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-rw-r--r--ipsvd/tcpudp.c446
1 files changed, 120 insertions, 326 deletions
diff --git a/ipsvd/tcpudp.c b/ipsvd/tcpudp.c
index 419551d..6e8ec32 100644
--- a/ipsvd/tcpudp.c
+++ b/ipsvd/tcpudp.c
@@ -7,12 +7,51 @@
* Licensed under GPLv2, see file LICENSE in this tarball for details.
*/
-/* TCP and UDP server are using a lot of same string constants
- * We reuse them by keeping both in one source file */
+/* Based on ipsvd 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.
+ *
+ * Output of verbose mode matches original (modulo bugs and
+ * unimplemented stuff). Unnatural splitting of IP and PORT
+ * is retained (personally I prefer one-value "IP:PORT" notation -
+ * it is a natural string representation of struct sockaddr_XX).
+ *
+ * TCPORIGDST{IP,PORT} 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 reptrieved (using recvmsg voodoo) but
+ * child's socket is not bound to it (bind cannot be called on
+ * already bound socket). Thus you still can get outgoing packets
+ * with wrong sorce IP...
+ * - don't know how to retrieve ORIGDST for udp.
+ */
+
+#include <limits.h>
+#include <linux/netfilter_ipv4.h> /* wants <limits.h> */
#include "busybox.h"
+#include "udp_io.c"
+#include "ipsvd_perhost.h"
+
+#ifdef SSLSVD
+#include "matrixSsl.h"
+#include "ssl_io.h"
+#endif
+
static unsigned verbose;
+static unsigned max_per_host;
+static unsigned cur_per_host;
+static unsigned cnum;
+static unsigned cmax = 30;
+
+static void xsetenv_proto(const char *proto, const char *n, const char *v)
+{
+ putenv(xasprintf("%s%s=%s", proto, n, v));
+}
static void sig_term_handler(int sig)
{
@@ -38,287 +77,6 @@ static void print_waitstat(unsigned pid, int wstat)
printf("%s: info: end %d %s %d\n", applet_name, pid, cause, e);
}
-
-#if ENABLE_UDPSVD
-/* Based on ipsvd ipsvd-0.12.1. This udpsvd 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.
- *
- * Output of verbose mode matches original (modulo bugs and
- * unimplemented stuff). Unnatural splitting of IP and PORT
- * is retained (personally I prefer one-value "IP:PORT" notation -
- * it is a natural string representation of struct sockaddr_XX).
- */
-
-#include "udp_io.c"
-
-int udpsvd_main(int argc, char **argv);
-int udpsvd_main(int argc, char **argv)
-{
- const char *instructs;
- char *str_t, *user;
- unsigned opt;
-
- char *remote_hostname = (char*)""; /* used if no -h */
- char *local_hostname = NULL;
- char *remote_ip;
- char *local_ip;// = local_ip; /* gcc */
- uint16_t local_port, remote_port;
- len_and_sockaddr remote;
- len_and_sockaddr *localp;
- int wstat;
- unsigned pid;
- struct bb_uidgid_t ugid;
-
- enum {
- OPT_v = (1 << 0),
- OPT_u = (1 << 1),
- OPT_l = (1 << 2),
- OPT_h = (1 << 3),
- OPT_p = (1 << 4),
- OPT_i = (1 << 5),
- OPT_x = (1 << 6),
- OPT_t = (1 << 7),
- };
-
- opt_complementary = "-3:ph:vv";
- opt = getopt32(argc, argv, "vu:l:hpi:x:t:",
- &user, &local_hostname, &instructs, &instructs, &str_t, &verbose);
- if (opt & OPT_u) {
- if (!get_uidgid(&ugid, user, 1))
- bb_error_msg_and_die("unknown user/group: %s", user);
- }
- argv += optind;
- if (!argv[0][0] || LONE_CHAR(argv[0], '0'))
- argv[0] = (char*)"0.0.0.0";
-
- /* stdout is used for logging, don't buffer */
