1 // delimited, authenticated, encrypted connection
2 enum{ Maxmsg=4096 };	// messages > Maxmsg bytes are truncated
3 typedef struct SConn SConn;
4 
5 extern SConn* newSConn(int);	// arg is open file descriptor
6 struct SConn{
7 	void *chan;
8 	int secretlen;
9 	int (*secret)(SConn*, uchar*, int);// 
10 	int (*read)(SConn*, uchar*, int); // <0 if error;  errmess in buffer
11 	int (*write)(SConn*, uchar*, int);
12 	void (*free)(SConn*);		// also closes file descriptor
13 };
14 // secret(s,b,dir) sets secret for digest, encrypt, using the secretlen
15 //		bytes in b to form keys 	for the two directions;
16 //	  set dir=0 in client, dir=1 in server
17 
18 // error convention: write !message in-band
19 extern void writerr(SConn*, char*);
20 extern int readstr(SConn*, char*);  // call with buf of size Maxmsg+1
21 	// returns -1 upon error, with error message in buf
22 
23 extern void *emalloc(ulong); /* dies on failure; clears memory */
24 extern void *erealloc(void *, ulong);
25 extern char *estrdup(char *);
26