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- #include <u.h>
- #include <libc.h>
- #include <bio.h>
- #include <ip.h>
- #include <ndb.h>
- enum
- {
- Maxpath= 128,
- Maxerr= 256,
- };
- int dbg;
- int restricted;
- void sendfile(int, char*, char*);
- void recvfile(int, char*, char*);
- void nak(int, int, char*);
- void ack(int, ushort);
- void clrcon(void);
- void setuser(void);
- char* sunkernel(char*);
- void remoteaddr(char*, char*, int);
- void doserve(int);
- char bigbuf[32768];
- char raddr[64];
- char *dir = "/lib/tftpd";
- char *dirsl;
- int dirsllen;
- char flog[] = "ipboot";
- char net[Maxpath];
- enum
- {
- Tftp_READ = 1,
- Tftp_WRITE = 2,
- Tftp_DATA = 3,
- Tftp_ACK = 4,
- Tftp_ERROR = 5,
- Segsize = 512,
- };
- void
- usage(void)
- {
- fprint(2, "usage: %s [-dr] [-h homedir] [-x netmtpt]\n", argv0);
- exits("usage");
- }
- void
- main(int argc, char **argv)
- {
- char buf[64];
- char adir[64], ldir[64];
- int cfd, lcfd, dfd;
- char *p;
- setnetmtpt(net, sizeof(net), nil);
- ARGBEGIN{
- case 'd':
- dbg++;
- break;
- case 'h':
- dir = ARGF();
- break;
- case 'r':
- restricted = 1;
- break;
- case 'x':
- p = ARGF();
- if(p == nil)
- usage();
- setnetmtpt(net, sizeof(net), p);
- break;
- default:
- usage();
- }ARGEND
- snprint(buf, sizeof buf, "%s/", dir);
- dirsl = strdup(buf);
- dirsllen = strlen(dirsl);
- fmtinstall('E', eipfmt);
- fmtinstall('I', eipfmt);
- if(chdir(dir) < 0)
- sysfatal("can't get to directory %s: %r", dir);
- if(!dbg)
- switch(rfork(RFNOTEG|RFPROC|RFFDG)) {
- case -1:
- sysfatal("fork: %r");
- case 0:
- break;
- default:
- exits(0);
- }
- syslog(dbg, flog, "started");
- sprint(buf, "%s/udp!*!69", net);
- cfd = announce(buf, adir);
- setuser();
- for(;;) {
- lcfd = listen(adir, ldir);
- if(lcfd < 0)
- sysfatal("listening: %r");
- switch(fork()) {
- case -1:
- sysfatal("fork: %r");
- case 0:
- dfd = accept(cfd, ldir);
- if(dfd < 0)
- exits(0);
- remoteaddr(ldir, raddr, sizeof(raddr));
- doserve(dfd);
- exits("done");
- break;
- default:
- close(lcfd);
- continue;
- }
- }
- }
- void
- doserve(int fd)
- {
- int dlen;
- char *mode, *p;
- short op;
- dlen = read(fd, bigbuf, sizeof(bigbuf));
- if(dlen < 0)
- sysfatal("listen read: %r");
- op = (bigbuf[0]<<8) | bigbuf[1];
- dlen -= 2;
- mode = bigbuf+2;
- while(*mode != '\0' && dlen--)
- mode++;
- mode++;
- p = mode;
- while(*p && dlen--)
- p++;
- if(dlen == 0) {
- nak(fd, 0, "bad tftpmode");
- close(fd);
- syslog(dbg, flog, "bad mode %s", raddr);
- return;
- }
- if(op != Tftp_READ && op != Tftp_WRITE) {
- nak(fd, 4, "Illegal TFTP operation");
- close(fd);
- syslog(dbg, flog, "bad request %d %s", op, raddr);
- return;
- }
- if(restricted){
- if(strncmp(bigbuf+2, "../", 3) || strstr(bigbuf+2, "/../") ||
- (bigbuf[2] == '/' && strncmp(bigbuf+2, dirsl, dirsllen)!=0)){
- nak(fd, 4, "Permission denied");
- close(fd);
- syslog(dbg, flog, "bad request %d %s", op, raddr);
- return;
- }
- }
- if(op == Tftp_READ)
- sendfile(fd, bigbuf+2, mode);
- else
- recvfile(fd, bigbuf+2, mode);
- }
- void
- catcher(void *junk, char *msg)
- {
- USED(junk);
- if(strncmp(msg, "exit", 4) == 0)
- noted(NDFLT);
- noted(NCONT);
- }
- void
- sendfile(int fd, char *name, char *mode)
- {
- int file;
- uchar buf[Segsize+4];
- uchar ack[1024];
- char errbuf[Maxerr];
- int ackblock, block, ret;
- int rexmit, n, al, txtry, rxl;
- short op;
- syslog(dbg, flog, "send file '%s' %s to %s", name, mode, raddr);
- name = sunkernel(name);
- if(name == 0){
- nak(fd, 0, "not in our database");
- return;
- }
- notify(catcher);
- file = open(name, OREAD);
- if(file < 0) {
- errstr(errbuf, sizeof errbuf);
- nak(fd, 0, errbuf);
- return;
- }
- block = 0;
- rexmit = 0;
- n = 0;
- for(txtry = 0; txtry < 5;) {
