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* tcp: Rework window handling, timers, add SO_RCVLOWAT and pools for sockets/pipesStefano Brivio2021-09-272-458/+727
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This introduces a number of fundamental changes that would be quite messy to split. Summary: - advertised window scaling can be as big as we want, we just need to clamp window sizes to avoid exceeding the size of our "discard" buffer for unacknowledged data from socket - add macros to compare sequence numbers - force sending ACK to guest/tap on PSH segments, always in pasta mode, whenever we see an overlapping segment, or when we reach a given threshold compared to our window - we don't actually use recvmmsg() here, fix comments and label - introduce pools for pre-opened sockets and pipes, to decrease latency on new connections - set receiving and sending buffer sizes to the maximum allowed, kernel will clamp and round appropriately - defer clean-up of spliced and non-spliced connection to timer - in tcp_send_to_tap(), there's no need anymore to keep a large buffer, shrink it down to what we actually need - introduce SO_RCVLOWAT setting and activity tracking for spliced connections, to coalesce data moved by splice() calls as much as possible - as we now have a compacted connection table, there's no need to keep sparse bitmaps tracking connection activity -- simply go through active connections with a loop in the timer handler - always clamp the advertised window to half our sending buffer, too, to minimise retransmissions from the guest/tap - set TCP_QUICKACK for originating socket in spliced connections, there's no need to delay them - fix up timeout for unacknowledged data from socket Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Drop TODO about sequence collision attacksStefano Brivio2021-09-271-1/+0
| | | | | | | A random initial sequence number based on a secret has already been there for a while. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tap: Don't leak file descriptor used to bring up loopback interfaceStefano Brivio2021-09-271-6/+11
| | | | | | ...and while at it, set the socket as non-blocking directly on open(). Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tap: Fix comment for tap_sock_init_tun_ns()Stefano Brivio2021-09-271-1/+1
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tap: Bring up tap device too, configure previous MAC address if anyStefano Brivio2021-09-271-2/+74
| | | | | | | In case we need to reinitialise the tap interface, make that relatively transparent to processes running in the namespace. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pcap: Drop O_DSYNC from pcap file descriptorStefano Brivio2021-09-271-1/+1
| | | | | | | passt is stable enough, and dropping O_DSYNC makes reduces the impact of capturing packets on timing, while running tests. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pcap: Don't make pcap files world-readableStefano Brivio2021-09-271-1/+1
| | | | | | | Even if it's just a debugging feature, it's not nice to leak packets to everybody around. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pcap: Don't reinitialise packet capture if we already have oneStefano Brivio2021-09-271-1/+1
| | | | | | | | If the guest disconnects, and a given name (without timestamp) for the pcap file is passed, we would otherwise lose the packets captured until that point. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Actually initialise timers for protocol handlersStefano Brivio2021-09-271-2/+16
| | | | | | | The initial timestamp was not initialised, so timers for protocol handlers wouldn't run at all sometimes. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* ndp: Set router lifetime to 9000s instead of 3600sStefano Brivio2021-09-271-1/+1
| | | | | | | | | | Seen while testing: lifetime expires while we're flooding a tap interface with UDP packets, the router advertisement comes too late, and the kernel drops the default router in the namespace. This should only affect testing, so go for the maximum allowed value, that is, 9000 seconds. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tap: Completely de-serialise input message batchesStefano Brivio2021-09-277-266/+435
| | | | | | | | | | | | | Until now, messages would be passed to protocol handlers in a single batch only if they happened to be dequeued in a row. Packets interleaved between different connections would result in multiple calls to the same protocol handler for a single connection. Instead, keep track of incoming packet descriptors, arrange them in sequences, and call protocol handlers only as we completely sorted input messages in batches. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* conf: Actually zero-terminate DNS and search list arraysStefano Brivio2021-09-271-6/+11
| | | | | | This worked pretty much by chance until now. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Align pkt_buf to PAGE_SIZE (start and size), try to fit in huge pagesStefano Brivio2021-09-274-3/+10
| | | | | | | | | 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>
* README: pasta mode, CI, performance, updated links, etc.Stefano Brivio2021-09-271-66/+185
