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* tcp: Actually enforce MAX_CONNS limitStefano Brivio2021-05-211-1/+1
| | | | | | | | | | | | | | and, given that the connection table is indexed by socket number, we also need to increase MAX_CONNS now as the ICMP implementation needs 2^17 sockets, that will be opened before TCP connections are accepted. This needs to be changed later: the connection table should be indexed by a translated number -- we're wasting 2^17 table entries otherwise. Move initialisation of TCP listening sockets as last per-protocol initialisation, this will make it easier. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Close UNIX domain socket on failure before accepting new connectionsStefano Brivio2021-05-211-1/+3
| | | | | | | | The socket isn't necessarily closed, make sure we close it before getting a new one from accept(), so that we don't mix it up with protocol sockets numbering. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Introduce packet capture implementationStefano Brivio2021-05-211-0/+5
| | | | | | | | With -DDEBUG, passt now saves guest-side traffic captures in pcap format at /tmp/passt_<ISO8601 timestamp>.pcap. The timestamp refers to time and date of start-up. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* dhcp, ndp, dhcpv6: Support for multiple DNS servers, search listStefano Brivio2021-05-211-20/+57
| | | | | | | | | | | 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>
* passt: With -DDEBUG, also print protocol number for unsupported protocolsStefano Brivio2021-05-211-5/+5
| | | | | | | ...otherwise, we have no idea what's going on if we receive something unexpected. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Don't fork into background until the UNIX domain socket isn't listeningStefano Brivio2021-05-101-4/+7
| | | | | | | | Once passt forks to background, it should be guaranteed that the UNIX domain socket is available, otherwise, if qemu is started right after it, it might fail to connect. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Keep just two arrays to print context IPv4 and IPv6 addressesStefano Brivio2021-05-101-9/+9
| | | | | | | | Multiple arrays, one for each address, were needed with a single fprintf(). Now that it's replaced by info(), we can have just one for each protocol version. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Don't use getprotobynumber() in debug buildStefano Brivio2021-05-101-3/+17
| | | | | | | | | With glibc, we can't reliably build a static binary with getprotobynumber(), which is currently used with -DDEBUG. Replace that with a small array of protocol strings. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* udp, passt: Introduce socket packet buffer, avoid getsockname() for UDPStefano Brivio2021-04-301-7/+8
| | | | | | | | | | 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 Brivio2021-04-291-39/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 Brivio2021-04-291-26/+25
| | | | | | | ...the rest is reshuffling existing macros to use the bits we need in TCP code. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Spare some syscalls, add some optimisations from profilingStefano Brivio2021-04-231-44/+69
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid a bunch of syscalls on forwarding paths by: - storing minimum and maximum file descriptor numbers for each protocol, fall back to SO_PROTOCOL query only on overlaps - allocating a larger receive buffer -- this can result in more coalesced packets than sendmmsg() can take (UIO_MAXIOV, i.e. 1024), so make sure we don't exceed that within a single call to protocol tap handlers - nesting the handling loop in tap_handler() in the receive loop, so that we have better chances of filling our receive buffer in fewer calls - skipping the recvfrom() in the UDP handler on EPOLLERR -- there's nothing to be done in that case and while at it: - restore the 20ms timer interval for periodic (TCP) events, I accidentally changed that to 100ms in an earlier commit - attempt using SO_ZEROCOPY for UDP -- if it's not available, sendmmsg() will succeed anyway - fix the handling of the status code from sendmmsg(), if it fails, we'll try to discard the first message, hence return 1 from the UDP handler Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Don't unconditionally disable forking to backgroundStefano Brivio2021-04-221-1/+1
| | | | | | | ...I left this there by mistake while debugging the debug stuff. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Introduce packet batching mechanismStefano Brivio2021-04-221-69/+215
| | | | | | | | | | Receive packets in batches from AF_UNIX, check if they can be sent with a single syscall, and batch them up with sendmmsg() in case. A bit rudimentary, currently only implemented for UDP, but it seems to work. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Print ports in debug messages only for protocols with portsStefano Brivio2021-04-221-2/+5
