--- /dev/null
+/*
+# /usr/bin/tcpsvd -v 0 1234 true
+tcpsvd: info: pid 24916 from 127.0.0.1
+tcpsvd: info: start 24916 localhost:127.0.0.1 ::127.0.0.1:47905
+tcpsvd: info: pid 24918 from 127.0.0.1
+tcpsvd: info: start 24918 localhost:127.0.0.1 ::127.0.0.1:47906
+# ./busybox tcpsvd -v 0 1234 true
+tcpsvd: info: pid 24924 from 127.0.0.1
+tcpsvd: info: start 24924 localhost:1234:127.0.0.1:1234 ::127.0.0.1:47908
+tcpsvd: info: pid 24926 from 127.0.0.1
+tcpsvd: info: start 24926 localhost:1234:127.0.0.1:1234 ::127.0.0.1:47909
+*/
+
+#include "busybox.h"
+#include "ipsvd_perhost.h"
+
+#ifdef SSLSVD
+#include "matrixSsl.h"
+#include "ssl_io.h"
+#endif
+
+
+static unsigned max_per_host; /* originally in ipsvd_check.c */
+static unsigned cur_per_host;
+static unsigned verbose;
+static unsigned cnum;
+static unsigned cmax = 30;
+
+/* Must match getopt32 in main! */
+enum {
+ OPT_c = (1 << 0),
+ OPT_C = (1 << 1),
+ OPT_i = (1 << 2),
+ OPT_x = (1 << 3),
+ OPT_u = (1 << 4),
+ OPT_l = (1 << 5),
+ OPT_E = (1 << 6),
+ OPT_b = (1 << 7),
+ OPT_h = (1 << 8),
+ OPT_p = (1 << 9),
+ OPT_t = (1 << 10),
+ OPT_v = (1 << 11),
+ OPT_V = (1 << 12),
+ OPT_U = (1 << 13),
+ OPT_slash = (1 << 14),
+ OPT_Z = (1 << 15),
+ OPT_K = (1 << 16),
+};
+
+static void connection_status(void)
+{
+ printf("%s: info: status %u/%u\n", applet_name, cnum, cmax);
+}
+
+static void sig_term_handler(int sig)
+{
+ if (verbose)
+ printf("%s: info: sigterm received, exit\n", applet_name);
+ exit(0);
+}
+
+static void sig_child_handler(int sig)
+{
+ int wstat;
+ int pid;
+
+ while ((pid = wait_nohang(&wstat)) > 0) {
+ if (max_per_host)
+ ipsvd_perhost_remove(pid);
+ if (cnum)
+ cnum--;
+ if (verbose) {
+ /* Little bloated, but tries to give accurate info
+ * how child exited. Makes easier to spot segfaulting
+ * children etc... */
+ unsigned e = 0;
+ const char *cause = "?exit";
+ if (WIFEXITED(wstat)) {
+ cause++;
+ e = WEXITSTATUS(wstat);
+ } else if (WIFSIGNALED(wstat)) {
+ cause = "signal";
+ e = WTERMSIG(wstat);
+ }
+ printf("%s: info: end %d %s %d\n",
+ applet_name, pid, cause, e);
+ }
+ }
+ if (verbose)
+ connection_status();
+}
+
+int tcpsvd_main(int argc, char **argv);
+int tcpsvd_main(int argc, char **argv)
+{
+ char *str_c, *str_C, *str_b, *str_t;
+ char *user;
+ struct hcc *hccp;
+ const char *instructs;
+ char *msg_per_host = NULL;
+ unsigned len_per_host = len_per_host; /* gcc */
+ int need_addresses;
+ int pid;
+ int sock;
+ int conn;
+ unsigned backlog = 20;
+ union {
+ struct sockaddr sa;
+ struct sockaddr_in sin;
+ USE_FEATURE_IPV6(struct sockaddr_in6 sin6;)
+ } sock_adr;
+ socklen_t sockadr_size;
+ uint16_t local_port = local_port;
+ uint16_t remote_port;
+ unsigned port;
+ char *local_hostname = NULL;
+ char *remote_hostname = (char*)""; /* "" used if no -h */
