mirror of
https://git.robbyzambito.me/zaprus/
synced 2026-02-04 03:34:48 +00:00
Move RawSocket and clean it up
This commit is contained in:
161
src/RawSocket.zig
Normal file
161
src/RawSocket.zig
Normal file
@@ -0,0 +1,161 @@
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const RawSocket = @This();
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fd: i32,
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sockaddr_ll: std.posix.sockaddr.ll,
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mac: [6]u8,
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const Ifconf = extern struct {
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ifc_len: i32,
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ifc_ifcu: extern union {
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ifcu_buf: ?[*]u8,
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ifcu_req: ?[*]std.os.linux.ifreq,
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},
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};
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pub fn init() !RawSocket {
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const socket: i32 = @intCast(std.os.linux.socket(std.os.linux.AF.PACKET, std.os.linux.SOCK.RAW, 0));
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if (socket < 0) return error.SocketError;
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var ifreq_storage: [16]std.os.linux.ifreq = undefined;
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var ifc = Ifconf{
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.ifc_len = @sizeOf(@TypeOf(ifreq_storage)),
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.ifc_ifcu = .{ .ifcu_req = &ifreq_storage },
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};
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if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFCONF, @intFromPtr(&ifc)) != 0) {
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return error.NicError;
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}
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const count = @divExact(ifc.ifc_len, @sizeOf(std.os.linux.ifreq));
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// Get the first non loopback interface
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var ifr = for (ifreq_storage[0..@intCast(count)]) |*ifr| {
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if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFFLAGS, @intFromPtr(ifr)) == 0) {
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if (ifr.ifru.flags.LOOPBACK) continue;
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break ifr;
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}
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} else return error.NoInterfaceFound;
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// 2. Get Interface Index
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if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFINDEX, @intFromPtr(ifr)) != 0) {
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return error.NicError;
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}
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const ifindex: i32 = ifr.ifru.ivalue;
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// 3. Get Real MAC Address
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if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFHWADDR, @intFromPtr(ifr)) != 0) {
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return error.NicError;
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}
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var mac: [6]u8 = ifr.ifru.hwaddr.data[0..6].*;
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if (builtin.cpu.arch.endian() == .little) std.mem.reverse(u8, &mac);
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// 4. Set Flags (Promiscuous/Broadcast)
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if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFFLAGS, @intFromPtr(ifr)) != 0) {
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return error.NicError;
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}
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ifr.ifru.flags.BROADCAST = true;
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ifr.ifru.flags.PROMISC = true;
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if (std.os.linux.ioctl(socket, std.os.linux.SIOCSIFFLAGS, @intFromPtr(ifr)) != 0) {
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return error.NicError;
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}
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const sockaddr_ll = std.mem.zeroInit(std.posix.sockaddr.ll, .{
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.family = std.posix.AF.PACKET,
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.ifindex = ifindex,
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.protocol = std.mem.nativeToBig(u16, @as(u16, std.os.linux.ETH.P.IP)),
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});
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const bind_ret = std.os.linux.bind(socket, @ptrCast(&sockaddr_ll), @sizeOf(@TypeOf(sockaddr_ll)));
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if (bind_ret != 0) return error.BindError;
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const timeout: std.os.linux.timeval = .{ .sec = 600, .usec = 0 };
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const timeout_ret = std.os.linux.setsockopt(socket, std.os.linux.SOL.SOCKET, std.os.linux.SO.RCVTIMEO, @ptrCast(&timeout), @sizeOf(@TypeOf(timeout)));
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if (timeout_ret != 0) return error.SetTimeoutError;
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return .{
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.fd = socket,
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.sockaddr_ll = sockaddr_ll,
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.mac = mac,
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};
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}
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pub fn deinit(self: *RawSocket) void {
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_ = std.os.linux.close(self.fd);
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self.* = undefined;
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}
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pub fn send(self: RawSocket, payload: []const u8) !void {
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const sent_bytes = std.os.linux.sendto(
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self.fd,
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payload.ptr,
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payload.len,
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0,
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@ptrCast(&self.sockaddr_ll),
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@sizeOf(@TypeOf(self.sockaddr_ll)),
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);
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_ = sent_bytes;
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}
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pub fn receive(self: RawSocket, buf: []u8) ![]u8 {
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const len = std.os.linux.recvfrom(
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self.fd,
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buf.ptr,
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buf.len,
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0,
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null,
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null,
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);
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if (std.os.linux.errno(len) != .SUCCESS) {
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return error.Timeout; // TODO: get the real error, assume timeout for now.
