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* passt: Align pkt_buf to PAGE_SIZE (start and size), try to fit in huge pagesStefano Brivio2021-09-271-0/+1
| | | | | | | | | If transparent huge pages are available, madvise() will do the trick. While at it, decrease EPOLL_EVENTS for the main loop from 10 to 8, for slightly better socket fairness. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt, pasta: Introduce command-line options and port re-mappingStefano Brivio2021-09-011-5/+9
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Introduce scatter-gather IO path from socket to tapStefano Brivio2021-07-261-0/+2
| | | | | | | | | | | | | | | | | ...similarly to what was done for UDP. Quick performance test with 32KiB buffers, host to VM: $ iperf3 -c 192.0.2.2 -N [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.00 sec 8.47 GBytes 7.27 Gbits/sec 0 sender [ 5] 0.00-10.00 sec 8.45 GBytes 7.26 Gbits/sec receiver $ iperf3 -c 2a01:598:88ba:a056:271f:473a:c0d9:abc1 [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.00 sec 8.43 GBytes 7.24 Gbits/sec 0 sender [ 5] 0.00-10.00 sec 8.41 GBytes 7.22 Gbits/sec receiver Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp, udp: Allow binding ports in init namespace to both tap and loopbackStefano Brivio2021-07-261-2/+8
| | | | | | | | Traffic with loopback source address will be forwarded to the direct loopback connection in the namespace, and the tap interface is used for the rest. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* checksum: Introduce AVX2 implementation, unify helpersStefano Brivio2021-07-261-4/+0
| | | | | | | | | | | | | | | | | | | Provide an AVX2-based function using compiler intrinsics for TCP/IP-style checksums. The load/unpack/add idea and implementation is largely based on code from BESS (the Berkeley Extensible Software Switch) licensed as 3-Clause BSD, with a number of modifications to further decrease pipeline stalls and to minimise cache pollution. This speeds up considerably data paths from sockets to tap interfaces, decreasing overhead for checksum computation, with 16-64KiB packet buffers, from approximately 11% to 7%. The rest is just syscalls at this point. While at it, provide convenience targets in the Makefile for avx2, avx2_debug, and debug targets -- these simply add target-specific CFLAGS to the build. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* udp: Introduce recvmmsg()/sendmmsg(), zero-copy path from socketStefano Brivio2021-07-211-0/+59
| | | | | | | | | | Packets are received directly onto pre-cooked, static buffers for IPv4 (with partial checksum pre-calculation) and IPv6 frames, with pre-filled Ethernet addresses and, partially, IP headers, and sent out from the same buffers with sendmmsg(), for both passt and pasta (non-local traffic only) modes. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Add PASTA mode, major reworkStefano Brivio2021-07-171-2/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* passt: Add support for multiple instances in different network namespacesStefano Brivio2021-05-211-0/+7
| | | | | | | | | | | | | ...sharing the same filesystem. Instead of a fixed path for the UNIX domain socket, passt now uses a path with a counter, probing for existing instances, and picking the first free one. The demo script is updated accordingly -- it can now be started several times to create multiple namespaces with an instance of passt each, with addressing reflecting separate subnets, and NDP proxying between them. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* dhcp, ndp, dhcpv6: Support for multiple DNS servers, search listStefano Brivio2021-05-211-1/+6
| | | | | | | | | | | Add support for a variable amount of DNS servers, including zero, from /etc/resolv.conf, in DHCP, NDP and DHCPv6 implementations. Introduce support for domain search list for DHCP (RFC 3397), NDP (RFC 8106), and DHCPv6 (RFC 3646), also sourced from /etc/resolv.conf. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* udp, passt: Introduce socket packet buffer, avoid getsockname() for UDPStefano Brivio2021-04-301-0/+1
| | | | | | | | | | This is in preparation for scatter-gather IO on the UDP receive path: save a getsockname() syscall by setting a flag if we get the numbering of all bound sockets in a strict sequence (expected, in practice) and repurpose the tap buffer to be also a socket receive buffer, passing it down to protocol handlers. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* udp: Connection tracking for ephemeral, local ports, and related fixesStefano Brivio2021-04-291-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As we support UDP forwarding for packets that are sent to local ports, we actually need some kind of connection tracking for UDP. While at it, this commit introduces a number of vaguely related fixes for issues observed while trying this out. In detail: - implement an explicit, albeit minimalistic, connection tracking for UDP, to allow usage of ephemeral ports by the guest and by the host at the same time, by binding them dynamically as needed, and to allow mapping address changes for packets with a loopback address as destination - set the guest MAC address whenever we receive a packet from tap instead of waiting for an ARP request, and set it to broadcast on start, otherwise DHCPv6 might not work if all DHCPv6 requests time out before the guest starts talking IPv4 - split context IPv6 address into address we assign, global or site address seen on tap, and link-local address seen on tap, and make sure we use the addresses we've seen as destination (link-local choice depends on source address). Similarly, for IPv4, split into address we assign and address we observe, and use the address we observe as destination - introduce a clock_gettime() syscall right after epoll_wait() wakes up, so that we can remove all the other ones and pass the current timestamp to tap and socket handlers -- this is additionally needed by UDP to time out bindings to ephemeral ports and mappings between loopback address and a local address - rename sock_l4_add() to sock_l4(), no semantic changes intended - include <arpa/inet.h> in passt.c before kernel headers so that we can use <netinet/in.h> macros to check IPv6 address types, and remove a duplicate <linux/ip.h> inclusion Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Avoid SO_ACCEPTCONN getsockopt() by noting listening/data sockets numbersStefano Brivio2021-04-291-0/+19
| | | | | | | ...the rest is reshuffling existing macros to use the bits we need in TCP code. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Run in background, add message logging with severitiesStefano Brivio2021-03-181-0/+10
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: New design and implementation with native Layer 4 socketsStefano Brivio2021-02-161-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* passt: Add IPv6 and NDP support, further fixes for IPv4 CTStefano Brivio2021-02-161-0/+1
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* merd: ARP and DHCP handlers, connection tracking fixesStefano Brivio2021-02-161-0/+2
With this, merd provides a fully functional IPv4 environment to guests, requiring a single capability, CAP_NET_RAW. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>