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tftp: code diet, and I think retransmits were broken.

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function                                             old     new   delta
static.errcode_str                                     -      32     +32
tftp_main                                            359     345     -14
tftp_bb_error_msg                                     32       -     -32
.rodata                                           130931  130899     -32
tftp                                                1720    1558    -162
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 0/3 up/down: 32/-240)          Total: -208 bytes
This commit is contained in:
Denis Vlasenko 2007-05-08 23:12:21 +00:00
parent 7e84e539de
commit a04561f5f7
1 changed files with 160 additions and 210 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

370
networking/tftp.c
View File

@ -36,17 +36,6 @@
#define TFTP_ERROR 5 #define TFTP_ERROR 5
#define TFTP_OACK 6 #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 #if ENABLE_FEATURE_TFTP_GET && !ENABLE_FEATURE_TFTP_PUT
#define USE_GETPUT(a) #define USE_GETPUT(a)
#define CMD_GET(cmd) 1 #define CMD_GET(cmd) 1
@ -62,7 +51,7 @@ static const char *const tftp_bb_error_msg[] = {
#define CMD_PUT(cmd) ((cmd) & 2) #define CMD_PUT(cmd) ((cmd) & 2)
#endif #endif
/* NB: in the code below /* 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; 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_val = 0;
int opt_found = 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) { while (len > 0) {
/* Make sure the options are terminated correctly */ /* Make sure the options are terminated correctly */
for (k = 0; k < len; k++) { for (k = 0; k < len; k++) {
if (buf[k] == '\0') { if (buf[k] == '\0') {
break; goto nul_found;
} }
} }
return NULL;
if (k >= len) { nul_found:
break;
}
if (opt_val == 0) { if (opt_val == 0) {
if (strcasecmp(buf, option) == 0) { if (strcasecmp(buf, option) == 0) {
opt_found = 1; opt_found = 1;
} }
} else { } else if (opt_found) {
if (opt_found) { return buf;
return buf;
}
} }
k++; k++;
buf += k; buf += k;
len -= k; len -= k;
opt_val ^= 1; opt_val ^= 1;
} }
@ -140,15 +121,15 @@ static int tftp(
fd_set rfds; fd_set rfds;
int socketfd; int socketfd;
int len; int len;
int opcode = 0; int send_len;
int finished = 0; USE_FEATURE_TFTP_BLOCKSIZE(smallint want_option_ack = 0;)
int timeout = TFTP_NUM_RETRIES; smallint finished = 0;
uint16_t opcode;
uint16_t block_nr = 1; uint16_t block_nr = 1;
uint16_t tmp; uint16_t recv_blk;
int timeout = TFTP_NUM_RETRIES;
char *cp; char *cp;
USE_FEATURE_TFTP_BLOCKSIZE(int want_option_ack = 0;)
unsigned org_port; unsigned org_port;
len_and_sockaddr *const from = alloca(offsetof(len_and_sockaddr, sa) + peer_lsa->len); 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)) { if (CMD_GET(cmd)) {
opcode = TFTP_RRQ; opcode = TFTP_RRQ;
} }
cp = xbuf + 2;
while (1) { /* add filename and mode */
cp = xbuf; /* fill in packet if the filename fits into xbuf */
len = strlen(remotefile) + 1;
