Fix segmentation fault caused by incorrectly accessing the cyclic timestamp buffer

packet-exchange/src/send_packet.c

@@ -37,6 +37,8 @@
 #include "common.h"
 #include "send_packet.h"
 
+#define TIMESTAMP_BUFFER_SIZE 64
+
 static void *poll_thread(void *p);
 static void process_error_queue();
 
@@ -56,7 +58,7 @@ static struct sock_txtime sk_txtime;
 static char *tx_buffer;
 static int sock_fd;
 
-static uint64_t timestamps_buffer[64];
+static uint64_t timestamps_buffer[TIMESTAMP_BUFFER_SIZE];
 static int ts_buf_read_index = 0;
 static int ts_buf_write_index = 0;
 
@@ -129,7 +131,7 @@ void send_udp_packet(char *data,
 
   if (params->use_timestamps) {
     clock_gettime(CLOCK_REALTIME, &ts);
-    timestamps_buffer[ts_buf_write_index++] = ts_to_uint(ts);
+    timestamps_buffer[(ts_buf_write_index++) % TIMESTAMP_BUFFER_SIZE] = ts_to_uint(ts);
   }
 
   packets_sent++;
@@ -220,7 +222,7 @@ static void process_error_queue() {
 
       struct timespec *stamp = (struct timespec *)CMSG_DATA(cmsg);
 
-      int kernel_latency = (ts_to_uint(*stamp) - timestamps_buffer[ts_buf_read_index++]) / 1000;
+      int kernel_latency = (ts_to_uint(*stamp) - timestamps_buffer[(ts_buf_read_index++) % TIMESTAMP_BUFFER_SIZE]) / 1000;
 
       stats->min_kernel_latency = min(kernel_latency, stats->min_kernel_latency);
       stats->max_kernel_latency = max(kernel_latency, stats->max_kernel_latency);