The TFTP protocol uses a default block size of 512 bytes. This value is sub-optimal for ethernet devices, which have a MTU (Maximum Transmission Unit) of 1500 bytes. When taking into acount the overhead of the IP and UDP layers, this leaves 1468 bytes for the TFTP payload.
This patch introduces a new function: tftp_client_set_blksize() which may be used to change the block size from the default. It has to be called after tftp_client_init() and before tftp_get(). If the server does not support the option, the client will still accept to receive 512-byte blocks.
Signed-off-by: Jerome Forissier jerome.forissier@linaro.org --- lib/lwip/lwip/src/apps/tftp/tftp.c | 94 +++++++++++++++++-- .../lwip/src/include/lwip/apps/tftp_client.h | 1 + 2 files changed, 89 insertions(+), 6 deletions(-)
diff --git a/lib/lwip/lwip/src/apps/tftp/tftp.c b/lib/lwip/lwip/src/apps/tftp/tftp.c index ddfdbfc0c1b..e08e9665124 100644 --- a/lib/lwip/lwip/src/apps/tftp/tftp.c +++ b/lib/lwip/lwip/src/apps/tftp/tftp.c @@ -57,7 +57,7 @@ #include "lwip/timeouts.h" #include "lwip/debug.h"
-#define TFTP_MAX_PAYLOAD_SIZE 512 +#define TFTP_DEFAULT_BLOCK_SIZE 512 #define TFTP_HEADER_LENGTH 4
#define TFTP_RRQ 1 @@ -65,6 +65,7 @@ #define TFTP_DATA 3 #define TFTP_ACK 4 #define TFTP_ERROR 5 +#define TFTP_OACK 6
enum tftp_error { TFTP_ERROR_FILE_NOT_FOUND = 1, @@ -88,9 +89,11 @@ struct tftp_state { int timer; int last_pkt; u16_t blknum; + u16_t blksize; u8_t retries; u8_t mode_write; u8_t tftp_mode; + bool wait_oack; };
static struct tftp_state tftp_state; @@ -137,10 +140,24 @@ send_request(const ip_addr_t *addr, u16_t port, u16_t opcode, const char* fname, { size_t fname_length = strlen(fname)+1; size_t mode_length = strlen(mode)+1; - struct pbuf* p = init_packet(opcode, 0, fname_length + mode_length - 2); + size_t blksize_length = 0; + struct pbuf* p; char* payload; err_t ret;
+ if (tftp_state.blksize) { + blksize_length = 14; /* maximum (blksize is a u16_t): 'blksize\0XXXXX\0' */ + if (tftp_state.blksize < 10000) + blksize_length--; + if (tftp_state.blksize < 1000) + blksize_length--; + if (tftp_state.blksize < 100) + blksize_length--; + if (tftp_state.blksize < 10) + blksize_length--; + } + + p = init_packet(opcode, 0, fname_length + mode_length + blksize_length - 2); if (p == NULL) { return ERR_MEM; } @@ -148,7 +165,10 @@ send_request(const ip_addr_t *addr, u16_t port, u16_t opcode, const char* fname, payload = (char*) p->payload; MEMCPY(payload+2, fname, fname_length); MEMCPY(payload+2+fname_length, mode, mode_length); + if (tftp_state.blksize) + sprintf(payload+2+fname_length+mode_length, "blksize%c%d%c", 0, tftp_state.blksize, 0);
+ tftp_state.wait_oack = true; ret = udp_sendto(tftp_state.upcb, p, addr, port); pbuf_free(p); return ret; @@ -221,14 +241,14 @@ send_data(const ip_addr_t *addr, u16_t port) pbuf_free(tftp_state.last_data); }
- tftp_state.last_data = init_packet(TFTP_DATA, tftp_state.blknum, TFTP_MAX_PAYLOAD_SIZE); + tftp_state.last_data = init_packet(TFTP_DATA, tftp_state.blknum, TFTP_DEFAULT_BLOCK_SIZE); if (tftp_state.last_data == NULL) { return; }
payload = (u16_t *) tftp_state.last_data->payload;
- ret = tftp_state.ctx->read(tftp_state.handle, &payload[2], TFTP_MAX_PAYLOAD_SIZE); + ret = tftp_state.ctx->read(tftp_state.handle, &payload[2], TFTP_DEFAULT_BLOCK_SIZE); if (ret < 0) { send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Error occurred while reading the file."); close_handle(); @@ -239,6 +259,28 @@ send_data(const ip_addr_t *addr, u16_t port) resend_data(addr, port); }
