emo/busybox
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

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

Browse Source
This commit is contained in:
Denis Vlasenko 2007-04-03 01:13:04 +00:00
parent cea0a8bccb
commit 992e05b6f0
5 changed files with 320 additions and 60 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
include/libbb.h
View File

@ -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);

27
include/usage.h
View File

@ -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]"

5
ipsvd/tcpsvd.c
View File

@ -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);

156
ipsvd/udp_io.c Normal file
View File

@ -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
}

181
ipsvd/udpsvd.c
View File

@ -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.
*/