCP state and translation logic follows
the intent of being minimalistic, without reimplementing a full TCP
stack in either direction, and synchronising as much as possible the
TCP dynamic and flows between guest and host kernel.
Another important introduction concerns addressing, port translation
and forwarding. The Layer 4 implementations now attempt to bind on
all unbound ports, in order to forward connections in a transparent
way.
While at it:
- the qemu 'tap' back-end can't be used as-is by qrap anymore,
because of explicit checks now introduced in qemu to ensure that
the corresponding file descriptor is actually a tap device. For
this reason, qrap now operates on a 'socket' back-end type,
accounting for and building the additional header reporting
frame length
- provide a demo script that sets up namespaces, addresses and
routes, and starts the daemon. A virtual machine started in the
network namespace, wrapped by qrap, will now directly interface
with passt and communicate using Layer 4 sockets provided by the
host kernel.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2021-02-16 06:25:09 +00:00
|
|
|
// SPDX-License-Identifier: AGPL-3.0-or-later
|
|
|
|
|
|
2020-07-20 14:41:49 +00:00
|
|
|
/* PASST - Plug A Simple Socket Transport
|
passt: Add PASTA mode, major rework
PASTA (Pack A Subtle Tap Abstraction) provides quasi-native host
connectivity to an otherwise disconnected, unprivileged network
and user namespace, similarly to slirp4netns. Given that the
implementation is largely overlapping with PASST, no separate binary
is built: 'pasta' (and 'passt4netns' for clarity) both link to
'passt', and the mode of operation is selected depending on how the
binary is invoked. Usage example:
$ unshare -rUn
# echo $$
1871759
$ ./pasta 1871759 # From another terminal
# udhcpc -i pasta0 2>/dev/null
# ping -c1 pasta.pizza
PING pasta.pizza (64.190.62.111) 56(84) bytes of data.
64 bytes from 64.190.62.111 (64.190.62.111): icmp_seq=1 ttl=255 time=34.6 ms
--- pasta.pizza ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 34.575/34.575/34.575/0.000 ms
# ping -c1 spaghetti.pizza
PING spaghetti.pizza(2606:4700:3034::6815:147a (2606:4700:3034::6815:147a)) 56 data bytes
64 bytes from 2606:4700:3034::6815:147a (2606:4700:3034::6815:147a): icmp_seq=1 ttl=255 time=29.0 ms
--- spaghetti.pizza ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 28.967/28.967/28.967/0.000 ms
This entails a major rework, especially with regard to the storage of
tracked connections and to the semantics of epoll(7) references.
Indexing TCP and UDP bindings merely by socket proved to be
inflexible and unsuitable to handle different connection flows: pasta
also provides Layer-2 to Layer-2 socket mapping between init and a
separate namespace for local connections, using a pair of splice()
system calls for TCP, and a recvmmsg()/sendmmsg() pair for UDP local
bindings. For instance, building on the previous example:
# ip link set dev lo up
# iperf3 -s
$ iperf3 -c ::1 -Z -w 32M -l 1024k -P2 | tail -n4
[SUM] 0.00-10.00 sec 52.3 GBytes 44.9 Gbits/sec 283 sender
[SUM] 0.00-10.43 sec 52.3 GBytes 43.1 Gbits/sec receiver
iperf Done.
epoll(7) references now include a generic part in order to
demultiplex data to the relevant protocol handler, using 24
bits for the socket number, and an opaque portion reserved for
usage by the single protocol handlers, in order to track sockets
back to corresponding connections and bindings.
A number of fixes pertaining to TCP state machine and congestion
window handling are also included here.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2021-07-17 06:34:53 +00:00
|
|
|
* for qemu/UNIX domain socket mode
|
|
|
|
|
*
|
|
|
|
|
* PASTA - Pack A Subtle Tap Abstraction
|
|
|
|
|
* for network namespace/tap device mode
|
2020-07-20 14:27:43 +00:00
|
|
|
*
|
|
|
|
|
* arp.c - ARP implementation
|
|
|
|
|
*
|
passt: New design and implementation with native Layer 4 sockets
This is a reimplementation, partially building on the earlier draft,
that uses L4 sockets (SOCK_DGRAM, SOCK_STREAM) instead of SOCK_RAW,
providing L4-L2 translation functionality without requiring any
security capability.
