1 /* $OpenBSD: ftp-proxy.c,v 1.13 2006/12/30 13:24:00 camield Exp $ */
4 * Copyright (c) 2004, 2005 Camiel Dobbelaar, <cd@sentia.nl>
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
19 #include <sys/queue.h>
20 #include <sys/types.h>
21 #include <sys/event.h>
23 #include <sys/resource.h>
24 #include <sys/socket.h>
27 #include <net/pf/pfvar.h>
28 #include <netinet/in.h>
29 #include <arpa/inet.h>
47 #define CONNECT_TIMEOUT 30
50 #define MAX_LOGLINE 300
52 #define TCP_BACKLOG 10
54 #define CHROOT_DIR "/var/empty"
55 #define NOPRIV_USER "proxy"
57 /* pfctl standard NAT range. */
58 #define PF_NAT_PROXY_PORT_LOW 50001
59 #define PF_NAT_PROXY_PORT_HIGH 65535
61 #define sstosa(ss) ((struct sockaddr *)(ss))
63 enum { CMD_NONE = 0, CMD_PORT, CMD_EPRT, CMD_PASV, CMD_EPSV };
73 struct sockaddr_storage client_ss;
74 struct sockaddr_storage proxy_ss;
75 struct sockaddr_storage server_ss;
76 struct sockaddr_storage orig_server_ss;
88 LIST_ENTRY(session) entry;
91 LIST_HEAD(, session) sessions = LIST_HEAD_INITIALIZER(sessions);
93 void buffer_data(struct session *, struct cbuf *, char *, size_t);
94 int client_parse(struct session *);
95 int client_parse_anon(struct session *);
96 int client_parse_cmd(struct session *);
97 void client_read(struct session *);
98 void client_write(struct session *);
100 void end_session(struct session *);
101 int exit_daemon(void);
102 int getline(char *, size_t *);
103 void handle_connection(const int);
104 void handle_signal(int);
105 struct session * init_session(void);
106 void logmsg(int, const char *, ...);
107 u_int16_t parse_port(int);
108 u_int16_t pick_proxy_port(void);
109 void proxy_reply(int, struct sockaddr *, u_int16_t);
110 int server_parse(struct session *);
111 void server_read(struct session *);
112 void server_write(struct session *);
113 const char *sock_ntop(struct sockaddr *);
116 char linebuf[MAX_LINE + 1];
119 char ntop_buf[NTOP_BUFS][INET6_ADDRSTRLEN];
121 #define KQ_NEVENTS 64
122 struct kevent changes[KQ_NEVENTS];
125 struct sockaddr_storage fixed_server_ss, fixed_proxy_ss;
126 char *fixed_server, *fixed_server_port, *fixed_proxy, *listen_ip, *listen_port,
128 int anonymous_only, daemonize, id_count, ipv6_mode, loglevel, max_sessions,
129 rfc_mode, session_count, timeout, verbose;
130 extern char *__progname;
133 buffer_data(struct session *s, struct cbuf *cb, char *buf, size_t len)
138 if (cb->buffer == NULL)
139 if ((cb->buffer = malloc(MAX_LINE)) == NULL)
142 memcpy(cb->buffer, buf, len);
143 cb->buffer_size = len;
147 logmsg(LOG_ERR, "#%d could not allocate memory for buffer", s->id);
152 client_parse(struct session *s)
154 /* Reset any previous command. */
158 /* Commands we are looking for are at least 4 chars long. */
162 if (linebuf[0] == 'P' || linebuf[0] == 'p' ||
163 linebuf[0] == 'E' || linebuf[0] == 'e')
164 return (client_parse_cmd(s));
166 if (anonymous_only && (linebuf[0] == 'U' || linebuf[0] == 'u'))
167 return (client_parse_anon(s));
173 client_parse_anon(struct session *s)
177 if (strcasecmp("USER ftp\r\n", linebuf) != 0 &&
178 strcasecmp("USER anonymous\r\n", linebuf) != 0) {
179 snprintf(linebuf, sizeof linebuf,
180 "500 Only anonymous FTP allowed\r\n");
181 logmsg(LOG_DEBUG, "#%d proxy: %s", s->id, linebuf);
183 /* Talk back to the client ourself. */
184 linelen = strlen(linebuf);
185 written = write(s->client_fd, linebuf, linelen);
187 logmsg(LOG_ERR, "#%d write failed", s->id);
188 return (0); /* Session will be ended for us */
189 } else if (written < linelen) {
190 EV_SET(&changes[nchanges++], s->server_fd,
191 EVFILT_READ, EV_DISABLE, 0, 0, s);
192 EV_SET(&changes[nchanges++], s->client_fd,
