(a) command line flag to repeat sending pcap, (b) command line flags to set sleep delay in nanoseconds every frequency packets, (c) command line option to group packets into bigger packets, (d) show sends stats per second

Author: simonhf

udpreplay.cpp

@@ -28,6 +28,8 @@ SOFTWARE.
 #include <netinet/udp.h>
 #include <pcap/pcap.h>
 #include <unistd.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
 
 int main(int argc, char *argv[]) {
   static const char usage[] =
@@ -36,15 +38,23 @@ int main(int argc, char *argv[]) {
       "  -i iface    interface to send packets through\n"
       "  -l          enable loopback\n"
       "  -s speed    replay speed relative to pcap timestamps\n"
+      "  -d delay    usec; e.g. 1,000 is 1 ms\n"
+      "  -f freq     delay every <freq> packets sent\n"
+      "  -g group    group <group> packets together, e.g. 1 or 6\n"
+      "  -r          repeat at end of pcap file\n"
       "  -t ttl      packet ttl";
 
   int ifindex = 0;
   int loopback = 0;
-  double speed = 1;
+  //double speed = 1;
   int ttl = -1;
+  int delay  = 100; // 0.1 ms
+  int freq   =  50; // delay every 50 packets
+  int repeat =   0;
+  int group  =   1;
 
   int opt;
-  while ((opt = getopt(argc, argv, "i:ls:t:")) != -1) {
+  while ((opt = getopt(argc, argv, "i:ls:t:rd:f:g:")) != -1) {
     switch (opt) {
     case 'i':
       ifindex = if_nametoindex(optarg);
@@ -56,8 +66,20 @@ int main(int argc, char *argv[]) {
     case 'l':
       loopback = 1;
       break;
-    case 's':
-      speed = std::stod(optarg);
+    case 'r':
+      repeat = 1;
+      break;
+    //case 's':
+    //  speed = std::stod(optarg);
+    //  break;
+    case 'd':
+      delay = std::stoi(optarg);
+      break;
+    case 'f':
+      freq = std::stoi(optarg);
+      break;
+    case 'g':
+      group = std::stoi(optarg);
       break;
     case 't':
       ttl = std::stoi(optarg);
@@ -104,6 +126,9 @@ int main(int argc, char *argv[]) {
     }
   }
 
+  time_t last_time = time(NULL);
+  REPEAT:;
+
   char errbuf[PCAP_ERRBUF_SIZE];
   pcap_t *handle = pcap_open_offline(argv[optind], errbuf);
   if (handle == nullptr) {
@@ -114,7 +139,17 @@ int main(int argc, char *argv[]) {
   pcap_pkthdr header;
   const u_char *p;
   timeval tv = {0, 0};
+  unsigned long count = 0;
+  unsigned long sent  = 0;
+  unsigned long last_count = 0;
+  unsigned long last_sent  = 0;
+#define JUMBO_MAX_BYTES (9001)
+  char jumbo[JUMBO_MAX_BYTES];
+  int  jumbo_appends = 0;
+  int  jumbo_used    = 0;
+  printf("- starting sending loop\n");
   while ((p = pcap_next(handle, &header))) {
+    p += 2; // see https://www.eecis.udel.edu/~sunshine/expcs/code/pcap_packet_read.c
     if (header.len != header.caplen) {
       continue;
     }
@@ -137,23 +172,41 @@ int main(int argc, char *argv[]) {
     }
     timeval diff;
     timersub(&header.ts, &tv, &diff);
-    usleep((diff.tv_sec * 1000000 + diff.tv_usec) * speed);
+    //do not use original timings usleep((diff.tv_sec * 1000000 + diff.tv_usec) * speed);
 
     ssize_t len = ntohs(udp->len) - 8;
     const u_char *d = &p[sizeof(ether_header) + ip->ihl * 4 + sizeof(udphdr)];
 
+    if(jumbo_used + len > JUMBO_MAX_BYTES){ printf("ERROR: jumbo overflow detected!\n"); exit(0); }
+    memcpy(&jumbo[jumbo_used], d, len);
+    jumbo_appends ++;
+    jumbo_used    += len;
+    if(jumbo_appends == group) { // 6 for MTU 9,001 byte packet
+
     sockaddr_in addr;
     memset(&addr, 0, sizeof(addr));
     addr.sin_family = AF_INET;
     addr.sin_port = udp->dest;
-    addr.sin_addr = {ip->daddr};
-    auto n = sendto(fd, d, len, 0, reinterpret_cast<sockaddr *>(&addr),
+    //addr.sin_addr = {ip->daddr};
+    addr.sin_addr.s_addr = inet_addr("10.130.18.8"); // force send packets to this IP!
+    auto n = sendto(fd, &jumbo[0], jumbo_used, 0, reinterpret_cast<sockaddr *>(&addr),
                     sizeof(addr));
-    if (n != len) {
+    if (n != jumbo_used) {
       std::cerr << "sendto: " << strerror(errno) << std::endl;
       return 1;
     }
+    sent += jumbo_used;
+    if ((++ count % 100) == 0) { time_t this_time = time(NULL); if(this_time != last_time) { last_time = this_time; printf("- sent %lu bytes in %lu packets\n", sent - last_sent, count - last_count); last_sent = sent; last_count = count; }}
+    if ((count % freq) == 0) { usleep(delay); } // delay=100 means sleep for 0.1 ms
+    //if (count == 152) { exit(0); }
+
+    jumbo_appends = 0;
+    jumbo_used    = 0;
+    }
   }
+  printf("- sent %lu bytes in %lu packets total\n", sent, count);
+
+  if (repeat) { pcap_close(handle); goto REPEAT; }
 
   return 0;
 }