(1) When sending the TFTP RRQ packet to read a file,

     send along the "blksize" option specified in RFC2348,
     and the "tsize" option specified in RFC2349.

     Add code to parse the TFTP Option Acknowledgement (OACK) packet as
     specified in RFC2347.

     For TFTP servers which support the "blksize" option, we can
     specify a TFTP Data block size larger than the default 512 bytes
     specified in RFC1350.  This offers greater read performance when
     downloading files.

     We request an initial size of 1428 bytes, which is less than the
     Ethernet MTU of 1500 bytes.  If the TFTP server sends back an OACK
     packet, then use the block size specified in the OACK packet.
     Most times it is usually the same value as what we request.
     If the TFTP server supports RFC2348, we will see performance improvements
     by transferring files over TFTP with larger block sizes.

     If we do not get back an OACK packet, then we most likely we
     are interoperating with a legacy TFTP server that does not
     support TFTP extension options, so default to the block size of
     512 bytes.

(2)  If the "tftp.blksize" environment variable is set, then
     take that value and use it when sending the TFTP RRQ packet,
     instead of 1428.  This allows us to set different values of
     "tftp.blksize" in the loader, so that we can test out different
     TFTP block sizes at run time.

Obtained from: Juniper Networks
Fixed by:  rodrigc

1 files changed, 229 insertions, 35 deletions

diff --git a/lib/libstand/tftp.c b/lib/libstand/tftp.c
index b8da31a..f34dfdb 100644
--- a/lib/libstand/tftp.c
+++ b/lib/libstand/tftp.c
@@ -60,13 +60,21 @@ __FBSDID("$FreeBSD$");
 
 #include "tftp.h"
 
+struct tftp_handle;
+
 static int	tftp_open(const char *path, struct open_file *f);
 static int	tftp_close(struct open_file *f);
+static void	tftp_parse_oack(struct tftp_handle *h, char *buf, size_t len);
 static int	tftp_read(struct open_file *f, void *buf, size_t size, size_t *resid);
 static int	tftp_write(struct open_file *f, void *buf, size_t size, size_t *resid);
 static off_t	tftp_seek(struct open_file *f, off_t offset, int where);
+static int	tftp_set_blksize(struct tftp_handle *h, const char *str);
 static int	tftp_stat(struct open_file *f, struct stat *sb);
-static ssize_t sendrecv_tftp(d, sproc, sbuf, ssize, rproc, rbuf, rsize);
+static ssize_t sendrecv_tftp(struct tftp_handle *h, 
+    ssize_t (*sproc)(struct iodesc *, void *, size_t),
+    void *sbuf, size_t ssize,
+    ssize_t (*rproc)(struct tftp_handle *h, void *, ssize_t, time_t, unsigned short *),
+    void *rbuf, size_t rsize, unsigned short *rtype);
 
 struct fs_ops tftp_fsops = {
 	"tftp",
@@ -82,8 +90,20 @@ struct fs_ops tftp_fsops = {
 extern struct in_addr servip;
 
 static int      tftpport = 2000;
+static int	is_open = 0;
+
+/*
+ * The legacy TFTP_BLKSIZE value was 512.
+ * TFTP_REQUESTED_BLKSIZE of 1428 is (Ethernet MTU, less the TFTP, UDP and
+ * IP header lengths).
+ */
+#define TFTP_REQUESTED_BLKSIZE 1428
 
-#define RSPACE 520		/* max data packet, rounded up */
+/*
+ * Choose a blksize big enough so we can test with Ethernet
+ * Jumbo frames in the future.
+ */ 
+#define TFTP_MAX_BLKSIZE 9008
 
 struct tftp_handle {
 	struct iodesc  *iodesc;
@@ -92,14 +112,16 @@ struct tftp_handle {
 	int             validsize;
 	int             off;
 	char           *path;	/* saved for re-requests */
+	unsigned int	tftp_blksize;
+	unsigned long	tftp_tsize; 
 	struct {
 		u_char header[HEADER_SIZE];
 		struct tftphdr t;
-		u_char space[RSPACE];
-	} __packed __aligned(4) lastdata;
+		u_char space[TFTP_MAX_BLKSIZE];
+	} lastdata;
 };
 