193 EVFILT_WRITE, EV_ADD, 0, 0, s);
194 buffer_data(s, &s->client, linebuf + written,
199 /* Clear buffer so it's not sent to the server. */
208 client_parse_cmd(struct session *s)
210 if (strncasecmp("PASV", linebuf, 4) == 0)
212 else if (strncasecmp("PORT ", linebuf, 5) == 0)
214 else if (strncasecmp("EPSV", linebuf, 4) == 0)
216 else if (strncasecmp("EPRT ", linebuf, 5) == 0)
221 if (ipv6_mode && (s->cmd == CMD_PASV || s->cmd == CMD_PORT)) {
222 logmsg(LOG_CRIT, "PASV and PORT not allowed with IPv6");
226 if (s->cmd == CMD_PORT || s->cmd == CMD_EPRT) {
227 s->port = parse_port(s->cmd);
228 if (s->port < MIN_PORT) {
229 logmsg(LOG_CRIT, "#%d bad port in '%s'", s->id,
233 s->proxy_port = pick_proxy_port();
234 proxy_reply(s->cmd, sstosa(&s->proxy_ss), s->proxy_port);
235 logmsg(LOG_DEBUG, "#%d proxy: %s", s->id, linebuf);
242 client_read(struct session *s)
244 size_t buf_avail, bread, bwritten;
248 buf_avail = sizeof s->cbuf - s->cbuf_valid;
249 bread = read(s->client_fd, s->cbuf + s->cbuf_valid, buf_avail);
250 s->cbuf_valid += bread;
252 while ((n = getline(s->cbuf, &s->cbuf_valid)) > 0) {
253 logmsg(LOG_DEBUG, "#%d client: %s", s->id, linebuf);
254 if (!client_parse(s)) {
258 bwritten = write(s->server_fd, linebuf, linelen);
259 if (bwritten == -1) {
260 } else if (bwritten < linelen) {
261 EV_SET(&changes[nchanges++], s->client_fd,
262 EVFILT_READ, EV_DISABLE, 0, 0, s);
263 EV_SET(&changes[nchanges++], s->server_fd,
264 EVFILT_WRITE, EV_ADD, 0, 0, s);
265 buffer_data(s, &s->server, linebuf + bwritten,
272 logmsg(LOG_ERR, "#%d client command too long or not"
277 } while (bread == buf_avail);
281 client_write(struct session *s)
285 written = write(s->client_fd, s->client.buffer + s->client.buffer_offset,
286 s->client.buffer_size - s->client.buffer_offset);
288 logmsg(LOG_ERR, "#%d write failed", s->id);
290 } else if (written == (s->client.buffer_size - s->client.buffer_offset)) {
291 free(s->client.buffer);
292 s->client.buffer = NULL;
293 s->client.buffer_size = 0;
294 s->client.buffer_offset = 0;
295 EV_SET(&changes[nchanges++], s->server_fd,
296 EVFILT_READ, EV_ENABLE, 0, 0, s);
298 s->client.buffer_offset += written;
307 pw = getpwnam(NOPRIV_USER);
312 if (chroot(CHROOT_DIR) != 0 || chdir("/") != 0 ||
313 setgroups(1, &pw->pw_gid) != 0 ||
314 setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0 ||
315 setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0)
322 end_session(struct session *s)
326 logmsg(LOG_INFO, "#%d ending session", s->id);
328 if (s->client_fd != -1)
330 if (s->server_fd != -1)
333 if (s->client.buffer)
334 free(s->client.buffer);
335 if (s->server.buffer)
336 free(s->server.buffer);
338 /* Remove rulesets by commiting empty ones. */
340 if (prepare_commit(s->id) == -1)
342 else if (do_commit() == -1) {
347 logmsg(LOG_ERR, "#%d pf rule removal failed: %s", s->id,
350 LIST_REMOVE(s, entry);
358 struct session *s, *tmp;
360 LIST_FOREACH_MUTABLE(s, &sessions, entry, tmp) {
374 getline(char *buf, size_t *valid)
378 if (*valid > MAX_LINE)
381 /* Copy to linebuf while searching for a newline. */
382 for (i = 0; i < *valid; i++) {
391 /* No newline found. */
400 linebuf[linelen] = '\0';
403 /* Move leftovers to the start. */
405 bcopy(buf + linelen, buf, *valid);
407 return ((int)linelen);
411 handle_connection(const int listen_fd)
413 struct sockaddr_storage tmp_ss;
414 struct sockaddr *client_sa, *server_sa, *fixed_server_sa;
415 struct sockaddr *client_to_proxy_sa, *proxy_to_server_sa;
418 int client_fd, fc, on;
421 * We _must_ accept the connection, otherwise libevent will keep
422 * coming back, and we will chew up all CPU.
