Contents of /trunk/mkinitrd-magellan/busybox/networking/tcpudp.c
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Wed Aug 18 21:56:57 2010 UTC (14 years, 1 month ago) by niro
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Wed Aug 18 21:56:57 2010 UTC (14 years, 1 month ago) by niro
File MIME type: text/plain
File size: 18630 byte(s)
-updated to busybox-1.17.1
1 | /* Based on ipsvd utilities written by Gerrit Pape <pape@smarden.org> |
2 | * which are released into public domain by the author. |
3 | * Homepage: http://smarden.sunsite.dk/ipsvd/ |
4 | * |
5 | * Copyright (C) 2007 Denys Vlasenko. |
6 | * |
7 | * Licensed under GPLv2, see file LICENSE in this tarball for details. |
8 | */ |
9 | |
10 | /* Based on ipsvd-0.12.1. This tcpsvd accepts all options |
11 | * which are supported by one from ipsvd-0.12.1, but not all are |
12 | * functional. See help text at the end of this file for details. |
13 | * |
14 | * Code inside "#ifdef SSLSVD" is for sslsvd and is currently unused. |
15 | * |
16 | * Busybox version exports TCPLOCALADDR instead of |
17 | * TCPLOCALIP + TCPLOCALPORT pair. ADDR more closely matches reality |
18 | * (which is "struct sockaddr_XXX". Port is not a separate entity, |
19 | * it's just a part of (AF_INET[6]) sockaddr!). |
20 | * |
21 | * TCPORIGDSTADDR is Busybox-specific addition. |
22 | * |
23 | * udp server is hacked up by reusing TCP code. It has the following |
24 | * limitation inherent in Unix DGRAM sockets implementation: |
25 | * - local IP address is retrieved (using recvmsg voodoo) but |
26 | * child's socket is not bound to it (bind cannot be called on |
27 | * already bound socket). Thus it still can emit outgoing packets |
28 | * with wrong source IP... |
29 | * - don't know how to retrieve ORIGDST for udp. |
30 | */ |
31 | |
32 | #include "libbb.h" |
33 | /* Wants <limits.h> etc, thus included after libbb.h: */ |
34 | #include <linux/types.h> /* for __be32 etc */ |
35 | #include <linux/netfilter_ipv4.h> |
36 | |
37 | // TODO: move into this file: |
38 | #include "tcpudp_perhost.h" |
39 | |
40 | #ifdef SSLSVD |
41 | #include "matrixSsl.h" |
42 | #include "ssl_io.h" |
43 | #endif |
44 | |
45 | struct globals { |
46 | unsigned verbose; |
47 | unsigned max_per_host; |
48 | unsigned cur_per_host; |
49 | unsigned cnum; |
50 | unsigned cmax; |
51 | char **env_cur; |
52 | char *env_var[1]; /* actually bigger */ |
53 | } FIX_ALIASING; |
54 | #define G (*(struct globals*)&bb_common_bufsiz1) |
55 | #define verbose (G.verbose ) |
56 | #define max_per_host (G.max_per_host) |
57 | #define cur_per_host (G.cur_per_host) |
58 | #define cnum (G.cnum ) |
59 | #define cmax (G.cmax ) |
60 | #define env_cur (G.env_cur ) |
61 | #define env_var (G.env_var ) |
62 | #define INIT_G() do { \ |
63 | cmax = 30; \ |
64 | env_cur = &env_var[0]; \ |
65 | } while (0) |
66 | |
67 | |
68 | /* We have to be careful about leaking memory in repeated setenv's */ |
69 | static void xsetenv_plain(const char *n, const char *v) |
70 | { |
71 | char *var = xasprintf("%s=%s", n, v); |
72 | *env_cur++ = var; |
73 | putenv(var); |
74 | } |
75 | |
76 | static void xsetenv_proto(const char *proto, const char *n, const char *v) |
77 | { |
78 | char *var = xasprintf("%s%s=%s", proto, n, v); |