/* first create the opcode part */ if (2 + len + sizeof("octet") >= tftp_bufsize) {
/* (this 16bit store is aligned) */ bb_error_msg("remote filename is too long");
*((uint16_t*)cp) = htons(opcode); goto ret;
cp += 2; }
strcpy(cp, remotefile);
/* add filename and mode */ cp += len;
if (CMD_GET(cmd) ? (opcode == TFTP_RRQ) : (opcode == TFTP_WRQ)) { /* add "mode" part of the package */
int too_long = 0; strcpy(cp, "octet");
cp += sizeof("octet");
/* 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");
#if ENABLE_FEATURE_TFTP_BLOCKSIZE #if ENABLE_FEATURE_TFTP_BLOCKSIZE
len = tftp_bufsize - 4; /* data block size */
len = tftp_bufsize - 4; /* data block size */ if (len != TFTP_BLOCKSIZE_DEFAULT) {
/* rfc2348 says that 65464 is a max allowed value */
if (len != TFTP_BLOCKSIZE_DEFAULT) { if ((&xbuf[tftp_bufsize - 1] - cp) < sizeof("blksize NNNNN")) {
bb_error_msg("remote filename is too long");
if ((&xbuf[tftp_bufsize - 1] - cp) < 15) { goto ret;
bb_error_msg("remote filename too long"); }
break; /* add "blksize", <nul>, blocksize */
} strcpy(cp, "blksize");
cp += sizeof("blksize");
/* add "blksize" + number of blocks */ cp += snprintf(cp, 6, "%d", len) + 1;
memcpy(cp, "blksize", sizeof("blksize")); want_option_ack = 1;
cp += sizeof("blksize"); }
cp += snprintf(cp, 6, "%d", len) + 1;
want_option_ack = 1;
}
#endif #endif
} /* First packet is built, so skip packet generation */
goto send_pkt;
/* add ack and data */ while (1) {
/* Build ACK or DATA */
if (CMD_GET(cmd) ? (opcode == TFTP_ACK) : (opcode == TFTP_DATA)) { cp = xbuf + 2;
/* TODO: unaligned access! */ *((uint16_t*)cp) = htons(block_nr);
*((uint16_t*)cp) = htons(block_nr); cp += 2;
cp += 2; block_nr++;
block_nr++; opcode = TFTP_ACK;
if (CMD_PUT(cmd)) {
if (CMD_PUT(cmd) && (opcode == TFTP_DATA)) { opcode = TFTP_DATA;
len = full_read(localfd, cp, tftp_bufsize - 4); len = full_read(localfd, cp, tftp_bufsize - 4);
if (len < 0) {
if (len < 0) { bb_perror_msg(bb_msg_read_error);
bb_perror_msg(bb_msg_read_error); goto ret;
break;
}
if (len != (tftp_bufsize - 4)) {
finished++;
}
cp += len;
} }
if (len != (tftp_bufsize - 4)) {
finished = 1;
}
cp += len;
} }
send_pkt:
/* send packet */ /* Send packet */
*((uint16_t*)xbuf) = htons(opcode); /* fill in opcode part */
timeout = TFTP_NUM_RETRIES; /* re-initialize */ timeout = TFTP_NUM_RETRIES; /* re-initialize */
do { while (1) {
len = cp - xbuf; send_len = cp - xbuf;
/* nb: need to preserve send_len value in code below
* for potential resend! */
send_again:
#if ENABLE_DEBUG_TFTP #if ENABLE_DEBUG_TFTP
fprintf(stderr, "sending %u bytes\n", len); fprintf(stderr, "sending %u bytes\n", send_len);
for (cp = xbuf; cp < &xbuf[len]; cp++) for (cp = xbuf; cp < &xbuf[send_len]; cp++)
fprintf(stderr, "%02x ", (unsigned char) *cp); fprintf(stderr, "%02x ", (unsigned char) *cp);
fprintf(stderr, "\n"); fprintf(stderr, "\n");
#endif #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)) { /* Receive packet */
break;
}
/* receive packet */
recv_again: recv_again:
tv.tv_sec = TFTP_TIMEOUT; tv.tv_sec = TFTP_TIMEOUT;
tv.tv_usec = 0; tv.tv_usec = 0;