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* Makefile: Visually separate CFLAGS from input files in resulting cc commandsStefano Brivio2021-09-271-2/+4
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* udp: Switch to new socket message after 32KiB instead of 64KiBStefano Brivio2021-09-271-2/+2
| | | | | | | For some reason, this measurably improves performance with qemu and virtio-net. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* udp: Decrease UDP_TAP_FRAMES to 16Stefano Brivio2021-09-271-1/+1
| | | | | | | Similarly to the decrease in TCP_TAP_FRAMES, this improves fairness, with a very small impact on performance. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Decrease TCP_TAP_FRAMES to 8Stefano Brivio2021-09-271-1/+1
| | | | | | This significantly improves fairness in serving concurrent connections. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta, tcp: Update comment about spliced connection statesStefano Brivio2021-09-271-1/+4
| | | | | | ...we now have SPLICE_FIN_{FROM,TO,BOTH} too. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Increase TAP_BUF_BYTES to 256 maximum-sized descriptorsStefano Brivio2021-09-191-1/+1
| | | | | | ...this actually improves performance. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* README: Source jsStefano Brivio2021-09-181-0/+8
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Don't reset connection from ESTABLISHED state on EPOLLHUPStefano Brivio2021-09-161-6/+1
| | | | | | | | | | | That might just mean we shut down the socket -- but we still have to go through the other states to ensure a orderly shutdown guest-side. While at it, drop the EPOLLHUP check for unhandled states: we should never hit that, but if we do, resetting the connection at that point is probably the wrong thing to do. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta, tcp: Mask EPOLLIN and EPOLLRDHUP after sending FINStefano Brivio2021-09-161-2/+14
| | | | | | | Now that we dropped EPOLLET, we'll keep getting EPOLLRDHUP, and possibly EPOLLIN, even if there's nothing to read anymore. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta, tcp: Break splice() loop once we've written everything that was readStefano Brivio2021-09-161-2/+7
| | | | | | That's a guarantee that we don't need to retry writing. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta, tcp: Don't set SPLICE_FIN_BOTH state on EPOLLHUPStefano Brivio2021-09-161-3/+1
| | | | | | | EPOLLHUP just means we shut down one side of the connection on *one* socket: remember, we have two sockets here. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta, tcp: Don't reset 'never_read' flag on write retriesStefano Brivio2021-09-161-2/+3
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta, tcp: Don't set TCP_CORK on spliced socketsStefano Brivio2021-09-161-6/+1
| | | | | | | | ...throughput isn't everything: this leads (of course) to horrible latency with small, sparse messages. As a consequence, there's no need to set TCP_NODELAY either. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Fix setting window from maximum ACK sequence in batchStefano Brivio2021-09-161-6/+2
| | | | | | | | | If we're at the first message in a batch, it's safe to get the window value from it, and there's no need to subtract anything for a comparison on that's not even done -- we'll override it later in any case if we find messages with a higher ACK sequence number. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta, tcp: Set pipe descriptor numbers to -1 after closingStefano Brivio2021-09-161-0/+4
| | | | | | ...so that we don't try to close them again, even if harmless. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta, tcp: Drop EPOLLET for spliced, established connectionsStefano Brivio2021-09-161-5/+5
| | | | | | | ...tcp_handler_splice() doesn't guarantee we read all the available data, the sending buffer might be full. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Read SO_SNDBUF unconditionallyStefano Brivio2021-09-161-17/+11
| | | | | | | | Checking it only when the cached value is smaller than the current window of the receiver is not enough: it might shrink further while the receiver window is growing. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta: Clean up FIN connection flags once a connection is deletedStefano Brivio2021-09-151-0/+1
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta: Set spliced connection flag in epoll reference on compactionStefano Brivio2021-09-151-2/+2
| | | | | | ...otherwise, we'll mix indices with non-spliced connections. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta: Clean up namespace processes on exit, reap zombies from clone()Stefano Brivio2021-09-151-9/+83
| | | | | | | | | | | | If pasta created the namespace, it's probably expected that processes started in the same namespace are terminated once pasta exits. Scan procfs namespace links for corresponding processes, send SIGQUIT and SIGKILL (after one second) if found. While at it, make the signal handler reap otherwise-zombies resulting from clone(). Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* checksum: Add checksum.hStefano Brivio2021-09-141-0/+5
