tftp: explain "block# 0" codepath; report our decision to bail out to server
if blocksize option doesn't look good (it was a FIXME. +33 bytes code);
make code more readable.
diff --git a/networking/tftp.c b/networking/tftp.c
index 1f1dfff..3fb76ec 100644
--- a/networking/tftp.c
+++ b/networking/tftp.c
@@ -37,15 +37,15 @@
#define TFTP_OACK 6
#if ENABLE_FEATURE_TFTP_GET && !ENABLE_FEATURE_TFTP_PUT
-#define USE_GETPUT(a)
+#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(a)
+#define USE_GETPUT(...)
#define CMD_GET(cmd) 0
#define CMD_PUT(cmd) 1
#else
-#define USE_GETPUT(a) a
+#define USE_GETPUT(...) __VA_ARGS__
/* masks coming from getpot32 */
#define CMD_GET(cmd) ((cmd) & 1)
#define CMD_PUT(cmd) ((cmd) & 2)
@@ -109,10 +109,7 @@
#endif
-static int tftp(
-#if ENABLE_FEATURE_TFTP_GET && ENABLE_FEATURE_TFTP_PUT
- const int cmd,
-#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)
@@ -181,6 +178,9 @@
/* 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;
@@ -203,67 +203,64 @@
send_pkt:
/* Send packet */
*((uint16_t*)xbuf) = htons(opcode); /* fill in opcode part */
- timeout = TFTP_NUM_RETRIES; /* re-initialize */
- while (1) {
- send_len = cp - xbuf;
- /* nb: need to preserve send_len value in code below
- * for potential resend! */
+ send_len = cp - xbuf;
+ /* NB: send_len value is preserved in code below
+ * for potential resend */
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");
+ 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;
+ xsendto(socketfd, xbuf, send_len, &peer_lsa->sa, peer_lsa->len);
+ /* Was it final ACK? then exit */
+ if (finished && (opcode == TFTP_ACK))
+ goto ret;
- /* Receive packet */
+ timeout = TFTP_NUM_RETRIES; /* re-initialize */
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:
- 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 recvd_good;
- case 0:
- timeout--;
- if (timeout == 0) {
- bb_error_msg("last timeout");
- goto ret;
- }
- bb_error_msg("last timeout" + 5);
- goto send_again; /* resend last sent pkt */
- default:
- bb_perror_msg("select");
+ /* Receive packet */
+ 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:
+ 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;
}
- } /* while we don't see recv packet with correct port# */
-
+ 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:
+ timeout--;
+ if (timeout == 0) {
+ bb_error_msg("last timeout");
+ goto ret;
+ }
+ bb_error_msg("last timeout" + 5);
+ goto send_again; /* resend last sent pkt */
+ default:
+ bb_perror_msg("select");
+ goto ret;
+ }
+ process_pkt:
/* Process recv'ed packet */
- recvd_good:
opcode = ntohs( ((uint16_t*)rbuf)[0] );
recv_blk = ntohs( ((uint16_t*)rbuf)[1] );
@@ -281,9 +278,9 @@
"unknown transfer id",
"file already exists",
"no such user",
+ "bad option",
};
enum { NUM_ERRCODE = sizeof(errcode_str) / sizeof(errcode_str[0]) };
-
const char *msg = "";
if (rbuf[4] != '\0') {
@@ -308,8 +305,13 @@
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 char 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);
- // FIXME: must also send ERROR 8 to server...
goto ret;
}
#if ENABLE_DEBUG_TFTP
@@ -317,7 +319,8 @@
blksize);
#endif
tftp_bufsize = blksize + 4;
- block_nr = 0; // TODO: explain why???
+ /* Send ACK for OACK ("block" no: 0) */
+ block_nr = 0;
continue;
}
/* rfc2347:
@@ -430,9 +433,8 @@
if (!remotefile || !argv[0])
bb_show_usage();
- if (LONE_DASH(localfile)) {
- fd = CMD_GET(cmd) ? STDOUT_FILENO : STDIN_FILENO;
- } else {
+ fd = CMD_GET(cmd) ? STDOUT_FILENO : STDIN_FILENO;
+ if (!LONE_DASH(localfile)) {
fd = xopen(localfile, flags);
}
@@ -440,17 +442,12 @@
peer_lsa = xhost2sockaddr(argv[0], port);
#if ENABLE_DEBUG_TFTP
- fprintf(stderr, "using server \"%s\", "
- "remotefile \"%s\", localfile \"%s\"\n",
+ fprintf(stderr, "using server '%s', remotefile '%s', localfile '%s'\n",
xmalloc_sockaddr2dotted(&peer_lsa->sa, peer_lsa->len),
remotefile, localfile);
#endif
- result = tftp(
-#if ENABLE_FEATURE_TFTP_GET && ENABLE_FEATURE_TFTP_PUT
- cmd,
-#endif
- peer_lsa, remotefile, fd, port, blocksize);
+ result = tftp( USE_GETPUT(cmd,) peer_lsa, remotefile, fd, port, blocksize);
if (ENABLE_FEATURE_CLEAN_UP)
close(fd);