From ad4cec0b0780fb3d3d6e4fad3280e937162f01fa Mon Sep 17 00:00:00 2001
From: Gregor Richards <hg-yff@gregor.im>
Date: Wed, 28 Sep 2016 08:04:38 -0400
Subject: [PATCH] Make netplay lenient to differing sram sizes

Some cores can only determine the true size of sram after fully loading
the content, and so will report different values when the sram size is
queried. As a result, netplay cannot count on sram size as a reliable
verification technique. sram is still sent for the savestateless core
case.
---
 network/netplay/netplay_common.c | 57 +++++++++++++++++++++++---------
 1 file changed, 41 insertions(+), 16 deletions(-)

diff --git a/network/netplay/netplay_common.c b/network/netplay/netplay_common.c
index c55174a398..03c01afd21 100644
--- a/network/netplay/netplay_common.c
+++ b/network/netplay/netplay_common.c
@@ -127,7 +127,7 @@ uint32_t netplay_impl_magic(void)
 
 bool netplay_send_info(netplay_t *netplay)
 {
-   unsigned sram_size;
+   unsigned sram_size, remote_sram_size;
    retro_ctx_memory_info_t mem_info;
    char msg[512]             = {0};
    uint32_t *content_crc_ptr = NULL;
@@ -167,10 +167,13 @@ bool netplay_send_info(netplay_t *netplay)
       return false;
    }
 
-   if (mem_info.size != ntohl(header[2]))
+   /* Some cores only report the correct sram size late, so we can't actually
+    * error out if the sram size seems wrong. */
+   sram_size = mem_info.size;
+   remote_sram_size = ntohl(header[2]);
+   if (sram_size != 0 && remote_sram_size != 0 && sram_size != remote_sram_size)
    {
-      RARCH_ERR("Content SRAM sizes do not correspond.\n");
-      return false;
+      RARCH_WARN("Content SRAM sizes do not correspond.\n");
    }
 
    if (!netplay_send_nickname(netplay, netplay->fd))
@@ -181,14 +184,36 @@ bool netplay_send_info(netplay_t *netplay)
    }
 
    /* Get SRAM data from User 1. */
-   sram      = mem_info.data;
-   sram_size = mem_info.size;
-
-   if (!socket_receive_all_blocking(netplay->fd, sram, sram_size))
+   if (sram_size != 0 && sram_size == remote_sram_size)
    {
-      RARCH_ERR("%s\n",
-            msg_hash_to_str(MSG_FAILED_TO_RECEIVE_SRAM_DATA_FROM_HOST));
-      return false;
+      sram      = mem_info.data;
+
+      if (!socket_receive_all_blocking(netplay->fd, sram, sram_size))
+      {
+         RARCH_ERR("%s\n",
+               msg_hash_to_str(MSG_FAILED_TO_RECEIVE_SRAM_DATA_FROM_HOST));
+         return false;
+      }
+
+   }
+   else if (remote_sram_size != 0)
+   {
+      /* We can't load this, but we still need to get rid of the data */
+      uint32_t quickbuf;
+      while (remote_sram_size > 0)
+      {
+         if (!socket_receive_all_blocking(netplay->fd, &quickbuf, (remote_sram_size > sizeof(uint32_t)) ? sizeof(uint32_t) : remote_sram_size))
+         {
+            RARCH_ERR("%s\n",
+                  msg_hash_to_str(MSG_FAILED_TO_RECEIVE_SRAM_DATA_FROM_HOST));
+            return false;
+         }
+         if (remote_sram_size > sizeof(uint32_t))
+            remote_sram_size -= sizeof(uint32_t);
+         else
+            remote_sram_size = 0;
+      }
+
    }
 
    if (!netplay_get_nickname(netplay, netplay->fd))
@@ -225,7 +250,7 @@ bool netplay_send_info(netplay_t *netplay)
 
 bool netplay_get_info(netplay_t *netplay)
 {
-   unsigned sram_size;
+   unsigned sram_size, remote_sram_size;
    uint32_t header[3];
    retro_ctx_memory_info_t mem_info;
    uint32_t *content_crc_ptr = NULL;
@@ -267,10 +292,11 @@ bool netplay_get_info(netplay_t *netplay)
       return false;
    }
 
-   if (mem_info.size != ntohl(header[2]))
+   sram_size = mem_info.size;
+   remote_sram_size = ntohl(header[2]);
+   if (sram_size != 0 && remote_sram_size != 0 && sram_size != remote_sram_size)
    {
-      RARCH_ERR("Content SRAM sizes do not correspond.\n");
-      return false;
+      RARCH_WARN("Content SRAM sizes do not correspond.\n");
    }
 
    if (!netplay_get_nickname(netplay, netplay->fd))
@@ -282,7 +308,6 @@ bool netplay_get_info(netplay_t *netplay)
 
    /* Send SRAM data to our User 2. */
    sram      = mem_info.data;
-   sram_size = mem_info.size;
 
    if (!socket_send_all_blocking(netplay->fd, sram, sram_size, false))
    {