79 | *env_cur++ = var; |
80 | putenv(var); |
81 | } |
82 | |
83 | static void undo_xsetenv(void) |
84 | { |
85 | char **pp = env_cur = &env_var[0]; |
86 | while (*pp) { |
87 | char *var = *pp; |
88 | bb_unsetenv_and_free(var); |
89 | *pp++ = NULL; |
90 | } |
91 | } |
92 | |
93 | static void sig_term_handler(int sig) |
94 | { |
95 | if (verbose) |
96 | bb_error_msg("got signal %u, exit", sig); |
97 | kill_myself_with_sig(sig); |
98 | } |
99 | |
100 | /* Little bloated, but tries to give accurate info how child exited. |
101 | * Makes easier to spot segfaulting children etc... */ |
102 | static void print_waitstat(unsigned pid, int wstat) |
103 | { |
104 | unsigned e = 0; |
105 | const char *cause = "?exit"; |
106 | |
107 | if (WIFEXITED(wstat)) { |
108 | cause++; |
109 | e = WEXITSTATUS(wstat); |
110 | } else if (WIFSIGNALED(wstat)) { |
111 | cause = "signal"; |
112 | e = WTERMSIG(wstat); |
113 | } |
114 | bb_error_msg("end %d %s %d", pid, cause, e); |
115 | } |
116 | |
117 | /* Must match getopt32 in main! */ |
118 | enum { |
119 | OPT_c = (1 << 0), |
120 | OPT_C = (1 << 1), |
121 | OPT_i = (1 << 2), |
122 | OPT_x = (1 << 3), |
123 | OPT_u = (1 << 4), |
124 | OPT_l = (1 << 5), |
125 | OPT_E = (1 << 6), |
126 | OPT_b = (1 << 7), |
127 | OPT_h = (1 << 8), |
128 | OPT_p = (1 << 9), |
129 | OPT_t = (1 << 10), |
130 | OPT_v = (1 << 11), |
131 | OPT_V = (1 << 12), |
132 | OPT_U = (1 << 13), /* from here: sslsvd only */ |
133 | OPT_slash = (1 << 14), |
134 | OPT_Z = (1 << 15), |
135 | OPT_K = (1 << 16), |
136 | }; |
137 | |
138 | static void connection_status(void) |
139 | { |
140 | /* "only 1 client max" desn't need this */ |
141 | if (cmax > 1) |
142 | bb_error_msg("status %u/%u", cnum, cmax); |
143 | } |
144 | |
145 | static void sig_child_handler(int sig UNUSED_PARAM) |
146 | { |
147 | int wstat; |
148 | pid_t pid; |
149 | |
150 | while ((pid = wait_any_nohang(&wstat)) > 0) { |
151 | if (max_per_host) |
152 | ipsvd_perhost_remove(pid); |
153 | if (cnum) |
154 | cnum--; |
155 | if (verbose) |
156 | print_waitstat(pid, wstat); |
157 | } |
158 | if (verbose) |
159 | connection_status(); |
160 | } |
161 | |
162 | int tcpudpsvd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
163 | int tcpudpsvd_main(int argc UNUSED_PARAM, char **argv) |
164 | { |
165 | char *str_C, *str_t; |
166 | char *user; |
167 | struct hcc *hccp; |
168 | const char *instructs; |
169 | char *msg_per_host = NULL; |
170 | unsigned len_per_host = len_per_host; /* gcc */ |
171 | #ifndef SSLSVD |
172 | struct bb_uidgid_t ugid; |
173 | #endif |
174 | bool tcp; |
175 | uint16_t local_port; |
176 | char *preset_local_hostname = NULL; |
177 | char *remote_hostname = remote_hostname; /* for compiler */ |
178 | char *remote_addr = remote_addr; /* for compiler */ |
179 | len_and_sockaddr *lsa; |
180 | len_and_sockaddr local, remote; |
181 | socklen_t sa_len; |
182 | int pid; |
183 | int sock; |
184 | int conn; |
185 | unsigned backlog = 20; |
186 | unsigned opts; |
187 | |
188 | INIT_G(); |
189 | |
190 | tcp = (applet_name[0] == 't'); |
191 | |
192 | /* 3+ args, -i at most once, -p implies -h, -v is counter, -b N, -c N */ |
193 | opt_complementary = "-3:i--i:ph:vv:b+:c+"; |
194 | #ifdef SSLSVD |
