Group NPN functions in their own section.

Existing documentation was moved to the header, very slightly tweaked.

Change-Id: Ife3c2351e2d7e6a335854284f996918039414446
Reviewed-on: https://boringssl-review.googlesource.com/5897
Reviewed-by: Adam Langley <agl@google.com>

ssl/ssl_lib.c

diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index 8e6fd1a..6b7be62 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -1706,39 +1706,9 @@
   return 1;
 }
 
-/* SSL_select_next_proto implements the standard protocol selection. It is
- * expected that this function is called from the callback set by
- * SSL_CTX_set_next_proto_select_cb.
- *
- * The protocol data is assumed to be a vector of 8-bit, length prefixed byte
- * strings. The length byte itself is not included in the length. A byte
- * string of length 0 is invalid. No byte string may be truncated.
- *
- * The current, but experimental algorithm for selecting the protocol is:
- *
- * 1) If the server doesn't support NPN then this is indicated to the
- * callback. In this case, the client application has to abort the connection
- * or have a default application level protocol.
- *
- * 2) If the server supports NPN, but advertises an empty list then the
- * client selects the first protcol in its list, but indicates via the
- * API that this fallback case was enacted.
- *
- * 3) Otherwise, the client finds the first protocol in the server's list
- * that it supports and selects this protocol. This is because it's
- * assumed that the server has better information about which protocol
- * a client should use.
- *
- * 4) If the client doesn't support any of the server's advertised
- * protocols, then this is treated the same as case 2.
- *
- * It returns either
- * OPENSSL_NPN_NEGOTIATED if a common protocol was found, or
- * OPENSSL_NPN_NO_OVERLAP if the fallback case was reached.
- */
-int SSL_select_next_proto(uint8_t **out, uint8_t *outlen, const uint8_t *server,
-                          unsigned int server_len, const uint8_t *client,
-                          unsigned int client_len) {
+int SSL_select_next_proto(uint8_t **out, uint8_t *out_len,
+                          const uint8_t *server, unsigned server_len,
+                          const uint8_t *client, unsigned client_len) {
   unsigned int i, j;
   const uint8_t *result;
   int status = OPENSSL_NPN_UNSUPPORTED;
@@ -1766,57 +1736,31 @@
 
 found:
   *out = (uint8_t *)result + 1;
-  *outlen = result[0];
+  *out_len = result[0];
   return status;
 }
 
-/* SSL_get0_next_proto_negotiated sets *data and *len to point to the client's
- * requested protocol for this connection and returns 0. If the client didn't
- * request any protocol, then *data is set to NULL.
- *
- * Note that the client can request any protocol it chooses. The value returned
- * from this function need not be a member of the list of supported protocols
- * provided by the callback. */
-void SSL_get0_next_proto_negotiated(const SSL *s, const uint8_t **data,
-                                    unsigned *len) {
-  *data = s->next_proto_negotiated;
-  if (!*data) {
-    *len = 0;
+void SSL_get0_next_proto_negotiated(const SSL *ssl, const uint8_t **out_data,
+                                    unsigned *out_len) {
+  *out_data = ssl->next_proto_negotiated;
+  if (*out_data == NULL) {
+    *out_len = 0;
   } else {
-    *len = s->next_proto_negotiated_len;
+    *out_len = ssl->next_proto_negotiated_len;
   }
 }
 
-/* SSL_CTX_set_next_protos_advertised_cb sets a callback that is called when a
- * TLS server needs a list of supported protocols for Next Protocol
- * Negotiation. The returned list must be in wire format.  The list is returned
- * by setting |out| to point to it and |outlen| to its length. This memory will
- * not be modified, but one should assume that the SSL* keeps a reference to
- * it.
- *
- * The callback should return SSL_TLSEXT_ERR_OK if it wishes to advertise.
- * Otherwise, no such extension will be included in the ServerHello. */
 void SSL_CTX_set_next_protos_advertised_cb(
     SSL_CTX *ctx,
-    int (*cb)(SSL *ssl, const uint8_t **out, unsigned int *outlen, void *arg),
+    int (*cb)(SSL *ssl, const uint8_t **out, unsigned *out_len, void *arg),
     void *arg) {
   ctx->next_protos_advertised_cb = cb;
   ctx->next_protos_advertised_cb_arg = arg;
 }
 
-/* SSL_CTX_set_next_proto_select_cb sets a callback that is called when a
- * client needs to select a protocol from the server's provided list. |out|
- * must be set to point to the selected protocol (which may be within |in|).
- * The length of the protocol name must be written into |outlen|. The server's
- * advertised protocols are provided in |in| and |inlen|. The callback can
- * assume that |in| is syntactically valid.
- *
- * The client must select a protocol. It is fatal to the connection if this
- * callback returns a value other than SSL_TLSEXT_ERR_OK.
- */
 void SSL_CTX_set_next_proto_select_cb(
-    SSL_CTX *ctx, int (*cb)(SSL *s, uint8_t **out, uint8_t *outlen,
-                            const uint8_t *in, unsigned int inlen, void *arg),
+    SSL_CTX *ctx, int (*cb)(SSL *ssl, uint8_t **out, uint8_t *out_len,
+                            const uint8_t *in, unsigned in_len, void *arg),
     void *arg) {
   ctx->next_proto_select_cb = cb;
   ctx->next_proto_select_cb_arg = arg;