← Commit list

992e05b6f

Denis Vlasenko

2007-04-03

FAILED Duration: 15s

Subject

udpsvd: more work on it. works in limited testing.

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

include/libbb.h +11 -0 include/usage.h +18 -9 ipsvd/tcpsvd.c +4 -1 ipsvd/udp_io.c +156 -0 ipsvd/udpsvd.c +131 -50

include/libbb.h+11 -0

@@ -321,6 +321,17 @@ typedef struct len_and_sockaddr {
	#endif
	};
	} len_and_sockaddr;
+	enum {
+	LSA_SIZEOF_SA = sizeof(
+	union {
+	struct sockaddr sa;
+	struct sockaddr_in sin;
+	#if ENABLE_FEATURE_IPV6
+	struct sockaddr_in6 sin6;
+	#endif
+	}
+	)
+	};
	/* Create stream socket, and allocated suitable lsa
	* (lsa of correct size and lsa->sa.sa_family (AF_INET/AF_INET6)) */
	int xsocket_stream(len_and_sockaddr **lsap);

include/usage.h+18 -9

@@ -3326,32 +3326,41 @@ USE_FEATURE_RUN_PARTS_FANCY("\n -l Prints names of all matching files even when
	"1\n"

	#define tcpsvd_trivial_usage \
-	"[-hpEvv] [-c n] [-C n:msg] [-b n] [-u user] [-l name] ip port prog..."
+	"[-hEv] [-c n] [-C n:msg] [-b n] [-u user] [-l name] ip port prog..."
	/* with not-implemented options: */
	/* "[-hpEvv] [-c n] [-C n:msg] [-b n] [-u user] [-l name] [-i dir\|-x cdb] [ -t sec] ip port prog..." */
	#define tcpsvd_full_usage \
-	"tcpsvd creates TCP/IP socket, binds it to host:port\n" \
-	"and listens on in for incoming connections. For each connection\n" \
-	"it runs prog" \
+	"Creates TCP socket, binds it to host:port and listens on in\n" \
+	"for incoming connections. For each connection it runs prog" \
	"\n" \
-	"\nip IP to listen on. '0' = 'all'" \
+	"\nip IP to listen on. '0' = all" \
	"\nport Port to listen on" \
-	"\nprog [arg] Program to run for each connection" \
+	"\nprog [arg] Program to run" \
	"\n-l name Local hostname (else looks up local hostname in DNS)" \
	"\n-u user[:group] Change to user/group after bind" \
	"\n-c n Handle up to n connections simultaneously" \
	"\n-C n[:msg] Allow only up to n connections from the same IP" \
	"\n New connections from this IP address are closed" \
	"\n immediately. 'msg' is written to the peer before close" \
-	"\n-h Look up peer's hostname in DNS" \
+	"\n-h Look up peer's hostname" \
	"\n-b n Allow a backlog of approximately n TCP SYNs" \
	"\n-E Do not set up TCP-related environment variables" \
	"\n-v Verbose"

	#define udpsvd_trivial_usage \
-	"TODO"
+	"[-hv] [-u user] [-l name] host port prog"
	#define udpsvd_full_usage \
-	"TODO"
+	"Creates UDP socket, binds it to host:port and listens on in\n" \
+	"for incoming packets. When packet arrives it runs prog.\n" \
+	"When prog exits, it start to listen on the socket again" \
+	"\n" \
+	"\nip IP to listen on. '0' = all" \
+	"\nport Port to listen on" \
+	"\nprog [arg] Program to run" \
+	"\n-l name Local hostname (else looks up local hostname in DNS)" \
+	"\n-u user[:group] Change to user/group after bind" \
+	"\n-h Look up peer's hostname" \
+	"\n-v Verbose"

	#define tftp_trivial_usage \
	"[OPTION]... HOST [PORT]"

ipsvd/tcpsvd.c+4 -1

@@ -179,7 +179,10 @@ int tcpsvd_main(int argc, char **argv)
	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 */
+
	need_hostnames = verbose \|\| !(option_mask32 & OPT_E);
	need_remote_ip = max_per_host \|\| need_hostnames;