- setlinebuf(stdout);
- bb_sanitize_stdio(); /* fd# 1,2 must be opened */
-
- signal(SIGTERM, sig_term_handler);
- signal(SIGPIPE, SIG_IGN);
-
- local_port = bb_lookup_port(argv[1], "udp", 0);
- localp = xhost2sockaddr(argv[0], local_port);
- /* fd #0 is the open UDP socket */
- xmove_fd(xsocket(localp->sa.sa_family, SOCK_DGRAM, 0), 0);
- setsockopt_reuseaddr(0); /* crucial */
- xbind(0, &localp->sa, localp->len);
- socket_want_pktinfo(0); /* needed for recv_from_to to work */
-
- if (opt & OPT_u) { /* drop permissions */
- xsetgid(ugid.gid);
- xsetuid(ugid.uid);
- }
-
- if (verbose) {
- /* we do it only for ":port" cosmetics... oh well */
- char *addr = xmalloc_sockaddr2dotted(&localp->sa, localp->len);
-
- printf("%s: info: listening on %s", applet_name, addr);
- free(addr);
- if (option_mask32 & OPT_u)
- printf(", uid %u, gid %u",
- (unsigned)ugid.uid, (unsigned)ugid.gid);
- puts(", starting");
- }
-
- again:
- /* if (recvfrom(0, NULL, 0, MSG_PEEK, &remote.sa, &localp->len) < 0) { */
- if (recv_from_to(0, NULL, 0, MSG_PEEK, &remote.sa, &localp->sa, localp->len) < 0) {
- bb_perror_msg("recvfrom");
- goto again;
- }
-
- while ((pid = fork()) < 0) {
- bb_perror_msg("fork failed, sleeping");
- sleep(5);
- }
- if (pid > 0) { /* parent */
- while (wait_pid(&wstat, pid) < 0)
- bb_perror_msg("error waiting for child");
- if (verbose)
- print_waitstat(pid, wstat);
- goto again;
- }
-
- /* Child */
-
- if (verbose) {
- remote_ip = xmalloc_sockaddr2dotted_noport(&remote.sa, localp->len);
- local_ip = xmalloc_sockaddr2dotted_noport(&localp->sa, localp->len);
-
- pid = getpid();
- printf("%s: info: pid %u from %s\n", applet_name, pid, remote_ip);
-
- if (!local_hostname) {
- local_hostname = xmalloc_sockaddr2host_noport(&localp->sa, localp->len);
- if (!local_hostname)
- bb_error_msg_and_die("cannot look up local hostname for %s", local_ip);
- }
- if (opt & OPT_h) {
- remote_hostname = xmalloc_sockaddr2host(&remote.sa, localp->len);
- if (!remote_hostname) {
- bb_error_msg("warning: cannot look up hostname for %s", remote_ip);
- remote_hostname = (char*)"";
- }
- }
-
- remote_port = get_nport(&remote.sa);
- remote_port = ntohs(remote_port);
- printf("%s: info: %u %s:%s :%s:%s:%u\n",
- applet_name, pid, local_hostname, local_ip,
- remote_hostname, remote_ip, remote_port);
- }
-
- /* 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
- * do not expect data coming *from fd #1*! */
-#if 0
- /* Make it so that local addr is fixed to localp->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->sa.sa_family, SOCK_DGRAM, 0), 0);
- setsockopt_reuseaddr(0); /* crucial */
- xbind(0, &localp->sa, localp->len);
-#endif
-
- /* Make plain write to fd #1 work for the child by supplying default
- * destination address. This also restricts incoming packets
- * to ones coming from this remote IP. */
- xconnect(0, &remote.sa, localp->len);
- dup2(0 ,1);
-
- signal(SIGTERM, SIG_DFL);
- signal(SIGPIPE, SIG_DFL);
-
- argv += 2;
- BB_EXECVP(argv[0], argv);
- bb_perror_msg_and_die("exec '%s'", argv[0]);
-}
-
-
-/*
-udpsvd [-hpvv] [-u user] [-l name] [-i dir|-x cdb] [-t sec] host port prog
-
-udpsvd creates an UDP/IP socket, binds it to the address host:port,
-and listens on the socket for incoming datagrams.