424 client_sa = sstosa(&tmp_ss);
425 len = sizeof(struct sockaddr_storage);
426 if ((client_fd = accept(listen_fd, client_sa, &len)) < 0) {
427 logmsg(LOG_CRIT, "accept failed: %s", strerror(errno));
431 /* Refuse connection if the maximum is reached. */
432 if (session_count >= max_sessions) {
433 logmsg(LOG_ERR, "client limit (%d) reached, refusing "
434 "connection from %s", max_sessions, sock_ntop(client_sa));
439 /* Allocate session and copy back the info from the accept(). */
442 logmsg(LOG_CRIT, "init_session failed");
446 s->client_fd = client_fd;
447 memcpy(sstosa(&s->client_ss), client_sa, client_sa->sa_len);
449 /* Cast it once, and be done with it. */
450 client_sa = sstosa(&s->client_ss);
451 server_sa = sstosa(&s->server_ss);
452 client_to_proxy_sa = sstosa(&tmp_ss);
453 proxy_to_server_sa = sstosa(&s->proxy_ss);
454 fixed_server_sa = sstosa(&fixed_server_ss);
456 /* Log id/client early to ease debugging. */
457 logmsg(LOG_DEBUG, "#%d accepted connection from %s", s->id,
458 sock_ntop(client_sa));
461 * Find out the real server and port that the client wanted.
463 len = sizeof(struct sockaddr_storage);
464 if ((getsockname(s->client_fd, client_to_proxy_sa, &len)) < 0) {
465 logmsg(LOG_CRIT, "#%d getsockname failed: %s", s->id,
469 if (server_lookup(client_sa, client_to_proxy_sa, server_sa) != 0) {
470 logmsg(LOG_CRIT, "#%d server lookup failed (no rdr?)", s->id);
474 memcpy(sstosa(&s->orig_server_ss), server_sa,
476 memcpy(server_sa, fixed_server_sa, fixed_server_sa->sa_len);
479 /* XXX: check we are not connecting to ourself. */
482 * Setup socket and connect to server.
484 if ((s->server_fd = socket(server_sa->sa_family, SOCK_STREAM,
486 logmsg(LOG_CRIT, "#%d server socket failed: %s", s->id,
490 if (fixed_proxy && bind(s->server_fd, sstosa(&fixed_proxy_ss),
491 fixed_proxy_ss.ss_len) != 0) {
492 logmsg(LOG_CRIT, "#%d cannot bind fixed proxy address: %s",
493 s->id, strerror(errno));
497 /* Use non-blocking connect(), see CONNECT_TIMEOUT below. */
498 if ((fc = fcntl(s->server_fd, F_GETFL)) == -1 ||
499 fcntl(s->server_fd, F_SETFL, fc | O_NONBLOCK) == -1) {
500 logmsg(LOG_CRIT, "#%d cannot mark socket non-blocking: %s",
501 s->id, strerror(errno));
504 if (connect(s->server_fd, server_sa, server_sa->sa_len) < 0 &&
505 errno != EINPROGRESS) {
506 logmsg(LOG_CRIT, "#%d proxy cannot connect to server %s: %s",
507 s->id, sock_ntop(server_sa), strerror(errno));
511 len = sizeof(struct sockaddr_storage);
512 if ((getsockname(s->server_fd, proxy_to_server_sa, &len)) < 0) {
513 logmsg(LOG_CRIT, "#%d getsockname failed: %s", s->id,
518 logmsg(LOG_INFO, "#%d FTP session %d/%d started: client %s to server "
519 "%s via proxy %s ", s->id, session_count, max_sessions,
520 sock_ntop(client_sa), sock_ntop(server_sa),
521 sock_ntop(proxy_to_server_sa));
523 /* Keepalive is nice, but don't care if it fails. */
525 setsockopt(s->client_fd, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
527 setsockopt(s->server_fd, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
530 EV_SET(&changes[nchanges++], s->client_fd, EVFILT_READ, EV_ADD, 0, 0, s);
531 EV_SET(&changes[nchanges++], s->server_fd, EVFILT_READ, EV_ADD, 0, 0, s);
540 handle_signal(int sig)
543 * Signal handler rules don't apply.
