- dev - passt

[PATCH 2/2] pasta: Clean up waiting pasta child on failures
by David Gibson 12 Dec '25

12 Dec '25

When pasta is invoked with a command rather than an existing namespace to attach to, it spawns a child process to run a shell or other command. We create that process during conf(), since we need the namespace to exist for much of our setup. However, we don't want the specified command to run until the pasta network interface is ready for use. Therefore, pasta_spawn_cmd() executing in the child waits before exec()ing. main() signals the child to continue with SIGUSR1 shortly before entering the main forwarding loop. This has the downside that if we exit due to any kind of failure between conf() and the SIGUSR1, the child process will be around waiting indefinitely. The user must manually clean this up. Make this cleaner, by having passt_exit() terminate the child, when called during this window. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- passt.c | 1 + pasta.c | 2 ++ pasta.h | 1 + util.c | 5 +++++ 4 files changed, 9 insertions(+) diff --git a/passt.c b/passt.c index cf38822f..955c7091 100644 --- a/passt.c +++ b/passt.c @@ -431,6 +431,7 @@ int main(int argc, char **argv) if (pasta_child_pid) { kill(pasta_child_pid, SIGUSR1); log_stderr = false; + pasta_child_signalled = true; } isolate_postfork(&c); diff --git a/pasta.c b/pasta.c index 5c693de1..8ac4511f 100644 --- a/pasta.c +++ b/pasta.c @@ -54,6 +54,8 @@ /* PID of child, in case we created a namespace */ int pasta_child_pid; +/* Has the child been signalled to start a shell or command */ +bool pasta_child_signalled; /** * pasta_child_handler() - Exit once shell exits (if we started it), reap clones diff --git a/pasta.h b/pasta.h index 4b063d13..55028c74 100644 --- a/pasta.h +++ b/pasta.h @@ -7,6 +7,7 @@ #define PASTA_H extern int pasta_child_pid; +extern bool pasta_child_signalled; void pasta_open_ns(struct ctx *c, const char *netns); void pasta_start_ns(struct ctx *c, uid_t uid, gid_t gid, diff --git a/util.c b/util.c index e266c396..4744f09e 100644 --- a/util.c +++ b/util.c @@ -35,6 +35,7 @@ #include "log.h" #include "pcap.h" #include "epoll_ctl.h" +#include "pasta.h" #ifdef HAS_GETRANDOM #include <sys/random.h> #endif @@ -1235,6 +1236,10 @@ void abort_with_msg(const char *fmt, ...) */ void passt_exit(int status) { + /* If we're starting our own namespace, don't leave it in limbo */ + if (pasta_child_pid && !pasta_child_signalled) + kill(pasta_child_pid, SIGTERM); + /* Make sure we don't leave the pcap file truncated */ if (pcap_fd != -1 && fsync(pcap_fd)) warn_perror("Failed to flush pcap file, it might be truncated"); -- 2.52.0

