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Implement TFTP blksize option
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@jclehner
jclehner committed Jan 6, 2017
1 parent 77359d4 commit 79f3c1f
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Showing 2 changed files with 117 additions and 23 deletions.
3 changes: 3 additions & 0 deletions Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,9 @@ nmrpflash_OBJ = nmrp.o tftp.o ethsock.o main.o util.o
nmrpflash: $(nmrpflash_OBJ)
$(CC) $(CFLAGS) -o nmrpflash $(nmrpflash_OBJ) $(LDFLAGS)

tftptest:
CFLAGS=-DNMRPFLASH_TFTP_TEST make clean nmrpflash

%.o: %.c nmrpd.h
$(CC) -c $(CFLAGS) $< -o $@

Expand Down
137 changes: 114 additions & 23 deletions tftp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,15 +33,16 @@
#define TFTP_PKT_SIZE 516

static const char *opcode_names[] = {
"RRQ", "WRQ", "DATA", "ACK", "ERR"
"RRQ", "WRQ", "DATA", "ACK", "ERR", "OACK"
};

enum tftp_opcode {
RRQ = 1,
WRQ = 2,
DATA = 3,
ACK = 4,
ERR = 5
ERR = 5,
OACK = 6
};

static bool is_netascii(const char *str)
Expand All @@ -67,7 +68,70 @@ static inline uint16_t pkt_num(char *pkt)
return ntohs(*(uint16_t*)pkt);
}

static void pkt_mkwrq(char *pkt, const char *filename)
static char *pkt_mkopt(char *pkt, const char *opt, const char* val)
{
strcpy(pkt, opt);
pkt += strlen(pkt) + 1;
strcpy(pkt, val);
pkt += strlen(val) + 1;
return pkt;
}

static bool pkt_nextstr(char **pkt, char **str, size_t *rem)
{
size_t len;

if (!isprint(**pkt) || !(len = strnlen(*pkt, *rem))) {
return false;
}

*str = *pkt;
*pkt += len + 1;

if (*rem > 1) {
*rem -= len + 1;
} else {
*rem = 0;
}

return true;
}

static bool pkt_nextopt(char **pkt, char **opt, char **val, size_t *rem)
{
return pkt_nextstr(pkt, opt, rem) && pkt_nextstr(pkt, val, rem);
}

static char *pkt_optval(char* pkt, const char* name)
{
size_t rem = 512;
char *opt, *val;
pkt += 2;

while (pkt_nextopt(&pkt, &opt, &val, &rem)) {
if (!strcmp(name, opt)) {
return val;
}
}

return NULL;
}

static size_t pkt_xrqlen(char *pkt)
{
size_t len = 2, rem = 512;
char *opt, *val;

pkt += 2;

while (pkt_nextopt(&pkt, &opt, &val, &rem)) {
len += strlen(opt) + strlen(val) + 2;
}

return len;
}

static void pkt_mkwrq(char *pkt, const char *filename, unsigned blksize)
{
size_t len = 2;

Expand All @@ -80,29 +144,41 @@ static void pkt_mkwrq(char *pkt, const char *filename)
}

pkt_mknum(pkt, WRQ);
pkt = pkt_mkopt(pkt + 2, filename, "octet");

strcpy(pkt + len, filename);
len += strlen(filename) + 1;
strcpy(pkt + len, "octet");
if (blksize && blksize != 512) {
pkt = pkt_mkopt(pkt, "blksize", lltostr(blksize, 10));
}
}

static inline void pkt_print(char *pkt, FILE *fp)
{
uint16_t opcode = pkt_num(pkt);
if (!opcode || opcode > ERR) {
size_t rem;
char *opt, *val;

if (!opcode || opcode > OACK) {
fprintf(fp, "(%d)", opcode);
} else {
fprintf(fp, "%s", opcode_names[opcode - 1]);
if (opcode == ACK || opcode == DATA) {
fprintf(fp, "(%d)", pkt_num(pkt + 2));
} else if (opcode == WRQ || opcode == RRQ) {
fprintf(fp, "(%s, %s)", pkt + 2, pkt + 2 + strlen(pkt + 2) + 1);
} else if (opcode == OACK) {
fprintf(fp, "(");
rem = 512;
pkt += 2;
while (pkt_nextopt(&pkt, &opt, &val, &rem)) {
fprintf(fp, " %s=%s ", opt, val);
}
fprintf(fp, ")");
}
}
}