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}
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return buf[0..len];
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}
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pub fn attachSaprusPortFilter(self: RawSocket, port: u16) !void {
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const BPF = std.os.linux.BPF;
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// BPF instruction structure for classic BPF
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const SockFilter = extern struct {
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code: u16,
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jt: u8,
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jf: u8,
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k: u32,
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};
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const SockFprog = extern struct {
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len: u16,
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filter: [*]const SockFilter,
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};
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// Build the filter program
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const filter = [_]SockFilter{
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// Load 2 bytes at offset 46 (absolute)
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.{ .code = BPF.LD | BPF.H | BPF.ABS, .jt = 0, .jf = 0, .k = 46 },
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// Jump if equal to port (skip 0 if true, skip 1 if false)
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.{ .code = BPF.JMP | BPF.JEQ | BPF.K, .jt = 0, .jf = 1, .k = @as(u32, port) },
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// Return 0xffff (pass)
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.{ .code = BPF.RET | BPF.K, .jt = 0, .jf = 0, .k = 0xffff },
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// Return 0x0 (fail)
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.{ .code = BPF.RET | BPF.K, .jt = 0, .jf = 0, .k = 0x0 },
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};
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const fprog = SockFprog{
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.len = filter.len,
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.filter = &filter,
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};
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// Attach filter to socket using setsockopt
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const rc = std.os.linux.setsockopt(
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self.fd,
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std.os.linux.SOL.SOCKET,
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std.os.linux.SO.ATTACH_FILTER,
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@ptrCast(&fprog),
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@sizeOf(SockFprog),
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);
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if (rc != 0) {
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return error.BpfAttachFailed;
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}
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}
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const std = @import("std");
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const builtin = @import("builtin");
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185
src/main.zig
185
src/main.zig
@@ -229,6 +229,7 @@ pub fn main(init: std.process.Init) !void {
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var res_buf: [4096]u8 = undefined;
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var res = socket.receive(&res_buf) catch continue;
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try init.io.sleep(.fromMilliseconds(40), .real);
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headers.udp.dst_port = udp_dest_port;
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headers.ip.id = rand.int(u16);
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@@ -244,6 +245,7 @@ pub fn main(init: std.process.Init) !void {
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while (true) {
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res = socket.receive(&res_buf) catch continue :reconnect;
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try init.io.sleep(.fromMilliseconds(40), .real);
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const connection_res = blk: {
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const msg: SaprusMessage = try .parse(res[42..]);
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break :blk msg.connection;
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@@ -320,187 +322,6 @@ const RawSocketWriter = zaprus.RawSocketWriter;
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const AF = std.os.linux.AF;
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const SOCK = std.os.linux.SOCK;
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const RawSocket = struct {
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fd: i32,
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sockaddr_ll: std.posix.sockaddr.ll,
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mac: [6]u8,
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const IFF_LOOPBACK = 0x8;
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const ifconf = extern struct {
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ifc_len: i32,
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ifc_ifcu: extern union {
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ifcu_buf: ?[*]u8,
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ifcu_req: ?[*]std.os.linux.ifreq,
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},
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};
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fn init() !RawSocket {
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const socket: i32 = @intCast(std.os.linux.socket(std.posix.AF.PACKET, std.posix.SOCK.RAW, 0));
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if (socket < 0) return error.SocketError;
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// 1. Enumerate interfaces
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var ifreq_storage: [16]std.os.linux.ifreq = undefined;
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var ifc = ifconf{
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.ifc_len = @sizeOf(@TypeOf(ifreq_storage)),
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.ifc_ifcu = .{ .ifcu_req = &ifreq_storage },
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};
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if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFCONF, @intFromPtr(&ifc)) != 0) {
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return error.NicError;
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}
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const count = @divExact(ifc.ifc_len, @sizeOf(std.os.linux.ifreq));
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var target_ifr: ?std.os.linux.ifreq = null;
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for (ifreq_storage[0..@intCast(count)]) |ifr| {
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var temp_ifr = ifr;
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if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFFLAGS, @intFromPtr(&temp_ifr)) == 0) {
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// Cast the packed flags to u16 to match the kernel's ifr_flags size
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const flags: u16 = @bitCast(temp_ifr.ifru.flags);
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if (flags & IFF_LOOPBACK != 0) continue;
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target_ifr = ifr;
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break;
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}
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}
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var ifr = target_ifr orelse return error.NoInterfaceFound;
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// 2. Get Interface Index
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if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFINDEX, @intFromPtr(&ifr)) != 0) {
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return error.NicError;
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}
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const ifindex: i32 = ifr.ifru.ivalue;
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// 3. Get Real MAC Address
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if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFHWADDR, @intFromPtr(&ifr)) != 0) {
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return error.NicError;
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}
