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* udp: Pre-populate msg_names with local addressDavid Gibson2023-01-131-0/+7
| | | | | | | | | | | udp_splice_namebuf is now used only for spliced sending, and so it is only ever populated with the localhost address, either IPv4 or IPv6. So, replace the awkward initialization in udp_sock_handler_splice() with statically initialized versions for IPv4 and IPv6. We then just need to update the port number in udp_sock_handler_splice(). Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* util, pasta: Add do_clone() wrapper around __clone2() and clone()Stefano Brivio2022-11-161-3/+5
| | | | | | | | | | | | | | | Spotted in Debian's buildd logs: on ia64, clone(2) is not available: the glibc wrapper is named __clone2() and it takes, additionally, the size of the stack area passed by the caller. Add a do_clone() wrapper handling the different cases, and also taking care of pointing the child's stack in the middle of the allocated area: on PA-RISC (hppa), handled by clone(), the stack grows up, and on ia64 the stack grows down, but the register backing store grows up -- and I think it might be actually used here. Suggested-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* Use typing to reduce chances of IPv4 endianness errorsDavid Gibson2022-11-041-2/+10
| | | | | | | | | | | | | | | | | | | We recently corrected some errors handling the endianness of IPv4 addresses. These are very easy errors to make since although we mostly store them in network endianness, we sometimes need to manipulate them in host endianness. To reduce the chances of making such mistakes again, change to always using a (struct in_addr) instead of a bare in_addr_t or uint32_t to store network endian addresses. This makes it harder to accidentally do arithmetic or comparisons on such addresses as if they were host endian. We introduce a number of IN4_IS_ADDR_*() helpers to make it easier to directly work with struct in_addr values. This has the additional benefit of making the IPv4 and IPv6 paths more visually similar. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* util: Set NS_FN_STACK_SIZE to one eighth of ulimit-reported maximum stack size2022_10_22.b68da10Stefano Brivio2022-10-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ...instead of one fourth. On the main() -> conf() -> nl_sock_init() call path, LTO from gcc 12 on (at least) x86_64 decides to inline... everything: nl_sock_init() is effectively part of main(), after commit 3e2eb4337bc0 ("conf: Bind inbound ports with CAP_NET_BIND_SERVICE before isolate_user()"). This means we exceed the maximum stack size, and we get SIGSEGV, under any condition, at start time, as reported by Andrea on a recent build for CentOS Stream 9. The calculation of NS_FN_STACK_SIZE, which is the stack size we reserve for clones, was previously obtained by dividing the maximum stack size by two, to avoid an explicit check on architecture (on PA-RISC, also known as hppa, the stack grows up, so we point the clone to the middle of this area), and then further divided by two to allow for any additional usage in the caller. Well, if there are essentially no function calls anymore, this is not enough. Divide it by eight, which is anyway much more than possibly needed by any clone()d callee. I think this is robust, so it's a fix in some sense. Strictly speaking, though, we have no formal guarantees that this isn't either too little or too much. What we should do, eventually: check cloned() callees, there are just thirteen of them at the moment. Note down any stack usage (they are mostly small helpers), bonus points for an automated way at build time, quadruple that or so, to allow for extreme clumsiness, and use as NS_FN_STACK_SIZE. Perhaps introduce a specific condition for hppa. Reported-by: Andrea Bolognani <abologna@redhat.com> Fixes: 3e2eb4337bc0 ("conf: Bind inbound ports with CAP_NET_BIND_SERVICE before isolate_user()") Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* Replace FWRITE with a functionDavid Gibson2022-10-151-12/+1
| | | | | | | | | | | | | | In a few places we use the FWRITE() macro to open a file, replace it's contents with a given string and close it again. There's no real reason this needs to be a macro rather than just a function though. Turn it into a function 'write_file()' and make some ancillary cleanups while we're there: - Add a return code so the caller can handle giving a useful error message - Handle the case of short write()s (unlikely, but possible) - Add O_TRUNC, to make sure we replace the existing contents entirely Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* util.h: Add missing gcc pragma push before pragma popStefano Brivio2022-10-151-0/+1
| | | | | | | | | While building with clang: ./util.h:176:24: warning: pragma diagnostic pop could not pop, no matching push [-Wunknown-pragmas] Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
