| /* vi: set sw=4 ts=4: */ |
| /* ------------------------------------------------------------------------- |
| * tftp.c |
| * |
| * A simple tftp client for busybox. |
| * Tries to follow RFC1350. |
| * Only "octet" mode supported. |
| * Optional blocksize negotiation (RFC2347 + RFC2348) |
| * |
| * Copyright (C) 2001 Magnus Damm <damm@opensource.se> |
| * |
| * Parts of the code based on: |
| * |
| * atftp: Copyright (C) 2000 Jean-Pierre Lefebvre <helix@step.polymtl.ca> |
| * and Remi Lefebvre <remi@debian.org> |
| * |
| * utftp: Copyright (C) 1999 Uwe Ohse <uwe@ohse.de> |
| * |
| * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
| * ------------------------------------------------------------------------- */ |
| |
| #include "libbb.h" |
| |
| #if ENABLE_FEATURE_TFTP_GET || ENABLE_FEATURE_TFTP_PUT |
| |
| #define TFTP_BLOCKSIZE_DEFAULT 512 /* according to RFC 1350, don't change */ |
| #define TFTP_TIMEOUT_MS 50 |
| #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 |
| |
| #if ENABLE_FEATURE_TFTP_GET && !ENABLE_FEATURE_TFTP_PUT |
| #define USE_GETPUT(...) |
| #define CMD_GET(cmd) 1 |
| #define CMD_PUT(cmd) 0 |
| #elif !ENABLE_FEATURE_TFTP_GET && ENABLE_FEATURE_TFTP_PUT |
| #define USE_GETPUT(...) |
| #define CMD_GET(cmd) 0 |
| #define CMD_PUT(cmd) 1 |
| #else |
| #define USE_GETPUT(...) __VA_ARGS__ |
| /* masks coming from getpot32 */ |
| #define CMD_GET(cmd) ((cmd) & 1) |
| #define CMD_PUT(cmd) ((cmd) & 2) |
| #endif |
| /* NB: in the code below |
| * CMD_GET(cmd) and CMD_PUT(cmd) are mutually exclusive |
| */ |
| |
| |
| #if ENABLE_FEATURE_TFTP_BLOCKSIZE |
| |
| static int tftp_blocksize_check(int blocksize, int bufsize) |
| { |
| /* Check if the blocksize is valid: |
| * RFC2348 says between 8 and 65464, |
| * but our implementation makes it impossible |
| * to use blocksizes smaller than 22 octets. |
| */ |
| |
| if ((bufsize && (blocksize > bufsize)) |
| || (blocksize < 8) || (blocksize > 65564) |
| ) { |
| bb_error_msg("bad blocksize"); |
| return 0; |
| } |
| |
| return blocksize; |
| } |
| |
| static char *tftp_option_get(char *buf, int len, const char *option) |
| { |
| int opt_val = 0; |
| int opt_found = 0; |
| int k; |
| |
| while (len > 0) { |
| /* Make sure the 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) { |
| 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( USE_GETPUT(const int cmd,) |
| len_and_sockaddr *peer_lsa, |
| const char *remotefile, const int localfd, |
| unsigned port, int tftp_bufsize) |
| { |
| struct pollfd pfd[1]; |
| #define socketfd (pfd[0].fd) |
| int len; |
| int send_len; |
| USE_FEATURE_TFTP_BLOCKSIZE(smallint want_option_ack = 0;) |
| smallint finished = 0; |
| uint16_t opcode; |
| uint16_t block_nr = 1; |
| uint16_t recv_blk; |
| int retries, waittime_ms; |
| char *cp; |
| |
| unsigned org_port; |
| len_and_sockaddr *const from = alloca(offsetof(len_and_sockaddr, sa) + peer_lsa->len); |
| |
| /* 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 seperate */ |
| /* In case we rcv a garbage pkt and we need to rexmit the last pkt */ |
| char *xbuf = xmalloc(tftp_bufsize += 4); |
| char *rbuf = xmalloc(tftp_bufsize); |
| |
| port = org_port = htons(port); |
| |
| socketfd = xsocket(peer_lsa->sa.sa_family, SOCK_DGRAM, 0); |
| |
| /* build opcode */ |
| opcode = TFTP_WRQ; |
| if (CMD_GET(cmd)) { |
| opcode = TFTP_RRQ; |
| } |
| cp = xbuf + 2; |
| /* add filename and mode */ |
| /* fill in packet if the filename fits into xbuf */ |
| len = strlen(remotefile) + 1; |
| if (2 + len + sizeof("octet") >= tftp_bufsize) { |