-
-If a datagram is available on the socket, udpsvd conditionally starts
-a program, with standard input reading from the socket, and standard
-output redirected to standard error, to handle this, and possibly
-more datagrams. udpsvd does not start the program if another program
-that it has started before still is running. If the program exits,
-udpsvd again listens to the socket until a new datagram is available.
-If there are still datagrams available on the socket, the program
-is restarted immediately.
-
-udpsvd optionally checks for special intructions depending on
-the IP address or hostname of the client sending the datagram which
-not yet was handled by a running program, see ipsvd-instruct(5)
-for details.
-
-Attention:
-UDP is a connectionless protocol. Most programs that handle user datagrams,
-such as talkd(8), keep running after receiving a datagram, and process
-subsequent datagrams sent to the socket until a timeout is reached.
-udpsvd only checks special instructions for a datagram that causes a startup
-of the program; not if a program handling datagrams already is running.
-It doesn't make much sense to restrict access through special instructions
-when using such a program.
-
-On the other hand, it makes perfectly sense with programs like tftpd(8),
-that fork to establish a separate connection to the client when receiving
-the datagram. In general it's adequate to set up special instructions for
-programs that support being run by tcpwrapper.
-Options
-
-host
- host either is a hostname, or a dotted-decimal IP address, or 0.
- If host is 0, udpsvd accepts datagrams to any local IP address.
-port
- udpsvd accepts datagrams to host:port. port may be a name from
- /etc/services or a number.
-prog
- prog consists of one or more arguments. udpsvd normally runs prog
- to handle a datagram, and possibly more, that is sent to the socket,
- if there is no program that was started before by udpsvd still running
- and handling datagrams.
--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; udpsvd 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. By default udpsvd looks up the local hostname once at startup.
--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.
--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 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.
--v
- verbose. Print verbose messages to standard output.
--vv
- more verbose. Print more verbose messages to standard output.
-*/
-#endif
-
-
-#if ENABLE_TCPSVD
-/* Based on ipsvd 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.
- *
- * Output of verbose mode matches original (modulo bugs and
- * unimplemented stuff). Unnatural splitting of IP and PORT
- * is retained (personally I prefer one-value "IP:PORT" notation -
- * it is a natural string representation of struct sockaddr_XX).
- *
- * TCPORIGDST{IP,PORT} is busybox-specific addition
- */
-
-#include <limits.h>
-#include <linux/netfilter_ipv4.h> /* wants <limits.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 cnum;
-static unsigned cmax = 30;
-
/* Must match getopt32 in main! */
enum {
OPT_c = (1 << 0),
@@ -342,7 +100,9 @@ enum {
static void connection_status(void)
{
- printf("%s: info: status %u/%u\n", applet_name, cnum, cmax);
+ /* UDP and "only 1 client max" TCP don't need this */
+ if (cmax > 1)
+ printf("%s: info: status %u/%u\n", applet_name, cnum, cmax);
}
static void sig_child_handler(int sig)
@@ -362,8 +122,8 @@ static void sig_child_handler(int sig)
connection_status();
}
-int tcpsvd_main(int argc, char **argv);
-int tcpsvd_main(int argc, char **argv)
+int tcpudpsvd_main(int argc, char **argv);
+int tcpudpsvd_main(int argc, char **argv)
{
