Contents of /tags/mkinitrd-6_1_1/busybox/networking/nc_bloaty.c
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Mon May 4 16:31:54 2009 UTC (15 years, 4 months ago) by niro
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Mon May 4 16:31:54 2009 UTC (15 years, 4 months ago) by niro
File MIME type: text/plain
File size: 29295 byte(s)
tagged 'mkinitrd-6_1_1'
1 | /* Based on netcat 1.10 RELEASE 960320 written by hobbit@avian.org. |
2 | * Released into public domain by the author. |
3 | * |
4 | * Copyright (C) 2007 Denys Vlasenko. |
5 | * |
6 | * Licensed under GPLv2, see file LICENSE in this tarball for details. |
7 | */ |
8 | |
9 | /* Author's comments from nc 1.10: |
10 | * ===================== |
11 | * Netcat is entirely my own creation, although plenty of other code was used as |
12 | * examples. It is freely given away to the Internet community in the hope that |
13 | * it will be useful, with no restrictions except giving credit where it is due. |
14 | * No GPLs, Berkeley copyrights or any of that nonsense. The author assumes NO |
15 | * responsibility for how anyone uses it. If netcat makes you rich somehow and |
16 | * you're feeling generous, mail me a check. If you are affiliated in any way |
17 | * with Microsoft Network, get a life. Always ski in control. Comments, |
18 | * questions, and patches to hobbit@avian.org. |
19 | * ... |
20 | * Netcat and the associated package is a product of Avian Research, and is freely |
21 | * available in full source form with no restrictions save an obligation to give |
22 | * credit where due. |
23 | * ... |
24 | * A damn useful little "backend" utility begun 950915 or thereabouts, |
25 | * as *Hobbit*'s first real stab at some sockets programming. Something that |
26 | * should have and indeed may have existed ten years ago, but never became a |
27 | * standard Unix utility. IMHO, "nc" could take its place right next to cat, |
28 | * cp, rm, mv, dd, ls, and all those other cryptic and Unix-like things. |
29 | * ===================== |
30 | * |
31 | * Much of author's comments are still retained in the code. |
32 | * |
33 | * Functionality removed (rationale): |
34 | * - miltiple-port ranges, randomized port scanning (use nmap) |
35 | * - telnet support (use telnet) |
36 | * - source routing |
37 | * - multiple DNS checks |
38 | * Functionalty which is different from nc 1.10: |
39 | * - Prog in '-e prog' can have prog's parameters and options. |
40 | * Because of this -e option must be last. |
41 | * - nc doesn't redirect stderr to the network socket for the -e prog. |
42 | * - numeric addresses are printed in (), not [] (IPv6 looks better), |
43 | * port numbers are inside (): (1.2.3.4:5678) |
44 | * - network read errors are reported on verbose levels > 1 |
45 | * (nc 1.10 treats them as EOF) |
46 | * - TCP connects from wrong ip/ports (if peer ip:port is specified |
47 | * on the command line, but accept() says that it came from different addr) |
48 | * are closed, but nc doesn't exit - continues to listen/accept. |
49 | */ |
50 | |
51 | /* done in nc.c: #include "libbb.h" */ |
52 | |
53 | enum { |
54 | SLEAZE_PORT = 31337, /* for UDP-scan RTT trick, change if ya want */ |
55 | BIGSIZ = 8192, /* big buffers */ |
56 | |
57 | netfd = 3, |
58 | ofd = 4, |
59 | }; |
60 | |
61 | struct globals { |
62 | /* global cmd flags: */ |
63 | unsigned o_verbose; |
64 | unsigned o_wait; |
65 | #if ENABLE_NC_EXTRA |
66 | unsigned o_interval; |
67 | #endif |
68 | |
69 | /*int netfd;*/ |
70 | /*int ofd;*/ /* hexdump output fd */ |
71 | #if ENABLE_LFS |
72 | #define SENT_N_RECV_M "sent %llu, rcvd %llu\n" |
73 | unsigned long long wrote_out; /* total stdout bytes */ |
74 | unsigned long long wrote_net; /* total net bytes */ |
75 | #else |
76 | #define SENT_N_RECV_M "sent %u, rcvd %u\n" |
77 | unsigned wrote_out; /* total stdout bytes */ |
78 | unsigned wrote_net; /* total net bytes */ |
79 | #endif |
80 | /* ouraddr is never NULL and goes through three states as we progress: |
81 | 1 - local address before bind (IP/port possibly zero) |
82 | 2 - local address after bind (port is nonzero) |
83 | 3 - local address after connect??/recv/accept (IP and port are nonzero) */ |
84 | struct len_and_sockaddr *ouraddr; |
