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clean up and document p1xbraten detection
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@sauerbraten
sauerbraten committed Jul 10, 2021
1 parent fbf6739 commit 64a4898
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8 changes: 8 additions & 0 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@ This repository contains the source for my client mod, as well as the patches ap
- [gamehud.patch](#gamehudpatch)
- [chat_highlight_words.patch](#chat_highlight_wordspatch)
- [server_ogzs.patch](#server_ogzspatch)
- [extrapings.patch](#extrapingspatch)
- [Installation](#installation)
- [Windows](#windows)
- [macOS](#macos)
Expand Down Expand Up @@ -193,6 +194,13 @@ Improves logging when running a dedicated server:

- allows using slim .ogz files (see https://github.com/sauerbraten/genserverogz) on the server without getting `checkmaps` errors

### [extrapings.patch](./patches/extrapings.patch)

- adds the `getpbconfidence <cn>` command: returns a number between 0 and 1000, where 1000 means the player is almost certainly running p1xbraten, and 0 means the player is almost certainly not running p1xbraten (the confidence starts at 0 for all clients and increases the longer you are connected; usually 1000 is reached in less than one minute)
- adds the `enablep1xbratendetection` variable: set to 0 to disable broadcasting that you use p1xbraten (and detecting other p1xbraten players yourself)

This lets you detect other p1xbraten users connected to the same server as you. It relies on p1xbraten clients sending additional packets to the server, which the server then broadcasts to all other clients. This means you receive this information about other players, and it also means the other players can tell you're using p1xbraten. No information other than "I use p1xbraten" is sent. The information is not sent to me (p1x) or any third party, just the server you're playing on and the other players on it. Opt out if you are firefly!

## Installation

The latest builds are always at https://github.com/sauerbraten/p1xbraten/releases/latest.
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64 changes: 28 additions & 36 deletions patches/extrapings.patch
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Original file line number Diff line number Diff line change
@@ -1,16 +1,17 @@
Index: src/fpsgame/client.cpp
===================================================================
--- src/fpsgame/client.cpp (revision 6488)
--- src/fpsgame/client.cpp (revision 6502)
+++ src/fpsgame/client.cpp (working copy)
@@ -118,6 +118,7 @@
@@ -118,6 +118,8 @@

bool senditemstoserver = false, sendcrc = false; // after a map change, since server doesn't have map data
int lastping = 0;
+ int lastextraping = 0;
+ VARP(enablep1xbratendetection, 0, 1, 1);

bool connected = false, remote = false, demoplayback = false, gamepaused = false;
int sessionid = 0, mastermode = MM_OPEN, gamespeed = 100;
@@ -347,6 +348,8 @@
@@ -347,6 +349,8 @@
}
ICOMMAND(isai, "ii", (int *cn, int *type), intret(isai(*cn, *type) ? 1 : 0));

Expand All @@ -19,55 +20,46 @@ Index: src/fpsgame/client.cpp
int parseplayer(const char *arg)
{
char *end;
@@ -1046,7 +1049,14 @@
@@ -1046,7 +1050,15 @@
putint(p, N_PING);
putint(p, totalmillis);
lastping = totalmillis;
+ lastextraping = totalmillis;
}
+ else if(totalmillis-lastextraping>99) // send two extra N_PING packets between each normal one
+ else if(totalmillis-lastextraping>99) // send two extra N_CLIENTPING packets between each normal one
+ {
+ putint(p, N_PING);
+ putint(p, (totalmillis-lastping)/99); // 1, 2, 1, 2, ...
+ putint(p, N_CLIENTPING);
+ int delta = ((totalmillis-lastping)/99)%2 ? -1 : 2;
+ putint(p, player1->ping+delta); // others will see 3 N_CLIENTPINGs from us within 250ms: ping (0ms), ping-1 (99ms), ping+2 (198ms)
+ lastextraping = totalmillis;
+ }
sendclientpacket(p.finalize(), 1);
}