2 4

[PATCH v3 0/6] vhost-user: Add multiqueue support
by Laurent Vivier 11 Dec '25

11 Dec '25

This series implements multiqueue support for vhost-user mode, allowing passt to utilize multiple queue pairs for improved network throughput when used with multi-CPU guest VMs. While this version uses a single thread for packet processing, it enables the guest kernel to distribute network traffic across multiple queues and vCPUs. The implementation advertises support for up to 16 queue pairs (32 virtqueues) by setting VIRTIO_NET_F_MQ and VHOST_USER_PROTOCOL_F_MQ feature flags. Packets are routed to the appropriate RX queue based on which TX queue they originated from, following the virtio specification's automatic receive steering requirements. This series adds: - Multiqueue capability advertisement (VIRTIO_NET_F_MQ and VHOST_USER_PROTOCOL_F_MQ features) - Per-queue-pair packet pools to support concurrent queue operations - Queue pair parameter throughout the network stack, propagated through all protocol handlers (TCP, UDP, ICMP, ARP, DHCP, DHCPv6, NDP) - Flow-aware queue routing that tracks the originating TX queue for each flow and routes return packets to the corresponding RX queue - Test coverage with VHOST_USER_MQ environment variable to validate multiqueue functionality across all protocols (TCP, UDP, ICMP) and services (DHCP, NDP) Current behavior: - TX queue selection is controlled by the guest kernel's networking stack - RX packets are routed to queues based on their associated flows, with the queue assignment updated on each packet from TX to maintain affinity - Host-initiated flows (e.g., from socket-side connections) currently default to queue pair 0 The changes are transparent to single-queue operation - passt/pasta modes and single-queue vhost-user configurations continue to work unchanged, always using queue pair 0. v3: - Removed --max-qpairs configuration option - multiqueue support is now always enabled up to 16 queue pairs without requiring explicit configuration - Replaced "tap: Add queue pair parameter throughout the packet processing path" with "tap: Convert packet pools to per-queue-pair arrays for multiqueue" - simplified implementation by converting global pools to arrays rather than passing pool parameters throughout - Changed qpair parameter type from int to unsigned int throughout the codebase - Simplified test infrastructure - queues parameter is always set on netdev, mq=true added to virtio-net only when VHOST_USER_MQ > 1 - Updated QEMU usage hints to always show multiqueue-capable command line v2: - New patch: "tap: Remove pool parameter from tap4_handler() and tap6_handler()" to clean up unused parameters before adding queue pair parameter - Changed to one packet pool per queue pair instead of shared pools across all queue pairs - Split "multiqueue: Add queue-aware flow management..." into two patches: - "tap: Add queue pair parameter throughout the packet processing path" - "flow: Add queue pair tracking to flow management" - Updated test infrastructure patch with refined implementation Laurent Vivier (6): tap: Remove pool parameter from tap4_handler() and tap6_handler() vhost-user: Enable multiqueue test: Add multiqueue support to vhost-user test infrastructure vhost-user: Add queue pair parameter throughout the network stack tap: Convert packet pools to per-queue-pair arrays for multiqueue flow: Add queue pair tracking to flow management arp.c | 15 +++-- arp.h | 6 +- dhcp.c | 5 +- dhcp.h | 2 +- dhcpv6.c | 12 ++-- dhcpv6.h | 2 +- flow.c | 33 +++++++++ flow.h | 17 +++++ fwd.c | 18 ++--- fwd.h | 5 +- icmp.c | 25 ++++--- icmp.h | 4 +- ndp.c | 35 ++++++---- ndp.h | 7 +- netlink.c | 2 +- tap.c | 177 ++++++++++++++++++++++++++++--------------------- tap.h | 20 +++--- tcp.c | 47 +++++++------ tcp.h | 7 +- tcp_vu.c | 8 ++- test/lib/setup | 21 +++--- test/run | 23 +++++++ udp.c | 47 +++++++------ udp.h | 6 +- udp_flow.c | 8 ++- udp_flow.h | 2 +- udp_internal.h | 4 +- udp_vu.c | 4 +- vhost_user.c | 10 +-- virtio.h | 2 +- vu_common.c | 15 +++-- vu_common.h | 3 +- 32 files changed, 374 insertions(+), 218 deletions(-) -- 2.51.1

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[PATCH v2 3/3] pasta: Clean up waiting pasta child on failures
by David Gibson 11 Dec '25