85 | /* themaddr is NULL if no peer hostname[:port] specified on command line */ |
86 | struct len_and_sockaddr *themaddr; |
87 | /* remend is set after connect/recv/accept to the actual ip:port of peer */ |
88 | struct len_and_sockaddr remend; |
89 | |
90 | jmp_buf jbuf; /* timer crud */ |
91 | |
92 | /* will malloc up the following globals: */ |
93 | fd_set ding1; /* for select loop */ |
94 | fd_set ding2; |
95 | char bigbuf_in[BIGSIZ]; /* data buffers */ |
96 | char bigbuf_net[BIGSIZ]; |
97 | }; |
98 | |
99 | #define G (*ptr_to_globals) |
100 | #define wrote_out (G.wrote_out ) |
101 | #define wrote_net (G.wrote_net ) |
102 | #define ouraddr (G.ouraddr ) |
103 | #define themaddr (G.themaddr ) |
104 | #define remend (G.remend ) |
105 | #define jbuf (G.jbuf ) |
106 | #define ding1 (G.ding1 ) |
107 | #define ding2 (G.ding2 ) |
108 | #define bigbuf_in (G.bigbuf_in ) |
109 | #define bigbuf_net (G.bigbuf_net) |
110 | #define o_verbose (G.o_verbose ) |
111 | #define o_wait (G.o_wait ) |
112 | #if ENABLE_NC_EXTRA |
113 | #define o_interval (G.o_interval) |
114 | #else |
115 | #define o_interval 0 |
116 | #endif |
117 | #define INIT_G() do { \ |
118 | SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \ |
119 | } while (0) |
120 | |
121 | |
122 | /* Must match getopt32 call! */ |
123 | enum { |
124 | OPT_h = (1 << 0), |
125 | OPT_n = (1 << 1), |
126 | OPT_p = (1 << 2), |
127 | OPT_s = (1 << 3), |
128 | OPT_u = (1 << 4), |
129 | OPT_v = (1 << 5), |
130 | OPT_w = (1 << 6), |
131 | OPT_l = (1 << 7) * ENABLE_NC_SERVER, |
132 | OPT_i = (1 << (7+ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA, |
133 | OPT_o = (1 << (8+ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA, |
134 | OPT_z = (1 << (9+ENABLE_NC_SERVER)) * ENABLE_NC_EXTRA, |
135 | }; |
136 | |
137 | #define o_nflag (option_mask32 & OPT_n) |
138 | #define o_udpmode (option_mask32 & OPT_u) |
139 | #if ENABLE_NC_SERVER |
140 | #define o_listen (option_mask32 & OPT_l) |
141 | #else |
142 | #define o_listen 0 |
143 | #endif |
144 | #if ENABLE_NC_EXTRA |
145 | #define o_ofile (option_mask32 & OPT_o) |
146 | #define o_zero (option_mask32 & OPT_z) |
147 | #else |
148 | #define o_ofile 0 |
149 | #define o_zero 0 |
150 | #endif |
151 | |
152 | /* Debug: squirt whatever message and sleep a bit so we can see it go by. */ |
153 | /* Beware: writes to stdOUT... */ |
154 | #if 0 |
155 | #define Debug(...) do { printf(__VA_ARGS__); printf("\n"); fflush(stdout); sleep(1); } while (0) |
156 | #else |
157 | #define Debug(...) do { } while (0) |
158 | #endif |
159 | |
160 | #define holler_error(...) do { if (o_verbose) bb_error_msg(__VA_ARGS__); } while (0) |
161 | #define holler_perror(...) do { if (o_verbose) bb_perror_msg(__VA_ARGS__); } while (0) |
162 | |
163 | /* catch: no-brainer interrupt handler */ |
164 | static void catch(int sig) |
165 | { |
166 | if (o_verbose > 1) /* normally we don't care */ |
167 | fprintf(stderr, SENT_N_RECV_M, wrote_net, wrote_out); |
168 | fprintf(stderr, "punt!\n"); |
169 | kill_myself_with_sig(sig); |
170 | } |
171 | |
172 | /* unarm */ |
173 | static void unarm(void) |
174 | { |
175 | signal(SIGALRM, SIG_IGN); |
176 | alarm(0); |
177 | } |
178 | |
179 | /* timeout and other signal handling cruft */ |
180 | static void tmtravel(int sig UNUSED_PARAM) |
181 | { |
182 | unarm(); |
183 | longjmp(jbuf, 1); |
184 | } |
185 | |
186 | /* arm: set the timer. */ |
187 | static void arm(unsigned secs) |
188 | { |
189 | signal(SIGALRM, tmtravel); |
190 | alarm(secs); |
191 | } |
192 | |
193 | /* findline: |
194 | find the next newline in a buffer; return inclusive size of that "line", |
195 | or the entire buffer size, so the caller knows how much to then write(). |
196 | Not distinguishing \n vs \r\n for the nonce; it just works as is... */ |
197 | static unsigned findline(char *buf, unsigned siz) |
198 | { |
199 | char * p; |
200 | int x; |
201 | if (!buf) /* various sanity checks... */ |
202 | return 0; |
203 | if (siz > BIGSIZ) |
204 | return 0; |
205 | x = siz; |
206 | for (p = buf; x > 0; x--) { |
207 | if (*p == '\n') { |
208 | x = (int) (p - buf); |
209 | x++; /* 'sokay if it points just past the end! */ |
210 | Debug("findline returning %d", x); |
211 | return x; |
212 | } |