| | | | | | I forgot to commit this. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Request retransmission with updated sequence also on partial write to ↵Stefano Brivio2021-09-141-11/+8
| | | | | | | | | | | socket If we couldn't write the whole batch of received packets to the socket, and we have missing segments, we still need to request their retransmission right away, otherwise it will take ages for the guest to figure out we're missing them. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: In ESTABLISHED state, acknowledge segments as they're sent to the socketStefano Brivio2021-09-141-6/+15
| | | | | | | | | ...instead of waiting for the remote peer to do that -- it's especially important in case we request retransmissions from the guest, but it also helps speeding up slow start. This should probably be a configurable behaviour in the future. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Properly time out ACK wait from tapStefano Brivio2021-09-141-3/+3
| | | | | | | | | Seen with iperf3: a control connection is established, no data flows for a while, all segments are acknowledged. The socket starts closing it, and we immediately time out because the last ACK from tap was one minute before that. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Don't mistake a FIN segment with no data for a Fast Retransmit requestStefano Brivio2021-09-141-1/+2
| | | | | | | It carries no data and usually duplicates the previous ACK sequence, but it's just a FIN. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Check errno on sendmmsg() failure, not just the return valueStefano Brivio2021-09-141-1/+1
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Make sure sending window is initialised before sending to tapStefano Brivio2021-09-141-1/+1
| | | | | | | Seen with iperf3: the first packet from socket (data connection) is 65520 bytes and doesn't fit in the window. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* qrap: Set x-txburst as temporary workaround for virtio-net TX stallStefano Brivio2021-09-091-1/+1
| | | | | | | | Flooding a virtio-net interface connected to a socket back-end results in a TX stall I'm still debugging. The stall goes away by setting a higher value for x-txburst (256 by default). Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* udp: Reset iov_base after sending partial message on sendmmsg() failureStefano Brivio2021-09-091-0/+2
| | | | | | | We set the length while processing messges, but the starting address is pre-initialised. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* udp: Fix comparison of seen IPv4 address for local connectionsStefano Brivio2021-09-091-1/+2
| | | | | | c->addr4_seen is stored in network order. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp: Fixes for closing states, spliced connections, out-of-order packets, etc.Stefano Brivio2021-09-091-207/+400
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This fixes a number of issues found with some heavier testing with uperf and neper: - in most closing states, we can still accept data, check for EPOLLIN when appropriate - introduce a new state, ESTABLISHED_SOCK_FIN_SENT, to track the fact we already sent a FIN segment to the tap device, for proper sequence number bookkeeping - for pasta mode only: spliced connections also need tracking of (inferred) FIN segments and clean half-pipe shutdowns - streamline resetting epoll_wait bitmaps with a new function, tcp_tap_epoll_mask(), instead of repeating the logic all over the place - set EPOLLET for tap connections too, whenever we are waiting for EPOLLRDHUP or an event from the tap to proceed with data transfer, to avoid useless loops with EPOLLIN set - impose an additional limit on the sending window advertised to the guest, given by SO_SNDBUF: it makes no sense to completely fill the sending buffer and send a zero window: stop a bit before we hit that - handle *all* interrupted system calls as needed - simplify the logic for reordering of out-of-order segments received from tap: it's not a corner case, and the previous logic allowed for deadloops - fix comparison of seen IPv4 address when we get a new connection from a socket directed to the configured guest address Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tap: Fix calculation of number of tap scatter-gather IO messagesStefano Brivio2021-09-091-2/+3
| | | | | | Messages are typically smaller than ETH_MAX_MTU. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta: Set ping_group_range upon namespace creationStefano Brivio2021-09-091-0/+4
| | | | | | | ...this allows processes running as the only group available in the namespace to create ICMP Echo sockets. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Add epoll event indication and passt/pasta mode in socket debug messageStefano Brivio2021-09-091-1/+3
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* conf: Fix help message about default behaviour for UDP port forwardingStefano Brivio2021-09-091-6/+4
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* conf, dhcp, ndp: Fix message about default MTU, make NDP consistentStefano Brivio2021-09-093-4/+16
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
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