| bb_error_msg("remote filename is too long"); |
| goto ret; |
| } |
| strcpy(cp, remotefile); |
| cp += len; |
| /* add "mode" part of the package */ |
| strcpy(cp, "octet"); |
| cp += sizeof("octet"); |
| |
| #if ENABLE_FEATURE_TFTP_BLOCKSIZE |
| len = tftp_bufsize - 4; /* data block size */ |
| if (len != TFTP_BLOCKSIZE_DEFAULT) { |
| /* rfc2348 says that 65464 is a max allowed value */ |
| if ((&xbuf[tftp_bufsize - 1] - cp) < sizeof("blksize NNNNN")) { |
| bb_error_msg("remote filename is too long"); |
| goto ret; |
| } |
| /* add "blksize", <nul>, blocksize */ |
| strcpy(cp, "blksize"); |
| cp += sizeof("blksize"); |
| cp += snprintf(cp, 6, "%d", len) + 1; |
| want_option_ack = 1; |
| } |
| #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(cmd)) { |
| opcode = TFTP_DATA; |
| len = full_read(localfd, cp, tftp_bufsize - 4); |
| if (len < 0) { |
| bb_perror_msg(bb_msg_read_error); |
| goto ret; |
| } |
| if (len != (tftp_bufsize - 4)) { |
| 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_DEBUG_TFTP |
| 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(socketfd, xbuf, send_len, &peer_lsa->sa, peer_lsa->len); |
| /* Was it final ACK? then exit */ |
| if (finished && (opcode == TFTP_ACK)) |
| goto ret; |
| |
| recv_again: |
| /* Receive packet */ |
| /*pfd[0].fd = socketfd;*/ |
| pfd[0].events = POLLIN; |
| switch (safe_poll(pfd, 1, waittime_ms)) { |
| unsigned from_port; |
| case 1: |
| from->len = peer_lsa->len; |
| memset(&from->sa, 0, peer_lsa->len); |
| len = recvfrom(socketfd, rbuf, tftp_bufsize, 0, |
| &from->sa, &from->len); |
| if (len < 0) { |
| bb_perror_msg("recvfrom"); |
| goto ret; |
| } |
| from_port = get_nport(&from->sa); |
| if (port == org_port) { |
| /* Our first query went to port 69 |
| * but reply will come from different one. |
| * Remember and use this new port */ |
| port = from_port; |
| set_nport(peer_lsa, from_port); |
| } |
| if (port != from_port) |
| goto recv_again; |
| goto process_pkt; |
| case 0: |
| retries--; |
| if (retries == 0) { |
| bb_error_msg("timeout"); |
| goto ret; |
| } |
| |
| /* 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 */ |
| default: |
| /*bb_perror_msg("poll"); - done in safe_poll */ |
| goto ret; |
| } |
| process_pkt: |
| /* Process recv'ed packet */ |
| opcode = ntohs( ((uint16_t*)rbuf)[0] ); |
| recv_blk = ntohs( ((uint16_t*)rbuf)[1] ); |
| |
| #if ENABLE_DEBUG_TFTP |
| fprintf(stderr, "received %d bytes: %04x %04x\n", len, opcode, recv_blk); |
| #endif |
| |
| if (opcode == TFTP_ERROR) { |
| static const char *const errcode_str[] = { |
| "", |
| "file not found", |
| "access violation", |
| "disk full", |
| "illegal TFTP operation", |
| "unknown transfer id", |
| "file already exists", |
| "no such user", |
| "bad option" |
| }; |
| |
| const char *msg = ""; |
| |
| if (rbuf[4] != '\0') { |
| msg = &rbuf[4]; |
| rbuf[tftp_bufsize - 1] = '\0'; |
| } else if (recv_blk < ARRAY_SIZE(errcode_str)) { |
| msg = errcode_str[recv_blk]; |
| } |
| bb_error_msg("server error: (%u) %s", recv_blk, msg); |
| goto ret; |
| } |
| |
| #if ENABLE_FEATURE_TFTP_BLOCKSIZE |
| if (want_option_ack) { |
| want_option_ack = 0; |
| |
| if (opcode == TFTP_OACK) { |
| /* server seems to support options */ |
| char *res; |
| |
| res = tftp_option_get(&rbuf[2], len - 2, "blksize"); |
| if (res) { |
| int blksize = xatoi_u(res); |
| if (!tftp_blocksize_check(blksize, tftp_bufsize - 4)) { |
| /* send ERROR 8 to server... */ |
| /* htons can be impossible to use in const initializer: */ |
