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-rw-r--r--drivers/net/loopback.c76
-rw-r--r--include/linux/netdevice.h2
-rw-r--r--lib/Kconfig.debug9
-rw-r--r--lib/Makefile1
-rw-r--r--lib/test_blackhole_dev.c100
-rw-r--r--net/core/dst.c2
-rw-r--r--net/ipv4/route.c3
-rw-r--r--net/ipv6/route.c2
-rw-r--r--tools/testing/selftests/net/Makefile2
-rw-r--r--tools/testing/selftests/net/config1
-rwxr-xr-xtools/testing/selftests/net/test_blackhole_dev.sh11
11 files changed, 195 insertions, 14 deletions
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index 87d361666cdd..3b39def5471e 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -55,6 +55,13 @@
#include <net/net_namespace.h>
#include <linux/u64_stats_sync.h>
+/* blackhole_netdev - a device used for dsts that are marked expired!
+ * This is global device (instead of per-net-ns) since it's not needed
+ * to be per-ns and gets initialized at boot time.
+ */
+struct net_device *blackhole_netdev;
+EXPORT_SYMBOL(blackhole_netdev);
+
/* The higher levels take care of making this non-reentrant (it's
* called with bh's disabled).
*/
@@ -150,12 +157,14 @@ static const struct net_device_ops loopback_ops = {
.ndo_set_mac_address = eth_mac_addr,
};
-/* The loopback device is special. There is only one instance
- * per network namespace.
- */
-static void loopback_setup(struct net_device *dev)
+static void gen_lo_setup(struct net_device *dev,
+ unsigned int mtu,
+ const struct ethtool_ops *eth_ops,
+ const struct header_ops *hdr_ops,
+ const struct net_device_ops *dev_ops,
+ void (*dev_destructor)(struct net_device *dev))
{
- dev->mtu = 64 * 1024;
+ dev->mtu = mtu;
dev->hard_header_len = ETH_HLEN; /* 14 */
dev->min_header_len = ETH_HLEN; /* 14 */
dev->addr_len = ETH_ALEN; /* 6 */
@@ -174,11 +183,20 @@ static void loopback_setup(struct net_device *dev)
| NETIF_F_NETNS_LOCAL
| NETIF_F_VLAN_CHALLENGED
| NETIF_F_LOOPBACK;
- dev->ethtool_ops = &loopback_ethtool_ops;
- dev->header_ops = &eth_header_ops;
- dev->netdev_ops = &loopback_ops;
+ dev->ethtool_ops = eth_ops;
+ dev->header_ops = hdr_ops;
+ dev->netdev_ops = dev_ops;
dev->needs_free_netdev = true;
- dev->priv_destructor = loopback_dev_free;
+ dev->priv_destructor = dev_destructor;
+}
+
+/* The loopback device is special. There is only one instance
+ * per network namespace.
+ */
+static void loopback_setup(struct net_device *dev)
+{
+ gen_lo_setup(dev, (64 * 1024), &loopback_ethtool_ops, &eth_header_ops,
+ &loopback_ops, loopback_dev_free);
}
/* Setup and register the loopback device. */
@@ -213,3 +231,43 @@ out:
struct pernet_operations __net_initdata loopback_net_ops = {
.init = loopback_net_init,
};
+
+/* blackhole netdevice */
+static netdev_tx_t blackhole_netdev_xmit(struct sk_buff *skb,
+ struct net_device *dev)
+{
+ kfree_skb(skb);
+ net_warn_ratelimited("%s(): Dropping skb.\n", __func__);
+ return NETDEV_TX_OK;
+}
+
+static const struct net_device_ops blackhole_netdev_ops = {
+ .ndo_start_xmit = blackhole_netdev_xmit,
+};
+
+/* This is a dst-dummy device used specifically for invalidated
+ * DSTs and unlike loopback, this is not per-ns.
+ */
+static void blackhole_netdev_setup(struct net_device *dev)
+{
+ gen_lo_setup(dev, ETH_MIN_MTU, NULL, NULL, &blackhole_netdev_ops, NULL);
+}
+
+/* Setup and register the blackhole_netdev. */
+static int __init blackhole_netdev_init(void)
+{
+ blackhole_netdev = alloc_netdev(0, "blackhole_dev", NET_NAME_UNKNOWN,
+ blackhole_netdev_setup);
+ if (!blackhole_netdev)
+ return -ENOMEM;
+
+ dev_init_scheduler(blackhole_netdev);
+ dev_activate(blackhole_netdev);
+
+ blackhole_netdev->flags |= IFF_UP | IFF_RUNNING;
+ dev_net_set(blackhole_netdev, &init_net);
+
+ return 0;
+}
+
+device_initcall(blackhole_netdev_init);
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index eeacebd7debb..88292953aa6f 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4870,4 +4870,6 @@ do { \
#define PTYPE_HASH_SIZE (16)
#define PTYPE_HASH_MASK (PTYPE_HASH_SIZE - 1)
+extern struct net_device *blackhole_netdev;
+
#endif /* _LINUX_NETDEVICE_H */
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index cbdfae379896..99272b5dd980 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1909,6 +1909,15 @@ config TEST_BPF
If unsure, say N.