@@ -232,7 +235,6 @@ int tcpsvd_main(int argc, char **argv)
	xsetuid(ugid.uid);
	}
	#endif
-	bb_sanitize_stdio(); /* fd# 1,2 must be opened */
	close(0);

	if (verbose) {
@@ -439,6 +441,7 @@ int tcpsvd_main(int argc, char **argv)

	xmove_fd(conn, 0);
	dup2(0, 1);
+
	signal(SIGTERM, SIG_DFL);
	signal(SIGPIPE, SIG_DFL);
	signal(SIGCHLD, SIG_DFL);

ipsvd/udp_io.c+156 -0

@@ -0,0 +1,156 @@
+	/* Thus far used only by udpsvd.c */
+
+	void socket_want_pktinfo(int fd);
+	ssize_t send_to_from(int fd, void *buf, size_t len, int flags,
+	const struct sockaddr from, const struct sockaddr to,
+	socklen_t tolen);
+	ssize_t recv_from_to(int fd, void *buf, size_t len, int flags,
+	struct sockaddr from, struct sockaddr to,
+	socklen_t sa_size);
+
+	/*
+	* This asks kernel to let us know dst addr/port of incoming packets
+	* We don't check for errors here. Not supported == won't be used
+	*/
+	void
+	socket_want_pktinfo(int fd)
+	{
+	#ifdef IP_PKTINFO
+	setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &const_int_1, sizeof(int));
+	#endif
+	#ifdef IPV6_PKTINFO
+	setsockopt(fd, IPPROTO_IPV6, IPV6_PKTINFO, &const_int_1, sizeof(int));
+	#endif
+	}
+
+
+	ssize_t
+	send_to_from(int fd, void *buf, size_t len, int flags,
+	const struct sockaddr from, const struct sockaddr to,
+	socklen_t tolen)
+	{
+	#ifndef IP_PKTINFO
+	return sendto(fd, buf, len, flags, to, tolen);
+	#else
+	struct iovec iov[1];
+	struct msghdr msg;
+	char cbuf[LSA_SIZEOF_SA];
+	/* actually, max(sizeof(in_pktinfo),sizeof(in6_pktinfo)) */
+	struct cmsghdr* cmsgptr;
+
+	if (from->sa_family != AF_INET
+	#if ENABLE_FEATURE_IPV6
+	&& from->sa_family != AF_INET6
+	#endif
+	) {
+	/* ANY local address */
+	return sendto(fd, buf, len, flags, to, tolen);
+	}
+
+	/* man recvmsg and man cmsg is needed to make sense of code below */
+
+	iov[0].iov_base = buf;
+	iov[0].iov_len = len;
+
+	memset(cbuf, 0, sizeof(cbuf));
+
+	memset(&msg, 0, sizeof(msg));
+	msg.msg_name = (void )(struct sockaddr )to; /* or compiler will annoy us */
+	msg.msg_namelen = tolen;
+	msg.msg_iov = iov;
+	msg.msg_iovlen = 1;
+	msg.msg_control = cbuf;
+	msg.msg_controllen = sizeof(cbuf);
+	msg.msg_flags = flags;
+
+	cmsgptr = CMSG_FIRSTHDR(&msg);
+	if (to->sa_family == AF_INET && from->sa_family == AF_INET) {
+	struct in_pktinfo *pktptr;
+	cmsgptr->cmsg_level = IPPROTO_IP;
+	cmsgptr->cmsg_type = IP_PKTINFO;
+	cmsgptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
+	pktptr = (struct in_pktinfo *)(CMSG_DATA(cmsgptr));
+	/* pktptr->ipi_ifindex = 0; -- already done by memset(cbuf...) */
+	pktptr->ipi_spec_dst = ((struct sockaddr_in*)from)->sin_addr;
+	}
+	#if ENABLE_FEATURE_IPV6 && defined(IP6_PKTINFO)
+	else if (to->sa_family == AF_INET6 && from->sa_family == AF_INET6) {
+	struct in6_pktinfo *pktptr;
+	cmsgptr->cmsg_level = IPPROTO_IPV6;
+	cmsgptr->cmsg_type = IP6_PKTINFO;
+	cmsgptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
+	pktptr = (struct in6_pktinfo *)(CMSG_DATA(cmsgptr));
+	/* pktptr->ipi6_ifindex = 0; -- already done by memset(cbuf...) */
+	pktptr->ipi6_addr = ((struct sockaddr_in6*)from)->sin6_addr;
+	}
+	#endif
+	return sendmsg(fd, &msg, flags);
+	#endif
+	}
+
+	/* NB: this will never set port# in to! /
+	ssize_t
+	recv_from_to(int fd, void *buf, size_t len, int flags,
+	struct sockaddr from, struct sockaddr to,
+	socklen_t sa_size)
+	{
+	#ifndef IP_PKTINFO
+	return recvfrom(fd, buf, len, flags, from, &sa_size);
+	#else
+	/* man recvmsg and man cmsg is needed to make sense of code below */
+	struct iovec iov[1];
+	union {
+	char cmsg[CMSG_SPACE(sizeof(struct in_pktinfo))];
+	char cmsg6[CMSG_SPACE(sizeof(struct in6_pktinfo))];
+	} u;
+	struct cmsghdr *cmsgptr;
+	struct msghdr msg;
+	socklen_t recv_length;
+
+	iov[0].iov_base = buf;
+	iov[0].iov_len = len;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.msg_name = (struct sockaddr *)from;
+	msg.msg_namelen = sa_size;
+	msg.msg_iov = iov;
+	msg.msg_iovlen = 1;
+	msg.msg_control = &u;
+	msg.msg_controllen = sizeof(u);
+
+	recv_length = recvmsg(fd, &msg, flags);
+	if (recv_length < 0)
+	return recv_length;
+
+	/* Here we try to retrieve destination IP and memorize it */
+	memset(to, 0, sa_size);
+	for (cmsgptr = CMSG_FIRSTHDR(&msg);
+	cmsgptr != NULL;
+	cmsgptr = CMSG_NXTHDR(&msg, cmsgptr)
+	) {
+	if (cmsgptr->cmsg_level == IPPROTO_IP
+	&& cmsgptr->cmsg_type == IP_PKTINFO
+	) {
+	#define pktinfo(cmsgptr) ( (struct in_pktinfo*)(CMSG_DATA(cmsgptr)) )
+	to->sa_family = AF_INET;
+	((struct sockaddr_in*)to)->sin_addr = pktinfo(cmsgptr)->ipi_addr;
+	/* ((struct sockaddr_in)to)->sin_port = 123; /
+	#undef pktinfo
+	break;
+	}
+	#if ENABLE_FEATURE_IPV6 && defined(IP6_PKTINFO)
+	if (cmsgptr->cmsg_level == IPPROTO_IPV6
+	&& cmsgptr->cmsg_type == IP6_PKTINFO
+	) {
+	#define pktinfo(cmsgptr) ( (struct in6_pktinfo*)(CMSG_DATA(cmsgptr)) )
+	to->sa_family = AF_INET6;
+	((struct sockaddr_in6*)to)->sin6_addr = pktinfo(cmsgptr)->ipi6_addr;
+	/* ((struct sockaddr_in6)to)->sin6_port = 123; /
+	#undef pktinfo
+	break;
+	}
+	#endif
+	}
+	return recv_length;
+	#endif
+	}

