- dev - passt

[PATCH v4 01/14] inany: Extend inany_ntop() to treat NULL as a fully unspecified address
by David Gibson 15 Jan '26

15 Jan '26

In a number of places we're using a convention that a NULL inany represents a dual-stack unspecified address, that is one which includes both 0.0.0.0 and ::. Extend inany_ntop() to handle that convention, representing it as "*". Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> Reviewed-by: Laurent Vivier <lvivier(a)redhat.com> --- inany.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/inany.c b/inany.c index 7680439d..87a4d8b6 100644 --- a/inany.c +++ b/inany.c @@ -22,7 +22,7 @@ const union inany_addr inany_loopback4 = INANY_INIT4(IN4ADDR_LOOPBACK_INIT); const union inany_addr inany_any4 = INANY_INIT4(IN4ADDR_ANY_INIT); /** inany_ntop - Convert an IPv[46] address to text format - * @src: IPv[46] address + * @src: IPv[46] address (NULL for unspecified) * @dst: output buffer, minimum INANY_ADDRSTRLEN bytes * @size: size of buffer at @dst * @@ -30,9 +30,12 @@ const union inany_addr inany_any4 = INANY_INIT4(IN4ADDR_ANY_INIT); */ const char *inany_ntop(const union inany_addr *src, char *dst, socklen_t size) { - const struct in_addr *v4 = inany_v4(src); + const struct in_addr *v4; + + if (!src) + return strncpy(dst, "*", size); - if (v4) + if ((v4 = inany_v4(src))) return inet_ntop(AF_INET, v4, dst, size); return inet_ntop(AF_INET6, &src->a6, dst, size); -- 2.52.0