* Don't create 'tap' socket for ports that are bound to loopback onlyStefano Brivio2022-10-151-0/+3
| | | | | | | | | | | | | | | | | | | | | If the user specifies an explicit loopback address for a port binding, we're going to use that address for the 'tap' socket, and the same exact address for the 'spliced' socket (because those are, by definition, only bound to loopback addresses). This means that the second binding will fail, and, unexpectedly, the port is forwarded, but via tap device, which means the source address in the namespace won't be a loopback address. Make it explicit under which conditions we're creating which kind of socket, by refactoring tcp_sock_init() into two separate functions for IPv4 and IPv6 and gathering those conditions at the beginning. Also, don't create spliced sockets if the user specifies explicitly a non-loopback address, those are harmless but not desired either. Fixes: 3c6ae625101a ("conf, tcp, udp: Allow address specification for forwarded ports") Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* conf, tcp, udp: Allow specification of interface to bind toStefano Brivio2022-10-151-1/+2
| | | | | | | | | | | | | | | | Since kernel version 5.7, commit c427bfec18f2 ("net: core: enable SO_BINDTODEVICE for non-root users"), we can bind sockets to interfaces, if they haven't been bound yet (as in bind()). Introduce an optional interface specification for forwarded ports, prefixed by %, that can be passed together with an address. Reported use case: running local services that use ports we want to have externally forwarded: https://github.com/containers/podman/issues/14425 Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
* conf, log, Makefile: Add versioning informationStefano Brivio2022-10-151-0/+8
| | | | | | | Add a --version option displaying that, and also include this information in the log files. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* Move logging functions to a new file, log.cStefano Brivio2022-10-141-16/+0
| | | | | | | | Logging to file is going to add some further complexity that we don't want to squeeze into util.c. Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
* udp: Replace pragma to ignore bogus stringop-overread warning with workaroundStefano Brivio2022-09-291-23/+0
| | | | | | | | | | | | | | | | | | | Commit c318ffcb4c93 ("udp: Ignore bogus -Wstringop-overread for write() from gcc 12.1") uses a gcc pragma to ignore a bogus warning, which started appearing on gcc 12.1 (aarch64 and x86_64) due to: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103483 ...but gcc 12.2 has the same issue. Not just that: if LTO is enabled, the pragma itself is ignored (this wasn't the case with gcc 12.1), because of: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80922 Drop the pragma, and assign a frame (in the networking sense) pointer from the offset of the Ethernet header in the buffer, then pass it to write() and pcap(), so that gcc doesn't obsess anymore with the fact that an Ethernet header is 14 bytes and we're sending more than that. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* cppcheck: Use inline suppression for ffsl()David Gibson2022-09-291-0/+1
| | | | | | | | | | We define our own ffsl() as a weak symbol, in case our C library doesn't include it. On glibc systems which *do* include it, this causes a cppcheck warning because unsurprisingly our version doesn't pick the same argument names. Convert the suppression for this into an inline suppression. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* Move self-isolation code into a separate fileDavid Gibson2022-09-131-2/+0
| | | | | | | | passt/pasta contains a number of routines designed to isolate passt from the rest of the system for security. These are spread through util.c and passt.c. Move them together into a new isolation.c file. Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
* Consolidate determination of UID/GID to run asDavid Gibson2022-09-131-1/+0
| | | | | | | | | | | | Currently the logic to work out what UID and GID we will run as is spread across conf(). If --runas is specified it's handled in conf_runas(), otherwise it's handled by check_root(), which depends on initialization of the uid and gid variables by either conf() itself or conf_runas(). Make this clearer by putting all the UID and GID logic into a single conf_ugid() function. Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
* Split checking for root from dropping root privilegeDavid Gibson2022-09-131-0/+1
