ref: 7e4a268dc91d1e751e1274f60849d08b1dbf417a
parent: 76178ee71572e399ede72eac8d448595e6daac63
author: Simon Howard <fraggle@soulsphere.org>
date: Sat Feb 9 15:39:32 EST 2019
net: Add reference counting scheme for addresses. This resolves a TODO with the NAT hole punching plan. As part of this, add some comments to the net_io.h header to clarify the semantics around references relating to the resolve and receive functions, and how addresses must be released.
--- a/src/d_loop.c
+++ b/src/d_loop.c
@@ -448,6 +448,7 @@
net_loop_client_module.InitClient();
addr = net_loop_client_module.ResolveAddress(NULL);
+ NET_ReferenceAddress(addr);
}
else
{@@ -484,6 +485,7 @@
{net_sdl_module.InitClient();
addr = net_sdl_module.ResolveAddress(myargv[i+1]);
+ NET_ReferenceAddress(addr);
if (addr == NULL)
{@@ -506,6 +508,7 @@
}
printf("D_InitNetGame: Connected to %s\n", NET_AddrToString(addr));+ NET_ReleaseAddress(addr);
// Wait for launch message received from server.
--- a/src/net_client.c
+++ b/src/net_client.c
@@ -290,7 +290,7 @@
{net_client_connected = false;
- NET_FreeAddress(server_addr);
+ NET_ReleaseAddress(server_addr);
// Shut down network module, etc. To do.
}
@@ -969,12 +969,9 @@
{NET_CL_ParsePacket(packet);
}
- else
- {- NET_FreeAddress(addr);
- }
NET_FreePacket(packet);
+ NET_ReleaseAddress(addr);
}
// Run the common connection code to send any packets as needed
@@ -1029,6 +1026,7 @@
int last_send_time;
server_addr = addr;
+ NET_ReferenceAddress(addr);
memcpy(net_local_wad_sha1sum, data->wad_sha1sum, sizeof(sha1_digest_t));
memcpy(net_local_deh_sha1sum, data->deh_sha1sum, sizeof(sha1_digest_t));
--- a/src/net_defs.h
+++ b/src/net_defs.h
@@ -95,6 +95,7 @@
struct _net_addr_s
{net_module_t *module;
+ int refcount;
void *handle;
};
--- a/src/net_io.c
+++ b/src/net_io.c
@@ -59,8 +59,6 @@
int i;
net_addr_t *result;
- result = NULL;
-
for (i=0; i<context->num_modules; ++i)
{result = context->modules[i]->ResolveAddress(addr);
@@ -67,11 +65,12 @@
if (result != NULL)
{- break;
+ NET_ReferenceAddress(result);
+ return result;
}
}
- return result;
+ return NULL;
}
void NET_SendPacket(net_addr_t *addr, net_packet_t *packet)
@@ -101,6 +100,7 @@
{if (context->modules[i]->RecvPacket(addr, packet))
{+ NET_ReferenceAddress(*addr);
return true;
}
}
@@ -120,9 +120,28 @@
return buf;
}
-void NET_FreeAddress(net_addr_t *addr)
+void NET_ReferenceAddress(net_addr_t *addr)
{- addr->module->FreeAddress(addr);
+ if (addr == NULL)
+ {+ return;
+ }
+ ++addr->refcount;
+ //printf("%s: +refcount=%d\n", NET_AddrToString(addr), addr->refcount);}
+void NET_ReleaseAddress(net_addr_t *addr)
+{+ if (addr == NULL)
+ {+ return;
+ }
+
+ --addr->refcount;
+ //printf("%s: -refcount=%d\n", NET_AddrToString(addr), addr->refcount);+ if (addr->refcount <= 0)
+ {+ addr->module->FreeAddress(addr);
+ }
+}
--- a/src/net_io.h
+++ b/src/net_io.h
@@ -22,14 +22,39 @@
extern net_addr_t net_broadcast_addr;
+// Create a new network context.
net_context_t *NET_NewContext(void);
+
+// Add a network module to a context.
void NET_AddModule(net_context_t *context, net_module_t *module);
+
+// Send a packet to the given address.
void NET_SendPacket(net_addr_t *addr, net_packet_t *packet);
+
+// Send a broadcast using all modules in the given context.
void NET_SendBroadcast(net_context_t *context, net_packet_t *packet);
-boolean NET_RecvPacket(net_context_t *context, net_addr_t **addr,
+
+// Check all modules in the given context and receive a packet, returning true
+// if a packet was received. The result is stored in *packet and the source is
+// stored in *addr, with an implicit reference added. The packet must be freed
+// by the caller and the reference releasd.
+boolean NET_RecvPacket(net_context_t *context, net_addr_t **addr,
net_packet_t **packet);
+
+// Return a string representation of the given address. The result points to a
+// static buffer and will become invalid with the next call.
char *NET_AddrToString(net_addr_t *addr);
-void NET_FreeAddress(net_addr_t *addr);
+
+// Add a reference to the given address.
+void NET_ReferenceAddress(net_addr_t *addr);
+
+// Release a reference to the given address. When there are no more references,
+// the address will be freed.
