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Diffstat (limited to 'release/src/router/busybox/networking/tcpudp.c')
-rw-r--r--release/src/router/busybox/networking/tcpudp.c607
1 files changed, 607 insertions, 0 deletions
diff --git a/release/src/router/busybox/networking/tcpudp.c b/release/src/router/busybox/networking/tcpudp.c
new file mode 100644
index 00000000..55a3e089
--- /dev/null
+++ b/release/src/router/busybox/networking/tcpudp.c
@@ -0,0 +1,607 @@
+/* Based on ipsvd utilities written by Gerrit Pape <pape@smarden.org>
+ * which are released into public domain by the author.
+ * Homepage: http://smarden.sunsite.dk/ipsvd/
+ *
+ * Copyright (C) 2007 Denys Vlasenko.
+ *
+ * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ */
+
+/* Based on ipsvd-0.12.1. This tcpsvd accepts all options
+ * which are supported by one from ipsvd-0.12.1, but not all are
+ * functional. See help text at the end of this file for details.
+ *
+ * Code inside "#ifdef SSLSVD" is for sslsvd and is currently unused.
+ *
+ * Busybox version exports TCPLOCALADDR instead of
+ * TCPLOCALIP + TCPLOCALPORT pair. ADDR more closely matches reality
+ * (which is "struct sockaddr_XXX". Port is not a separate entity,
+ * it's just a part of (AF_INET[6]) sockaddr!).
+ *
+ * TCPORIGDSTADDR is Busybox-specific addition.
+ *
+ * udp server is hacked up by reusing TCP code. It has the following
+ * limitation inherent in Unix DGRAM sockets implementation:
+ * - local IP address is retrieved (using recvmsg voodoo) but
+ * child's socket is not bound to it (bind cannot be called on
+ * already bound socket). Thus it still can emit outgoing packets
+ * with wrong source IP...
+ * - don't know how to retrieve ORIGDST for udp.
+ */
+
+#include "libbb.h"
+/* Wants <limits.h> etc, thus included after libbb.h: */
+#include <linux/types.h> /* for __be32 etc */
+#include <linux/netfilter_ipv4.h>
+
+// TODO: move into this file:
+#include "tcpudp_perhost.h"
+
+#ifdef SSLSVD
+#include "matrixSsl.h"
+#include "ssl_io.h"
+#endif
+
+struct globals {
+ unsigned verbose;
+ unsigned max_per_host;
+ unsigned cur_per_host;
+ unsigned cnum;
+ unsigned cmax;
+ char **env_cur;
+ char *env_var[1]; /* actually bigger */
+};
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define verbose (G.verbose )
+#define max_per_host (G.max_per_host)
+#define cur_per_host (G.cur_per_host)
+#define cnum (G.cnum )
+#define cmax (G.cmax )
+#define env_cur (G.env_cur )
+#define env_var (G.env_var )
+#define INIT_G() do { \
+ cmax = 30; \
+ env_cur = &env_var[0]; \
+} while (0)
+
+
+/* We have to be careful about leaking memory in repeated setenv's */
+static void xsetenv_plain(const char *n, const char *v)
+{
+ char *var = xasprintf("%s=%s", n, v);
+ *env_cur++ = var;
+ putenv(var);
+}
+
+static void xsetenv_proto(const char *proto, const char *n, const char *v)
+{
+ char *var = xasprintf("%s%s=%s", proto, n, v);
+ *env_cur++ = var;
+ putenv(var);
+}
+
+static void undo_xsetenv(void)
+{
+ char **pp = env_cur = &env_var[0];
+ while (*pp) {
+ char *var = *pp;
+ bb_unsetenv(var);
+ free(var);
+ *pp++ = NULL;
+ }
+}
+
+static void sig_term_handler(int sig)
+{
+ if (verbose)
+ bb_error_msg("got signal %u, exit", sig);
+ kill_myself_with_sig(sig);
+}
+
+/* Little bloated, but tries to give accurate info how child exited.
