/* vi: set sw=4 ts=4: */ /* * A simple tftp client/server for busybox. * Tries to follow RFC1350. * Only "octet" mode supported. * Optional blocksize negotiation (RFC2347 + RFC2348) * * Copyright (C) 2001 Magnus Damm * * Parts of the code based on: * * atftp: Copyright (C) 2000 Jean-Pierre Lefebvre * and Remi Lefebvre * * utftp: Copyright (C) 1999 Uwe Ohse * * tftpd added by Denys Vlasenko & Vladimir Dronnikov * * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ //usage:#define tftp_trivial_usage //usage: "[OPTIONS] HOST [PORT]" //usage:#define tftp_full_usage "\n\n" //usage: "Transfer a file from/to tftp server\n" //usage: "\nOptions:" //usage: "\n -l FILE Local FILE" //usage: "\n -r FILE Remote FILE" //usage: IF_FEATURE_TFTP_GET( //usage: "\n -g Get file" //usage: ) //usage: IF_FEATURE_TFTP_PUT( //usage: "\n -p Put file" //usage: ) //usage: IF_FEATURE_TFTP_BLOCKSIZE( //usage: "\n -b SIZE Transfer blocks of SIZE octets" //usage: ) //usage: //usage:#define tftpd_trivial_usage //usage: "[-cr] [-u USER] [DIR]" //usage:#define tftpd_full_usage "\n\n" //usage: "Transfer a file on tftp client's request\n" //usage: "\n" //usage: "tftpd should be used as an inetd service.\n" //usage: "tftpd's line for inetd.conf:\n" //usage: " 69 dgram udp nowait root tftpd tftpd /files/to/serve\n" //usage: "It also can be ran from udpsvd:\n" //usage: " udpsvd -vE 0.0.0.0 69 tftpd /files/to/serve\n" //usage: "\nOptions:" //usage: "\n -r Prohibit upload" //usage: "\n -c Allow file creation via upload" //usage: "\n -u Access files as USER" #include "libbb.h" #if ENABLE_FEATURE_TFTP_GET || ENABLE_FEATURE_TFTP_PUT #define TFTP_BLKSIZE_DEFAULT 512 /* according to RFC 1350, don't change */ #define TFTP_BLKSIZE_DEFAULT_STR "512" /* Was 50 ms but users asked to bump it up a bit */ #define TFTP_TIMEOUT_MS 100 #define TFTP_MAXTIMEOUT_MS 2000 #define TFTP_NUM_RETRIES 12 /* number of backed-off retries */ /* opcodes we support */ #define TFTP_RRQ 1 #define TFTP_WRQ 2 #define TFTP_DATA 3 #define TFTP_ACK 4 #define TFTP_ERROR 5 #define TFTP_OACK 6 /* error codes sent over network (we use only 0, 1, 3 and 8) */ /* generic (error message is included in the packet) */ #define ERR_UNSPEC 0 #define ERR_NOFILE 1 #define ERR_ACCESS 2 /* disk full or allocation exceeded */ #define ERR_WRITE 3 #define ERR_OP 4 #define ERR_BAD_ID 5 #define ERR_EXIST 6 #define ERR_BAD_USER 7 #define ERR_BAD_OPT 8 /* masks coming from getopt32 */ enum { TFTP_OPT_GET = (1 << 0), TFTP_OPT_PUT = (1 << 1), /* pseudo option: if set, it's tftpd */ TFTPD_OPT = (1 << 7) * ENABLE_TFTPD, TFTPD_OPT_r = (1 << 8) * ENABLE_TFTPD, TFTPD_OPT_c = (1 << 9) * ENABLE_TFTPD, TFTPD_OPT_u = (1 << 10) * ENABLE_TFTPD, }; #if ENABLE_FEATURE_TFTP_GET && !ENABLE_FEATURE_TFTP_PUT #define IF_GETPUT(...) #define CMD_GET(cmd) 1 #define CMD_PUT(cmd) 0 #elif !ENABLE_FEATURE_TFTP_GET && ENABLE_FEATURE_TFTP_PUT #define IF_GETPUT(...) #define CMD_GET(cmd) 0 #define CMD_PUT(cmd) 1 #else #define IF_GETPUT(...) __VA_ARGS__ #define CMD_GET(cmd) ((cmd) & TFTP_OPT_GET) #define CMD_PUT(cmd) ((cmd) & TFTP_OPT_PUT) #endif /* NB: in the code below * CMD_GET(cmd) and CMD_PUT(cmd) are mutually exclusive */ struct globals { /* u16 TFTP_ERROR; u16 reason; both network-endian, then error text: */ uint8_t error_pkt[4 + 32]; char *user_opt; /* used in tftpd_main(), a bit big for stack: */ char block_buf[TFTP_BLKSIZE_DEFAULT]; #if ENABLE_FEATURE_TFTP_PROGRESS_BAR off_t pos; off_t size; const char *file; bb_progress_t pmt; #endif } FIX_ALIASING; #define G (*(struct globals*)&bb_common_bufsiz1) struct BUG_G_too_big { char BUG_G_too_big[sizeof(G) <= COMMON_BUFSIZE ? 