ref: e4509d40cc9759baddf1c2571247b95d2f5b61a5
dir: /sys/src/ape/lib/net/announce.c/
#include <stdlib.h> #include <sys/types.h> #include <unistd.h> #include <fcntl.h> #include <stdio.h> #include <string.h> #include <ctype.h> #include <libnet.h> #define NAMELEN 28 static int nettrans(char*, char*, int na, char*, int); /* * announce a network service. */ int announce(char *addr, char *dir) { int ctl, n, m; char buf[3*NAMELEN]; char buf2[3*NAMELEN]; char netdir[2*NAMELEN]; char naddr[3*NAMELEN]; char *cp; /* * translate the address */ if(nettrans(addr, naddr, sizeof(naddr), netdir, sizeof(netdir)) < 0) return -1; /* * get a control channel */ ctl = open(netdir, O_RDWR); if(ctl<0) return -1; cp = strrchr(netdir, '/'); *cp = 0; /* * find out which line we have */ n = sprintf(buf, "%.*s/", 2*NAMELEN+1, netdir); m = read(ctl, &buf[n], sizeof(buf)-n-1); if(n<=0){ close(ctl); return -1; } buf[n+m] = 0; /* * make the call */ n = sprintf(buf2, "announce %.*s", 2*NAMELEN, naddr); if(write(ctl, buf2, n)!=n){ close(ctl); return -1; } /* * return directory etc. */ if(dir) strcpy(dir, buf); return ctl; } /* * listen for an incoming call */ int listen(char *dir, char *newdir) { int ctl, n, m; char buf[3*NAMELEN]; char *cp; /* * open listen, wait for a call */ sprintf(buf, "%.*s/listen", 2*NAMELEN+1, dir); ctl = open(buf, O_RDWR); if(ctl < 0) return -1; /* * find out which line we have */ strcpy(buf, dir); cp = strrchr(buf, '/'); *++cp = 0; n = cp-buf; m = read(ctl, cp, sizeof(buf) - n - 1); if(n<=0){ close(ctl); return -1; } buf[n+m] = 0; /* * return directory etc. */ if(newdir) strcpy(newdir, buf); return ctl; } /* * accept a call, return an fd to the open data file */ int accept(int ctl, char *dir) { char buf[128]; char *num; long n; num = strrchr(dir, '/'); if(num == 0) num = dir; else num++; sprintf(buf, "accept %s", num); n = strlen(buf); write(ctl, buf, n); /* ignore return value, netowrk might not need accepts */ sprintf(buf, "%s/data", dir); return open(buf, O_RDWR); } /* * reject a call, tell device the reason for the rejection */ int reject(int ctl, char *dir, char *cause) { char buf[128]; char *num; long n; num = strrchr(dir, '/'); if(num == 0) num = dir; else num++; sprintf(buf, "reject %s %s", num, cause); n = strlen(buf); if(write(ctl, buf, n) != n) return -1; return 0; } /* * perform the identity translation (in case we can't reach cs) */ static int identtrans(char *addr, char *naddr, int na, char *file, int nf) { char reply[4*NAMELEN]; char *p; USED(nf); /* parse the network */ strncpy(reply, addr, sizeof(reply)); reply[sizeof(reply)-1] = 0; p = strchr(addr, '!'); if(p) *p++ = 0; sprintf(file, "/net/%.*s/clone", na - sizeof("/net//clone"), reply); strncpy(naddr, p, na); naddr[na-1] = 0; return 1; } /* * call up the connection server and get a translation */ static int nettrans(char *addr, char *naddr, int na, char *file, int nf) { int fd; char reply[4*NAMELEN]; char *cp; long n; /* * ask the connection server */ fd = open("/net/cs", O_RDWR); if(fd < 0) return identtrans(addr, naddr, na, file, nf); if(write(fd, addr, strlen(addr)) < 0){ close(fd); return -1; } lseek(fd, 0, 0); n = read(fd, reply, sizeof(reply)-1); close(fd); if(n <= 0) return -1; reply[n] = 0; /* * parse the reply */ cp = strchr(reply, ' '); if(cp == 0) return -1; *cp++ = 0; strncpy(naddr, cp, na); naddr[na-1] = 0; strncpy(file, reply, nf); file[nf-1] = 0; return 0; }