+ * Makes easier to spot segfaulting children etc... */
+static void print_waitstat(unsigned pid, int wstat)
+{
+ unsigned e = 0;
+ const char *cause = "?exit";
+
+ if (WIFEXITED(wstat)) {
+ cause++;
+ e = WEXITSTATUS(wstat);
+ } else if (WIFSIGNALED(wstat)) {
+ cause = "signal";
+ e = WTERMSIG(wstat);
+ }
+ bb_error_msg("end %d %s %d", pid, cause, e);
+}
+
+/* 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), /* from here: sslsvd only */
+ OPT_slash = (1 << 14),
+ OPT_Z = (1 << 15),
+ OPT_K = (1 << 16),
+};
+
+static void connection_status(void)
+{
+ /* "only 1 client max" desn't need this */
+ if (cmax > 1)
+ bb_error_msg("status %u/%u", cnum, cmax);
+}
+
+static void sig_child_handler(int sig UNUSED_PARAM)
+{
+ int wstat;
+ pid_t pid;
+
+ while ((pid = wait_any_nohang(&wstat)) > 0) {
+ if (max_per_host)
+ ipsvd_perhost_remove(pid);
+ if (cnum)
+ cnum--;
+ if (verbose)
+ print_waitstat(pid, wstat);
+ }
+ if (verbose)
+ connection_status();
+}
+
+int tcpudpsvd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int tcpudpsvd_main(int argc UNUSED_PARAM, char **argv)
+{
+ char *str_C, *str_t;
+ char *user;
+ struct hcc *hccp;
+ const char *instructs;
+ char *msg_per_host = NULL;
+ unsigned len_per_host = len_per_host; /* gcc */
+#ifndef SSLSVD
+ struct bb_uidgid_t ugid;
+#endif
+ bool tcp;
+ uint16_t local_port;
+ char *preset_local_hostname = NULL;
+ char *remote_hostname = remote_hostname; /* for compiler */
+ char *remote_addr = remote_addr; /* for compiler */
+ len_and_sockaddr *lsa;
+ len_and_sockaddr local, remote;
+ socklen_t sa_len;
+ int pid;
+ int sock;
+ int conn;
+ unsigned backlog = 20;
+
+ INIT_G();
+
+ tcp = (applet_name[0] == 't');
+
+ /* 3+ args, -i at most once, -p implies -h, -v is counter, -b N, -c N */
+ opt_complementary = "-3:i--i:ph:vv:b+:c+";
+#ifdef SSLSVD
+ getopt32(argv, "+c:C:i:x:u:l:Eb:hpt:vU:/:Z:K:",
+ &cmax, &str_C, &instructs, &instructs, &user, &preset_local_hostname,
+ &backlog, &str_t, &ssluser, &root, &cert, &key, &verbose
+ );
+#else
+ /* "+": stop on first non-option */
+ getopt32(argv, "+c:C:i:x:u:l:Eb:hpt:v",
+ &cmax, &str_C, &instructs, &instructs, &user, &preset_local_hostname,
+ &backlog, &str_t, &verbose
+ );
+#endif
+ 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) {
+ xget_uidgid(&ugid, user);
+ }
+#ifdef SSLSVD
+ if (option_mask32 & OPT_U) ssluser = optarg;
+ if (option_mask32 & OPT_slash) root = optarg;
+ if (option_mask32 & OPT_Z) cert = optarg;
+ if (option_mask32 & OPT_K) key = optarg;
+#endif
+ argv += optind;
+ if (!argv[0][0] || LONE_CHAR(argv[0], '0'))
+ argv[0] = (char*)"0.0.0.0";
+
+ /* Per-IP flood protection is not thought-out for UDP */
+ if (!tcp)
+ max_per_host = 0;
+
+ bb_sanitize_stdio(); /* fd# 0,1,2 must be opened */
+
+#ifdef SSLSVD
+ sslser = user;
+ client = 0;
+ if ((getuid() == 0) && !(option_mask32 & OPT_u)) {
+ xfunc_exitcode = 100;
+ bb_error_msg_and_die("-U ssluser must be set when running as root");
+ }
+ if (option_mask32 & OPT_u)
+ if (!uidgid_get(&sslugid, ssluser, 1)) {
+ if (errno) {
+ bb_perror_msg_and_die("can't get user/group: %s", ssluser);
+ }
+ bb_error_msg_and_die("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);
+ bb_signals(BB_FATAL_SIGS, sig_term_handler);
+ signal(SIGPIPE, SIG_IGN);
+
+ if (max_per_host)
+ ipsvd_perhost_init(cmax);
+
+ local_port = bb_lookup_port(argv[1], tcp ? "tcp" : "udp", 0);
+ lsa = xhost2sockaddr(argv[0], local_port);
+ argv += 2;
+
+ sock = xsocket(lsa->u.sa.sa_family, tcp ? SOCK_STREAM : SOCK_DGRAM, 0);
+ setsockopt_reuseaddr(sock);
+ sa_len = lsa->len; /* I presume sockaddr len stays the same */
+ xbind(sock, &lsa->u.sa, sa_len);
+ if (tcp)
+ xlisten(sock, backlog);
+ else /* udp: needed for recv_from_to to work: */
+ socket_want_pktinfo(sock);
+ /* 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
+
+ if (verbose) {
+ char *addr = xmalloc_sockaddr2dotted(&lsa->u.sa);
+ bb_error_msg("listening on %s, starting", addr);
+ free(addr);
+#ifndef SSLSVD
+ if (option_mask32 & OPT_u)
+ printf(", uid %u, gid %u",
+ (unsigned)ugid.uid, (unsigned)ugid.gid);
+#endif
+ }
+
+ /* Main accept() loop */
+
+ again:
+ hccp = NULL;
+
+ while (cnum >= cmax)
+ wait_for_any_sig(); /* expecting SIGCHLD */
+
+ /* Accept a connection to fd #0 */
+ again1:
+ close(0);
+ again2:
+ sig_unblock(SIGCHLD);
+ local.len = remote.len = sa_len;
+ if (tcp) {
+ conn = accept(sock, &remote.u.sa, &remote.len);
+ } else {
+ /* In case recv_from_to won't be able to recover local addr.