1 : -1]; }; #define block_buf (G.block_buf ) #define user_opt (G.user_opt ) #define error_pkt (G.error_pkt ) #define INIT_G() do { } while (0) #define error_pkt_reason (error_pkt[3]) #define error_pkt_str (error_pkt + 4) #if ENABLE_FEATURE_TFTP_PROGRESS_BAR static void tftp_progress_update(void) { bb_progress_update(&G.pmt, 0, G.pos, G.size); } static void tftp_progress_init(void) { bb_progress_init(&G.pmt, G.file); tftp_progress_update(); } static void tftp_progress_done(void) { if (is_bb_progress_inited(&G.pmt)) { tftp_progress_update(); bb_putchar_stderr('\n'); bb_progress_free(&G.pmt); } } #else # define tftp_progress_init() ((void)0) # define tftp_progress_done() ((void)0) #endif #if ENABLE_FEATURE_TFTP_BLOCKSIZE static int tftp_blksize_check(const char *blksize_str, int maxsize) { /* Check if the blksize is valid: * RFC2348 says between 8 and 65464, * but our implementation makes it impossible * to use blksizes smaller than 22 octets. */ unsigned blksize = bb_strtou(blksize_str, NULL, 10); if (errno || (blksize < 24) || (blksize > maxsize) ) { bb_error_msg("bad blocksize '%s'", blksize_str); return -1; } # if ENABLE_TFTP_DEBUG bb_error_msg("using blksize %u", blksize); # endif return blksize; } static char *tftp_get_option(const char *option, char *buf, int len) { int opt_val = 0; int opt_found = 0; int k; /* buf points to: * "opt_nameopt_valopt_name2opt_val2..." */ while (len > 0) { /* Make sure options are terminated correctly */ for (k = 0; k < len; k++) { if (buf[k] == '\0') { goto nul_found; } } return NULL; nul_found: if (opt_val == 0) { /* it's "name" part */ if (strcasecmp(buf, option) == 0) { opt_found = 1; } } else if (opt_found) { return buf; } k++; buf += k; len -= k; opt_val ^= 1; } return NULL; } #endif static int tftp_protocol( /* NULL if tftp, !NULL if tftpd: */ len_and_sockaddr *our_lsa, len_and_sockaddr *peer_lsa, const char *local_file IF_TFTP(, const char *remote_file) #if !ENABLE_TFTP # define remote_file NULL #endif /* 1 for tftp; 1/0 for tftpd depending whether client asked about it: */ IF_FEATURE_TFTP_BLOCKSIZE(, int want_transfer_size) IF_FEATURE_TFTP_BLOCKSIZE(, int blksize)) { #if !ENABLE_FEATURE_TFTP_BLOCKSIZE enum { blksize = TFTP_BLKSIZE_DEFAULT }; #endif struct pollfd pfd[1]; #define socket_fd (pfd[0].fd) int len; int send_len; IF_FEATURE_TFTP_BLOCKSIZE(smallint expect_OACK = 0;) smallint finished = 0; uint16_t opcode; uint16_t block_nr; uint16_t recv_blk; int open_mode, local_fd; int retries, waittime_ms; int io_bufsize = blksize + 4; char *cp; /* Can't use RESERVE_CONFIG_BUFFER here since the allocation * size varies meaning BUFFERS_GO_ON_STACK would fail. * * We must keep the transmit and receive buffers separate * in case we rcv a garbage pkt - we need to rexmit the last pkt. */ char *xbuf = xmalloc(io_bufsize); char *rbuf = xmalloc(io_bufsize); socket_fd = xsocket(peer_lsa->u.sa.sa_family, SOCK_DGRAM, 0); setsockopt_reuseaddr(socket_fd); if (!ENABLE_TFTP || our_lsa) { /* tftpd */ /* Create a socket which is: * 1. bound to IP:port peer sent 1st datagram to, * 2. connected to peer's IP:port * This way we will answer from the IP:port peer * expects, will not get any other packets on * the socket, and also plain read/write will work. */ xbind(socket_fd, &our_lsa->u.sa, our_lsa->len); xconnect(socket_fd, &peer_lsa->u.sa, peer_lsa->len); /* Is there an error already? Send pkt and bail out */ if (error_pkt_reason || error_pkt_str[0]) goto send_err_pkt; if (user_opt) { struct passwd *pw = xgetpwnam(user_opt); change_identity(pw); /* initgroups, setgid, setuid */ } } /* Prepare open mode */ if (CMD_PUT(option_mask32)) { open_mode = O_RDONLY; } else { open_mode = O_WRONLY | O_TRUNC | O_CREAT; #if ENABLE_TFTPD if ((option_mask32 & (TFTPD_OPT+TFTPD_OPT_c)) == TFTPD_OPT) { /* tftpd without -c */ open_mode = O_WRONLY | O_TRUNC; } #endif } /* Examples of network traffic. * Note two cases when ACKs with block# of 0 are sent. * * Download without options: * tftp -> "\0\1FILENAME\0octet\0" * "\0\3\0\1FILEDATA..." <- tftpd * tftp -> "\0\4\0\1" * ... * Download with option of blksize 16384: * tftp -> "\0\1FILENAME\0octet\0blksize\00016384\0" * "\0\6blksize\00016384\0" <- tftpd * tftp -> "\0\4\0\0" * "\0\3\0\1FILEDATA..." <- tftpd * tftp -> "\0\4\0\1" * ... * Upload without options: * tftp -> "\0\2FILENAME\0octet\0" * "\0\4\0\0" <- tftpd * tftp -> "\0\3\0\1FILEDATA..." * "\0\4\0\1" <- tftpd * ... * Upload with option of blksize 16384: * tftp -> "\0\2FILENAME\0octet\0blksize\00016384\0" * "\0\6blksize\00016384\0" <- tftpd * tftp -> "\0\3\0\1FILEDATA..." * "\0\4\0\1" <- tftpd * ... */ block_nr = 1; cp = xbuf + 2; if (!ENABLE_TFTP || our_lsa) { /* tftpd */ /* Open file (must be after changing user) */ local_fd = open(local_file, open_mode, 0666); if (local_fd < 0) { error_pkt_reason = ERR_NOFILE; strcpy((char*)error_pkt_str, "can't open file"); goto send_err_pkt; } /* gcc 4.3.1 would NOT optimize it out as it should! */ #if ENABLE_FEATURE_TFTP_BLOCKSIZE if (blksize != TFTP_BLKSIZE_DEFAULT || want_transfer_size) { /* Create and send OACK packet. */ /* For the download case, block_nr is still 1 - * we expect 1st ACK from peer to be for (block_nr-1), * that is, for "block 0" which is our OACK pkt */ opcode = TFTP_OACK; goto add_blksize_opt; } #endif if (CMD_GET(option_mask32)) { /* It's upload and we don't send OACK. * We must ACK 1st packet (with filename) * as if it is "block 0" */ block_nr = 0; } } else { /* tftp */ /* Open file (must be after changing user) */ local_fd = CMD_GET(option_mask32) ? STDOUT_FILENO : STDIN_FILENO; if (NOT_LONE_DASH(local_file)) local_fd = xopen(local_file, open_mode); /* Removing #if, or using if() statement instead of #if may lead to * "warning: null argument where non-null required": */ #if ENABLE_TFTP /* tftp */ /* We can't (and don't really need to) bind the socket: * we don't know from which local IP datagrams will be sent, * but kernel will pick the same IP every time (unless routing * table is changed), thus peer will see dgrams consistently * coming from the same IP. * We would like to connect the