- dev - passt

[PATCH 0/4] RFC: Improvements to flow specific logging
by David Gibson 09 Jun '26

09 Jun '26

While working on podman bug 23739, I found some deficiences in how and when we report various socket errors related to specific flows. Here are some preliminary patches to improve that. I think patches 1..3 are pretty straightforward and safe. 4/4 I think is a good idea in principle - promoting the priority of a number of messages now that we have ratelimiting. However, plumbing 'now' all the places we need it resuls in a *lot* of churn, so we might want to postpone or split it up. Still, current drafted posted for consideration. David Gibson (4): flow: Regularise flow specific logging helpers flow: Include flow details with higher priority log messages flow: Safer errno handling in flowside_connect() callers flow, treewide: Promote priority of selected flow-linked messages flow.c | 107 +++++++------- flow.h | 72 +++++----- icmp.c | 27 ++-- icmp.h | 3 +- migrate.c | 27 ++-- migrate.h | 8 +- passt.c | 8 +- tcp.c | 381 ++++++++++++++++++++++++++++--------------------- tcp.h | 5 +- tcp_buf.c | 78 +++++----- tcp_buf.h | 8 +- tcp_conn.h | 8 +- tcp_internal.h | 27 ++-- tcp_splice.c | 59 +++++--- tcp_splice.h | 3 +- tcp_vu.c | 42 +++--- tcp_vu.h | 6 +- udp.c | 48 ++++--- udp_flow.c | 22 +-- 19 files changed, 535 insertions(+), 404 deletions(-) -- 2.54.0

1 3

[PATCH 1/4] flow: Regularise flow specific logging helpers
by David Gibson 09 Jun '26