+ char *local_ip = local_ip;
+ char *remote_ip = NULL;
+ //unsigned iscdb = 0; /* = option_mask32 & OPT_x (TODO) */
+ //unsigned long timeout = 0;
+#ifndef SSLSVD
+ struct bb_uidgid_t ugid;
+#endif
+
+ /* 3+ args, -i at most once, -p implies -h, -v is counter */
+ opt_complementary = "-3:?:i--i:ph:vv";
+#ifdef SSLSVD
+ getopt32(argc, argv, "c:C:i:x:u:l:Eb:hpt:vU:/:Z:K:",
+ &str_c, &str_C, &instructs, &instructs, &user, &local_hostname,
+ &str_b, &str_t, &ssluser, &root, &cert, &key, &verbose
+ );
+#else
+ getopt32(argc, argv, "c:C:i:x:u:l:Eb:hpt:v",
+ &str_c, &str_C, &instructs, &instructs, &user, &local_hostname,
+ &str_b, &str_t, &verbose
+ );
+#endif
+ if (option_mask32 & OPT_c)
+ cmax = xatou_range(str_c, 1, INT_MAX);
+ if (option_mask32 & OPT_C) { /* -C n[:message] */
+ max_per_host = bb_strtou(str_C, &str_C, 10);
+ if (str_C[0]) {
+ if (str_C[0] != ':')
+ bb_show_usage();
+ msg_per_host = str_C + 1;
+ len_per_host = strlen(msg_per_host);
+ }
+ }
+ if (max_per_host > cmax)
+ max_per_host = cmax;
+ if (option_mask32 & OPT_u) {
+ if (!get_uidgid(&ugid, user, 1))
+ bb_error_msg_and_die("unknown user/group: %s", user);
+ }
+ if (option_mask32 & OPT_b)
+ backlog = xatou(str_b);
+// if (option_mask32 & OPT_t) timeout = xatou(str_t);
+#ifdef SSLSVD
+ if (option_mask32 & OPT_U) ssluser = (char*)optarg; break;
+ if (option_mask32 & OPT_slash) root = (char*)optarg; break;
+ if (option_mask32 & OPT_Z) cert = (char*)optarg; break;
+ if (option_mask32 & OPT_K) key = (char*)optarg; break;
+#endif
+ argv += optind;
+ if (!argv[0][0] || LONE_CHAR(argv[0], '0'))
+ argv[0] = (char*)"0.0.0.0";
+
+ need_addresses = verbose || !(option_mask32 & OPT_E);
+
+#ifdef SSLSVD
+ sslser = user;
+ client = 0;
+ if ((getuid() == 0) && !(option_mask32 & OPT_u)) {
+ xfunc_exitcode = 100;
+ bb_error_msg_and_die("fatal: -U ssluser must be set when running as root");
+ }
+ if (option_mask32 & OPT_u)
+ if (!uidgid_get(&sslugid, ssluser, 1)) {
+ if (errno) {
+ xfunc_exitcode = 100;
+ bb_perror_msg_and_die("fatal: cannot get user/group: %s", ssluser);
+ }
+ xfunc_exitcode = 111;
+ bb_error_msg_and_die("fatal: unknown user/group '%s'", ssluser);
+ }
+ if (!cert) cert = "./cert.pem";
+ if (!key) key = cert;
+ if (matrixSslOpen() < 0)
+ fatal("cannot initialize ssl");
+ if (matrixSslReadKeys(&keys, cert, key, 0, ca) < 0) {
+ if (client)
+ fatal("cannot read cert, key, or ca file");
+ fatal("cannot read cert or key file");
+ }
+ if (matrixSslNewSession(&ssl, keys, 0, SSL_FLAGS_SERVER) < 0)
+ fatal("cannot create ssl session");
+#endif
+
+ sig_block(SIGCHLD);
+ signal(SIGCHLD, sig_child_handler);
+ signal(SIGTERM, sig_term_handler);
+ signal(SIGPIPE, SIG_IGN);
+
+ if (max_per_host)
+ ipsvd_perhost_init(cmax);
+