11 Dec '25

When pasta is invoked with a command rather than an existing namespace to attach to, it spawns a child process to run a shell or other command. We create that process during conf(), since we need the namespace to exist for much of our setup. However, we don't want the specified command to run until the pasta network interface is ready for use. Therefore, pasta_spawn_cmd() executing in the child waits before exec()ing. main() signals the child to continue with SIGUSR1 shortly before entering the main forwarding loop. This has the downside that if we exit due to any kind of failure between conf() and the SIGUSR1, the child process will be around waiting indefinitely. The user must manually clean this up. Make this cleaner, by having the child use PR_SET_PDEATHSIG to have itself killed if the parent dies during this window. Technically speaking this is racy: if the parent dies before the child can call the prctl() it will be left zombie-like as before. However, as long as the parent completes pasta_wait_for_ns() before dying, I wasn't able to trigger the race. Since the consequences of this going wrong are merely a bit ugly, I think that's good enough. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- pasta.c | 11 +++++++++++ util.c | 1 + 2 files changed, 12 insertions(+) diff --git a/pasta.c b/pasta.c index 5c693de1..c307b8a8 100644 --- a/pasta.c +++ b/pasta.c @@ -40,6 +40,7 @@ #include <arpa/inet.h> #include <netinet/in.h> #include <net/ethernet.h> +#include <sys/prctl.h> #include <sys/syscall.h> #include <linux/magic.h> @@ -189,6 +190,10 @@ static int pasta_spawn_cmd(void *arg) size_t conf_hostname_len; sigset_t set; + /* If the parent dies with an error, so should we */ + if (prctl(PR_SET_PDEATHSIG, SIGKILL)) + die_perror("Couldn't set PR_SET_PDEATHSIG"); + /* We run in a detached PID and mount namespace: mount /proc over */ if (mount("", "/proc", "proc", 0, NULL)) warn_perror("Couldn't mount /proc"); @@ -215,6 +220,12 @@ static int pasta_spawn_cmd(void *arg) sigaddset(&set, SIGUSR1); sigwaitinfo(&set, NULL); + /* Once exec()ed this process is more valuable, and easier to see and + * clean up. Let us outlive our parent now. + */ + if (prctl(PR_SET_PDEATHSIG, 0)) + die_perror("Couldn't clear PR_SET_PDEATHSIG"); + execvp(a->exe, a->argv); die_perror("Failed to start command or shell"); diff --git a/util.c b/util.c index da12c962..27303950 100644 --- a/util.c +++ b/util.c @@ -35,6 +35,7 @@ #include "log.h" #include "pcap.h" #include "epoll_ctl.h" +#include "pasta.h" #ifdef HAS_GETRANDOM #include <sys/random.h> #endif -- 2.52.0

