diff --git a/docs/TRANSIENT-SETTINGS.md b/docs/TRANSIENT-SETTINGS.md
index d9b1c20c77f..f8282752973 100644
--- a/docs/TRANSIENT-SETTINGS.md
+++ b/docs/TRANSIENT-SETTINGS.md
@@ -429,6 +429,7 @@ Most socket unit settings are available to transient units.
✓ Broadcast=
✓ PassCredentials=
✓ PassSecurity=
+✓ PassPacketInfo=
✓ TCPCongestion=
✓ ReusePort=
✓ MessageQueueMaxMessages=
diff --git a/man/systemd.socket.xml b/man/systemd.socket.xml
index 60ea63f742a..46a2dbc7edf 100644
--- a/man/systemd.socket.xml
+++ b/man/systemd.socket.xml
@@ -709,6 +709,15 @@
Defaults to .
+
+ PassPacketInfo=
+ Takes a boolean value. This controls the IP_PKTINFO,
+ IPV6_RECVPKTINFO and NETLINK_PKTINFO socket options, which
+ enable reception of additional per-packet metadata as ancillary message, on
+ AF_INET, AF_INET6 and AF_UNIX sockets.
+ Defaults to .
+
+
TCPCongestion=
Takes a string value. Controls the TCP
diff --git a/src/basic/socket-util.c b/src/basic/socket-util.c
index 0be098df2ea..05dd7e70014 100644
--- a/src/basic/socket-util.c
+++ b/src/basic/socket-util.c
@@ -1174,5 +1174,27 @@ ssize_t recvmsg_safe(int sockfd, struct msghdr *msg, int flags) {
}
return n;
-
+}
+
+int socket_pass_pktinfo(int fd, bool b) {
+ int af;
+ socklen_t sl = sizeof(af);
+
+ if (getsockopt(fd, SOL_SOCKET, SO_DOMAIN, &af, &sl) < 0)
+ return -errno;
+
+ switch (af) {
+
+ case AF_INET:
+ return setsockopt_int(fd, IPPROTO_IP, IP_PKTINFO, b);
+
+ case AF_INET6:
+ return setsockopt_int(fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, b);
+
+ case AF_NETLINK:
+ return setsockopt_int(fd, SOL_NETLINK, NETLINK_PKTINFO, b);
+
+ default:
+ return -EAFNOSUPPORT;
+ }
}
diff --git a/src/basic/socket-util.h b/src/basic/socket-util.h
index 6f366c04299..9e02e398875 100644
--- a/src/basic/socket-util.h
+++ b/src/basic/socket-util.h
@@ -220,3 +220,5 @@ int socket_bind_to_ifname(int fd, const char *ifname);
int socket_bind_to_ifindex(int fd, int ifindex);
ssize_t recvmsg_safe(int sockfd, struct msghdr *msg, int flags);
+
+int socket_pass_pktinfo(int fd, bool b);
diff --git a/src/core/dbus-socket.c b/src/core/dbus-socket.c
index ad7b41a95b2..73e6a749147 100644
--- a/src/core/dbus-socket.c
+++ b/src/core/dbus-socket.c
@@ -104,6 +104,7 @@ const sd_bus_vtable bus_socket_vtable[] = {
SD_BUS_PROPERTY("Broadcast", "b", bus_property_get_bool, offsetof(Socket, broadcast), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("PassCredentials", "b", bus_property_get_bool, offsetof(Socket, pass_cred), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("PassSecurity", "b", bus_property_get_bool, offsetof(Socket, pass_sec), SD_BUS_VTABLE_PROPERTY_CONST),
+ SD_BUS_PROPERTY("PassPacketInfo", "b", bus_property_get_bool, offsetof(Socket, pass_pktinfo), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("RemoveOnStop", "b", bus_property_get_bool, offsetof(Socket, remove_on_stop), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("Listen", "a(ss)", property_get_listen, 0, SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("Symlinks", "as", NULL, offsetof(Socket, symlinks), SD_BUS_VTABLE_PROPERTY_CONST),
@@ -202,6 +203,9 @@ static int bus_socket_set_transient_property(
if (streq(name, "PassSecurity"))
return bus_set_transient_bool(u, name, &s->pass_sec, message, flags, error);
+ if (streq(name, "PassPacketInfo"))
+ return bus_set_transient_bool(u, name, &s->pass_pktinfo, message, flags, error);
+
if (streq(name, "ReusePort"))
return bus_set_transient_bool(u, name, &s->reuse_port, message, flags, error);
diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4
index 5fd58b379ba..c76d08b3a6d 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -396,6 +396,7 @@ Socket.Transparent, config_parse_bool, 0,
Socket.Broadcast, config_parse_bool, 0, offsetof(Socket, broadcast)
Socket.PassCredentials, config_parse_bool, 0, offsetof(Socket, pass_cred)
Socket.PassSecurity, config_parse_bool, 0, offsetof(Socket, pass_sec)
+Socket.PassPacketInfo, config_parse_bool, 0, offsetof(Socket, pass_pktinfo)
Socket.TCPCongestion, config_parse_string, 0, offsetof(Socket, tcp_congestion)
Socket.ReusePort, config_parse_bool, 0, offsetof(Socket, reuse_port)
