Auto merge of #3420 - elecm:main, r=JohnTitor

feat: add GSO flags for linux and android

Add Generic Segmentation Offload (GSO) flags based on [if_tun.h](https://github.com/torvalds/linux/blob/master/include/uapi/linux/if_tun.h#L87) header in Linux  and [if_tun.h](https://android.googlesource.com/platform/bionic/+/HEAD/libc/kernel/uapi/linux/if_tun.h#71) header in Android source code.
Include the `IFF_NO_CARRIER` flag as well (found in the same files mentioned in the previous paragraph).

There is a [PR](#3320 (comment)) similar to mine, but that PR doesn't include GSO flags for UDP (`TUN_F_USO4` and `TUN_F_USO6`), and it is only for Linux. And also, I used `c_uint`type for GSO flags because related ioctl function (`#define TUNSETOFFLOAD  _IOW('T', 208, unsigned int)`) get `unsigned int` but that PR uses `c_ushort`.

libc-test/build.rs

@@ -3855,6 +3855,9 @@ fn test_linux(target: &str) {
             // kernel 6.1 minimum
             "MADV_COLLAPSE" => true,
 
+            // kernel 6.2 minimum
+            "TUN_F_USO4" | "TUN_F_USO6" | "IFF_NO_CARRIER" => true,
+
             // FIXME: Requires more recent kernel headers
             | "IFLA_PARENT_DEV_NAME"     // linux v5.13+
             | "IFLA_PARENT_DEV_BUS_NAME" // linux v5.13+

libc-test/semver/android.txt

@@ -699,6 +699,7 @@ IFF_MASTER
 IFF_MULTICAST
 IFF_NOARP
 IFF_NOTRAILERS
+IFF_NO_CARRIER
 IFF_NO_PI
 IFF_POINTOPOINT
 IFF_PORTSEL
@@ -708,6 +709,13 @@ IFF_SLAVE
 IFF_TAP
 IFF_TUN
 IFF_UP
+TUN_F_CSUM
+TUN_F_TSO4
+TUN_F_TSO6
+TUN_F_TSO_ECN
+TUN_F_UFO
+TUN_F_USO4
+TUN_F_USO6
 IFNAMSIZ
 IF_NAMESIZE
 IFA_UNSPEC

libc-test/semver/linux.txt

@@ -932,6 +932,7 @@ IFF_LOWER_UP
 IFF_MASTER
 IFF_MULTICAST
 IFF_MULTI_QUEUE
+IFF_NO_CARRIER
 IFF_NOARP
 IFF_NOFILTER
 TUN_TX_TIMESTAMP
@@ -940,6 +941,8 @@ TUN_F_TSO4
 TUN_F_TSO6
 TUN_F_TSO_ECN
 TUN_F_UFO
+TUN_F_USO4
+TUN_F_USO6
 TUN_PKT_STRIP
 TUN_FLT_ALLMULTI
 IFF_NOTRAILERS

src/unix/linux_like/android/mod.rs

@@ -2481,6 +2481,7 @@ pub const IFF_TUN: ::c_int = 0x0001;
 pub const IFF_TAP: ::c_int = 0x0002;
 pub const IFF_NAPI: ::c_int = 0x0010;
 pub const IFF_NAPI_FRAGS: ::c_int = 0x0020;
+pub const IFF_NO_CARRIER: ::c_int = 0x0040;
 pub const IFF_NO_PI: ::c_int = 0x1000;
 pub const IFF_ONE_QUEUE: ::c_int = 0x2000;
 pub const IFF_VNET_HDR: ::c_int = 0x4000;
@@ -2490,6 +2491,14 @@ pub const IFF_ATTACH_QUEUE: ::c_int = 0x0200;
 pub const IFF_DETACH_QUEUE: ::c_int = 0x0400;
 pub const IFF_PERSIST: ::c_int = 0x0800;
 pub const IFF_NOFILTER: ::c_int = 0x1000;
+// Features for GSO (TUNSETOFFLOAD)
+pub const TUN_F_CSUM: ::c_uint = 0x01;
+pub const TUN_F_TSO4: ::c_uint = 0x02;
+pub const TUN_F_TSO6: ::c_uint = 0x04;
+pub const TUN_F_TSO_ECN: ::c_uint = 0x08;
+pub const TUN_F_UFO: ::c_uint = 0x10;
+pub const TUN_F_USO4: ::c_uint = 0x20;
+pub const TUN_F_USO6: ::c_uint = 0x40;
 
 // start android/platform/bionic/libc/kernel/uapi/linux/if_ether.h
 // from https://android.googlesource.com/platform/bionic/+/HEAD/libc/kernel/uapi/linux/if_ether.h

src/unix/linux_like/linux/mod.rs

@@ -1866,6 +1866,8 @@ pub const IFF_TUN: ::c_int = 0x0001;
 pub const IFF_TAP: ::c_int = 0x0002;
 pub const IFF_NAPI: ::c_int = 0x0010;
 pub const IFF_NAPI_FRAGS: ::c_int = 0x0020;
+// Used in TUNSETIFF to bring up tun/tap without carrier
+pub const IFF_NO_CARRIER: ::c_int = 0x0040;
 pub const IFF_NO_PI: ::c_int = 0x1000;
 // Read queue size
 pub const TUN_READQ_SIZE: ::c_short = 500;
@@ -1886,11 +1888,13 @@ pub const IFF_NOFILTER: ::c_int = 0x1000;
 // Socket options
 pub const TUN_TX_TIMESTAMP: ::c_int = 1;
 // Features for GSO (TUNSETOFFLOAD)
-pub const TUN_F_CSUM: ::c_ushort = 0x01; /* You can hand me unchecksummed packets. */
-pub const TUN_F_TSO4: ::c_ushort = 0x02; /* I can handle TSO for IPv4 packets */
-pub const TUN_F_TSO6: ::c_ushort = 0x04; /* I can handle TSO for IPv6 packets */
-pub const TUN_F_TSO_ECN: ::c_ushort = 0x08; /* I can handle TSO with ECN bits. */
-pub const TUN_F_UFO: ::c_ushort = 0x10; /* I can handle UFO packets */
+pub const TUN_F_CSUM: ::c_uint = 0x01;
+pub const TUN_F_TSO4: ::c_uint = 0x02;
+pub const TUN_F_TSO6: ::c_uint = 0x04;
+pub const TUN_F_TSO_ECN: ::c_uint = 0x08;
+pub const TUN_F_UFO: ::c_uint = 0x10;
+pub const TUN_F_USO4: ::c_uint = 0x20;
+pub const TUN_F_USO6: ::c_uint = 0x40;
 // Protocol info prepended to the packets (when IFF_NO_PI is not set)
 pub const TUN_PKT_STRIP: ::c_int = 0x0001;
 // Accept all multicast packets