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authorMark McLoughlin <markmc@redhat.com>2009-10-22 17:49:13 +0100
committerAnthony Liguori <aliguori@us.ibm.com>2009-10-30 08:39:28 -0500
commit15ac913bfe10abe142334a8b432c1f4c410fb04b (patch)
treea273c3b9b4f6cf5671c6e2980337b9feae979058 /net/tap-linux.c
parentc28b1c1007883baea05bff4bc7b20d354c4b47a1 (diff)
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net: move tap_set_sndbuf() to tap-linux.c
TUNSETSNDBUF is only available on linux Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'net/tap-linux.c')
-rw-r--r--net/tap-linux.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/net/tap-linux.c b/net/tap-linux.c
index c6f751e..6c3b6e3 100644
--- a/net/tap-linux.c
+++ b/net/tap-linux.c
@@ -76,3 +76,26 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required
fcntl(fd, F_SETFL, O_NONBLOCK);
return fd;
}
+
+/* sndbuf should be set to a value lower than the tx queue
+ * capacity of any destination network interface.
+ * Ethernet NICs generally have txqueuelen=1000, so 1Mb is
+ * a good default, given a 1500 byte MTU.
+ */
+#define TAP_DEFAULT_SNDBUF 1024*1024
+
+int tap_set_sndbuf(int fd, QemuOpts *opts)
+{
+ int sndbuf;
+
+ sndbuf = qemu_opt_get_size(opts, "sndbuf", TAP_DEFAULT_SNDBUF);
+ if (!sndbuf) {
+ sndbuf = INT_MAX;
+ }
+
+ if (ioctl(fd, TUNSETSNDBUF, &sndbuf) == -1 && qemu_opt_get(opts, "sndbuf")) {
+ qemu_error("TUNSETSNDBUF ioctl failed: %s\n", strerror(errno));
+ return -1;
+ }
+ return 0;
+}