+static u16_t payload_size(void) +{ + if (tftp_state.blksize) + return tftp_state.blksize; + return TFTP_DEFAULT_BLOCK_SIZE; +} + +static const char * +find_option(struct pbuf *p, const char *option) +{ + int i; + u16_t optlen = strlen(option); + const char *b = p->payload; + + for (i = 0; i + optlen + 1 < p->len; i++) { + if (lwip_strnstr(b + i, option, optlen)) + return b + i + optlen + 2; + } + + return NULL; +} + static void tftp_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr, u16_t port) { @@ -338,6 +380,15 @@ tftp_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr }
blknum = lwip_ntohs(sbuf[1]); + if (tftp_state.blksize && tftp_state.wait_oack) { + /* + * Data received while we are expecting an OACK for our blksize option. + * This means the server doesn't support it, let's switch back to the + * default block size. + */ + tftp_state.blksize = 0; + tftp_state.wait_oack = false; + } if (blknum == tftp_state.blknum) { pbuf_remove_header(p, TFTP_HEADER_LENGTH);
@@ -349,7 +400,7 @@ tftp_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr send_ack(addr, port, blknum); }
- if (p->tot_len < TFTP_MAX_PAYLOAD_SIZE) { + if (p->tot_len < payload_size()) { close_handle(); } else { tftp_state.blknum++; @@ -386,7 +437,7 @@ tftp_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr lastpkt = 0;
if (tftp_state.last_data != NULL) { - lastpkt = tftp_state.last_data->tot_len != (TFTP_MAX_PAYLOAD_SIZE + TFTP_HEADER_LENGTH); + lastpkt = tftp_state.last_data->tot_len != (TFTP_DEFAULT_BLOCK_SIZE + TFTP_HEADER_LENGTH); }
if (!lastpkt) { @@ -405,6 +456,25 @@ tftp_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr close_handle(); } break; + case PP_HTONS(TFTP_OACK): { + const char *optval = find_option(p, "blksize"); + u16_t srv_blksize = 0; + tftp_state.wait_oack = false; + if (optval) { + if (!tftp_state.blksize) { + /* We did not request this option */ + send_error(addr, port, TFTP_ERROR_ILLEGAL_OPERATION, "blksize unexpected"); + } + srv_blksize = atoi(optval); + if (srv_blksize <= 0 || srv_blksize > tftp_state.blksize) { + send_error(addr, port, TFTP_ERROR_ILLEGAL_OPERATION, "Invalid blksize"); + } + LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: accepting blksize=%d\n", srv_blksize)); + tftp_state.blksize = srv_blksize; + } + send_ack(addr, port, 0); + break; + } default: send_error(addr, port, TFTP_ERROR_ILLEGAL_OPERATION, "Unknown operation"); break; @@ -493,6 +563,18 @@ tftp_init_client(const struct tftp_context *ctx) return tftp_init_common(LWIP_TFTP_MODE_CLIENT, ctx); }
+/** @ingroup tftp + * Set the block size to be used by the TFTP client. The server may choose to + * accept a lower value. + * @param blksize Block size in bytes + */ +void +tftp_client_set_blksize(u16_t blksize) +{ + if (blksize != TFTP_DEFAULT_BLOCK_SIZE) + tftp_state.blksize = blksize; +} + /** @ingroup tftp * Deinitialize ("turn off") TFTP client/server. */ diff --git a/lib/lwip/lwip/src/include/lwip/apps/tftp_client.h b/lib/lwip/lwip/src/include/lwip/apps/tftp_client.h index 24dbda6a8c9..e1e21d06b67 100644 --- a/lib/lwip/lwip/src/include/lwip/apps/tftp_client.h +++ b/lib/lwip/lwip/src/include/lwip/apps/tftp_client.h @@ -44,6 +44,7 @@ enum tftp_transfer_mode { };
err_t tftp_init_client(const struct tftp_context* ctx); +void tftp_client_set_blksize(u16_t blksize); err_t tftp_get(void* handle, const ip_addr_t *addr, u16_t port, const char* fname, enum tftp_transfer_mode mode); err_t tftp_put(void* handle, const ip_addr_t *addr, u16_t port, const char* fname, enum tftp_transfer_mode mode);