char *str_c, *str_C, *str_b, *str_t;
char *user;
@@ -372,11 +132,13 @@ int tcpsvd_main(int argc, char **argv)
char *msg_per_host = NULL;
unsigned len_per_host = len_per_host; /* gcc */
int need_hostnames, need_remote_ip;
+ int tcp;
int pid;
int sock;
int conn;
unsigned backlog = 20;
len_and_sockaddr *lsa;
+ len_and_sockaddr local, remote;
uint16_t local_port;
uint16_t remote_port = remote_port; /* gcc */
char *local_hostname = NULL;
@@ -386,6 +148,7 @@ int tcpsvd_main(int argc, char **argv)
#ifndef SSLSVD
struct bb_uidgid_t ugid;
#endif
+ tcp = (applet_name[0] == 't');
/* 3+ args, -i at most once, -p implies -h, -v is counter */
opt_complementary = "-3:?:i--i:ph:vv";
@@ -420,18 +183,22 @@ int tcpsvd_main(int argc, char **argv)
if (option_mask32 & OPT_b)
backlog = xatou(str_b);
#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;
+ 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;
+
/* stdout is used for logging, don't buffer */
setlinebuf(stdout);
- bb_sanitize_stdio(); /* fd# 1,2 must be opened */
+ bb_sanitize_stdio(); /* fd# 0,1,2 must be opened */
need_hostnames = verbose || !(option_mask32 & OPT_E);
need_remote_ip = max_per_host || need_hostnames;
@@ -473,12 +240,15 @@ int tcpsvd_main(int argc, char **argv)
if (max_per_host)
ipsvd_perhost_init(cmax);
- local_port = bb_lookup_port(argv[1], "tcp", 0);
+ local_port = bb_lookup_port(argv[1], tcp ? "tcp" : "udp", 0);
lsa = xhost2sockaddr(argv[0], local_port);
- sock = xsocket(lsa->sa.sa_family, SOCK_STREAM, 0);
- setsockopt_reuseaddr(sock); /* desirable */
+ sock = xsocket(lsa->sa.sa_family, tcp ? SOCK_STREAM : SOCK_DGRAM, 0);
+ setsockopt_reuseaddr(sock);
xbind(sock, &lsa->sa, lsa->len);
- xlisten(sock, backlog);
+ 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
@@ -503,7 +273,7 @@ int tcpsvd_main(int argc, char **argv)
puts(", starting");
}
- /* The rest is a main accept() loop */
+ /* Main accept() loop */
again:
hccp = NULL;
@@ -516,19 +286,23 @@ int tcpsvd_main(int argc, char **argv)
close(0);
again2:
sig_unblock(SIGCHLD);
- conn = accept(sock, &lsa->sa, &lsa->len);
+ if (tcp) {
+ remote.len = lsa->len;
+ conn = accept(sock, &remote.sa, &remote.len);
+ } else
+ conn = recv_from_to(sock, NULL, 0, MSG_PEEK, &remote.sa, &local.sa, lsa->len);
sig_block(SIGCHLD);
if (conn < 0) {
if (errno != EINTR)
- bb_perror_msg("accept");
+ bb_perror_msg(tcp ? "accept" : "recv");
goto again2;
}
- xmove_fd(conn, 0);
+ 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_ip = xmalloc_sockaddr2dotted_noport(&lsa->sa, lsa->len);
+ remote_ip = xmalloc_sockaddr2dotted_noport(&remote.sa, lsa->len);
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
@@ -543,17 +317,33 @@ int tcpsvd_main(int argc, char **argv)
}
}
- cnum++;
- if (verbose)
- connection_status();
+ if (!tcp) {
+ /* Voodoo magic: making udp sockets each receive its own
+ * packets is not trivial */
+
+ /* Make plain write work for this socket by supplying default
+ * destination address. This also restricts incoming packets
+ * to ones coming from this remote IP. */
+ xconnect(0, &remote.sa, lsa->len);
+ /* Open new non-connected UDP socket for further clients */
+ sock = xsocket(lsa->sa.sa_family, tcp ? SOCK_STREAM : SOCK_DGRAM, 0);
+ setsockopt_reuseaddr(sock);
+ xbind(sock, &lsa->sa, lsa->len);
+ socket_want_pktinfo(sock);
+ }
pid = fork();
if (pid == -1) {
bb_perror_msg("fork");
goto again;
}
+
+
if (pid != 0) {
/* parent */
+ cnum++;
+ if (verbose)
+ connection_status();
if (hccp)
hccp->pid = pid;
goto again;
@@ -561,35 +351,38 @@ int tcpsvd_main(int argc, char **argv)
/* Child: prepare env, log, and exec prog */
- close(sock); /* listening socket */
- /* Find out local IP peer connected to.