1 0

[PATCH] conf, pasta: Add --no-tap option
by Yumei Huang 14 Jan '26

14 Jan '26

This patch introduces a mode where we only forward loopback connections and traffic between two namespaces (via the loopback interface, 'lo'), without a tap device. With this, podman can support forwarding ::1 in custom networks when using rootlesskit for forwarding ports. In --no-tap mode, --host-lo-to-ns-lo, --no-icmp and --no-ra is automatically enabled. Options requiring a tap device (--ns-ifname, --ns-mac-addr, --config-net, --outbound-if4/6) are rejected. Link: https://bugs.passt.top/show_bug.cgi?id=149 Signed-off-by: Yumei Huang <yuhuang(a)redhat.com> --- conf.c | 56 +++++++++++++++++++++++++++++++++++++++++--------------- fwd.c | 3 +++ passt.1 | 5 +++++ passt.h | 2 ++ pasta.c | 3 +++ tap.c | 11 +++++++---- 6 files changed, 61 insertions(+), 19 deletions(-) diff --git a/conf.c b/conf.c index 84ae12b..353d0a5 100644 --- a/conf.c +++ b/conf.c @@ -1049,7 +1049,8 @@ pasta_opts: " --no-copy-addrs DEPRECATED:\n" " Don't copy all addresses to namespace\n" " --ns-mac-addr ADDR Set MAC address on tap interface\n" - " --no-splice Disable inbound socket splicing\n"); + " --no-splice Disable inbound socket splicing\n" + " --no-tap Don't create tap device\n"); passt_exit(status); } @@ -1451,6 +1452,7 @@ void conf(struct ctx *c, int argc, char **argv) {"no-ndp", no_argument, &c->no_ndp, 1 }, {"no-ra", no_argument, &c->no_ra, 1 }, {"no-splice", no_argument, &c->no_splice, 1 }, + {"no-tap", no_argument, &c->no_tap, 1 }, {"freebind", no_argument, &c->freebind, 1 }, {"no-map-gw", no_argument, &no_map_gw, 1 }, {"ipv4-only", no_argument, NULL, '4' }, @@ -1947,8 +1949,11 @@ void conf(struct ctx *c, int argc, char **argv) } } while (name != -1); - if (c->mode != MODE_PASTA) + if (c->mode != MODE_PASTA) { c->no_splice = 1; + if (c->no_tap) + die("--no-tap is for pasta mode only"); + } if (c->mode == MODE_PASTA && !c->pasta_conf_ns) { if (copy_routes_opt) @@ -1957,6 +1962,25 @@ void conf(struct ctx *c, int argc, char **argv) die("--no-copy-addrs needs --config-net"); } + if (c->mode == MODE_PASTA && c->no_tap) { + if (c->no_splice) + die("--no-tap is incompatible with --no-splice"); + if (*c->ip4.ifname_out || *c->ip6.ifname_out) + die("--no-tap is incompatible with --outbound-if4/6"); + if (*c->pasta_ifn) + die("--no-tap is incompatible with --ns-ifname"); + if (*c->guest_mac) + die("--no-tap is incompatible with --ns-mac-addr"); + if (c->pasta_conf_ns) + die("--no-tap is incompatible with --config-net"); + + c->host_lo_to_ns_lo = 1; + c->no_icmp = 1; + c->no_ra = 1; + c->no_dns = 1; + c->no_dns_search = 1; + } + if (!ifi4 && *c->ip4.ifname_out) ifi4 = if_nametoindex(c->ip4.ifname_out); @@ -1980,9 +2004,9 @@ void conf(struct ctx *c, int argc, char **argv) log_conf_parsed = true; /* Stop printing everything */ nl_sock_init(c, false); - if (!v6_only) + if (!v6_only && !c->no_tap) c->ifi4 = conf_ip4(ifi4, &c->ip4); - if (!v4_only) + if (!v4_only && !c->no_tap) c->ifi6 = conf_ip6(ifi6, &c->ip6); if (c->ifi4 && c->mtu < IPV4_MIN_MTU) { @@ -1998,30 +2022,32 @@ void conf(struct ctx *c, int argc, char **argv) (*c->ip6.ifname_out && !c->ifi6)) die("External interface not usable"); - if (!c->ifi4 && !c->ifi6 && !*c->pasta_ifn) { + if (!c->ifi4 && !c->ifi6 && !