+ port = bb_lookup_port(argv[1], "tcp", 0);
+ sock = create_and_bind_stream_or_die(argv[0], port);
+ xlisten(sock, backlog);
+ /* ndelay_off(sock); - it is the default I think? */
+
+#ifndef SSLSVD
+ if (option_mask32 & OPT_u) {
+ /* drop permissions */
+ xsetgid(ugid.gid);
+ xsetuid(ugid.uid);
+ }
+#endif
+ bb_sanitize_stdio(); /* fd# 1,2 must be opened */
+ close(0);
+
+ if (verbose) {
+ /* we do it only for ":port" cosmetics... oh well */
+ len_and_sockaddr *lsa = xhost2sockaddr(argv[0], port);
+ char *addr = xmalloc_sockaddr2dotted(&lsa->sa, lsa->len);
+
+ printf("%s: info: listening on %s", applet_name, addr);
+ free(addr);
+#ifndef SSLSVD
+ if (option_mask32 & OPT_u)
+ printf(", uid %u, gid %u",
+ (unsigned)ugid.uid, (unsigned)ugid.uid);
+#endif
+ puts(", starting");
+ }
+
+ /* The rest is a main accept() loop */
+
+ again:
+ hccp = NULL;
+
+ while (cnum >= cmax)
+ sig_pause(); /* wait for any signal (expecting SIGCHLD) */
+
+ sockadr_size = sizeof(sock_adr);
+ sig_unblock(SIGCHLD);
+ conn = accept(sock, &sock_adr.sa, &sockadr_size);
+ sig_block(SIGCHLD);
+ if (conn == -1) {
+ if (errno != EINTR)
+ bb_perror_msg("accept");
+ goto again;
+ }
+
+ if (max_per_host) {
+ /* we drop connection immediately if cur_per_host > max_per_host
+ * (minimizing load under SYN flood) */
+ free(remote_ip);
+ remote_ip = xmalloc_sockaddr2dotted_noport(&sock_adr.sa, sockadr_size);
+ cur_per_host = ipsvd_perhost_add(remote_ip, max_per_host, &hccp);
+ if (cur_per_host > max_per_host) {
+ /* ipsvd_perhost_add detected that max is exceeded
+ * (and did not store us in connection table) */
+ if (msg_per_host) {
+ ndelay_on(conn);
+ /* don't test for errors */
+ write(conn, msg_per_host, len_per_host);
+ }
+ close(conn);
+ goto again;
+ }
+ }
+
+ cnum++;
+ if (verbose)
+ connection_status();
+
+ pid = fork();
+ if (pid == -1) {
+ bb_perror_msg("fork");
+ close(conn);
+ goto again;
+ }
+ if (pid != 0) {
+ /* parent */
+ close(conn);
+ if (hccp)
+ hccp->pid = pid;
+ goto again;
+ }
+
+ /* Child: prepare env, log, and exec prog */
+
+ close(sock);
+
+ if (!max_per_host)
+ remote_ip = xmalloc_sockaddr2dotted_noport(&sock_adr.sa, sizeof(sock_adr));
+ /* else it is already done */
+
+ remote_port = get_nport(&sock_adr.sa);
+ remote_port = ntohs(remote_port);
+
+ if (verbose) {
+ pid = getpid();
+ printf("%s: info: pid %d from %s\n", applet_name, pid, remote_ip);
+ }
+
+ if (need_addresses && (option_mask32 & OPT_h)) {
+ remote_hostname = xmalloc_sockaddr2host(&sock_adr.sa, sizeof(sock_adr));
+ if (!remote_hostname) {
+ bb_error_msg("warning: cannot look up hostname for %s", remote_ip);
+ remote_hostname = (char*)"";
+ }
+ }
+
+ sockadr_size = sizeof(sock_adr);
+ /* Errors ignored (I'm not paranoid enough to imagine kernel
+ * which doesn't know local ip) */
