diff options
| -rw-r--r-- | networking/tftp.c | 368 |
1 files changed, 159 insertions, 209 deletions
diff --git a/networking/tftp.c b/networking/tftp.c index 0621dde69..1f1dfff71 100644 --- a/networking/tftp.c +++ b/networking/tftp.c @@ -36,17 +36,6 @@ #define TFTP_ERROR 5 #define TFTP_OACK 6 -static const char *const tftp_bb_error_msg[] = { - "Undefined error", - "File not found", - "Access violation", - "Disk full or allocation error", - "Illegal TFTP operation", - "Unknown transfer ID", - "File already exists", - "No such user" -}; - #if ENABLE_FEATURE_TFTP_GET && !ENABLE_FEATURE_TFTP_PUT #define USE_GETPUT(a) #define CMD_GET(cmd) 1 @@ -62,7 +51,7 @@ static const char *const tftp_bb_error_msg[] = { #define CMD_PUT(cmd) ((cmd) & 2) #endif /* NB: in the code below - * CMD_GET(cmd) and CMD_GET(cmd) are mutually exclusive + * CMD_GET(cmd) and CMD_PUT(cmd) are mutually exclusive */ @@ -86,7 +75,7 @@ static int tftp_blocksize_check(int blocksize, int bufsize) return blocksize; } -static char *tftp_option_get(char *buf, int len, const char * const option) +static char *tftp_option_get(char *buf, int len, const char *option) { int opt_val = 0; int opt_found = 0; @@ -94,32 +83,24 @@ static char *tftp_option_get(char *buf, int len, const char * const option) while (len > 0) { /* Make sure the options are terminated correctly */ - for (k = 0; k < len; k++) { if (buf[k] == '\0') { - break; + goto nul_found; } } - - if (k >= len) { - break; - } - + return NULL; + nul_found: if (opt_val == 0) { if (strcasecmp(buf, option) == 0) { opt_found = 1; } - } else { - if (opt_found) { - return buf; - } + } else if (opt_found) { + return buf; } k++; - buf += k; len -= k; - opt_val ^= 1; } @@ -140,15 +121,15 @@ static int tftp( fd_set rfds; int socketfd; int len; - int opcode = 0; - int finished = 0; - int timeout = TFTP_NUM_RETRIES; + 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 tmp; + uint16_t recv_blk; + int timeout = TFTP_NUM_RETRIES; char *cp; - USE_FEATURE_TFTP_BLOCKSIZE(int want_option_ack = 0;) - unsigned org_port; len_and_sockaddr *const from = alloca(offsetof(len_and_sockaddr, sa) + peer_lsa->len); @@ -168,109 +149,83 @@ static int tftp( if (CMD_GET(cmd)) { opcode = TFTP_RRQ; } - - while (1) { - cp = xbuf; - - /* first create the opcode part */ - /* (this 16bit store is aligned) */ - *((uint16_t*)cp) = htons(opcode); - cp += 2; - - /* add filename and mode */ - if (CMD_GET(cmd) ? (opcode == TFTP_RRQ) : (opcode == TFTP_WRQ)) { - int too_long = 0; - - /* see if the filename fits into xbuf - * and fill in packet. */ - len = strlen(remotefile) + 1; - - if ((cp + len) >= &xbuf[tftp_bufsize - 1]) { - too_long = 1; - } else { - safe_strncpy(cp, remotefile, len); - cp += len; - } - - if (too_long || (&xbuf[tftp_bufsize - 1] - cp) < sizeof("octet")) { - bb_error_msg("remote filename too long"); - break; - } - - /* add "mode" part of the package */ - memcpy(cp, "octet", sizeof("octet")); - cp += sizeof("octet"); + 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) { - - if ((&xbuf[tftp_bufsize - 1] - cp) < 15) { - bb_error_msg("remote filename too long"); - break; - } - - /* add "blksize" + number of blocks */ - memcpy(cp, "blksize", sizeof("blksize")); - cp += sizeof("blksize"); - cp += snprintf(cp, 6, "%d", len) + 1; - - want_option_ack = 1; - } -#endif + 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; - /* add ack and data */ - - if (CMD_GET(cmd) ? (opcode == TFTP_ACK) : (opcode == TFTP_DATA)) { - /* TODO: unaligned access! */ - *((uint16_t*)cp) = htons(block_nr); - cp += 2; - block_nr++; - - 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); - break; - } - - if (len != (tftp_bufsize - 4)) { - finished++; - } - - cp += len; + 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 packet */ - + send_pkt: + /* Send packet */ + *((uint16_t*)xbuf) = htons(opcode); /* fill in opcode part */ timeout = TFTP_NUM_RETRIES; /* re-initialize */ - do { - len = cp - xbuf; + while (1) { + send_len = cp - xbuf; + /* nb: need to preserve send_len value in code below + * for potential resend! */ + send_again: #if ENABLE_DEBUG_TFTP - fprintf(stderr, "sending %u bytes\n", len); - for (cp = xbuf; cp < &xbuf[len]; cp++) + 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, len, &peer_lsa->sa, peer_lsa->len); + xsendto(socketfd, xbuf, send_len, &peer_lsa->sa, peer_lsa->len); + /* Was it final ACK? then exit */ + if (finished && (opcode == TFTP_ACK)) + goto ret; - if (finished && (opcode == TFTP_ACK)) { - break; - } - - /* receive packet */ + /* Receive packet */ recv_again: tv.tv_sec = TFTP_TIMEOUT; tv.tv_usec = 0; - FD_ZERO(&rfds); FD_SET(socketfd, &rfds); - switch (select(socketfd + 1, &rfds, NULL, NULL, &tv)) { unsigned from_port; case 1: @@ -280,7 +235,7 @@ static int tftp( &from->sa, &from->len); if (len < 0) { bb_perror_msg("recvfrom"); - break; + goto ret; } from_port = get_nport(&from->sa); if (port == org_port) { @@ -292,57 +247,57 @@ static int tftp( } if (port != from_port) goto recv_again; - timeout = 0; - break; + goto recvd_good; case 0: - bb_error_msg("timeout"); timeout--; if (timeout == 0) { - len = -1; bb_error_msg("last timeout"); + goto ret; } - break; + bb_error_msg("last timeout" + 5); + goto send_again; /* resend last sent pkt */ default: bb_perror_msg("select"); - len = -1; + goto ret; } + } /* while we don't see recv packet with correct port# */ - } while (timeout && (len >= 0)); - - if (finished || (len < 0)) { - break; - } - - /* process received packet */ - /* (both accesses seems to be aligned) */ - + /* Process recv'ed packet */ + recvd_good: opcode = ntohs( ((uint16_t*)rbuf)[0] ); - tmp = ntohs( ((uint16_t*)rbuf)[1] ); + recv_blk = ntohs( ((uint16_t*)rbuf)[1] ); #if ENABLE_DEBUG_TFTP - fprintf(stderr, "received %d bytes: %04x %04x\n", len, opcode, tmp); + fprintf(stderr, "received %d bytes: %04x %04x\n", len, opcode, recv_blk); #endif if (opcode == TFTP_ERROR) { - const char *msg = NULL; + 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", + }; + enum { NUM_ERRCODE = sizeof(errcode_str) / sizeof(errcode_str[0]) }; + + const char *msg = ""; if (rbuf[4] != '\0') { msg = &rbuf[4]; rbuf[tftp_bufsize - 1] = '\0'; - } else if (tmp < (sizeof(tftp_bb_error_msg) - / sizeof(char *))) { - msg = tftp_bb_error_msg[tmp]; - } - - if (msg) { - bb_error_msg("server says: %s", msg); + } else if (recv_blk < NUM_ERRCODE) { + msg = errcode_str[recv_blk]; } - - break; + 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) { @@ -350,87 +305,81 @@ static int tftp( 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)) { - if (CMD_PUT(cmd)) { - opcode = TFTP_DATA; - } else { - opcode = TFTP_ACK; - } + if (!tftp_blocksize_check(blksize, tftp_bufsize - 4)) { + bb_error_msg("server proposes bad blksize %d, exiting", blksize); + // FIXME: must also send ERROR 8 to server... + goto ret; + } #if ENABLE_DEBUG_TFTP - fprintf(stderr, "using blksize %u\n", - blksize); + fprintf(stderr, "using blksize %u\n", + blksize); #endif - tftp_bufsize = blksize + 4; - block_nr = 0; - continue; - } + tftp_bufsize = blksize + 4; + block_nr = 0; // TODO: explain why??? + continue; } - /* FIXME: - * we should send ERROR 8 */ - bb_error_msg("bad server option"); - break; + /* 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("warning: blksize not supported by server" - " - reverting to 512"); - + 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 (tmp == block_nr) { + if (recv_blk == block_nr) { len = full_write(localfd, &rbuf[4], len - 4); - if (len < 0) { bb_perror_msg(bb_msg_write_error); - break; + goto ret; } - if (len != (tftp_bufsize - 4)) { - finished++; + finished = 1; } - - opcode = TFTP_ACK; - continue; + continue; /* send ACK */ } - /* in case the last ack disappeared into the ether */ - if (tmp == (block_nr - 1)) { - --block_nr; - opcode = TFTP_ACK; - continue; -// tmp==(block_nr-1) and (tmp+1)==block_nr is always same, I think. wtf? - } else if (tmp + 1 == block_nr) { + if (recv_blk == (block_nr - 1)) { /* Server lost our TFTP_ACK. Resend it */ - block_nr = tmp; - opcode = TFTP_ACK; + block_nr = recv_blk; continue; - } + } } if (CMD_PUT(cmd) && (opcode == TFTP_ACK)) { - if (tmp == (uint16_t) (block_nr - 1)) { - if (finished) { - break; - } - - opcode = TFTP_DATA; - continue; + /* 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 ? EXIT_SUCCESS : EXIT_FAILURE; + return finished == 0; /* returns 1 on failure */ } int tftp_main(int argc, char **argv); @@ -458,6 +407,7 @@ int tftp_main(int argc, char **argv) "l:r:" USE_FEATURE_TFTP_BLOCKSIZE("b:"), &localfile, &remotefile USE_FEATURE_TFTP_BLOCKSIZE(, &sblocksize)); + argv += optind; flags = O_RDONLY; if (CMD_GET(cmd)) @@ -472,25 +422,26 @@ int tftp_main(int argc, char **argv) } #endif - if (localfile == NULL) + if (!localfile) localfile = remotefile; - if (remotefile == NULL) + if (!remotefile) remotefile = localfile; - if ((localfile == NULL && remotefile == NULL) || (argv[optind] == NULL)) + /* Error if filename or host is not known */ + if (!remotefile || !argv[0]) bb_show_usage(); - if (localfile == NULL || LONE_DASH(localfile)) { + if (LONE_DASH(localfile)) { fd = CMD_GET(cmd) ? STDOUT_FILENO : STDIN_FILENO; } else { - fd = xopen3(localfile, flags, 0644); + fd = xopen(localfile, flags); } - port = bb_lookup_port(argv[optind + 1], "udp", 69); - peer_lsa = xhost2sockaddr(argv[optind], port); + 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", + "remotefile \"%s\", localfile \"%s\"\n", xmalloc_sockaddr2dotted(&peer_lsa->sa, peer_lsa->len), remotefile, localfile); #endif @@ -501,11 +452,10 @@ int tftp_main(int argc, char **argv) #endif peer_lsa, remotefile, fd, port, blocksize); - if (fd > 1) { - if (ENABLE_FEATURE_CLEAN_UP) - close(fd); - if (CMD_GET(cmd) && result != EXIT_SUCCESS) - unlink(localfile); + if (ENABLE_FEATURE_CLEAN_UP) + close(fd); + if (result != EXIT_SUCCESS && !LONE_DASH(localfile) && CMD_GET(cmd)) { + unlink(localfile); } return result; } |