Changeset 1003 for pjproject

Timestamp:

Feb 26, 2007 10:31:06 PM (18 years ago)

Author:

bennylp

Message:

Finishing up STUN server side authentication

Location:

pjproject/trunk/pjlib-util

Files:

• build/pjlib_util_test.dsp (modified) (3 diffs)
• build/pjlib_util_test.vcproj (modified) (1 diff)
• include/pjlib-util/config.h (modified) (1 diff)
• include/pjlib-util/crc32.h (modified) (1 diff)
• include/pjlib-util/stun_msg.h (modified) (3 diffs)
• src/pjlib-util-test/encryption.c (modified) (3 diffs)
• src/pjlib-util-test/stun.c (added)
• src/pjlib-util-test/test.c (modified) (1 diff)
• src/pjlib-util-test/test.h (modified) (1 diff)
• src/pjlib-util/crc32.c (modified) (4 diffs)
• src/pjlib-util/stun_msg.c (modified) (11 diffs)

pjproject/trunk/pjlib-util/build/pjlib_util_test.dsp

@@ -43 +43 @@
 # PROP Target_Dir ""
 # ADD BASE CPP /nologo /W3 /GX /O2 /D "WIN32" /D "NDEBUG" /D "_CONSOLE" /D "_MBCS" /YX /FD /c
-# ADD CPP /nologo /MD /W3 /GX /O2 /I "../include" /I "../../pjlib/include" /D "NDEBUG" /D "WIN32" /D "_CONSOLE" /D "_MBCS" /D PJ_WIN32=1 /D PJ_M_I386=1 /FR /YX /FD /c
+# ADD CPP /nologo /MD /W4 /GX /O2 /I "../include" /I "../../pjlib/include" /D "NDEBUG" /D "WIN32" /D "_CONSOLE" /D "_MBCS" /D PJ_WIN32=1 /D PJ_M_I386=1 /FR /YX /FD /c
 # ADD BASE RSC /l 0x409 /d "NDEBUG"
 # ADD RSC /l 0x409 /d "NDEBUG"
@@ -67 +67 @@
 # PROP Target_Dir ""
 # ADD BASE CPP /nologo /W3 /Gm /GX /ZI /Od /D "WIN32" /D "_DEBUG" /D "_CONSOLE" /D "_MBCS" /YX /FD /GZ /c
-# ADD CPP /nologo /MTd /W3 /Gm /GX /ZI /Od /I "../include" /I "../../pjlib/include" /D "_DEBUG" /D "WIN32" /D "_CONSOLE" /D "_MBCS" /D PJ_WIN32=1 /D PJ_M_I386=1 /FR /YX /FD /GZ /c
+# ADD CPP /nologo /MTd /W4 /Gm /GX /ZI /Od /I "../include" /I "../../pjlib/include" /D "_DEBUG" /D "WIN32" /D "_CONSOLE" /D "_MBCS" /D PJ_WIN32=1 /D PJ_M_I386=1 /FR /YX /FD /GZ /c
 # ADD BASE RSC /l 0x409 /d "_DEBUG"
 # ADD RSC /l 0x409 /d "_DEBUG"
@@ -96 +96 @@
 # Begin Source File
 
+SOURCE="..\src\pjlib-util-test\stun.c"
+# End Source File
+# Begin Source File
+
 SOURCE="..\src\pjlib-util-test\test.c"
 # End Source File

pjproject/trunk/pjlib-util/build/pjlib_util_test.vcproj

@@ -234 +234 @@
                         </File>
                         <File
+                                RelativePath="..\src\pjlib-util-test\stun.c"
+                                >
+                        </File>
+                        <File
                                 RelativePath="..\src\pjlib-util-test\test.c"
                                 >

pjproject/trunk/pjlib-util/include/pjlib-util/config.h

@@ -212 +212 @@
 #endif
 
+
+/* **************************************************************************
+ * ENCRYPTION
+ */
+
+/**
+ * Specifies whether CRC32 algorithm should use the table based lookup table
+ * for faster calculation, at the expense of about 1KB table size on the
+ * executable. If zero, the CRC32 will use non-table based which is more than
+ * an order of magnitude slower.
+ *
+ * Default: 1
+ */
+#ifndef PJ_CRC32_HAS_TABLES
+#   define PJ_CRC32_HAS_TABLES                      1
+#endif
+
+
 /**
  * @}

pjproject/trunk/pjlib-util/include/pjlib-util/crc32.h

@@ -25 +25 @@
  */
 
-#include <pj/types.h>
+#include <pjlib-util/types.h>
 
 PJ_BEGIN_DECL

pjproject/trunk/pjlib-util/include/pjlib-util/stun_msg.h

@@ -1246 +1246 @@
                                         pj_stun_msg **p_response);
 