static ssize_t tftp_recvfrom(int sock, char *pkt, uint16_t* port,
unsigned timeout)
unsigned timeout, size_t blksize)
{
ssize_t len;
struct sockaddr_in src;
Expand All @@ -120,7 +196,7 @@ static ssize_t tftp_recvfrom(int sock, char *pkt, uint16_t* port,
}

alen = sizeof(src);
len = recvfrom(sock, pkt, TFTP_PKT_SIZE, 0, (struct sockaddr*)&src, &alen);
len = recvfrom(sock, pkt, blksize, 0, (struct sockaddr*)&src, &alen);
if (len < 0) {
sock_perror("recvfrom");
return -1;
Expand All @@ -140,7 +216,7 @@ static ssize_t tftp_recvfrom(int sock, char *pkt, uint16_t* port,
*/
fprintf(stderr, "Error: %.32s\n", pkt);
return -2;
} else if (!opcode || opcode > ERR) {
} else if (!opcode || opcode > OACK) {
fprintf(stderr, "Received invalid packet: ");
pkt_print(pkt, stderr);
fprintf(stderr, ".\n");
Expand All @@ -164,8 +240,7 @@ static ssize_t tftp_sendto(int sock, char *pkt, size_t len,
switch (pkt_num(pkt)) {
case RRQ:
case WRQ:
len = 2 + strlen(pkt + 2) + 1;
len += strlen(pkt + len) + 1;
len = pkt_xrqlen(pkt);
break;
case DATA:
len += 4;
Expand Down Expand Up @@ -230,11 +305,12 @@ inline bool tftp_is_valid_filename(const char *filename)
int tftp_put(struct nmrpd_args *args)
{
struct sockaddr_in addr;
uint16_t block, port;
uint16_t block, port, op, blksize;
ssize_t len, last_len;
int fd, sock, ret, timeout, errors, ackblock;
char rx[TFTP_PKT_SIZE], tx[TFTP_PKT_SIZE];
char rx[2048], tx[2048];
const char *file_remote = args->file_remote;
char *p;

sock = -1;
ret = -1;
Expand Down Expand Up @@ -289,34 +365,49 @@ int tftp_put(struct nmrpd_args *args)
}
addr.sin_port = htons(args->port);

blksize = 1468;
block = 0;
last_len = -1;
len = 0;
errors = 0;
/* Not really, but this way the loop sends our WRQ before receiving */
timeout = 1;

pkt_mkwrq(tx, file_remote);
pkt_mkwrq(tx, file_remote, blksize);

while (!g_interrupted) {
if (!timeout && pkt_num(rx) == ACK) {
ackblock = pkt_num(rx + 2);
} else {
ackblock = -1;
ackblock = -1;
op = pkt_num(rx);

if (!timeout) {
if (pkt_num(rx) == ACK) {
ackblock = pkt_num(rx + 2);
if (!ackblock) {
blksize = 512;
}
} else if (pkt_num(rx) == OACK) {
op = ACK;
ackblock = 0;
if ((p = pkt_optval(rx, "blksize"))) {
blksize = atoi(p);
} else {
blksize = 512;
}
}
}

if (timeout || ackblock == block) {
if (!timeout) {
++block;
pkt_mknum(tx, DATA);
pkt_mknum(tx + 2, block);
len = read(fd, tx + 4, 512);
len = read(fd, tx + 4, blksize);
if (len < 0) {
xperror("read");
ret = len;
goto cleanup;
} else if (!len) {
if (last_len != 512 && last_len != -1) {
if (last_len != blksize && last_len != -1) {
break;
}
}
Expand All @@ -328,7 +419,7 @@ int tftp_put(struct nmrpd_args *args)
if (ret < 0) {
goto cleanup;
}
} else if (pkt_num(rx) != ACK || ackblock > block) {
} else if (op != ACK || ackblock > block) {
if (verbosity) {
fprintf(stderr, "Expected ACK(%d), got ", block);
pkt_print(rx, stderr);
Expand All @@ -342,7 +433,7 @@ int tftp_put(struct nmrpd_args *args)
}
}

ret = tftp_recvfrom(sock, rx, &port, args->rx_timeout);
ret = tftp_recvfrom(sock, rx, &port, args->rx_timeout, blksize + 2);
if (ret < 0) {
goto cleanup;
} else if (!ret) {
Expand Down

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