546 logmsg(LOG_ERR, "%s exiting on signal %d", __progname, sig);
557 s = calloc(1, sizeof(struct session));
568 s->client.buffer = NULL;
569 s->client.buffer_size = 0;
570 s->client.buffer_offset = 0;
571 s->server.buffer = NULL;
572 s->server.buffer_size = 0;
573 s->server.buffer_offset = 0;
577 LIST_INSERT_HEAD(&sessions, s, entry);
584 logmsg(int pri, const char *message, ...)
591 va_start(ap, message);
594 /* syslog does its own vissing. */
595 vsyslog(pri, message, ap);
597 char buf[MAX_LOGLINE];
598 char visbuf[2 * MAX_LOGLINE];
600 /* We don't care about truncation. */
601 vsnprintf(buf, sizeof buf, message, ap);
602 strnvis(visbuf, buf, sizeof visbuf, VIS_CSTYLE | VIS_NL);
603 fprintf(stderr, "%s\n", visbuf);
610 main(int argc, char *argv[])
613 struct addrinfo hints, *res;
614 int kq, ch, error, listenfd, on;
622 fixed_server_port = "21";
625 listen_port = "8021";
626 loglevel = LOG_NOTICE;
633 /* Other initialization. */
638 while ((ch = getopt(argc, argv, "6Aa:b:D:dm:P:p:q:R:rt:v")) != -1) {
647 fixed_proxy = optarg;
653 loglevel = strtonum(optarg, LOG_EMERG, LOG_DEBUG,
656 errx(1, "loglevel %s", errstr);
662 max_sessions = strtonum(optarg, 1, 500, &errstr);
664 errx(1, "max sessions %s", errstr);
667 fixed_server_port = optarg;
670 listen_port = optarg;
673 if (strlen(optarg) >= PF_QNAME_SIZE)
674 errx(1, "queuename too long");
678 fixed_server = optarg;
684 timeout = strtonum(optarg, 0, 86400, &errstr);
686 errx(1, "timeout %s", errstr);
698 if (listen_ip == NULL)
699 listen_ip = ipv6_mode ? "::1" : "127.0.0.1";
701 /* Check for root to save the user from cryptic failure messages. */
703 errx(1, "needs to start as root");
705 /* Raise max. open files limit to satisfy max. sessions. */
706 rlp.rlim_cur = rlp.rlim_max = (2 * max_sessions) + 10;
707 if (setrlimit(RLIMIT_NOFILE, &rlp) == -1)
711 memset(&hints, 0, sizeof hints);
712 hints.ai_flags = AI_NUMERICHOST;
713 hints.ai_family = ipv6_mode ? AF_INET6 : AF_INET;
714 hints.ai_socktype = SOCK_STREAM;
715 error = getaddrinfo(fixed_proxy, NULL, &hints, &res);
717 errx(1, "getaddrinfo fixed proxy address failed: %s",
718 gai_strerror(error));
719 memcpy(&fixed_proxy_ss, res->ai_addr, res->ai_addrlen);
720 logmsg(LOG_INFO, "using %s to connect to servers",
721 sock_ntop(sstosa(&fixed_proxy_ss)));
726 memset(&hints, 0, sizeof hints);
727 hints.ai_family = ipv6_mode ? AF_INET6 : AF_INET;
728 hints.ai_socktype = SOCK_STREAM;
729 error = getaddrinfo(fixed_server, fixed_server_port, &hints,
732 errx(1, "getaddrinfo fixed server address failed: %s",
733 gai_strerror(error));
734 memcpy(&fixed_server_ss, res->ai_addr, res->ai_addrlen);
735 logmsg(LOG_INFO, "using fixed server %s",
736 sock_ntop(sstosa(&fixed_server_ss)));
740 /* Setup listener. */
741 memset(&hints, 0, sizeof hints);
742 hints.ai_flags = AI_NUMERICHOST | AI_PASSIVE;
743 hints.ai_family = ipv6_mode ? AF_INET6 : AF_INET;
744 hints.ai_socktype = SOCK_STREAM;
745 error = getaddrinfo(listen_ip, listen_port, &hints, &res);
747 errx(1, "getaddrinfo listen address failed: %s",
748 gai_strerror(error));
749 if ((listenfd = socket(res->ai_family, SOCK_STREAM, IPPROTO_TCP)) == -1)