- * Errors ignored (I'm not paranoid enough to imagine kernel
- * which doesn't know local IP). */
- getsockname(0, &lsa->sa, &lsa->len);
+ /* Closing tcp listening socket */
+ if (tcp)
+ close(sock);
if (need_remote_ip) {
if (!max_per_host)
- remote_ip = xmalloc_sockaddr2dotted_noport(&lsa->sa, lsa->len);
+ remote_ip = xmalloc_sockaddr2dotted_noport(&remote.sa, lsa->len);
/* else it is already done */
- remote_port = get_nport(&lsa->sa);
+ remote_port = get_nport(&remote.sa);
remote_port = ntohs(remote_port);
}
if (need_hostnames) {
if (option_mask32 & OPT_h) {
- remote_hostname = xmalloc_sockaddr2host(&lsa->sa, lsa->len);
+ remote_hostname = xmalloc_sockaddr2host(&remote.sa, lsa->len);
if (!remote_hostname) {
bb_error_msg("warning: cannot look up hostname for %s", remote_ip);
remote_hostname = (char*)"";
}
}
- local_ip = xmalloc_sockaddr2dotted_noport(&lsa->sa, lsa->len);
- local_port = get_nport(&lsa->sa);
+ /* 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.sa, &local.len);
+ local_ip = xmalloc_sockaddr2dotted_noport(&local.sa, lsa->len);
+ local_port = get_nport(&local.sa);
local_port = ntohs(local_port);
if (!local_hostname) {
- local_hostname = xmalloc_sockaddr2host_noport(&lsa->sa, lsa->len);
+ local_hostname = xmalloc_sockaddr2host_noport(&local.sa, lsa->len);
if (!local_hostname)
- bb_error_msg_and_die("cannot look up local hostname for %s", local_ip);
+ bb_error_msg_and_die("warning: cannot look up hostname for %s"+9, local_ip);
}
}
@@ -605,14 +398,16 @@ int tcpsvd_main(int argc, char **argv)
remote_hostname, remote_ip, (unsigned)remote_port);
}
+// TODO: stop splitiing port# from IP?
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 (getsockopt(0, SOL_IP, SO_ORIGINAL_DST, &lsa->sa, &lsa->len) == 0) {
+ if (tcp && getsockopt(0, SOL_IP, SO_ORIGINAL_DST, &lsa->sa, &lsa->len) == 0) {
char *ip = xmalloc_sockaddr2dotted_noport(&lsa->sa, lsa->len);
unsigned port = get_nport(&lsa->sa);
port = ntohs(port);
@@ -620,18 +415,18 @@ int tcpsvd_main(int argc, char **argv)
xsetenv("TCPORIGDSTPORT", utoa(port));
free(ip);
}
- 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));
+ xsetenv("PROTO", proto);
+ xsetenv_proto(proto, "LOCALIP", local_ip);
+ xsetenv_proto(proto, "LOCALPORT", utoa(local_port));
+ xsetenv_proto(proto, "LOCALHOST", local_hostname);
+ xsetenv_proto(proto, "REMOTEIP", remote_ip);
+ xsetenv_proto(proto, "REMOTEPORT", utoa(remote_port));
if (option_mask32 & OPT_h) {
- xsetenv("TCPREMOTEHOST", remote_hostname);
+ xsetenv_proto(proto, "REMOTEHOST", remote_hostname);
}
- xsetenv("TCPREMOTEINFO", "");
+ xsetenv_proto(proto, "REMOTEINFO", "");
/* additional */
- if (cur_per_host > 0)
+ if (cur_per_host > 0) /* can not be true for udp */
xsetenv("TCPCONCURRENCY", utoa(cur_per_host));
}
@@ -747,4 +542,3 @@ prog
more verbose. Print more verbose messages to standard output.
* no difference between -v and -vv in busyboxed version
*/
-#endif