223 lines
3.5 KiB
C
223 lines
3.5 KiB
C
#include <stdlib.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <string.h>
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#include <ctype.h>
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#include <libnet.h>
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#define NAMELEN 28
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static int nettrans(char*, char*, int na, char*, int);
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/*
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* announce a network service.
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*/
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int
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announce(char *addr, char *dir)
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{
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int ctl, n, m;
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char buf[3*NAMELEN];
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char buf2[3*NAMELEN];
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char netdir[2*NAMELEN];
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char naddr[3*NAMELEN];
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char *cp;
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/*
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* translate the address
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*/
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if(nettrans(addr, naddr, sizeof(naddr), netdir, sizeof(netdir)) < 0)
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return -1;
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/*
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* get a control channel
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*/
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ctl = open(netdir, O_RDWR);
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if(ctl<0)
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return -1;
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cp = strrchr(netdir, '/');
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*cp = 0;
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/*
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* find out which line we have
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*/
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n = sprintf(buf, "%.*s/", 2*NAMELEN+1, netdir);
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m = read(ctl, &buf[n], sizeof(buf)-n-1);
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if(n<=0){
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close(ctl);
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return -1;
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}
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buf[n+m] = 0;
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/*
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* make the call
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*/
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n = sprintf(buf2, "announce %.*s", 2*NAMELEN, naddr);
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if(write(ctl, buf2, n)!=n){
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close(ctl);
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return -1;
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}
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/*
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* return directory etc.
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*/
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if(dir)
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strcpy(dir, buf);
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return ctl;
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}
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/*
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* listen for an incoming call
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*/
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int
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listen(char *dir, char *newdir)
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{
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int ctl, n, m;
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char buf[3*NAMELEN];
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char *cp;
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/*
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* open listen, wait for a call
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*/
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sprintf(buf, "%.*s/listen", 2*NAMELEN+1, dir);
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ctl = open(buf, O_RDWR);
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if(ctl < 0)
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return -1;
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/*
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* find out which line we have
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*/
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strcpy(buf, dir);
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cp = strrchr(buf, '/');
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*++cp = 0;
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n = cp-buf;
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m = read(ctl, cp, sizeof(buf) - n - 1);
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if(n<=0){
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close(ctl);
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return -1;
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}
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buf[n+m] = 0;
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/*
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* return directory etc.
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*/
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if(newdir)
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strcpy(newdir, buf);
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return ctl;
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}
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/*
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* accept a call, return an fd to the open data file
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*/
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int
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accept(int ctl, char *dir)
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{
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char buf[128];
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char *num;
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long n;
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num = strrchr(dir, '/');
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if(num == 0)
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num = dir;
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else
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num++;
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sprintf(buf, "accept %s", num);
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n = strlen(buf);
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write(ctl, buf, n); /* ignore return value, netowrk might not need accepts */
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sprintf(buf, "%s/data", dir);
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return open(buf, O_RDWR);
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}
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/*
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* reject a call, tell device the reason for the rejection
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*/
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int
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reject(int ctl, char *dir, char *cause)
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{
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char buf[128];
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char *num;
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long n;
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num = strrchr(dir, '/');
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if(num == 0)
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num = dir;
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else
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num++;
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sprintf(buf, "reject %s %s", num, cause);
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n = strlen(buf);
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if(write(ctl, buf, n) != n)
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return -1;
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return 0;
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}
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/*
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* perform the identity translation (in case we can't reach cs)
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*/
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static int
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identtrans(char *addr, char *naddr, int na, char *file, int nf)
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{
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char reply[4*NAMELEN];
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char *p;
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USED(nf);
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/* parse the network */
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strncpy(reply, addr, sizeof(reply));
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reply[sizeof(reply)-1] = 0;
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p = strchr(addr, '!');
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if(p)
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*p++ = 0;
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sprintf(file, "/net/%.*s/clone", na - sizeof("/net//clone"), reply);
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strncpy(naddr, p, na);
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naddr[na-1] = 0;
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return 1;
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}
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/*
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* call up the connection server and get a translation
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*/
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static int
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nettrans(char *addr, char *naddr, int na, char *file, int nf)
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{
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int fd;
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char reply[4*NAMELEN];
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char *cp;
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long n;
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/*
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* ask the connection server
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*/
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fd = open("/net/cs", O_RDWR);
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if(fd < 0)
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return identtrans(addr, naddr, na, file, nf);
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if(write(fd, addr, strlen(addr)) < 0){
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close(fd);
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return -1;
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}
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lseek(fd, 0, 0);
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n = read(fd, reply, sizeof(reply)-1);
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close(fd);
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if(n <= 0)
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return -1;
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reply[n] = 0;
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/*
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* parse the reply
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*/
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cp = strchr(reply, ' ');
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if(cp == 0)
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return -1;
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*cp++ = 0;
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strncpy(naddr, cp, na);
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naddr[na-1] = 0;
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strncpy(file, reply, nf);
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file[nf-1] = 0;
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return 0;
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}
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