+ * Also sets port - recv_from_to is unable to do it. */
+ local = *lsa;
+ conn = recv_from_to(sock, NULL, 0, MSG_PEEK,
+ &remote.u.sa, &local.u.sa, sa_len);
+ }
+ sig_block(SIGCHLD);
+ if (conn < 0) {
+ if (errno != EINTR)
+ bb_perror_msg(tcp ? "accept" : "recv");
+ goto again2;
+ }
+ xmove_fd(tcp ? conn : sock, 0);
+
+ if (max_per_host) {
+ /* Drop connection immediately if cur_per_host > max_per_host
+ * (minimizing load under SYN flood) */
+ remote_addr = xmalloc_sockaddr2dotted_noport(&remote.u.sa);
+ cur_per_host = ipsvd_perhost_add(remote_addr, max_per_host, &hccp);
+ if (cur_per_host > max_per_host) {
+ /* ipsvd_perhost_add detected that max is exceeded
+ * (and did not store ip in connection table) */
+ free(remote_addr);
+ if (msg_per_host) {
+ /* don't block or test for errors */
+ send(0, msg_per_host, len_per_host, MSG_DONTWAIT);
+ }
+ goto again1;
+ }
+ /* NB: remote_addr is not leaked, it is stored in conn table */
+ }
+
+ if (!tcp) {
+ /* Voodoo magic: making udp sockets each receive its own
+ * packets is not trivial, and I still not sure
+ * I do it 100% right.
+ * 1) we have to do it before fork()
+ * 2) order is important - is it right now? */
+
+ /* Open new non-connected UDP socket for further clients... */
+ sock = xsocket(lsa->u.sa.sa_family, SOCK_DGRAM, 0);
+ setsockopt_reuseaddr(sock);
+ /* Make plain write/send work for old socket by supplying default
+ * destination address. This also restricts incoming packets
+ * to ones coming from this remote IP. */
+ xconnect(0, &remote.u.sa, sa_len);
+ /* hole? at this point we have no wildcard udp socket...
+ * can this cause clients to get "port unreachable" icmp?
+ * Yup, time window is very small, but it exists (is it?) */
+ /* ..."open new socket", continued */
+ xbind(sock, &lsa->u.sa, sa_len);
+ socket_want_pktinfo(sock);
+
+ /* Doesn't work:
+ * we cannot replace fd #0 - we will lose pending packet
+ * which is already buffered for us! And we cannot use fd #1
+ * instead - it will "intercept" all following packets, but child
+ * does not expect data coming *from fd #1*! */
+#if 0
+ /* Make it so that local addr is fixed to localp->u.sa
+ * and we don't accidentally accept packets to other local IPs. */
+ /* NB: we possibly bind to the _very_ same_ address & port as the one
+ * already bound in parent! This seems to work in Linux.