09 Jun '26

flow.h has a collection of logging helpers that automatically include information about a specific flow. Which variants are present are a bit ad-hoc, based on what we happened to want use (e.g. there are no LOG_WARNING level versions, at present). There's also a rather awkward and only occasionally used flow_log_details_() helper to print additional log messages with more details of the flow (basically its addresses). It's particularly awkward to try to combine that with ratelimiting. Re-organise this to be based around a flow_log__() internal helper, which has bool parameters to include strerror() / perror information and/or the extra details. Add wrapper macros for all combinations of perror, ratelimiting and DEBUG/WARNING/ERR priorities. Be a little more consistent about parameter order between the various functions / macros / wrappers while we're at it. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- flow.c | 89 ++++++++++++++++++++++++++++------------------------------ flow.h | 70 +++++++++++++++++++++++---------------------- tcp.c | 4 +-- udp.c | 6 ++-- 4 files changed, 85 insertions(+), 84 deletions(-) diff --git a/flow.c b/flow.c index 565ed2b2..6cf3905a 100644 --- a/flow.c +++ b/flow.c @@ -270,17 +270,20 @@ int flowside_connect(const struct ctx *c, int s, return connect(s, &sa.sa, socklen_inany(&sa)); } -/** flow_log_ - Log flow-related message +/** flow_log__ - Log flow-related message, internal helper * @f: flow the message is related to - * @newline: Append newline at the end of the message, if missing * @pri: Log priority + * @perror: Append strerror(errno) output + * @details: Add lines with flow addresses + * @state: State to display details for (used during state changes) * @fmt: Format string * @...: printf-arguments */ -void flow_log_(const struct flow_common *f, bool newline, int pri, - const char *fmt, ...) +void flow_log__(const struct flow_common *f, int pri, bool perror, bool details, + enum flow_state state, const char *fmt, ...) { const char *type_or_state; + int errno_ = errno; char msg[BUFSIZ]; va_list args; @@ -294,45 +297,41 @@ void flow_log_(const struct flow_common *f, bool newline, int pri, else type_or_state = FLOW_TYPE(f); - logmsg(newline, false, pri, + logmsg(!perror, false, pri, "Flow %u (%s): %s", flow_idx(f), type_or_state, msg); -} -/** flow_log_details_() - Log the details of a flow - * @f: flow to log - * @pri: Log priority - * @state: State to log details according to - * - * Logs the details of the flow: endpoints, interfaces, type etc. - */ -void flow_log_details_(const struct flow_common *f, int pri, - enum flow_state state) -{ - char estr0[INANY_ADDRSTRLEN], fstr0[INANY_ADDRSTRLEN]; - char estr1[INANY_ADDRSTRLEN], fstr1[INANY_ADDRSTRLEN]; - const struct flowside *ini = &f->side[INISIDE]; - const struct flowside *tgt = &f->side[TGTSIDE]; - - if (state >= FLOW_STATE_TGT) - flow_log_(f, true, pri, - "%s [%s]:%hu -> [%s]:%hu => %s [%s]:%hu -> [%s]:%hu", - pif_name(f->pif[INISIDE]), - inany_ntop(&ini->eaddr, estr0, sizeof(estr0)), - ini->eport, - inany_ntop(&ini->oaddr, fstr0, sizeof(fstr0)), - ini->oport, - pif_name(f->pif[TGTSIDE]), - inany_ntop(&tgt->oaddr, fstr1, sizeof(fstr1)), - tgt->oport, - inany_ntop(&tgt->eaddr, estr1, sizeof(estr1)), - tgt->eport); - else if (state >= FLOW_STATE_INI) - flow_log_(f, true, pri, "%s [%s]:%hu -> [%s]:%hu => ?", - pif_name(f->pif[INISIDE]), - inany_ntop(&ini->eaddr, estr0, sizeof(estr0)), - ini->eport, - inany_ntop(&ini->oaddr, fstr0, sizeof(fstr0)), - ini->oport); + if (perror) + logmsg(true, true, pri, ": %s", strerror_(errno_)); + + if (details) { + char estr0[INANY_ADDRSTRLEN], fstr0[INANY_ADDRSTRLEN]; + char estr1[INANY_ADDRSTRLEN], fstr1[INANY_ADDRSTRLEN]; + const struct flowside *ini = &f->side[INISIDE]; + const struct flowside *tgt = &f->side[TGTSIDE]; + + if (state >= FLOW_STATE_TGT) { + flow_log__(f, pri, false, false, state, +"%s [%s]:%hu -> [%s]:%hu => %s [%s]:%hu -> [%s]:%hu", + pif_name(f->pif[INISIDE]), + inany_ntop(&ini->eaddr, estr0, sizeof(estr0)), + ini->eport, + inany_ntop(&ini->oaddr, fstr0, sizeof(fstr0)), + ini->oport, + pif_name(f->pif[TGTSIDE]), + inany_ntop(&tgt->oaddr, fstr1, sizeof(fstr1)), + tgt->oport, + inany_ntop(&tgt->eaddr, estr1, sizeof(estr1)), + tgt->eport); + } else if (state >= FLOW_STATE_INI) { + flow_log__(f, pri, false, false, state, + "%s [%s]:%hu -> [%s]:%hu => ?", + pif_name(f->pif[INISIDE]), + inany_ntop(&ini->eaddr, estr0, sizeof(estr0)), + ini->eport, + inany_ntop(&ini->oaddr, fstr0, sizeof(fstr0)), + ini->oport); + } + } } /** @@ -348,10 +347,9 @@ static void flow_set_state(struct flow_common *f, enum flow_state state) assert(oldstate < FLOW_NUM_STATES); f->state = state; - flow_log_(f, true, LOG_DEBUG, "%s -> %s", flow_state_str[oldstate], + flow_log__(f, LOG_DEBUG, false, true, MAX(state, oldstate), + "%s -> %s", flow_state_str[oldstate], FLOW_STATE(f)); - - flow_log_details_(f, LOG_DEBUG, MAX(state, oldstate)); } /** @@ -552,8 +550,7 @@ norule: /* This shouldn't happen, because if there's no rule for it we should * have no listening socket that would let us get here */ - flow_dbg(flow, "Missing forward rule"); - flow_log_details_(f, LOG_DEBUG, f->state); + flow_log(flow, LOG_DEBUG, false, true, "Missing forward rule"); nofwd: flow_err(flow, "No rules to forward %s %s [%s]:%hu -> [%s]:%hu", diff --git a/flow.h b/flow.h index 6c6a9260..d168a35a 100644 --- a/flow.h +++ b/flow.h @@ -280,42 +280,46 @@ int flow_migrate_source(struct ctx *c, const struct migrate_stage *stage, int flow_migrate_target(struct ctx *c, const struct migrate_stage *stage, int fd); -void flow_log_(const struct flow_common *f, bool newline, int pri, - const char *fmt, ...) - __attribute__((format(printf, 4, 5))); - -#define flow_log(f_, pri, ...) flow_log_(&(f_)->f, true, (pri), __VA_ARGS__) -#define flow_dbg(f, ...) flow_log((f), LOG_DEBUG, __VA_ARGS__) -#define flow_err(f, ...) flow_log((f), LOG_ERR, __VA_ARGS__) - -#define flow_trace(f, ...) \ +void flow_log__(const struct flow_common *f, int pri, bool perror, bool details, + enum flow_state state, const char *fmt, ...); + +#define flow_log_(f_, pri_, perror_, details_, ...) \ + flow_log__((f_), (pri_), (perror_), (details_), (f_)->state, \ + __VA_ARGS__) + +#define flow_log(flow_, pri_, perror_, details_, ...) \ + flow_log_(&(flow_)->f, (pri_), (perror_), (details_), __VA_ARGS__) + +#define flow_dbg(flow_, ...) \ + flow_log((flow_), LOG_DEBUG, false, false, __VA_ARGS__) +#define flow_warn(flow_, ...) \ + flow_log((flow_), LOG_WARNING, false, false, __VA_ARGS__) +#define flow_err(flow_, ...) \ + flow_log((flow_), LOG_ERR, false, false, __VA_ARGS__) +#define flow_trace(flow_, ...) \ do { \ if (log_trace) \ - flow_dbg((f), __VA_ARGS__); \ - } while (0) - -#define flow_log_perror_(f, pri, ...) \ - do { \ - int errno_ = errno; \ - flow_log_((f), false, (pri), __VA_ARGS__); \ - logmsg(true, true, (pri), ": %s", strerror_(errno_)); \ + flow_dbg((flow_), __VA_ARGS__); \ } while (0) -#define flow_dbg_perror(f_, ...) flow_log_perror_(&(f_)->f, LOG_DEBUG, __VA_ARGS__) -#define flow_perror(f_, ...) flow_log_perror_(&(f_)->f, LOG_ERR, __VA_ARGS__) - -void flow_log_details_(const struct flow_common *f, int pri, - enum flow_state state); -#define flow_log_details(f_, pri) \ - flow_log_details_(&((f_)->f), (pri), (f_)->f.state) -#define flow_dbg_details(f_) flow_log_details((f_), LOG_DEBUG) -#define flow_err_details(f_) flow_log_details((f_), LOG_ERR) - -#define flow_dbg_ratelimit(f, now, ...) \ - logmsg_ratelimit(flow_dbg, debug, now, f, __VA_ARGS__) -#define flow_err_ratelimit(f, now, ...) \ - logmsg_ratelimit(flow_err, err, now, f, __VA_ARGS__) -#define flow_perror_ratelimit(f, now, ...) \ - logmsg_ratelimit(flow_perror, err, now, f, __VA_ARGS__) +#define flow_dbg_perror(flow_, ...) \ + flow_log((flow_), LOG_DEBUG, true, false, __VA_ARGS__) +#define flow_warn_perror(flow_, ...) \ + flow_log((flow_), LOG_WARNING, true, false, __VA_ARGS__) +#define flow_perror(flow_, ...) \ + flow_log((flow_), LOG_ERR, true, false, __VA_ARGS__) + +#define flow_dbg_ratelimit(flow_, now_, ...) \ + logmsg_ratelimit(flow_dbg, debug, (now_), (flow_), __VA_ARGS__) +#define flow_dbg_perror_ratelimit(flow_, now_, ...) \ + logmsg_ratelimit(flow_dbg_perror, debug, (now_), (flow_), __VA_ARGS__) +#define flow_warn_ratelimit(flow_, now_, ...) \ + logmsg_ratelimit(flow_warn, warn, (now_), (flow_), __VA_ARGS__) +#define flow_warn_perror_ratelimit(flow_, now_, ...) \ + logmsg_ratelimit(flow_warn_perror, warn, (now_), (flow_), __VA_ARGS__) +#define flow_err_ratelimit(flow_, now_, ...) \ + logmsg_ratelimit(flow_err, err, (now_), (flow_), __VA_ARGS__) +#define flow_perror_ratelimit(flow_, now_, ...) \ + logmsg_ratelimit(flow_perror, err, (now_), (flow_), __VA_ARGS__) #endif /* FLOW_H */ diff --git a/tcp.c b/tcp.c index c4000754..6fba865f 100644 --- a/tcp.c +++ b/tcp.c @@ -1404,8 +1404,8 @@ void tcp_linger0_(const struct flow_common *f, int s) */ if (setsockopt(s, SOL_SOCKET, SO_LINGER, &linger0, sizeof(linger0)) < 0) { - flow_log_perror_(f, LOG_DEBUG, - "SO_LINGER failed, may not send RST to peer"); + flow_log_(f, LOG_DEBUG, true, false, + "SO_LINGER failed, may not send RST to peer"); } } diff --git a/udp.c b/udp.c index c28d6ee2..f29ca3da 100644 --- a/udp.c +++ b/udp.c @@ -943,7 +943,8 @@ void udp_sock_handler(const struct ctx *c, union epoll_ref ref, if (events & EPOLLERR) { if (udp_sock_errs(c, ref.fd, ref.flowside, PIF_NONE, 0) < 0) { - flow_err(uflow, "Unrecoverable error on flow socket"); + flow_log(uflow, LOG_ERR, false, true, + "Unrecoverable error on flow socket"); goto fail; } } @@ -974,7 +975,7 @@ void udp_sock_handler(const struct ctx *c, union epoll_ref ref, udp_buf_sock_to_tap(c, s, n, tosidx); } } else { - flow_err(uflow, + flow_log(uflow, LOG_ERR, false, true, "No support for forwarding UDP from %s to %s", pif_name(pif_at_sidx(ref.flowside)), pif_name(topif)); @@ -984,7 +985,6 @@ void udp_sock_handler(const struct ctx *c, union epoll_ref ref, return; fail: - flow_err_details(uflow); udp_flow_close(c, uflow); } -- 2.54.0