+void NET_ReleaseAddress(net_addr_t *addr);
+
+// Resolve a string representation of an address. If successful, a net_addr_t
+// pointer is received with an implicit reference that must be freed by the
+// caller when it is no longer needed.
net_addr_t *NET_ResolveAddress(net_context_t *context, const char *address);
#endif /* #ifndef NET_IO_H */
--- a/src/net_query.c
+++ b/src/net_query.c
@@ -205,11 +205,25 @@
target->printed = false;
target->query_attempts = 0;
target->addr = addr;
+ NET_ReferenceAddress(addr);
++num_targets;
return target;
}
+static void FreeTargets(void)
+{+ int i;
+
+ for (i = 0; i < num_targets; ++i)
+ {+ NET_ReleaseAddress(targets[i].addr);
+ }
+ free(targets);
+ targets = NULL;
+ num_targets = 0;
+}
+
// Transmit a query packet
static void NET_Query_SendQuery(net_addr_t *addr)
@@ -333,10 +347,10 @@
// there.
addr = NET_ResolveAddress(query_context, addr_str);
-
if (addr != NULL)
{GetTargetForAddr(addr, true);
+ NET_ReleaseAddress(addr);
}
}
@@ -375,6 +389,7 @@
if (NET_RecvPacket(query_context, &addr, &packet))
{NET_Query_ParsePacket(addr, packet, callback, user_data);
+ NET_ReleaseAddress(addr);
NET_FreePacket(packet);
}
}
@@ -631,6 +646,7 @@
target = GetTargetForAddr(master, true);
target->type = QUERY_TARGET_MASTER;
+ NET_ReleaseAddress(master);
return 1;
}
@@ -746,6 +762,7 @@
NET_Query_QueryLoop(NET_QueryPrintCallback, NULL);
printf("\n%i server(s) found.\n", GetNumResponses());+ FreeTargets();
}
}
@@ -758,6 +775,7 @@
NET_Query_QueryLoop(NET_QueryPrintCallback, NULL);
printf("\n%i server(s) found.\n", GetNumResponses());+ FreeTargets();
}
}
@@ -790,6 +808,8 @@
if (target->state == QUERY_TARGET_RESPONDED)
{NET_QueryPrintCallback(addr, &target->data, target->ping_time, NULL);
+ NET_ReleaseAddress(addr);
+ FreeTargets();
}
else
{@@ -801,6 +821,7 @@
{query_target_t *target;
query_target_t *responder;
+ net_addr_t *result;
NET_Query_Init();
@@ -817,12 +838,16 @@
if (responder != NULL)
{- return responder->addr;
+ result = responder->addr;
+ NET_ReferenceAddress(result);
}
else
{- return NULL;
+ result = NULL;
}
+
+ FreeTargets();
+ return result;
}
// Block until a packet of the given type is received from the given
@@ -845,6 +870,9 @@
I_Sleep(20);
continue;
}
+
+ // Caller doesn't need additional reference.
+ NET_ReleaseAddress(packet_src);
if (packet_src == addr
&& NET_ReadInt16(packet, &read_packet_type)
--- a/src/net_sdl.c
+++ b/src/net_sdl.c
@@ -127,6 +127,7 @@
new_entry = Z_Malloc(sizeof(addrpair_t), PU_STATIC, 0);
new_entry->sdl_addr = *addr;
+ new_entry->net_addr.refcount = 0;
new_entry->net_addr.handle = &new_entry->sdl_addr;
new_entry->net_addr.module = &net_sdl_module;
--- a/src/net_server.c
+++ b/src/net_server.c
@@ -565,6 +565,7 @@
client->connect_time = I_GetTimeMS();
NET_Conn_InitServer(&client->connection, addr, protocol);
client->addr = addr;
+ NET_ReferenceAddress(addr);
client->last_send_time = -1;
// init the ticcmd send queue
@@ -1447,10 +1448,7 @@
NET_WriteInt16(sendpacket, NET_PACKET_TYPE_NAT_HOLE_PUNCH);
NET_SendPacket(addr, sendpacket);
NET_FreePacket(sendpacket);
-
- // TODO: We should NET_FreeAddress(addr) here, but this could cause a
- // problem if the client has already connected. The address system needs
- // to be changed to use a reference-counting system to prevent this.
+ NET_ReleaseAddress(addr);
}
static void NET_SV_MasterPacket(net_packet_t *packet)
@@ -1555,14 +1553,6 @@
break;
}
}
-
- // If this address is not in the list of clients, be sure to
- // free it back.
-
- if (NET_SV_FindClient(addr) == NULL)
- {- NET_FreeAddress(addr);
- }
}
@@ -1807,7 +1797,7 @@
}
free(client->name);
- NET_FreeAddress(client->addr);
+ NET_ReleaseAddress(client->addr);
// Are there any clients left connected? If not, return the
// server to the waiting-for-players state.
@@ -1895,15 +1885,9 @@
net_addr_t *new_addr;
new_addr = NET_Query_ResolveMaster(server_context);
+ NET_ReleaseAddress(master_server);
+ master_server = new_addr;
- // Has the master server changed address?
-
- if (new_addr != NULL && new_addr != master_server)
- {- NET_FreeAddress(master_server);
- master_server = new_addr;
- }
-
master_resolve_time = now;
}
@@ -1962,6 +1946,7 @@
{NET_SV_Packet(packet, addr);
NET_FreePacket(packet);
+ NET_ReleaseAddress(addr);
}
if (master_server != NULL)