rwhod: react to audit pam events to broadcast updates

Listen to read-only audit packets from the kernel to react on user
logins/logouts. This way, we can immediately notify other machines on
the network whenever there is a change to the user session list.

Cargo.lock

@@ -56,7 +56,7 @@ version = "1.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "40c48f72fd53cd289104fc64099abca73db4166ad86ea0b4341abe65af83dadc"
 dependencies = [
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -67,7 +67,7 @@ checksum = "291e6a250ff86cd4a820112fb8898808a366d8f9f58ce16d1f538353ad55747d"
 dependencies = [
  "anstyle",
  "once_cell_polyfill",
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -205,9 +205,9 @@ dependencies = [
 
 [[package]]
 name = "clap"
-version = "4.6.2"
+version = "4.6.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dd059f9da4f5c36b3787f65d38ccaab1cc315f07b01f89abc8359ee6a8205011"
+checksum = "0fb99565819980999fb7b4a1796046a5c949e6d4ff132cf5fadf5a641e20d776"
 dependencies = [
  "clap_builder",
  "clap_derive",
@@ -237,9 +237,9 @@ dependencies = [
 
 [[package]]
 name = "clap_derive"
-version = "4.6.1"
+version = "4.6.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f2ce8604710f6733aa641a2b3731eaa1e8b3d9973d5e3565da11800813f997a9"
+checksum = "32f2392eae7f16557a3d727ef3a12e57b2b2ca6f98566a5f4fb41ffe305df077"
 dependencies = [
  "heck",
  "proc-macro2",
@@ -359,7 +359,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
 dependencies = [
  "libc",
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -440,12 +440,48 @@ dependencies = [
  "thiserror",
 ]
 
+[[package]]
+name = "futures"
+version = "0.3.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a88cf1f829d945f548cf8fec32c61b1f202b6d93b45848602fc02af4b12ad218"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "futures-executor",
+ "futures-io",
+ "futures-sink",
+ "futures-task",
+ "futures-util",
+]
+
+[[package]]
+name = "futures-channel"
+version = "0.3.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "262590f4fe6afeb0bc83be1daa64e52657fe185690a958af7f3ad0e92085c5ae"
+dependencies = [
+ "futures-core",
+ "futures-sink",
+]
+
 [[package]]
 name = "futures-core"
 version = "0.3.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2cd50c473c80f6d7c3670a752354b8e569b1a7cbfdc0419ec88e5edad85e0dc7"
 
+[[package]]
+name = "futures-executor"
+version = "0.3.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6754879cc9f2c66f88c6e5c35344bb0bdb0708b0352b1201815667c7eabc7458"
+dependencies = [
+ "futures-core",
+ "futures-task",
+ "futures-util",
+]
+
 [[package]]
 name = "futures-io"
 version = "0.3.33"
@@ -494,9 +530,13 @@ version = "0.3.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a77a90a256fce34da66415271e30f94ee91c57b04b8a2c042d9cf3220179deaa"
 dependencies = [
+ "futures-channel",
  "futures-core",
+ "futures-io",
  "futures-macro",
+ "futures-sink",
  "futures-task",
+ "memchr",
  "pin-project-lite",
  "slab",
 ]
@@ -742,6 +782,54 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "netlink-packet-audit"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ca9e80389b423ef073a74f393a57c37ffef7bcf058212c233412f19a026109b8"
+dependencies = [
+ "bytes",
+ "log",
+ "netlink-packet-core",
+ "netlink-proto",
+]
+
+[[package]]
+name = "netlink-packet-core"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3463cbb78394cb0141e2c926b93fc2197e473394b761986eca3b9da2c63ae0f4"
+dependencies = [
+ "paste",
+]
+
+[[package]]
+name = "netlink-proto"
+version = "0.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b65d130ee111430e47eed7896ea43ca693c387f097dd97376bffafbf25812128"
+dependencies = [
+ "bytes",
+ "futures",
+ "log",
+ "netlink-packet-core",
+ "netlink-sys",
+ "thiserror",
+]
+
+[[package]]
+name = "netlink-sys"
+version = "0.8.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cd6c30ed10fa69cc491d491b85cc971f6bdeb8e7367b7cde2ee6cc878d583fae"
+dependencies = [
+ "bytes",
+ "futures-util",
+ "libc",
+ "log",
+ "tokio",
+]
+
 [[package]]
 name = "nix"
 version = "0.31.3"
@@ -761,7 +849,7 @@ version = "0.50.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7957b9740744892f114936ab4a57b3f487491bbeafaf8083688b16841a4240e5"
 dependencies = [
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -815,6 +903,12 @@ version = "2.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f38d5652c16fde515bb1ecef450ab0f6a219d619a7274976324d5e377f7dceba"
 
+[[package]]
+name = "paste"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
+
 [[package]]
 name = "phf"
 version = "0.12.1"
@@ -929,6 +1023,9 @@ dependencies = [
  "futures-util",
  "indoc",
  "itertools",
+ "netlink-packet-audit",
+ "netlink-proto",
+ "netlink-sys",
  "nix",
  "sd-notify",
  "serde",
@@ -961,7 +1058,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys",
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -1018,14 +1115,14 @@ checksum = "e7a5d71263a5a7d47b41f6b3f06ba276f10cc18b0931f1799f710578e2309348"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 3.0.1",
+ "syn 3.0.2",
 ]
 
 [[package]]
 name = "serde_json"
-version = "1.0.150"
+version = "1.0.151"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e8014e44b4736ed0538adeecded0fce2a272f22dc9578a7eb6b2d9993c74cfb9"
+checksum = "c841b55ecdae098c80dcae9cf767f6f8a0c2cdb3416bbef72181df4d0fe73f14"
 dependencies = [
  "itoa",
  "memchr",
@@ -1093,7 +1190,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c3d1e2c7f27f8d4cb10542a02c49005dbd6e93095799d6f3be745fae9f8fedd4"
 dependencies = [
  "libc",
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -1115,9 +1212,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "3.0.1"
+version = "3.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5edbec4ed188954a10c12c038215f8ce7606b2d5c973cd8dc43e8795065c5f2f"
+checksum = "a207d6d6a2b7fc470b80443726053f18a2481b7e1eee970597051596567987a3"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1134,7 +1231,7 @@ dependencies = [
  "getrandom",
  "once_cell",
  "rustix",
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -1144,7 +1241,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "230a1b821ccbd75b185820a1f1ff7b14d21da1e442e22c0863ea5f08771a8874"
 dependencies = [
  "rustix",
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -1164,7 +1261,7 @@ checksum = "43cbfe0cf76104d42a574802844187e84a305e531ed54455f11fbde0f10541cd"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 3.0.1",
+ "syn 3.0.2",
 ]
 
 [[package]]