Make UDP tests honor the -w option for setting the socket buffer

size.

This appears to be necessary on some long, high-bandwidth paths
to get sane results, either by reducing packet loss or by somehow
allowing the sending host of a test to go faster.

Fixes #219.

3 files changed, 34 insertions, 2 deletions

diff --git a/src/iperf3.1 b/src/iperf3.1
index a9fe8e9..a7e67e6 100644
--- a/src/iperf3.1
+++ b/src/iperf3.1
@@ -124,7 +124,7 @@ number of parallel client streams to run
 run in reverse mode (server sends, client receives)
 .TP
 .BR -w ", " --window " \fIn\fR[KM]"
-TCP window size / socket buffer size (this gets sent to the server and used on that side too)
+window size / socket buffer size (this gets sent to the server and used on that side too)
 .TP
 .BR -M ", " --set-mss " \fIn\fR"
 set TCP maximum segment size (MTU - 40 bytes)
diff --git a/src/iperf_locale.c b/src/iperf_locale.c
index 91bacc4..354906f 100644
--- a/src/iperf_locale.c
+++ b/src/iperf_locale.c
@@ -132,7 +132,7 @@ const char usage_longstr[] = "Usage: iperf [-s|-c host] [options]\n"
                            "  --cport         <port>    bind to a specific client port (TCP and UDP, default: ephemeral port)\n"
                            "  -P, --parallel  #         number of parallel client streams to run\n"
                            "  -R, --reverse             run in reverse mode (server sends, client receives)\n"
-                           "  -w, --window    #[KMG]    TCP window size (socket buffer size)\n"
+                           "  -w, --window    #[KMG]    set window size / socket buffer size\n"
 #if defined(HAVE_TCP_CONGESTION)
                            "  -C, --congestion <algo>   set TCP congestion control algorithm (Linux and FreeBSD only)\n"
 #endif /* HAVE_TCP_CONGESTION */
diff --git a/src/iperf_udp.c b/src/iperf_udp.c
index 0f55226..8d32dbe 100644
--- a/src/iperf_udp.c
+++ b/src/iperf_udp.c
@@ -229,6 +229,22 @@ iperf_udp_accept(struct iperf_test *test)
     }
 
     /*
+     * Set socket buffer size if requested.  Do this for both sending and
+     * receiving so that we can cover both normal and --reverse operation.
+     */
+    int opt;
+    if ((opt = test->settings->socket_bufsize)) {
+        if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, &opt, sizeof(opt)) < 0) {
+            i_errno = IESETBUF;
+            return -1;
+        }
+        if (setsockopt(s, SOL_SOCKET, SO_SNDBUF, &opt, sizeof(opt)) < 0) {
+            i_errno = IESETBUF;
+            return -1;
+        }
+    }
+
+    /*
      * Create a new "listening" socket to replace the one we were using before.
      */
     test->prot_listener = netannounce(test->settings->domain, Pudp, test->bind_address, test->server_port);
@@ -292,6 +308,22 @@ iperf_udp_connect(struct iperf_test *test)
     }
 
     /*
+     * Set socket buffer size if requested.  Do this for both sending and
+     * receiving so that we can cover both normal and --reverse operation.
+     */
+    int opt;
+    if ((opt = test->settings->socket_bufsize)) {
+        if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, &opt, sizeof(opt)) < 0) {
+            i_errno = IESETBUF;
+            return -1;
+        }
+        if (setsockopt(s, SOL_SOCKET, SO_SNDBUF, &opt, sizeof(opt)) < 0) {
+            i_errno = IESETBUF;
+            return -1;
+        }
+    }
+
+    /*
      * Write a datagram to the UDP stream to let the server know we're here.
      * The server learns our address by obtaining its peer's address.
      */