I have an existing raw socket implementation that I am trying to move to AF_XDP based socket to see if I can get some increased performance. Does anyone have a basic example for how to create an XDP socket that just passes all frames (no filtering etc)?
Existing raw socket implementation
/// Raw socket implementation for LinkLayer
pub const RawSocket = struct {
send_mutex: std.Thread.Mutex = .{},
recv_mutex: std.Thread.Mutex = .{},
socket: std.posix.socket_t,
pub fn init(
ifname: [:0]const u8,
) !RawSocket {
if (ifname.len > std.posix.IFNAMESIZE - 1) return error.InterfaceNameTooLong;
assert(ifname.len <= std.posix.IFNAMESIZE - 1); // ifname too long
const ETH_P_ETHERCAT = @intFromEnum(telegram.EtherType.ETHERCAT);
const socket: std.posix.socket_t = try std.posix.socket(
std.posix.AF.PACKET,
std.posix.SOCK.RAW,
std.mem.nativeToBig(u32, ETH_P_ETHERCAT),
);
var timeout_rcv = std.posix.timeval{
.sec = 0,
.usec = 1,
};
try std.posix.setsockopt(
socket,
std.posix.SOL.SOCKET,
std.posix.SO.RCVTIMEO,
std.mem.asBytes(&timeout_rcv),
);
var timeout_snd = std.posix.timeval{
.sec = 0,
.usec = 1,
};
try std.posix.setsockopt(
socket,
std.posix.SOL.SOCKET,
std.posix.SO.SNDTIMEO,
std.mem.asBytes(&timeout_snd),
);
const dontroute_enable: c_int = 1;
try std.posix.setsockopt(
socket,
std.posix.SOL.SOCKET,
std.posix.SO.DONTROUTE,
std.mem.asBytes(&dontroute_enable),
);
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(socket, &ifr);
const ifindex: i32 = ifr.ifru.ivalue;
var rval = std.posix.errno(std.os.linux.ioctl(socket, std.os.linux.SIOCGIFFLAGS, @intFromPtr(&ifr)));
switch (rval) {
.SUCCESS => {},
else => {
return error.nicError;
},
}
ifr.ifru.flags.BROADCAST = true;
ifr.ifru.flags.PROMISC = true;
rval = std.posix.errno(std.os.linux.ioctl(socket, std.os.linux.SIOCSIFFLAGS, @intFromPtr(&ifr)));
switch (rval) {
.SUCCESS => {},
else => {
return error.nicError;
},
}
const sockaddr_ll = std.posix.sockaddr.ll{
.family = std.posix.AF.PACKET,
.ifindex = ifindex,
.protocol = std.mem.nativeToBig(u16, @as(u16, ETH_P_ETHERCAT)),
.halen = 0, //not used
.addr = .{ 0, 0, 0, 0, 0, 0, 0, 0 }, //not used
.pkttype = 0, //not used
.hatype = 0, //not used
};
try std.posix.bind(socket, @ptrCast(&sockaddr_ll), @sizeOf(@TypeOf(sockaddr_ll)));
return RawSocket{
.socket = socket,
};
}
pub fn deinit(self: *RawSocket) void {
std.posix.close(self.socket);
}
pub fn send(ctx: *anyopaque, bytes: []const u8) std.posix.SendError!void {
const self: *RawSocket = @ptrCast(@alignCast(ctx));
self.send_mutex.lock();
defer self.send_mutex.unlock();
_ = try std.posix.send(self.socket, bytes, 0);
}
pub fn recv(ctx: *anyopaque, out: []u8) std.posix.RecvFromError!usize {
const self: *RawSocket = @ptrCast(@alignCast(ctx));
self.recv_mutex.lock();
defer self.recv_mutex.unlock();
return try std.posix.recv(self.socket, out, std.posix.MSG.TRUNC);
}
pub fn linkLayer(self: *RawSocket) LinkLayer {
return LinkLayer{
.ptr = self,
.vtable = &.{ .send = send, .recv = recv },
};
}
};
I found xdp-tutorial/basic01-xdp-pass/xdp_pass_user.c at main · xdp-project/xdp-tutorial · GitHub
but its in C and seems to use a lot of libbpf which I don’t really know how to use in zig.