This patchset moves the forwarding of frames in mac80211 hwsim into user-space. This gives the ability to simulate loss, retransmission delays, collisions, etc. in a controlled environment while still using the whole stack. A few disclaimers: - We don't expire pending (transmitted but not status-reported) packets. This is a nice DoS waiting to happen, so that needs to be fixed. - This breaks the in-kernel forwarding. It may be useful to still do that for quick-and-dirty testing, via modparam or something. - It really wants a configuration ioctl that happens before the device is registered, so you can set up the rate set and so forth. The ABI needs work in general. How to use: 1. Write a program to open /dev/mac80211_hwsim_control for as many radios as you want, and shuffle packets between the file descriptors. Or suitably modify my proof-of-concept: http://bobcopeland.com/srcs/wifi_sim.tar.gz 2. Set up network namespaces, and put the devices in separate namespaces. This may no longer be necessary, I haven't kept up. 3. Run hostapd on one interface and connect to it from the other(s). I keep this patch to unbreak netns, which will likely explode your computer: --- net/core/dev.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index bcc490c..2306aec 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5628,6 +5628,7 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char if (dev->features & NETIF_F_NETNS_LOCAL) goto out; +#if 0 #ifdef CONFIG_SYSFS /* Don't allow real devices to be moved when sysfs * is enabled. @@ -5636,6 +5637,7 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char if (dev->dev.parent) goto out; #endif +#endif /* Ensure the device has been registrered */ err = -EINVAL; -- 1.6.3.3 Here's the set of scripts I use to set up namespaces and run hostapd and iperf. (run.sh is just a wrapper around hostapd with the right config file etc.) connect.sh: ~~~~~~~~~~~ #! /bin/sh ifconfig wlan1 up iw dev wlan1 connect -w test 5180 ifconfig wlan1 192.168.10.2 # end connect.sh start_sim.pl ~~~~~~~~~~~~ #! /usr/bin/perl # Launch simulation program in different netns. # You probably have to manually run connect.sh due to timing # and my Expect lameness. use Expect; my $args = join(" ", @ARGV); my $exp = Expect->spawn("screen") or die "Couldn't start screen"; my $timeout = 3; my $ctrla = chr(1); my $sim = "./sim"; $exp->expect($timeout, [qr/\[Press Space for next page; Return to end.]/ => sub { my $exp = shift; # start screen $exp->send("\n"); wait_prompt($exp); # load mac80211_hwsim $exp->send("modprobe mac80211_hwsim\n"); wait_prompt($exp); # create a second window $exp->send("${ctrla}c"); wait_prompt($exp); # start simulator here $exp->send("$sim $args | tee sim.log\n"); # create a third window $exp->send("${ctrla}c"); # start netns in this window $exp->send("./ns_exec -c -n /bin/bash\n"); exp_continue; }], [qr/Parent waiting for pid (\d+)/ => sub { my $exp = shift; my $pid = ($exp->matchlist)[0] . "\n"; my $phy = `iw dev | head -1`; chomp $phy; $phy =~ s/.*(phy\d+).*/\1/g; print "pid: " . ($exp->matchlist)[0] . ", phy: $phy\n"; # create loopback $exp->send("ip link set lo up\n"); wait_prompt($exp); # start hostapd in background $exp->send("cd hostap/hostapd\n"); wait_prompt($exp); $exp->send("iw reg set US\n"); wait_prompt($exp); # go to window 0 and move the device to the other ns $exp->send("${ctrla}0"); $exp->send("iw $phy set netns $pid\n"); wait_prompt($exp); # go back to window 2 and start hostapd in background $exp->send("${ctrla}2"); $exp->send("./run.sh >hostapd.log 2>&1 &\n"); wait_prompt($exp); # start iperf in background $exp->send("iperf -s &\n"); wait_prompt($exp); # go back to window 0 and get ready to do something $exp->send("${ctrla}0"); wait_prompt($exp); sleep(1); $exp->send("./connect.sh\n"); $exp->interact; }] ); sub wait_prompt { my $exp = shift; $exp->expect($timeout, '#'); } Bob Copeland (3): mac80211_hwsim: extract radio creation code mac80211_hwsim: add a control device mac80211_hwsim: enable user space frame processing drivers/net/wireless/mac80211_hwsim.c | 899 ++++++++++++++++++++------------- drivers/net/wireless/mac80211_hwsim.h | 42 ++ 2 files changed, 594 insertions(+), 347 deletions(-) create mode 100644 drivers/net/wireless/mac80211_hwsim.h -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