| | | | | | | | | | | | | | | | | | check_root() both checks to see if we are root (in the init namespace), and if we are drops to an unprivileged user. To make future cleanups simpler, split the checking for root (now in check_root()) from the actual dropping of privilege (now in drop_root()). Note that this does slightly alter semantics. Previously we would only setuid() if we were originally root (in the init namespace). Now we will always setuid() and setgid(), though it won't actually change anything if we weren't privileged to begin with. This also means that we will now always attempt to switch to the user specified with --runas, even if we aren't (init namespace) root to begin with. Obviously this will fail with an error if we weren't privileged to start with. --help and the man page are updated accordingly. Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
* Don't store UID & GID persistently in the context structureDavid Gibson2022-09-131-1/+1
| | | | | | | | c->uid and c->gid are first set in conf(), and last used in check_root() itself called from conf(). Therefore these don't need to be fields in the long lived context structure and can instead be locals in conf(). Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
* Clarify semantics of c->v4 and c->v6 variablesDavid Gibson2022-07-301-6/+0
| | | | | | | | | | | | | | | | | | | | | The v4 and v6 fields of the context structure can be confusing, because they change meaning part way through the code: Before conf_ip(), they are booleans which indicate whether the -4 or -6 options have been given. After conf_ip() they are DISABLED|ENABLED|PROBE enums which indicate whether the IP version is available (which means both that it was allowed on the command line and we were able to configure it). The PROBE variant of the enum is only used locally within conf_ip() and since recent changes there it no longer has a real purpose different from ENABLED. Simplify this all by making the context fields always just a boolean indicating the availability of the IP version. They both default to 1, but can be set to 0 by either command line options or configuration failures. We use some local variables in conf() for tracking the state of the command line options on their own. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> [sbrivio: Minor coding style fix in conf.c] Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* conf: Add --runas option, changing to given UID and GID if started as rootStefano Brivio2022-05-191-0/+1
| | | | | | | | | | | | | | On some systems, user and group "nobody" might not be available. The new --runas option allows to override the default "nobody" choice if started as root. Now that we allow this, drop the initgroups() call that was used to add any additional groups for the given user, as that might now grant unnecessarily broad permissions. For instance, several distributions have a "kvm" group to allow regular user access to /dev/kvm, and we don't need that in passt or pasta. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* udp: Ignore bogus -Wstringop-overread for write() from gcc 12.1Stefano Brivio2022-05-191-0/+23
| | | | | | | | | | | | | | | | | With current OpenSUSE Tumbleweed on aarch64 (gcc-12-1.3.aarch64) and on x86_64 (gcc-12-1.4.x86_64), but curiously not on armv7hl (gcc-12-1.3.armv7hl), gcc warns about using the _pointer_ to the 802.3 header to write the whole frame to the tap descriptor: reading between 62 and 4294967357 bytes from a region of size 14 which is bogus: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103483 Probably declaring udp_sock_fill_data_v{4,6}() as noinline would "fix" this, but that's on the data path, so I'd rather not. Use a gcc pragma instead. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* conf, tcp, udp: Allow address specification for forwarded portsStefano Brivio2022-05-011-9/+2
| | | | | | | | | | | | | This feature is available in slirp4netns but was missing in passt and pasta. Given that we don't do dynamic memory allocation, we need to bind sockets while parsing port configuration. This means we need to process all other options first, as they might affect addressing and IP version support. It also implies a minor rework of how TCP and UDP implementations bind sockets. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* treewide: Argument cannot be negative, CWE-687Stefano Brivio2022-04-071-0/+12
| | | | | | Actually harmless. Reported by Coverity. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* treewide: Mark constant references as constStefano Brivio2022-03-291-4/+4
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* treewide: Add include guardsStefano Brivio2022-03-291-0/+5
| | | | | | | ...at the moment, just for consistency with packet.h, icmp.h, tcp.h and udp.h. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* treewide: Packet abstraction with mandatory boundary checksStefano Brivio2022-03-291-1/+4
| | | | | | | | | | | | | | | | | | | | 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>
* tcp: Refactor to use events instead of states, split out spliced implementationStefano Brivio2022-03-281-1/+3