3 3

[PATCH 1/2] treewide: Introduce passt_exit() helper
by David Gibson 11 Dec '25

11 Dec '25

In d0006fa78 ("treewide: use _exit() over exit()"), we replaced use of the normal exit(3) with direct calls to _exit(2). That was because glibc exit(3) made some unexpected futex() calls, which hit our seccomp profile. We've since had some bugs due to missing the extra cleanup that exit(3) implemented, for which we've added explicit cleanup calls. Specifically, we have fflush() calls in some places to avoid leaving incomplete messages on stdout/stderr, and in other places fsync_pcap_and_log() to avoid leaving incomplete log or pcap files. It's easy to forget these when adding new error paths, so instead, implement our own passt_exit() wrapper to perform vital cleanup then call _exit(2). This also provides an obvious place to add any additional cleanups we discover we need in future. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- conf.c | 11 ++++------- log.h | 9 +++++++-- passt.c | 5 ++--- pasta.c | 10 ++++------ tap.c | 6 ++---- util.c | 24 ++++++++++++++++++------ util.h | 1 - vhost_user.c | 4 ++-- 8 files changed, 39 insertions(+), 31 deletions(-) diff --git a/conf.c b/conf.c index fdc19e81..24b44419 100644 --- a/conf.c +++ b/conf.c @@ -826,7 +826,7 @@ static void conf_ip6_local(struct ip6_ctx *ip6) * usage() - Print usage, exit with given status code * @name: Executable name * @f: Stream to print usage info to - * @status: Status code for _exit() + * @status: Status code for exit(2) */ static void usage(const char *name, FILE *f, int status) { @@ -997,8 +997,7 @@ static void usage(const char *name, FILE *f, int status) " SPEC is as described for TCP above\n" " default: none\n"); - (void)fflush(f); - _exit(status); + passt_exit(status); pasta_opts: @@ -1052,8 +1051,7 @@ pasta_opts: " --ns-mac-addr ADDR Set MAC address on tap interface\n" " --no-splice Disable inbound socket splicing\n"); - (void)fflush(f); - _exit(status); + passt_exit(status); } /** @@ -1621,8 +1619,7 @@ void conf(struct ctx *c, int argc, char **argv) FPRINTF(stdout, c->mode == MODE_PASTA ? "pasta " : "passt "); FPRINTF(stdout, VERSION_BLOB); - (void)fflush(stdout); - _exit(EXIT_SUCCESS); + passt_exit(EXIT_SUCCESS); case 15: ret = snprintf(c->ip4.ifname_out, sizeof(c->ip4.ifname_out), "%s", optarg); diff --git a/log.h b/log.h index c8473c0d..b7b20672 100644 --- a/log.h +++ b/log.h @@ -9,6 +9,11 @@ #include <stdbool.h> #include <syslog.h> +/* This would make more sense in util.h, but because we use it in die(), that + * would cause awkward circular reference problems. + */ +void passt_exit(int status) __attribute__((noreturn)); + #define LOGFILE_SIZE_DEFAULT (1024 * 1024UL) #define LOGFILE_CUT_RATIO 30 /* When full, cut ~30% size */ #define LOGFILE_SIZE_MIN (5UL * MAX(BUFSIZ, PAGE_SIZE)) @@ -32,13 +37,13 @@ void logmsg_perror(int pri, const char *format, ...) #define die(...) \ do { \ err(__VA_ARGS__); \ - _exit(EXIT_FAILURE); \ + passt_exit(EXIT_FAILURE); \ } while (0) #define die_perror(...) \ do { \ err_perror(__VA_ARGS__); \ - _exit(EXIT_FAILURE); \ + passt_exit(EXIT_FAILURE); \ } while (0) extern int log_file; diff --git a/passt.c b/passt.c index 5ed88d07..cf38822f 100644 --- a/passt.c +++ b/passt.c @@ -177,8 +177,7 @@ static void exit_handler(int signal) { (void)signal; - fsync_pcap_and_log(); - _exit(EXIT_SUCCESS); + passt_exit(EXIT_SUCCESS); } /** @@ -399,7 +398,7 @@ int main(int argc, char **argv) flow_init(); if ((!c.no_udp && udp_init(&c)) || (!c.no_tcp && tcp_init(&c))) - _exit(EXIT_FAILURE); + passt_exit(EXIT_FAILURE); proto_update_l2_buf(c.guest_mac); diff --git a/pasta.c b/pasta.c index 674b5542..5c693de1 100644 --- a/pasta.c +++ b/pasta.c @@ -70,15 +70,13 @@ void pasta_child_handler(int signal) if (pasta_child_pid && !waitid(P_PID, pasta_child_pid, &infop, WEXITED | WNOHANG)) { if (infop.si_pid == pasta_child_pid) { - fsync_pcap_and_log(); - if (infop.si_code == CLD_EXITED) - _exit(infop.si_status); + passt_exit(infop.si_status); /* If killed by a signal, si_status is the number. * Follow common shell convention of returning it + 128. */ - _exit(infop.si_status + 128); + passt_exit(infop.si_status + 128); /* Nothing to do, detached PID namespace going away */ } @@ -511,7 +509,7 @@ void pasta_netns_quit_inotify_handler(struct ctx *c, int inotify_fd) if (!strncmp(ev->name, c->netns_base, sizeof(c->netns_base))) { info("Namespace %s is gone, exiting", c->netns_base); - _exit(EXIT_SUCCESS); + passt_exit(EXIT_SUCCESS); } } } @@ -539,7 +537,7 @@ void pasta_netns_quit_timer_handler(struct ctx *c, union epoll_ref ref) return; info("Namespace %s is gone, exiting", c->netns_base); - _exit(EXIT_SUCCESS); + passt_exit(EXIT_SUCCESS); } close(fd); diff --git a/tap.c b/tap.c index e3ea61cb..9d1344b2 100644 --- a/tap.c +++ b/tap.c @@ -1149,10 +1149,8 @@ void tap_sock_reset(struct ctx *c) { info("Client connection closed%s", c->one_off ? ", exiting" : ""); - if (c->one_off) { - fsync_pcap_and_log(); - _exit(EXIT_SUCCESS); - } + if (c->one_off) + passt_exit(EXIT_SUCCESS); /* Close the connected socket, wait for a new connection */ epoll_del(c->epollfd, c->fd_tap); diff --git a/util.c b/util.c index bfeb6191..e266c396 100644 --- a/util.c +++ b/util.c @@ -555,7 +555,7 @@ void pidfile_write(int fd, pid_t pid) if (write(fd, pid_buf, n) < 0) { perror("PID file write"); - _exit(EXIT_FAILURE); + passt_exit(EXIT_FAILURE); } close(fd); @@ -592,12 +592,12 @@ int __daemon(int pidfile_fd, int devnull_fd) if (pid == -1) { perror("fork"); - _exit(EXIT_FAILURE); + passt_exit(EXIT_FAILURE); } if (pid) { pidfile_write(pidfile_fd, pid); - _exit(EXIT_SUCCESS); + passt_exit(EXIT_SUCCESS); } if (setsid() < 0 || @@ -605,7 +605,7 @@ int __daemon(int pidfile_fd, int devnull_fd) dup2(devnull_fd, STDOUT_FILENO) < 0 || dup2(devnull_fd, STDERR_FILENO) < 0 || close(devnull_fd)) - _exit(EXIT_FAILURE); + passt_exit(EXIT_FAILURE); return 0; } @@ -1225,17 +1225,29 @@ void abort_with_msg(const char *fmt, ...) } /** - * fsync_pcap_and_log() - Flush pcap and log files as needed + * passt_exit() - Perform vital cleanup and exit + * + * We don't use exit(3) because on some C library versions it can do unexpected + * things that hit our seccomp profile (e.g. futex() calls). This is a bespoke + * wrapper around _exit(2) performing just the cleanup that we need. * * #syscalls fsync */ -void fsync_pcap_and_log(void) +void passt_exit(int status) { + /* Make sure we don't leave the pcap file truncated */ if (pcap_fd != -1 && fsync(pcap_fd)) warn_perror("Failed to flush pcap file, it might be truncated"); + /* Make sure we don't leave an incomplete log */ if (log_file != -1) (void)fsync(log_file); + + /* Make sure we dont leave any messages incomplete */ + (void)fflush(stderr); + (void)fflush(stdout); + + _exit(status); } /** diff --git a/util.h b/util.h index f7a941fd..4cbb5da3 100644 --- a/util.h +++ b/util.h @@ -242,7 +242,6 @@ int read_all_buf(int fd, void *buf, size_t len); int read_remainder(int fd, const struct iovec *iov, size_t cnt, size_t skip); void close_open_files(int argc, char **argv); bool snprintf_check(char *str, size_t size, const char *format, ...); -void fsync_pcap_and_log(void); long clamped_scale(long x, long y, long lo, long hi, long f); /** diff --git a/vhost_user.c b/vhost_user.c index aa7c869d..f9a5646c 100644 --- a/vhost_user.c +++ b/vhost_user.c @@ -60,7 +60,7 @@ void vu_print_capabilities(void) info("{"); info(" \"type\": \"net\""); info("}"); - _exit(EXIT_SUCCESS); + passt_exit(EXIT_SUCCESS); } /** @@ -1202,7 +1202,7 @@ void vu_control_handler(struct vu_dev *vdev, int fd, uint32_t events) !vdev->context->migrate_target) { if (vdev->context->migrate_exit) { info("Migration complete, exiting"); - _exit(EXIT_SUCCESS); + passt_exit(EXIT_SUCCESS); } info("Migration complete"); -- 2.52.0