-static const int tftperrors[8] = {
+static int tftperrors[8] = {
 	0,			/* ??? */
 	ENOENT,
 	EPERM,
@@ -111,8 +133,10 @@ static const int tftperrors[8] = {
 };
 
 static ssize_t 
-recvtftp(struct iodesc *d, void *pkt, ssize_t len, time_t tleft)
+recvtftp(struct tftp_handle *h, void *pkt, ssize_t len, time_t tleft,
+    unsigned short *rtype)
 {
+	struct iodesc *d = h->iodesc;
 	struct tftphdr *t;
 
 	errno = 0;
@@ -123,6 +147,7 @@ recvtftp(struct iodesc *d, void *pkt, ssize_t len, time_t tleft)
 		return (-1);
 
 	t = (struct tftphdr *) pkt;
+	*rtype = ntohs(t->th_opcode);
 	switch (ntohs(t->th_opcode)) {
 	case DATA: {
 		int got;
@@ -155,6 +180,18 @@ recvtftp(struct iodesc *d, void *pkt, ssize_t len, time_t tleft)
 			errno = tftperrors[ntohs(t->th_code)];
 		}
 		return (-1);
+	case OACK: {
+		struct udphdr *uh;
+		int tftp_oack_len = len - sizeof(t->th_opcode); 
+		tftp_parse_oack(h, t->th_u.tu_stuff, tftp_oack_len);
+		/*
+		 * Remember which port this OACK came from,
+		 * because we need to send the ACK back to it.
+		 */
+		uh = (struct udphdr *) pkt - 1;
+		d->destport = uh->uh_sport;
+		return (0);
+	}
 	default:
 #ifdef TFTP_DEBUG
 		printf("tftp type %d not handled\n", ntohs(t->th_opcode));
@@ -171,19 +208,40 @@ tftp_makereq(struct tftp_handle *h)
 		u_char header[HEADER_SIZE];
 		struct tftphdr  t;
 		u_char space[FNAME_SIZE + 6];
-	} __packed __aligned(4) wbuf;
+	} wbuf;
 	char           *wtail;
 	int             l;
 	ssize_t         res;
 	struct tftphdr *t;
+	char *tftp_blksize = NULL;
+	int blksize_l;
+	unsigned short rtype = 0;
+
+	/*
+	 * Allow overriding default TFTP block size by setting
+	 * a tftp.blksize environment variable.
+	 */
+	if ((tftp_blksize = getenv("tftp.blksize")) != NULL) {
+		tftp_set_blksize(h, tftp_blksize);
+	}
 
 	wbuf.t.th_opcode = htons((u_short) RRQ);
 	wtail = wbuf.t.th_stuff;
 	l = strlen(h->path);
+	if (l > FNAME_SIZE)
+		return (ENAMETOOLONG);
 	bcopy(h->path, wtail, l + 1);
 	wtail += l + 1;
 	bcopy("octet", wtail, 6);
 	wtail += 6;
+	bcopy("blksize", wtail, 8);
+	wtail += 8;
+	blksize_l = sprintf(wtail, "%d", h->tftp_blksize);
+	wtail += blksize_l + 1;
+	bcopy("tsize", wtail, 6);
+	wtail += 6;
+	bcopy("0", wtail, 2);
+	wtail += 2;
 
 	t = &h->lastdata.t;
 
@@ -192,18 +250,33 @@ tftp_makereq(struct tftp_handle *h)
 	h->iodesc->destport = htons(IPPORT_TFTP);
 	h->iodesc->xid = 1;	/* expected block */
 
-	res = sendrecv_tftp(h->iodesc, sendudp, &wbuf.t, wtail - (char *) &wbuf.t,
-		       recvtftp, t, sizeof(*t) + RSPACE);
+	res = sendrecv_tftp(h, &sendudp, &wbuf.t, wtail - (char *) &wbuf.t,
+		       &recvtftp, t, sizeof(*t) + h->tftp_blksize, &rtype);
+
+	if (rtype == OACK) {
+		wbuf.t.th_opcode = htons((u_short)ACK);
+		wtail = (char *) &wbuf.t.th_block;
+		wbuf.t.th_block = htons(0);
+		wtail += 2;
+		rtype = 0;
+		res = sendrecv_tftp(h, &sendudp, &wbuf.t, wtail - (char *) &wbuf.t,
+			       &recvtftp, t, sizeof(*t) + h->tftp_blksize, &rtype);
+	}
 
-	if (res == -1)
-		return (errno);
+	switch (rtype) {
+		case DATA: {
+			h->currblock = 1;
+			h->validsize = res;
+			h->islastblock = 0;
+			if (res < h->tftp_blksize)
+				h->islastblock = 1;	/* very short file */
+			return (0);
+		}
+		case ERROR:
+		default:
+			return (errno);
+	}
 
-	h->currblock = 1;
-	h->validsize = res;
-	h->islastblock = 0;
-	if (res < SEGSIZE)
-		h->islastblock = 1;	/* very short file */
-	return (0);
 }
 
