fix: incorrect progress percentage calculation

Correct the wrong progress percentage calculation. This was visible
especially when the blocksize was (much) larger than the actual file
size, resulting in values greater than 100%.

tftpd.hpp

@@ -327,8 +327,9 @@ class receiver : public server
             if (dp_->th_opcode == DATA) {
                 // NOLINTNEXTLINE(cppcoreguidelines-pro-type-union-access)
                 if (dp_->th_block == block) {
-                    if (g_tsize != 0) { // NOTE: prevent division by zero! CK
-                        size_t const percent = 100UL * (block * g_segsize) / g_tsize;
+                    if (g_tsize != 0 && g_segsize != 0) { // NOTE: prevent division by zero! CK
+                        auto totalBlocks = g_tsize / g_segsize + (g_tsize % g_segsize) > 0 ? 1 : 0;
+                        size_t const percent = (100UL * block) / totalBlocks;
                         if (percent != percent_) {
                             syslog(LOG_NOTICE, "tftpd: Progress: %lu%% received\n", percent);
                             percent_ = percent;