+ * (otherwise we can move socket to fd #0 only if bind succeeds) */
+ close(0);
+ set_nport(localp, htons(local_port));
+ xmove_fd(xsocket(localp->u.sa.sa_family, SOCK_DGRAM, 0), 0);
+ setsockopt_reuseaddr(0); /* crucial */
+ xbind(0, &localp->u.sa, localp->len);
+#endif
+ }
+
+ pid = vfork();
+ if (pid == -1) {
+ bb_perror_msg("vfork");
+ goto again;
+ }
+
+ if (pid != 0) {
+ /* Parent */
+ cnum++;
+ if (verbose)
+ connection_status();
+ if (hccp)
+ hccp->pid = pid;
+ /* clean up changes done by vforked child */
+ undo_xsetenv();
+ goto again;
+ }
+
+ /* Child: prepare env, log, and exec prog */
+
+ /* Closing tcp listening socket */
+ if (tcp)
+ close(sock);
+
+ { /* vfork alert! every xmalloc in this block should be freed! */
+ char *local_hostname = local_hostname; /* for compiler */
+ char *local_addr = NULL;
+ char *free_me0 = NULL;
+ char *free_me1 = NULL;
+ char *free_me2 = NULL;
+
+ if (verbose || !(option_mask32 & OPT_E)) {
+ if (!max_per_host) /* remote_addr is not yet known */
+ free_me0 = remote_addr = xmalloc_sockaddr2dotted(&remote.u.sa);
+ if (option_mask32 & OPT_h) {
+ free_me1 = remote_hostname = xmalloc_sockaddr2host_noport(&remote.u.sa);
+ if (!remote_hostname) {
+ bb_error_msg("cannot look up hostname for %s", remote_addr);
+ remote_hostname = remote_addr;
+ }
+ }
+ /* Find out local IP peer connected to.
+ * Errors ignored (I'm not paranoid enough to imagine kernel
+ * which doesn't know local IP). */
+ if (tcp)
+ getsockname(0, &local.u.sa, &local.len);
+ /* else: for UDP it is done earlier by parent */
+ local_addr = xmalloc_sockaddr2dotted(&local.u.sa);
+ if (option_mask32 & OPT_h) {
+ local_hostname = preset_local_hostname;
+ if (!local_hostname) {
+ free_me2 = local_hostname = xmalloc_sockaddr2host_noport(&local.u.sa);
+ if (!local_hostname)
+ bb_error_msg_and_die("cannot look up hostname for %s", local_addr);
+ }
+ /* else: local_hostname is not NULL, but is NOT malloced! */
+ }
+ }
+ if (verbose) {
+ pid = getpid();
+ if (max_per_host) {
+ bb_error_msg("concurrency %s %u/%u",
+ remote_addr,
+ cur_per_host, max_per_host);
+ }
+ bb_error_msg((option_mask32 & OPT_h)
+ ? "start %u %s-%s (%s-%s)"
+ : "start %u %s-%s",
+ pid,
+ local_addr, remote_addr,
+ local_hostname, remote_hostname);
+ }
+
+ if (!(option_mask32 & OPT_E)) {
+ /* setup ucspi env */
+ const char *proto = tcp ? "TCP" : "UDP";
+
+ /* Extract "original" destination addr:port
+ * from Linux firewall. Useful when you redirect
+ * an outbond connection to local handler, and it needs
+ * to know where it originally tried to connect */
+ if (tcp && getsockopt(0, SOL_IP, SO_ORIGINAL_DST, &local.u.sa, &local.len) == 0) {
+ char *addr = xmalloc_sockaddr2dotted(&local.u.sa);
+ xsetenv_plain("TCPORIGDSTADDR", addr);
+ free(addr);
+ }
+ xsetenv_plain("PROTO", proto);
+ xsetenv_proto(proto, "LOCALADDR", local_addr);
+ xsetenv_proto(proto, "REMOTEADDR", remote_addr);
+ if (option_mask32 & OPT_h) {
+ xsetenv_proto(proto, "LOCALHOST", local_hostname);
+ xsetenv_proto(proto, "REMOTEHOST", remote_hostname);
+ }
+ //compat? xsetenv_proto(proto, "REMOTEINFO", "");
+ /* additional */
+ if (cur_per_host > 0) /* can not be true for udp */
+ xsetenv_plain("TCPCONCURRENCY", utoa(cur_per_host));
+ }
+ free(local_addr);
+ free(free_me0);
+ free(free_me1);
+ free(free_me2);
+ }
+
+ xdup2(0, 1);
+
+ signal(SIGPIPE, SIG_DFL); /* this one was SIG_IGNed */
+ /* Non-ignored signals revert to SIG_DFL on exec anyway */
+ /*signal(SIGCHLD, SIG_DFL);*/
+ sig_unblock(SIGCHLD);
+
+#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.
+ * busybox accepts IPv6 addresses and host:port pairs too
+ In this case second parameter is ignored
+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.
+ * ignored by busyboxed version
+-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).
+ * ignored by busyboxed version
+-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.
+ * ignored by busyboxed version
+-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.
+ * ignored by busyboxed version
+-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.
+ * no difference between -v and -vv in busyboxed version
+*/