Conceptually, this follows the design presented at:
https://gitlab.com/abologna/kubevirt-and-kvm/-/blob/master/Networking.md
The most significant novelty here comes from TCP and UDP translation
layers. In particular, the TCP state and translation logic follows
the intent of being minimalistic, without reimplementing a full TCP
stack in either direction, and synchronising as much as possible the
TCP dynamic and flows between guest and host kernel.
Another important introduction concerns addressing, port translation
and forwarding. The Layer 4 implementations now attempt to bind on
all unbound ports, in order to forward connections in a transparent
way.
While at it:
- the qemu 'tap' back-end can't be used as-is by qrap anymore,
because of explicit checks now introduced in qemu to ensure that
the corresponding file descriptor is actually a tap device. For
this reason, qrap now operates on a 'socket' back-end type,
accounting for and building the additional header reporting
frame length
- provide a demo script that sets up namespaces, addresses and
routes, and starts the daemon. A virtual machine started in the
network namespace, wrapped by qrap, will now directly interface
with passt and communicate using Layer 4 sockets provided by the
host kernel.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2021-02-16 06:25:09 +00:00
|
|
|
* Copyright (c) 2020-2021 Red Hat GmbH
|
2020-07-20 14:27:43 +00:00
|
|
|
* Author: Stefano Brivio <sbrivio@redhat.com>
|
|
|
|
|
*/
|
|
|
|
|
|
2021-10-21 02:26:08 +00:00
|
|
|
#include <arpa/inet.h>
|
|
|
|
|
#include <limits.h>
|
|
|
|
|
#include <net/if.h>
|
|
|
|
|
#include <net/if_arp.h>
|
|
|
|
|
#include <netinet/if_ether.h>
|
2020-07-20 14:27:43 +00:00
|
|
|
#include <stddef.h>
|
|
|
|
|
#include <stdint.h>
|
2021-10-21 02:26:08 +00:00
|
|
|
#include <stdio.h>
|
2020-07-20 14:27:43 +00:00
|
|
|
#include <unistd.h>
|
|
|
|
|
#include <string.h>
|
2021-10-21 02:26:08 +00:00
|
|
|
|
passt: Add PASTA mode, major rework
PASTA (Pack A Subtle Tap Abstraction) provides quasi-native host
connectivity to an otherwise disconnected, unprivileged network
and user namespace, similarly to slirp4netns. Given that the
implementation is largely overlapping with PASST, no separate binary
is built: 'pasta' (and 'passt4netns' for clarity) both link to
'passt', and the mode of operation is selected depending on how the
binary is invoked. Usage example:
$ unshare -rUn
# echo $$
1871759
$ ./pasta 1871759 # From another terminal
# udhcpc -i pasta0 2>/dev/null
# ping -c1 pasta.pizza
PING pasta.pizza (64.190.62.111) 56(84) bytes of data.
64 bytes from 64.190.62.111 (64.190.62.111): icmp_seq=1 ttl=255 time=34.6 ms
--- pasta.pizza ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 34.575/34.575/34.575/0.000 ms
# ping -c1 spaghetti.pizza
PING spaghetti.pizza(2606:4700:3034::6815:147a (2606:4700:3034::6815:147a)) 56 data bytes
64 bytes from 2606:4700:3034::6815:147a (2606:4700:3034::6815:147a): icmp_seq=1 ttl=255 time=29.0 ms
--- spaghetti.pizza ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 28.967/28.967/28.967/0.000 ms
This entails a major rework, especially with regard to the storage of
tracked connections and to the semantics of epoll(7) references.
Indexing TCP and UDP bindings merely by socket proved to be
inflexible and unsuitable to handle different connection flows: pasta
also provides Layer-2 to Layer-2 socket mapping between init and a
separate namespace for local connections, using a pair of splice()
system calls for TCP, and a recvmmsg()/sendmmsg() pair for UDP local
bindings. For instance, building on the previous example:
# ip link set dev lo up
# iperf3 -s
$ iperf3 -c ::1 -Z -w 32M -l 1024k -P2 | tail -n4
[SUM] 0.00-10.00 sec 52.3 GBytes 44.9 Gbits/sec 283 sender
[SUM] 0.00-10.43 sec 52.3 GBytes 43.1 Gbits/sec receiver
iperf Done.
epoll(7) references now include a generic part in order to
demultiplex data to the relevant protocol handler, using 24
bits for the socket number, and an opaque portion reserved for
usage by the single protocol handlers, in order to track sockets
back to corresponding connections and bindings.