@@ -1757,14 +1767,36 @@
}

case N_PONG:
- addmsg(N_CLIENTPING, "i", player1->ping = (player1->ping*5+totalmillis-getint(p))/6);
+ {
+ int pong = getint(p);
+ if(pong<3) // extra N_PING response
+ {
+ int sign = pong%2 ? -1 : 1;
+ addmsg(N_CLIENTPING, "i", player1->ping+(sign*pong));
+ }
+ else addmsg(N_CLIENTPING, "i", player1->ping = (player1->ping*5+totalmillis-pong)/6);
@@ -1760,10 +1772,28 @@
addmsg(N_CLIENTPING, "i", player1->ping = (player1->ping*5+totalmillis-getint(p))/6);
break;
-
+ }
case N_CLIENTPING:
+ {
if(!d) return;
- d->ping = getint(p);
+ int ping = getint(p);
+ d->extrapings++;
+ int sign = (d->extrapings)%2 ? -1 : 1;
+ if(ping==d->ping+sign*(d->extrapings))
+ {
+ d->p1xbratenconfidence += d->extrapings * 2;
+ d->p1xbratenconfidence = min(d->p1xbratenconfidence, 1000);
+ }
+ if(!enablep1xbratendetection) d->ping = getint(p);
+ else
+ {
+ d->ping = ping;
+ d->p1xbratenconfidence -= d->extrapings;
+ d->p1xbratenconfidence = max(d->p1xbratenconfidence, -1000);
+ d->extrapings = 0;
+ int ping = getint(p);
+ int expecteddelta = (d->extrapings+1)%3 ? ((d->extrapings+1)%2 ? -1 : 2) : 0; // 0, -1, 2, 0 -1, 2, ...
+ if(expecteddelta && ping==d->ping+expecteddelta)
+ {
+ d->extrapings++;
+ d->p1xbratenconfidence += d->extrapings * 2;
+ d->p1xbratenconfidence = min(d->p1xbratenconfidence, 1000);
+ }
+ else
+ {
+ d->ping = ping;
+ if(expecteddelta) d->p1xbratenconfidence = max(d->p1xbratenconfidence-2, 0);
+ d->extrapings = 0;
+ }
+ }
break;
-
Expand All @@ -77,9 +69,9 @@ Index: src/fpsgame/client.cpp
break;
Index: src/fpsgame/game.h
===================================================================
--- src/fpsgame/game.h (revision 6488)
--- src/fpsgame/game.h (revision 6502)
+++ src/fpsgame/game.h (working copy)
@@ -565,9 +565,10 @@
@@ -557,9 +557,10 @@
int playermodel;
ai::aiinfo *ai;
int ownernum, lastnode;
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46 changes: 22 additions & 24 deletions src/fpsgame/client.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -120,6 +120,7 @@ namespace game
bool senditemstoserver = false, sendcrc = false; // after a map change, since server doesn't have map data
int lastping = 0;
int lastextraping = 0;
VARP(enablep1xbratendetection, 0, 1, 1);

bool connected = false, remote = false, demoplayback = false, gamepaused = false;
int sessionid = 0, mastermode = MM_OPEN, gamespeed = 100;
Expand Down Expand Up @@ -1105,10 +1106,11 @@ namespace game
lastping = totalmillis;
lastextraping = totalmillis;
}
else if(totalmillis-lastextraping>99) // send two extra N_PING packets between each normal one
else if(totalmillis-lastextraping>99) // send two extra N_CLIENTPING packets between each normal one
{
putint(p, N_PING);
putint(p, (totalmillis-lastping)/99); // 1, 2, 1, 2, ...
putint(p, N_CLIENTPING);
int delta = ((totalmillis-lastping)/99)%2 ? -1 : 2;
putint(p, player1->ping+delta); // others will see 3 N_CLIENTPINGs from us within 250ms: ping (0ms), ping-1 (99ms), ping+2 (198ms)
lastextraping = totalmillis;
}
sendclientpacket(p.finalize(), 1);
Expand Down Expand Up @@ -1825,33 +1827,29 @@ namespace game
}

case N_PONG:
{
int pong = getint(p);
if(pong<3) // extra N_PING response
{
int sign = pong%2 ? -1 : 1;
addmsg(N_CLIENTPING, "i", player1->ping+(sign*pong));
}
else addmsg(N_CLIENTPING, "i", player1->ping = (player1->ping*5+totalmillis-pong)/6);
addmsg(N_CLIENTPING, "i", player1->ping = (player1->ping*5+totalmillis-getint(p))/6);
break;
}

case N_CLIENTPING:
{
if(!d) return;
int ping = getint(p);
d->extrapings++;
int sign = (d->extrapings)%2 ? -1 : 1;
if(ping==d->ping+sign*(d->extrapings))
{
d->p1xbratenconfidence += d->extrapings * 2;
d->p1xbratenconfidence = min(d->p1xbratenconfidence, 1000);
}
if(!enablep1xbratendetection) d->ping = getint(p);
else
{
d->ping = ping;
d->p1xbratenconfidence -= d->extrapings;
d->p1xbratenconfidence = max(d->p1xbratenconfidence, -1000);
d->extrapings = 0;
int ping = getint(p);
int expecteddelta = (d->extrapings+1)%3 ? ((d->extrapings+1)%2 ? -1 : 2) : 0; // 0, -1, 2, 0 -1, 2, ...
if(expecteddelta && ping==d->ping+expecteddelta)
{
d->extrapings++;
d->p1xbratenconfidence += d->extrapings * 2;
d->p1xbratenconfidence = min(d->p1xbratenconfidence, 1000);
}
else
{
d->ping = ping;
if(expecteddelta) d->p1xbratenconfidence = max(d->p1xbratenconfidence-2, 0);
d->extrapings = 0;
}
}
break;
}
Expand Down

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