ref: e55cb65c247a9cdfa0528d34dec70d435898d098
dir: /sys/src/cmd/aux/trampoline.c/
#include <u.h> #include <libc.h> #include <bio.h> #include <ndb.h> #include <fcall.h> enum { Maxpath= 128, }; typedef struct Endpoints Endpoints; struct Endpoints { char *net; char *lsys; char *lserv; char *rsys; char *rserv; }; void xfer(int, int); void xfer9p(int, int); Endpoints* getendpoints(char*); char* iptomac(char*, char*); int macok(char*); int timeout; int activity; int nopts; char *opts[16]; void usage(void) { fprint(2, "usage: trampoline [-9] [-a addr] [-m netdir] [-o opt] [-t timeout] addr\n"); exits("usage"); } void main(int argc, char **argv) { char *altaddr, *checkmac, *mac; int fd, fd0, fd1, ctl, i; void (*x)(int, int); Endpoints *ep; checkmac = nil; altaddr = nil; x = xfer; ARGBEGIN{ case '9': x = xfer9p; break; case 'a': altaddr = EARGF(usage()); break; case 'm': checkmac = EARGF(usage()); break; case 't': timeout = atoi(EARGF(usage())); break; case 'o': if(nopts >= nelem(opts)) sysfatal("too many -o options"); opts[nopts++] = EARGF(usage()); break; default: usage(); }ARGEND; if(argc != 1) usage(); if(checkmac){ ep = getendpoints(checkmac); mac = iptomac(ep->rsys, ep->net); if(!macok(mac)){ syslog(0, "trampoline", "badmac %s from %s!%s for %s!%s on %s", mac, ep->rsys, ep->rserv, ep->lsys, ep->lserv, ep->net); exits("bad mac"); } } if(timeout > 0) alarm(timeout); fd0 = 0; fd1 = 1; if(altaddr){ fd0 = dial(altaddr, 0, 0, 0); if(fd0 < 0) sysfatal("dial %s: %r", altaddr); fd1 = fd0; } fd = dial(argv[0], 0, 0, &ctl); if(fd < 0) sysfatal("dial %s: %r", argv[0]); for(i = 0; i < nopts; i++){ if(write(ctl, opts[i], strlen(opts[i])) < 0) fprint(2, "%s: can't write %s: %r\n", argv0, opts[i]); } close(ctl); rfork(RFNOTEG); if(timeout > 0){ alarm(0); switch(rfork(RFPROC|RFMEM)){ case -1: fprint(2, "%s: fork: %r\n", argv0); exits("fork"); case 0: break; default: do { activity = 0; sleep(timeout); } while(activity); postnote(PNGROUP, getpid(), "timeout"); exits("timeout"); } } switch(rfork(RFPROC|RFMEM)){ case -1: fprint(2, "%s: fork: %r\n", argv0); if(timeout <= 0) exits("fork"); break; case 0: (*x)(fd0, fd); break; default: (*x)(fd, fd1); break; } postnote(PNGROUP, getpid(), "hangup"); exits(nil); } void xfer(int from, int to) { char buf[12*1024]; int n; while((n = read(from, buf, sizeof buf)) > 0){ if(write(to, buf, n) < 0) break; if(timeout > 0) activity = 1; } } void xfer9p(int from, int to) { uchar *buf; uint nbuf; int n; nbuf = 256; buf = malloc(nbuf); if(buf == nil) sysfatal("xfer: malloc %ud: %r", nbuf); for(;;){ if(readn(from, buf, 4) != 4) break; n = GBIT32(buf); if(n > nbuf){ nbuf = n+8192; buf = realloc(buf, nbuf); if(buf == nil) sysfatal("xfer: realloc %ud: %r", nbuf); } if(readn(from, buf+4, n-4) != n-4) break; if(write(to, buf, n) != n) break; if(timeout > 0) activity = 1; } } void getendpoint(char *dir, char *file, char **sysp, char **servp) { int fd, n; char buf[Maxpath]; char *sys, *serv; sys = serv = 0; snprint(buf, sizeof buf, "%s/%s", dir, file); fd = open(buf, OREAD); if(fd >= 0){ n = read(fd, buf, sizeof(buf)-1); if(n>0){ buf[n-1] = 0; serv = strchr(buf, '!'); if(serv){ *serv++ = 0; serv = strdup(serv); } sys = strdup(buf); } close(fd); } if(serv == 0) serv = strdup("unknown"); if(sys == 0) sys = strdup("unknown"); *servp = serv; *sysp = sys; } Endpoints * getendpoints(char *dir) { Endpoints *ep; char *p; ep = malloc(sizeof(*ep)); ep->net = strdup(dir); p = strchr(ep->net+1, '/'); if(p == nil){ free(ep->net); ep->net = "/net"; } else *p = 0; getendpoint(dir, "local", &ep->lsys, &ep->lserv); getendpoint(dir, "remote", &ep->rsys, &ep->rserv); return ep; } char* iptomac(char *ip, char *net) { char file[Maxpath]; Biobuf *b; char *p; char *f[5]; snprint(file, sizeof(file), "%s/arp", net); b = Bopen(file, OREAD); if(b == nil) return nil; while((p = Brdline(b, '\n')) != nil){ p[Blinelen(b)-1] = 0; if(tokenize(p, f, nelem(f)) < 4) continue; if(strcmp(f[1], "OK") == 0 && strcmp(f[2], ip) == 0){ p = strdup(f[3]); Bterm(b); return p; } } Bterm(b); return nil; } int macok(char *mac) { char *p; if(mac == nil) return 0; free(p = csgetvalue("/net", "ether", mac, "trampok", nil)); return p != nil; }