+config TEST_BLACKHOLE_DEV
+ tristate "Test blackhole netdev functionality"
+ depends on m && NET
+ help
+ This builds the "test_blackhole_dev" module that validates the
+ data path through this blackhole netdev.
+
+ If unsure, say N.
+
config FIND_BIT_BENCHMARK
tristate "Test find_bit functions"
help
diff --git a/lib/Makefile b/lib/Makefile
index dcb558c7554d..6ac44fe2a37f 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -91,6 +91,7 @@ obj-$(CONFIG_TEST_DEBUG_VIRTUAL) += test_debug_virtual.o
obj-$(CONFIG_TEST_MEMCAT_P) += test_memcat_p.o
obj-$(CONFIG_TEST_OBJAGG) += test_objagg.o
obj-$(CONFIG_TEST_STACKINIT) += test_stackinit.o
+obj-$(CONFIG_TEST_BLACKHOLE_DEV) += test_blackhole_dev.o
obj-$(CONFIG_TEST_LIVEPATCH) += livepatch/
diff --git a/lib/test_blackhole_dev.c b/lib/test_blackhole_dev.c
new file mode 100644
index 000000000000..4c40580a99a3
--- /dev/null
+++ b/lib/test_blackhole_dev.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This module tests the blackhole_dev that is created during the
+ * net subsystem initialization. The test this module performs is
+ * by injecting an skb into the stack with skb->dev as the
+ * blackhole_dev and expects kernel to behave in a sane manner
+ * (in other words, *not crash*)!
+ *
+ * Copyright (c) 2018, Mahesh Bandewar <maheshb@google.com>
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/udp.h>
+#include <linux/ipv6.h>
+
+#include <net/dst.h>
+
+#define SKB_SIZE 256
+#define HEAD_SIZE (14+40+8) /* Ether + IPv6 + UDP */
+#define TAIL_SIZE 32 /* random tail-room */
+
+#define UDP_PORT 1234
+
+static int __init test_blackholedev_init(void)
+{
+ struct ipv6hdr *ip6h;
+ struct sk_buff *skb;
+ struct ethhdr *ethh;
+ struct udphdr *uh;
+ int data_len;
+ int ret;
+
+ skb = alloc_skb(SKB_SIZE, GFP_KERNEL);
+ if (!skb)
+ return -ENOMEM;
+
+ /* Reserve head-room for the headers */
+ skb_reserve(skb, HEAD_SIZE);
+
+ /* Add data to the skb */
+ data_len = SKB_SIZE - (HEAD_SIZE + TAIL_SIZE);
+ memset(__skb_put(skb, data_len), 0xf, data_len);
+
+ /* Add protocol data */
+ /* (Transport) UDP */
+ uh = (struct udphdr *)skb_push(skb, sizeof(struct udphdr));
+ skb_set_transport_header(skb, 0);
+ uh->source = uh->dest = htons(UDP_PORT);
+ uh->len = htons(data_len);
+ uh->check = 0;
+ /* (Network) IPv6 */
+ ip6h = (struct ipv6hdr *)skb_push(skb, sizeof(struct ipv6hdr));
+ skb_set_network_header(skb, 0);
+ ip6h->hop_limit = 32;
+ ip6h->payload_len = data_len + sizeof(struct udphdr);
+ ip6h->nexthdr = IPPROTO_UDP;
+ ip6h->saddr = in6addr_loopback;
+ ip6h->daddr = in6addr_loopback;
+ /* Ether */
+ ethh = (struct ethhdr *)skb_push(skb, sizeof(struct ethhdr));
+ skb_set_mac_header(skb, 0);
+
+ skb->protocol = htons(ETH_P_IPV6);
+ skb->pkt_type = PACKET_HOST;
+ skb->dev = blackhole_netdev;
+
+ /* Now attempt to send the packet */
+ ret = dev_queue_xmit(skb);
+
+ switch (ret) {
+ case NET_XMIT_SUCCESS:
+ pr_warn("dev_queue_xmit() returned NET_XMIT_SUCCESS\n");
+ break;
+ case NET_XMIT_DROP:
+ pr_warn("dev_queue_xmit() returned NET_XMIT_DROP\n");
+ break;
+ case NET_XMIT_CN:
+ pr_warn("dev_queue_xmit() returned NET_XMIT_CN\n");
+ break;
+ default:
+ pr_err("dev_queue_xmit() returned UNKNOWN(%d)\n", ret);
+ }