A number of fixes pertaining to TCP state machine and congestion
window handling are also included here.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2021-07-17 06:34:53 +00:00
|
|
|
#include "util.h"
|
2021-10-21 02:26:08 +00:00
|
|
|
#include "arp.h"
|
2020-07-20 14:27:43 +00:00
|
|
|
#include "dhcp.h"
|
2021-10-21 02:26:08 +00:00
|
|
|
#include "passt.h"
|
passt: New design and implementation with native Layer 4 sockets
This is a reimplementation, partially building on the earlier draft,
that uses L4 sockets (SOCK_DGRAM, SOCK_STREAM) instead of SOCK_RAW,
providing L4-L2 translation functionality without requiring any
security capability.
Conceptually, this follows the design presented at:
https://gitlab.com/abologna/kubevirt-and-kvm/-/blob/master/Networking.md
The most significant novelty here comes from TCP and UDP translation
layers. In particular, the TCP state and translation logic follows
the intent of being minimalistic, without reimplementing a full TCP
stack in either direction, and synchronising as much as possible the
TCP dynamic and flows between guest and host kernel.
Another important introduction concerns addressing, port translation
and forwarding. The Layer 4 implementations now attempt to bind on
all unbound ports, in order to forward connections in a transparent
way.
While at it:
- the qemu 'tap' back-end can't be used as-is by qrap anymore,
because of explicit checks now introduced in qemu to ensure that
the corresponding file descriptor is actually a tap device. For
this reason, qrap now operates on a 'socket' back-end type,
accounting for and building the additional header reporting
frame length
- provide a demo script that sets up namespaces, addresses and
routes, and starts the daemon. A virtual machine started in the
network namespace, wrapped by qrap, will now directly interface
with passt and communicate using Layer 4 sockets provided by the
host kernel.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2021-02-16 06:25:09 +00:00
|
|
|
#include "tap.h"
|
2020-07-20 14:27:43 +00:00
|
|
|
|
|
|
|
|
/**
|
treewide: Packet abstraction with mandatory boundary checks
Implement a packet abstraction providing boundary and size checks
based on packet descriptors: packets stored in a buffer can be queued
into a pool (without storage of its own), and data can be retrieved
referring to an index in the pool, specifying offset and length.
Checks ensure data is not read outside the boundaries of buffer and
descriptors, and that packets added to a pool are within the buffer
range with valid offset and indices.
This implies a wider rework: usage of the "queueing" part of the
abstraction mostly affects tap_handler_{passt,pasta}() functions and
their callees, while the "fetching" part affects all the guest or tap
facing implementations: TCP, UDP, ICMP, ARP, NDP, DHCP and DHCPv6
handlers.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-03-25 12:02:47 +00:00
|
|
|
* arp() - Check if this is a supported ARP message, reply as needed
|
2020-07-20 14:27:43 +00:00
|
|
|
* @c: Execution context
|
treewide: Packet abstraction with mandatory boundary checks
Implement a packet abstraction providing boundary and size checks
based on packet descriptors: packets stored in a buffer can be queued
into a pool (without storage of its own), and data can be retrieved
referring to an index in the pool, specifying offset and length.
Checks ensure data is not read outside the boundaries of buffer and
descriptors, and that packets added to a pool are within the buffer
range with valid offset and indices.
This implies a wider rework: usage of the "queueing" part of the
abstraction mostly affects tap_handler_{passt,pasta}() functions and
their callees, while the "fetching" part affects all the guest or tap
facing implementations: TCP, UDP, ICMP, ARP, NDP, DHCP and DHCPv6
handlers.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-03-25 12:02:47 +00:00
|
|
|
* @p: Packet pool, single packet with Ethernet buffer
|
2020-07-20 14:27:43 +00:00
|
|
|
*
|
treewide: Packet abstraction with mandatory boundary checks
Implement a packet abstraction providing boundary and size checks
based on packet descriptors: packets stored in a buffer can be queued
into a pool (without storage of its own), and data can be retrieved
referring to an index in the pool, specifying offset and length.
Checks ensure data is not read outside the boundaries of buffer and
descriptors, and that packets added to a pool are within the buffer
range with valid offset and indices.