- if(rexmit == 0) {
- block++;
- buf[0] = 0;
- buf[1] = Tftp_DATA;
- buf[2] = block>>8;
- buf[3] = block;
- n = read(file, buf+4, Segsize);
- if(n < 0) {
- errstr(errbuf, sizeof errbuf);
- nak(fd, 0, errbuf);
- return;
- }
- txtry = 0;
- }
- else {
- syslog(dbg, flog, "rexmit %d %s:%d to %s", 4+n, name, block, raddr);
- txtry++;
- }
- ret = write(fd, buf, 4+n);
- if(ret < 0)
- sysfatal("tftpd: network write error: %r");
- for(rxl = 0; rxl < 10; rxl++) {
- rexmit = 0;
- alarm(500);
- al = read(fd, ack, sizeof(ack));
- alarm(0);
- if(al < 0) {
- rexmit = 1;
- break;
- }
- op = ack[0]<<8|ack[1];
- if(op == Tftp_ERROR)
- goto error;
- ackblock = ack[2]<<8|ack[3];
- if(ackblock == block)
- break;
- if(ackblock == 0xffff) {
- rexmit = 1;
- break;
- }
- }
- if(ret != Segsize+4 && rexmit == 0)
- break;
- }
- error:
- close(fd);
- close(file);
- }
- void
- recvfile(int fd, char *name, char *mode)
- {
- ushort op, block, inblock;
- uchar buf[Segsize+8];
- char errbuf[Maxerr];
- int n, ret, file;
- syslog(dbg, flog, "receive file '%s' %s from %s", name, mode, raddr);
- file = create(name, OWRITE, 0666);
- if(file < 0) {
- errstr(errbuf, sizeof errbuf);
- nak(fd, 0, errbuf);
- return;
- }
- block = 0;
- ack(fd, block);
- block++;
- for(;;) {
- alarm(15000);
- n = read(fd, buf, sizeof(buf));
- alarm(0);
- if(n < 0)
- goto error;
- op = buf[0]<<8|buf[1];
- if(op == Tftp_ERROR)
- goto error;
- n -= 4;
- inblock = buf[2]<<8|buf[3];
- if(op == Tftp_DATA) {
- if(inblock == block) {
- ret = write(file, buf, n);
- if(ret < 0) {
- errstr(errbuf, sizeof errbuf);
- nak(fd, 0, errbuf);
- goto error;
- }
- ack(fd, block);
- block++;
- }
- ack(fd, 0xffff);
- }
- }
- error:
- close(file);
- }
- void
- ack(int fd, ushort block)
- {
- uchar ack[4];
- int n;
- ack[0] = 0;
- ack[1] = Tftp_ACK;
- ack[2] = block>>8;
- ack[3] = block;
- n = write(fd, ack, 4);
- if(n < 0)
- sysfatal("network write: %r");
- }
- void
- nak(int fd, int code, char *msg)
- {
- char buf[128];
- int n;
- buf[0] = 0;
- buf[1] = Tftp_ERROR;
- buf[2] = 0;
- buf[3] = code;
- strcpy(buf+4, msg);
- n = strlen(msg) + 4 + 1;
- n = write(fd, buf, n);
- if(n < 0)
- sysfatal("write nak: %r");
- }
- void
- setuser(void)
- {
- int f;
- f = open("/dev/user", OWRITE);
- if(f < 0)
- return;
- write(f, "none", sizeof("none"));
- close(f);
- }
- char*
- lookup(char *sattr, char *sval, char *tattr, char *tval)
- {
- static Ndb *db;
- char *attrs[1];
- Ndbtuple *t;
- if(db == nil)
- db = ndbopen(0);
- if(db == nil)
- return nil;
- if(sattr == nil)
- sattr = ipattr(sval);
- attrs[0] = tattr;
- t = ndbipinfo(db, sattr, sval, attrs, 1);
- if(t == nil)
- return nil;
- strcpy(tval, t->val);
- ndbfree(t);
- return tval;
- }
- /*
- * for sun kernel boots, replace the requested file name with
- * a one from our database. If the database doesn't specify a file,
- * don't answer.
- */
- char*
- sunkernel(char *name)
- {
- ulong addr;
- uchar v4[IPv4addrlen];
- uchar v6[IPaddrlen];
- char buf[Ndbvlen];
- char ipbuf[Ndbvlen];
- if(strlen(name) != 14 || strncmp(name + 8, ".SUN", 4) != 0)
- return name;
- addr = strtoul(name, 0, 16);
- v4[0] = addr>>24;
- v4[1] = addr>>16;
- v4[2] = addr>>8;
- v4[3] = addr;
- v4tov6(v6, v4);
- sprint(ipbuf, "%I", v6);
- return lookup("ip", ipbuf, "bootf", buf);
- }
- void
- remoteaddr(char *dir, char *raddr, int len)
- {
- char buf[64];
- int fd, n;
- snprint(buf, sizeof(buf), "%s/remote", dir);
- fd = open(buf, OREAD);
- if(fd < 0){
- snprint(raddr, sizeof(raddr), "unknown");
- return;
- }
- n = read(fd, raddr, len-1);
- close(fd);
- if(n <= 0){
- snprint(raddr, sizeof(raddr), "unknown");
- return;
- }
- if(n > 0)
- n--;
- raddr[n] = 0;
- }
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