195 | opts = getopt32(argv, "+c:C:i:x:u:l:Eb:hpt:vU:/:Z:K:", |
196 | &cmax, &str_C, &instructs, &instructs, &user, &preset_local_hostname, |
197 | &backlog, &str_t, &ssluser, &root, &cert, &key, &verbose |
198 | ); |
199 | #else |
200 | /* "+": stop on first non-option */ |
201 | opts = getopt32(argv, "+c:C:i:x:u:l:Eb:hpt:v", |
202 | &cmax, &str_C, &instructs, &instructs, &user, &preset_local_hostname, |
203 | &backlog, &str_t, &verbose |
204 | ); |
205 | #endif |
206 | if (opts & OPT_C) { /* -C n[:message] */ |
207 | max_per_host = bb_strtou(str_C, &str_C, 10); |
208 | if (str_C[0]) { |
209 | if (str_C[0] != ':') |
210 | bb_show_usage(); |
211 | msg_per_host = str_C + 1; |
212 | len_per_host = strlen(msg_per_host); |
213 | } |
214 | } |
215 | if (max_per_host > cmax) |
216 | max_per_host = cmax; |
217 | if (opts & OPT_u) { |
218 | xget_uidgid(&ugid, user); |
219 | } |
220 | #ifdef SSLSVD |
221 | if (opts & OPT_U) ssluser = optarg; |
222 | if (opts & OPT_slash) root = optarg; |
223 | if (opts & OPT_Z) cert = optarg; |
224 | if (opts & OPT_K) key = optarg; |
225 | #endif |
226 | argv += optind; |
227 | if (!argv[0][0] || LONE_CHAR(argv[0], '0')) |
228 | argv[0] = (char*)"0.0.0.0"; |
229 | |
230 | /* Per-IP flood protection is not thought-out for UDP */ |
231 | if (!tcp) |
232 | max_per_host = 0; |
233 | |
234 | bb_sanitize_stdio(); /* fd# 0,1,2 must be opened */ |
235 | |
236 | #ifdef SSLSVD |
237 | sslser = user; |
238 | client = 0; |
239 | if ((getuid() == 0) && !(opts & OPT_u)) { |
240 | xfunc_exitcode = 100; |
241 | bb_error_msg_and_die(bb_msg_you_must_be_root); |
242 | } |
243 | if (opts & OPT_u) |
244 | if (!uidgid_get(&sslugid, ssluser, 1)) { |
245 | if (errno) { |
246 | bb_perror_msg_and_die("can't get user/group: %s", ssluser); |
247 | } |
248 | bb_error_msg_and_die("unknown user/group %s", ssluser); |
249 | } |
250 | if (!cert) cert = "./cert.pem"; |
251 | if (!key) key = cert; |
252 | if (matrixSslOpen() < 0) |
253 | fatal("can't initialize ssl"); |
254 | if (matrixSslReadKeys(&keys, cert, key, 0, ca) < 0) { |
255 | if (client) |
256 | fatal("can't read cert, key, or ca file"); |
257 | fatal("can't read cert or key file"); |
258 | } |
259 | if (matrixSslNewSession(&ssl, keys, 0, SSL_FLAGS_SERVER) < 0) |
260 | fatal("can't create ssl session"); |
261 | #endif |
262 | |
263 | sig_block(SIGCHLD); |
264 | signal(SIGCHLD, sig_child_handler); |
265 | bb_signals(BB_FATAL_SIGS, sig_term_handler); |
266 | signal(SIGPIPE, SIG_IGN); |
267 | |
268 | if (max_per_host) |
269 | ipsvd_perhost_init(cmax); |
270 | |
271 | local_port = bb_lookup_port(argv[1], tcp ? "tcp" : "udp", 0); |
272 | lsa = xhost2sockaddr(argv[0], local_port); |
273 | argv += 2; |
274 | |
275 | sock = xsocket(lsa->u.sa.sa_family, tcp ? SOCK_STREAM : SOCK_DGRAM, 0); |
276 | setsockopt_reuseaddr(sock); |
277 | sa_len = lsa->len; /* I presume sockaddr len stays the same */ |
278 | xbind(sock, &lsa->u.sa, sa_len); |
279 | if (tcp) { |
280 | xlisten(sock, backlog); |
281 | close_on_exec_on(sock); |
282 | } else { /* udp: needed for recv_from_to to work: */ |
283 | socket_want_pktinfo(sock); |
284 | } |
285 | /* ndelay_off(sock); - it is the default I think? */ |
286 | |
287 | #ifndef SSLSVD |
288 | if (opts & OPT_u) { |