FD_ZERO(&rfds); FD_ZERO(&rfds);
FD_SET(socketfd, &rfds); FD_SET(socketfd, &rfds);
switch (select(socketfd + 1, &rfds, NULL, NULL, &tv)) { switch (select(socketfd + 1, &rfds, NULL, NULL, &tv)) {
unsigned from_port; unsigned from_port;
case 1: case 1:
@ -280,7 +235,7 @@ static int tftp(
&from->sa, &from->len); &from->sa, &from->len);
if (len < 0) { if (len < 0) {
bb_perror_msg("recvfrom"); bb_perror_msg("recvfrom");
break; goto ret;
} }
from_port = get_nport(&from->sa); from_port = get_nport(&from->sa);
if (port == org_port) { if (port == org_port) {
@ -292,57 +247,57 @@ static int tftp(
} }
if (port != from_port) if (port != from_port)
goto recv_again; goto recv_again;
timeout = 0; goto recvd_good;
break;
case 0: case 0:
bb_error_msg("timeout");
timeout--; timeout--;
if (timeout == 0) { if (timeout == 0) {
len = -1;
bb_error_msg("last timeout"); bb_error_msg("last timeout");
goto ret;
} }
break; bb_error_msg("last timeout" + 5);
goto send_again; /* resend last sent pkt */
default: default:
bb_perror_msg("select"); bb_perror_msg("select");
len = -1; goto ret;
} }
} /* while we don't see recv packet with correct port# */
} while (timeout && (len >= 0)); /* Process recv'ed packet */
recvd_good:
if (finished || (len < 0)) {
break;
}
/* process received packet */
/* (both accesses seems to be aligned) */
opcode = ntohs( ((uint16_t*)rbuf)[0] ); opcode = ntohs( ((uint16_t*)rbuf)[0] );
tmp = ntohs( ((uint16_t*)rbuf)[1] ); recv_blk = ntohs( ((uint16_t*)rbuf)[1] );
#if ENABLE_DEBUG_TFTP #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 #endif
if (opcode == TFTP_ERROR) { 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') { if (rbuf[4] != '\0') {
msg = &rbuf[4]; msg = &rbuf[4];
rbuf[tftp_bufsize - 1] = '\0'; rbuf[tftp_bufsize - 1] = '\0';
} else if (tmp < (sizeof(tftp_bb_error_msg) } else if (recv_blk < NUM_ERRCODE) {
/ sizeof(char *))) { msg = errcode_str[recv_blk];
msg = tftp_bb_error_msg[tmp];
} }
bb_error_msg("server error: (%u) %s", recv_blk, msg);
if (msg) { goto ret;
bb_error_msg("server says: %s", msg);
}
break;
} }
#if ENABLE_FEATURE_TFTP_BLOCKSIZE #if ENABLE_FEATURE_TFTP_BLOCKSIZE
if (want_option_ack) { if (want_option_ack) {
want_option_ack = 0; want_option_ack = 0;
if (opcode == TFTP_OACK) { if (opcode == TFTP_OACK) {
@ -350,87 +305,81 @@ static int tftp(
char *res; char *res;
res = tftp_option_get(&rbuf[2], len - 2, "blksize"); res = tftp_option_get(&rbuf[2], len - 2, "blksize");
if (res) { if (res) {
int blksize = xatoi_u(res); int blksize = xatoi_u(res);
if (!tftp_blocksize_check(blksize, tftp_bufsize - 4)) {
if (tftp_blocksize_check(blksize, tftp_bufsize - 4)) { bb_error_msg("server proposes bad blksize %d, exiting", blksize);
if (CMD_PUT(cmd)) { // FIXME: must also send ERROR 8 to server...
opcode = TFTP_DATA; goto ret;
} else {
opcode = TFTP_ACK;
}
#if ENABLE_DEBUG_TFTP
fprintf(stderr, "using blksize %u\n",
blksize);
#endif
tftp_bufsize = blksize + 4;
block_nr = 0;
continue;
} }
#if ENABLE_DEBUG_TFTP
fprintf(stderr, "using blksize %u\n",
blksize);
#endif
tftp_bufsize = blksize + 4;
block_nr = 0; // TODO: explain why???