1 0

[PATCH v2] util, passt: Close daemon-lifetime fds on exit to avoid Coverity warning
by Jon Maloy 09 Jun '26

09 Jun '26

conf_open_files() opens three file descriptors (fd_tap_listen, fd_repair_listen, fd_control_listen) that are held for the entire daemon lifetime. Because no close() call exists for them anywhere, Coverity flags each as INCOMPLETE_DEALLOCATOR. This is clearly a false positive, but we still want to get rid of this warning. We now register the execution context in global area so that passt_exit() can use it to close these descriptors before calling _exit(). All exit paths (signal handler, die(), die_perror()) funnel through passt_exit(), so this covers all cases. Signed-off-by: Jon Maloy <jmaloy(a)redhat.com> --- v2: - Made struct ctx global from the beginning, on suggestion from David Gibson. - Drop pidfile_fd from passt_exit() cleanup, since it can be closed directly after use. Signed-off-by: Jon Maloy <jmaloy(a)redhat.com> --- passt.c | 77 +++++++++++++++++++++++++++++++-------------------------- passt.h | 2 ++ util.c | 7 ++++++ 3 files changed, 51 insertions(+), 35 deletions(-) diff --git a/passt.c b/passt.c index b3f806b9..e75b80b1 100644 --- a/passt.c +++ b/passt.c @@ -62,6 +62,13 @@ char pkt_buf[PKT_BUF_BYTES] __attribute__ ((aligned(PAGE_SIZE))); +struct ctx passt_ctx = { + .pidfile_fd = -1, + .fd_tap = -1, + .pasta_netns_fd = -1, + .device_state_fd = -1, +}; + char *epoll_type_str[] = { [EPOLL_TYPE_TCP] = "connected TCP socket", [EPOLL_TYPE_TCP_SPLICE] = "connected spliced TCP socket", @@ -322,9 +329,9 @@ static void passt_worker(void *opaque, int nfds, struct epoll_event *events) */ int main(int argc, char **argv) { + struct ctx *c = &passt_ctx; struct epoll_event events[NUM_EPOLL_EVENTS]; int nfds, devnull_fd = -1; - struct ctx c = { 0 }; struct rlimit limit; struct timespec now; struct sigaction sa; @@ -336,18 +343,15 @@ int main(int argc, char **argv) isolate_initial(argc, argv); - c.pasta_netns_fd = c.fd_tap = c.pidfile_fd = -1; - c.device_state_fd = -1; - sigemptyset(&sa.sa_mask); sa.sa_flags = 0; sa.sa_handler = exit_handler; sigaction(SIGTERM, &sa, NULL); sigaction(SIGQUIT, &sa, NULL); - c.mode = conf_mode(argc, argv); + c->mode = conf_mode(argc, argv); - if (c.mode == MODE_PASTA) { + if (c->mode == MODE_PASTA) { sa.sa_handler = pasta_child_handler; if (sigaction(SIGCHLD, &sa, NULL)) die_perror("Couldn't install signal handlers"); @@ -358,67 +362,70 @@ int main(int argc, char **argv) madvise(pkt_buf, sizeof(pkt_buf), MADV_HUGEPAGE); - c.epollfd = epoll_create1(EPOLL_CLOEXEC); - if (c.epollfd == -1) + c->epollfd = epoll_create1(EPOLL_CLOEXEC); + if (c->epollfd == -1) die_perror("Failed to create epoll file descriptor"); - flow_epollid_register(EPOLLFD_ID_DEFAULT, c.epollfd); + flow_epollid_register(EPOLLFD_ID_DEFAULT, c->epollfd); if (getrlimit(RLIMIT_NOFILE, &limit)) die_perror("Failed to get maximum value of open files limit"); - c.nofile = limit.rlim_cur = limit.rlim_max; + c->nofile = limit.rlim_cur = limit.rlim_max; if (setrlimit(RLIMIT_NOFILE, &limit)) die_perror("Failed to set current limit for open files"); - sock_probe_features(&c); + sock_probe_features(c); - conf(&c, argc, argv); - trace_init(c.trace); + conf(c, argc, argv); + trace_init(c->trace); - pasta_netns_quit_init(&c); + pasta_netns_quit_init(c); - tap_backend_init(&c); + tap_backend_init(c); - random_init(&c); + random_init(c); if (clock_gettime(CLOCK_MONOTONIC, &now)) die_perror("Failed to get CLOCK_MONOTONIC time"); flow_init(); - fwd_scan_ports_init(&c); + fwd_scan_ports_init(c); - if ((!c.no_udp && udp_init(&c)) || (!c.no_tcp && tcp_init(&c))) + if ((!c->no_udp && udp_init(c)) || (!c->no_tcp && tcp_init(c))) passt_exit(EXIT_FAILURE); - if (fwd_listen_init(&c)) + if (fwd_listen_init(c)) passt_exit(EXIT_FAILURE); - proto_update_l2_buf(c.guest_mac); + proto_update_l2_buf(c->guest_mac); - if (c.ifi4 && !c.no_dhcp) + if (c->ifi4 && !c->no_dhcp) dhcp_init(); - if (c.ifi6 && !c.no_dhcpv6) - dhcpv6_init(&c); + if (c->ifi6 && !c->no_dhcpv6) + dhcpv6_init(c); - pcap_init(&c); + pcap_init(c); - fwd_neigh_table_init(&c); - nl_neigh_notify_init(&c); + fwd_neigh_table_init(c); + nl_neigh_notify_init(c); - if (!c.foreground) { + if (!c->foreground) { if ((devnull_fd = open("/dev/null", O_RDWR | O_CLOEXEC)) < 0) die_perror("Failed to open /dev/null"); } - if (isolate_prefork(&c)) + if (isolate_prefork(c)) die("Failed to sandbox process, exiting"); - if (!c.foreground) { - __daemon(c.pidfile_fd, devnull_fd); + if (!c->foreground) { + __daemon(c->pidfile_fd, devnull_fd); + close(c->pidfile_fd); + c->pidfile_fd = -1; log_stderr = false; } else { - pidfile_write(c.pidfile_fd, getpid()); + pidfile_write(c->pidfile_fd, getpid()); + c->pidfile_fd = -1; } if (pasta_child_pid) { @@ -426,19 +433,19 @@ int main(int argc, char **argv) log_stderr = false; } - isolate_postfork(&c); + isolate_postfork(c); - timer_init(&c, &now); + timer_init(c, &now); loop: /* NOLINTBEGIN(bugprone-branch-clone): intervals can be the same */ /* cppcheck-suppress [duplicateValueTernary, unmatchedSuppression] */ - nfds = epoll_wait(c.epollfd, events, NUM_EPOLL_EVENTS, TIMER_INTERVAL); + nfds = epoll_wait(c->epollfd, events, NUM_EPOLL_EVENTS, TIMER_INTERVAL); /* NOLINTEND(bugprone-branch-clone) */ if (nfds == -1 && errno != EINTR) die_perror("epoll_wait() failed in main loop"); - passt_worker(&c, nfds, events); + passt_worker(c, nfds, events); goto loop; } diff --git a/passt.h b/passt.h index 1726965d..e1905f4c 100644 --- a/passt.h +++ b/passt.h @@ -307,6 +307,8 @@ struct ctx { bool migrate_exit; }; +extern struct ctx passt_ctx; + void proto_update_l2_buf(const unsigned char *eth_d); #endif /* PASST_H */ diff --git a/util.c b/util.c index b64c29ed..ef6ba80e 100644 --- a/util.c +++ b/util.c @@ -1108,6 +1108,13 @@ void abort_with_msg(const char *fmt, ...) */ void passt_exit(int status) { + if (passt_ctx.fd_tap_listen >= 0) + close(passt_ctx.fd_tap_listen); + if (passt_ctx.fd_repair_listen >= 0) + close(passt_ctx.fd_repair_listen); + if (passt_ctx.fd_control_listen >= 0) + close(passt_ctx.fd_control_listen); + /* 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 1