*c->pasta_ifn && !c->no_tap) { strncpy(c->pasta_ifn, pasta_default_ifn, sizeof(c->pasta_ifn) - 1); } if (!c->ifi4 && !v6_only) { - info("IPv4: no external interface as template, use local mode"); - - conf_ip4_local(&c->ip4); + if (!c->no_tap) { + info("IPv4: no external interface as template, use local mode"); + conf_ip4_local(&c->ip4); + } c->ifi4 = -1; } if (!c->ifi6 && !v4_only) { - info("IPv6: no external interface as template, use local mode"); - - conf_ip6_local(&c->ip6); + if (!c->no_tap) { + info("IPv6: no external interface as template, use local mode"); + conf_ip6_local(&c->ip6); + } c->ifi6 = -1; } - if (c->ifi4 && !no_map_gw && + if (c->ifi4 > 0 && !no_map_gw && IN4_IS_ADDR_UNSPECIFIED(&c->ip4.map_host_loopback)) c->ip4.map_host_loopback = c->ip4.guest_gw; - if (c->ifi6 && !no_map_gw && + if (c->ifi6 > 0 && !no_map_gw && IN6_IS_ADDR_UNSPECIFIED(&c->ip6.map_host_loopback)) c->ip6.map_host_loopback = c->ip6.guest_gw; @@ -2116,10 +2142,10 @@ void conf(struct ctx *c, int argc, char **argv) conf_ports(c, name, optarg, &c->udp.fwd_out); } while (name != -1); - if (!c->ifi4) + if (c->ifi4 <= 0) c->no_dhcp = 1; - if (!c->ifi6) { + if (c->ifi6 <= 0) { c->no_ndp = 1; c->no_dhcpv6 = 1; } else if (IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addr)) { diff --git a/fwd.c b/fwd.c index 44a0e10..2f4a89a 100644 --- a/fwd.c +++ b/fwd.c @@ -780,6 +780,9 @@ uint8_t fwd_nat_from_host(const struct ctx *c, uint8_t proto, return PIF_SPLICE; } + if (c->no_tap) + return PIF_NONE; + if (!nat_inbound(c, &ini->eaddr, &tgt->oaddr)) { if (inany_v4(&ini->eaddr)) { if (IN4_IS_ADDR_UNSPECIFIED(&c->ip4.our_tap_addr)) diff --git a/passt.1 b/passt.1 index db0d662..2d643f7 100644 --- a/passt.1 +++ b/passt.1 @@ -755,6 +755,11 @@ Default is to let the tap driver build a pseudorandom hardware address. Disable the bypass path for inbound, local traffic. See the section \fBHandling of local traffic in pasta\fR in the \fBNOTES\fR for more details. +.TP +.BR \-\-no-tap +Do not create a tap device in the namespace. In this mode, only local loopback +traffic between namespaces is forwarded using splice. + .SH EXAMPLES .SS \fBpasta diff --git a/passt.h b/passt.h index 79d01dd..0c1ec4c 100644 --- a/passt.h +++ b/passt.h @@ -200,6 +200,7 @@ struct ip6_ctx { * @no_ndp: Disable NDP handler altogether * @no_ra: Disable router advertisements * @no_splice: Disable socket splicing for inbound traffic + * @no_tap: Do not create tap device * @host_lo_to_ns_lo: Map host loopback addresses to ns loopback addresses * @freebind: Allow binding of non-local addresses for forwarding * @low_wmem: Low probed net.core.wmem_max @@ -277,6 +278,7 @@ struct ctx { int no_ndp; int no_ra; int no_splice; + int no_tap; int host_lo_to_ns_lo; int freebind; diff --git a/pasta.c b/pasta.c index 0ddd6b0..3510ec5 100644 --- a/pasta.c +++ b/pasta.c @@ -316,6 +316,9 @@ void pasta_ns_conf(struct ctx *c) die("Couldn't bring up loopback interface in namespace: %s", strerror_(-rc)); + if (c->no_tap) + return; + /* Get or set MAC in target namespace */ if (MAC_IS_ZERO(c->guest_mac)) nl_link_get_mac(nl_sock_ns, c->pasta_ifi, c->guest_mac); diff --git a/tap.c b/tap.c index 9d1344b..9b4eedc 100644 --- a/tap.c +++ b/tap.c @@ -1491,13 +1491,16 @@ static int tap_ns_tun(void *arg) */ static void tap_sock_tun_init(struct ctx *c) { - NS_CALL(tap_ns_tun, c); - if (c->fd_tap == -1) - die("Failed to set up tap device in namespace"); + if (!c->no_tap) { + NS_CALL(tap_ns_tun, c); + if (c->fd_tap == -1) + die("Failed to set up tap device in namespace"); + } pasta_ns_conf(c); - tap_start_connection(c); + if (!c->no_tap) + tap_start_connection(c); } /** -- 2.49.0