| | | | | | | | | | | | | | | | | | | | | Using events and flags instead of states makes the implementation much more straightforward: actions are mostly centered on events that occurred on the connection rather than states. An example is given by the ESTABLISHED_SOCK_FIN_SENT and FIN_WAIT_1_SOCK_FIN abominations: we don't actually care about which side started closing the connection to handle closing of connection halves. Split out the spliced implementation, as it has very little in common with the "regular" TCP path. Refactor things here and there to improve clarity. Add helpers to trace where resets and flag settings come from. No functional changes intended. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* util: Use standard int typesStefano Brivio2022-03-251-6/+6
| | | | | | ...instead of kernel-like short notations. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* util: Drop CHECK_SET_MIN_MAX{,_PROTO_FD} macrosStefano Brivio2022-03-251-14/+0
| | | | | | | ...those were used when epoll references used to be socket numbers, they should have gone away a long time ago. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* conf, util, tap: Implement --trace option for extra verbose loggingStefano Brivio2022-03-251-0/+8
| | | | | | | | --debug can be a bit too noisy, especially as single packets or socket messages are logged: implement a new option, --trace, implying --debug, that enables all debug messages. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt, pasta: Namespace-based sandboxing, defer seccomp policy applicationStefano Brivio2022-02-211-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To reach (at least) a conceptually equivalent security level as implemented by --enable-sandbox in slirp4netns, we need to create a new mount namespace and pivot_root() into a new (empty) mountpoint, so that passt and pasta can't access any filesystem resource after initialisation. While at it, also detach IPC, PID (only for passt, to prevent vulnerabilities based on the knowledge of a target PID), and UTS namespaces. With this approach, if we apply the seccomp filters right after the configuration step, the number of allowed syscalls grows further. To prevent this, defer the application of seccomp policies after the initialisation phase, before the main loop, that's where we expect bad things to happen, potentially. This way, we get back to 22 allowed syscalls for passt and 34 for pasta, on x86_64. While at it, move #syscalls notes to specific code paths wherever it conceptually makes sense. We have to open all the file handles we'll ever need before sandboxing: - the packet capture file can only be opened once, drop instance numbers from the default path and use the (pre-sandbox) PID instead - /proc/net/tcp{,v6} and /proc/net/udp{,v6}, for automatic detection of bound ports in pasta mode, are now opened only once, before sandboxing, and their handles are stored in the execution context - the UNIX domain socket for passt is also bound only once, before sandboxing: to reject clients after the first one, instead of closing the listening socket, keep it open, accept and immediately discard new connection if we already have a valid one Clarify the (unchanged) behaviour for --netns-only in the man page. To actually make passt and pasta processes run in a separate PID namespace, we need to unshare(CLONE_NEWPID) before forking to background (if configured to do so). Introduce a small daemon() implementation, __daemon(), that additionally saves the PID file before forking. While running in foreground, the process itself can't move to a new PID namespace (a process can't change the notion of its own PID): mention that in the man page. For some reason, fork() in a detached PID namespace causes SIGTERM and SIGQUIT to be ignored, even if the handler is still reported as SIG_DFL: add a signal handler that just exits. We can now drop most of the pasta_child_handler() implementation, that took care of terminating all processes running in the same namespace, if pasta started a shell: the shell itself is now the init process in that namespace, and all children will terminate once the init process exits. Issuing 'echo $$' in a detached PID namespace won't return the actual namespace PID as seen from the init namespace: adapt demo and test setup scripts to reflect that. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Address new clang-tidy warnings from LLVM 13.0.1Stefano Brivio2022-01-301-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | clang-tidy from LLVM 13.0.1 reports some new warnings from these checkers: - altera-unroll-loops, altera-id-dependent-backward-branch: ignore for the moment being, add a TODO item - bugprone-easily-swappable-parameters: ignore, nothing to do about those - readability-function-cognitive-complexity: ignore for the moment being, add a TODO item - altera-struct-pack-align: ignore, alignment is forced in protocol headers - concurrency-mt-unsafe: ignore for the moment being, add a TODO item Fix bugprone-implicit-widening-of-multiplication-result warnings, though, that's doable and they seem to make sense. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp, udp, util: Fixes for bitmap handling on big-endian, castsStefano Brivio2022-01-261-0/+2