This implies a wider rework: usage of the "queueing" part of the
abstraction mostly affects tap_handler_{passt,pasta}() functions and
their callees, while the "fetching" part affects all the guest or tap
facing implementations: TCP, UDP, ICMP, ARP, NDP, DHCP and DHCPv6
handlers.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-03-25 12:02:47 +00:00
|
|
|
* Return: 1 if handled, -1 on failure
|
2020-07-20 14:27:43 +00:00
|
|
|
*/
|
2022-03-26 06:23:21 +00:00
|
|
|
int arp(const struct ctx *c, const struct pool *p)
|
2020-07-20 14:27:43 +00:00
|
|
|
{
|
|
|
|
|
unsigned char swap[4];
|
treewide: Packet abstraction with mandatory boundary checks
Implement a packet abstraction providing boundary and size checks
based on packet descriptors: packets stored in a buffer can be queued
into a pool (without storage of its own), and data can be retrieved
referring to an index in the pool, specifying offset and length.
Checks ensure data is not read outside the boundaries of buffer and
descriptors, and that packets added to a pool are within the buffer
range with valid offset and indices.
This implies a wider rework: usage of the "queueing" part of the
abstraction mostly affects tap_handler_{passt,pasta}() functions and
their callees, while the "fetching" part affects all the guest or tap
facing implementations: TCP, UDP, ICMP, ARP, NDP, DHCP and DHCPv6
handlers.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-03-25 12:02:47 +00:00
|
|
|
struct ethhdr *eh;
|
|
|
|
|
struct arphdr *ah;
|
|
|
|
|
struct arpmsg *am;
|
|
|
|
|
size_t len;
|
2020-07-20 14:27:43 +00:00
|
|
|
|
treewide: Packet abstraction with mandatory boundary checks
Implement a packet abstraction providing boundary and size checks
based on packet descriptors: packets stored in a buffer can be queued
into a pool (without storage of its own), and data can be retrieved
referring to an index in the pool, specifying offset and length.
Checks ensure data is not read outside the boundaries of buffer and
descriptors, and that packets added to a pool are within the buffer
range with valid offset and indices.
This implies a wider rework: usage of the "queueing" part of the
abstraction mostly affects tap_handler_{passt,pasta}() functions and
their callees, while the "fetching" part affects all the guest or tap
facing implementations: TCP, UDP, ICMP, ARP, NDP, DHCP and DHCPv6
handlers.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-03-25 12:02:47 +00:00
|
|
|
eh = packet_get(p, 0, 0, sizeof(*eh), NULL);
|
|
|
|
|
ah = packet_get(p, 0, sizeof(*eh), sizeof(*ah), NULL);
|
|
|
|
|
am = packet_get(p, 0, sizeof(*eh) + sizeof(*ah), sizeof(*am), NULL);
|
2020-07-20 14:27:43 +00:00
|
|
|
|
treewide: Packet abstraction with mandatory boundary checks
Implement a packet abstraction providing boundary and size checks
based on packet descriptors: packets stored in a buffer can be queued
into a pool (without storage of its own), and data can be retrieved
referring to an index in the pool, specifying offset and length.
Checks ensure data is not read outside the boundaries of buffer and
descriptors, and that packets added to a pool are within the buffer
range with valid offset and indices.
This implies a wider rework: usage of the "queueing" part of the
abstraction mostly affects tap_handler_{passt,pasta}() functions and
their callees, while the "fetching" part affects all the guest or tap
facing implementations: TCP, UDP, ICMP, ARP, NDP, DHCP and DHCPv6
handlers.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-03-25 12:02:47 +00:00
|
|
|
if (!eh || !ah || !am)
|
2020-07-20 14:27:43 +00:00
|
|
|
return -1;
|
|
|
|
|
|
treewide: Packet abstraction with mandatory boundary checks
Implement a packet abstraction providing boundary and size checks
based on packet descriptors: packets stored in a buffer can be queued
into a pool (without storage of its own), and data can be retrieved
referring to an index in the pool, specifying offset and length.
Checks ensure data is not read outside the boundaries of buffer and
descriptors, and that packets added to a pool are within the buffer
range with valid offset and indices.