+typedef enum pj_stun_auth_policy_type
+{
+    PJ_STUN_POLICY_NONE,
+    PJ_STUN_POLICY_STATIC_SHORT_TERM,
+    PJ_STUN_POLICY_STATIC_LONG_TERM,
+    PJ_STUN_POLICY_DYNAMIC
+} pj_stun_auth_policy_type;
+
+typedef struct pj_stun_auth_policy
+{
+    pj_stun_auth_policy_type    type;
+    void                       *user_data;
+
+    union 
+    {
+        struct
+        {
+            pj_str_t      username;
+            pj_str_t      password;
+            pj_str_t      nonce;
+        } static_short_term;
+
+        struct
+        {
+            pj_str_t      realm;
+            pj_str_t      username;
+            pj_str_t      password;
+            pj_str_t      nonce;
+        } static_long_term;
+
+        struct
+        {
+            /**
+             * This callback is called by pj_stun_verify_credential() when
+             * server needs to challenge the request with 401 response.
+             *
+             * @param user_data The user data as specified in the policy.
+             * @param pool      Pool to allocate memory.
+             * @param realm     On return, the function should fill in with
+             *                  realm if application wants to use long term
+             *                  credential. Otherwise application should set
+             *                  empty string for the realm.
+             * @param nonce     On return, if application wants to use long
+             *                  term credential, it MUST fill in the nonce
+             *                  with some value. Otherwise  if short term 
+             *                  credential is wanted, it MAY set this value.
+             *                  If short term credential is wanted and the
+             *                  application doesn't want to include NONCE,
+             *                  then it must set this to empty string.
+             *
+             * @return          The callback should return PJ_SUCCESS, or
+             *                  otherwise response message will not be 
+             *                  created.
+             */
+            pj_status_t (*get_auth)(void *user_data,
+                                    pj_pool_t *pool,
+                                    pj_str_t *realm,
+                                    pj_str_t *nonce);
+
+            /**
+             * Get the password for the specified username. This function 
+             * is also used to check whether the username is valid.
+             *
+             * @param user_data The user data as specified in the policy.
+             * @param realm     The realm as specified in the message.
+             * @param username  The username as specified in the message.
+             * @param pool      Pool to allocate memory when necessary.
+             * @param password  On return, application should fill up this
+             *                  argument with the password.
+             *
+             * @return          The callback should return PJ_SUCCESS if
+             *                  username has been successfully verified
+             *                  and password was obtained. If non-PJ_SUCCESS
+             *                  is returned, it is assumed that the
+             *                  username is not valid.
+             */
+            pj_status_t (*get_password)(void *user_data, 
+                                        const pj_str_t *realm,
+                                        const pj_str_t *username,
+                                        pj_pool_t *pool,
+                                        pj_str_t *password);
+            pj_bool_t   (*require_nonce)(void *user_data,
+                                         const pj_str_t *realm,
+                                         const pj_str_t *username);
+            pj_bool_t   (*verify_nonce)(void *data,
+                                        const pj_str_t *realm,
+                                        const pj_str_t *username,
+                                        const pj_str_t *nonce);
+            pj_status_t (*make_nonce)(void *user_data,
+                                      const pj_str_t *realm,
+                                      const pj_str_t *username,
+                                      pj_pool_t *pool,
+                                      pj_str_t *nonce);
+        } dynamic;
+
+    } data;
+
+} pj_stun_auth_policy;
+
+
 /**
  * Verify credential in the STUN message. Note that before calling this
@@ -1253 +1353 @@
  * if it doesn't contain PJ_STUN_ATTR_MESSAGE_INTEGRITY attribute.
  *
- * @param msg           The message to be verified.
- * @param realm         Realm, if long term credential is required. If
- *                      short term credential is required, this argument
- *                      must be set to NULL.
- * @param username      If this attribute is specified, then the USERNAME
- *                      attribute in the message will be compared against
- *                      this value. If NULL is specified, then this function
- *                      will accept any usernames.
- * @param password      The password.
- * @param options       Options, must be zero for now.
+ * @param pkt           The original packet which has been parsed into
+ *                      the message. This packet MUST NOT have been modified
+ *                      after the parsing.
+ * @param pkt_len       The length of the packet.
+ * @param msg           The parsed message to be verified.
+ * @param policy        Pointer to authentication policy.
  * @param pool          If response is to be created, then memory will
  *                      be allocated from this pool.
@@ -1274 +1370 @@
  *                      \a p_response.
  */
-PJ_DECL(pj_status_t) pj_stun_verify_credential(const pj_stun_msg *msg,
-                                               const pj_str_t *realm,
-                                               const pj_str_t *username,
-                                               const pj_str_t *password,
-                                               unsigned options,
+PJ_DECL(pj_status_t) pj_stun_verify_credential(const pj_uint8_t *pkt,
+                                               unsigned pkt_len,
+                                               const pj_stun_msg *msg,
+                                               pj_stun_auth_policy *policy,
                                                pj_pool_t *pool,
                                                pj_stun_msg **p_response);

pjproject/trunk/pjlib-util/src/pjlib-util-test/encryption.c

@@ -423 +423 @@
     PJ_LOG(3, (THIS_FILE, "  crc32 test.."));
 