ipsvd/udpsvd.c+131 -50

@@ -22,12 +22,14 @@

	#include "busybox.h"

+	#include "udp_io.c"
+
	unsigned verbose;

	static void sig_term_handler(int sig)
	{
	if (verbose)
-	printf("udpsvd: info: sigterm received, exit\n");
+	printf("%s: info: sigterm received, exit\n", applet_name);
	exit(0);
	}

@@ -37,21 +39,14 @@ int udpsvd_main(int argc, char **argv)
	const char *instructs;
	char str_t, user;
	unsigned opt;
-	// unsigned lookuphost = 0;
-	// unsigned paranoid = 0;
-	// unsigned long timeout = 0;

	char *remote_hostname;
-	char local_hostname = local_hostname; / gcc */
+	char *local_hostname = NULL;
	char *remote_ip;
	char local_ip = local_ip; / gcc */
	uint16_t local_port, remote_port;
-	union {
-	struct sockaddr sa;
-	struct sockaddr_in sin;
-	USE_FEATURE_IPV6(struct sockaddr_in6 sin6;)
-	} sock_adr;
-	socklen_t sockadr_size;
+	len_and_sockaddr remote;
+	len_and_sockaddr *localp;
	int sock;
	int wstat;
	unsigned pid;
@@ -68,7 +63,7 @@ int udpsvd_main(int argc, char **argv)
	OPT_t = (1 << 7),
	};