[PATCH 0/8] splice() forwarding cleanups
by David Gibson 05 Jun '26

05 Jun '26

As we discussed on an earlier call, while fixing bug 202 I noticed a number of warts in the surrounding splice() forwarding code. Most are just things that are longer or harder to follow than they need to be, but in some cases there may be real (if unlikely to trigger) bugs. Here's a collection of fixes. David Gibson (8): tcp_splice: Remove never-invoked SO_RCVLOWAT logic tcp_splice: Simplify EPOLLRDHUP / eof / FIN handling tcp_splice: Improve EOF exit condition for the loop tcp_splice: Remove goto from forwarding loop tcp_splice: Simplify shutdown(2) handling tcp_splice: Simplify / correct OUT_WAIT flag handling tcp_splice: Remove questionable "optimisation" of pending bytes tracking tcp_splice: Exit forwarding earlier when stalled read side tcp_splice.c | 100 ++++++++++++++++----------------------------------- 1 file changed, 31 insertions(+), 69 deletions(-) -- 2.54.0

2 20

[PATCH] passt, tcp: Inline CALL_PROTO_HANDLER() and merge tcp_timer()
by Laurent Vivier 05 Jun '26

05 Jun '26

Since 260075bde769 ("tcp, udp, fwd: Run all port scanning from a single timer"), CALL_PROTO_HANDLER() has only one user (tcp), so inline it at the call site and remove the macro. Merge tcp_timer() into tcp_defer_handler(), moving the timer interval check there, matching the pattern used by flow_defer_handler() and fwd_scan_ports_timer(). The weak declaration and null check for tcp_defer_handler are also dropped as the function is always defined. Signed-off-by: Laurent Vivier <lvivier(a)redhat.com> --- passt.c | 23 ++--------------------- tcp.c | 22 ++++++++++------------ tcp.h | 3 +-- 3 files changed, 13 insertions(+), 35 deletions(-) diff --git a/passt.c b/passt.c index b6fc12d4ed81..b3f806b9a15e 100644 --- a/passt.c +++ b/passt.c @@ -101,27 +101,8 @@ struct passt_stats { */ static void post_handler(struct ctx *c, const struct timespec *now) { -#define CALL_PROTO_HANDLER(lc, uc) \ - do { \ - extern void \ - lc ## _defer_handler (struct ctx *c) \ - __attribute__ ((weak)); \ - \ - if (!c->no_ ## lc) { \ - if (lc ## _defer_handler) \ - lc ## _defer_handler(c); \ - \ - if (timespec_diff_ms((now), &c->lc.timer_run) \ - >= uc ## _TIMER_INTERVAL) { \ - lc ## _timer(c, now); \ - c->lc.timer_run = *now; \ - } \ - } \ - } while (0) - - /* NOLINTNEXTLINE(bugprone-branch-clone): intervals can be the same */ - CALL_PROTO_HANDLER(tcp, TCP); -#undef CALL_PROTO_HANDLER + if (!c->no_tcp) + tcp_defer_handler(c, now); flow_defer_handler(c, now); fwd_scan_ports_timer(c, now); diff --git a/tcp.c b/tcp.c index 0fb8da05cb65..c400075440c9 100644 --- a/tcp.c +++ b/tcp.c @@ -895,16 +895,6 @@ bool tcp_flow_defer(const struct tcp_tap_conn *conn) return true; } -/** - * tcp_defer_handler() - Handler for TCP deferred tasks - * @c: Execution context - */ -/* cppcheck-suppress [constParameterPointer, unmatchedSuppression] */ -void tcp_defer_handler(struct ctx *c) -{ - tcp_payload_flush(c); -} - /** * tcp_fill_header() - Fill the TCP header fields for a given TCP segment. * @@ -3005,12 +2995,20 @@ static void tcp_inactivity(struct ctx *c, const struct timespec *now) } /** - * tcp_timer() - Periodic tasks: port detection, closed connections, pool refill + * tcp_defer_handler() - Handler for TCP deferred tasks * @c: Execution context * @now: Current timestamp */ -void tcp_timer(struct ctx *c, const struct timespec *now) +/* cppcheck-suppress [constParameterPointer, unmatchedSuppression] */ +void tcp_defer_handler(struct ctx *c, const struct timespec *now) { + tcp_payload_flush(c); + + if (timespec_diff_ms(now, &c->tcp.timer_run) < TCP_TIMER_INTERVAL) + return; + + c->tcp.timer_run = *now; + tcp_sock_refill_init(c); if (c->mode == MODE_PASTA) tcp_splice_refill(c); diff --git a/tcp.h b/tcp.h index 8a0eb930b54b..3262a807e5d4 100644 --- a/tcp.h +++ b/tcp.h @@ -29,8 +29,7 @@ int tcp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af, int tcp_listen(const struct ctx *c, uint8_t pif, unsigned rule, const union inany_addr *addr, const char *ifname, in_port_t port); int tcp_init(struct ctx *c); -void tcp_timer(struct ctx *c, const struct timespec *now); -void tcp_defer_handler(struct ctx *c); +void tcp_defer_handler(struct ctx *c, const struct timespec *now); void tcp_update_l2_buf(const unsigned char *eth_d); -- 2.54.0