Socket.MessageQueueMaxMessages, config_parse_long, 0, offsetof(Socket, mq_maxmsg)
diff --git a/src/core/socket.c b/src/core/socket.c
index 218b4b245df..359683a4261 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -635,6 +635,7 @@ static void socket_dump(Unit *u, FILE *f, const char *prefix) {
"%sBroadcast: %s\n"
"%sPassCredentials: %s\n"
"%sPassSecurity: %s\n"
+ "%sPassPacketInfo: %s\n"
"%sTCPCongestion: %s\n"
"%sRemoveOnStop: %s\n"
"%sWritable: %s\n"
@@ -654,6 +655,7 @@ static void socket_dump(Unit *u, FILE *f, const char *prefix) {
prefix, yes_no(s->broadcast),
prefix, yes_no(s->pass_cred),
prefix, yes_no(s->pass_sec),
+ prefix, yes_no(s->pass_pktinfo),
prefix, strna(s->tcp_congestion),
prefix, yes_no(s->remove_on_stop),
prefix, yes_no(s->writable),
@@ -1070,6 +1072,12 @@ static void socket_apply_socket_options(Socket *s, int fd) {
log_unit_warning_errno(UNIT(s), r, "SO_PASSSEC failed: %m");
}
+ if (s->pass_pktinfo) {
+ r = socket_pass_pktinfo(fd, true);
+ if (r < 0)
+ log_unit_warning_errno(UNIT(s), r, "Failed to enable packet info socket option: %m");
+ }
+
if (s->priority >= 0) {
r = setsockopt_int(fd, SOL_SOCKET, SO_PRIORITY, s->priority);
if (r < 0)
diff --git a/src/core/socket.h b/src/core/socket.h
index 9e0be15ba8d..482e45fce74 100644
--- a/src/core/socket.h
+++ b/src/core/socket.h
@@ -121,6 +121,7 @@ struct Socket {
bool broadcast;
bool pass_cred;
bool pass_sec;
+ bool pass_pktinfo;
/* Only for INET6 sockets: issue IPV6_V6ONLY sockopt */
SocketAddressBindIPv6Only bind_ipv6_only;
diff --git a/src/libsystemd/sd-netlink/netlink-socket.c b/src/libsystemd/sd-netlink/netlink-socket.c
index 71b3d1e2f1f..bcd82fe1646 100644
--- a/src/libsystemd/sd-netlink/netlink-socket.c
+++ b/src/libsystemd/sd-netlink/netlink-socket.c
@@ -16,10 +16,6 @@
#include "socket-util.h"
#include "util.h"
-/* For some reason we need some extra cmsg space on some kernels. It's not clear why, and one of those days
- * we need to track this down. See: https://github.com/systemd/systemd/pull/15457 */
-#define EXTRA_CMSG_SPACE 1024
-
int socket_open(int family) {
int fd;
@@ -244,7 +240,7 @@ int socket_write_message(sd_netlink *nl, sd_netlink_message *m) {
static int socket_recv_message(int fd, struct iovec *iov, uint32_t *ret_mcast_group, bool peek) {
union sockaddr_union sender;
- CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct nl_pktinfo)) + EXTRA_CMSG_SPACE) control;
+ CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct nl_pktinfo))) control;
struct msghdr msg = {
.msg_iov = iov,
.msg_iovlen = 1,
diff --git a/src/resolve/resolved-dns-stream.c b/src/resolve/resolved-dns-stream.c
index bbaffc165ac..1e2ff05c3e5 100644
--- a/src/resolve/resolved-dns-stream.c
+++ b/src/resolve/resolved-dns-stream.c
@@ -88,6 +88,7 @@ static int dns_stream_complete(DnsStream *s, int error) {
static int dns_stream_identify(DnsStream *s) {
CMSG_BUFFER_TYPE(CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo))
+ + CMSG_SPACE(int) + /* for the TTL */
+ EXTRA_CMSG_SPACE /* kernel appears to require extra space */) control;
struct msghdr mh = {};
struct cmsghdr *cmsg;
diff --git a/src/shared/bus-unit-util.c b/src/shared/bus-unit-util.c
index 3be75e6b4d2..9a5730f3eae 100644
--- a/src/shared/bus-unit-util.c
+++ b/src/shared/bus-unit-util.c
@@ -1632,6 +1632,7 @@ static int bus_append_socket_property(sd_bus_message *m, const char *field, cons
"Broadcast",
"PassCredentials",
"PassSecurity",
+ "PassPacketInfo",
"ReusePort",
"RemoveOnStop",
"SELinuxContextFromNet"))
diff --git a/test/fuzz/fuzz-unit-file/directives.service b/test/fuzz/fuzz-unit-file/directives.service
index 048bd34e9e2..7435d7abec0 100644
--- a/test/fuzz/fuzz-unit-file/directives.service
+++ b/test/fuzz/fuzz-unit-file/directives.service
@@ -164,6 +164,7 @@ PIDFile=
PartOf=
PassCredentials=
PassSecurity=
+PassPacketInfo=
PathChanged=
PathExists=
PathExistsGlob=
diff --git a/units/systemd-networkd.socket b/units/systemd-networkd.socket
index 445193e8d34..bc049e5ade9 100644
--- a/units/systemd-networkd.socket
+++ b/units/systemd-networkd.socket
@@ -17,7 +17,7 @@ Before=sockets.target
[Socket]
ReceiveBuffer=128M
ListenNetlink=route 1361
-PassCredentials=yes
+PassPacketInfo=yes
[Install]
WantedBy=sockets.target