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Always use INET_ADDRSTRLEN/INET6_ADDRSTRLEN for inet_ntop() buffersStefano Brivio2021-04-211-4/+4
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Make UNIX domain socket world-writable and world-readableStefano Brivio2021-04-131-0/+5
| | | | | | ...save a chmod every time passt is started. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Introduce a DHCPv6 serverStefano Brivio2021-04-131-5/+12
| | | | | | | | | | | | This implementation, similarly to the IPv4 DHCP one, hands out a single address, which is the same as the upstream address for the host. This avoids the need for address translation as long as the client runs a DHCPv6 client. The NDP "Managed" flag is now set in Router Advertisements. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Add libvirt patch for qemu UNIX socket domain back-endStefano Brivio2021-03-211-1/+1
| | | | | | | | | | ...and mention it in the README. While at it, remove useless escaping in the README, and fix indentation in the syslog message with the qemu command line example. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Initialise socket after getting addresses and routesStefano Brivio2021-03-201-5/+9
| | | | | | | | | | ...otherwise, both IPv4 and IPv6 are considered disabled, and nothing works anymore. While at it, don't fork to background on debug builds, and log to stderr too in that case. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Set soft limit for number of open files to hard limitStefano Brivio2021-03-181-0/+12
| | | | | | | | Default value for /proc/sys/fs/nr_open is 2^20, which is more than enough: set this hard limit as current (soft) limit on start, and drop the 'ulimit -n' from the demo script. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Run in background, add message logging with severitiesStefano Brivio2021-03-181-61/+70
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: qemu patch for direct UNIX domain connection without the qrap wrapperStefano Brivio2021-03-181-1/+6
| | | | | | | ...and, while at it, a second patch to fail when connect() fails in turn with EINVAL. These two patches haven't been sent upstream yet. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Introduce ICMP echo proxyStefano Brivio2021-03-181-8/+16
| | | | | | | | It's nice to be able to confirm connectivity using ICMP or ICMPv6 echo requests, and "ping" sockets on Linux (IPPROTO_ICMP datagram) allow us to do that without any special capability. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Use INET{,6}_ADDRSTRLEN instead of open coded sizeofStefano Brivio2021-03-171-2/+2
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Assorted fixes from "fresh eyes" reviewStefano Brivio2021-02-211-74/+74
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A bunch of fixes not worth single commits at this stage, notably: - make buffer, length parameter ordering consistent in ARP, DHCP, NDP handlers - strict checking of buffer, message and option length in DHCP handler (a malicious client could have easily crashed it) - set up forwarding for IPv4 and IPv6, and masquerading with nft for IPv4, from demo script - get rid of separate slow and fast timers, we don't save any overhead that way - stricter checking of buffer lengths as passed to tap handlers - proper dequeuing from qemu socket back-end: I accidentally trashed messages that were bundled up together in a single tap read operation -- the length header tells us what's the size of the next frame, but there's no apparent limit to the number of messages we get with one single receive - rework some bits of the TCP state machine, now passive and active connection closes appear to be robust -- introduce a new FIN_WAIT_1_SOCK_FIN state indicating a FIN_WAIT_1 with a FIN flag from socket - streamline TCP option parsing routine - track TCP state changes to stderr (this is temporary, proper debugging and syslogging support pending) - observe that multiplying a number by four might very well change its value, and this happens to be the case for the data offset from the TCP header as we check if it's the same as the total length to find out if it's a duplicated ACK segment - recent estimates suggest that the duration of a millisecond is closer to a million nanoseconds than a thousand of them, this trend is now reflected into the timespec_diff_ms() convenience routine Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: New design and implementation with native Layer 4 socketsStefano Brivio2021-02-161-561/+134
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 Brivio2021-02-161-77/+425
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* merd: Rename to PASSTStefano Brivio2021-02-161-0/+666
Plug A Simple Socket Transport. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
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