4 23

[PATCH 3/3] igmp: Remove apparently unneeded suppression
by David Gibson 14 Jan '26

14 Jan '26

cppcheck-2.19.1 complains that the unusedFunction suppression in igmp.c doesn't match. That seems like a cppcheck bug, because the function clearly *is* unused. The function exists because otherwise the compiler fails because "ISO C forbids an empty translation unit". mld.c contains an identical unused definition for the same reason, but without the suppression. It doesn't seem to have caused unusedFunction warnings, so maybe cppcheck counts the non-empty translation unit requirement as a "use" of the function? In any case, since omitting the suppression in mld.c seems to be fine, do the same in igmp.c to stop the complaints. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- igmp.c | 1 - 1 file changed, 1 deletion(-) diff --git a/igmp.c b/igmp.c index 0e775843..a3971fc6 100644 --- a/igmp.c +++ b/igmp.c @@ -13,5 +13,4 @@ */ /* TO BE IMPLEMENTED */ -/* cppcheck-suppress unusedFunction */ __attribute__((__unused__)) static void unused(void) { } -- 2.52.0

2 2

[PATCH v3 00/14] Introduce forwarding table
by David Gibson 14 Jan '26

14 Jan '26

This creates a new data structure for recording our port forwarding: a table of individual forwarding rules. This is intended to replace the existing forwarding mode, map and delta structures. For now, only the delta[] array is removed. map is still used, but only for automatic forwards. Mode is still used, but only has significance during configuration. There's still a lot that can be done for flexible forwarding, but this introduces the core data structure, and does enough to fix at least one concrete defect with the current logic (bug 187). I think it would be a good point to give it a solid review and maybe merge. I'm aware that this is a very large complex series, that will be difficult to review. I think that's more or less inevitable implementing a feature as broad and complex as "flexible forwarding". If it helps at all, I'm fine if it's not reviewed all at once - I won't assume review is complete until either you say so, or I get comments or R-b on each patch. This applies on top of all 3 of my outstanding series in this area: "Allow listen functions to return fds", "Clean ups to epoll references" (v2) and "Small cleanups to splice forwarding logic". David Gibson (14): inany: Extend inany_ntop() to treat NULL as a fully unspecified address conf, fwd: Keep a table of our port forwarding configuration conf: Accurately record ifname and address for outbound forwards conf, fwd: Record "auto" port forwards in forwarding table fwd: Make space to store listening sockets in forward table ip: Add ipproto_name() function fwd, tcp, udp: Set up listening sockets based on forward table tcp, udp: Remove old auto-forwarding socket arrays conf, fwd: Check forwarding table for conflicting rules fwd: Generate auto-forward exclusions from socket fd tables flow, fwd: Consult rules table when forwarding a new flow from socket fwd: Remap ports based directly on forwarding rule fwd, tcp, udp: Add forwarding rule to listening socket epoll references flow, fwd: Optimise forwarding rule lookup using epoll ref when possible conf.c | 118 +++++++++------ flow.c | 59 ++++++-- flow_table.h | 2 +- fwd.c | 379 ++++++++++++++++++++++++++++++++++++++++++++++--- fwd.h | 68 ++++++++- icmp.c | 2 +- inany.c | 28 +++- inany.h | 1 + ip.c | 26 ++++ ip.h | 2 + tcp.c | 154 ++------------------ tcp.h | 6 +- udp.c | 147 +++---------------- udp.h | 7 +- udp_flow.c | 14 +- udp_flow.h | 2 +- udp_internal.h | 4 +- 17 files changed, 641 insertions(+), 378 deletions(-) -- 2.52.0

3 39

[PATCH v3 0/6] flow: Introduce flow_epoll_set() to centralize epoll operations
by Laurent Vivier 14 Jan '26

14 Jan '26

Currently, each protocol handler (TCP, TCP splice, ICMP/ping, UDP) has its own code to add or modify file descriptors in epoll. This leads to duplicated boilerplate across icmp.c, tcp.c, tcp_splice.c, and udp_flow.c, with each setting up epoll_ref unions and calling epoll_ctl() with flow-type-specific details. This series introduces flow_epoll_set() in flow.c to handle epoll operations for all flow types in a unified way. The function derives the epoll type from the flow type via a mapping array, providing a simpler interface where the caller only needs to pass the flow, command, events, file descriptor, and side index. The API is: int flow_epoll_set(const struct flow_common *f, int command, uint32_t events, int fd, unsigned int sidei); This centralized approach will be essential for queue pair migration in the upcoming multithreading work, where flows need to be moved between different epoll instances owned by different threads. Preparatory patches: - Patch 1 removes dead timer update code in tcp_epoll_ctl() - Patch 2 refactors TCP timer creation to use epoll_add() helper - Patch 3 removes unneeded epoll_ref indirection in udp_flow - Patch 4 refactors udp_flow_sock() to assign the socket internally - Patch 5 refactors tcp_splice_conn_epoll_events() to per-side computation Core patch: - Patch 6 introduces flow_epoll_set() used by all protocol handlers Changes in v3: - Added patch 2: "tcp: cleanup timer creation" refactoring tcp_timer_ctl() to use epoll_add() helper with improved error handling - Removed epoll type parameter from flow_epoll_set(): the type is now derived from the flow type via a new flow_epoll[] mapping array - Simplified function signature to flow_epoll_set(f, command, events, fd, sidei) - TCP timer no longer uses flow_epoll_set(), uses epoll_add() directly - Added Reviewed-by from David Gibson to patches 1 and 3 - Series now 6 patches (was 5) Changes in v2: - Added patch 1: Remove dead timer update in tcp_epoll_ctl() since flow table compaction was eliminated - Added patch 2: Remove unnecessary epoll_ref indirection in udp_flow.c - Dropped v1 patch 6 (compute events inside flow_epoll_set()) - Dropped v1 patch 7 (retrieve fd from flow structure) - Added epoll_ctl() command parameter (EPOLL_CTL_ADD/EPOLL_CTL_MOD) - Callers must set epollfd via flow_epollid_set() before calling flow_epoll_set() - Removed FLOW_EPOLL_TIMER_ADD/FLOW_EPOLL_TIMER_MOD constants - Reduced series from 7 to 5 patches Laurent Vivier (6): tcp: remove timer update in tcp_epoll_ctl() tcp: cleanup timer creation udp_flow: remove unneeded epoll_ref indirection udp_flow: Assign socket to flow inside udp_flow_sock() tcp_splice: Refactor tcp_splice_conn_epoll_events() to per-side computation flow: Introduce flow_epoll_set() to centralize epoll operations flow.c | 37 +++++++++++++++++ flow.h | 2 + icmp.c | 10 ++--- tcp.c | 88 ++++++++++++++++++++-------------------- tcp_splice.c | 111 +++++++++++++++++++++++---------------------------- udp_flow.c | 18 +++------ 6 files changed, 140 insertions(+), 126 deletions(-) -- 2.52.0