+    /* testing pj_crc32_calc */
     for (i=0; i<PJ_ARRAY_SIZE(crc32_test_data); ++i) {
         pj_uint32_t crc;
@@ -433 +434 @@
         }
     }
+
+    /* testing incremental CRC32 calculation */
+    for (i=0; i<PJ_ARRAY_SIZE(crc32_test_data); ++i) {
+        pj_crc32_context ctx;
+        pj_uint32_t crc0, crc1;
+        unsigned len;
+
+        len = pj_ansi_strlen(crc32_test_data[i].input);
+        crc0 = pj_crc32_calc((pj_uint8_t*)crc32_test_data[i].input, len);
+
+        pj_crc32_init(&ctx);
+        pj_crc32_update(&ctx, (pj_uint8_t*)crc32_test_data[i].input,
+                        len / 2);
+
+        if (len/2 > 0) {
+            pj_crc32_update(&ctx, (pj_uint8_t*)crc32_test_data[i].input + len/2,
+                            len - len/2);
+        }
+
+        crc1 = pj_crc32_final(&ctx);
+
+        if (crc0 != crc1) {
+            PJ_LOG(3,(THIS_FILE, 
+                      "    error: crc algorithm error on test %d", i));
+            return -85;
+        }
+
+    }
     return 0;
 }
@@ -460 +489 @@
 }
 
+static void crc32_update(pj_crc32_context *c, const pj_uint8_t *data,
+                         pj_size_t nbytes)
+{
+    pj_crc32_update(c, data, nbytes);
+}
+
+static void crc32_final(pj_crc32_context *ctx, pj_uint32_t *digest)
+{
+    *digest = pj_crc32_final(ctx);
+}
+
+int encryption_benchmark()
+{
+    pj_pool_t *pool;
+    pj_uint8_t *input;
+    union {
+        pj_md5_context md5_context;
+        pj_sha1_context sha1_context;
+    } context;
+    pj_uint8_t digest[32];
+    pj_size_t input_len;
+    struct algorithm
+    {
+        const char *name;
+        void (*init_context)(void*);
+        void (*update)(void*, const pj_uint8_t*, unsigned);
+        void (*final)(void*, void*);
+        pj_uint32_t t;
+    } algorithms[] = 
+    {
+        {
+            "MD5  ",
+            &pj_md5_init,
+            &pj_md5_update,
+            &pj_md5_final
+        },
+        {
+            "SHA1 ",
+            &pj_sha1_init,
+            &pj_sha1_update,
+            &pj_sha1_final
+        },
+        {
+            "CRC32",
+            &pj_crc32_init,
+            &crc32_update,
+            &crc32_final
+        }
+    };
+#if defined(PJ_DEBUG) && PJ_DEBUG!=0
+    enum { LOOP = 1000 };
+#else
+    enum { LOOP = 10000 };
+#endif
+    unsigned i;
+    double total_len;
+
+    input_len = 2048;
+    total_len = input_len * LOOP;
+    pool = pj_pool_create(mem, "enc", input_len+256, 0, NULL);
+    if (!pool)
+        return PJ_ENOMEM;
+
+    input = pj_pool_alloc(pool, input_len);
+    pj_memset(input, '\xaa', input_len);
+    
+    PJ_LOG(3, (THIS_FILE, "  feeding %d Mbytes of data",
+               (unsigned)(total_len/1024/1024)));
+
+    /* Dry run */
+    for (i=0; i<PJ_ARRAY_SIZE(algorithms); ++i) {
+        algorithms[i].init_context(&context);
+        algorithms[i].update(&context, input, input_len);
+        algorithms[i].final(&context, digest);
+    }
+
+    /* Run */
+    for (i=0; i<PJ_ARRAY_SIZE(algorithms); ++i) {
+        int j;
+        pj_timestamp t1, t2;
+
+        pj_get_timestamp(&t1);
+        algorithms[i].init_context(&context);
+        for (j=0; j<LOOP; ++j) {
+            algorithms[i].update(&context, input, input_len);
+        }
+        algorithms[i].final(&context, digest);
+        pj_get_timestamp(&t2);
+
+        algorithms[i].t = pj_elapsed_usec(&t1, &t2);
+    }
+
+    /* Results */
+    for (i=0; i<PJ_ARRAY_SIZE(algorithms); ++i) {
+        double bytes;
+
+        bytes = (total_len * 1000000 / algorithms[i].t);
+        PJ_LOG(3, (THIS_FILE, "    %s:%8d usec (%3d.%03d Mbytes/sec)",
+                   algorithms[i].name, algorithms[i].t,
+                   (unsigned)(bytes / 1024 / 1024),
+                   ((unsigned)(bytes) % (1024 * 1024)) / 1024));
+    }
+
+    return 0;
+}
+
 
 

pjproject/trunk/pjlib-util/src/pjlib-util-test/test.c

@@ -69 +69 @@
 #if INCLUDE_ENCRYPTION_TEST
     DO_TEST(encryption_test());
+    DO_TEST(encryption_benchmark());
 #endif
 