213 | p++; |
214 | } /* for */ |
215 | Debug("findline returning whole thing: %d", siz); |
216 | return siz; |
217 | } /* findline */ |
218 | |
219 | /* doexec: |
220 | fiddle all the file descriptors around, and hand off to another prog. Sort |
221 | of like a one-off "poor man's inetd". This is the only section of code |
222 | that would be security-critical, which is why it's ifdefed out by default. |
223 | Use at your own hairy risk; if you leave shells lying around behind open |
224 | listening ports you deserve to lose!! */ |
225 | static int doexec(char **proggie) NORETURN; |
226 | static int doexec(char **proggie) |
227 | { |
228 | xmove_fd(netfd, 0); |
229 | dup2(0, 1); |
230 | /* dup2(0, 2); - do we *really* want this? NO! |
231 | * exec'ed prog can do it yourself, if needed */ |
232 | execvp(proggie[0], proggie); |
233 | bb_perror_msg_and_die("exec"); |
234 | } |
235 | |
236 | /* connect_w_timeout: |
237 | return an fd for one of |
238 | an open outbound TCP connection, a UDP stub-socket thingie, or |
239 | an unconnected TCP or UDP socket to listen on. |
240 | Examines various global o_blah flags to figure out what to do. |
241 | lad can be NULL, then socket is not bound to any local ip[:port] */ |
242 | static int connect_w_timeout(int fd) |
243 | { |
244 | int rr; |
245 | |
246 | /* wrap connect inside a timer, and hit it */ |
247 | arm(o_wait); |
248 | if (setjmp(jbuf) == 0) { |
249 | rr = connect(fd, &themaddr->u.sa, themaddr->len); |
250 | unarm(); |
251 | } else { /* setjmp: connect failed... */ |
252 | rr = -1; |
253 | errno = ETIMEDOUT; /* fake it */ |
254 | } |
255 | return rr; |
256 | } |
257 | |
258 | /* dolisten: |
259 | listens for |
260 | incoming and returns an open connection *from* someplace. If we were |
261 | given host/port args, any connections from elsewhere are rejected. This |
262 | in conjunction with local-address binding should limit things nicely... */ |
263 | static void dolisten(void) |
264 | { |
265 | int rr; |
266 | |
267 | if (!o_udpmode) |
268 | xlisten(netfd, 1); /* TCP: gotta listen() before we can get */ |
269 | |
270 | /* Various things that follow temporarily trash bigbuf_net, which might contain |
271 | a copy of any recvfrom()ed packet, but we'll read() another copy later. */ |
272 | |
273 | /* I can't believe I have to do all this to get my own goddamn bound address |
274 | and port number. It should just get filled in during bind() or something. |
275 | All this is only useful if we didn't say -p for listening, since if we |
276 | said -p we *know* what port we're listening on. At any rate we won't bother |
277 | with it all unless we wanted to see it, although listening quietly on a |
278 | random unknown port is probably not very useful without "netstat". */ |
279 | if (o_verbose) { |
280 | char *addr; |
281 | rr = getsockname(netfd, &ouraddr->u.sa, &ouraddr->len); |
282 | if (rr < 0) |
283 | bb_perror_msg_and_die("getsockname after bind"); |
284 | addr = xmalloc_sockaddr2dotted(&ouraddr->u.sa); |
285 | fprintf(stderr, "listening on %s ...\n", addr); |
286 | free(addr); |
287 | } |
288 | |
289 | if (o_udpmode) { |
290 | /* UDP is a speeeeecial case -- we have to do I/O *and* get the calling |
291 | party's particulars all at once, listen() and accept() don't apply. |
292 | At least in the BSD universe, however, recvfrom/PEEK is enough to tell |
293 | us something came in, and we can set things up so straight read/write |
294 | actually does work after all. Yow. YMMV on strange platforms! */ |
295 | |
296 | /* I'm not completely clear on how this works -- BSD seems to make UDP |
297 | just magically work in a connect()ed context, but we'll undoubtedly run |
298 | into systems this deal doesn't work on. For now, we apparently have to |
299 | issue a connect() on our just-tickled socket so we can write() back. |
300 | Again, why the fuck doesn't it just get filled in and taken care of?! |
301 | This hack is anything but optimal. Basically, if you want your listener |
302 | to also be able to send data back, you need this connect() line, which |
303 | also has the side effect that now anything from a different source or even a |
304 | different port on the other end won't show up and will cause ICMP errors. |