3 9

[PATCH 0/3] cppcheck-2.19.1 fixes
by David Gibson 14 Jan '26

14 Jan '26

Here are some more fixes for cppcheck warnings that I'm seeing with cppcheck-2.19.1. One looks like it might, at least theoretically be a real bug. I'm not certain if all of these are due to a new cppcheck version, or if some are just due to things merged recently that hadn't previously been checked with a recent-ish version. David Gibson (3): treewide: Fix more pointers which can be const epoll_ctl: Move u64 variant first for safer initialisation igmp: Remove apparently unneeded suppression conf.c | 2 +- dhcpv6.c | 3 ++- epoll_ctl.h | 4 ++-- igmp.c | 1 - vhost_user.c | 2 +- 5 files changed, 6 insertions(+), 6 deletions(-) -- 2.52.0

2 1

[PATCH v2 0/2] Allow listen functions to return fds
by David Gibson 14 Jan '26

14 Jan '26

For future forwarding changes, it makes more sense for the tcp and udp listen functions to return socket fds, rather than just success / failure. Make the change, fixing bug 186 along the way. Link: https://bugs.passt.top/show_bug.cgi?id=186 Changes in v2: * Fix several typos in comments and commit messages * Drop the --no-bindtodevice option, I was convinced it wasn't useful enough * Change from -EACCES to -EAFNOSUPPORT error code David Gibson (2): tcp, udp, conf: Don't silently ignore listens on unsupported IP versions tcp, udp: Make {tcp,udp}_listen() return socket fds conf.c | 24 +++++++++++++++++------- tcp.c | 13 ++++--------- udp.c | 10 ++++------ 3 files changed, 25 insertions(+), 22 deletions(-) -- 2.52.0

2 3

[PATCH] apparmor: Upgrade ABI version to 4.0, explicitly enable user namespace creation
by Stefano Brivio 13 Jan '26

