diff options
| -rw-r--r-- | ipsvd/Kbuild | 4 | ||||
| -rw-r--r-- | ipsvd/tcpudp.c (renamed from ipsvd/tcpsvd.c) | 498 | ||||
| -rw-r--r-- | ipsvd/udpsvd.c | 307 |
3 files changed, 349 insertions, 460 deletions
diff --git a/ipsvd/Kbuild b/ipsvd/Kbuild index 9eda63d..fc34fea 100644 --- a/ipsvd/Kbuild +++ b/ipsvd/Kbuild @@ -5,5 +5,5 @@ # Licensed under the GPL v2, see the file LICENSE in this tarball. lib-y:= -lib-$(CONFIG_TCPSVD) += tcpsvd.o ipsvd_perhost.o -lib-$(CONFIG_UDPSVD) += udpsvd.o +lib-$(CONFIG_TCPSVD) += tcpudp.o ipsvd_perhost.o +lib-$(CONFIG_UDPSVD) += tcpudp.o ipsvd_perhost.o diff --git a/ipsvd/tcpsvd.c b/ipsvd/tcpudp.c index 056deff..419551d 100644 --- a/ipsvd/tcpsvd.c +++ b/ipsvd/tcpudp.c @@ -7,13 +7,295 @@ * 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 */ + +#include "busybox.h" + +static unsigned verbose; + +static void sig_term_handler(int sig) +{ + if (verbose) + printf("%s: info: sigterm received, exit\n", applet_name); + exit(0); +} + +/* 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); + } + 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. - * Code inside #if 0" is parts of original tcpsvd which are not implemented - * for busyboxed version. * * Output of verbose mode matches original (modulo bugs and * unimplemented stuff). Unnatural splitting of IP and PORT @@ -25,7 +307,6 @@ #include <limits.h> #include <linux/netfilter_ipv4.h> /* wants <limits.h> */ -#include "busybox.h" #include "ipsvd_perhost.h" #ifdef SSLSVD @@ -33,10 +314,8 @@ #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; @@ -66,13 +345,6 @@ 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; @@ -83,22 +355,8 @@ static void sig_child_handler(int sig) 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) + print_waitstat(pid, wstat); } if (verbose) connection_status(); @@ -118,20 +376,13 @@ int tcpsvd_main(int argc, char **argv) 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; + len_and_sockaddr *lsa; + uint16_t local_port; + uint16_t remote_port = remote_port; /* gcc */ char *local_hostname = NULL; char *remote_hostname = (char*)""; /* "" used if no -h */ char *local_ip = local_ip; /* gcc */ char *remote_ip = remote_ip; /* gcc */ - //unsigned iscdb = 0; /* = option_mask32 & OPT_x (TODO) */ - //unsigned long timeout = 0; #ifndef SSLSVD struct bb_uidgid_t ugid; #endif @@ -168,7 +419,6 @@ int tcpsvd_main(int argc, char **argv) } 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; @@ -224,7 +474,10 @@ int tcpsvd_main(int argc, char **argv) ipsvd_perhost_init(cmax); local_port = bb_lookup_port(argv[1], "tcp", 0); - sock = create_and_bind_stream_or_die(argv[0], local_port); + lsa = xhost2sockaddr(argv[0], local_port); + sock = xsocket(lsa->sa.sa_family, SOCK_STREAM, 0); + setsockopt_reuseaddr(sock); /* desirable */ + xbind(sock, &lsa->sa, lsa->len); xlisten(sock, backlog); /* ndelay_off(sock); - it is the default I think? */ @@ -235,11 +488,9 @@ int tcpsvd_main(int argc, char **argv) xsetuid(ugid.uid); } #endif - 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("%s: info: listening on %s", applet_name, addr); @@ -260,32 +511,35 @@ int tcpsvd_main(int argc, char **argv) while (cnum >= cmax) sig_pause(); /* wait for any signal (expecting SIGCHLD) */ - sockadr_size = sizeof(sock_adr); + /* Accept a connection to fd #0 */ + again1: + close(0); + again2: sig_unblock(SIGCHLD); - conn = accept(sock, &sock_adr.sa, &sockadr_size); + conn = accept(sock, &lsa->sa, &lsa->len); sig_block(SIGCHLD); - if (conn == -1) { + if (conn < 0) { if (errno != EINTR) bb_perror_msg("accept"); - goto again; + goto again2; } + xmove_fd(conn, 0); if (max_per_host) { - /* we drop connection immediately if cur_per_host > max_per_host + /* Drop connection immediately if cur_per_host > max_per_host * (minimizing load under SYN flood) */ - remote_ip = xmalloc_sockaddr2dotted_noport(&sock_adr.sa, sockadr_size); + remote_ip = xmalloc_sockaddr2dotted_noport(&lsa->sa, lsa->len); cur_per_host = ipsvd_perhost_add(remote_ip, max_per_host, &hccp); if (cur_per_host > max_per_host) { - free(remote_ip); /* ipsvd_perhost_add detected that max is exceeded - * (and did not store us in connection table) */ + * (and did not store ip in connection table) */ + free(remote_ip); if (msg_per_host) { - ndelay_on(conn); - /* don't test for errors */ - write(conn, msg_per_host, len_per_host); + /* don't block or test for errors */ + ndelay_on(0); + write(0, msg_per_host, len_per_host); } - close(conn); - goto again; + goto again1; } } @@ -296,12 +550,10 @@ int tcpsvd_main(int argc, char **argv) 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; @@ -309,44 +561,50 @@ int tcpsvd_main(int argc, char **argv) /* Child: prepare env, log, and exec prog */ - close(sock); - - if (!max_per_host && need_remote_ip) - 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_hostnames && (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*)""; - } + 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); + + if (need_remote_ip) { + if (!max_per_host) + remote_ip = xmalloc_sockaddr2dotted_noport(&lsa->sa, lsa->len); + /* else it is already done */ + remote_port = get_nport(&lsa->sa); + remote_port = ntohs(remote_port); } - 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_hostnames) { - local_ip = xmalloc_sockaddr2dotted_noport(&sock_adr.sa, sockadr_size); - local_port = get_nport(&sock_adr.sa); + if (option_mask32 & OPT_h) { + remote_hostname = xmalloc_sockaddr2host(&lsa->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); local_port = ntohs(local_port); if (!local_hostname) { - local_hostname = xmalloc_sockaddr2host_noport(&sock_adr.sa, sockadr_size); + local_hostname = xmalloc_sockaddr2host_noport(&lsa->sa, lsa->len); if (!local_hostname) bb_error_msg_and_die("cannot look up local hostname for %s", local_ip); } } + if (verbose) { + pid = getpid(); + printf("%s: info: pid %u from %s\n", applet_name, pid, remote_ip); + if (max_per_host) + printf("%s: info: concurrency %u %s %u/%u\n", + applet_name, pid, remote_ip, cur_per_host, max_per_host); + 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 (!(option_mask32 & OPT_E)) { /* setup ucspi env */ @@ -354,10 +612,9 @@ int tcpsvd_main(int argc, char **argv) * from Linux firewall. Useful when you redirect * an outbond connection to local handler, and it needs * to know where it originally tried to connect */ - sockadr_size = sizeof(sock_adr); - if (getsockopt(conn, SOL_IP, SO_ORIGINAL_DST, &sock_adr.sa, &sockadr_size) == 0) { - char *ip = xmalloc_sockaddr2dotted_noport(&sock_adr.sa, sockadr_size); - unsigned port = get_nport(&sock_adr.sa); + if (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); xsetenv("TCPORIGDSTIP", ip); xsetenv("TCPORIGDSTPORT", utoa(port)); @@ -378,68 +635,6 @@ int tcpsvd_main(int argc, char **argv) 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); @@ -552,3 +747,4 @@ prog more verbose. Print more verbose messages to standard output. * no difference between -v and -vv in busyboxed version */ +#endif diff --git a/ipsvd/udpsvd.c b/ipsvd/udpsvd.c deleted file mode 100644 index 700e1af..0000000 --- a/ipsvd/udpsvd.c +++ /dev/null @@ -1,307 +0,0 @@ -/* 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 Denis Vlasenko. - * - * Licensed under GPLv2, see file LICENSE in this tarball for details. - */ - -/* 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 #if 0" is parts of original tcpsvd which are not implemented - * for busyboxed version. - * - * 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 "busybox.h" - -#include "udp_io.c" - -unsigned verbose; - -static void sig_term_handler(int sig) -{ - if (verbose) - printf("%s: info: sigterm received, exit\n", applet_name); - exit(0); -} - -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 *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 sock; - 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_x) iscdb =1; - //if (opt & OPT_t) timeout = xatou(str_t); - if (!(opt & OPT_h)) - remote_hostname = (char *)""; - 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); - 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); - } - - 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) == -1) - bb_perror_msg("error waiting for child"); - if (verbose) - printf("%s: info: end %u\n", applet_name, pid); - goto again; - } - - /* Child */ - -#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 = 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(&remote.sa, localp->len); - remote_port = get_nport(&remote.sa); - remote_port = ntohs(remote_port); - if (verbose) - printf("%s: info: pid %u from %s\n", applet_name, pid, remote_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*)""; - } - } - -#if 0 - if (instructs) { - ac = ipsvd_check(iscdb, &inst, &match, (char*)instructs, - remote_ip, remote_hostname.s, timeout); - if (ac == -1) discard("unable to check inst", remote_ip); - if (ac == IPSVD_ERR) discard("unable to read", (char*)instructs); - } else - ac = IPSVD_DEFAULT; -#endif - - if (verbose) { -#if 0 - 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("%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) { - out(" "); - if (iscdb) { - out((char*)instructs); out("/"); - } - outfix(match.s); - if(inst.s && inst.len && (verbose > 1)) { - out(": "); outinst(&inst); - } - } -#endif - } - -#if 0 - if (ac == IPSVD_DENY) { - recv(0, 0, 0, 0); - _exit(100); - } - if (ac == IPSVD_EXEC) { - args[0] = "/bin/sh"; - args[1] = "-c"; - args[2] = inst.s; - args[3] = NULL; - run = args; - } else run = prog; -#endif - /* 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; - 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. -*/ |