+ getsockname(conn, &sock_adr.sa, &sockadr_size);
+
+ if (need_addresses) {
+ local_ip = xmalloc_sockaddr2dotted_noport(&sock_adr.sa, sockadr_size);
+ local_port = get_nport(&sock_adr.sa);
+ local_port = ntohs(local_port);
+ if (!local_hostname) {
+ local_hostname = xmalloc_sockaddr2host_noport(&sock_adr.sa, sockadr_size);
+ if (!local_hostname)
+ bb_error_msg_and_die("cannot look up local hostname for %s", local_ip);
+ }
+ }
+
+ if (!(option_mask32 & OPT_E)) {
+ /* setup ucspi env */
+ xsetenv("PROTO", "TCP");
+ xsetenv("TCPLOCALIP", local_ip);
+ xsetenv("TCPLOCALPORT", utoa(local_port));
+ xsetenv("TCPLOCALHOST", local_hostname);
+ xsetenv("TCPREMOTEIP", remote_ip);
+ xsetenv("TCPREMOTEPORT", utoa(remote_port));
+ if (option_mask32 & OPT_h) {
+ xsetenv("TCPREMOTEHOST", remote_hostname);
+ }
+ xsetenv("TCPREMOTEINFO", "");
+ /* additional */
+ if (cur_per_host > 0)
+ xsetenv("TCPCONCURRENCY", utoa(cur_per_host));
+ }
+
+#if 0
+ if (instructs) {
+ ac = ipsvd_check(iscdb, &inst, &match, (char*)instructs,
+ remote_ip, remote_hostname, timeout);
+ if (ac == -1) drop2("cannot check inst", remote_ip);
+ if (ac == IPSVD_ERR) drop2("cannot read", (char*)instructs);
+ } else
+ ac = IPSVD_DEFAULT;
+#endif
+
+ if (max_per_host && verbose)
+ printf("%s: info: concurrency %u %s %u/%u\n",
+ applet_name, pid, remote_ip, cur_per_host, max_per_host);
+
+ if (verbose) {
+ printf("%s: info: start %u %s:%s :%s:%s:%u\n",
+ applet_name, pid,
+ local_hostname, local_ip,
+ remote_hostname, remote_ip, (unsigned)remote_port);
+#if 0
+ switch(ac) {
+ case IPSVD_DENY:
+ printf("deny "); break;
+ case IPSVD_DEFAULT:
+ case IPSVD_INSTRUCT:
+ printf("start "); break;
+ case IPSVD_EXEC:
+ printf("exec "); break;
+ }
+ ...
+ if (instructs) {
+ printf(" ");
+ if (iscdb) {
+ printf((char*)instructs);
+ printf("/");
+ }
+ outfix(match.s);
+ if(inst.s && inst.len && (verbose > 1)) {
+ printf(": ");
+ printf(&inst);
+ }
+ }
+ printf("\n");
+#endif
+ }
+
+#if 0
+ if (ac == IPSVD_DENY) {
+ close(conn);
+ _exit(100);
+ }
+ if (ac == IPSVD_EXEC) {
+ args[0] = "/bin/sh";
+ args[1] = "-c";
+ args[2] = inst.s;
+ args[3] = 0;
+ run = args;
+ } else
+ run = argv + 2; /* below: we use argv+2 (was using run) */
+#endif
+
+ xmove_fd(conn, 0);
+ dup2(0, 1);
+ signal(SIGTERM, SIG_DFL);
+ signal(SIGPIPE, SIG_DFL);
+ signal(SIGCHLD, SIG_DFL);
+ sig_unblock(SIGCHLD);
+
+ argv += 2;
+#ifdef SSLSVD
+ strcpy(id, utoa(pid);
+ ssl_io(0, argv);
+#else
+ BB_EXECVP(argv[0], argv);
+#endif
+ bb_perror_msg_and_die("exec '%s'", argv[0]);
+}
+
+/*
+tcpsvd [-hpEvv] [-c n] [-C n:msg] [-b n] [-u user] [-l name] [-i dir|-x cdb] [ -t sec] host port prog
+
+tcpsvd creates a TCP/IP socket, binds it to the address host:port,
+and listens on the socket for incoming connections.