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[PATCH] tcp: Suppress new instance of cppcheck bug 14191
by David Gibson 11 Dec '25

11 Dec '25

From: Laurent Vivier <lvivier(a)redhat.com> ee9b2361d ("cppcheck: Suppress a buggy cppcheck warning") added a a suppression for a cppchec bug, since filed (and fixed) in upstream cppcheck as https://trac.cppcheck.net/ticket/14191. 9139e60fd ("tcp: Acknowledge everything if it looks like bulk traffic, not interactive") introduced a new point which triggers the same cppcheck bug. Add a suppression for the new instance. This is a revision of Laurent's earlier patch, updating the comments to make the connection between the two instances clear, and adding unmatchedSuppression so it doesn't cause a bogus warning with unaffected cppcheck versions. Signed-off-by: Laurent Vivier <lvivier(a)redhat.com> Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- tcp.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/tcp.c b/tcp.c index 7c721b4b..1711bcc7 100644 --- a/tcp.c +++ b/tcp.c @@ -1132,6 +1132,11 @@ int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn, return 0; } + /* This trips a cppcheck bug in some versions, including + * cppcheck 2.18.3. + * https://trac.cppcheck.net/ticket/14191 + */ + /* cppcheck-suppress [uninitvar,unmatchedSuppression] */ if ((unsigned)SNDBUF_GET(conn) > (long long)tinfo->tcpi_rtt * tinfo->tcpi_delivery_rate / 1000 / 1000 * @@ -1143,10 +1148,7 @@ int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn, /* Fall back to acknowledging everything we got */ conn->seq_ack_to_tap = conn->seq_from_tap; } else { - /* This trips a cppcheck bug in some versions, including - * cppcheck 2.18.3. - * https://sourceforge.net/p/cppcheck/discussion/general/thread/fecde59085/ - */ + /* cppcheck bug 14191 again, see above */ /* cppcheck-suppress [uninitvar,unmatchedSuppression] */ conn->seq_ack_to_tap = tinfo->tcpi_bytes_acked + conn->seq_init_from_tap; -- 2.52.0

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passt: new version 2025_12_10.d04c480 available
by Stefano Brivio 10 Dec '25

10 Dec '25

Subject: passt: new version 2025_12_10.d04c480 available The new version with tag 2025_12_10.d04c480 includes the following changes: d04c480 pif: Correctly set scope_id for guest-side link local addresses 696709d tcp: Correct timer expiry value in trace message https://passt.top/passt/log/?qt=range&q=2025_12_09.c3f1ba7..2025_12_10.d04c… Packages: - Alpine Linux: https://pkgs.alpinelinux.org/packages?name=passt - Arch Linux: https://www.archlinux.org/packages/extra/x86_64/passt/ https://archlinuxarm.org/packages/aarch64/passt https://archlinuxarm.org/packages/armv7h/passt - Chimera: https://pkgs.chimera-linux.org/packages?name=passt - Clear Linux: https://github.com/clearlinux-pkgs/passt/ - Copr (CentOS Stream, EPEL, Fedora, Mageia): https://copr.fedorainfracloud.org/coprs/sbrivio/passt/build/9896122/ permanent mirror: https://passt.top/builds/copr/0^20251210.gd04c480/ - Debian tracker: https://tracker.debian.org/pkg/passt - Fedora updates: https://bodhi.fedoraproject.org/updates/?packages=passt - Gentoo versions: https://packages.gentoo.org/packages/net-misc/passt - GNU Guix: https://packages.guix.gnu.org/packages/passt/ - Homebrew: https://formulae.brew.sh/formula/passt - NixOS: https://github.com/NixOS/nixpkgs/tree/nixos-unstable/pkgs/by-name/pa/passt - openSUSE: https://software.opensuse.org/package/passt - OpenMandriva: https://github.com/OpenMandrivaAssociation/passt/tree/master - PLD Linux: https://git.pld-linux.org/cgi-bin/gitweb.cgi?p=packages/passt.git - Solus: https://github.com/getsolus/packages/tree/main/packages/p/passt - Ubuntu tracker: https://launchpad.net/ubuntu/+source/passt - Void Linux: https://voidlinux.org/packages/?q=passt - Static builds: - Package for other RPM-based distributions, x86_64 only: https://passt.top/builds/latest/x86_64/passt-gd04c480-1.x86_64.rpm - x86_64 static binaries: https://passt.top/builds/latest/x86_64/ - Debian package, from x86_64 static build: https://passt.top/builds/latest/x86_64/passt_0d04c480-1_all.deb -- Stefano

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[PATCH 0/2] Bug 181 & bug 182
by David Gibson 10 Dec '25

10 Dec '25

These are fixes for two regressions in the latest release. David Gibson (2): tcp: Correct timer expiry value in trace message pif: Correctly set scope_id for guest-side link local addresses pif.c | 10 +++++++--- tcp.c | 10 +++++----- 2 files changed, 12 insertions(+), 8 deletions(-) -- 2.52.0