+#if INCLUDE_STUN_TEST
+    DO_TEST(stun_test());
+#endif
 
 on_return:

pjproject/trunk/pjlib-util/src/pjlib-util-test/test.h

@@ -21 +21 @@
 #define INCLUDE_XML_TEST            1
 #define INCLUDE_ENCRYPTION_TEST     1
+#define INCLUDE_STUN_TEST           1
 
 extern int xml_test(void);
 extern int encryption_test();
+extern int encryption_benchmark();
+extern int stun_test();
 extern int test_main(void);
 

pjproject/trunk/pjlib-util/src/pjlib-util/crc32.c

@@ -4 +4 @@
  * for a formal specification
  *
- * This file is partly taken from Crypto++ library (http://www.cryptopp.com).
+ * This file is partly taken from Crypto++ library (http://www.cryptopp.com)
+ * and http://www.di-mgt.com.au/crypto.html#CRC.
  *
  * Since the original version of the code is put in public domain,
@@ -11 +12 @@
 #include <pjlib-util/crc32.h>
 
+
+#define CRC32_NEGL  0xffffffffL
+
+#if defined(PJ_CRC32_HAS_TABLES) && PJ_CRC32_HAS_TABLES!=0
 // crc.cpp - written and placed in the public domain by Wei Dai
 
@@ -139 +144 @@
 
 
-#define CRC32_NEGL  0xffffffffL
-
-
 PJ_DEF(void) pj_crc32_init(pj_crc32_context *ctx)
 {
@@ -181 +183 @@
 }
 
+
+#else
+
+PJ_DEF(void) pj_crc32_init(pj_crc32_context *ctx)
+{
+    ctx->crc_state = CRC32_NEGL;
+}
+
+
+PJ_DEF(pj_uint32_t) pj_crc32_update(pj_crc32_context *ctx, 
+                                    const pj_uint8_t *octets,
+                                    pj_size_t len)
+
+{
+    pj_uint32_t crc = ctx->crc_state;
+    
+    while (len--) {
+        pj_uint32_t temp;
+        int j;
+
+        temp = (pj_uint32_t)((crc & 0xFF) ^ *octets++);
+        for (j = 0; j < 8; j++)
+        {
+            if (temp & 0x1)
+                temp = (temp >> 1) ^ 0xEDB88320;
+            else
+                temp >>= 1;
+        }
+        crc = (crc >> 8) ^ temp;
+    }
+    ctx->crc_state = crc;
+
+    return crc ^ CRC32_NEGL;
+}
+
+PJ_DEF(pj_uint32_t) pj_crc32_final(pj_crc32_context *ctx)
+{
+    ctx->crc_state ^= CRC32_NEGL;
+    return ctx->crc_state;
+}
+
+#endif
+
+
 PJ_DEF(pj_uint32_t) pj_crc32_calc( const pj_uint8_t *data,
                                    pj_size_t nbytes)

pjproject/trunk/pjlib-util/src/pjlib-util/stun_msg.c

@@ -22 +22 @@
 #include <pjlib-util/hmac_sha1.h>
 #include <pjlib-util/md5.h>
+#include <pjlib-util/sha1.h>
 #include <pj/assert.h>
 #include <pj/log.h>
@@ -1560 +1561 @@
     unsigned uattr_cnt;
     const pj_uint8_t *start_pdu = pdu;
+    pj_bool_t has_msg_int = PJ_FALSE;
+    pj_bool_t has_fingerprint = PJ_FALSE;
     pj_status_t status;
 
@@ -1587 +1590 @@
 
     pdu += sizeof(pj_stun_msg_hdr);
-    pdu_len -= sizeof(pj_stun_msg_hdr);
+    /* pdu_len -= sizeof(pj_stun_msg_hdr); */
+    pdu_len = msg->hdr.length;
 
     /* No need to create response if this is not a request */
@@ -1688 +1692 @@
                 return status;
             }
-            
+
+            if (attr_type == PJ_STUN_ATTR_MESSAGE_INTEGRITY && 
+                !has_fingerprint) 
+            {
+                if (has_msg_int) {
+                    /* Already has MESSAGE-INTEGRITY */
+                    if (p_response) {
+                        pj_str_t e;
+                        e = pj_str("MESSAGE-INTEGRITY already present");
+                        pj_stun_msg_create_response(pool, msg,
+                                                    PJ_STUN_STATUS_BAD_REQUEST,
+                                                    NULL, p_response);
+                    }
+                    return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_STATUS_BAD_REQUEST);
+                }
+                has_msg_int = PJ_TRUE;
+
+            } else if (attr_type == PJ_STUN_ATTR_FINGERPRINT) {
+                if (has_fingerprint) {
+                    /* Already has FINGERPRINT */
+                    if (p_response) {
+                        pj_str_t e;
+                        e = pj_str("FINGERPRINT already present");
+                        pj_stun_msg_create_response(pool, msg,
+                                                    PJ_STUN_STATUS_BAD_REQUEST,
+                                                    NULL, p_response);
+                    }
+                    return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_STATUS_BAD_REQUEST);
+                }
+                has_fingerprint = PJ_TRUE;
+            } else {
+                if (has_msg_int || has_fingerprint) {
+                    /* Another attribute is found which is not FINGERPRINT
+                     * after FINGERPRINT or MESSAGE-INTEGRITY */
+                    if (p_response) {
+                        pj_str_t e;
+                        e = pj_str("Invalid attribute order");
+                        pj_stun_msg_create_response(pool, msg,
+                                                    PJ_STUN_STATUS_BAD_REQUEST,
+                                                    NULL, p_response);
+                    }
+                    return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_STATUS_BAD_REQUEST);
+                }
+            }
+
             /* Make sure we have rooms for the new attribute */
             if (msg->attr_count >= PJ_STUN_MAX_ATTR) {
@@ -1716 +1764 @@
 
