Unused code?

[Meteor]

Hello,

recently, I am reading the dsvpn code to study network-related knowledge.

And i found that a part of code isn't used.

           if (2 + TAG_LEN + MAX_PACKET_LEN != len_with_header) {
                unsigned char *rbuf      = client_buf->len;
                size_t         remaining = client_buf->pos - len_with_header, i;
                for (i = 0; i < remaining; i++) {
                    rbuf[i] = rbuf[len_with_header + i];
                }
            }

I am confused.
What does the code use for?

[Frank Denis]

It's not unused. It handles the case where the input buffer is not completely full, shifting the bytes to the beginning of the buffer for the next read.