289 | /* drop permissions */ |
290 | xsetgid(ugid.gid); |
291 | xsetuid(ugid.uid); |
292 | } |
293 | #endif |
294 | |
295 | if (verbose) { |
296 | char *addr = xmalloc_sockaddr2dotted(&lsa->u.sa); |
297 | if (opts & OPT_u) |
298 | bb_error_msg("listening on %s, starting, uid %u, gid %u", addr, |
299 | (unsigned)ugid.uid, (unsigned)ugid.gid); |
300 | else |
301 | bb_error_msg("listening on %s, starting", addr); |
302 | free(addr); |
303 | } |
304 | |
305 | /* Main accept() loop */ |
306 | |
307 | again: |
308 | hccp = NULL; |
309 | |
310 | while (cnum >= cmax) |
311 | wait_for_any_sig(); /* expecting SIGCHLD */ |
312 | |
313 | /* Accept a connection to fd #0 */ |
314 | again1: |
315 | close(0); |
316 | again2: |
317 | sig_unblock(SIGCHLD); |
318 | local.len = remote.len = sa_len; |
319 | if (tcp) { |
320 | conn = accept(sock, &remote.u.sa, &remote.len); |
321 | } else { |
322 | /* In case recv_from_to won't be able to recover local addr. |
323 | * Also sets port - recv_from_to is unable to do it. */ |
324 | local = *lsa; |
325 | conn = recv_from_to(sock, NULL, 0, MSG_PEEK, |
326 | &remote.u.sa, &local.u.sa, sa_len); |
327 | } |
328 | sig_block(SIGCHLD); |
329 | if (conn < 0) { |
330 | if (errno != EINTR) |
331 | bb_perror_msg(tcp ? "accept" : "recv"); |
332 | goto again2; |
333 | } |
334 | xmove_fd(tcp ? conn : sock, 0); |
335 | |
336 | if (max_per_host) { |
337 | /* Drop connection immediately if cur_per_host > max_per_host |
338 | * (minimizing load under SYN flood) */ |
339 | remote_addr = xmalloc_sockaddr2dotted_noport(&remote.u.sa); |
340 | cur_per_host = ipsvd_perhost_add(remote_addr, max_per_host, &hccp); |
341 | if (cur_per_host > max_per_host) { |
342 | /* ipsvd_perhost_add detected that max is exceeded |
343 | * (and did not store ip in connection table) */ |
344 | free(remote_addr); |
345 | if (msg_per_host) { |
346 | /* don't block or test for errors */ |
347 | send(0, msg_per_host, len_per_host, MSG_DONTWAIT); |
348 | } |
349 | goto again1; |
350 | } |
351 | /* NB: remote_addr is not leaked, it is stored in conn table */ |
352 | } |
353 | |
354 | if (!tcp) { |
355 | /* Voodoo magic: making udp sockets each receive its own |
356 | * packets is not trivial, and I still not sure |
357 | * I do it 100% right. |
358 | * 1) we have to do it before fork() |
359 | * 2) order is important - is it right now? */ |
360 | |
361 | /* Open new non-connected UDP socket for further clients... */ |
362 | sock = xsocket(lsa->u.sa.sa_family, SOCK_DGRAM, 0); |
363 | setsockopt_reuseaddr(sock); |
364 | /* Make plain write/send work for old socket by supplying default |
365 | * destination address. This also restricts incoming packets |
366 | * to ones coming from this remote IP. */ |
367 | xconnect(0, &remote.u.sa, sa_len); |
368 | /* hole? at this point we have no wildcard udp socket... |
369 | * can this cause clients to get "port unreachable" icmp? |
370 | * Yup, time window is very small, but it exists (is it?) */ |
371 | /* ..."open new socket", continued */ |
372 | xbind(sock, &lsa->u.sa, sa_len); |
373 | socket_want_pktinfo(sock); |
374 | |
375 | /* Doesn't work: |
376 | * we cannot replace fd #0 - we will lose pending packet |
377 | * which is already buffered for us! And we cannot use fd #1 |