| | | | | | | | Bitmap manipulating functions would otherwise refer to inconsistent sets of bits on big-endian architectures. While at it, fix up a couple of casts. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* util: Fall-back definitions for SECCOMP_RET_KILL_PROCESS, ETH_{MAX,MIN}_MTUStefano Brivio2022-01-261-0/+10
| | | | | | They're not available on some older toolchains. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Drop <linux/ipv6.h> include, carry own ipv6hdr and opt_hdr definitionsStefano Brivio2022-01-261-0/+28
| | | | | | | This is the only remaining Linux-specific include -- drop it to avoid clang-tidy warnings and to make code more portable. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Fix build with gcc 7, use std=c99, enable some more Clang checkersStefano Brivio2021-10-211-2/+1
| | | | | | | | | | | | | | Unions and structs, you all have names now. Take the chance to enable bugprone-reserved-identifier, cert-dcl37-c, and cert-dcl51-cpp checkers in clang-tidy. Provide a ffsl() weak declaration using gcc built-in. Start reordering includes, but that's not enough for the llvm-include-order checker yet. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Add clang-tidy Makefile target and test, take care of warningsStefano Brivio2021-10-201-3/+3
| | | | | | | Most are just about style and form, but a few were actually serious mistakes (NDP-related). Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* LICENSES: Add license text files, add missing notices, fix SPDX tagsStefano Brivio2021-10-201-0/+5
| | | | | | | | | | SPDX tags don't replace license files. Some notices were missing and some tags were not according to the SPDX specification, too. Now reuse --lint from the REUSE tool (https://reuse.software/) passes. Reported-by: Martin Hauke <mardnh@gmx.de> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Static builds: don't redefine __vsyslog(), skip getpwnam() and ↵Stefano Brivio2021-10-161-1/+1
| | | | | | initgroups() Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* util: Define ROUND_UP()Stefano Brivio2021-10-151-0/+2
| | | | | | | ...not actually used, just for completeness, as ROUND_DOWN() is defined. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt, pasta: Completely avoid dynamic memory allocationStefano Brivio2021-10-141-0/+5
| | | | | | | | | Replace libc functions that might dynamically allocate memory with own implementations or wrappers. Drop brk(2) from list of allowed syscalls in seccomp profile. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* conf, tap: Split netlink and pasta functions, allow interface configurationStefano Brivio2021-10-141-0/+9
| | | | | | | | | | Move netlink routines to their own file, and use netlink to configure or fetch all the information we need, except for the TUNSETIFF ioctl. Move pasta-specific functions to their own file as well, add parameters and calls to configure the tap interface in the namespace. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta: Allow specifying paths and names of namespacesGiuseppe Scrivano2021-10-071-1/+1
| | | | | | | | | | | | | | | | | | Based on a patch from Giuseppe Scrivano, this adds the ability to: - specify paths and names of target namespaces to join, instead of a PID, also for user namespaces, with --userns - request to join or create a network namespace only, without entering or creating a user namespace, with --netns-only - specify the base directory for netns mountpoints, with --nsrun-dir Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com> [sbrivio: reworked logic to actually join the given namespaces when they're not created, implemented --netns-only and --nsrun-dir, updated pasta demo script and man page] Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp, tap: Turn tcp_probe_mem() into sock_probe_mem(), use for AF_UNIX socket tooStefano Brivio2021-10-051-0/+5
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* conf, tcp: Periodic detection of bound ports for pasta port forwardingStefano Brivio2021-09-271-1/+1
| | | | | | | | | | Detecting bound ports at start-up time isn't terribly useful: do this periodically instead, if configured. This is only implemented for TCP at the moment, UDP is somewhat more complicated: leave a TODO there. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Align pkt_buf to PAGE_SIZE (start and size), try to fit in huge pagesStefano Brivio2021-09-271-0/+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>
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