305 | I guess that's what they meant by "connect". |
306 | Let's try to remember what the "U" is *really* for, eh? */ |
307 | |
308 | /* If peer address is specified, connect to it */ |
309 | remend.len = LSA_SIZEOF_SA; |
310 | if (themaddr) { |
311 | remend = *themaddr; |
312 | xconnect(netfd, &themaddr->u.sa, themaddr->len); |
313 | } |
314 | /* peek first packet and remember peer addr */ |
315 | arm(o_wait); /* might as well timeout this, too */ |
316 | if (setjmp(jbuf) == 0) { /* do timeout for initial connect */ |
317 | /* (*ouraddr) is prefilled with "default" address */ |
318 | /* and here we block... */ |
319 | rr = recv_from_to(netfd, NULL, 0, MSG_PEEK, /*was bigbuf_net, BIGSIZ*/ |
320 | &remend.u.sa, &ouraddr->u.sa, ouraddr->len); |
321 | if (rr < 0) |
322 | bb_perror_msg_and_die("recvfrom"); |
323 | unarm(); |
324 | } else |
325 | bb_error_msg_and_die("timeout"); |
326 | /* Now we learned *to which IP* peer has connected, and we want to anchor |
327 | our socket on it, so that our outbound packets will have correct local IP. |
328 | Unfortunately, bind() on already bound socket will fail now (EINVAL): |
329 | xbind(netfd, &ouraddr->u.sa, ouraddr->len); |
330 | Need to read the packet, save data, close this socket and |
331 | create new one, and bind() it. TODO */ |
332 | if (!themaddr) |
333 | xconnect(netfd, &remend.u.sa, ouraddr->len); |
334 | } else { |
335 | /* TCP */ |
336 | arm(o_wait); /* wrap this in a timer, too; 0 = forever */ |
337 | if (setjmp(jbuf) == 0) { |
338 | again: |
339 | remend.len = LSA_SIZEOF_SA; |
340 | rr = accept(netfd, &remend.u.sa, &remend.len); |
341 | if (rr < 0) |
342 | bb_perror_msg_and_die("accept"); |
343 | if (themaddr && memcmp(&remend.u.sa, &themaddr->u.sa, remend.len) != 0) { |
344 | /* nc 1.10 bails out instead, and its error message |
345 | * is not suppressed by o_verbose */ |
346 | if (o_verbose) { |
347 | char *remaddr = xmalloc_sockaddr2dotted(&remend.u.sa); |
348 | bb_error_msg("connect from wrong ip/port %s ignored", remaddr); |
349 | free(remaddr); |
350 | } |
351 | close(rr); |
352 | goto again; |
353 | } |
354 | unarm(); |
355 | } else |
356 | bb_error_msg_and_die("timeout"); |
357 | xmove_fd(rr, netfd); /* dump the old socket, here's our new one */ |
358 | /* find out what address the connection was *to* on our end, in case we're |
359 | doing a listen-on-any on a multihomed machine. This allows one to |
360 | offer different services via different alias addresses, such as the |
361 | "virtual web site" hack. */ |
362 | rr = getsockname(netfd, &ouraddr->u.sa, &ouraddr->len); |
363 | if (rr < 0) |
364 | bb_perror_msg_and_die("getsockname after accept"); |
365 | } |
366 | |
367 | if (o_verbose) { |
368 | char *lcladdr, *remaddr, *remhostname; |
369 | |
370 | #if ENABLE_NC_EXTRA && defined(IP_OPTIONS) |
371 | /* If we can, look for any IP options. Useful for testing the receiving end of |
372 | such things, and is a good exercise in dealing with it. We do this before |
373 | the connect message, to ensure that the connect msg is uniformly the LAST |
374 | thing to emerge after all the intervening crud. Doesn't work for UDP on |
375 | any machines I've tested, but feel free to surprise me. */ |
376 | char optbuf[40]; |
377 | socklen_t x = sizeof(optbuf); |
378 | |
379 | rr = getsockopt(netfd, IPPROTO_IP, IP_OPTIONS, optbuf, &x); |
380 | if (rr < 0) |
381 | bb_perror_msg("getsockopt failed"); |
382 | else if (x) { /* we've got options, lessee em... */ |
383 | bin2hex(bigbuf_net, optbuf, x); |
384 | bigbuf_net[2*x] = '\0'; |
385 | fprintf(stderr, "IP options: %s\n", bigbuf_net); |
386 | } |
387 | #endif |
388 | |
389 | /* now check out who it is. We don't care about mismatched DNS names here, |
390 | but any ADDR and PORT we specified had better fucking well match the caller. |
391 | Converting from addr to inet_ntoa and back again is a bit of a kludge, but |
392 | gethostpoop wants a string and there's much gnarlier code out there already, |
393 | so I don't feel bad. |
394 | The *real* question is why BFD sockets wasn't designed to allow listens for |
395 | connections *from* specific hosts/ports, instead of requiring the caller to |
396 | accept the connection and then reject undesireable ones by closing. |
