diff options
| -rw-r--r-- | lib/lib.h | 1 | ||||
| -rw-r--r-- | lib/net.c | 37 | ||||
| -rw-r--r-- | toys/net/netcat.c | 176 |
3 files changed, 114 insertions, 100 deletions
@@ -281,6 +281,7 @@ void xsetsockopt(int fd, int level, int opt, void *val, socklen_t len); int xconnect(char *host, char *port, int family, int socktype, int protocol, int flags); int xpoll(struct pollfd *fds, int nfds, int timeout); +int pollinate(int in1, int in2, int out1, int out2, int timeout, int shutdown_timeout); // password.c int get_salt(char *salt, char * algo); @@ -55,3 +55,40 @@ int xpoll(struct pollfd *fds, int nfds, int timeout) } else return i; } } + +// Loop forwarding data from in1 to out1 and in2 to out2, handling +// half-connection shutdown. timeouts return if no data for X miliseconds. +// Returns 0: both closed, 1 shutdown_timeout, 2 timeout +int pollinate(int in1, int in2, int out1, int out2, int timeout, int shutdown_timeout) +{ + struct pollfd pollfds[2]; + int i, pollcount = 2; + + memset(pollfds, 0, 2*sizeof(struct pollfd)); + pollfds[0].events = pollfds[1].events = POLLIN; + pollfds[0].fd = in1; + pollfds[1].fd = in2; + + // Poll loop copying data from each fd to the other one. + for (;;) { + if (!xpoll(pollfds, pollcount, timeout)) return pollcount; + + for (i=0; i<pollcount; i++) { + if (pollfds[i].revents & POLLIN) { + int len = read(pollfds[i].fd, libbuf, sizeof(libbuf)); + if (len<1) pollfds[i].revents = POLLHUP; + else xwrite(i ? out2 : out1, libbuf, len); + } + if (pollfds[i].revents & POLLHUP) { + // Close half-connection. This is needed for things like + // "echo GET / | netcat landley.net 80" + // Note that in1 closing triggers timeout, in2 returns now. + if (i) { + shutdown(pollfds[0].fd, SHUT_WR); + pollcount--; + timeout = shutdown_timeout; + } else return 0; + } + } + } +} diff --git a/toys/net/netcat.c b/toys/net/netcat.c index 1c75eb26..24420d6b 100644 --- a/toys/net/netcat.c +++ b/toys/net/netcat.c @@ -5,7 +5,7 @@ * TODO: udp, ipv6, genericize for telnet/microcom/tail-f USE_NETCAT(OLDTOY(nc, netcat, TOYFLAG_USR|TOYFLAG_BIN)) -USE_NETCAT(NEWTOY(netcat, USE_NETCAT_LISTEN("^tlL")"w#p#s:q#f:", TOYFLAG_BIN)) +USE_NETCAT(NEWTOY(netcat, USE_NETCAT_LISTEN("^tlL")"w#W#p#s:q#f:"USE_NETCAT_LISTEN("[!tlL][!Lw]"), TOYFLAG_BIN)) config NETCAT bool "netcat" @@ -15,9 +15,10 @@ config NETCAT -f use FILENAME (ala /dev/ttyS0) instead of network -p local port number - -q SECONDS quit this many seconds after EOF on stdin. - -s local ipv4 address - -w SECONDS timeout for connection + -q quit SECONDS after EOF on stdin, even if stdout hasn't closed yet. + -s local source address + -w SECONDS timeout to establish connection + -W SECONDS timeout for idle connection Use "stty 115200 -F /dev/ttyS0 && stty raw -echo -ctlecho" with netcat -f to connect to a serial port. @@ -26,28 +27,20 @@ config NETCAT_LISTEN bool "netcat server options (-let)" default y depends on NETCAT - depends on TOYBOX_FORK help - usage: netcat [-lL COMMAND...] + usage: netcat [-t] [-lL COMMAND...] - -l listen for one incoming connection. - -L listen for multiple incoming connections (server mode). + -l listen for one incoming connection + -L listen for multiple incoming connections (server mode) + -t allocate tty (must come before -l or -L) - The command line after -l or -L is executed to handle each incoming - connection. If none, the connection is forwarded to stdin/stdout. + The command line after -l or -L is executed (as a child process) to handle + each incoming connection. If blank -l waits for a connection and forwards + it to stdin/stdout. If no -p specified, -l prints port it bound to and + backgrounds itself (returning immediately). For a quick-and-dirty server, try something like: netcat -s 127.0.0.1 -p 1234 -tL /bin/bash -l - -config NETCAT_LISTEN_TTY - bool - default y - depends on NETCAT_LISTEN - depends on TOYBOX_FORK - help - usage: netcat [-t] - - -t allocate tty (must come before -l or -L) */ #define FOR_netcat @@ -58,6 +51,7 @@ GLOBALS( long quit_delay; // -q Exit after EOF from stdin after # seconds. char *source_address; // -s Bind to a specific source address. long port; // -p Bind to a specific source port. + long idle; // -W Wait # seconds for more data long wait; // -w Wait # seconds for a connection. ) @@ -92,36 +86,34 @@ static void lookup_port(char *str, uint16_t *port) void netcat_main(void) { - int sockfd=-1, pollcount=2; - struct pollfd pollfds[2]; + struct sockaddr_in *address = (void *)toybuf; + int sockfd=-1, in1 = 0, in2 = 0, out1 = 1, out2 = 1; + pid_t child; + + // Addjust idle and quit_delay to miliseconds or -1 for no timeout + TT.idle = TT.idle ? TT.idle*1000 : -1; + TT.quit_delay = TT.quit_delay ? TT.quit_delay*1000 : -1; - memset(pollfds, 0, 2*sizeof(struct pollfd)); - pollfds[0].events = pollfds[1].events = POLLIN; set_alarm(TT.wait); // The argument parsing logic can't make "<2" conditional on other // arguments like -f and -l, so we do it by hand here. if ((toys.optflags&FLAG_f) ? toys.optc : (!(toys.optflags&(FLAG_l|FLAG_L)) && toys.optc!=2)) - help_exit("Argument count wrong"); + help_exit("bad argument count"); - if (TT.filename) pollfds[0].fd = xopen(TT.filename, O_RDWR); + if (TT.filename) in1 = out2 = xopen(TT.filename, O_RDWR); else { - int temp; - struct sockaddr_in address; - // Setup socket sockfd = xsocket(AF_INET, SOCK_STREAM, 0); fcntl(sockfd, F_SETFD, FD_CLOEXEC); - temp = 1; - setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &temp, sizeof(temp)); - memset(&address, 0, sizeof(address)); - address.sin_family = AF_INET; + setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &out1, sizeof(out1)); + address->sin_family = AF_INET; if (TT.source_address || TT.port) { - address.sin_port = SWAP_BE16(TT.port); + address->sin_port = SWAP_BE16(TT.port); if (TT.source_address) - lookup_name(TT.source_address, (uint32_t *)&address.sin_addr); - if (bind(sockfd, (struct sockaddr *)&address, sizeof(address))) + lookup_name(TT.source_address, (uint32_t *)&(address->sin_addr)); + if (bind(sockfd, (struct sockaddr *)address, sizeof(*address))) perror_exit("bind"); } @@ -129,102 +121,86 @@ void netcat_main(void) if (!CFG_NETCAT_LISTEN || !(toys.optflags&(FLAG_L|FLAG_l))) { // Figure out where to dial out to. - lookup_name(*toys.optargs, (uint32_t *)&address.sin_addr); - lookup_port(toys.optargs[1], &address.sin_port); - temp = connect(sockfd, (struct sockaddr *)&address, sizeof(address)); - if (temp<0) perror_exit("connect"); - pollfds[0].fd = sockfd; + lookup_name(*toys.optargs, (uint32_t *)&(address->sin_addr)); + lookup_port(toys.optargs[1], &(address->sin_port)); +// TODO xconnect + if (connect(sockfd, (struct sockaddr *)address, sizeof(*address))<0) + perror_exit("connect"); + in1 = out2 = sockfd; // Listen for incoming connections } else { - socklen_t len = sizeof(address); + socklen_t len = sizeof(*address); if (listen(sockfd, 