13 Jan '26

In the 3.0 AppArmor ABI version we currently use, user namespace rules are not supported, and, as long as we load confined profiles, those implicitly allow creation of user namespaces. However, ABI version 4.0 introduces rules for user namespaces, and if we don't specify any, we can't create user namespaces, see: https://gitlab.com/apparmor/apparmor/-/wikis/unprivileged_userns_restriction This wouldn't affect us in general, given that we're using the 3.0 ABI, but libvirt's policy uses 4.0 instead, and if our abstractions are used from there, no matter what ABI policy version we declare, rules for user namespace creation now match ABI policy version 4.0. As a result, when libvirtd runs as root, and its profile includes passt's abstraction, cf. commit 66769c2de825 ("apparmor: Workaround for unconfined libvirtd when triggered by unprivileged user"), passt can't detach user namespaces and will fail to start, as reported by Niklas: ERROR internal error: Child process (passt --one-off --socket /run/libvirt/qemu/passt/1-haos-net0.socket --pid /run/libvirt/qemu/passt/1-haos-net0-passt.pid --tcp-ports 8123) unexpected exit status 1: Multiple interfaces with IPv6 routes, picked first UNIX domain socket bound at /run/libvirt/qemu/passt/1-haos-net0.socket Couldn't create user namespace: Permission denied This isn't a problem with libvirtd running as regular user, because in that case, as a workaround, passt currently runs under its own profile, not as a libvirtd subprofile (see commit referenced above). Given that ABI 4.0 has been around for a while, being introduced in July 2023, finally take the step to upgrade to it and explicitly enable user namespace creation. No further changes are needed in the existing policies to match new features introduced in AppArmor 4.0. Reported-by: Niklas Edmundsson <nikke(a)accum.se> Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1124801 Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com> --- contrib/apparmor/abstractions/passt | 3 ++- contrib/apparmor/abstractions/pasta | 2 +- contrib/apparmor/usr.bin.passt | 2 +- contrib/apparmor/usr.bin.passt-repair | 2 +- contrib/apparmor/usr.bin.pasta | 2 +- 5 files changed, 6 insertions(+), 5 deletions(-) diff --git a/contrib/apparmor/abstractions/passt b/contrib/apparmor/abstractions/passt index 25b2ea8..0ffadaf 100644 --- a/contrib/apparmor/abstractions/passt +++ b/contrib/apparmor/abstractions/passt @@ -11,7 +11,7 @@ # Copyright (c) 2022 Red Hat GmbH # Author: Stefano Brivio <sbrivio(a)redhat.com> - abi <abi/3.0>, + abi <abi/4.0>, include <abstractions/base> @@ -24,6 +24,7 @@ capability setpcap, capability net_admin, capability sys_ptrace, + userns, / r, # isolate_prefork(), isolation.c mount options=(rw, runbindable) -> /, diff --git a/contrib/apparmor/abstractions/pasta b/contrib/apparmor/abstractions/pasta index 9f73bee..251d4a2 100644 --- a/contrib/apparmor/abstractions/pasta +++ b/contrib/apparmor/abstractions/pasta @@ -11,7 +11,7 @@ # Copyright (c) 2022 Red Hat GmbH # Author: Stefano Brivio <sbrivio(a)redhat.com> - abi <abi/3.0>, + abi <abi/4.0>, include <abstractions/passt> diff --git a/contrib/apparmor/usr.bin.passt b/contrib/apparmor/usr.bin.passt index 62a4514..c123a86 100644 --- a/contrib/apparmor/usr.bin.passt +++ b/contrib/apparmor/usr.bin.passt @@ -11,7 +11,7 @@ # Copyright (c) 2022 Red Hat GmbH # Author: Stefano Brivio <sbrivio(a)redhat.com> -abi <abi/3.0>, +abi <abi/4.0>, include <tunables/global> diff --git a/contrib/apparmor/usr.bin.passt-repair b/contrib/apparmor/usr.bin.passt-repair index 901189d..23ff1ce 100644 --- a/contrib/apparmor/usr.bin.passt-repair +++ b/contrib/apparmor/usr.bin.passt-repair @@ -11,7 +11,7 @@ # Copyright (c) 2025 Red Hat GmbH # Author: Stefano Brivio <sbrivio(a)redhat.com> -abi <abi/3.0>, +abi <abi/4.0>, #include <tunables/global> diff --git a/contrib/apparmor/usr.bin.pasta b/contrib/apparmor/usr.bin.pasta index 2483968..56b5024 100644 --- a/contrib/apparmor/usr.bin.pasta +++ b/contrib/apparmor/usr.bin.pasta @@ -11,7 +11,7 @@ # Copyright (c) 2022 Red Hat GmbH # Author: Stefano Brivio <sbrivio(a)redhat.com> -abi <abi/3.0>, +abi <abi/4.0>, include <tunables/global> -- 2.43.0

2 4

[PATCH 1/3] conf: Introduce --no-bindtodevice option for testing
by David Gibson 13 Jan '26