397 | In other words, we need a TCP MSG_PEEK. */ |
398 | /* bbox: removed most of it */ |
399 | lcladdr = xmalloc_sockaddr2dotted(&ouraddr->u.sa); |
400 | remaddr = xmalloc_sockaddr2dotted(&remend.u.sa); |
401 | remhostname = o_nflag ? remaddr : xmalloc_sockaddr2host(&remend.u.sa); |
402 | fprintf(stderr, "connect to %s from %s (%s)\n", |
403 | lcladdr, remhostname, remaddr); |
404 | free(lcladdr); |
405 | free(remaddr); |
406 | if (!o_nflag) |
407 | free(remhostname); |
408 | } |
409 | } |
410 | |
411 | /* udptest: |
412 | fire a couple of packets at a UDP target port, just to see if it's really |
413 | there. On BSD kernels, ICMP host/port-unreachable errors get delivered to |
414 | our socket as ECONNREFUSED write errors. On SV kernels, we lose; we'll have |
415 | to collect and analyze raw ICMP ourselves a la satan's probe_udp_ports |
416 | backend. Guess where one could swipe the appropriate code from... |
417 | |
418 | Use the time delay between writes if given, otherwise use the "tcp ping" |
419 | trick for getting the RTT. [I got that idea from pluvius, and warped it.] |
420 | Return either the original fd, or clean up and return -1. */ |
421 | #if ENABLE_NC_EXTRA |
422 | static int udptest(void) |
423 | { |
424 | int rr; |
425 | |
426 | rr = write(netfd, bigbuf_in, 1); |
427 | if (rr != 1) |
428 | bb_perror_msg("udptest first write"); |
429 | |
430 | if (o_wait) |
431 | sleep(o_wait); // can be interrupted! while (t) nanosleep(&t)? |
432 | else { |
433 | /* use the tcp-ping trick: try connecting to a normally refused port, which |
434 | causes us to block for the time that SYN gets there and RST gets back. |
435 | Not completely reliable, but it *does* mostly work. */ |
436 | /* Set a temporary connect timeout, so packet filtration doesnt cause |
437 | us to hang forever, and hit it */ |
438 | o_wait = 5; /* enough that we'll notice?? */ |
439 | rr = xsocket(ouraddr->u.sa.sa_family, SOCK_STREAM, 0); |
440 | set_nport(themaddr, htons(SLEAZE_PORT)); |
441 | connect_w_timeout(rr); |
442 | /* don't need to restore themaddr's port, it's not used anymore */ |
443 | close(rr); |
444 | o_wait = 0; /* restore */ |
445 | } |
446 | |
447 | rr = write(netfd, bigbuf_in, 1); |
448 | return (rr != 1); /* if rr == 1, return 0 (success) */ |
449 | } |
450 | #else |
451 | int udptest(void); |
452 | #endif |
453 | |
454 | /* oprint: |
455 | Hexdump bytes shoveled either way to a running logfile, in the format: |
456 | D offset - - - - --- 16 bytes --- - - - - # .... ascii ..... |
457 | where "which" sets the direction indicator, D: |
458 | 0 -- sent to network, or ">" |
459 | 1 -- rcvd and printed to stdout, or "<" |
460 | and "buf" and "n" are data-block and length. If the current block generates |
461 | a partial line, so be it; we *want* that lockstep indication of who sent |
462 | what when. Adapted from dgaudet's original example -- but must be ripping |
463 | *fast*, since we don't want to be too disk-bound... */ |
464 | #if ENABLE_NC_EXTRA |
465 | static void oprint(int direction, unsigned char *p, unsigned bc) |
466 | { |
467 | unsigned obc; /* current "global" offset */ |
468 | unsigned x; |
469 | unsigned char *op; /* out hexdump ptr */ |
470 | unsigned char *ap; /* out asc-dump ptr */ |
471 | unsigned char stage[100]; |
472 | |
473 | if (bc == 0) |
474 | return; |
475 | |
476 | obc = wrote_net; /* use the globals! */ |
477 | if (direction == '<') |
478 | obc = wrote_out; |
479 | stage[0] = direction; |
480 | stage[59] = '#'; /* preload separator */ |
481 | stage[60] = ' '; |
482 | |
483 | do { /* for chunk-o-data ... */ |
484 | x = 16; |
485 | if (bc < 16) { |
486 | /* memset(&stage[bc*3 + 11], ' ', 16*3 - bc*3); */ |
487 | memset(&stage[11], ' ', 16*3); |
488 | x = bc; |
489 | } |
490 | sprintf((char *)&stage[1], " %8.8x ", obc); /* xxx: still slow? */ |
491 | bc -= x; /* fix current count */ |
492 | obc += x; /* fix current offset */ |
493 | op = &stage[11]; /* where hex starts */ |
494 | ap = &stage[61]; /* where ascii starts */ |
495 | |
496 | do { /* for line of dump, however long ... */ |
497 | *op++ = 0x20 | bb_hexdigits_upcase[*p >> 4]; |
498 | *op++ = 0x20 | bb_hexdigits_upcase[*p & 0x0f]; |
499 | *op++ = ' '; |