     return PJ_SUCCESS;
+}
+
+/* Calculate HMAC-SHA1 key for long term credential, by getting
+ * MD5 digest of username, realm, and password. 
+ */
+static void calc_md5_key(pj_uint8_t digest[16],
+                         const pj_str_t *realm,
+                         const pj_str_t *username,
+                         const pj_str_t *passwd)
+{
+    /* The 16-byte key for MESSAGE-INTEGRITY HMAC is formed by taking
+     * the MD5 hash of the result of concatenating the following five
+     * fields: (1) The username, with any quotes and trailing nulls
+     * removed, (2) A single colon, (3) The realm, with any quotes and
+     * trailing nulls removed, (4) A single colon, and (5) The 
+     * password, with any trailing nulls removed.
+     */
+    pj_md5_context ctx;
+    pj_str_t s;
+
+    pj_md5_init(&ctx);
+
+#define REMOVE_QUOTE(s) if (s.slen && *s.ptr=='"') \
+                    s.ptr++, s.slen--; \
+                if (s.slen && s.ptr[s.slen-1]=='"') \
+                    s.slen--;
+
+    /* Add username */
+    s = *username;
+    REMOVE_QUOTE(s);
+    pj_md5_update(&ctx, (pj_uint8_t*)s.ptr, s.slen);
+
+    /* Add single colon */
+    pj_md5_update(&ctx, (pj_uint8_t*)":", 1);
+
+    /* Add realm */
+    s = *realm;
+    REMOVE_QUOTE(s);
+    pj_md5_update(&ctx, (pj_uint8_t*)s.ptr, s.slen);
+
+#undef REMOVE_QUOTE
+
+    /* Another colon */
+    pj_md5_update(&ctx, (pj_uint8_t*)":", 1);
+
+    /* Add password */
+    pj_md5_update(&ctx, (pj_uint8_t*)passwd->ptr, passwd->slen);
+
+    /* Done */
+    pj_md5_final(&ctx, digest);
 }
 
@@ -1796 +1894 @@
     }
 
+    /* We MUST update the message length in the header NOW before
+     * calculating MESSAGE-INTEGRITY and FINGERPRINT. 
+     * Note that length is not including the 20 bytes header.
+     */
+    if (amsg_integrity && afingerprint) {
+        length = (pj_uint16_t)((buf - start) - 20 + 24 + 8);
+    } else if (amsg_integrity) {
+        length = (pj_uint16_t)((buf - start) - 20 + 24);
+    } else if (afingerprint) {
+        length = (pj_uint16_t)((buf - start) - 20 + 8);
+    } else {
+        length = (pj_uint16_t)((buf - start) - 20);
+    }
+
+    /* hdr->length = pj_htons(length); */
+    *(buf+2) = (pj_uint8_t)((length >> 8) & 0x00FF);
+    *(buf+3) = (pj_uint8_t)(length & 0x00FF);
+
     /* Calculate message integrity, if present */
     if (amsg_integrity != NULL) {
@@ -1836 +1952 @@
 
         } else {
-            /* The 16-byte key for MESSAGE-INTEGRITY HMAC is formed by taking
-             * the MD5 hash of the result of concatenating the following five
-             * fields: (1) The username, with any quotes and trailing nulls
-             * removed, (2) A single colon, (3) The realm, with any quotes and
-             * trailing nulls removed, (4) A single colon, and (5) The 
-             * password, with any trailing nulls removed.
-             */
-            pj_md5_context ctx;
-            pj_str_t s;
-
-            pj_md5_init(&ctx);
-
-#define REMOVE_QUOTE(s) if (s.slen && *s.ptr=='"') \
-                            s.ptr++, s.slen--; \
-                        if (s.slen && s.ptr[s.slen-1]=='"') \
-                            s.slen--;
-
-            /* Add username */
-            s = auname->value;
-            REMOVE_QUOTE(s);
-            pj_md5_update(&ctx, (pj_uint8_t*)s.ptr, s.slen);
-
-            /* Add single colon */
-            pj_md5_update(&ctx, (pj_uint8_t*)":", 1);
-
-            /* Add realm */
-            s = arealm->value;
-            REMOVE_QUOTE(s);
-            pj_md5_update(&ctx, (pj_uint8_t*)s.ptr, s.slen);
-
-#undef REMOVE_QUOTE
-
-            /* Another colon */
-            pj_md5_update(&ctx, (pj_uint8_t*)":", 1);
-
-            /* Add password */
-            pj_md5_update(&ctx, (pj_uint8_t*)password->ptr, password->slen);
-
-            /* Done */
-            pj_md5_final(&ctx, md5_key_buf);
+            calc_md5_key(md5_key_buf, &arealm->value, &auname->value, 
+                         password);
             key.ptr = (char*) md5_key_buf;
             key.slen = 16;
@@ -1910 +1988 @@
     }
 