750 errx(1, "socket failed");
752 if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, (void *)&on,
754 err(1, "setsockopt failed");
755 if (bind(listenfd, (struct sockaddr *)res->ai_addr,
756 (socklen_t)res->ai_addrlen) != 0)
757 err(1, "bind failed");
758 if (listen(listenfd, TCP_BACKLOG) != 0)
759 err(1, "listen failed");
763 init_filter(qname, verbose);
766 if (daemon(0, 0) == -1)
767 err(1, "cannot daemonize");
768 openlog(__progname, LOG_PID | LOG_NDELAY, LOG_DAEMON);
771 /* Use logmsg for output from here on. */
774 logmsg(LOG_ERR, "cannot drop privileges: %s", strerror(errno));
778 if ((kq = kqueue()) == -1) {
779 logmsg(LOG_ERR, "cannot create new kqueue(2): %s", strerror(errno));
783 /* Setup signal handler. */
784 signal(SIGPIPE, SIG_IGN);
785 EV_SET(&changes[nchanges++], SIGHUP, EVFILT_SIGNAL, EV_ADD, 0, 0, NULL);
786 EV_SET(&changes[nchanges++], SIGINT, EVFILT_SIGNAL, EV_ADD, 0, 0, NULL);
787 EV_SET(&changes[nchanges++], SIGTERM, EVFILT_SIGNAL, EV_ADD, 0, 0, NULL);
789 EV_SET(&changes[nchanges++], listenfd, EVFILT_READ, EV_ADD, 0, 0, NULL);
791 logmsg(LOG_NOTICE, "listening on %s port %s", listen_ip, listen_port);
796 struct kevent events[KQ_NEVENTS], *event;
799 nevents = kevent(kq, &changes[0], nchanges, &events[0],
802 logmsg(LOG_ERR, "cannot create new kqueue(2): %s", strerror(errno));
807 for (i = 0; i < nevents; ++i) {
810 if (event->filter == EVFILT_SIGNAL) {
811 handle_signal(event->ident);
815 if (event->ident == listenfd) {
816 /* Handle new connection */
817 handle_connection(event->ident);
819 /* Process existing connection */
820 s = (struct session *)event->udata;
822 if (event->ident == s->client_fd) {
823 if (event->filter == EVFILT_READ)
828 if (event->filter == EVFILT_READ)
835 /* The next loop might overflow changes */
836 if (nchanges > KQ_NEVENTS - 4)
850 unsigned int port, v[6];
854 /* Find the last space or left-parenthesis. */
855 for (p = linebuf + linelen; p > linebuf; p--)
856 if (*p == ' ' || *p == '(')
863 n = sscanf(p, " %u,%u,%u,%u,%u,%u", &v[0], &v[1], &v[2],
864 &v[3], &v[4], &v[5]);
865 if (n == 6 && v[0] < 256 && v[1] < 256 && v[2] < 256 &&
866 v[3] < 256 && v[4] < 256 && v[5] < 256)
867 return ((v[4] << 8) | v[5]);
870 n = sscanf(p, "(%u,%u,%u,%u,%u,%u)", &v[0], &v[1], &v[2],
871 &v[3], &v[4], &v[5]);
872 if (n == 6 && v[0] < 256 && v[1] < 256 && v[2] < 256 &&
873 v[3] < 256 && v[4] < 256 && v[5] < 256)
874 return ((v[4] << 8) | v[5]);
877 n = sscanf(p, "(|||%u|)", &port);
878 if (n == 1 && port < 65536)
882 n = sscanf(p, " |1|%u.%u.%u.%u|%u|", &v[0], &v[1], &v[2],
884 if (n == 5 && v[0] < 256 && v[1] < 256 && v[2] < 256 &&
885 v[3] < 256 && port < 65536)
887 n = sscanf(p, " |2|%*[a-fA-F0-9:]|%u|", &port);
888 if (n == 1 && port < 65536)
899 pick_proxy_port(void)
901 /* Random should be good enough for avoiding port collisions. */
902 return (IPPORT_HIFIRSTAUTO + (arc4random() %
903 (IPPORT_HILASTAUTO - IPPORT_HIFIRSTAUTO)));
907 proxy_reply(int cmd, struct sockaddr *sa, u_int16_t port)
913 r = snprintf(linebuf, sizeof linebuf,
914 "PORT %s,%u,%u\r\n", sock_ntop(sa), port / 256,
918 r = snprintf(linebuf, sizeof linebuf,
919 "227 Entering Passive Mode (%s,%u,%u)\r\n", sock_ntop(sa),
