Add specific SSL error code for unexpected CIDs
Currently, the stack silently ignores DTLS frames with an unexpected CID.
However, in a system which performs CID-based demultiplexing before passing
datagrams to the Mbed TLS stack, unexpected CIDs are a sign of something not
working properly, and users might want to know about it.
This commit introduces an SSL error code MBEDTLS_ERR_SSL_UNEXPECTED_CID
which the stack can return in response to an unexpected CID. It will
conditionally be put to use in subsequent commits.
diff --git a/include/mbedtls/error.h b/include/mbedtls/error.h
index bee0fe4..765fd42 100644
--- a/include/mbedtls/error.h
+++ b/include/mbedtls/error.h
@@ -100,8 +100,8 @@
* ECP 4 10 (Started from top)
* MD 5 5
* HKDF 5 1 (Started from top)
- * CIPHER 6 8
- * SSL 6 23 (Started from top)
+ * CIPHER 6 8 (Started from 0x6080)
+ * SSL 6 24 (Started from top, plus 0x6000)
* SSL 7 32
*
* Module dependent error code (5 bits 0x.00.-0x.F8.)
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 909258c..b616a73 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -126,6 +126,7 @@
#define MBEDTLS_ERR_SSL_CONTINUE_PROCESSING -0x6580 /**< Internal-only message signaling that further message-processing should be done */
#define MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS -0x6500 /**< The asynchronous operation is not completed yet. */
#define MBEDTLS_ERR_SSL_EARLY_MESSAGE -0x6480 /**< Internal-only message signaling that a message arrived early. */
+#define MBEDTLS_ERR_SSL_UNEXPECTED_CID -0x6000 /**< An encrypted DTLS-frame with an unexpected CID was received. */
#define MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS -0x7000 /**< A cryptographic operation is in progress. Try again later. */
/*
diff --git a/library/error.c b/library/error.c
index 608423b..e401a84 100644
--- a/library/error.c
+++ b/library/error.c
@@ -523,6 +523,8 @@
mbedtls_snprintf( buf, buflen, "SSL - The asynchronous operation is not completed yet" );
if( use_ret == -(MBEDTLS_ERR_SSL_EARLY_MESSAGE) )
mbedtls_snprintf( buf, buflen, "SSL - Internal-only message signaling that a message arrived early" );
+ if( use_ret == -(MBEDTLS_ERR_SSL_UNEXPECTED_CID) )
+ mbedtls_snprintf( buf, buflen, "SSL - An encrypted DTLS-frame with an unexpected CID was received" );
if( use_ret == -(MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS) )
mbedtls_snprintf( buf, buflen, "SSL - A cryptographic operation is in progress. Try again later" );
#endif /* MBEDTLS_SSL_TLS_C */