 /* ack block, expect next */
@@ -213,11 +286,11 @@ tftp_getnextblock(struct tftp_handle *h)
 	struct {
 		u_char header[HEADER_SIZE];
 		struct tftphdr t;
-	} __packed __aligned(4) wbuf;
+	} wbuf;
 	char           *wtail;
 	int             res;
 	struct tftphdr *t;
-
+	unsigned short rtype = 0;
 	wbuf.t.th_opcode = htons((u_short) ACK);
 	wtail = (char *) &wbuf.t.th_block;
 	wbuf.t.th_block = htons((u_short) h->currblock);
@@ -227,16 +300,23 @@ tftp_getnextblock(struct tftp_handle *h)
 
 	h->iodesc->xid = h->currblock + 1;	/* expected block */
 
-	res = sendrecv_tftp(h->iodesc, sendudp, &wbuf.t, wtail - (char *) &wbuf.t,
-		       recvtftp, t, sizeof(*t) + RSPACE);
+	res = sendrecv_tftp(h, &sendudp, &wbuf.t, wtail - (char *) &wbuf.t,
+		       &recvtftp, t, sizeof(*t) + h->tftp_blksize, &rtype);
 
 	if (res == -1)		/* 0 is OK! */
 		return (errno);
 
 	h->currblock++;
 	h->validsize = res;
-	if (res < SEGSIZE)
+	if (res < h->tftp_blksize)
 		h->islastblock = 1;	/* EOF */
+
+	if (h->islastblock == 1) {
+		/* Send an ACK for the last block */ 
+		wbuf.t.th_block = htons((u_short) h->currblock);
+		sendudp(h->iodesc, &wbuf.t, wtail - (char *)&wbuf.t);
+	}
+
 	return (0);
 }
 
@@ -252,10 +332,15 @@ tftp_open(const char *path, struct open_file *f)
 		return (EINVAL);
 #endif
 
+	if (is_open)
+		return (EBUSY);
+
 	tftpfile = (struct tftp_handle *) malloc(sizeof(*tftpfile));
 	if (!tftpfile)
 		return (ENOMEM);
 
+	memset(tftpfile, 0, sizeof(*tftpfile));
+	tftpfile->tftp_blksize = TFTP_REQUESTED_BLKSIZE;
 	tftpfile->iodesc = io = socktodesc(*(int *) (f->f_devdata));
 	if (io == NULL)
 		return (EINVAL);
@@ -276,6 +361,7 @@ tftp_open(const char *path, struct open_file *f)
 		return (res);
 	}
 	f->f_fsdata = (void *) tftpfile;
+	is_open = 1;
 	return (0);
 }
 
@@ -293,7 +379,7 @@ tftp_read(struct open_file *f, void *addr, size_t size,
 		if (!(tc++ % 16))
 			twiddle();
 
-		needblock = tftpfile->off / SEGSIZE + 1;
+		needblock = tftpfile->off / tftpfile->tftp_blksize + 1;
 
 		if (tftpfile->currblock > needblock)	/* seek backwards */
 			tftp_makereq(tftpfile);	/* no error check, it worked
@@ -316,7 +402,7 @@ tftp_read(struct open_file *f, void *addr, size_t size,
 		if (tftpfile->currblock == needblock) {
 			int offinblock, inbuffer;
 
-			offinblock = tftpfile->off % SEGSIZE;
+			offinblock = tftpfile->off % tftpfile->tftp_blksize;
 
 			inbuffer = tftpfile->validsize - offinblock;
 			if (inbuffer < 0) {
@@ -362,18 +448,19 @@ tftp_close(struct open_file *f)
 		free(tftpfile->path);
 		free(tftpfile);
 	}
+	is_open = 0;
 	return (0);
 }
 
 static int 
 tftp_write(struct open_file *f __unused, void *start __unused, size_t size __unused,
-    size_t *resid /* out */ __unused)
+    size_t *resid __unused /* out */)
 {
 	return (EROFS);
 }
 
 static int 
-tftp_stat(struct open_file *f, struct stat    *sb)
+tftp_stat(struct open_file *f, struct stat *sb)
 {
 	struct tftp_handle *tftpfile;
 	tftpfile = (struct tftp_handle *) f->f_fsdata;
@@ -407,15 +494,13 @@ tftp_seek(struct open_file *f, off_t offset, int where)
 }
 
 static ssize_t
-sendrecv_tftp(d, sproc, sbuf, ssize, rproc, rbuf, rsize)
-	struct iodesc *d;
-	ssize_t (*sproc)(struct iodesc *, void *, size_t);
-	void *sbuf;
-	size_t ssize;
-	ssize_t (*rproc)(struct iodesc *, void *, size_t, time_t);
-	void *rbuf;
-	size_t rsize;
+sendrecv_tftp(struct tftp_handle *h, 
+    ssize_t (*sproc)(struct iodesc *, void *, size_t),
+    void *sbuf, size_t ssize,
+    ssize_t (*rproc)(struct tftp_handle *, void *, ssize_t, time_t, unsigned short *),
+    void *rbuf, size_t rsize, unsigned short *rtype)
 {
+	struct iodesc *d = h->iodesc;
 	ssize_t cc;
 	time_t t, t1, tleft;
 