| /*static const uint16_t error_8[2] = { htons(TFTP_ERROR), htons(8) };*/ |
| /* thus we open-code big-endian layout */ |
| static const uint8_t error_8[4] = { 0,TFTP_ERROR, 0,8 }; |
| xsendto(socketfd, error_8, 4, &peer_lsa->sa, peer_lsa->len); |
| bb_error_msg("server proposes bad blksize %d, exiting", blksize); |
| goto ret; |
| } |
| #if ENABLE_DEBUG_TFTP |
| fprintf(stderr, "using blksize %u\n", |
| blksize); |
| #endif |
| tftp_bufsize = blksize + 4; |
| /* Send ACK for OACK ("block" no: 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." */ |
| } |
| |
| bb_error_msg("blksize is not supported by server" |
| " - reverting to 512"); |
| tftp_bufsize = TFTP_BLOCKSIZE_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(cmd) && (opcode == TFTP_DATA)) { |
| if (recv_blk == block_nr) { |
| len = full_write(localfd, &rbuf[4], len - 4); |
| if (len < 0) { |
| bb_perror_msg(bb_msg_write_error); |
| goto ret; |
| } |
| if (len != (tftp_bufsize - 4)) { |
| finished = 1; |
| } |
| continue; /* send ACK */ |
| } |
| if (recv_blk == (block_nr - 1)) { |
| /* Server lost our TFTP_ACK. Resend it */ |
| block_nr = recv_blk; |
| continue; |
| } |
| } |
| |
| if (CMD_PUT(cmd) && (opcode == TFTP_ACK)) { |
| /* did server 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 |
| */ |
| } |
| ret: |
| if (ENABLE_FEATURE_CLEAN_UP) { |
| close(socketfd); |
| free(xbuf); |
| free(rbuf); |
| } |
| return finished == 0; /* returns 1 on failure */ |
| } |
| |
| int tftp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int tftp_main(int argc, char **argv) |
| { |
| len_and_sockaddr *peer_lsa; |
| const char *localfile = NULL; |
| const char *remotefile = NULL; |
| #if ENABLE_FEATURE_TFTP_BLOCKSIZE |
| const char *sblocksize = NULL; |
| #endif |
| int port; |
| USE_GETPUT(int cmd;) |
| int fd = -1; |
| int flags = 0; |
| int result; |
| int blocksize = TFTP_BLOCKSIZE_DEFAULT; |
| |
| /* -p or -g is mandatory, and they are mutually exclusive */ |
| opt_complementary = "" USE_FEATURE_TFTP_GET("g:") USE_FEATURE_TFTP_PUT("p:") |
| USE_GETPUT("?g--p:p--g"); |
| |
| USE_GETPUT(cmd =) getopt32(argv, |
| USE_FEATURE_TFTP_GET("g") USE_FEATURE_TFTP_PUT("p") |
| "l:r:" USE_FEATURE_TFTP_BLOCKSIZE("b:"), |
| &localfile, &remotefile |
| USE_FEATURE_TFTP_BLOCKSIZE(, &sblocksize)); |
| argv += optind; |
| |
| flags = O_RDONLY; |
| if (CMD_GET(cmd)) |
| flags = O_WRONLY | O_CREAT | O_TRUNC; |
| |
| #if ENABLE_FEATURE_TFTP_BLOCKSIZE |
| if (sblocksize) { |
| blocksize = xatoi_u(sblocksize); |
| if (!tftp_blocksize_check(blocksize, 0)) { |
| return EXIT_FAILURE; |
| } |
| } |
| #endif |
| |
| if (!localfile) |
| localfile = remotefile; |
| if (!remotefile) |
| remotefile = localfile; |
| /* Error if filename or host is not known */ |
| if (!remotefile || !argv[0]) |
| bb_show_usage(); |
| |
| fd = CMD_GET(cmd) ? STDOUT_FILENO : STDIN_FILENO; |
| if (!LONE_DASH(localfile)) { |
| fd = xopen(localfile, flags); |
| } |
| |
| port = bb_lookup_port(argv[1], "udp", 69); |
| peer_lsa = xhost2sockaddr(argv[0], port); |
| |
| #if ENABLE_DEBUG_TFTP |
| fprintf(stderr, "using server '%s', remotefile '%s', localfile '%s'\n", |
| xmalloc_sockaddr2dotted(&peer_lsa->sa), |
| remotefile, localfile); |
| #endif |
| |
| result = tftp( USE_GETPUT(cmd,) peer_lsa, remotefile, fd, port, blocksize); |
| |
| if (ENABLE_FEATURE_CLEAN_UP) |
| close(fd); |
| if (result != EXIT_SUCCESS && !LONE_DASH(localfile) && CMD_GET(cmd)) { |
| unlink(localfile); |
| } |
| return result; |
| } |
| |
| #endif /* ENABLE_FEATURE_TFTP_GET || ENABLE_FEATURE_TFTP_PUT */ |