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res/res_http_websocket: Add a pre-session established callback

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This patch updates http_websocket and its corresponding implementation
with a pre-session established callback. This callback allows for
WebSocket server consumers to be notified when a WebSocket connection is
attempted, but before we accept it. Consumers can choose to reject the
connection, if their application specific logic allows for it.

As a result, this patch pulls out the previously private
websocket_protocol struct and makes it public, as
ast_websocket_protocol. In order to preserve backwards compatibility
with existing modules, the existing APIs were left as-is, and new APIs
were added for the creation of the ast_websocket_protocol as well as for
adding a sub-protocol to a WebSocket server.

In particular, the following new API calls were added:
* ast_websocket_add_protocol2 - add a protocol to the core WebSocket
  server
* ast_websocket_server_add_protocol2 - add a protocol to a specific
  WebSocket server
* ast_websocket_sub_protocol_alloc - allocate a sub-protocol object.
  Consumers can populate this with whatever callbacks they wish to
  support, then add it to the core server or a specified server.

ASTERISK-24988
Reported by: Joshua Colp

Change-Id: Ibe0bbb30c17eec6b578071bdbd197c911b620ab2
This commit is contained in:
Matt Jordan
2015-05-13 09:55:58 -05:00
parent ddb7cbef8e
commit 5ce54ed74a
2 changed files with 172 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files

86
include/asterisk/http_websocket.h
View File

@@ -67,6 +67,24 @@ struct ast_websocket_server;
*/
struct ast_websocket;
/*!
* \brief Callback from the HTTP request attempting to establish a websocket connection
*
* This callback occurs when an HTTP request is made to establish a websocket connection.
* Implementers of \ref ast_websocket_protocol can use this to deny a request, or to
* set up application specific data before invocation of \ref ast_websocket_callback.
*
* \param ser The TCP/TLS session
* \param parameters Parameters extracted from the request URI
* \param headers Headers included in the request
*
* \retval 0 The session should be accepted
* \retval -1 The session should be rejected. Note that the caller must send an error
* response using \ref ast_http_error.
* \since 13.5.0
*/
typedef int (*ast_websocket_pre_callback)(struct ast_tcptls_session_instance *ser, struct ast_variable *parameters, struct ast_variable *headers);
/*!
* \brief Callback for when a new connection for a sub-protocol is established
*
@@ -80,6 +98,32 @@ struct ast_websocket;
*/
typedef void (*ast_websocket_callback)(struct ast_websocket *session, struct ast_variable *parameters, struct ast_variable *headers);
/*!
* \brief A websocket protocol implementation
*
* Users of the Websocket API can register themselves as a websocket
* protocol. See \ref ast_websocket_add_protocol2 and \ref ast_websocket_server_add_protocol2.
* Simpler implementations may use only \ref ast_websocket_add_protocol and
* \ref ast_websocket_server_add_protocol.
*
* \since 13.5.0
*/
struct ast_websocket_protocol {
/*! \brief Name of the protocol */
char *name;
/*!
* \brief Protocol version. This prevents dynamically loadable modules from registering
* if this struct is changed.
*/
#define AST_WEBSOCKET_PROTOCOL_VERSION 1
/*! \brief Protocol version. Should be set to /ref AST_WEBSOCKET_PROTOCOL_VERSION */
unsigned int version;
/*! \brief Callback called when a new session is attempted. Optional. */
ast_websocket_pre_callback session_attempted;
/* \brief Callback called when a new session is established. Mandatory. */
ast_websocket_callback session_established;
};
/*!
* \brief Creates a \ref websocket_server
*
@@ -97,6 +141,15 @@ AST_OPTIONAL_API(struct ast_websocket_server *, ast_websocket_server_create, (vo
*/
AST_OPTIONAL_API(int, ast_websocket_uri_cb, (struct ast_tcptls_session_instance *ser, const struct ast_http_uri *urih, const char *uri, enum ast_http_method method, struct ast_variable *get_vars, struct ast_variable *headers), { return -1; });
/*!
* \brief Allocate a websocket sub-protocol instance
*
* \retval An instance of \ref ast_websocket_protocol on success
* \retval NULL on error
* \since 13.5.0
*/
AST_OPTIONAL_API(struct ast_websocket_protocol *, ast_websocket_sub_protocol_alloc, (const char *name), {return NULL;});
/*!
* \brief Add a sub-protocol handler to the default /ws server
*
@@ -108,11 +161,26 @@ AST_OPTIONAL_API(int, ast_websocket_uri_cb, (struct ast_tcptls_session_instance
*/
AST_OPTIONAL_API(int, ast_websocket_add_protocol, (const char *name, ast_websocket_callback callback), {return -1;});
/*!
* \brief Add a sub-protocol handler to the default /ws server
*
* \param protocol The sub-protocol to register. Note that this must
* be allocated using /ref ast_websocket_sub_protocol_alloc.
*
* \note This method is reference stealing. It will steal the reference to \ref protocol
* on success.
*
* \retval 0 success
* \retval -1 if sub-protocol handler could not be registered
* \since 13.5.0
*/
AST_OPTIONAL_API(int, ast_websocket_add_protocol2, (struct ast_websocket_protocol *protocol), {return -1;});
/*!
* \brief Remove a sub-protocol handler from the default /ws server.
*
* \param name Name of the sub-protocol to unregister
* \param callback Callback that was previously registered with the sub-protocol
* \param callback Session Established callback that was previously registered with the sub-protocol
*
* \retval 0 success
* \retval -1 if sub-protocol was not found or if callback did not match
@@ -131,6 +199,22 @@ AST_OPTIONAL_API(int, ast_websocket_remove_protocol, (const char *name, ast_webs
*/
AST_OPTIONAL_API(int, ast_websocket_server_add_protocol, (struct ast_websocket_server *server, const char *name, ast_websocket_callback callback), {return -1;});
/*!
* \brief Add a sub-protocol handler to the given server.
*
* \param server The server to add the sub-protocol to.
* \param protocol The sub-protocol to register. Note that this must
* be allocated using /ref ast_websocket_sub_protocol_alloc.
*
* \note This method is reference stealing. It will steal the reference to \ref protocol
* on success.
*
* \retval 0 success
* \retval -1 if sub-protocol handler could not be registered
* \since 13.5.0
*/
AST_OPTIONAL_API(int, ast_websocket_server_add_protocol2, (struct ast_websocket_server *server, struct ast_websocket_protocol *protocol), {return -1;});
/*!
* \brief Remove a sub-protocol handler from the given server.
*