5)) error_exit("listen"); if (!TT.port) { - getsockname(sockfd, (struct sockaddr *)&address, &len); - printf("%d\n", SWAP_BE16(address.sin_port)); + getsockname(sockfd, (struct sockaddr *)address, &len); + printf("%d\n", SWAP_BE16(address->sin_port)); fflush(stdout); - } - // Do we need to return immediately because -l has arguments? - - if ((toys.optflags & FLAG_l) && toys.optc) { - if (CFG_TOYBOX_FORK && xfork()) goto cleanup; - close(0); - close(1); - close(2); + // Return immediately if no -p and -Ll has arguments, so wrapper + // script can use port number. + if (CFG_TOYBOX_FORK && toys.optc && xfork()) goto cleanup; } for (;;) { - pid_t child = 0; + child = 0; + len = sizeof(*address); // gcc's insane optimizer can overwrite this + in1 = out2 = accept(sockfd, (struct sockaddr *)address, &len); - // For -l, call accept from the _new_ process. + if (in1<0) perror_exit("accept"); - pollfds[0].fd = accept(sockfd, (struct sockaddr *)&address, &len); - if (pollfds[0].fd<0) perror_exit("accept"); + // We can't exit this loop or the optimizer's "liveness analysis" + // combines badly with vfork() to corrupt or local variables + // (the child's call stack gets trimmed and the next function call + // stops the variables the parent tries to re-use next loop) + // So there's a bit of redundancy here - // Do we need a tty? + // We have a connection. Disarm timeout. + set_alarm(0); - if (toys.optflags&FLAG_t) - child = forkpty(&(pollfds[1].fd), NULL, NULL, NULL); + if (toys.optc) { + // Do we need a tty? - // Do we need to fork and/or redirect for exec? +// TODO nommu, and -t only affects server mode...? Only do -t with optc +// if (CFG_TOYBOX_FORK && (toys.optflags&FLAG_t)) +// child = forkpty(&fdout, NULL, NULL, NULL); +// else + + // Do we need to fork and/or redirect for exec? - else { if (toys.optflags&FLAG_L) { toys.stacktop = 0; child = vfork(); } - if (!child && toys.optc) { - int fd = pollfds[0].fd; - - dup2(fd, 0); - dup2(fd, 1); - if (toys.optflags&FLAG_L) dup2(fd, 2); - if (fd>2) close(fd); + if (child<0) error_msg("vfork failed\n"); + else { + if (child) { + close(in1); + continue; + } + dup2(in1, 0); + dup2(in1, 1); + if (toys.optflags&FLAG_L) dup2(in1, 2); + if (in1>2) close(in1); + xexec(toys.optargs); } } - if (child<0) error_msg("Fork failed\n"); - if (child<1) break; - close(pollfds[0].fd); + pollinate(in1, in2, out1, out2, TT.idle, TT.quit_delay); + close(in1); } } } - // We have a connection. Disarm timeout. - // (Does not play well with -L, but what _should_ that do?) + // We have a connection. Disarm timeout. set_alarm(0); - if (CFG_NETCAT_LISTEN && ((toys.optflags&(FLAG_L|FLAG_l)) && toys.optc)) - xexec(toys.optargs); - - // Poll loop copying stdin->socket and socket->stdout. - for (;;) { - int i; - - if (0>poll(pollfds, pollcount, -1)) perror_exit("poll"); - - for (i=0; i<pollcount; i++) { - if (pollfds[i].revents & POLLIN) { - int len = read(pollfds[i].fd, toybuf, sizeof(toybuf)); - if (len<1) goto dohupnow; - xwrite(i ? pollfds[0].fd : 1, toybuf, len); - } else if (pollfds[i].revents & POLLHUP) { -dohupnow: - // Close half-connection. This is needed for things like - // "echo GET / | netcat landley.net 80" - if (i) { - shutdown(pollfds[0].fd, SHUT_WR); - pollcount--; - set_alarm(TT.quit_delay); - } else goto cleanup; - } - } - } + pollinate(in1, in2, out1, out2, TT.idle, TT.quit_delay); + cleanup: if (CFG_TOYBOX_FREE) { - close(pollfds[0].fd); + close(in1); close(sockfd); } } |