500 | if ((*p > 31) && (*p < 127)) |
501 | *ap = *p; /* printing */ |
502 | else |
503 | *ap = '.'; /* nonprinting, loose def */ |
504 | ap++; |
505 | p++; |
506 | } while (--x); |
507 | *ap++ = '\n'; /* finish the line */ |
508 | xwrite(ofd, stage, ap - stage); |
509 | } while (bc); |
510 | } |
511 | #else |
512 | void oprint(int direction, unsigned char *p, unsigned bc); |
513 | #endif |
514 | |
515 | /* readwrite: |
516 | handle stdin/stdout/network I/O. Bwahaha!! -- the select loop from hell. |
517 | In this instance, return what might become our exit status. */ |
518 | static int readwrite(void) |
519 | { |
520 | int rr; |
521 | char *zp = zp; /* gcc */ /* stdin buf ptr */ |
522 | char *np = np; /* net-in buf ptr */ |
523 | unsigned rzleft; |
524 | unsigned rnleft; |
525 | unsigned netretry; /* net-read retry counter */ |
526 | unsigned wretry; /* net-write sanity counter */ |
527 | unsigned wfirst; /* one-shot flag to skip first net read */ |
528 | |
529 | /* if you don't have all this FD_* macro hair in sys/types.h, you'll have to |
530 | either find it or do your own bit-bashing: *ding1 |= (1 << fd), etc... */ |
531 | FD_SET(netfd, &ding1); /* global: the net is open */ |
532 | netretry = 2; |
533 | wfirst = 0; |
534 | rzleft = rnleft = 0; |
535 | if (o_interval) |
536 | sleep(o_interval); /* pause *before* sending stuff, too */ |
537 | |
538 | errno = 0; /* clear from sleep, close, whatever */ |
539 | /* and now the big ol' select shoveling loop ... */ |
540 | while (FD_ISSET(netfd, &ding1)) { /* i.e. till the *net* closes! */ |
541 | wretry = 8200; /* more than we'll ever hafta write */ |
542 | if (wfirst) { /* any saved stdin buffer? */ |
543 | wfirst = 0; /* clear flag for the duration */ |
544 | goto shovel; /* and go handle it first */ |
545 | } |
546 | ding2 = ding1; /* FD_COPY ain't portable... */ |
547 | /* some systems, notably linux, crap into their select timers on return, so |
548 | we create a expendable copy and give *that* to select. */ |
549 | if (o_wait) { |
550 | struct timeval tmp_timer; |
551 | tmp_timer.tv_sec = o_wait; |
552 | tmp_timer.tv_usec = 0; |
553 | /* highest possible fd is netfd (3) */ |
554 | rr = select(netfd+1, &ding2, NULL, NULL, &tmp_timer); |
555 | } else |
556 | rr = select(netfd+1, &ding2, NULL, NULL, NULL); |
557 | if (rr < 0 && errno != EINTR) { /* might have gotten ^Zed, etc */ |
558 | holler_perror("select"); |
559 | close(netfd); |
560 | return 1; |
561 | } |
562 | /* if we have a timeout AND stdin is closed AND we haven't heard anything |
563 | from the net during that time, assume it's dead and close it too. */ |
564 | if (rr == 0) { |
565 | if (!FD_ISSET(STDIN_FILENO, &ding1)) |
566 | netretry--; /* we actually try a coupla times. */ |
567 | if (!netretry) { |
568 | if (o_verbose > 1) /* normally we don't care */ |
569 | fprintf(stderr, "net timeout\n"); |
570 | close(netfd); |
571 | return 0; /* not an error! */ |
572 | } |
573 | } /* select timeout */ |
574 | /* xxx: should we check the exception fds too? The read fds seem to give |
575 | us the right info, and none of the examples I found bothered. */ |
576 | |
577 | /* Ding!! Something arrived, go check all the incoming hoppers, net first */ |
578 | if (FD_ISSET(netfd, &ding2)) { /* net: ding! */ |
579 | rr = read(netfd, bigbuf_net, BIGSIZ); |
580 | if (rr <= 0) { |
581 | if (rr < 0 && o_verbose > 1) { |
582 | /* nc 1.10 doesn't do this */ |
583 | bb_perror_msg("net read"); |
584 | } |
585 | FD_CLR(netfd, &ding1); /* net closed, we'll finish up... */ |
586 | rzleft = 0; /* can't write anymore: broken pipe */ |
587 | } else { |
588 | rnleft = rr; |
589 | np = bigbuf_net; |
590 | } |
591 | Debug("got %d from the net, errno %d", rr, errno); |
592 | } /* net:ding */ |
593 | |
594 | /* if we're in "slowly" mode there's probably still stuff in the stdin |
595 | buffer, so don't read unless we really need MORE INPUT! MORE INPUT! */ |
596 | if (rzleft) |
597 | goto shovel; |
598 | |
599 | /* okay, suck more stdin */ |
600 | if (FD_ISSET(STDIN_FILENO, &ding2)) { /* stdin: ding! */ |
601 | rr = read(STDIN_FILENO, bigbuf_in, BIGSIZ); |
602 | /* Considered making reads here smaller for UDP mode, but 8192-byte |
603 | mobygrams are kinda fun and exercise the reassembler. */ |