This implies a wider rework: usage of the "queueing" part of the
abstraction mostly affects tap_handler_{passt,pasta}() functions and
their callees, while the "fetching" part affects all the guest or tap
facing implementations: TCP, UDP, ICMP, ARP, NDP, DHCP and DHCPv6
handlers.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-03-25 12:02:47 +00:00
|
|
|
if (ah->ar_hrd != htons(ARPHRD_ETHER) ||
|
|
|
|
|
ah->ar_pro != htons(ETH_P_IP) ||
|
|
|
|
|
ah->ar_hln != ETH_ALEN ||
|
|
|
|
|
ah->ar_pln != 4 ||
|
|
|
|
|
ah->ar_op != htons(ARPOP_REQUEST))
|
2020-07-20 14:27:43 +00:00
|
|
|
return 1;
|
|
|
|
|
|
2021-08-19 17:44:31 +00:00
|
|
|
/* Discard announcements (but not 0.0.0.0 "probes"): we might have the
|
|
|
|
|
* same IP address, hide that.
|
|
|
|
|
*/
|
treewide: Packet abstraction with mandatory boundary checks
Implement a packet abstraction providing boundary and size checks
based on packet descriptors: packets stored in a buffer can be queued
into a pool (without storage of its own), and data can be retrieved
referring to an index in the pool, specifying offset and length.
Checks ensure data is not read outside the boundaries of buffer and
descriptors, and that packets added to a pool are within the buffer
range with valid offset and indices.
This implies a wider rework: usage of the "queueing" part of the
abstraction mostly affects tap_handler_{passt,pasta}() functions and
their callees, while the "fetching" part affects all the guest or tap
facing implementations: TCP, UDP, ICMP, ARP, NDP, DHCP and DHCPv6
handlers.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-03-25 12:02:47 +00:00
|
|
|
if (memcmp(am->sip, (unsigned char[4]){ 0 }, sizeof(am->tip)) &&
|
|
|
|
|
!memcmp(am->sip, am->tip, sizeof(am->sip)))
|
2021-08-19 17:44:31 +00:00
|
|
|
return 1;
|
|
|
|
|
|
2021-08-19 23:13:02 +00:00
|
|
|
/* Don't resolve our own address, either. */
|
treewide: Packet abstraction with mandatory boundary checks
Implement a packet abstraction providing boundary and size checks
based on packet descriptors: packets stored in a buffer can be queued
into a pool (without storage of its own), and data can be retrieved
referring to an index in the pool, specifying offset and length.
Checks ensure data is not read outside the boundaries of buffer and
descriptors, and that packets added to a pool are within the buffer
range with valid offset and indices.
This implies a wider rework: usage of the "queueing" part of the
abstraction mostly affects tap_handler_{passt,pasta}() functions and
their callees, while the "fetching" part affects all the guest or tap
facing implementations: TCP, UDP, ICMP, ARP, NDP, DHCP and DHCPv6
handlers.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-03-25 12:02:47 +00:00
|
|
|
if (!memcmp(am->tip, &c->addr4, sizeof(am->tip)))
|
2021-08-19 23:13:02 +00:00
|
|
|
return 1;
|
|
|
|
|
|
2020-07-20 14:27:43 +00:00
|
|
|
ah->ar_op = htons(ARPOP_REPLY);
|
treewide: Packet abstraction with mandatory boundary checks
Implement a packet abstraction providing boundary and size checks
based on packet descriptors: packets stored in a buffer can be queued
into a pool (without storage of its own), and data can be retrieved
referring to an index in the pool, specifying offset and length.
Checks ensure data is not read outside the boundaries of buffer and
descriptors, and that packets added to a pool are within the buffer
range with valid offset and indices.
This implies a wider rework: usage of the "queueing" part of the
abstraction mostly affects tap_handler_{passt,pasta}() functions and
their callees, while the "fetching" part affects all the guest or tap
facing implementations: TCP, UDP, ICMP, ARP, NDP, DHCP and DHCPv6
handlers.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-03-25 12:02:47 +00:00
|
|
|
memcpy(am->tha, am->sha, sizeof(am->tha));
|
|
|
|
|
memcpy(am->sha, c->mac, sizeof(am->sha));
|
2020-07-20 14:27:43 +00:00
|
|
|
|
treewide: Packet abstraction with mandatory boundary checks
Implement a packet abstraction providing boundary and size checks
based on packet descriptors: packets stored in a buffer can be queued
into a pool (without storage of its own), and data can be retrieved
referring to an index in the pool, specifying offset and length.
Checks ensure data is not read outside the boundaries of buffer and
descriptors, and that packets added to a pool are within the buffer
range with valid offset and indices.
