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bpf: Run generic devmap egress prog on private skb #8032

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10 changes: 10 additions & 0 deletions kernel/bpf/devmap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -700,12 +700,22 @@ int dev_map_enqueue_multi(struct xdp_frame *xdpf, struct net_device *dev_rx,
int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
const struct bpf_prog *xdp_prog)
{
struct sk_buff *nskb;
int err;

err = xdp_ok_fwd_dev(dst->dev, skb->len);
if (unlikely(err))
return err;

if (dst->xdp_prog && skb_cloned(skb)) {
nskb = skb_copy(skb, GFP_ATOMIC);
if (!nskb)
return -ENOMEM;

consume_skb(skb);
skb = nskb;
}

/* Redirect has already succeeded semantically at this point, so we just
* return 0 even if packet is dropped. Helper below takes care of
* freeing skb.
Expand Down
151 changes: 148 additions & 3 deletions tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c
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Original file line number Diff line number Diff line change
Expand Up @@ -456,7 +456,11 @@ static void xdp_veth_egress(u32 flags)
.remote_flags = flags,
}
};
const char magic_mac[6] = { 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF};
const unsigned char egress_macs[VETH_PAIRS_COUNT][ETH_ALEN] = {
{ 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0x01 },
{ 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0x02 },
{ 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0x03 },
};
struct xdp_redirect_multi_kern *xdp_redirect_multi_kern;
struct bpf_object *bpf_objs[VETH_EGRESS_SKEL_NB];
struct xdp_redirect_map *xdp_redirect_map;
Expand Down Expand Up @@ -512,7 +516,7 @@ static void xdp_veth_egress(u32 flags)
&net_config, prog_cfg, i))
goto destroy_xdp_redirect_map;

err = bpf_map_update_elem(mac_map, &ifindex, magic_mac, 0);
err = bpf_map_update_elem(mac_map, &ifindex, egress_macs[i], 0);
if (!ASSERT_OK(err, "bpf_map_update_elem"))
goto destroy_xdp_redirect_map;

Expand All @@ -531,13 +535,16 @@ static void xdp_veth_egress(u32 flags)

for (i = 0; i < 2; i++) {
u32 key = i;
__be64 expected = 0;
u64 res;

err = bpf_map_lookup_elem(res_map, &key, &res);
if (!ASSERT_OK(err, "get MAC res"))
goto destroy_xdp_redirect_map;

ASSERT_STRNEQ((const char *)&res, magic_mac, ETH_ALEN, "compare mac");
/* store_mac_1/2 run on the second/third remote veths. */
memcpy(&expected, egress_macs[i + 1], ETH_ALEN);
ASSERT_EQ(res, expected, "compare mac");
}

destroy_xdp_redirect_map:
Expand All @@ -551,6 +558,141 @@ static void xdp_veth_egress(u32 flags)
cleanup_network(&net_config);
}

static void xdp_veth_egress_last_dst(u32 flags)
{
struct prog_configuration prog_cfg[VETH_PAIRS_COUNT] = {
{
.local_name = "xdp_redirect_map_all_prog",
.remote_name = "store_mac_1",
.local_flags = flags,
.remote_flags = flags,
},
{
.local_name = "xdp_redirect_map_all_prog",
.remote_name = "store_mac_2",
.local_flags = flags,
.remote_flags = flags,
},
{
.local_name = "xdp_redirect_map_all_prog",
.remote_name = "xdp_dummy_prog",
.local_flags = flags,
.remote_flags = flags,
}
};
const unsigned char egress_macs[VETH_PAIRS_COUNT][ETH_ALEN] = {
{ 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0x01 },
{ 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0x02 },
{ 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0x03 },
};
struct xdp_redirect_multi_kern *xdp_redirect_multi_kern;
struct bpf_object *bpf_objs[VETH_EGRESS_SKEL_NB];
struct xdp_redirect_map *xdp_redirect_map;
struct net_configuration net_config;
int mac_map, egress_map, res_map;
struct nstoken *nstoken = NULL;
struct xdp_dummy *xdp_dummy;
__be64 last_mac = 0;
bool found = false;
int err;
int i;

xdp_dummy = xdp_dummy__open_and_load();
if (!ASSERT_OK_PTR(xdp_dummy, "xdp_dummy__open_and_load"))
return;

xdp_redirect_multi_kern = xdp_redirect_multi_kern__open_and_load();
if (!ASSERT_OK_PTR(xdp_redirect_multi_kern, "xdp_redirect_multi_kern__open_and_load"))
goto destroy_xdp_dummy;