-    /* Update the message length in the header. 
-     * Note that length is not including the 20 bytes header.
-     */
-    length = (pj_uint16_t)((buf - start) - 20);
-    /* hdr->length = pj_htons(length); */
-    *(buf+2) = (pj_uint8_t)((length >> 8) & 0x00FF);
-    *(buf+3) = (pj_uint8_t)(length & 0x00FF);
-
-
     /* Done */
     if (p_msg_len)
@@ -1946 +2015 @@
 
 
+/**************************************************************************/
+/*
+ * Authentication
+ */
+
+
+/* Send 401 response */
+static pj_status_t create_challenge(pj_pool_t *pool,
+                                    const pj_stun_msg *msg,
+                                    int err_code,
+                                    const pj_str_t *err_msg,
+                                    const pj_str_t *realm,
+                                    const pj_str_t *nonce,
+                                    pj_stun_msg **p_response)
+{
+    pj_stun_msg *response;
+    pj_status_t rc;
+
+    rc = pj_stun_msg_create_response(pool, msg, 
+                                     err_code,  err_msg, &response);
+    if (rc != PJ_SUCCESS)
+        return rc;
+
+
+    if (realm && realm->slen) {
+        rc = pj_stun_msg_add_generic_string_attr(pool, response,
+                                                 PJ_STUN_ATTR_REALM, 
+                                                 realm);
+        if (rc != PJ_SUCCESS)
+            return rc;
+    }
+
+    if (nonce && nonce->slen) {
+        rc = pj_stun_msg_add_generic_string_attr(pool, response,
+                                                 PJ_STUN_ATTR_NONCE, 
+                                                 nonce);
+        if (rc != PJ_SUCCESS)
+            return rc;
+    }
+
+    *p_response = response;
+
+    return PJ_SUCCESS;
+}
+
 /* Verify credential */
-PJ_DEF(pj_status_t) pj_stun_verify_credential( const pj_stun_msg *msg,
-                                               const pj_str_t *realm,
-                                               const pj_str_t *username,
-                                               const pj_str_t *password,
-                                               unsigned options,
+PJ_DEF(pj_status_t) pj_stun_verify_credential( const pj_uint8_t *pkt,
+                                               unsigned pkt_len,
+                                               const pj_stun_msg *msg,
+                                               pj_stun_auth_policy *pol,
                                                pj_pool_t *pool,
                                                pj_stun_msg **p_response)
 {
+    pj_str_t realm, nonce, password;
     const pj_stun_msg_integrity_attr *amsgi;
+    unsigned amsgi_pos;
     const pj_stun_username_attr *auser;
+    pj_bool_t username_ok;
     const pj_stun_realm_attr *arealm;
-
-    PJ_ASSERT_RETURN(msg && password, PJ_EINVAL);
-    PJ_ASSERT_RETURN(options==0, PJ_EINVAL);
-    PJ_UNUSED_ARG(options);
+    const pj_stun_realm_attr *anonce;
+    pj_uint8_t digest[PJ_SHA1_DIGEST_SIZE];
+    pj_uint8_t md5_digest[16];
+    pj_str_t key;
+    pj_status_t status;
+
+    /* msg and policy MUST be specified */
+    PJ_ASSERT_RETURN(pkt && pkt_len && msg && pol, PJ_EINVAL);
+
+    /* If p_response is specified, pool MUST be specified. */
+    PJ_ASSERT_RETURN(!p_response || pool, PJ_EINVAL);
 
     if (p_response)
         *p_response = NULL;
+
+    if (PJ_STUN_IS_REQUEST(msg->hdr.type))
+        p_response = NULL;
+
+    /* Get realm and nonce */
+    realm.slen = nonce.slen = 0;
+    if (pol->type == PJ_STUN_POLICY_STATIC_SHORT_TERM) {
+        realm.slen = 0;
+        nonce = pol->data.static_short_term.nonce;
+    } else if (pol->type == PJ_STUN_POLICY_STATIC_LONG_TERM) {
+        realm = pol->data.static_long_term.realm;
+        nonce = pol->data.static_long_term.nonce;
+    } else if (pol->type == PJ_STUN_POLICY_DYNAMIC) {
+        status = pol->data.dynamic.get_auth(pol->user_data, pool, 
+                                            &realm, &nonce);
+        if (status != PJ_SUCCESS)
+            return status;
+    } else {
+        pj_assert(!"Unexpected");
+        return PJ_EBUG;
+    }
 
