Simulate packet reordering.

With a configurable chance, delay a packet for a random amount of packets.

diff --git a/test.c b/test.c
index 1df172efa56556443bfa5c6ec913f9e9014b0035..d7e1cdc5788db3dc8638e3fba93ecd09a292fb0b 100644 (file)
--- a/test.c
+++ b/test.c
@@ -24,11 +24,16 @@ long inpktno;
 long outpktno;
 long dropfrom;
 long dropto;
+double reorder;
+long reorder_dist;
 double dropin;
 double dropout;
 long total_out;
 long total_in;
 
+char *reorder_data;
+size_t reorder_len;
+int reorder_countdown;
 
 void debug(const char *format, ...) {
        struct timeval now;
@@ -63,8 +68,26 @@ void do_accept(struct utcp_connection *nc, uint16_t port) {
 ssize_t do_send(struct utcp *utcp, const void *data, size_t len) {
        int s = *(int *)utcp->priv;
        outpktno++;
-       if(outpktno < dropto && outpktno >= dropfrom && drand48() < dropout)
-               return len;
+       if(outpktno >= dropfrom && outpktno < dropto) {
+               if(drand48() < dropout)
+                       return len;
+               if(!reorder_data && drand48() < reorder) {
+                       reorder_data = malloc(len);
+                       reorder_len = len;
+                       memcpy(reorder_data, data, len);
+                       reorder_countdown = 1 + drand48() * reorder_dist;
+                       return len;
+               }
+       }
+
+       if(reorder_data) {
+               if(--reorder_countdown < 0) {
+                       total_out += reorder_len;
+                       send(s, reorder_data, reorder_len, MSG_DONTWAIT);
+                       free(reorder_data);
+                       reorder_data = NULL;
+               }
+       }
 
        total_out += len;
        ssize_t result = send(s, data, len, MSG_DONTWAIT);
@@ -87,6 +110,8 @@ int main(int argc, char *argv[]) {
        dropout = atof(getenv("DROPOUT") ?: "0");
        dropfrom = atoi(getenv("DROPFROM") ?: "0");
        dropto = atoi(getenv("DROPTO") ?: "0");
+       reorder = atof(getenv("REORDER") ?: "0");
+       reorder_dist = atoi(getenv("REORDER_DIST") ?: "10");
 
        struct addrinfo *ai;
        struct addrinfo hint = {
@@ -190,6 +215,7 @@ int main(int argc, char *argv[]) {
 
        utcp_close(c);
        utcp_exit(u);
+       free(reorder_data);
 
        debug("Total bytes in: %ld, out: %ld\n", total_in, total_out);