xdp_redirect_map = xdp_redirect_map__open_and_load();
if (!ASSERT_OK_PTR(xdp_redirect_map, "xdp_redirect_map__open_and_load"))
goto destroy_xdp_redirect_multi_kern;

if (!ASSERT_OK(create_network(&net_config), "create network"))
goto destroy_xdp_redirect_map;

mac_map = bpf_map__fd(xdp_redirect_multi_kern->maps.mac_map);
if (!ASSERT_OK_FD(mac_map, "open mac_map"))
goto destroy_xdp_redirect_map;

egress_map = bpf_map__fd(xdp_redirect_multi_kern->maps.map_egress);
if (!ASSERT_OK_FD(egress_map, "open map_egress"))
goto destroy_xdp_redirect_map;

bpf_objs[0] = xdp_dummy->obj;
bpf_objs[1] = xdp_redirect_multi_kern->obj;
bpf_objs[2] = xdp_redirect_map->obj;

nstoken = open_netns(net_config.ns0_name);
if (!ASSERT_OK_PTR(nstoken, "open NS0"))
goto destroy_xdp_redirect_map;

for (i = 0; i < VETH_PAIRS_COUNT; i++) {
struct bpf_devmap_val devmap_val = {};
int ifindex = if_nametoindex(net_config.veth_cfg[i].local_veth);

SYS(destroy_xdp_redirect_map,
"ip -n %s neigh add %s lladdr 00:00:00:00:00:01 dev %s",
net_config.veth_cfg[i].namespace, IP_NEIGH,
net_config.veth_cfg[i].remote_veth);

if (attach_programs_to_veth_pair(bpf_objs, VETH_EGRESS_SKEL_NB,
&net_config, prog_cfg, i))
goto destroy_xdp_redirect_map;

err = bpf_map_update_elem(mac_map, &ifindex, egress_macs[i], 0);
if (!ASSERT_OK(err, "bpf_map_update_elem"))
goto destroy_xdp_redirect_map;

devmap_val.ifindex = ifindex;
devmap_val.bpf_prog.fd = -1;

if (i == VETH_PAIRS_COUNT - 1)
devmap_val.bpf_prog.fd =
bpf_program__fd(xdp_redirect_multi_kern->progs.xdp_devmap_prog);

err = bpf_map_update_elem(egress_map, &ifindex, &devmap_val, 0);
if (!ASSERT_OK(err, "bpf_map_update_elem"))
goto destroy_xdp_redirect_map;
}

SYS_NOFAIL("ip netns exec %s ping %s -i 0.1 -c 4 -W1 > /dev/null ",
net_config.veth_cfg[0].namespace, IP_NEIGH);

res_map = bpf_map__fd(xdp_redirect_map->maps.rx_mac);
if (!ASSERT_OK_FD(res_map, "open rx_map"))
goto destroy_xdp_redirect_map;

memcpy(&last_mac, egress_macs[VETH_PAIRS_COUNT - 1], ETH_ALEN);

for (i = 0; i < VETH_PAIRS_COUNT - 1; i++) {
u32 key = i;
u64 res;

err = bpf_map_lookup_elem(res_map, &key, &res);
if (err == -ENOENT)
continue;
if (!ASSERT_OK(err, "get MAC res"))
goto destroy_xdp_redirect_map;

found = true;
ASSERT_NEQ(res, last_mac, "compare last dst mac");
}

ASSERT_TRUE(found, "found earlier dst mac");

destroy_xdp_redirect_map:
close_netns(nstoken);
xdp_redirect_map__destroy(xdp_redirect_map);
destroy_xdp_redirect_multi_kern:
xdp_redirect_multi_kern__destroy(xdp_redirect_multi_kern);
destroy_xdp_dummy:
xdp_dummy__destroy(xdp_dummy);

cleanup_network(&net_config);
}

void test_xdp_veth_redirect(void)
{
if (test__start_subtest("0"))
Expand Down Expand Up @@ -596,4 +738,7 @@ void test_xdp_veth_egress(void)

if (test__start_subtest("SKB_MODE/egress"))
xdp_veth_egress(XDP_FLAGS_SKB_MODE);

if (test__start_subtest("SKB_MODE/egress_last_dst"))
xdp_veth_egress_last_dst(XDP_FLAGS_SKB_MODE);
}