httpd: trivial simplification

[oweals/busybox.git] / networking / tftp.c

diff --git a/networking/tftp.c b/networking/tftp.c
index 6be265b4cdd0ef7a29b5d90ff2a61580611ccc43..59f53ae4a735e026566667ac1e7fed221970268d 100644 (file)
--- a/networking/tftp.c
+++ b/networking/tftp.c
@@ -21,12 +21,12 @@
 
 #include "libbb.h"
 
-
 #if ENABLE_FEATURE_TFTP_GET || ENABLE_FEATURE_TFTP_PUT
 
-#define TFTP_BLOCKSIZE_DEFAULT 512     /* according to RFC 1350, don't change */
-#define TFTP_TIMEOUT 5 /* seconds */
-#define TFTP_NUM_RETRIES 5 /* number of retries */
+#define TFTP_BLOCKSIZE_DEFAULT 512      /* according to RFC 1350, don't change */
+#define TFTP_TIMEOUT_MS         50
+#define TFTP_MAXTIMEOUT_MS    2000
+#define TFTP_NUM_RETRIES        12      /* number of backed-off retries */
 
 /* opcodes we support */
 #define TFTP_RRQ   1
@@ -114,9 +114,8 @@ static int tftp( USE_GETPUT(const int cmd,)
                const char *remotefile, const int localfd,
                unsigned port, int tftp_bufsize)
 {
-       struct timeval tv;
-       fd_set rfds;
-       int socketfd;
+       struct pollfd pfd[1];
+#define socketfd (pfd[0].fd)
        int len;
        int send_len;
        USE_FEATURE_TFTP_BLOCKSIZE(smallint want_option_ack = 0;)
@@ -124,7 +123,7 @@ static int tftp( USE_GETPUT(const int cmd,)
        uint16_t opcode;
        uint16_t block_nr = 1;
        uint16_t recv_blk;
-       int timeout = TFTP_NUM_RETRIES;
+       int retries, waittime_ms;
        char *cp;
 
        unsigned org_port;
@@ -206,6 +205,10 @@ static int tftp( USE_GETPUT(const int cmd,)
                send_len = cp - xbuf;
                /* NB: send_len value is preserved in code below
                 * for potential resend */
+
+               retries = TFTP_NUM_RETRIES;     /* re-initialize */
+               waittime_ms = TFTP_TIMEOUT_MS;
+
  send_again:
 #if ENABLE_DEBUG_TFTP
                fprintf(stderr, "sending %u bytes\n", send_len);
@@ -218,14 +221,11 @@ static int tftp( USE_GETPUT(const int cmd,)
                if (finished && (opcode == TFTP_ACK))
                        goto ret;
 
-               timeout = TFTP_NUM_RETRIES;     /* re-initialize */
  recv_again:
                /* 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)) {
+               /*pfd[0].fd = socketfd;*/
+               pfd[0].events = POLLIN;
+               switch (safe_poll(pfd, 1, waittime_ms)) {
                        unsigned from_port;
                case 1:
                        from->len = peer_lsa->len;
@@ -248,15 +248,21 @@ static int tftp( USE_GETPUT(const int cmd,)
                                goto recv_again;
                        goto process_pkt;
                case 0:
-                       timeout--;
-                       if (timeout == 0) {
-                               bb_error_msg("last timeout");
+                       retries--;
+                       if (retries == 0) {
+                               bb_error_msg("timeout");
                                goto ret;
                        }
-                       bb_error_msg("last timeout" + 5);
+
+                       /* exponential backoff with limit */
+                       waittime_ms += waittime_ms/2;
+                       if (waittime_ms > TFTP_MAXTIMEOUT_MS) {
+                               waittime_ms = TFTP_MAXTIMEOUT_MS;
+                       }
+
                        goto send_again; /* resend last sent pkt */
                default:
-                       bb_perror_msg("select");
+                       /*bb_perror_msg("poll"); - done in safe_poll */
                        goto ret;
                }
  process_pkt: