From 4f721afcfd5db46b7d81b2ab1f9a827fec0b56cf Mon Sep 17 00:00:00 2001
From: Robby Zambito <contact@robbyzambito.me>
Date: Thu, 29 Jan 2026 23:13:04 -0500
Subject: Add GPLv3

---
 src/RawSocket.zig | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

(limited to 'src/RawSocket.zig')

diff --git a/src/RawSocket.zig b/src/RawSocket.zig
index 71b4e1c..5732ce9 100644
--- a/src/RawSocket.zig
+++ b/src/RawSocket.zig
@@ -1,3 +1,19 @@
+// Copyright 2026 Robby Zambito
+//
+// This file is part of zaprus.
+//
+// Zaprus is free software: you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the Free Software
+// Foundation, either version 3 of the License, or (at your option) any later
+// version.
+//
+// Zaprus is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+// A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with
+// Zaprus. If not, see <https://www.gnu.org/licenses/>.
+
 const RawSocket = @This();
 
 const is_debug = builtin.mode == .Debug;
-- 
cgit 


From 558f40213b895810a78b2bbcbdbb95e88a301fde Mon Sep 17 00:00:00 2001
From: Robby Zambito <contact@robbyzambito.me>
Date: Sun, 1 Feb 2026 14:29:53 -0500
Subject: Update to Saprus 0.2.1

Handle management messages instead of letting them bubble up through the
connection to the consumer.
Right now, this just means handling ping messages by sending a pong.

Also updated to follow the new handshake flow.
The sentinel will mirror the ports instead of matching them.

Now filters on the full source and dest ports, which are less likely to
have erroneous matches.
---
 src/RawSocket.zig | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

(limited to 'src/RawSocket.zig')

diff --git a/src/RawSocket.zig b/src/RawSocket.zig
index 5732ce9..e43a8e4 100644
--- a/src/RawSocket.zig
+++ b/src/RawSocket.zig
@@ -133,7 +133,7 @@ pub fn receive(self: RawSocket, buf: []u8) ![]u8 {
     return buf[0..len];
 }
 
-pub fn attachSaprusPortFilter(self: RawSocket, port: u16) !void {
+pub fn attachSaprusPortFilter(self: RawSocket, incoming_src_port: ?u16, incoming_dest_port: u16) !void {
     const BPF = std.os.linux.BPF;
     // BPF instruction structure for classic BPF
     const SockFilter = extern struct {
@@ -149,11 +149,26 @@ pub fn attachSaprusPortFilter(self: RawSocket, port: u16) !void {
     };
 
     // Build the filter program
-    const filter = [_]SockFilter{
+    const filter = if (incoming_src_port) |inc_src| &[_]SockFilter{
         // Load 2 bytes at offset 46 (absolute)
         .{ .code = BPF.LD | BPF.H | BPF.ABS, .jt = 0, .jf = 0, .k = 46 },
+        // Jump if equal to port (skip 1 if true, skip 0 if false)
+        .{ .code = BPF.JMP | BPF.JEQ | BPF.K, .jt = 1, .jf = 0, .k = @as(u32, inc_src) },
+        // Return 0x0 (fail)
+        .{ .code = BPF.RET | BPF.K, .jt = 0, .jf = 0, .k = 0x0 },
+        // Load 2 bytes at offset 48 (absolute)
+        .{ .code = BPF.LD | BPF.H | BPF.ABS, .jt = 0, .jf = 0, .k = 48 },
+        // Jump if equal to port (skip 0 if true, skip 1 if false)
+        .{ .code = BPF.JMP | BPF.JEQ | BPF.K, .jt = 0, .jf = 1, .k = @as(u32, incoming_dest_port) },
+        // Return 0xffff (pass)
+        .{ .code = BPF.RET | BPF.K, .jt = 0, .jf = 0, .k = 0xffff },
+        // Return 0x0 (fail)
+        .{ .code = BPF.RET | BPF.K, .jt = 0, .jf = 0, .k = 0x0 },
+    } else &[_]SockFilter{
+        // Load 2 bytes at offset 48 (absolute)
+        .{ .code = BPF.LD | BPF.H | BPF.ABS, .jt = 0, .jf = 0, .k = 48 },
         // Jump if equal to port (skip 0 if true, skip 1 if false)
-        .{ .code = BPF.JMP | BPF.JEQ | BPF.K, .jt = 0, .jf = 1, .k = @as(u32, port) },
+        .{ .code = BPF.JMP | BPF.JEQ | BPF.K, .jt = 0, .jf = 1, .k = @as(u32, incoming_dest_port) },
         // Return 0xffff (pass)
         .{ .code = BPF.RET | BPF.K, .jt = 0, .jf = 0, .k = 0xffff },
         // Return 0x0 (fail)
@@ -161,8 +176,8 @@ pub fn attachSaprusPortFilter(self: RawSocket, port: u16) !void {
     };
 
     const fprog = SockFprog{
-        .len = filter.len,
-        .filter = &filter,
+        .len = @intCast(filter.len),
+        .filter = filter.ptr,
     };
 
     // Attach filter to socket using setsockopt
-- 
cgit 


From 2c9e648c2c9c487c0239760bff23a70c059f018f Mon Sep 17 00:00:00 2001
From: Robby Zambito <contact@robbyzambito.me>
Date: Sun, 1 Feb 2026 19:35:14 -0500
Subject: Clean API and add docs

---
 src/RawSocket.zig | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

(limited to 'src/RawSocket.zig')

diff --git a/src/RawSocket.zig b/src/RawSocket.zig
index e43a8e4..9561dcf 100644
--- a/src/RawSocket.zig
+++ b/src/RawSocket.zig
@@ -32,7 +32,12 @@ const Ifconf = extern struct {
     },
 };
 
-pub fn init() !RawSocket {
+pub fn init() error{
+    SocketError,
+    NicError,
+    NoInterfaceFound,
+    BindError,
+}!RawSocket {
     const socket: i32 = std.math.cast(i32, std.os.linux.socket(std.os.linux.AF.PACKET, std.os.linux.SOCK.RAW, 0)) orelse return error.SocketError;
     if (socket < 0) return error.SocketError;
 
-- 
cgit