3 2

[PATCH 0/3] [PATCH 0/3] dhcpv6: Add --dhcpv6-opt for custom DHCPv6 options
by Anshu Kumari 05 Jun '26

05 Jun '26

This series adds a --dhcpv6-opt CODE,VALUE command-line option to inject custom options into DHCPv6 replies, complementing the existing --dhcp-opt support for DHCPv4. The primary use case is UEFI HTTP Boot, which requires Vendor Class (option 16) with the correct enterprise-number + length-prefixed wire encoding per RFC 8415 Section 21.16, and Boot File URL (option 59). Value formats are determined automatically from the option code via a type table. Supported types include plain strings, IPv6 addresses (single and list), 8/16/32-bit integers, vendor class (ENTERPRISE:DATA), and length-prefixed string lists. Patch 1 adds the CLI flag, storage, and basic man page entry. Patch 2 adds the type table and binary parser for all supported types. Patch 3 injects the parsed options into DHCPv6 reply packets. Anshu Kumari (3): conf: Add --dhcpv6-opt command-line option dhcpv6: Add option type table and value parser dhcpv6: Inject custom options into DHCPv6 replies conf.c | 26 ++++- dhcpv6.c | 295 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ dhcpv6.h | 1 + passt.1 | 30 ++++++ passt.h | 16 +++ 5 files changed, 367 insertions(+), 1 deletion(-) -- 2.54.0

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Startup fd to avoid busywaits
by Lisanna Dettwyler 03 Jun '26

03 Jun '26

Hello! I would like to propose a patch that allows the invoker to pass a "ready fd" on startup that gets written to once the setup has been completed, similar to slirp4netns's `--ready-fd` flag. Currently we have to poll the interface in a loop to wait for setup to be completed, and it would be much better if we could instead block on fd activity. Just wanted to check if such a contribution would be welcome before putting in the work of authoring it, or if there's already a better way to wait for the interface to come up. This is our current implementation: https://github.com/NixOS/nix/pull/15919/changes#diff-2a9176262efad1ef345d88… Thanks, Lisanna

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[PATCH] udp: Provide dummy iov in udp_peek_addr() to avoid Coverity warning
by Jon Maloy 02 Jun '26

02 Jun '26

udp_peek_addr() initialises struct msghdr without setting msg_iov, leaving it implicitly NULL. Coverity flags this as FORWARD_NULL, believing recvmsg() will dereference the NULL pointer. In practice, msg_iovlen being zero means the kernel never touches msg_iov, so the warning is a false positive. We now provide a one-byte dummy iov to make msg_iov non-NULL, hence suppressing this warning without changing the function's behaviour. Signed-off-by: Jon Maloy <jmaloy(a)redhat.com> --- udp.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/udp.c b/udp.c index c28d6ee2..f648cb8b 100644 --- a/udp.c +++ b/udp.c @@ -734,9 +734,16 @@ static int udp_peek_addr(int s, union sockaddr_inany *src, { char sastr[SOCKADDR_STRLEN], dstr[INANY_ADDRSTRLEN]; char cmsg[PKTINFO_SPACE]; + char dummy; + struct iovec iov = { + .iov_base = &dummy, + .iov_len = sizeof(dummy), + }; struct msghdr msg = { .msg_name = src, .msg_namelen = sizeof(*src), + .msg_iov = &iov, + .msg_iovlen = 1, .msg_control = cmsg, .msg_controllen = sizeof(cmsg), }; -- 2.52.0

