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/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. */
/*