Move the session ticket functions to ssl.h.

Having them spread between ssl.h and tls1.h isn't terribly enlightening.

Change-Id: I5fec4b8e5260312b22bcef21bd4db7a8a8149ad8
Reviewed-on: https://boringssl-review.googlesource.com/5234
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index 6a04055..84897f1 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -584,6 +584,49 @@
                                       size_t *out_len, size_t max_out);
 
 
+/* Session tickets. */
+
+/* SSL_CTX_get_tlsext_ticket_keys writes |ctx|'s session ticket key material to
+ * |len| bytes of |out|. It returns one on success and zero if |len| is not
+ * 48. If |out| is NULL, it returns 48 instead. */
+OPENSSL_EXPORT int SSL_CTX_get_tlsext_ticket_keys(SSL_CTX *ctx, void *out,
+                                                  size_t len);
+
+/* SSL_CTX_set_tlsext_ticket_keys sets |ctx|'s session ticket key material to
+ * |len| bytes of |in|. It returns one on success and zero if |len| is not
+ * 48. If |in| is NULL, it returns 48 instead. */
+OPENSSL_EXPORT int SSL_CTX_set_tlsext_ticket_keys(SSL_CTX *ctx, const void *in,
+                                                  size_t len);
+
+/* SSL_CTX_set_tlsext_ticket_key_cb sets the ticket callback to |callback| and
+ * returns one. |callback| will be called when encrypting a new ticket and when
+ * decrypting a ticket from the client.
+ *
+ * In both modes, |ctx| and |hmac_ctx| will already have been initialized with
+ * |EVP_CIPHER_CTX_init| and |HMAC_CTX_init|, respectively. |callback|
+ * configures |hmac_ctx| with an HMAC digest and key, and configures |ctx|
+ * for encryption or decryption, based on the mode.
+ *
+ * When encrypting a new ticket, |encrypt| will be one. It writes a public
+ * 16-byte key name to |key_name| and a fresh IV to |iv|. The output IV length
+ * must match |EVP_CIPHER_CTX_iv_length| of the cipher selected. In this mode,
+ * |callback| returns 1 on success and -1 on error.
+ *
+ * When decrypting a ticket, |encrypt| will be zero. |key_name| will point to a
+ * 16-byte key name and |iv| points to an IV. The length of the IV consumed must
+ * match |EVP_CIPHER_CTX_iv_length| of the cipher selected. In this mode,
+ * |callback| returns -1 to abort the handshake, 0 if decrypting the ticket
+ * failed, and 1 or 2 on success. If it returns 2, the ticket will be renewed.
+ * This may be used to re-key the ticket.
+ *
+ * WARNING: |callback| wildly breaks the usual return value convention and is
+ * called in two different modes. */
+OPENSSL_EXPORT int SSL_CTX_set_tlsext_ticket_key_cb(
+    SSL_CTX *ctx, int (*callback)(SSL *ssl, uint8_t *key_name, uint8_t *iv,
+                                  EVP_CIPHER_CTX *ctx, HMAC_CTX *hmac_ctx,
+                                  int encrypt));
+
+
 /* Underdocumented functions.
  *
  * Functions below here haven't been touched up and may be underdocumented. */