13 Jan '26

We need to support (as best we can) older kernels which don't allow unprivilieged processes to use the SO_BINDTODEVICE socket option. Fallcaks for that case are controlled by the c->no_bindtodevice variable. Currently testing behaviour of those fallbacks requires setting up a test system with a kernel that doesn't support the option, which is pretty awkward. We can test it almost as well and much more easily by adding a command line option to explicitly disable use of SO_BINDTODEVICE. Like --no-splice this is envisaged as something for developers' and testers' convenience, not a supported option for end users. The man page text reflects that. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- conf.c | 2 ++ passt.1 | 6 ++++++ 2 files changed, 8 insertions(+) diff --git a/conf.c b/conf.c index ceb9aa55..70ea168c 100644 --- a/conf.c +++ b/conf.c @@ -962,6 +962,7 @@ static void usage(const char *name, FILE *f, int status) " --no-ndp Disable NDP responses\n" " --no-dhcpv6 Disable DHCPv6 server\n" " --no-ra Disable router advertisements\n" + " --no-bindtodevice Disable SO_BINDTODEVICE\n" " --freebind Bind to any address for forwarding\n" " --no-map-gw Don't map gateway address to host\n" " -4, --ipv4-only Enable IPv4 operation only\n" @@ -1454,6 +1455,7 @@ void conf(struct ctx *c, int argc, char **argv) {"no-dhcpv6", no_argument, &c->no_dhcpv6, 1 }, {"no-ndp", no_argument, &c->no_ndp, 1 }, {"no-ra", no_argument, &c->no_ra, 1 }, + {"no-bindtodevice", no_argument, &c->no_bindtodevice, 1}, {"no-splice", no_argument, &c->no_splice, 1 }, {"freebind", no_argument, &c->freebind, 1 }, {"no-map-gw", no_argument, &no_map_gw, 1 }, diff --git a/passt.1 b/passt.1 index db0d6620..4859d9e5 100644 --- a/passt.1 +++ b/passt.1 @@ -348,6 +348,12 @@ namespace will be silently dropped. Disable Router Advertisements. Router Solicitations coming from guest or target namespace will be ignored. +.TP +.BR \-\-no-bindtodevice +Development/testing option, do not use. Disables use of +SO_BINDTODEVICE socket option. Implicitly enabled on older kernels +which don't permit unprivileged use of SO_BINDTODEVICE. + .TP .BR \-\-freebind Allow any binding address to be specified for \fB-t\fR and \fB-u\fR -- 2.52.0

2 5

[PATCH 2/3] epoll_ctl: Move u64 variant first for safer initialisation
by David Gibson 13 Jan '26

13 Jan '26

cppcheck-2.19.1 pointed out that an initialiser like: union epoll_ref foo = { 0 }; doesn't necessarily zero the whole union, because the first variant listed may not be the full length. I don't think this is actually broken in practice, but I'm not 100% certain about that. In any case, make it more clearly correct, and stop cppcheck complaining by moving the @u64 variant to be the first one. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- epoll_ctl.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/epoll_ctl.h b/epoll_ctl.h index 3f802e76..2c103cde 100644 --- a/epoll_ctl.h +++ b/epoll_ctl.h @@ -17,6 +17,7 @@ /** * union epoll_ref - Breakdown of reference for epoll fd bookkeeping + * @u64: Opaque reference for epoll_ctl() and epoll_wait() * @type: Type of fd (tells us what to do with events) * @fd: File descriptor number (implies < 2^24 total descriptors) * @flow: Index of the flow this fd is linked to @@ -25,9 +26,9 @@ * @data: Data handled by protocol handlers * @nsdir_fd: netns dirfd for fallback timer checking if namespace is gone * @queue: vhost-user queue index for this fd - * @u64: Opaque reference for epoll_ctl() and epoll_wait() */ union epoll_ref { + uint64_t u64; struct { enum epoll_type type:8; int32_t fd:FD_REF_BITS; @@ -40,7 +41,6 @@ union epoll_ref { int queue; }; }; - uint64_t u64; }; static_assert(sizeof(union epoll_ref) <= sizeof(union epoll_data), "epoll_ref must have same size as epoll_data"); -- 2.52.0

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