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[PATCH] util, passt: Close daemon-lifetime fds on exit to avoid Coverity warning
by Jon Maloy 02 Jun '26

02 Jun '26

conf_open_files() opens four file descriptors (fd_tap_listen, fd_repair_listen, pidfile_fd, fd_control_listen) that are held for the entire daemon lifetime. Because no close() call exists for them anywhere, Coverity flags each as INCOMPLETE_DEALLOCATOR. This is clearly a false positive, but we still want to get rid of this warning. We now register the execution context so that passt_exit() can use to close these descriptors before calling _exit(). All exit paths (signal handler, die(), die_perror()) funnel through passt_exit(), so this covers all cases. Signed-off-by: Jon Maloy <jmaloy(a)redhat.com> --- log.h | 2 ++ passt.c | 1 + util.c | 22 ++++++++++++++++++++++ 3 files changed, 25 insertions(+) diff --git a/log.h b/log.h index 69cfb507..079f429c 100644 --- a/log.h +++ b/log.h @@ -63,7 +63,9 @@ extern bool debug_flag; /* This would make more sense in util.h, but because we use it in die(), that * would cause awkward circular reference problems. */ +struct ctx; void passt_exit(int status) __attribute__((noreturn)); +void passt_exit_set_ctx(struct ctx *c); #define LOGFILE_SIZE_DEFAULT (1024 * 1024UL) #define LOGFILE_CUT_RATIO 30 /* When full, cut ~30% size */ diff --git a/passt.c b/passt.c index b6fc12d4..ec6aa57a 100644 --- a/passt.c +++ b/passt.c @@ -392,6 +392,7 @@ int main(int argc, char **argv) sock_probe_features(&c); conf(&c, argc, argv); + passt_exit_set_ctx(&c); trace_init(c.trace); pasta_netns_quit_init(&c); diff --git a/util.c b/util.c index b64c29ed..f15b1f9a 100644 --- a/util.c +++ b/util.c @@ -1097,6 +1097,17 @@ void abort_with_msg(const char *fmt, ...) abort(); } +static struct ctx *exit_cleanup_ctx; + +/** + * passt_exit_set_ctx() - Register context for cleanup on exit + * @c: Execution context + */ +void passt_exit_set_ctx(struct ctx *c) +{ + exit_cleanup_ctx = c; +} + /** * passt_exit() - Perform vital cleanup and exit * @@ -1108,6 +1119,17 @@ void abort_with_msg(const char *fmt, ...) */ void passt_exit(int status) { + if (exit_cleanup_ctx) { + if (exit_cleanup_ctx->fd_tap_listen >= 0) + close(exit_cleanup_ctx->fd_tap_listen); + if (exit_cleanup_ctx->fd_repair_listen >= 0) + close(exit_cleanup_ctx->fd_repair_listen); + if (exit_cleanup_ctx->pidfile_fd >= 0) + close(exit_cleanup_ctx->pidfile_fd); + if (exit_cleanup_ctx->fd_control_listen >= 0) + close(exit_cleanup_ctx->fd_control_listen); + } + /* 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

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[PATCH v2 0/6] Add --dhcp-boot and --dhcp-opt options
by Anshu Kumari 02 Jun '26

02 Jun '26

This series adds support for custom DHCP options in passt, enabling network boot (PXE/UEFI HTTP Boot) and arbitrary DHCP option injection. Two new command-line flags are introduced: --dhcp-boot URL Sets the boot file URL (DHCP option 67 and the legacy boot file field) --dhcp-opt CODE,VALUE Sets any DHCP option by numeric code, with type-aware parsing per RFC 2132 The DHCP reply path is extended with option overload support (RFC 2132 option 52), allowing options to overflow into the file and sname fields when the standard options area is full. Anshu Kumari (6): conf: Add --dhcp-opt command-line option conf: Add --dhcp-boot command-line option dhcp: Add option type table and value parser dhcp: Refactor fill_one() to operate on a generic buffer dhcp: Add option overload doc: Add --dhcp-boot and --dhcp-opt to man page conf.c | 64 +++++++++++++- dhcp.c | 253 +++++++++++++++++++++++++++++++++++++++++++++++++++----- dhcp.h | 17 ++++ passt.1 | 41 +++++++++ passt.h | 16 ++++ 5 files changed, 370 insertions(+), 21 deletions(-) -- 2.54.0

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