     /* First check that MESSAGE-INTEGRITY is present */
@@ -1970 +2114 @@
             pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_MESSAGE_INTEGRITY, 0);
     if (amsgi == NULL) {
-        if (pool && p_response) {
-            pj_status_t rc;
-
-            rc = pj_stun_msg_create_response(pool, msg, 
-                                             PJ_STUN_STATUS_UNAUTHORIZED, 
-                                             NULL, p_response);
-            if (rc==PJ_SUCCESS && realm) {
-                pj_stun_msg_add_generic_string_attr(pool, *p_response,
-                                                    PJ_STUN_ATTR_REALM, 
-                                                    realm);
-            }
+        if (p_response) {
+            create_challenge(pool, msg, PJ_STUN_STATUS_UNAUTHORIZED, NULL,
+                             &realm, &nonce, p_response);
         }
         return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_STATUS_UNAUTHORIZED);
@@ -1989 +2125 @@
             pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_USERNAME, 0);
     if (auser == NULL) {
-        if (pool && p_response) {
-            pj_status_t rc;
-
-            rc = pj_stun_msg_create_response(pool, msg, 
-                                             PJ_STUN_STATUS_MISSING_USERNAME, 
-                                             NULL, p_response);
-            if (rc==PJ_SUCCESS && realm) {
-                pj_stun_msg_add_generic_string_attr(pool, *p_response,
-                                                    PJ_STUN_ATTR_REALM, 
-                                                    realm);
-            }
+        if (p_response) {
+            create_challenge(pool, msg, PJ_STUN_STATUS_MISSING_USERNAME, NULL,
+                             &realm, &nonce, p_response);
         }
         return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_STATUS_MISSING_USERNAME);
     }
 
-    /* Check if username match */
-    if (username && pj_stricmp(&auser->value, username) != 0) {
-        /* Username mismatch */
-        if (pool && p_response) {
-            pj_status_t rc;
-
-            rc = pj_stun_msg_create_response(pool, msg, 
-                                             PJ_STUN_STATUS_WRONG_USERNAME, 
-                                             NULL, p_response);
-            if (rc==PJ_SUCCESS && realm) {
-                pj_stun_msg_add_generic_string_attr(pool, *p_response,
-                                                    PJ_STUN_ATTR_REALM, 
-                                                    realm);
-            }
-        }
-        return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_STATUS_WRONG_USERNAME);
-    }
-
-    /* Next check that REALM is present */
+    /* Get REALM, if any */
     arealm = (const pj_stun_realm_attr*)
              pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_REALM, 0);
-    if (realm != NULL && arealm == NULL) {
-        /* Long term credential is required */
-        if (pool && p_response) {
-            pj_status_t rc;
-
-            rc = pj_stun_msg_create_response(pool, msg, 
-                                             PJ_STUN_STATUS_MISSING_REALM, 
-                                             NULL, p_response);
-            if (rc==PJ_SUCCESS) {
-                pj_stun_msg_add_generic_string_attr(pool, *p_response,
-                                                    PJ_STUN_ATTR_REALM, 
-                                                    realm);
-            }
+
+    /* Check if username match */
+    if (pol->type == PJ_STUN_POLICY_STATIC_SHORT_TERM) {
+        username_ok = !pj_strcmp(&auser->value, 
+                                 &pol->data.static_short_term.username);
+        password = pol->data.static_short_term.password;
+    } else if (pol->type == PJ_STUN_POLICY_STATIC_LONG_TERM) {
+        username_ok = !pj_strcmp(&auser->value, 
+                                 &pol->data.static_long_term.username);
+        password = pol->data.static_long_term.password;
+    } else if (pol->type == PJ_STUN_POLICY_DYNAMIC) {
+        pj_status_t rc;
+        rc = pol->data.dynamic.get_password(pol->user_data, 
+                                            (arealm?&arealm->value:NULL),
+                                            &auser->value, pool,
+                                            &password);
+        username_ok = (rc == PJ_SUCCESS);
+    } else {
+        username_ok = PJ_TRUE;
+        password.slen = 0;
+    }
+
+    if (!username_ok) {
+        /* Username mismatch */
+        if (p_response) {
+            create_challenge(pool, msg, PJ_STUN_STATUS_UNKNOWN_USERNAME, NULL,
+                             &realm, &nonce, p_response);
+        }
+        return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_STATUS_UNKNOWN_USERNAME);
+    }
+
+
+    /* Get NONCE attribute */
+    anonce = (pj_stun_nonce_attr*)
+             pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_NONCE, 0);
+
+    /* Check for long term/short term requirements. */
+    if (realm.slen != 0 && arealm == NULL) {
+        /* Long term credential is required and REALM is not present */
+        if (p_response) {
+            create_challenge(pool, msg, PJ_STUN_STATUS_MISSING_REALM, NULL,
+                             &realm, &nonce, p_response);
         }
         return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_STATUS_MISSING_REALM);
 
