tiny.reticulum.packet.filter

1const std = @import("std");2const wire = @import("../wire/root.zig");34pub const Verdict = enum(u1) {5    reject,6    admit,7};89fn contextPassthrough(context: wire.Context) bool {10    return switch (context) {11        .keepalive,12        .resource_req,13        .resource_prf,14        .resource,15        .cache_request,16        .channel,17        => true,18        else => false,19    };20}2122/// Decides whether a node acts on an arriving packet, for a caller that runs23/// every arriving packet past this check before doing anything with it. The24/// call rejects a packet of any type but an announce that carries a transport25/// id, unless that id is this node's own. The call admits a packet whatever26/// else holds for six context bytes: keepalive, resource, resource request,27/// resource proof, cache request, and channel, because a link or a resource28/// transfer repeats them. The check rejects a packet addressed to a plain or29/// group destination when it is an announce or its hop count exceeds one, and30/// admits it otherwise. The call rejects a packet whose packet hash the node31/// has already seen, and admits an announce to a single destination again so a32/// fresher path can be taken. Reticulum 1.5.0 filters against its shared33/// instance before reaching these rules, and this call leaves that to the34/// caller, following Reticulum@1.5.0 RNS/Transport.py:1571-1628.35pub fn admit(36    value: *const wire.Packet,37    seen: bool,38    own_transport_hash: ?[16]u8,39) Verdict {40    if (value.transport_id) |transport_id| {41        if (value.packet_type != .announce) {42            const own = own_transport_hash orelse return .reject;43            if (!std.mem.eql(u8, &transport_id, &own)) return .reject;44        }45    }46    if (contextPassthrough(value.context)) return .admit;47    switch (value.destination_type) {48        .plain, .group => {49            if (value.packet_type == .announce) return .reject;50            if (value.hops > 1) return .reject;51            return .admit;52        },53        else => {},54    }55    if (!seen) return .admit;56    if (value.packet_type == .announce and value.destination_type == .single) {57        return .admit;58    }59    return .reject;60}6162fn packet() wire.Packet {63    return .{64        .ifac = 0,65        .header = .one,66        .context_flag = 0,67        .transport = .broadcast,68        .destination_type = .single,69        .packet_type = .data,70        .hops = 0,71        .transport_id = null,72        .destination = @splat(0),73        .context = .none,74        .payload = &.{},75    };76}7778test "Reticulum@1.5.0 RNS/Transport.py:1576-1580 rejects another transport" {79    var value = packet();80    value.header = .two;81    value.transport_id = @splat(1);82    try @import("std").testing.expectEqual(Verdict.reject, admit(&value, false, @splat(2)));83}8485test "Reticulum@1.5.0 RNS/Transport.py:1576-1580 admits its transport" {86    var value = packet();87    value.header = .two;88    value.transport_id = @splat(1);89    try @import("std").testing.expectEqual(Verdict.admit, admit(&value, false, @splat(1)));90}9192test "Reticulum@1.5.0 RNS/Transport.py:1577 lets announces cross transports" {93    var value = packet();94    value.header = .two;95    value.transport_id = @splat(1);96    value.packet_type = .announce;97    try @import("std").testing.expectEqual(Verdict.admit, admit(&value, false, @splat(2)));98}99100fn expectContext(context: wire.Context) !void {101    var value = packet();102    value.context = context;103    try std.testing.expectEqual(Verdict.admit, admit(&value, true, null));104}105106test "Reticulum@1.5.0 RNS/Transport.py:1582 passes keepalive context" {107    try expectContext(.keepalive);108}109110test "Reticulum@1.5.0 RNS/Transport.py:1583 passes resource request context" {111    try expectContext(.resource_req);112}113114test "Reticulum@1.5.0 RNS/Transport.py:1584 passes resource proof context" {115    try expectContext(.resource_prf);116}117118test "Reticulum@1.5.0 RNS/Transport.py:1585 passes resource context" {119    try expectContext(.resource);120}121122test "Reticulum@1.5.0 RNS/Transport.py:1586 passes cache request context" {123    try expectContext(.cache_request);124}125126test "Reticulum@1.5.0 RNS/Transport.py:1587 passes channel context" {127    try expectContext(.channel);128}129130test "Reticulum@1.5.0 RNS/Transport.py:1589-1596 admits local plain data" {131    var value = packet();132    value.destination_type = .plain;133    value.hops = 1;134    try std.testing.expectEqual(Verdict.admit, admit(&value, true, null));135}136137test "Reticulum@1.5.0 RNS/Transport.py:1591-1594 rejects transported plain data" {138    var value = packet();139    value.destination_type = .plain;140    value.hops = 2;141    try std.testing.expectEqual(Verdict.reject, admit(&value, false, null));142}143144test "Reticulum@1.5.0 RNS/Transport.py:1597-1600 rejects plain announces" {145    var value = packet();146    value.destination_type = .plain;147    value.packet_type = .announce;148    try std.testing.expectEqual(Verdict.reject, admit(&value, false, null));149}150151test "Reticulum@1.5.0 RNS/Transport.py:1602-1609 admits local group data" {152    var value = packet();153    value.destination_type = .group;154    value.hops = 1;155    try std.testing.expectEqual(Verdict.admit, admit(&value, true, null));156}157158test "Reticulum@1.5.0 RNS/Transport.py:1604-1607 rejects transported group data" {159    var value = packet();160    value.destination_type = .group;161    value.hops = 2;162    try std.testing.expectEqual(Verdict.reject, admit(&value, false, null));163}164165test "Reticulum@1.5.0 RNS/Transport.py:1610-1613 rejects group announces" {166    var value = packet();167    value.destination_type = .group;168    value.packet_type = .announce;169    try std.testing.expectEqual(Verdict.reject, admit(&value, false, null));170}171172test "Reticulum@1.5.0 RNS/Transport.py:1615 admits unseen packets" {173    try @import("std").testing.expectEqual(Verdict.admit, admit(&packet(), false, null));174}175176test "Reticulum@1.5.0 RNS/Transport.py:1617-1619 readmits single announces" {177    var value = packet();178    value.packet_type = .announce;179    try std.testing.expectEqual(Verdict.admit, admit(&value, true, null));180}181182test "Reticulum@1.5.0 RNS/Transport.py:1617-1623 rejects other duplicate announces" {183    var value = packet();184    value.packet_type = .announce;185    value.destination_type = .link;186    try std.testing.expectEqual(Verdict.reject, admit(&value, true, null));187}188189test "Reticulum@1.5.0 RNS/Transport.py:1625-1626 rejects other duplicates" {190    try @import("std").testing.expectEqual(Verdict.reject, admit(&packet(), true, null));191}

1pub const filter = @import("filter.zig");