2 * Copyright (C) 2016 "IoT.bzh"
3 * Author: José Bollo <jose.bollo@iot.bzh>
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
25 #include <openssl/sha.h>
26 #include <microhttpd.h>
28 #include "afb-method.h"
29 #include "afb-context.h"
31 #include "afb-websock.h"
32 #include "afb-ws-json1.h"
34 /**************** WebSocket connection upgrade ****************************/
36 static const char websocket_s[] = "websocket";
37 static const char sec_websocket_key_s[] = "Sec-WebSocket-Key";
38 static const char sec_websocket_version_s[] = "Sec-WebSocket-Version";
39 static const char sec_websocket_accept_s[] = "Sec-WebSocket-Accept";
40 static const char sec_websocket_protocol_s[] = "Sec-WebSocket-Protocol";
41 static const char websocket_guid[] = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
43 static void enc64(unsigned char *in, char *out)
45 static const char tob64[] =
46 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
47 "abcdefghijklmnopqrstuvwxyz"
49 out[0] = tob64[in[0] >> 2];
50 out[1] = tob64[((in[0] & 0x03) << 4) | ((in[1] & 0xf0) >> 4)];
51 out[2] = tob64[((in[1] & 0x0f) << 2) | ((in[2] & 0xc0) >> 6)];
52 out[3] = tob64[in[2] & 0x3f];
55 static void make_accept_value(const char *key, char result[29])
57 unsigned char md[SHA_DIGEST_LENGTH+1];
58 size_t len = strlen(key);
59 char *buffer = alloca(len + sizeof websocket_guid - 1);
60 memcpy(buffer, key, len);
61 memcpy(buffer + len, websocket_guid, sizeof websocket_guid - 1);
62 SHA1((const unsigned char *)buffer, (unsigned long)(len + sizeof websocket_guid - 1), md);
63 assert(SHA_DIGEST_LENGTH == 20);
65 enc64(&md[0], &result[0]);
66 enc64(&md[3], &result[4]);
67 enc64(&md[6], &result[8]);
68 enc64(&md[9], &result[12]);
69 enc64(&md[12], &result[16]);
70 enc64(&md[15], &result[20]);
71 enc64(&md[18], &result[24]);
76 static const char vseparators[] = " \t,";
78 static int headerhas(const char *header, const char *needle)
84 header += strspn(header, vseparators);
87 len = strcspn(header, vseparators);
88 if (n == len && 0 == strncasecmp(needle, header, n))
97 void *(*create)(int fd, void *context, void (*cleanup)(void*), void *cleanup_closure);
100 static const struct protodef *search_proto(const struct protodef *protodefs, const char *protocols)
105 if (protocols == NULL) {
107 return protodefs != NULL && protodefs->name != NULL ? protodefs : NULL;
110 protocols += strspn(protocols, vseparators);
113 len = strcspn(protocols, vseparators);
114 for (i = 0 ; protodefs[i].name != NULL ; i++)
115 if (!strncasecmp(protodefs[i].name, protocols, len)
116 && !protodefs[i].name[len])
117 return &protodefs[i];
122 static int check_websocket_upgrade(struct MHD_Connection *con, const struct protodef *protodefs, void *context, void **websock)
124 const union MHD_ConnectionInfo *info;
125 struct MHD_Response *response;
126 const char *connection, *upgrade, *key, *version, *protocols;
129 const struct protodef *proto;
132 /* is an upgrade to websocket ? */
133 upgrade = MHD_lookup_connection_value(con, MHD_HEADER_KIND, MHD_HTTP_HEADER_UPGRADE);
134 if (upgrade == NULL || strcasecmp(upgrade, websocket_s))
137 /* is a connection for upgrade ? */
138 connection = MHD_lookup_connection_value(con, MHD_HEADER_KIND, MHD_HTTP_HEADER_CONNECTION);
139 if (connection == NULL
140 || !headerhas (connection, MHD_HTTP_HEADER_UPGRADE))
143 /* has a key and a version ? */
144 key = MHD_lookup_connection_value(con, MHD_HEADER_KIND, sec_websocket_key_s);
145 version = MHD_lookup_connection_value(con, MHD_HEADER_KIND, sec_websocket_version_s);
146 if (key == NULL || version == NULL)
149 /* is a supported version ? */
150 vernum = atoi(version);
152 response = MHD_create_response_from_buffer(0, NULL, MHD_RESPMEM_PERSISTENT);
153 MHD_add_response_header(response, sec_websocket_version_s, "13");
154 MHD_queue_response(con, MHD_HTTP_UPGRADE_REQUIRED, response);
155 MHD_destroy_response(response);
159 /* is the protocol supported ? */
160 protocols = MHD_lookup_connection_value(con, MHD_HEADER_KIND, sec_websocket_protocol_s);
161 proto = search_proto(protodefs, protocols);
163 response = MHD_create_response_from_buffer(0, NULL, MHD_RESPMEM_PERSISTENT);
164 MHD_queue_response(con, MHD_HTTP_PRECONDITION_FAILED, response);
165 MHD_destroy_response(response);
169 /* create the web socket */
170 info = MHD_get_connection_info(con, MHD_CONNECTION_INFO_CONNECTION_FD);
172 response = MHD_create_response_from_buffer(0, NULL, MHD_RESPMEM_PERSISTENT);
173 MHD_queue_response(con, MHD_HTTP_INTERNAL_SERVER_ERROR, response);
174 MHD_destroy_response(response);
177 ws = proto->create(info->connect_fd, context, (void*)MHD_resume_connection, con);
179 response = MHD_create_response_from_buffer(0, NULL, MHD_RESPMEM_PERSISTENT);
180 MHD_queue_response(con, MHD_HTTP_INTERNAL_SERVER_ERROR, response);
181 MHD_destroy_response(response);
185 /* send the accept connection */
186 make_accept_value(key, acceptval);
187 response = MHD_create_response_from_buffer(0, NULL, MHD_RESPMEM_PERSISTENT);
188 MHD_add_response_header(response, sec_websocket_accept_s, acceptval);
189 MHD_add_response_header(response, sec_websocket_protocol_s, proto->name);
190 MHD_add_response_header(response, MHD_HTTP_HEADER_CONNECTION, MHD_HTTP_HEADER_UPGRADE);
191 MHD_add_response_header(response, MHD_HTTP_HEADER_UPGRADE, websocket_s);
192 MHD_queue_response(con, MHD_HTTP_SWITCHING_PROTOCOLS, response);
193 MHD_destroy_response(response);
199 static const struct protodef protodefs[] = {
200 { "x-afb-ws-json1", (void*)afb_ws_json1_create },
204 int afb_websock_check_upgrade(struct afb_hreq *hreq)
210 if (hreq->method != afb_method_get
211 || strcasecmp(hreq->version, MHD_HTTP_VERSION_1_1))
215 rc = check_websocket_upgrade(hreq->connection, protodefs, &hreq->context, &ws);