+
+ return 0;
+}
+
+static void __exit test_blackholedev_exit(void)
+{
+ pr_warn("test_blackholedev module terminating.\n");
+}
+
+module_init(test_blackholedev_init);
+module_exit(test_blackholedev_exit);
+
+MODULE_AUTHOR("Mahesh Bandewar <maheshb@google.com>");
+MODULE_LICENSE("GPL");
diff --git a/net/core/dst.c b/net/core/dst.c
index e46366228eaf..1325316d9eab 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -160,7 +160,7 @@ void dst_dev_put(struct dst_entry *dst)
dst->ops->ifdown(dst, dev, true);
dst->input = dst_discard;
dst->output = dst_discard_out;
- dst->dev = dev_net(dst->dev)->loopback_dev;
+ dst->dev = blackhole_netdev;
dev_hold(dst->dev);
dev_put(dev);
}
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index bbd55c7f6b2e..dc1f510a7c81 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1532,7 +1532,6 @@ static void ipv4_dst_destroy(struct dst_entry *dst)
void rt_flush_dev(struct net_device *dev)
{
- struct net *net = dev_net(dev);
struct rtable *rt;
int cpu;
@@ -1543,7 +1542,7 @@ void rt_flush_dev(struct net_device *dev)
list_for_each_entry(rt, &ul->head, rt_uncached) {
if (rt->dst.dev != dev)
continue;
- rt->dst.dev = net->loopback_dev;
+ rt->dst.dev = blackhole_netdev;
dev_hold(rt->dst.dev);
dev_put(dev);
}
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 7556275b1cef..39361f57351a 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -176,7 +176,7 @@ static void rt6_uncached_list_flush_dev(struct net *net, struct net_device *dev)
}
if (rt_dev == dev) {
- rt->dst.dev = loopback_dev;
+ rt->dst.dev = blackhole_netdev;
dev_hold(rt->dst.dev);
dev_put(rt_dev);
}
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 9a275d932fd5..1b24e36b4047 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -5,7 +5,7 @@ CFLAGS = -Wall -Wl,--no-as-needed -O2 -g
CFLAGS += -I../../../../usr/include/
TEST_PROGS := run_netsocktests run_afpackettests test_bpf.sh netdevice.sh \
- rtnetlink.sh xfrm_policy.sh
+ rtnetlink.sh xfrm_policy.sh test_blackhole_dev.sh
TEST_PROGS += fib_tests.sh fib-onlink-tests.sh pmtu.sh udpgso.sh ip_defrag.sh
TEST_PROGS += udpgso_bench.sh fib_rule_tests.sh msg_zerocopy.sh psock_snd.sh
TEST_PROGS += udpgro_bench.sh udpgro.sh test_vxlan_under_vrf.sh reuseport_addr_any.sh
diff --git a/tools/testing/selftests/net/config b/tools/testing/selftests/net/config
index 89f84b5118bf..e4b878d95ba0 100644
--- a/tools/testing/selftests/net/config
+++ b/tools/testing/selftests/net/config
@@ -27,3 +27,4 @@ CONFIG_NFT_CHAIN_NAT_IPV6=m
CONFIG_NFT_CHAIN_NAT_IPV4=m
CONFIG_NET_SCH_FQ=m
CONFIG_NET_SCH_ETF=m
+CONFIG_TEST_BLACKHOLE_DEV=m
diff --git a/tools/testing/selftests/net/test_blackhole_dev.sh b/tools/testing/selftests/net/test_blackhole_dev.sh
new file mode 100755
index 000000000000..3119b80e711f
--- /dev/null
+++ b/tools/testing/selftests/net/test_blackhole_dev.sh
@@ -0,0 +1,11 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Runs blackhole-dev test using blackhole-dev kernel module
+
+if /sbin/modprobe -q test_blackhole_dev ; then
+ /sbin/modprobe -q -r test_blackhole_dev;
+ echo "test_blackhole_dev: ok";
+else
+ echo "test_blackhole_dev: [FAIL]";
+ exit 1;
+fi
generated by cgit (git 2.34.1) at 2024-06-17 11:17:42 +0000