Flags for SIOC{G,S}IFFLAGS

[bentheklutz]

Adds a packed struct for SIOCGIFFLAGS and SIOCSIFFLAGS

Addresses #21890
Quick checked this with the following code.

const std = @import("std");

pub fn main() !void {
    const sock = try std.posix.socket(std.posix.AF.INET, std.posix.SOCK.STREAM, 0);
    const ifname = "wlp0s20f3";
    var ifr: std.posix.ifreq = std.mem.zeroInit(std.posix.ifreq, .{});
    @memcpy(ifr.ifrn.name[0..ifname.len], ifname);
    ifr.ifrn.name[ifname.len] = 0;
    try std.posix.ioctl_SIOCGIFINDEX(sock, &ifr);
    const rval = std.posix.errno(std.os.linux.ioctl(sock, std.os.linux.SIOCGIFFLAGS, @intFromPtr(&ifr)));
    if (rval != .SUCCESS) {
        return error.FlagsGetFailed;
    }

    std.debug.print("Flags set:\n", .{});

    if (ifr.ifru.flags.UP) {
        std.debug.print("UP\n", .{});
    }
    if (ifr.ifru.flags.BROADCAST) {
        std.debug.print("BROADCAST\n", .{});
    }
    if (ifr.ifru.flags.DEBUG) {
        std.debug.print("DEBUG\n", .{});
    }
    if (ifr.ifru.flags.LOOPBACK) {
        std.debug.print("LOOPBACK\n", .{});
    }
    if (ifr.ifru.flags.POINTOPOINT) {
        std.debug.print("POINTOPOINT\n", .{});
    }
    if (ifr.ifru.flags.NOTRAILERS) {
        std.debug.print("NOTRAILERS\n", .{});
    }
    if (ifr.ifru.flags.RUNNING) {
        std.debug.print("RUNNING\n", .{});
    }
    if (ifr.ifru.flags.NOARP) {
        std.debug.print("NOARP\n", .{});
    }
    if (ifr.ifru.flags.PROMISC) {
        std.debug.print("PROMISC\n", .{});
    }

    // requires elevated permissions to execute
    // ifr.ifru.flags.PROMISC = true;
    // ifr.ifru.flags.BROADCAST = true;

    // rval = std.posix.errno(std.os.linux.ioctl(sock, std.os.linux.SIOCSIFFLAGS, @intFromPtr(&ifr)));
    // switch (rval) {
    //     .SUCCESS => {},
    //     .PERM => return error.FailedPermissions,
    //     else => {},
    // }
}

[bentheklutz]

Should be actually good now. I didn't configure zig to use std from the compiler's source tree, so I was making changes in two places and not keeping them in sync.