378 | * instead - it will "intercept" all following packets, but child |
379 | * does not expect data coming *from fd #1*! */ |
380 | #if 0 |
381 | /* Make it so that local addr is fixed to localp->u.sa |
382 | * and we don't accidentally accept packets to other local IPs. */ |
383 | /* NB: we possibly bind to the _very_ same_ address & port as the one |
384 | * already bound in parent! This seems to work in Linux. |
385 | * (otherwise we can move socket to fd #0 only if bind succeeds) */ |
386 | close(0); |
387 | set_nport(localp, htons(local_port)); |
388 | xmove_fd(xsocket(localp->u.sa.sa_family, SOCK_DGRAM, 0), 0); |
389 | setsockopt_reuseaddr(0); /* crucial */ |
390 | xbind(0, &localp->u.sa, localp->len); |
391 | #endif |
392 | } |
393 | |
394 | pid = vfork(); |
395 | if (pid == -1) { |
396 | bb_perror_msg("vfork"); |
397 | goto again; |
398 | } |
399 | |
400 | if (pid != 0) { |
401 | /* Parent */ |
402 | cnum++; |
403 | if (verbose) |
404 | connection_status(); |
405 | if (hccp) |
406 | hccp->pid = pid; |
407 | /* clean up changes done by vforked child */ |
408 | undo_xsetenv(); |
409 | goto again; |
410 | } |
411 | |
412 | /* Child: prepare env, log, and exec prog */ |
413 | |
414 | { /* vfork alert! every xmalloc in this block should be freed! */ |
415 | char *local_hostname = local_hostname; /* for compiler */ |
416 | char *local_addr = NULL; |
417 | char *free_me0 = NULL; |
418 | char *free_me1 = NULL; |
419 | char *free_me2 = NULL; |
420 | |
421 | if (verbose || !(opts & OPT_E)) { |
422 | if (!max_per_host) /* remote_addr is not yet known */ |
423 | free_me0 = remote_addr = xmalloc_sockaddr2dotted(&remote.u.sa); |
424 | if (opts & OPT_h) { |
425 | free_me1 = remote_hostname = xmalloc_sockaddr2host_noport(&remote.u.sa); |
426 | if (!remote_hostname) { |
427 | bb_error_msg("can't look up hostname for %s", remote_addr); |
428 | remote_hostname = remote_addr; |
429 | } |
430 | } |
431 | /* Find out local IP peer connected to. |
432 | * Errors ignored (I'm not paranoid enough to imagine kernel |
433 | * which doesn't know local IP). */ |
434 | if (tcp) |
435 | getsockname(0, &local.u.sa, &local.len); |
436 | /* else: for UDP it is done earlier by parent */ |
437 | local_addr = xmalloc_sockaddr2dotted(&local.u.sa); |
438 | if (opts & OPT_h) { |
439 | local_hostname = preset_local_hostname; |
440 | if (!local_hostname) { |
441 | free_me2 = local_hostname = xmalloc_sockaddr2host_noport(&local.u.sa); |
442 | if (!local_hostname) |
443 | bb_error_msg_and_die("can't look up hostname for %s", local_addr); |
444 | } |
445 | /* else: local_hostname is not NULL, but is NOT malloced! */ |
446 | } |
447 | } |
448 | if (verbose) { |
449 | pid = getpid(); |
450 | if (max_per_host) { |
451 | bb_error_msg("concurrency %s %u/%u", |
452 | remote_addr, |
453 | cur_per_host, max_per_host); |
454 | } |
455 | bb_error_msg((opts & OPT_h) |
456 | ? "start %u %s-%s (%s-%s)" |
457 | : "start %u %s-%s", |
458 | pid, |
459 | local_addr, remote_addr, |
460 | local_hostname, remote_hostname); |
461 | } |
462 | |
463 | if (!(opts & OPT_E)) { |
464 | /* setup ucspi env */ |
465 | const char *proto = tcp ? "TCP" : "UDP"; |
466 | |
467 | /* Extract "original" destination addr:port |