119
res/res_http_websocket.c
View File

@@ -88,16 +88,10 @@ struct ast_websocket {
struct websocket_client *client; /*!< Client object when connected as a client websocket */
};
/*! \brief Structure definition for protocols */
struct websocket_protocol {
char *name; /*!< Name of the protocol */
ast_websocket_callback callback; /*!< Callback called when a new session is established */
};
/*! \brief Hashing function for protocols */
static int protocol_hash_fn(const void *obj, const int flags)
{
const struct websocket_protocol *protocol = obj;
const struct ast_websocket_protocol *protocol = obj;
const char *name = obj;
return ast_str_case_hash(flags & OBJ_KEY ? name : protocol->name);
@@ -106,7 +100,7 @@ static int protocol_hash_fn(const void *obj, const int flags)
/*! \brief Comparison function for protocols */
static int protocol_cmp_fn(void *obj, void *arg, int flags)
{
const struct websocket_protocol *protocol1 = obj, *protocol2 = arg;
const struct ast_websocket_protocol *protocol1 = obj, *protocol2 = arg;
const char *protocol = arg;
return !strcasecmp(protocol1->name, flags & OBJ_KEY ? protocol : protocol2->name) ? CMP_MATCH | CMP_STOP : 0;
@@ -115,7 +109,7 @@ static int protocol_cmp_fn(void *obj, void *arg, int flags)
/*! \brief Destructor function for protocols */
static void protocol_destroy_fn(void *obj)
{
struct websocket_protocol *protocol = obj;
struct ast_websocket_protocol *protocol = obj;
ast_free(protocol->name);
}
@@ -182,54 +176,91 @@ static void session_destroy_fn(void *obj)
ast_free(session->payload);
}
struct ast_websocket_protocol *AST_OPTIONAL_API_NAME(ast_websocket_sub_protocol_alloc)(const char *name)
{
struct ast_websocket_protocol *protocol;
protocol = ao2_alloc(sizeof(*protocol), protocol_destroy_fn);
if (!protocol) {
return NULL;
}
protocol->name = ast_strdup(name);
if (!protocol->name) {
ao2_ref(protocol, -1);
return NULL;
}
protocol->version = AST_WEBSOCKET_PROTOCOL_VERSION;
return protocol;
}
int AST_OPTIONAL_API_NAME(ast_websocket_server_add_protocol)(struct ast_websocket_server *server, const char *name, ast_websocket_callback callback)
{
struct websocket_protocol *protocol;
struct ast_websocket_protocol *protocol;
if (!server->protocols) {
return -1;
}
protocol = ast_websocket_sub_protocol_alloc(name);
if (!protocol) {
ao2_unlock(server->protocols);
return -1;
}
protocol->session_established = callback;
if (ast_websocket_server_add_protocol2(server, protocol)) {
ao2_ref(protocol, -1);
return -1;
}
return 0;
}
int AST_OPTIONAL_API_NAME(ast_websocket_server_add_protocol2)(struct ast_websocket_server *server, struct ast_websocket_protocol *protocol)
{
struct ast_websocket_protocol *existing;
if (!server->protocols) {
return -1;
}
if (protocol->version != AST_WEBSOCKET_PROTOCOL_VERSION) {
ast_log(LOG_WARNING, "WebSocket could not register sub-protocol '%s': "
"expected version '%u', got version '%u'\n",
protocol->name, AST_WEBSOCKET_PROTOCOL_VERSION, protocol->version);
return -1;
}
ao2_lock(server->protocols);
/* Ensure a second protocol handler is not registered for the same protocol */
if ((protocol = ao2_find(server->protocols, name, OBJ_KEY | OBJ_NOLOCK))) {
ao2_ref(protocol, -1);
existing = ao2_find(server->protocols, protocol->name, OBJ_KEY | OBJ_NOLOCK);
if (existing) {
ao2_ref(existing, -1);
ao2_unlock(server->protocols);