-    } else if (realm != NULL && arealm != NULL) {
-
-
-    } else if (realm == NULL && arealm != NULL) {
+    } else if (realm.slen != 0 && arealm != NULL) {
+        /* We want long term, and REALM is present */
+
+        /* NONCE must be present. */
+        if (anonce == NULL) {
+            if (p_response) {
+                create_challenge(pool, msg, PJ_STUN_STATUS_MISSING_NONCE, 
+                                 NULL, &realm, &nonce, p_response);
+            }
+            return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_STATUS_MISSING_NONCE);
+        }
+
+        /* Verify REALM matches */
+        if (pj_stricmp(&arealm->value, &realm)) {
+            /* REALM doesn't match */
+            if (p_response) {
+                create_challenge(pool, msg, PJ_STUN_STATUS_MISSING_REALM, 
+                                 NULL, &realm, &nonce, p_response);
+            }
+            return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_STATUS_MISSING_REALM);
+        }
+
+        /* Valid case, will validate the message integrity later */
+
+    } else if (realm.slen == 0 && arealm != NULL) {
         /* We want to use short term credential, but client uses long
          * term credential. The draft doesn't mention anything about
          * switching between long term and short term.
          */
-        PJ_TODO(SWITCHING_BETWEEN_SHORT_TERM_AND_LONG_TERM);
-    }
-
-    PJ_TODO(CONTINUE_IMPLEMENTATION);
-
-    return PJ_SUCCESS;
-}
-
-
+        
+        /* For now just accept the credential, anyway it will probably
+         * cause wrong message integrity value later.
+         */
+    } else if (realm.slen==0 && arealm == NULL) {
+        /* Short term authentication is wanted, and one is supplied */
+
+        /* Application MAY request NONCE to be supplied */
+        if (nonce.slen != 0) {
+            if (p_response) {
+                create_challenge(pool, msg, PJ_STUN_STATUS_MISSING_NONCE, 
+                                 NULL, &realm, &nonce, p_response);
+            }
+            return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_STATUS_MISSING_NONCE);
+        }
+    }
+
+    /* If NONCE is present, validate it */
+    if (anonce) {
+        pj_bool_t ok;
+
+        if (pol->type == PJ_STUN_POLICY_DYNAMIC) {
+            ok = pol->data.dynamic.verify_nonce(pol->user_data,
+                                                (arealm?&arealm->value:NULL),
+                                                &auser->value,
+                                                &anonce->value);
+        } else {
+            if (nonce.slen) {
+                ok = !pj_strcmp(&anonce->value, &nonce);
+            } else {
+                ok = PJ_TRUE;
+            }
+        }
+
+        if (!ok) {
+            if (p_response) {
+                create_challenge(pool, msg, PJ_STUN_STATUS_STALE_NONCE, 
+                                 NULL, &realm, &nonce, p_response);
+            }
+            return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_STATUS_STALE_NONCE);
+        }
+    }
+
+    /* Get the position of MESSAGE-INTEGRITY in the packet */
+    amsgi_pos = 20+msg->hdr.length-22;
+    if (GET_VAL16(pkt, amsgi_pos) == PJ_STUN_ATTR_MESSAGE_INTEGRITY) {
+        /* Found MESSAGE-INTEGRITY as the last attribute */
+    } else {
+        amsgi_pos = 0;
+    }
+    
+    if (amsgi_pos==0) {
+        amsgi_pos = 20+msg->hdr.length-8-22;
+        if (GET_VAL16(pkt, amsgi_pos) == PJ_STUN_ATTR_MESSAGE_INTEGRITY) {
+            /* Found MESSAGE-INTEGRITY before FINGERPRINT */
+        } else {
+            amsgi_pos = 0;
+        }
+    }
+
+    if (amsgi_pos==0) {
+        pj_assert(!"Unable to find MESSAGE-INTEGRITY in the message!");
+        return PJ_EBUG;
+    }
+
+    /* Determine which key to use */
+    if (realm.slen) {
+        calc_md5_key(md5_digest, &realm, &auser->value, &password);
+        key.ptr = (char*)md5_digest;
+        key.slen = 16;
+    } else {
+        key = password;
+    }
+
+    /* Now calculate HMAC of the message */
+    pj_hmac_sha1(pkt, amsgi_pos, (pj_uint8_t*)key.ptr, key.slen, digest);
+
+    /* Compare HMACs */
+    if (pj_memcmp(amsgi->hmac, digest, 20)) {
+        /* HMAC value mismatch */
+        if (p_response) {
+            create_challenge(pool, msg, PJ_STUN_STATUS_INTEGRITY_CHECK_FAILURE,
+                             NULL, &realm, &nonce, p_response);
+        }
+        return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_STATUS_INTEGRITY_CHECK_FAILURE);
+    }
+
+    /* Everything looks okay! */
+    return PJ_SUCCESS;
+}
+
+