Bug #779 - honour overflow for all pps values

I'm not sure why PPS overflow protection was not implemented for lower rates.
This fix makes the overflow protection always available.

Also fix a compile warning.

docs/CHANGELOG

@@ -1,4 +1,5 @@
 09/03/2023 Version 4.5.0-beta1
+    - low PPS values run at full speed after several days (#779)
     - create DLT_LINUX_SLL2 plugin (#727)
 
 06/04/2023 Version 4.4.4

src/common/sendpacket.c

@@ -1066,7 +1066,7 @@ sendpacket_open_bpf(const char *device, char *errbuf)
 {
     sendpacket_t *sp;
     char bpf_dev[16];
-    int dev, mysocket, link_offset, link_type;
+    int dev, mysocket;
     struct ifreq ifr;
     struct bpf_version bv;
     u_int v;
@@ -1134,43 +1134,10 @@ sendpacket_open_bpf(const char *device, char *errbuf)
     }
 #endif
 
-    /* assign link type and offset */
-    switch (v) {
-    case DLT_SLIP:
-        link_offset = 0x10;
-        break;
-    case DLT_RAW:
-        link_offset = 0x0;
-        break;
-    case DLT_PPP:
-        link_offset = 0x04;
-        break;
-    case DLT_EN10MB:
-    default: /* default to Ethernet */
-        link_offset = 0xe;
-        break;
-    }
-#if _BSDI_VERSION - 0 > 199510
-    switch (v) {
-    case DLT_SLIP:
-        v = DLT_SLIP_BSDOS;
-        link_offset = 0x10;
-        break;
-    case DLT_PPP:
-        v = DLT_PPP_BSDOS;
-        link_offset = 0x04;
-        break;
-    }
-#endif
-
-    link_type = v;
-
     /* allocate our sp handle, and return it */
     sp = (sendpacket_t *)safe_malloc(sizeof(sendpacket_t));
     strlcpy(sp->device, device, sizeof(sp->device));
     sp->handle.fd = mysocket;
-    // sp->link_type = link_type;
-    // sp->link_offset = link_offset;
     sp->handle_type = SP_TYPE_BPF;
 
     return sp;

src/send_packets.c

@@ -1025,7 +1025,7 @@ calc_sleep_time(tcpreplay_t *ctx,
              *
              * ensure there is no overflow in cases where bits_sent is very high
              */
-            if (bits_sent > COUNTER_OVERFLOW_RISK && bps > 500000)
+            if (bits_sent > COUNTER_OVERFLOW_RISK)
                 next_tx_us = (bits_sent * 1000) / bps * 1000;
             else
                 next_tx_us = (bits_sent * 1000000) / bps;