@@ -445,7 +530,7 @@ sendrecv_tftp(d, sproc, sbuf, ssize, rproc, rbuf, rsize)
 
 recvnext:
 		/* Try to get a packet and process it. */
-		cc = (*rproc)(d, rbuf, rsize, tleft);
+		cc = (*rproc)(h, rbuf, rsize, tleft, rtype);
 		/* Return on data, EOF or real error. */
 		if (cc != -1 || errno != 0)
 			return (cc);
@@ -461,3 +546,112 @@ recvnext:
 		t1 = getsecs();
 	}
 }
+
+static int
+tftp_set_blksize(struct tftp_handle *h, const char *str)
+{
+        char *endptr;
+	int new_blksize;
+	int ret = 0;
+
+	if (h == NULL || str == NULL)
+		return (ret);
+
+	new_blksize =
+	    (unsigned int)strtol(str, &endptr, 0);
+
+	/*
+	 * Only accept blksize value if it is numeric.
+	 * RFC2348 specifies that acceptable valuesare 8-65464
+	 * 8-65464 .  Let's choose a limit less than MAXRSPACE
+	*/
+	if (*endptr == '\0' && new_blksize >= 8
+	    && new_blksize <= TFTP_MAX_BLKSIZE) {
+		h->tftp_blksize = new_blksize;
+		ret = 1;
+	}
+
+	return (ret);
+}
+
+/*
+ * In RFC2347, the TFTP Option Acknowledgement package (OACK)
+ * is used to acknowledge a client's option negotiation request.
+ * The format of an OACK packet is:
+ *    +-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+
+ *    |  opc  |  opt1  | 0 | value1 | 0 |  optN  | 0 | valueN | 0 |
+ *    +-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+
+ *
+ *    opc
+ *       The opcode field contains a 6, for Option Acknowledgment.
+ *
+ *    opt1
+ *       The first option acknowledgment, copied from the original
+ *       request.
+ *
+ *    value1
+ *       The acknowledged value associated with the first option.  If
+ *       and how this value may differ from the original request is
+ *       detailed in the specification for the option.
+ *
+ *    optN, valueN
+ *       The final option/value acknowledgment pair.
+ */
+static void 
+tftp_parse_oack(struct tftp_handle *h, char *buf, size_t len)
+{
+	/* 
+	 *  We parse the OACK strings into an array
+	 *  of name-value pairs.
+	 *  
+	 */
+	char *tftp_options[128] = { 0 };
+	char *val = buf;
+	int i = 0;
+	int option_idx = 0;
+	int blksize_is_set = 0;
+	int tsize = 0;
+	
+ 
+	while ( option_idx < 128 && i < len ) {
+		 if (buf[i] == '\0') {
+		    if (&buf[i] > val) {
+		       tftp_options[option_idx] = val;
+		       val = &buf[i] + 1;
+		       ++option_idx;
+		    }
+		 }
+		 ++i;
+	}
+
+	/* 
+	 * Parse individual TFTP options.
+	 *    * "blksize" is specified in RFC2348.
+	 *    * "tsize" is specified in RFC2349.
+	 */ 
+	for (i = 0; i < option_idx; i += 2) {
+	    if (strcasecmp(tftp_options[i], "blksize") == 0) {
+		if (i + 1 < option_idx) {
+			blksize_is_set =
+			    tftp_set_blksize(h, tftp_options[i + 1]);
+		}
+	    } else if (strcasecmp(tftp_options[i], "tsize") == 0) {
+		if (i + 1 < option_idx) {
+			tsize = strtol(tftp_options[i + 1], (char **)NULL, 10);
+		}
+	    }
+	}
+
+	if (!blksize_is_set) {
+		/*
+		 * If TFTP blksize was not set, try defaulting
+		 * to the legacy TFTP blksize of 512
+		 */
+		h->tftp_blksize = 512;
+	}
+
+#ifdef TFTP_DEBUG
+	printf("tftp_blksize: %u\n", h->tftp_blksize);
+	printf("tftp_tsize: %lu\n", h->tftp_tsize);
+#endif
+}