468 | * from Linux firewall. Useful when you redirect |
469 | * an outbond connection to local handler, and it needs |
470 | * to know where it originally tried to connect */ |
471 | if (tcp && getsockopt(0, SOL_IP, SO_ORIGINAL_DST, &local.u.sa, &local.len) == 0) { |
472 | char *addr = xmalloc_sockaddr2dotted(&local.u.sa); |
473 | xsetenv_plain("TCPORIGDSTADDR", addr); |
474 | free(addr); |
475 | } |
476 | xsetenv_plain("PROTO", proto); |
477 | xsetenv_proto(proto, "LOCALADDR", local_addr); |
478 | xsetenv_proto(proto, "REMOTEADDR", remote_addr); |
479 | if (opts & OPT_h) { |
480 | xsetenv_proto(proto, "LOCALHOST", local_hostname); |
481 | xsetenv_proto(proto, "REMOTEHOST", remote_hostname); |
482 | } |
483 | //compat? xsetenv_proto(proto, "REMOTEINFO", ""); |
484 | /* additional */ |
485 | if (cur_per_host > 0) /* can not be true for udp */ |
486 | xsetenv_plain("TCPCONCURRENCY", utoa(cur_per_host)); |
487 | } |
488 | free(local_addr); |
489 | free(free_me0); |
490 | free(free_me1); |
491 | free(free_me2); |
492 | } |
493 | |
494 | xdup2(0, 1); |
495 | |
496 | signal(SIGPIPE, SIG_DFL); /* this one was SIG_IGNed */ |
497 | /* Non-ignored signals revert to SIG_DFL on exec anyway */ |
498 | /*signal(SIGCHLD, SIG_DFL);*/ |
499 | sig_unblock(SIGCHLD); |
500 | |
501 | #ifdef SSLSVD |
502 | strcpy(id, utoa(pid)); |
503 | ssl_io(0, argv); |
504 | bb_perror_msg_and_die("can't execute '%s'", argv[0]); |
505 | #else |
506 | BB_EXECVP_or_die(argv); |
507 | #endif |
508 | } |
509 | |
510 | /* |
511 | tcpsvd [-hpEvv] [-c n] [-C n:msg] [-b n] [-u user] [-l name] |
512 | [-i dir|-x cdb] [ -t sec] host port prog |
513 | |
514 | tcpsvd creates a TCP/IP socket, binds it to the address host:port, |
515 | and listens on the socket for incoming connections. |
516 | |
517 | On each incoming connection, tcpsvd conditionally runs a program, |
518 | with standard input reading from the socket, and standard output |
519 | writing to the socket, to handle this connection. tcpsvd keeps |
520 | listening on the socket for new connections, and can handle |
521 | multiple connections simultaneously. |
522 | |
523 | tcpsvd optionally checks for special instructions depending |
524 | on the IP address or hostname of the client that initiated |
525 | the connection, see ipsvd-instruct(5). |
526 | |
527 | host |
528 | host either is a hostname, or a dotted-decimal IP address, |
529 | or 0. If host is 0, tcpsvd accepts connections to any local |
530 | IP address. |
531 | * busybox accepts IPv6 addresses and host:port pairs too |
532 | In this case second parameter is ignored |
533 | port |
534 | tcpsvd accepts connections to host:port. port may be a name |
535 | from /etc/services or a number. |
536 | prog |
537 | prog consists of one or more arguments. For each connection, |
538 | tcpsvd normally runs prog, with file descriptor 0 reading from |
539 | the network, and file descriptor 1 writing to the network. |
540 | By default it also sets up TCP-related environment variables, |
541 | see tcp-environ(5) |
542 | -i dir |
543 | read instructions for handling new connections from the instructions |
544 | directory dir. See ipsvd-instruct(5) for details. |
545 | * ignored by busyboxed version |
546 | -x cdb |