-	opt_complementary = "ph:vv";
+	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_x) iscdb =1;
@@ -83,26 +78,29 @@ int udpsvd_main(int argc, char **argv)
	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);
-	sock = create_and_bind_dgram_or_die(argv[0], local_port);
+	localp = xhost2sockaddr(argv[0], local_port);
+	sock = xsocket(localp->sa.sa_family, SOCK_DGRAM, 0);
+	xmove_fd(sock, 0); /* fd# 0 is the open UDP socket */
+	xbind(0, &localp->sa, localp->len);
+	socket_want_pktinfo(0);

	if (opt & OPT_u) { /* drop permissions */
	xsetgid(ugid.gid);
	xsetuid(ugid.uid);
	}
-	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], local_port);
-	char *addr = xmalloc_sockaddr2dotted(&lsa->sa, lsa->len);
-	printf("udpsvd: info: listening on %s", addr);
+	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",
@@ -111,19 +109,8 @@ int udpsvd_main(int argc, char **argv)
	}

	again:
-	/* io[0].fd = s;
-	io[0].events = IOPAUSE_READ;
-	io[0].revents = 0;
-	taia_now(&now);
-	taia_uint(&deadline, 3600);
-	taia_add(&deadline, &now, &deadline);
-	iopause(io, 1, &deadline, &now);
-	if (!(io[0].revents \| IOPAUSE_READ))
-	goto again;
-	io[0].revents = 0;
-	*/
-	sockadr_size = sizeof(sock_adr);
-	if (recvfrom(sock, NULL, 0, MSG_PEEK, &sock_adr.sa, &sockadr_size) == -1) {
+	/* 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;
	}
@@ -136,28 +123,38 @@ int udpsvd_main(int argc, char **argv)
	while (wait_pid(&wstat, pid) == -1)
	bb_perror_msg("error waiting for child");
	if (verbose)
-	printf("udpsvd: info: end %u\n", pid);
+	printf("%s: info: end %u\n", applet_name, pid);
	goto again;
	}

	/* Child */

-	/* if (recvfrom(sock, 0, 0, MSG_PEEK, (struct sockaddr *)&sock_adr, &sockadr_size) == -1)
-	drop("unable to read from socket");
-	*/
+	#if 0
+	/* I'd like to make it so that local addr is fixed to localp->sa,
+	* but how? The below trick doesn't work... */
+	close(0);
+	set_nport(localp, htons(local_port));
+	xmove_fd(xsocket(localp->sa.sa_family, SOCK_DGRAM, 0), 0);
+	xbind(0, &localp->sa, localp->len);
+	#endif
+
	if (verbose) {
-	local_ip = argv[0]; // TODO: recv_from_to!
-	local_hostname = (char*)"localhost";
+	local_ip = xmalloc_sockaddr2dotted_noport(&localp->sa, localp->len);
+	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);
+	}
	}

-	remote_ip = xmalloc_sockaddr2dotted_noport(&sock_adr.sa, sockadr_size);
-	remote_port = get_nport(&sock_adr.sa);
+	remote_ip = xmalloc_sockaddr2dotted_noport(&remote.sa, localp->len);
+	remote_port = get_nport(&remote.sa);
	remote_port = ntohs(remote_port);
-	if (verbose) {
-	printf("udpsvd: info: pid %u from %s\n", pid, remote_ip);
-	}
+	if (verbose)
+	printf("%s: info: pid %u from %s\n", applet_name, pid, remote_ip);
+
	if (opt & OPT_h) {
-	remote_hostname = xmalloc_sockaddr2host(&sock_adr.sa, sizeof(sock_adr));
+	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*)"";
@@ -176,15 +173,15 @@ int udpsvd_main(int argc, char **argv)

	if (verbose) {
	#if 0
-	out("udpsvd: info: ");
+	out("%s: info: ", applet_name);
	switch(ac) {
	case IPSVD_DENY: out("deny "); break;
	case IPSVD_DEFAULT: case IPSVD_INSTRUCT: out("start "); break;
	case IPSVD_EXEC: out("exec "); break;
	}
	#endif
-	printf("udpsvd: info: %u %s:%s :%s:%s:%u\n",
-	pid, local_hostname, local_ip,
+	printf("%s: info: %u %s:%s :%s:%s:%u\n",
+	applet_name, pid, local_hostname, local_ip,
	remote_hostname, remote_ip, remote_port);
	#if 0
	if (instructs) {
@@ -202,7 +199,7 @@ int udpsvd_main(int argc, char **argv)

	#if 0
	if (ac == IPSVD_DENY) {
-	recv(s, 0, 0, 0);
+	recv(0, 0, 0, 0);
	_exit(100);
	}
	if (ac == IPSVD_EXEC) {
@@ -213,14 +210,98 @@ int udpsvd_main(int argc, char **argv)
	run = args;
	} else run = prog;
	#endif
-
-	xmove_fd(sock, 0);
+	/* Make plain write(1) work for the child by supplying default
+	* destination address */
+	xconnect(0, &remote.sa, localp->len);
	dup2(0, 1);

	signal(SIGTERM, SIG_DFL);
	signal(SIGPIPE, SIG_DFL);
-	argv += 2;

+	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.
+	*/