From e2f0151054af721d383a39543c7c5847c99eb5a0 Mon Sep 17 00:00:00 2001
From: Youness Alaoui <youness.alaoui@collabora.co.uk>
Date: Thu, 12 Feb 2009 18:34:03 -0500
Subject: [PATCH] stupid WLM 2009 CRC32 typo workaround (ugly, I know...)

---
 stun/stunagent.c | 9 +++++++++
 stun/stuncrc32.c | 9 +++++++--
 stun/stuncrc32.h | 1 +
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/stun/stunagent.c b/stun/stunagent.c
index faad925..7679c8d 100644
--- a/stun/stunagent.c
+++ b/stun/stunagent.c
@@ -146,6 +146,11 @@ StunValidationStatus stun_agent_validate (StunAgent *agent, StunMessage *msg,
       return STUN_VALIDATION_BAD_REQUEST;
     }
 
+    if (agent->compatibility == STUN_COMPATIBILITY_WLM2009)
+      wlm2009_stupid_crc32_typo = 1;
+    else
+      wlm2009_stupid_crc32_typo = 0;
+
     /* Checks FINGERPRINT */
     crc32 = stun_fingerprint (msg->buffer, stun_message_length (msg));
     fpr = ntohl (fpr);
@@ -575,6 +580,10 @@ size_t stun_agent_finish_message (StunAgent *agent, StunMessage *msg,
     }
 
 
+    if (agent->compatibility == STUN_COMPATIBILITY_WLM2009)
+      wlm2009_stupid_crc32_typo = 1;
+    else
+      wlm2009_stupid_crc32_typo = 0;
     fpr = stun_fingerprint (msg->buffer, stun_message_length (msg));
     memcpy (ptr, &fpr, sizeof (fpr));
 
diff --git a/stun/stuncrc32.c b/stun/stuncrc32.c
index 29289b7..0f3fa66 100644
--- a/stun/stuncrc32.c
+++ b/stun/stuncrc32.c
@@ -89,6 +89,7 @@
 
 #include "stuncrc32.h"
 
+int wlm2009_stupid_crc32_typo = 0;
 
 static const uint32_t crc32_tab[] = {
         0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
@@ -147,8 +148,12 @@ uint32_t crc32 (const crc_data *data, size_t n)
     const uint8_t *p = data[i].buf;
     size_t size = data[i].len;
 
-    while (size--)
-      crc = crc32_tab[(crc ^ *p++) & 0xFF] ^ (crc >> 8);
+    while (size--) {
+      uint32_t lkp = crc32_tab[(crc ^ *p++) & 0xFF];
+      if (lkp == 0x8bbeb8ea && wlm2009_stupid_crc32_typo)
+        lkp = 0x8bbe8ea;
+      crc =  lkp ^ (crc >> 8);
+    }
   }
 
   return crc ^ 0xffffffff;
diff --git a/stun/stuncrc32.h b/stun/stuncrc32.h
index 2aeb579..0ebd2c2 100644
--- a/stun/stuncrc32.h
+++ b/stun/stuncrc32.h
@@ -53,6 +53,7 @@ typedef struct {
 } crc_data;
 
 
+int wlm2009_stupid_crc32_typo;
 uint32_t crc32 (const crc_data *data, size_t n);
 
 #endif /* _CRC32_H */
-- 
2.11.4.GIT