Added checksums to packets

build-windows-visual-studio/sm64ex.vcxproj

@@ -71,6 +71,7 @@
   <PropertyGroup Label="UserMacros" />
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <LinkIncremental>true</LinkIncremental>
+    <IncludePath>../;../include/;../src/;$(IncludePath)</IncludePath>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
     <LinkIncremental>true</LinkIncremental>
@@ -3953,6 +3954,7 @@
     <ClCompile Include="..\src\pc\network\packets\packet_read_write.c" />
     <ClCompile Include="..\src\pc\network\packets\packet_reliable.c" />
     <ClCompile Include="..\src\pc\network\packets\packet_spawn_objects.c" />
+    <ClCompile Include="..\src\pc\network\packets\packet_spawn_star.c" />
     <ClCompile Include="..\src\pc\pc_main.c" />
     <ClCompile Include="..\src\pc\platform.c" />
     <ClCompile Include="..\src\pc\ultra_reimplementation.c" />

build-windows-visual-studio/sm64ex.vcxproj.filters

@@ -14970,6 +14970,9 @@
     <ClCompile Include="..\src\pc\network\packets\packet_spawn_objects.c">
       <Filter>Source Files\src\pc\network\packets</Filter>
     </ClCompile>
+    <ClCompile Include="..\src\pc\network\packets\packet_spawn_star.c">
+      <Filter>Source Files\src\pc\network\packets</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="..\actors\common0.h">

src/pc/network/network.c

@@ -68,7 +68,9 @@ void network_send(struct Packet* p) {
 
     network_remember_reliable(p);
 
-    int rc = sendto(gSocket, p->buffer, p->cursor, 0, (SOCKADDR *)& txAddr, sizeof(txAddr));
+    u32 hash = packet_hash(p);
+    memcpy(&p->buffer[p->dataLength], &hash, sizeof(u32));
+    int rc = sendto(gSocket, p->buffer, p->cursor + sizeof(u32), 0, (SOCKADDR *)& txAddr, sizeof(txAddr));
     if (rc == SOCKET_ERROR) {
         wprintf(L"%s sendto failed with error: %d\n", NETWORKTYPESTR, WSAGetLastError());
         return;
@@ -104,6 +106,11 @@ void network_update(void) {
         }
         if (rc == 0) { break; }
 
+        p.dataLength = rc - sizeof(u32);
+        if (!packet_check_hash(&p)) {
+            printf("Invalid packet!\n");
+        }
+
         switch (p.buffer[0]) {
             case PACKET_ACK: network_receive_ack(&p); break;
             case PACKET_PLAYER: network_receive_player(&p); break;

src/pc/network/network.h

@@ -27,6 +27,7 @@ enum PacketType {
 };
 
 struct Packet {
+    int dataLength;
     int cursor;
     bool error;
     bool reliable;
@@ -67,6 +68,8 @@ void network_shutdown(void);
 void packet_init(struct Packet* packet, enum PacketType packetType, bool reliable);
 void packet_write(struct Packet* packet, void* data, int length);
 void packet_read(struct Packet* packet, void* data, int length);
+u32 packet_hash(struct Packet* packet);
+bool packet_check_hash(struct Packet* packet);
 
 // packet headers
 void network_send_ack(struct Packet* p);

src/pc/network/packets/packet_read_write.c

@@ -10,6 +10,7 @@ void packet_init(struct Packet* packet, enum PacketType packetType, bool reliabl
         nextSeqNum++;
         if (nextSeqNum == 0) { nextSeqNum++;  }
     }
+    packet->dataLength = 3;
     packet->cursor = 3;
     packet->error = false;
     packet->reliable = reliable;
@@ -19,6 +20,7 @@ void packet_init(struct Packet* packet, enum PacketType packetType, bool reliabl
 void packet_write(struct Packet* packet, void* data, int length) {
     if (data == NULL) { packet->error = true; return; }
     memcpy(&packet->buffer[packet->cursor], data, length);
+    packet->dataLength += length;
     packet->cursor += length;
 }
 
@@ -28,3 +30,20 @@ void packet_read(struct Packet* packet, void* data, int length) {
     memcpy(data, &packet->buffer[cursor], length);
     packet->cursor = cursor + length;
 }
+
+u32 packet_hash(struct Packet* packet) {
+    u32 hash = 0;
+    int byte = 0;
+    for (int i = 0; i < packet->dataLength; i++) {
+        hash ^= ((u32)packet->buffer[i]) << (8 * byte);
+        byte = (byte + 1) % sizeof(u32);
+    }
+    return hash;
+}
+
+bool packet_check_hash(struct Packet* packet) {
+    u32 localHash = packet_hash(packet);
+    u32 packetHash = 0;
+    memcpy(&packetHash, &packet->buffer[packet->dataLength], sizeof(u32));
+    return localHash == packetHash;
+}