continue;
} }
/* FIXME: /* rfc2347:
* we should send ERROR 8 */ * "An option not acknowledged by the server
bb_error_msg("bad server option"); * must be ignored by the client and server
break; * as if it were never requested." */
} }
bb_error_msg("warning: blksize not supported by server" bb_error_msg("blksize is not supported by server"
" - reverting to 512"); " - reverting to 512");
tftp_bufsize = TFTP_BLOCKSIZE_DEFAULT + 4; tftp_bufsize = TFTP_BLOCKSIZE_DEFAULT + 4;
} }
#endif #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 (CMD_GET(cmd) && (opcode == TFTP_DATA)) {
if (tmp == block_nr) { if (recv_blk == block_nr) {
len = full_write(localfd, &rbuf[4], len - 4); len = full_write(localfd, &rbuf[4], len - 4);
if (len < 0) { if (len < 0) {
bb_perror_msg(bb_msg_write_error); bb_perror_msg(bb_msg_write_error);
break; goto ret;
} }
if (len != (tftp_bufsize - 4)) { if (len != (tftp_bufsize - 4)) {
finished++; finished = 1;
} }
continue; /* send ACK */
opcode = TFTP_ACK;
continue;
} }
/* in case the last ack disappeared into the ether */ if (recv_blk == (block_nr - 1)) {
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) {
/* Server lost our TFTP_ACK. Resend it */ /* Server lost our TFTP_ACK. Resend it */
block_nr = tmp; block_nr = recv_blk;
opcode = TFTP_ACK;
continue; continue;
} }
} }
if (CMD_PUT(cmd) && (opcode == TFTP_ACK)) { if (CMD_PUT(cmd) && (opcode == TFTP_ACK)) {
if (tmp == (uint16_t) (block_nr - 1)) { /* did server ACK our last DATA pkt? */
if (finished) { if (recv_blk == (uint16_t) (block_nr - 1)) {
break; if (finished)
} goto ret;
continue; /* send next block */
opcode = TFTP_DATA;
continue;
} }
} }
/* 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) { if (ENABLE_FEATURE_CLEAN_UP) {
close(socketfd); close(socketfd);
free(xbuf); free(xbuf);
free(rbuf); free(rbuf);
} }
return finished == 0; /* returns 1 on failure */
return finished ? EXIT_SUCCESS : EXIT_FAILURE;
} }
int tftp_main(int argc, char **argv); 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:"), "l:r:" USE_FEATURE_TFTP_BLOCKSIZE("b:"),
&localfile, &remotefile &localfile, &remotefile
USE_FEATURE_TFTP_BLOCKSIZE(, &sblocksize)); USE_FEATURE_TFTP_BLOCKSIZE(, &sblocksize));
argv += optind;
flags = O_RDONLY; flags = O_RDONLY;
if (CMD_GET(cmd)) if (CMD_GET(cmd))
@ -472,25 +422,26 @@ int tftp_main(int argc, char **argv)
} }
#endif #endif
if (localfile == NULL) if (!localfile)
localfile = remotefile; localfile = remotefile;
if (remotefile == NULL) if (!remotefile)
remotefile = localfile; 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(); bb_show_usage();
if (localfile == NULL || LONE_DASH(localfile)) { if (LONE_DASH(localfile)) {
fd = CMD_GET(cmd) ? STDOUT_FILENO : STDIN_FILENO; fd = CMD_GET(cmd) ? STDOUT_FILENO : STDIN_FILENO;
} else { } else {
fd = xopen3(localfile, flags, 0644); fd = xopen(localfile, flags);
} }
port = bb_lookup_port(argv[optind + 1], "udp", 69); port = bb_lookup_port(argv[1], "udp", 69);
peer_lsa = xhost2sockaddr(argv[optind], port); peer_lsa = xhost2sockaddr(argv[0], port);
#if ENABLE_DEBUG_TFTP #if ENABLE_DEBUG_TFTP
fprintf(stderr, "using server \"%s\", " fprintf(stderr, "using server \"%s\", "
"remotefile \"%s\", localfile \"%s\".\n", "remotefile \"%s\", localfile \"%s\"\n",
xmalloc_sockaddr2dotted(&peer_lsa->sa, peer_lsa->len), xmalloc_sockaddr2dotted(&peer_lsa->sa, peer_lsa->len),
remotefile, localfile); remotefile, localfile);
#endif #endif
@ -501,11 +452,10 @@ int tftp_main(int argc, char **argv)
#endif #endif
peer_lsa, remotefile, fd, port, blocksize); peer_lsa, remotefile, fd, port, blocksize);
if (fd > 1) { if (ENABLE_FEATURE_CLEAN_UP)
if (ENABLE_FEATURE_CLEAN_UP) close(fd);
close(fd); if (result != EXIT_SUCCESS && !LONE_DASH(localfile) && CMD_GET(cmd)) {
if (CMD_GET(cmd) && result != EXIT_SUCCESS) unlink(localfile);
unlink(localfile);
} }
return result; return result;
} }