socket, but since peer's * UDP code can be less perfect than ours, _peer's_ IP:port * in replies may differ from IP:port we used to send * our first packet. We can connect() only when we get * first reply. */ /* build opcode */ opcode = TFTP_WRQ; if (CMD_GET(option_mask32)) { opcode = TFTP_RRQ; } /* add filename and mode */ /* fill in packet if the filename fits into xbuf */ len = strlen(remote_file) + 1; if (2 + len + sizeof("octet") >= io_bufsize) { bb_error_msg("remote filename is too long"); goto ret; } strcpy(cp, remote_file); cp += len; /* add "mode" part of the packet */ strcpy(cp, "octet"); cp += sizeof("octet"); # if ENABLE_FEATURE_TFTP_BLOCKSIZE if (blksize == TFTP_BLKSIZE_DEFAULT && !want_transfer_size) goto send_pkt; /* Need to add option to pkt */ if ((&xbuf[io_bufsize - 1] - cp) < sizeof("blksize NNNNN tsize ") + sizeof(off_t)*3) { bb_error_msg("remote filename is too long"); goto ret; } expect_OACK = 1; # endif #endif /* ENABLE_TFTP */ #if ENABLE_FEATURE_TFTP_BLOCKSIZE add_blksize_opt: if (blksize != TFTP_BLKSIZE_DEFAULT) { /* add "blksize", , blksize, */ strcpy(cp, "blksize"); cp += sizeof("blksize"); cp += snprintf(cp, 6, "%d", blksize) + 1; } if (want_transfer_size) { /* add "tsize", , size, (see RFC2349) */ /* if tftp and downloading, we send "0" (since we opened local_fd with O_TRUNC) * and this makes server to send "tsize" option with the size */ /* if tftp and uploading, we send file size (maybe dont, to not confuse old servers???) */ /* if tftpd and downloading, we are answering to client's request */ /* if tftpd and uploading: !want_transfer_size, this code is not executed */ struct stat st; strcpy(cp, "tsize"); cp += sizeof("tsize"); st.st_size = 0; fstat(local_fd, &st); cp += sprintf(cp, "%"OFF_FMT"u", (off_t)st.st_size) + 1; # if ENABLE_FEATURE_TFTP_PROGRESS_BAR /* Save for progress bar. If 0 (tftp downloading), * we look at server's reply later */ G.size = st.st_size; if (remote_file && st.st_size) tftp_progress_init(); # endif } #endif /* First packet is built, so skip packet generation */ goto send_pkt; } /* Using mostly goto's - continue/break will be less clear * in where we actually jump to */ while (1) { /* Build ACK or DATA */ cp = xbuf + 2; *((uint16_t*)cp) = htons(block_nr); cp += 2; block_nr++; opcode = TFTP_ACK; if (CMD_PUT(option_mask32)) { opcode = TFTP_DATA; len = full_read(local_fd, cp, blksize); if (len < 0) { goto send_read_err_pkt; } if (len != blksize) { finished = 1; } cp += len; } send_pkt: /* Send packet */ *((uint16_t*)xbuf) = htons(opcode); /* fill in opcode part */ send_len = cp - xbuf; /* NB: send_len value is preserved in code below * for potential resend */ retries = TFTP_NUM_RETRIES; /* re-initialize */ waittime_ms = TFTP_TIMEOUT_MS; send_again: #if ENABLE_TFTP_DEBUG fprintf(stderr, "sending %u bytes\n", send_len); for (cp = xbuf; cp < &xbuf[send_len]; cp++) fprintf(stderr, "%02x ", (unsigned char) *cp); fprintf(stderr, "\n"); #endif xsendto(socket_fd, xbuf, send_len, &peer_lsa->u.sa, peer_lsa->len); #if ENABLE_FEATURE_TFTP_PROGRESS_BAR if (ENABLE_TFTP && remote_file) /* tftp */ G.pos = (block_nr - 1) * (uoff_t)blksize; if (is_bb_progress_inited(&G.pmt)) tftp_progress_update(); #endif /* Was it final ACK? then exit */ if (finished && (opcode == TFTP_ACK)) goto ret; recv_again: /* Receive packet */ /*pfd[0].fd = socket_fd;*/ pfd[0].events = POLLIN; switch (safe_poll(pfd, 1, waittime_ms)) { default: /*bb_perror_msg("poll"); - done in safe_poll */ goto ret; case 0: retries--; if (retries == 0) { tftp_progress_done(); bb_error_msg("timeout"); goto ret; /* no err packet sent */ } /* exponential backoff with limit */ waittime_ms += waittime_ms/2; if (waittime_ms > TFTP_MAXTIMEOUT_MS) { waittime_ms = TFTP_MAXTIMEOUT_MS; } goto send_again; /* resend last sent pkt */ case 1: if (!our_lsa) { /* tftp (not tftpd!) receiving 1st packet */ our_lsa = ((void*)(ptrdiff_t)-1); /* not NULL */ len = recvfrom(socket_fd, rbuf, io_bufsize, 0, &peer_lsa->u.sa, &peer_lsa->len); /* Our first dgram went to port 69 * but reply may come from different one. * Remember and use this new port (and IP) */ if (len >= 0) xconnect(socket_fd, &peer_lsa->u.sa, peer_lsa->len); } else { /* tftpd, or not the very first packet: * socket is connect()ed, can just read from it. */ /* Don't full_read()! * This is not TCP, one read == one pkt! */ len = safe_read(socket_fd, rbuf, io_bufsize); } if (len < 0) { goto send_read_err_pkt; } if (len < 4) { /* too small? */ goto recv_again; } } /* Process recv'ed packet */ opcode = ntohs( ((uint16_t*)rbuf)[0] ); recv_blk = ntohs( ((uint16_t*)rbuf)[1] ); #if ENABLE_TFTP_DEBUG fprintf(stderr, "received %d bytes: %04x %04x\n", len, opcode, recv_blk); #endif if (opcode == TFTP_ERROR) { static const char errcode_str[] ALIGN1 = "\0" "file not found\0" "access violation\0" "disk full\0" "bad operation\0" "unknown transfer id\0" "file already exists\0" "no such user\0" "bad option"; const char *msg = ""; if (len > 4 && rbuf[4] != '\0') { msg = &rbuf[4]; rbuf[io_bufsize - 1] = '\0'; /* paranoia */ } else if (recv_blk <= 8) { msg = nth_string(errcode_str, recv_blk); } bb_error_msg("server error: (%u) %s", recv_blk, msg); goto ret; } #if ENABLE_FEATURE_TFTP_BLOCKSIZE if (expect_OACK) { expect_OACK = 0; if (opcode == TFTP_OACK) { /* server seems to support options */ char *res; res = tftp_get_option("blksize", &rbuf[2], len - 2); if (res) { blksize = tftp_blksize_check(res, blksize); if (blksize < 0) { error_pkt_reason = ERR_BAD_OPT; goto send_err_pkt; } io_bufsize = blksize + 4; } # if ENABLE_FEATURE_TFTP_PROGRESS_BAR if (remote_file && G.size == 0) { /* if we don't know it yet */ res = tftp_get_option("tsize", &rbuf[2], len - 2); if (res) { G.size = bb_strtoull(res, NULL, 10); if (G.size) tftp_progress_init(); } } # endif if (CMD_GET(option_mask32)) { /* We'll send ACK for OACK, * such ACK has "block no" of 0 */ block_nr = 0; } continue; } /* rfc2347: * "An option not acknowledged by the server * must be ignored by the client and server * as if it were never requested." */ if (blksize != TFTP_BLKSIZE_DEFAULT) bb_error_msg("falling back to blocksize "TFTP_BLKSIZE_DEFAULT_STR); blksize = TFTP_BLKSIZE_DEFAULT; io_bufsize = TFTP_BLKSIZE_DEFAULT + 4; } #endif /* block_nr is already advanced to next block# we expect * to get / block# we are about to send next time */ if (CMD_GET(option_mask32) && (opcode == TFTP_DATA)) { if (recv_blk == block_nr) { int sz = full_write(local_fd, &rbuf[4], len - 4); if (sz != len - 4) { strcpy((char*)error_pkt_str, bb_msg_write_error); error_pkt_reason = ERR_WRITE; goto send_err_pkt; } if (sz != blksize) { finished = 1; } continue; /* send ACK */ } /* Disabled to cope with servers with Sorcerer's Apprentice Syndrome */ #if 0 if (recv_blk == (block_nr - 1)) { /* Server lost our TFTP_ACK. Resend it */ block_nr = recv_blk; continue; } #endif } if (CMD_PUT(option_mask32) && (opcode == TFTP_ACK)) { /* did peer ACK our last DATA pkt? */ if (recv_blk == (uint16_t) (block_nr - 1)) { if (finished) goto ret; continue; /* send next block */ } } /* Awww... recv'd packet is not recognized! */ goto recv_again; /* why recv_again? - rfc1123 says: * "The sender (i.e., the side originating the DATA packets) * must never resend the current DATA packet on receipt * of a duplicate ACK". * DATA pkts are resent ONLY on timeout. * Thus "goto send_again" will ba a bad mistake above. * See: * http://en.wikipedia.org/wiki/Sorcerer's_Apprentice_Syndrome */ } /* end of "while (1)" */ ret: if (ENABLE_FEATURE_CLEAN_UP) { close(local_fd); close(socket_fd); free(xbuf); free(rbuf); } return finished == 0; /* returns 1 on failure */ send_read_err_pkt: strcpy((char*)error_pkt_str, bb_msg_read_error); send_err_pkt: if (error_pkt_str[0]) bb_error_msg("%s", (char*)error_pkt_str); error_pkt[1] = TFTP_ERROR; xsendto(socket_fd, error_pkt, 4 + 1 + strlen((char*)error_pkt_str), &peer_lsa->u.sa, peer_lsa->len); return EXIT_FAILURE; #undef remote_file } #if ENABLE_TFTP int tftp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int tftp_main(int argc UNUSED_PARAM, char **argv) { len_and_sockaddr *peer_lsa; const char *local_file = NULL; const char *remote_file = NULL; # if ENABLE_FEATURE_TFTP_BLOCKSIZE const char *blksize_str = TFTP_BLKSIZE_DEFAULT_STR; int blksize; # endif int result; int port; IF_GETPUT(int opt;) INIT_G(); /* -p or -g is mandatory, and they are mutually exclusive */ opt_complementary = "" IF_FEATURE_TFTP_GET("g:") IF_FEATURE_TFTP_PUT("p:") IF_GETPUT("g--p:p--g:"); IF_GETPUT(opt =) getopt32(argv, IF_FEATURE_TFTP_GET("g") IF_FEATURE_TFTP_PUT("p") "l:r:" IF_FEATURE_TFTP_BLOCKSIZE("b:"), &local_file, &remote_file IF_FEATURE_TFTP_BLOCKSIZE(, &blksize_str)); argv += optind; # if ENABLE_FEATURE_TFTP_BLOCKSIZE /* Check if the blksize is valid: * RFC2348 says between 8 and 65464 */ blksize = tftp_blksize_check(blksize_str, 65564); if (blksize < 0) { //bb_error_msg("bad block size"); return EXIT_FAILURE; } # endif if (remote_file) { if (!local_file) { const char *slash = strrchr(remote_file, '/'); local_file = slash ? slash + 1 : remote_file; } } else { remote_file = local_file; } /* Error if filename or host is not known */ if (!remote_file || !argv[0]) bb_show_usage(); port = bb_lookup_port(argv[1], "udp", 69); peer_lsa = xhost2sockaddr(argv[0], port); # if ENABLE_TFTP_DEBUG fprintf(stderr, "using server '%s', remote_file '%s', local_file '%s'\n", xmalloc_sockaddr2dotted(&peer_lsa->u.sa), remote_file, local_file); # endif # if ENABLE_FEATURE_TFTP_PROGRESS_BAR G.file = remote_file; # endif result = tftp_protocol( NULL /*our_lsa*/, peer_lsa, local_file, remote_file IF_FEATURE_TFTP_BLOCKSIZE(, 1 /* want_transfer_size */) IF_FEATURE_TFTP_BLOCKSIZE(, blksize) ); tftp_progress_done(); if (result != EXIT_SUCCESS && NOT_LONE_DASH(local_file) && CMD_GET(opt)) { unlink(local_file); } return result; } #endif /* ENABLE_TFTP */ #if ENABLE_TFTPD int tftpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int tftpd_main(int argc UNUSED_PARAM, char **argv) { len_and_sockaddr *our_lsa; len_and_sockaddr *peer_lsa; char *local_file, *mode; const char *error_msg; int opt, result, opcode; IF_FEATURE_TFTP_BLOCKSIZE(int blksize = TFTP_BLKSIZE_DEFAULT;) IF_FEATURE_TFTP_BLOCKSIZE(int want_transfer_size = 0;) INIT_G(); our_lsa = get_sock_lsa(STDIN_FILENO); if (!our_lsa) { /* This is confusing: *bb_error_msg_and_die("stdin is not a socket"); * Better: */ bb_show_usage(); /* Help text says that tftpd must be used as inetd service, * which is by far the most usual cause of get_sock_lsa * failure */ } peer_lsa = xzalloc(LSA_LEN_SIZE + our_lsa->len); peer_lsa->len = our_lsa->len; /* Shifting to not collide with TFTP_OPTs */ opt = option_mask32 = TFTPD_OPT | (getopt32(argv, "rcu:", &user_opt) << 8); argv += optind; if (argv[0]) xchdir(argv[0]); result = recv_from_to(STDIN_FILENO, block_buf, sizeof(block_buf), 0 /* flags */, &peer_lsa->u.sa, &our_lsa->u.sa, our_lsa->len); error_msg = "malformed packet"; opcode = ntohs(*(uint16_t*)block_buf); if (result < 4 || result >= sizeof(block_buf) || block_buf[result-1] != '\0' || (IF_FEATURE_TFTP_PUT(opcode != TFTP_RRQ) /* not download */ IF_GETPUT(&&) IF_FEATURE_TFTP_GET(opcode != TFTP_WRQ) /* not upload */ ) ) { goto err; } local_file = block_buf + 2; if (local_file[0] == '.' || strstr(local_file, "/.")) { error_msg = "dot in file name"; goto err; } mode = local_file + strlen(local_file) + 1; if (mode >= block_buf + result || strcmp(mode, "octet") != 0) { goto err; } # if ENABLE_FEATURE_TFTP_BLOCKSIZE { char *res; char *opt_str = mode + sizeof("octet"); int opt_len = block_buf + result - opt_str; if (opt_len > 0) { res = tftp_get_option("blksize", opt_str, opt_len); if (res) { blksize = tftp_blksize_check(res, 65564); if (blksize < 0) { error_pkt_reason = ERR_BAD_OPT; /* will just send error pkt */ goto do_proto; } } if (opcode != TFTP_WRQ /* download? */ /* did client ask us about file size? */ && tftp_get_option("tsize", opt_str, opt_len) ) { want_transfer_size = 1; } } } # endif if (!ENABLE_FEATURE_TFTP_PUT || opcode == TFTP_WRQ) { if (opt & TFTPD_OPT_r) { /* This would mean "disk full" - not true */ /*error_pkt_reason = ERR_WRITE;*/ error_msg = bb_msg_write_error; goto err; } IF_GETPUT(option_mask32 |= TFTP_OPT_GET;) /* will receive file's data */ } else { IF_GETPUT(option_mask32 |= TFTP_OPT_PUT;) /* will send file's data */ } /* NB: if error_pkt_str or error_pkt_reason is set up, * tftp_protocol() just sends one error pkt and returns */ do_proto: close(STDIN_FILENO); /* close old, possibly wildcard socket */ /* tftp_protocol() will create new one, bound to particular local IP */ result = tftp_protocol( our_lsa, peer_lsa, local_file IF_TFTP(, NULL /*remote_file*/) IF_FEATURE_TFTP_BLOCKSIZE(, want_transfer_size) IF_FEATURE_TFTP_BLOCKSIZE(, blksize) ); return result; err: strcpy((char*)error_pkt_str, error_msg); goto do_proto; } #endif /* ENABLE_TFTPD */ #endif /* ENABLE_FEATURE_TFTP_GET || ENABLE_FEATURE_TFTP_PUT */