1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
|
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <sys/signalfd.h>
#include <unistd.h>
#include <cJSON.h>
#include <curl/curl.h>
#include <init.h>
#include <log.h>
#include <subsys.h>
extern int http_get(char *url);
extern void ws_handle_event(cJSON *event);
extern void ws_send_heartbeat();
CURL *ws_handle;
char *gateway_url;
int net_subsystem(void)
{
print(LOG_INFO "net: starting net subsystem");
if(!gateway_url)
panic("net: gateway url invalid");
/* Initialise CURL */
ws_handle = curl_easy_init();
curl_easy_setopt(ws_handle, CURLOPT_URL, gateway_url);
curl_easy_setopt(ws_handle, CURLOPT_CONNECT_ONLY, 2L);
print(LOG_INFO "net: opening ws");
CURLcode ret = curl_easy_perform(ws_handle);
if(ret > 0) {
panic("net: cannot open websocket: %s", curl_easy_strerror(ret));
}
int ws_sockfd;
if((ret = curl_easy_getinfo(ws_handle,
CURLINFO_ACTIVESOCKET, &ws_sockfd)) != CURLE_OK)
panic("net: curl cannot get active socket: "
"%s", curl_easy_strerror(ret));
/* Block ALRM */
sigset_t *set = malloc(sizeof(sigset_t));
sigemptyset(set);
sigaddset(set, SIGALRM);
sigprocmask(SIG_BLOCK, set, NULL);
int alrmfd = signalfd(-1, set, 0);
free(set);
/* Prepare poll */
struct pollfd pollarray[2] = {
{
.fd = ws_sockfd,
.events = POLLIN,
.revents = POLLIN
},
{
.fd = alrmfd,
.events = POLLIN,
.revents = 0
}
};
struct pollfd *sockpoll = &(pollarray[0]);
struct pollfd *alrmpoll = &(pollarray[1]);
/* Misc. variables */
char *inbuf = malloc(1<<16 * sizeof(char));
size_t rlen;
const struct curl_ws_frame *meta;
errno = 0;
do {
if((sockpoll->revents & POLLIN) == POLLIN) {
ret = curl_ws_recv(ws_handle, inbuf, 1<<16, &rlen, &meta);
/* sometimes only SSL information gets sent through, so no actual
data is received. curl uses NONBLOCK internally so it lets us
know if there is no more data remaining */
if(ret == CURLE_AGAIN)
continue;
if(ret != CURLE_OK) {
print(LOG_ERR "net: encountered error while reading socket: "
"%s", curl_easy_strerror(ret));
break;
}
/* TODO: partial frames */
if((meta->offset | meta->bytesleft) > 0) {
print(LOG_ERR "net: dropped partial frame");
continue;
}
cJSON *event = cJSON_ParseWithLength(inbuf, rlen);
if(!event) {
print(LOG_ERR "net: dropped malformed frame");
continue;
}
ws_handle_event(event);
cJSON_Delete(event);
} else if((sockpoll->revents &
(POLLRDHUP | POLLERR | POLLHUP | POLLNVAL)) > 0) {
break;
}
if((alrmpoll->revents & POLLIN) == POLLIN) {
struct signalfd_siginfo siginfo;
read(alrmfd, &siginfo, sizeof(struct signalfd_siginfo));
ws_send_heartbeat();
}
} while(poll(pollarray, 2, -1) >= 0);
if(errno > 0) {
print(LOG_ERR "net: poll: %s", strerror(errno));
}
free(inbuf);
curl_easy_cleanup(ws_handle);
panic("net: websocket closed unexpectedly");
return 0;
}
void net_get_gateway_url()
{
/* determine if websockets are supported */
curl_version_info_data *curl_version =
curl_version_info(CURLVERSION_NOW);
const char * const* curl_protocols = curl_version->protocols;
int wss_supported = 0;
for(int i = 0; curl_protocols[i]; ++i) {
if(strcmp(curl_protocols[i], "wss") == 0) {
wss_supported = 1;
break;
}
}
if(!wss_supported)
panic("net: wss not supported by libcurl");
/* fetch preferred url from discord */
int fd = http_get("https://discord.com/api/gateway/bot");
if(fd < 0) {
print(LOG_ERR "net: cannot get gateway url: %s", curl_easy_strerror(-fd));
goto assume;
}
char buf[512];
int buf_length = read(fd, buf, 512);
close(fd);
cJSON *gateway_info = cJSON_ParseWithLength(buf, buf_length);
cJSON *gateway_url_json =
cJSON_GetObjectItemCaseSensitive(gateway_info, "url");
if(!cJSON_IsString(gateway_url_json) ||
gateway_url_json->valuestring == NULL) {
cJSON *gateway_message =
cJSON_GetObjectItemCaseSensitive(gateway_info, "message");
if(cJSON_IsString(gateway_message)) {
print(LOG_ERR "net: cannot get gateway url from api: "
"%s", cJSON_GetStringValue(gateway_message));
} else {
print(LOG_ERR "net: cannot get gateway url from api "
"(unknown error)");
}
cJSON_Delete(gateway_info);
goto assume;
}
/* curl requires websocket secure URLs to begin with WSS instead
of wss, so we fix up the received url for curl */
gateway_url = calloc(strlen(gateway_url_json->valuestring) + 1,
sizeof(char));
strcpy(gateway_url, gateway_url_json->valuestring);
gateway_url[0] = 'W';
gateway_url[1] = 'S';
gateway_url[2] = 'S';
print(LOG_DEBUG "net: using gateway url %s", gateway_url);
cJSON_Delete(gateway_info);
return;
assume:
print(LOG_DEBUG "net: assuming gateway url WSS://gateway.discord.gg");
gateway_url = calloc(strlen("WSS://gateway.discord.gg") + 1,
sizeof(char));
strcpy(gateway_url, "WSS://gateway.discord.gg");
return;
}
l1_initcall(net_get_gateway_url);
void net_initcall()
{
start_subsystem(net_subsystem);
}
l2_initcall(net_initcall);
|