+
+On each incoming connection, tcpsvd conditionally runs a program,
+with standard input reading from the socket, and standard output
+writing to the socket, to handle this connection. tcpsvd keeps
+listening on the socket for new connections, and can handle
+multiple connections simultaneously.
+
+tcpsvd optionally checks for special instructions depending
+on the IP address or hostname of the client that initiated
+the connection, see ipsvd-instruct(5).
+
+host
+ host either is a hostname, or a dotted-decimal IP address,
+ or 0. If host is 0, tcpsvd accepts connections to any local
+ IP address.
+port
+ tcpsvd accepts connections to host:port. port may be a name
+ from /etc/services or a number.
+prog
+ prog consists of one or more arguments. For each connection,
+ tcpsvd normally runs prog, with file descriptor 0 reading from
+ the network, and file descriptor 1 writing to the network.
+ By default it also sets up TCP-related environment variables,
+ see tcp-environ(5)
+-i dir
+ read instructions for handling new connections from the instructions
+ directory dir. See ipsvd-instruct(5) for details.
+-x cdb
+ read instructions for handling new connections from the constant database
+ cdb. The constant database normally is created from an instructions
+ directory by running ipsvd-cdb(8).
+-t sec
+ timeout. This option only takes effect if the -i option is given.
+ While checking the instructions directory, check the time of last access
+ of the file that matches the clients address or hostname if any, discard
+ and remove the file if it wasn't accessed within the last sec seconds;
+ tcpsvd does not discard or remove a file if the user's write permission
+ is not set, for those files the timeout is disabled. Default is 0,
+ which means that the timeout is disabled.
+-l name
+ local hostname. Do not look up the local hostname in DNS, but use name
+ as hostname. This option must be set if tcpsvd listens on port 53
+ to avoid loops.
+-u user[:group]
+ drop permissions. Switch user ID to user's UID, and group ID to user's
+ primary GID after creating and binding to the socket. If user is followed
+ by a colon and a group name, the group ID is switched to the GID of group
+ instead. All supplementary groups are removed.
+-c n
+ concurrency. Handle up to n connections simultaneously. Default is 30.
+ If there are n connections active, tcpsvd defers acceptance of a new
+ connection until an active connection is closed.
+-C n[:msg]
+ per host concurrency. Allow only up to n connections from the same IP
+ address simultaneously. If there are n active connections from one IP
+ address, new incoming connections from this IP address are closed
+ immediately. If n is followed by :msg, the message msg is written
+ to the client if possible, before closing the connection. By default
+ msg is empty. See ipsvd-instruct(5) for supported escape sequences in msg.
+
+ For each accepted connection, the current per host concurrency is
+ available through the environment variable TCPCONCURRENCY. n and msg
+ can be overwritten by ipsvd(7) instructions, see ipsvd-instruct(5).
+ By default tcpsvd doesn't keep track of connections.
+-h
+ Look up the client's hostname in DNS.
+-p
+ paranoid. After looking up the client's hostname in DNS, look up the IP
+ addresses in DNS for that hostname, and forget about the hostname
+ if none of the addresses match the client's IP address. You should
+ set this option if you use hostname based instructions. The -p option
+ implies the -h option.
+-b n
+ backlog. Allow a backlog of approximately n TCP SYNs. On some systems n
+ is silently limited. Default is 20.
+-E
+ no special environment. Do not set up TCP-related environment variables.
+-v
+ verbose. Print verbose messsages to standard output.
+-vv
+ more verbose. Print more verbose messages to standard output.
+*/
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