return -1;
}
if (!(protocol = ao2_alloc(sizeof(*protocol), protocol_destroy_fn))) {
ao2_unlock(server->protocols);
return -1;
}
if (!(protocol->name = ast_strdup(name))) {
ao2_ref(protocol, -1);
ao2_unlock(server->protocols);
return -1;
}
protocol->callback = callback;
ao2_link_flags(server->protocols, protocol, OBJ_NOLOCK);
ao2_unlock(server->protocols);
ao2_ref(protocol, -1);
ast_verb(2, "WebSocket registered sub-protocol '%s'\n", name);
ast_verb(2, "WebSocket registered sub-protocol '%s'\n", protocol->name);
ao2_ref(protocol, -1);
return 0;
}
int AST_OPTIONAL_API_NAME(ast_websocket_server_remove_protocol)(struct ast_websocket_server *server, const char *name, ast_websocket_callback callback)
{
struct websocket_protocol *protocol;
struct ast_websocket_protocol *protocol;
if (!(protocol = ao2_find(server->protocols, name, OBJ_KEY))) {
return -1;
}
if (protocol->callback != callback) {
if (protocol->session_established != callback) {
ao2_ref(protocol, -1);
return -1;
}
@@ -600,7 +631,7 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha
/*!
* \brief If the server has exactly one configured protocol, return it.
*/
static struct websocket_protocol *one_protocol(
static struct ast_websocket_protocol *one_protocol(
struct ast_websocket_server *server)
{
SCOPED_AO2LOCK(lock, server->protocols);
@@ -643,7 +674,7 @@ int AST_OPTIONAL_API_NAME(ast_websocket_uri_cb)(struct ast_tcptls_session_instan
struct ast_variable *v;
char *upgrade = NULL, *key = NULL, *key1 = NULL, *key2 = NULL, *protos = NULL, *requested_protocols = NULL, *protocol = NULL;
int version = 0, flags = 1;
struct websocket_protocol *protocol_handler = NULL;
struct ast_websocket_protocol *protocol_handler = NULL;
struct ast_websocket *session;
struct ast_websocket_server *server;
@@ -742,6 +773,14 @@ int AST_OPTIONAL_API_NAME(ast_websocket_uri_cb)(struct ast_tcptls_session_instan
}
session->timeout = AST_DEFAULT_WEBSOCKET_WRITE_TIMEOUT;
if (protocol_handler->session_attempted
&& protocol_handler->session_attempted(ser, get_vars, headers)) {
ast_debug(3, "WebSocket connection from '%s' rejected by protocol handler '%s'\n",
ast_sockaddr_stringify(&ser->remote_address), protocol_handler->name);
ao2_ref(protocol_handler, -1);
return 0;
}
fprintf(ser->f, "HTTP/1.1 101 Switching Protocols\r\n"
"Upgrade: %s\r\n"
"Connection: Upgrade\r\n"
@@ -797,7 +836,7 @@ int AST_OPTIONAL_API_NAME(ast_websocket_uri_cb)(struct ast_tcptls_session_instan
/* Give up ownership of the socket and pass it to the protocol handler */
ast_tcptls_stream_set_exclusive_input(ser->stream_cookie, 0);
protocol_handler->callback(session, get_vars, headers);
protocol_handler->session_established(session, get_vars, headers);
ao2_ref(protocol_handler, -1);
/*
@@ -881,6 +920,22 @@ int AST_OPTIONAL_API_NAME(ast_websocket_add_protocol)(const char *name, ast_webs
return res;
}
int AST_OPTIONAL_API_NAME(ast_websocket_add_protocol2)(struct ast_websocket_protocol *protocol)
{
struct ast_websocket_server *ws_server = websocketuri.data;
if (!ws_server) {
return -1;
}
if (ast_websocket_server_add_protocol2(ws_server, protocol)) {
return -1;
}
ast_module_ref(ast_module_info->self);
return 0;
}
static int websocket_remove_protocol_internal(const char *name, ast_websocket_callback callback)
{
struct ast_websocket_server *ws_server = websocketuri.data;