920 port / 256, port % 256);
923 if (sa->sa_family == AF_INET)
924 r = snprintf(linebuf, sizeof linebuf,
925 "EPRT |1|%s|%u|\r\n", sock_ntop(sa), port);
926 else if (sa->sa_family == AF_INET6)
927 r = snprintf(linebuf, sizeof linebuf,
928 "EPRT |2|%s|%u|\r\n", sock_ntop(sa), port);
931 r = snprintf(linebuf, sizeof linebuf,
932 "229 Entering Extended Passive Mode (|||%u|)\r\n", port);
936 if (r < 0 || r >= sizeof linebuf) {
937 logmsg(LOG_ERR, "proxy_reply failed: %d", r);
944 if (cmd == CMD_PORT || cmd == CMD_PASV) {
945 /* Replace dots in IP address with commas. */
946 for (i = 0; i < linelen; i++)
947 if (linebuf[i] == '.')
953 server_parse(struct session *s)
955 struct sockaddr *client_sa, *orig_sa, *proxy_sa, *server_sa;
958 if (s->cmd == CMD_NONE || linelen < 4 || linebuf[0] != '2')
962 * The pf rules below do quite some NAT rewriting, to keep up
963 * appearances. Points to keep in mind:
964 * 1) The client must think it's talking to the real server,
965 * for both control and data connections. Transparently.
966 * 2) The server must think that the proxy is the client.
967 * 3) Source and destination ports are rewritten to minimize
968 * port collisions, to aid security (some systems pick weak
969 * ports) or to satisfy RFC requirements (source port 20).
972 /* Cast this once, to make code below it more readable. */
973 client_sa = sstosa(&s->client_ss);
974 server_sa = sstosa(&s->server_ss);
975 proxy_sa = sstosa(&s->proxy_ss);
977 /* Fixed server: data connections must appear to come
978 from / go to the original server, not the fixed one. */
979 orig_sa = sstosa(&s->orig_server_ss);
981 /* Server not fixed: orig_server == server. */
982 orig_sa = sstosa(&s->server_ss);
985 if ((s->cmd == CMD_PASV && strncmp("227 ", linebuf, 4) == 0) ||
986 (s->cmd == CMD_EPSV && strncmp("229 ", linebuf, 4) == 0)) {
987 s->port = parse_port(s->cmd);
988 if (s->port < MIN_PORT) {
989 logmsg(LOG_CRIT, "#%d bad port in '%s'", s->id,
993 s->proxy_port = pick_proxy_port();
994 logmsg(LOG_INFO, "#%d passive: client to server port %d"
995 " via port %d", s->id, s->port, s->proxy_port);
997 if (prepare_commit(s->id) == -1)
1001 proxy_reply(s->cmd, orig_sa, s->proxy_port);
1002 logmsg(LOG_DEBUG, "#%d proxy: %s", s->id, linebuf);
1004 /* rdr from $client to $orig_server port $proxy_port -> $server
1006 if (add_rdr(s->id, client_sa, orig_sa, s->proxy_port,
1007 server_sa, s->port) == -1)
1010 /* nat from $client to $server port $port -> $proxy */
1011 if (add_nat(s->id, client_sa, server_sa, s->port, proxy_sa,
1012 PF_NAT_PROXY_PORT_LOW, PF_NAT_PROXY_PORT_HIGH) == -1)
1015 /* pass in from $client to $server port $port */
1016 if (add_filter(s->id, PF_IN, client_sa, server_sa,
1020 /* pass out from $proxy to $server port $port */
1021 if (add_filter(s->id, PF_OUT, proxy_sa, server_sa,
1027 if ((s->cmd == CMD_PORT || s->cmd == CMD_EPRT) &&
1028 strncmp("200 ", linebuf, 4) == 0) {
1029 logmsg(LOG_INFO, "#%d active: server to client port %d"
1030 " via port %d", s->id, s->port, s->proxy_port);
1032 if (prepare_commit(s->id) == -1)
1036 /* rdr from $server to $proxy port $proxy_port -> $client port