604 | if (rr <= 0) { /* at end, or fukt, or ... */ |
605 | FD_CLR(STDIN_FILENO, &ding1); /* disable and close stdin */ |
606 | close(0); |
607 | } else { |
608 | rzleft = rr; |
609 | zp = bigbuf_in; |
610 | } |
611 | } /* stdin:ding */ |
612 | shovel: |
613 | /* now that we've dingdonged all our thingdings, send off the results. |
614 | Geez, why does this look an awful lot like the big loop in "rsh"? ... |
615 | not sure if the order of this matters, but write net -> stdout first. */ |
616 | |
617 | /* sanity check. Works because they're both unsigned... */ |
618 | if ((rzleft > 8200) || (rnleft > 8200)) { |
619 | holler_error("bogus buffers: %u, %u", rzleft, rnleft); |
620 | rzleft = rnleft = 0; |
621 | } |
622 | /* net write retries sometimes happen on UDP connections */ |
623 | if (!wretry) { /* is something hung? */ |
624 | holler_error("too many output retries"); |
625 | return 1; |
626 | } |
627 | if (rnleft) { |
628 | rr = write(STDOUT_FILENO, np, rnleft); |
629 | if (rr > 0) { |
630 | if (o_ofile) /* log the stdout */ |
631 | oprint('<', (unsigned char *)np, rr); |
632 | np += rr; /* fix up ptrs and whatnot */ |
633 | rnleft -= rr; /* will get sanity-checked above */ |
634 | wrote_out += rr; /* global count */ |
635 | } |
636 | Debug("wrote %d to stdout, errno %d", rr, errno); |
637 | } /* rnleft */ |
638 | if (rzleft) { |
639 | if (o_interval) /* in "slowly" mode ?? */ |
640 | rr = findline(zp, rzleft); |
641 | else |
642 | rr = rzleft; |
643 | rr = write(netfd, zp, rr); /* one line, or the whole buffer */ |
644 | if (rr > 0) { |
645 | if (o_ofile) /* log what got sent */ |
646 | oprint('>', (unsigned char *)zp, rr); |
647 | zp += rr; |
648 | rzleft -= rr; |
649 | wrote_net += rr; /* global count */ |
650 | } |
651 | Debug("wrote %d to net, errno %d", rr, errno); |
652 | } /* rzleft */ |
653 | if (o_interval) { /* cycle between slow lines, or ... */ |
654 | sleep(o_interval); |
655 | errno = 0; /* clear from sleep */ |
656 | continue; /* ...with hairy select loop... */ |
657 | } |
658 | if ((rzleft) || (rnleft)) { /* shovel that shit till they ain't */ |
659 | wretry--; /* none left, and get another load */ |
660 | goto shovel; |
661 | } |
662 | } /* while ding1:netfd is open */ |
663 | |
664 | /* XXX: maybe want a more graceful shutdown() here, or screw around with |
665 | linger times?? I suspect that I don't need to since I'm always doing |
666 | blocking reads and writes and my own manual "last ditch" efforts to read |
667 | the net again after a timeout. I haven't seen any screwups yet, but it's |
668 | not like my test network is particularly busy... */ |
669 | close(netfd); |
670 | return 0; |
671 | } /* readwrite */ |
672 | |
673 | /* main: now we pull it all together... */ |
674 | int nc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
675 | int nc_main(int argc, char **argv) |
676 | { |
677 | char *str_p, *str_s; |
678 | USE_NC_EXTRA(char *str_i, *str_o;) |
679 | char *themdotted = themdotted; /* gcc */ |
680 | char **proggie; |
681 | int x; |
682 | unsigned o_lport = 0; |
683 | |
684 | INIT_G(); |
685 | |
686 | /* catch a signal or two for cleanup */ |
687 | bb_signals(0 |
688 | + (1 << SIGINT) |
689 | + (1 << SIGQUIT) |
690 | + (1 << SIGTERM) |
691 | , catch); |
692 | /* and suppress others... */ |
693 | bb_signals(0 |
694 | #ifdef SIGURG |
695 | + (1 << SIGURG) |
696 | #endif |
697 | + (1 << SIGPIPE) /* important! */ |
698 | , SIG_IGN); |
699 | |
700 | proggie = argv; |
701 | while (*++proggie) { |
702 | if (strcmp(*proggie, "-e") == 0) { |
703 | *proggie = NULL; |
704 | argc = proggie - argv; |
705 | proggie++; |
706 | goto e_found; |
707 | } |
708 | } |
709 | proggie = NULL; |
710 | e_found: |
711 | |
712 | // -g -G -t -r deleted, unimplemented -a deleted too |
713 | opt_complementary = "?2:vv:w+"; /* max 2 params; -v is a counter; -w N */ |
714 | getopt32(argv, "hnp:s:uvw:" USE_NC_SERVER("l") |
715 | USE_NC_EXTRA("i:o:z"), |
716 | &str_p, &str_s, &o_wait |
717 | USE_NC_EXTRA(, &str_i, &str_o, &o_verbose)); |
718 | argv += optind; |
719 | #if ENABLE_NC_EXTRA |
720 | if (option_mask32 & OPT_i) /* line-interval time */ |
721 | o_interval = xatou_range(str_i, 1, 0xffff); |
722 | #endif |