547 | read instructions for handling new connections from the constant database |
548 | cdb. The constant database normally is created from an instructions |
549 | directory by running ipsvd-cdb(8). |
550 | * ignored by busyboxed version |
551 | -t sec |
552 | timeout. This option only takes effect if the -i option is given. |
553 | While checking the instructions directory, check the time of last access |
554 | of the file that matches the clients address or hostname if any, discard |
555 | and remove the file if it wasn't accessed within the last sec seconds; |
556 | tcpsvd does not discard or remove a file if the user's write permission |
557 | is not set, for those files the timeout is disabled. Default is 0, |
558 | which means that the timeout is disabled. |
559 | * ignored by busyboxed version |
560 | -l name |
561 | local hostname. Do not look up the local hostname in DNS, but use name |
562 | as hostname. This option must be set if tcpsvd listens on port 53 |
563 | to avoid loops. |
564 | -u user[:group] |
565 | drop permissions. Switch user ID to user's UID, and group ID to user's |
566 | primary GID after creating and binding to the socket. If user is followed |
567 | by a colon and a group name, the group ID is switched to the GID of group |
568 | instead. All supplementary groups are removed. |
569 | -c n |
570 | concurrency. Handle up to n connections simultaneously. Default is 30. |
571 | If there are n connections active, tcpsvd defers acceptance of a new |
572 | connection until an active connection is closed. |
573 | -C n[:msg] |
574 | per host concurrency. Allow only up to n connections from the same IP |
575 | address simultaneously. If there are n active connections from one IP |
576 | address, new incoming connections from this IP address are closed |
577 | immediately. If n is followed by :msg, the message msg is written |
578 | to the client if possible, before closing the connection. By default |
579 | msg is empty. See ipsvd-instruct(5) for supported escape sequences in msg. |
580 | |
581 | For each accepted connection, the current per host concurrency is |
582 | available through the environment variable TCPCONCURRENCY. n and msg |
583 | can be overwritten by ipsvd(7) instructions, see ipsvd-instruct(5). |
584 | By default tcpsvd doesn't keep track of connections. |
585 | -h |
586 | Look up the client's hostname in DNS. |
587 | -p |
588 | paranoid. After looking up the client's hostname in DNS, look up the IP |
589 | addresses in DNS for that hostname, and forget about the hostname |
590 | if none of the addresses match the client's IP address. You should |
591 | set this option if you use hostname based instructions. The -p option |
592 | implies the -h option. |
593 | * ignored by busyboxed version |
594 | -b n |
595 | backlog. Allow a backlog of approximately n TCP SYNs. On some systems n |
596 | is silently limited. Default is 20. |
597 | -E |
598 | no special environment. Do not set up TCP-related environment variables. |
599 | -v |
600 | verbose. Print verbose messsages to standard output. |
601 | -vv |
602 | more verbose. Print more verbose messages to standard output. |
603 | * no difference between -v and -vv in busyboxed version |
604 | */ |