lwip: tftp: resend initial request

The TFTP implementation does not resend the initial request if there is
no response from the server. Since TFTP is based on UDP, there should be
a mechanism to deal with unreliable transmissions at this point, similar
to what we have for data packets. Therefore, introduce request
retransmission.

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
CC: Venkatesh Abbarapu <venkatesh.abbarapu@amd.com>
CC: Michal Simek <michal.simek@amd.com>
CC: Ilias Apalodimas <ilias.apalodimas@linaro.org>
This commit is contained in:
Jerome Forissier 2025-07-24 18:08:24 +02:00
parent 512be89796
commit 46fc565599

View File

@ -79,6 +79,14 @@ enum tftp_error {
#include <string.h>
struct tftp_req {
ip_addr_t addr;
u16_t port;
u16_t opcode;
enum tftp_transfer_mode mode;
char* fname;
};
struct tftp_state {
const struct tftp_context *ctx;
void *handle;
@ -97,14 +105,33 @@ struct tftp_state {
};
static struct tftp_state tftp_state;
static struct tftp_req tftp_req;
static void tftp_tmr(void *arg);
static void tftp_req_tmr(void *arg);
static const char *mode_to_string(enum tftp_transfer_mode mode);
static void
clear_req(void)
{
ip_addr_set_any(0, &tftp_req.addr);
tftp_req.port = 0;
tftp_req.opcode = 0;
free(tftp_req.fname);
tftp_req.fname = NULL;
tftp_req.mode = 0;
sys_untimeout(tftp_req_tmr, NULL);
}
static void
close_handle(void)
{
clear_req();
tftp_state.port = 0;
ip_addr_set_any(0, &tftp_state.addr);
tftp_state.retries = 0;
if (tftp_state.last_data != NULL) {
pbuf_free(tftp_state.last_data);
@ -209,6 +236,12 @@ send_ack(const ip_addr_t *addr, u16_t port, u16_t blknum)
return ret;
}
static err_t
resend_request(void)
{
return send_request(&tftp_req.addr, tftp_req.port, tftp_req.opcode, tftp_req.fname, mode_to_string(tftp_req.mode));
}
static err_t
resend_data(const ip_addr_t *addr, u16_t port)
{
@ -336,6 +369,9 @@ tftp_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr
tftp_state.last_pkt = tftp_state.timer;
tftp_state.retries = 0;
if (tftp_req.fname)
clear_req();
switch (opcode) {
case PP_HTONS(TFTP_RRQ): /* fall through */
case PP_HTONS(TFTP_WRQ): {
@ -542,6 +578,26 @@ tftp_tmr(void *arg)
}
}
static void
tftp_req_tmr(void *arg)
{
if (tftp_state.handle == NULL) {
return;
}
sys_timeout(TFTP_TIMER_MSECS, tftp_req_tmr, NULL);
if (tftp_state.retries < TFTP_MAX_RETRIES) {
LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: req timeout, retrying\n"));
resend_request();
tftp_state.retries++;
} else {
LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: req timeout\n"));
tftp_state.ctx->error(tftp_state.handle, -1, "Request timeout", strlen("Request timeout"));
close_handle();
}
}
/**
* Initialize TFTP client/server.
* @param mode TFTP mode (client/server)
@ -637,6 +693,20 @@ mode_to_string(enum tftp_transfer_mode mode)
return NULL;
}
err_t
start_send_requests(const ip_addr_t *addr, u16_t port, u16_t opcode, const char* fname, enum tftp_transfer_mode mode)
{
tftp_req.addr = *addr;
tftp_req.port = port;
tftp_req.opcode = opcode;
tftp_req.fname = strdup(fname);
tftp_req.mode = mode;
if (!tftp_req.fname)
return ERR_MEM;
sys_timeout(TFTP_TIMER_MSECS, tftp_req_tmr, NULL);
return resend_request();
}
err_t
tftp_get(void* handle, const ip_addr_t *addr, u16_t port, const char* fname, enum tftp_transfer_mode mode)
{
@ -647,7 +717,7 @@ tftp_get(void* handle, const ip_addr_t *addr, u16_t port, const char* fname, enu
tftp_state.handle = handle;
tftp_state.blknum = 1;
tftp_state.mode_write = 1; /* We want to receive data */
return send_request(addr, port, TFTP_RRQ, fname, mode_to_string(mode));
return start_send_requests(addr, port, TFTP_RRQ, fname, mode);
}
err_t
@ -660,7 +730,7 @@ tftp_put(void* handle, const ip_addr_t *addr, u16_t port, const char* fname, enu
tftp_state.handle = handle;
tftp_state.blknum = 1;
tftp_state.mode_write = 0; /* We want to send data */
return send_request(addr, port, TFTP_WRQ, fname, mode_to_string(mode));
return start_send_requests(addr, port, TFTP_WRQ, fname, mode);
}
#endif /* LWIP_UDP */