723 | //if (option_mask32 & OPT_l) /* listen mode */ |
724 | //if (option_mask32 & OPT_n) /* numeric-only, no DNS lookups */ |
725 | //if (option_mask32 & OPT_o) /* hexdump log */ |
726 | if (option_mask32 & OPT_p) { /* local source port */ |
727 | o_lport = bb_lookup_port(str_p, o_udpmode ? "udp" : "tcp", 0); |
728 | if (!o_lport) |
729 | bb_error_msg_and_die("bad local port '%s'", str_p); |
730 | } |
731 | //if (option_mask32 & OPT_r) /* randomize various things */ |
732 | //if (option_mask32 & OPT_u) /* use UDP */ |
733 | //if (option_mask32 & OPT_v) /* verbose */ |
734 | //if (option_mask32 & OPT_w) /* wait time */ |
735 | //if (option_mask32 & OPT_z) /* little or no data xfer */ |
736 | |
737 | /* We manage our fd's so that they are never 0,1,2 */ |
738 | /*bb_sanitize_stdio(); - not needed */ |
739 | |
740 | if (argv[0]) { |
741 | themaddr = xhost2sockaddr(argv[0], |
742 | argv[1] |
743 | ? bb_lookup_port(argv[1], o_udpmode ? "udp" : "tcp", 0) |
744 | : 0); |
745 | } |
746 | |
747 | /* create & bind network socket */ |
748 | x = (o_udpmode ? SOCK_DGRAM : SOCK_STREAM); |
749 | if (option_mask32 & OPT_s) { /* local address */ |
750 | /* if o_lport is still 0, then we will use random port */ |
751 | ouraddr = xhost2sockaddr(str_s, o_lport); |
752 | #ifdef BLOAT |
753 | /* prevent spurious "UDP listen needs !0 port" */ |
754 | o_lport = get_nport(ouraddr); |
755 | o_lport = ntohs(o_lport); |
756 | #endif |
757 | x = xsocket(ouraddr->u.sa.sa_family, x, 0); |
758 | } else { |
759 | /* We try IPv6, then IPv4, unless addr family is |
760 | * implicitly set by way of remote addr/port spec */ |
761 | x = xsocket_type(&ouraddr, |
762 | (themaddr ? themaddr->u.sa.sa_family : AF_UNSPEC), |
763 | x); |
764 | if (o_lport) |
765 | set_nport(ouraddr, htons(o_lport)); |
766 | } |
767 | xmove_fd(x, netfd); |
768 | setsockopt_reuseaddr(netfd); |
769 | if (o_udpmode) |
770 | socket_want_pktinfo(netfd); |
771 | xbind(netfd, &ouraddr->u.sa, ouraddr->len); |
772 | #if 0 |
773 | setsockopt(netfd, SOL_SOCKET, SO_RCVBUF, &o_rcvbuf, sizeof o_rcvbuf); |
774 | setsockopt(netfd, SOL_SOCKET, SO_SNDBUF, &o_sndbuf, sizeof o_sndbuf); |
775 | #endif |
776 | |
777 | #ifdef BLOAT |
778 | if (OPT_l && (option_mask32 & (OPT_u|OPT_l)) == (OPT_u|OPT_l)) { |
779 | /* apparently UDP can listen ON "port 0", |
780 | but that's not useful */ |
781 | if (!o_lport) |
782 | bb_error_msg_and_die("UDP listen needs nonzero -p port"); |
783 | } |
784 | #endif |
785 | |
786 | FD_SET(STDIN_FILENO, &ding1); /* stdin *is* initially open */ |
787 | if (proggie) { |
788 | close(0); /* won't need stdin */ |
789 | option_mask32 &= ~OPT_o; /* -o with -e is meaningless! */ |
790 | } |
791 | #if ENABLE_NC_EXTRA |
792 | if (o_ofile) |
793 | xmove_fd(xopen(str_o, O_WRONLY|O_CREAT|O_TRUNC), ofd); |
794 | #endif |
795 | |
796 | if (o_listen) { |
797 | dolisten(); |
798 | /* dolisten does its own connect reporting */ |
799 | if (proggie) /* -e given? */ |
800 | doexec(proggie); |
801 | x = readwrite(); /* it even works with UDP! */ |
802 | } else { |
803 | /* Outbound connects. Now we're more picky about args... */ |
804 | if (!themaddr) |
805 | bb_error_msg_and_die("no destination"); |
806 | |
807 | remend = *themaddr; |
808 | if (o_verbose) |
809 | themdotted = xmalloc_sockaddr2dotted(&themaddr->u.sa); |
810 | |
811 | x = connect_w_timeout(netfd); |
812 | if (o_zero && x == 0 && o_udpmode) /* if UDP scanning... */ |
813 | x = udptest(); |
814 | if (x == 0) { /* Yow, are we OPEN YET?! */ |
815 | if (o_verbose) |
816 | fprintf(stderr, "%s (%s) open\n", argv[0], themdotted); |
817 | if (proggie) /* exec is valid for outbound, too */ |
818 | doexec(proggie); |
819 | if (!o_zero) |
820 | x = readwrite(); |
821 | } else { /* connect or udptest wasn't successful */ |
822 | x = 1; /* exit status */ |
823 | /* if we're scanning at a "one -v" verbosity level, don't print refusals. |
824 | Give it another -v if you want to see everything. */ |
825 | if (o_verbose > 1 || (o_verbose && errno != ECONNREFUSED)) |
826 | bb_perror_msg("%s (%s)", argv[0], themdotted); |
827 | } |
828 | } |
829 | if (o_verbose > 1) /* normally we don't care */ |
830 | fprintf(stderr, SENT_N_RECV_M, wrote_net, wrote_out); |
831 | return x; |
832 | } |