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[PATCH 2/2] pif: Correctly set scope_id for guest-side link local addresses
by David Gibson 10 Dec '25

10 Dec '25

pif_sockaddr() is supposed to generate a suitable socket address, either for the host, or for the guest, depending on the 'pif' parameter. When given a link-local address, this means it needs to generate a suitable scope_id to specify which link. It does this for the host, but not for the guest. I think this was done on the assumption that we won't ever generate guest side link local addresses when forwarding connections. That, however, is not the case, at least with the recent extensions to "local mode". Fix the problem by properly populating the scope_id field for guest addresses. Link: https://bugs.passt.top/show_bug.cgi?id=181 Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- pif.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/pif.c b/pif.c index 3d7a90e5..6ae970a0 100644 --- a/pif.c +++ b/pif.c @@ -50,10 +50,14 @@ void pif_sockaddr(const struct ctx *c, union sockaddr_inany *sa, sa->sa_family = AF_INET6; sa->sa6.sin6_addr = addr->a6; sa->sa6.sin6_port = htons(port); - if (pif == PIF_HOST && IN6_IS_ADDR_LINKLOCAL(&addr->a6)) - sa->sa6.sin6_scope_id = c->ifi6; - else + if (IN6_IS_ADDR_LINKLOCAL(&addr->a6)) { + if (pif == PIF_HOST) + sa->sa6.sin6_scope_id = c->ifi6; + else if (pif == PIF_SPLICE) + sa->sa6.sin6_scope_id = c->pasta_ifi; + } else { sa->sa6.sin6_scope_id = 0; + } sa->sa6.sin6_flowinfo = 0; } } -- 2.52.0

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[PATCH 1/2] tcp: Correct timer expiry value in trace message
by David Gibson 10 Dec '25

10 Dec '25

000601ba8 ("tcp: Adaptive interval based on RTT for socket-side acknowledgement checks") added (amongst other things) a new trace message showing the expiry time for the TCP timer in ms rather than s. Unfortunately there were some arithmetic errors in the message, meaning it will print incorrect numbers. Correct them Fixes: 000601ba86da ("tcp: Adaptive interval based on RTT for socket-side acknowledgement checks") Link: https://bugs.passt.top/show_bug.cgi?id=182 Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- tcp.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/tcp.c b/tcp.c index 8dabfd30..ce36bbd3 100644 --- a/tcp.c +++ b/tcp.c @@ -626,11 +626,11 @@ static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn) } if (conn->flags & ACK_TO_TAP_DUE) { - flow_trace(conn, "timer expires in %llu.%03llums", - (unsigned long)it.it_value.tv_sec * 1000 + - (unsigned long long)it.it_value.tv_nsec % - ((long)1000 * 1000), - (unsigned long long)it.it_value.tv_nsec / 1000); + flow_trace(conn, "timer expires in %llu.%02llums", + (unsigned long long)it.it_value.tv_sec * 1000 + + it.it_value.tv_nsec / 1000 / 1000, + (unsigned long long)it.it_value.tv_nsec + / 1000 / 10 % 100); } else { flow_dbg(conn, "timer expires in %llu.%03llus", (unsigned long long)it.it_value.tv_sec, -- 2.52.0

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[PATCH 0/2] Improved exit()/_exit() handling
by David Gibson 10 Dec '25

10 Dec '25

As discussed on IRC, while working on the forwarding extensions, I discovered that failures at certain points of initialisation (in particular tcp_init() or udp_init() can result in a zombie pasta child process. Here's a fix. David Gibson (2): treewide: Introduce passt_exit() helper pasta: Clean up waiting pasta child on failures conf.c | 11 ++++------- log.h | 9 +++++++-- passt.c | 6 +++--- pasta.c | 12 ++++++------ pasta.h | 1 + tap.c | 6 ++---- util.c | 29 +++++++++++++++++++++++------ util.h | 1 - vhost_user.c | 4 ++-- 9 files changed, 48 insertions(+), 31 deletions(-) -- 2.52.0

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