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var mac: [6]u8 = ifr.ifru.hwaddr.data[0..6].*;
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std.mem.reverse(u8, &mac);
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// 4. Set Flags (Promiscuous/Broadcast)
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if (std.os.linux.ioctl(socket, std.os.linux.SIOCGIFFLAGS, @intFromPtr(&ifr)) != 0) {
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return error.NicError;
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}
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ifr.ifru.flags.BROADCAST = true;
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ifr.ifru.flags.PROMISC = true;
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if (std.os.linux.ioctl(socket, std.os.linux.SIOCSIFFLAGS, @intFromPtr(&ifr)) != 0) {
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return error.NicError;
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}
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const sockaddr_ll = std.posix.sockaddr.ll{
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.family = std.posix.AF.PACKET,
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.ifindex = ifindex,
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.protocol = std.mem.nativeToBig(u16, @as(u16, std.os.linux.ETH.P.IP)),
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.halen = 0,
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.addr = .{ 0, 0, 0, 0, 0, 0, 0, 0 },
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.pkttype = 0,
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.hatype = 0,
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};
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const bind_ret = std.os.linux.bind(socket, @ptrCast(&sockaddr_ll), @sizeOf(@TypeOf(sockaddr_ll)));
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if (bind_ret != 0) return error.BindError;
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const timeout: std.os.linux.timeval = .{ .sec = 600, .usec = 0 };
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const timeout_ret = std.os.linux.setsockopt(socket, std.os.linux.SOL.SOCKET, std.os.linux.SO.RCVTIMEO, @ptrCast(&timeout), @sizeOf(@TypeOf(timeout)));
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if (timeout_ret != 0) return error.SetTimeoutError;
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return .{
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.fd = socket,
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.sockaddr_ll = sockaddr_ll,
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.mac = mac,
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};
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}
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fn deinit(self: *RawSocket) void {
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_ = std.os.linux.close(self.fd);
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self.* = undefined;
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}
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fn send(self: RawSocket, payload: []const u8) !void {
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const sent_bytes = std.os.linux.sendto(
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self.fd,
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payload.ptr,
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payload.len,
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0,
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@ptrCast(&self.sockaddr_ll),
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@sizeOf(@TypeOf(self.sockaddr_ll)),
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);
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_ = sent_bytes;
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}
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fn receive(self: RawSocket, buf: []u8) ![]u8 {
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const len = std.os.linux.recvfrom(
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self.fd,
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buf.ptr,
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buf.len,
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0,
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null,
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null,
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);
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if (std.os.linux.errno(len) != .SUCCESS) {
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return error.Timeout; // TODO: get the real error, assume timeout for now.
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}
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return buf[0..len];
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}
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fn attachSaprusPortFilter(self: RawSocket, port: u16) !void {
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const linux = std.os.linux;
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// BPF instruction structure for classic BPF
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const sock_filter = extern struct {
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code: u16,
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jt: u8,
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jf: u8,
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k: u32,
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};
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const sock_fprog = extern struct {
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len: u16,
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filter: [*]const sock_filter,
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};
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// BPF instruction opcodes
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const BPF_LD = 0x00;
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const BPF_H = 0x08; // Half-word (2 bytes)
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const BPF_ABS = 0x20;
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const BPF_JMP = 0x05;
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const BPF_JEQ = 0x10;
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const BPF_K = 0x00;
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const BPF_RET = 0x06;
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// Build the filter program
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const filter = [_]sock_filter{
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// Load 2 bytes at offset 46 (absolute)
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.{ .code = BPF_LD | BPF_H | BPF_ABS, .jt = 0, .jf = 0, .k = 46 },
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// Jump if equal to port (skip 0 if true, skip 1 if false)
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.{ .code = BPF_JMP | BPF_JEQ | BPF_K, .jt = 0, .jf = 1, .k = @as(u32, port) },
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// Return 0xffff (pass)
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.{ .code = BPF_RET | BPF_K, .jt = 0, .jf = 0, .k = 0xffff },
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// Return 0x0 (fail)
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.{ .code = BPF_RET | BPF_K, .jt = 0, .jf = 0, .k = 0x0 },
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};
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const fprog = sock_fprog{
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.len = filter.len,
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.filter = &filter,
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};
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// Attach filter to socket using setsockopt
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const SO_ATTACH_FILTER = 26;
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const rc = linux.setsockopt(
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self.fd,
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linux.SOL.SOCKET,
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SO_ATTACH_FILTER,
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@ptrCast(&fprog),
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@sizeOf(sock_fprog),
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);
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if (rc != 0) {
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return error.BpfAttachFailed;
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}
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}
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};
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const RawSocket = @import("./RawSocket.zig");
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const Writer = std.Io.Writer;
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Block a user