1038 if (add_rdr(s->id, server_sa, proxy_sa, s->proxy_port,
1039 client_sa, s->port) == -1)
1042 /* nat from $server to $client port $port -> $orig_server port
1044 if (rfc_mode && s->cmd == CMD_PORT) {
1045 /* Rewrite sourceport to RFC mandated 20. */
1046 if (add_nat(s->id, server_sa, client_sa, s->port,
1047 orig_sa, 20, 20) == -1)
1050 /* Let pf pick a source port from the standard range. */
1051 if (add_nat(s->id, server_sa, client_sa, s->port,
1052 orig_sa, PF_NAT_PROXY_PORT_LOW,
1053 PF_NAT_PROXY_PORT_HIGH) == -1)
1057 /* pass in from $server to $client port $port */
1058 if (add_filter(s->id, PF_IN, server_sa, client_sa, s->port) ==
1062 /* pass out from $orig_server to $client port $port */
1063 if (add_filter(s->id, PF_OUT, orig_sa, client_sa, s->port) ==
1068 /* Commit rules if they were prepared. */
1069 if (prepared && (do_commit() == -1)) {
1072 /* One more try if busy. */
1074 if (do_commit() == -1)
1085 logmsg(LOG_CRIT, "#%d pf operation failed: %s", s->id, strerror(errno));
1092 server_read(struct session *s)
1094 size_t buf_avail, bread, bwritten;
1098 buf_avail = sizeof s->sbuf - s->sbuf_valid;
1099 bread = read(s->server_fd, s->sbuf + s->sbuf_valid, buf_avail);
1100 s->sbuf_valid += bread;
1102 while ((n = getline(s->sbuf, &s->sbuf_valid)) > 0) {
1103 logmsg(LOG_DEBUG, "#%d server: %s", s->id, linebuf);
1104 if (!server_parse(s)) {
1108 bwritten = write(s->client_fd, linebuf, linelen);
1109 if (bwritten == -1) {
1110 logmsg(LOG_ERR, "#%d write failed", s->id);
1113 } else if (bwritten < linelen) {
1114 EV_SET(&changes[nchanges++], s->server_fd,
1115 EVFILT_READ, EV_DISABLE, 0, 0, s);
1116 EV_SET(&changes[nchanges++], s->client_fd,
1117 EVFILT_WRITE, EV_ADD, 0, 0, s);
1118 buffer_data(s, &s->client, linebuf + bwritten,
1119 linelen - bwritten);
1125 logmsg(LOG_ERR, "#%d server reply too long or not"
1130 } while (bread == buf_avail);
1134 server_write(struct session *s)
1138 written = write(s->server_fd, s->server.buffer + s->server.buffer_offset,
1139 s->server.buffer_size - s->server.buffer_offset);
1140 if (written == -1) {
1141 logmsg(LOG_ERR, "#%d write failed", s->id);
1143 } else if (written == (s->server.buffer_size - s->server.buffer_offset)) {
1144 free(s->server.buffer);
1145 s->server.buffer = NULL;
1146 s->server.buffer_size = 0;
1147 s->server.buffer_offset = 0;
1148 EV_SET(&changes[nchanges++], s->client_fd,
1149 EVFILT_READ, EV_ENABLE, 0, 0, s);
1151 s->server.buffer_offset += written;
1156 sock_ntop(struct sockaddr *sa)
1160 /* Cycle to next buffer. */
1161 n = (n + 1) % NTOP_BUFS;
1162 ntop_buf[n][0] = '\0';
1164 if (sa->sa_family == AF_INET) {
1165 struct sockaddr_in *sin = (struct sockaddr_in *)sa;
1167 return (inet_ntop(AF_INET, &sin->sin_addr, ntop_buf[n],
1168 sizeof ntop_buf[0]));
1171 if (sa->sa_family == AF_INET6) {
1172 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa;
1174 return (inet_ntop(AF_INET6, &sin6->sin6_addr, ntop_buf[n],
1175 sizeof ntop_buf[0]));
1184 fprintf(stderr, "usage: %s [-6Adrv] [-a address] [-b address]"
1185 " [-D level] [-m maxsessions]\n [-P port]"
1186 " [-p port] [-q queue] [-R address] [-t timeout]\n", __progname);