This implies a wider rework: usage of the "queueing" part of the
abstraction mostly affects tap_handler_{passt,pasta}() functions and
their callees, while the "fetching" part affects all the guest or tap
facing implementations: TCP, UDP, ICMP, ARP, NDP, DHCP and DHCPv6
handlers.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-03-25 12:02:47 +00:00
|
|
|
memcpy(swap, am->tip, sizeof(am->tip));
|
|
|
|
|
memcpy(am->tip, am->sip, sizeof(am->tip));
|
|
|
|
|
memcpy(am->sip, swap, sizeof(am->sip));
|
2020-07-20 14:27:43 +00:00
|
|
|
|
|
|
|
|
len = sizeof(*eh) + sizeof(*ah) + sizeof(*am);
|
treewide: Packet abstraction with mandatory boundary checks
Implement a packet abstraction providing boundary and size checks
based on packet descriptors: packets stored in a buffer can be queued
into a pool (without storage of its own), and data can be retrieved
referring to an index in the pool, specifying offset and length.
Checks ensure data is not read outside the boundaries of buffer and
descriptors, and that packets added to a pool are within the buffer
range with valid offset and indices.
This implies a wider rework: usage of the "queueing" part of the
abstraction mostly affects tap_handler_{passt,pasta}() functions and
their callees, while the "fetching" part affects all the guest or tap
facing implementations: TCP, UDP, ICMP, ARP, NDP, DHCP and DHCPv6
handlers.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-03-25 12:02:47 +00:00
|
|
|
memcpy(eh->h_dest, eh->h_source, sizeof(eh->h_dest));
|
|
|
|
|
memcpy(eh->h_source, c->mac, sizeof(eh->h_source));
|
2020-07-20 14:27:43 +00:00
|
|
|
|
passt: Add PASTA mode, major rework
PASTA (Pack A Subtle Tap Abstraction) provides quasi-native host
connectivity to an otherwise disconnected, unprivileged network
and user namespace, similarly to slirp4netns. Given that the
implementation is largely overlapping with PASST, no separate binary
is built: 'pasta' (and 'passt4netns' for clarity) both link to
'passt', and the mode of operation is selected depending on how the
binary is invoked. Usage example:
$ unshare -rUn
# echo $$
1871759
$ ./pasta 1871759 # From another terminal
# udhcpc -i pasta0 2>/dev/null
# ping -c1 pasta.pizza
PING pasta.pizza (64.190.62.111) 56(84) bytes of data.
64 bytes from 64.190.62.111 (64.190.62.111): icmp_seq=1 ttl=255 time=34.6 ms
--- pasta.pizza ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 34.575/34.575/34.575/0.000 ms
# ping -c1 spaghetti.pizza
PING spaghetti.pizza(2606:4700:3034::6815:147a (2606:4700:3034::6815:147a)) 56 data bytes
64 bytes from 2606:4700:3034::6815:147a (2606:4700:3034::6815:147a): icmp_seq=1 ttl=255 time=29.0 ms
--- spaghetti.pizza ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 28.967/28.967/28.967/0.000 ms
This entails a major rework, especially with regard to the storage of
tracked connections and to the semantics of epoll(7) references.
Indexing TCP and UDP bindings merely by socket proved to be
inflexible and unsuitable to handle different connection flows: pasta
also provides Layer-2 to Layer-2 socket mapping between init and a
separate namespace for local connections, using a pair of splice()
system calls for TCP, and a recvmmsg()/sendmmsg() pair for UDP local
bindings. For instance, building on the previous example:
# ip link set dev lo up
# iperf3 -s
$ iperf3 -c ::1 -Z -w 32M -l 1024k -P2 | tail -n4
[SUM] 0.00-10.00 sec 52.3 GBytes 44.9 Gbits/sec 283 sender
[SUM] 0.00-10.43 sec 52.3 GBytes 43.1 Gbits/sec receiver
iperf Done.
epoll(7) references now include a generic part in order to
demultiplex data to the relevant protocol handler, using 24
bits for the socket number, and an opaque portion reserved for
usage by the single protocol handlers, in order to track sockets
back to corresponding connections and bindings.
A number of fixes pertaining to TCP state machine and congestion
window handling are also included here.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2021-07-17 06:34:53 +00:00
|
|
|
if (tap_send(c, eh, len, 0) < 0)
|
2020-07-20 14:27:43 +00:00
|
|
|
perror("ARP: send");
|
|
|
|
|
|
|
|
|
|
return 1;
|
|
|
|
|
}
|