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
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
|
/* /Net/dxcern/userd/timbl/hypertext/WWW/Library/src/HTTCP.html
GENERIC NETWORK COMMUNICATION
This module has the common code for handling TCP/IP and DECnet connections etc. The
module is a part of the CERN Common WWW Library.
*/
#ifndef HTTCP_H
#define HTTCP_H
#include "HTUtils.h"
#include "HTAccess.h"
#ifdef SHORT_NAMES
#define HTInetStatus HTInStat
#define HTInetString HTInStri
#define HTParseInet HTPaInet
#endif
/*
Connection Management
All connections are established through these two functions.
ACTIVE CONNECTION ESTABLISHMENT
This makes an active connect to the specified host. The HTNetInfo structure is parsed
in order to handle errors. Default port might be overwritten by any port indication in
the URL specified as <host>:<port> If it is a multihomed host then HTDoConnect measures
the time to do the connection and updates the calculated weights in the cache of
visited hosts.
*/
PUBLIC int HTDoConnect PARAMS(( HTNetInfo *net,
char *url,
u_short default_port,
u_long *addr,
BOOL use_cur));
/*
PASSIVE CONNECTION ESTABLISHMENT
This function makes a non-blocking accept on a port and polls every second until
MAX_ACCEPT_POLL is reached.
*/
PUBLIC int HTDoAccept PARAMS((HTNetInfo *net));
/*
Caching Hosts Names
This part of the HTTCP module maintains a cache of all visited hosts so that subsequent
connects to the same host doesn't imply a new request to the DNS every time.
Multihomed hosts are treated specially in that the time spend on every connect is
measured and kept in the cache. On the next request to the same host, the IP-address
with the lowest average connect time is chosen. If one IP-address fails completely,
e.g. connection refused then it disabled and HTDoConnect tries one of the other
IP-addresses to the same host.
If the connect fails in the case of at single-homed host then the entry is removed from
the cache and HTDoConnect tries again asking the DNS.
RECALCULATING THE TIME-WEIGHTS ON MULTIHOMED HOSTS
On every connect to a multihomed host, the average connect time is updated
exponentially for all the entries.
*/
PUBLIC void HTTCPAddrWeights PARAMS((char * host, time_t deltatime));
/*
CONTROL VARIABLES
This parameter determines the maximum number of hosts in the cache. The default number
is 500.
*/
extern unsigned int HTConCacheSize;
/*
Errors and status indications
Theese functions return an explanation if an error has occured.
ERRNO MESSAGE
Return error message corresponding to current errno, just like strerror().
*/
PUBLIC CONST char * HTErrnoString NOPARAMS;
/*
DESCRIPTION OF WHAT CAUSED THE ERROR
The parameter `where' gives a description of what caused the error, often the name of a
system call.
This function should only rarely be called directly. Instead the common error function
HTErrorAdd() should be used as then the error is parsed all the way to the user. The
function returns a negative status in the unix way.
*/
PUBLIC int HTInetStatus PARAMS((char * where));
/*
PARSE A CARDINAL VALUE
*/
/* Parse a cardinal value parse_cardinal()
** ----------------------
**
** On entry:
** *pp points to first character to be interpreted, terminated by
** non 0..9 character.
** *pstatus points to status already valid,
** maxvalue gives the largest allowable value.
**
** On exit:
** *pp points to first unread character,
** *pstatus points to status updated iff bad
*/
PUBLIC unsigned int HTCardinal PARAMS((int * pstatus,
char ** pp,
unsigned int max_value));
/*
Internet Name Server Functions
The following functions are available to get information about a specified host.
PRODUCE A STRING FOR AN INTERNET ADDRESS
This function is equivalent to the BSD system call inet_ntoa in that it converts a
numeric 32-bit IP-address to a dotted-notation decimal string. The pointer returned
points to static memory which must be copied if it is to be kept.
*/
PUBLIC CONST char * HTInetString PARAMS((struct sockaddr_in * sin));
/*
PARSE AN INTERNET NODE ADDRESS AND PORT
This function finds the address of a specified host and fills out the sockaddr
structure. str points to a string with a node name or number, with optional trailing
colon and port number. sin points to the binary internet or decnet address field.
On exit *sin is filled in. If no port is specified in str, that field is left unchanged
in *sin. On success, the number of homes on the host is returned.
*/
PUBLIC int HTParseInet PARAMS(( struct sockaddr_in * sin,
CONST char * str,
BOOL use_cur));
/*
NAME OF A MACHINE ON THE OTHER SIDE OF A SOCKET
This function should have been called HTGetHostByAddr but for historical reasons this
is not the case.
Note:This function used to be called HTGetHostName but this is now used to find you own
host name, see HTGetHostName()
*/
PUBLIC char * HTGetHostBySock PARAMS((int soc));
/*
HOST ADDRESS RETUNED FOR SPECIFIED HOST NAME
This function gets the address of the host and puts it in to the socket structure. It
maintains its own cache of connections so that the communication to the Domain Name
Server is minimized. If OK and single homed host then it returns 0 but if it is a
multi-homed host then 1 is returned.
*/
PUBLIC int HTGetHostByName PARAMS((char *host, SockA *sin, BOOL use_cur));
/*
GET NAME OF THIS MACHINE
This function returns a CONET char pointer to a static location containing the name of
this host or NULL if not available.
*/
PUBLIC CONST char * HTGetHostName NOPARAMS;
/*
SET NAME OF THIS MACHINE
This function overwrites any other value of current host name. This might be set by the
user to change the value in the ID value parsed to a news host when posting. The change
doesn't influence the Mail Address as they are stored in two different locations. If,
however, the change is done before the first call to HTGetMailAddress() then this
function will use the new host and domain name.
*/
PUBLIC void HTSetHostName PARAMS((char * host));
/*
GET DOMAIN NAME OF THIS MACHINE
This function rerturns the domain name part of the host name as returned by
HTGetHostName() function. Changing the domain name requires a call to HTSetHostname().
*/
PUBLIC CONST char *HTGetDomainName NOPARAMS;
/*
GET USER MAIL ADDRESS
This functions returns a char pointer to a static location containing the mail address
of the current user. The static location is different from the one of the current host
name so different values can be assigned. The default value is <USER>@hostname where
hostname is as returned by HTGetHostName().
*/
PUBLIC CONST char * HTGetMailAddress NOPARAMS;
/*
SET USER MAIL ADDRESS
This function overwrites any other value of current mail address. This might be set by
the user to change the value in the From field in the HTTP Protocol.
*/
PUBLIC void HTSetMailAddress PARAMS((char * address));
/*
*/
#endif /* HTTCP_H */
/*
End of file */
|
