Annotation of libwww/Library/src/HTTCP.html, revision 2.9
2.2 timbl 1: <HEADER>
2: <TITLE>/Net/dxcern/userd/timbl/hypertext/WWW/Library/src/HTTCP.html</TITLE></HEADER>
3: <BODY>
4: <H1>Generic TCP/IP Communication</H1>This module has the common code for
5: handling TCP/IP connections etc.
2.8 frystyk 6: <PRE>
7: #ifndef HTTCP_H
2.2 timbl 8: #define HTTCP_H
9:
2.8 frystyk 10: #include "tcp.h"
11:
2.2 timbl 12: #include "HTUtils.h"
2.8 frystyk 13: #include "HTAccess.h"
2.1 timbl 14:
15: #ifdef SHORT_NAMES
16: #define HTInetStatus HTInStat
17: #define HTInetString HTInStri
18: #define HTParseInet HTPaInet
19: #endif
2.8 frystyk 20: </PRE>
21:
22: <H2>Connection Management</H2>
23:
24: Theese functions handle access to the net.
25:
26: <H3>Active Connection Establishment</H3>
27:
28: This makes an active connect to the specified host. The request structure is
29: parsed in order to handle errors. Default port might be overwritten by any
30: port indication in the URL specified as <host>:<port> If it is
31: a multihomed host then HTDoConnect measures the time to do the connection and
32: updates the calculated weights in the cache of visited hosts.
33:
34: <PRE>
35: extern int HTDoConnect PARAMS(( HTRequest *request,
36: char *url,
37: u_short default_port,
38: int *sockfd,
39: u_long *addr));
40: </PRE>
41:
42:
43: <H3>Passive Connection Establishment</H3>
44:
45: This function makes a non-blocking accept on a port and polls every second
46: until MAX_ACCEPT_POLL or interrupted by user.
2.1 timbl 47:
2.8 frystyk 48: <PRE>
49: extern int HTDoAccept PARAMS((HTRequest *request, int sockfd));
50: </PRE>
2.1 timbl 51:
2.8 frystyk 52: <H2>Caching Hosts</H2>
53:
54: This is mainly an internal matter to the HTTCP.c module but it keeps a
55: cache of all visited hosts so that we don't have to consult the DNS every
56: time. One public function is HTTCPAddrWeights(). It updates the calculated
57: weights on the time it takes to sestablish a connection.
58:
59: <PRE>
60: extern void HTTCPAddrWeights PARAMS((char * host, time_t deltatime));
61: </PRE>
62:
2.9 ! frystyk 63: <H3>Control Variables</H3>
! 64:
! 65: This parameter determines the maximum number of hosts in the cache. If a
! 66: connect call fails, the entry is automaticly removed from the cache so that
! 67: next time we ask the DNS.
! 68:
! 69: <PRE>
! 70: extern unsigned int HTConCacheSize;
! 71: </PRE>
2.8 frystyk 72:
73: <H2>Errors and status indications</H2>
74:
75: Theese functions return an explanation if an error has occured.
76:
77: <H3>Errno Message</H3>
2.7 luotonen 78:
2.8 frystyk 79: Return error message corresponding to current errno, just like strerror().
2.7 luotonen 80:
2.8 frystyk 81: <PRE>
82: extern CONST char * HTErrnoString NOPARAMS;
83: </PRE>
2.1 timbl 84:
2.8 frystyk 85: <H3>Description of what Caused the Error</H3>
2.1 timbl 86:
2.8 frystyk 87: The parameter `where' gives a description of what caused the error, often
88: the name of a system call. <P>
2.7 luotonen 89:
2.8 frystyk 90: This function should only rarely be called directly. Instead the common error
91: function HTErrorAdd() should be used as then the error is parsed all the way
92: to the user. The function returns a negative status in the unix way.
2.1 timbl 93:
2.8 frystyk 94: <PRE>
95: extern int HTInetStatus PARAMS((char * where));
96: </PRE>
2.1 timbl 97:
2.8 frystyk 98: <PRE>
2.1 timbl 99: /* Parse a cardinal value parse_cardinal()
100: ** ----------------------
101: **
102: ** On entry:
103: ** *pp points to first character to be interpreted, terminated by
104: ** non 0..9 character.
105: ** *pstatus points to status already valid,
106: ** maxvalue gives the largest allowable value.
107: **
108: ** On exit:
109: ** *pp points to first unread character,
110: ** *pstatus points to status updated iff bad
111: */
2.2 timbl 112:
2.7 luotonen 113: PUBLIC unsigned int HTCardinal PARAMS((int * pstatus,
114: char ** pp,
115: unsigned int max_value));
2.8 frystyk 116: </PRE>
117:
118: <H2>Internet Name Server Functions</H2>
119:
120: The following functions are available to get information about a
121: specified host.
122:
123: <H3>Produce a string for an internet address</H3>
124:
125: This function is equivalent to the BSD system call <B>inet_ntoa</B> in that it
126: converts a numeric 32-bit IP-address to a dotted-notation decimal string. The
127: pointer returned points to static memory which must be copied if it is to be
128: kept.
129:
130: <PRE>
131: extern CONST char * HTInetString PARAMS((struct sockaddr_in * sin));
132: </PRE>
133:
134: <H3>Parse an internet node address and port</H3>
135:
136: This function finds the address of a specified host and fills out the sockaddr
137: structure. str points to a string with a node name or number, with optional
138: trailing colon and port number. sin points to the binary internet or decnet
139: address field. <P>
140:
141: On exit *sin is filled in. If no port is specified in str, that field is left
142: unchanged in *sin. If it is a multihomed host then multihomed is returned as
143: YES. This is used for knowing when to measure the setup time for a connection
144: in order to use the fastest IP-address on the multihomed host.
145: <PRE>
146: extern int HTParseInet PARAMS((struct sockaddr_in * sin,
147: CONST char * str,
148: BOOL * multihomed));
149: </PRE>
150:
151: <H3>Name of a Machine on the Other Side of a Socket</H3>
2.2 timbl 152:
2.8 frystyk 153: This function should have been called HTGetHostByAddr but for historical
154: reasons this is not the case.
2.1 timbl 155:
2.8 frystyk 156: <PRE>
157: extern char * HTGetHostName PARAMS((int soc));
158: </PRE>
159:
160: <H3>Host address retuned for specified host name</H3>
161:
162: This function gets the address of the host and puts it in to the socket
163: structure. It maintains its own cache of connections so that the communication
164: to the Domain Name Server is minimized. If it is a multihomed host, then
165: `multi' is set to YES.
166:
167: <PRE>
168: extern char * HTGetHostByName PARAMS((char *host, SockA *sin, BOOL *multi));
169: </PRE>
2.7 luotonen 170:
2.1 timbl 171:
2.8 frystyk 172: <H3>Get Name of This Machine</H3>
2.6 luotonen 173:
2.8 frystyk 174: This functions a char pointer to a static location containing the name of this
175: host.
2.7 luotonen 176:
2.8 frystyk 177: <PRE>
178: extern CONST char * HTHostName NOPARAMS;
179: </PRE>
2.2 timbl 180:
2.8 frystyk 181: <PRE>
2.2 timbl 182: #endif /* HTTCP_H */
2.8 frystyk 183: </PRE>
184: End of file
185: </BODY>
186: </HTML>
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