From: Toke Høiland-Jørgensen <t...@redhat.com>

This updates the test_tc_neigh selftest to use the new syntax of
bpf_redirect_neigh(). To exercise the helper both with and without the
optional parameter, one forwarding direction is changed to do a
bpf_fib_lookup() followed by a call to bpf_redirect_neigh(), while the
other direction is using the map-based ifindex lookup letting the redirect
helper resolve the nexthop from the FIB.

This also fixes the test_tc_redirect.sh script to work on systems that have
a consolidated dual-stack 'ping' binary instead of separate ping/ping6
versions.

Signed-off-by: Toke Høiland-Jørgensen <t...@redhat.com>
---
 tools/testing/selftests/bpf/progs/test_tc_neigh.c |   83 ++++++++++++++++++---
 tools/testing/selftests/bpf/test_tc_redirect.sh   |    8 +-
 2 files changed, 78 insertions(+), 13 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/test_tc_neigh.c 
b/tools/testing/selftests/bpf/progs/test_tc_neigh.c
index fe182616b112..ba03e603ba9b 100644
--- a/tools/testing/selftests/bpf/progs/test_tc_neigh.c
+++ b/tools/testing/selftests/bpf/progs/test_tc_neigh.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <stdint.h>
 #include <stdbool.h>
+#include <stddef.h>
 
 #include <linux/bpf.h>
 #include <linux/stddef.h>
@@ -32,6 +33,9 @@
                                 a.s6_addr32[3] == b.s6_addr32[3])
 #endif
 
+#define AF_INET 2
+#define AF_INET6 10
+
 enum {
        dev_src,
        dev_dst,
@@ -45,7 +49,8 @@ struct bpf_map_def SEC("maps") ifindex_map = {
 };
 
 static __always_inline bool is_remote_ep_v4(struct __sk_buff *skb,
-                                           __be32 addr)
+                                           __be32 addr,
+                                           struct bpf_fib_lookup *fib_params)
 {
        void *data_end = ctx_ptr(skb->data_end);
        void *data = ctx_ptr(skb->data);
@@ -58,11 +63,26 @@ static __always_inline bool is_remote_ep_v4(struct 
__sk_buff *skb,
        if ((void *)(ip4h + 1) > data_end)
                return false;
 
-       return ip4h->daddr == addr;
+       if (ip4h->daddr != addr)
+               return false;
+
+       if (fib_params) {
+               fib_params->family = AF_INET;
+               fib_params->tos = ip4h->tos;
+               fib_params->l4_protocol = ip4h->protocol;
+               fib_params->sport = 0;
+               fib_params->dport = 0;
+               fib_params->tot_len = bpf_ntohs(ip4h->tot_len);
+               fib_params->ipv4_src = ip4h->saddr;
+               fib_params->ipv4_dst = ip4h->daddr;
+       }
+
+       return true;
 }
 
 static __always_inline bool is_remote_ep_v6(struct __sk_buff *skb,
-                                           struct in6_addr addr)
+                                           struct in6_addr addr,
+                                           struct bpf_fib_lookup *fib_params)
 {
        void *data_end = ctx_ptr(skb->data_end);
        void *data = ctx_ptr(skb->data);
@@ -75,7 +95,24 @@ static __always_inline bool is_remote_ep_v6(struct __sk_buff 
*skb,
        if ((void *)(ip6h + 1) > data_end)
                return false;
 
-       return v6_equal(ip6h->daddr, addr);
+       if (!v6_equal(ip6h->daddr, addr))
+               return false;
+
+       if (fib_params) {
+               struct in6_addr *src = (struct in6_addr *)fib_params->ipv6_src;
+               struct in6_addr *dst = (struct in6_addr *)fib_params->ipv6_dst;
+
+               fib_params->family = AF_INET6;
+               fib_params->flowinfo = 0;
+               fib_params->l4_protocol = ip6h->nexthdr;
+               fib_params->sport = 0;
+               fib_params->dport = 0;
+               fib_params->tot_len = bpf_ntohs(ip6h->payload_len);
+               *src = ip6h->saddr;
+               *dst = ip6h->daddr;
+       }
+
+       return true;
 }
 
 static __always_inline int get_dev_ifindex(int which)
@@ -99,15 +136,17 @@ SEC("chk_egress") int tc_chk(struct __sk_buff *skb)
 
 SEC("dst_ingress") int tc_dst(struct __sk_buff *skb)
 {
+       struct bpf_fib_lookup fib_params = { .ifindex = skb->ingress_ifindex };
        __u8 zero[ETH_ALEN * 2];
        bool redirect = false;
+       int ret;
 
        switch (skb->protocol) {
        case __bpf_constant_htons(ETH_P_IP):
-               redirect = is_remote_ep_v4(skb, __bpf_constant_htonl(ip4_src));
+               redirect = is_remote_ep_v4(skb, __bpf_constant_htonl(ip4_src), 
&fib_params);
                break;
        case __bpf_constant_htons(ETH_P_IPV6):
-               redirect = is_remote_ep_v6(skb, (struct in6_addr)ip6_src);
+               redirect = is_remote_ep_v6(skb, (struct in6_addr)ip6_src, 
&fib_params);
                break;
        }
 
@@ -118,7 +157,31 @@ SEC("dst_ingress") int tc_dst(struct __sk_buff *skb)
        if (bpf_skb_store_bytes(skb, 0, &zero, sizeof(zero), 0) < 0)
                return TC_ACT_SHOT;
 
-       return bpf_redirect_neigh(get_dev_ifindex(dev_src), 0);
+       ret = bpf_fib_lookup(skb, &fib_params, sizeof(fib_params), 0);
+       bpf_printk("bpf_fib_lookup() ret: %d\n", ret);
+       if (ret == BPF_FIB_LKUP_RET_SUCCESS) {
+               void *data_end = ctx_ptr(skb->data_end);
+               struct ethhdr *eth = ctx_ptr(skb->data);
+
+               if (eth + 1 > data_end)
+                       return TC_ACT_SHOT;
+
+               __builtin_memcpy(eth->h_dest, fib_params.dmac, ETH_ALEN);
+               __builtin_memcpy(eth->h_source, fib_params.smac, ETH_ALEN);
+
+               return bpf_redirect(fib_params.ifindex, 0);
+
+       } else if (ret == BPF_FIB_LKUP_RET_NO_NEIGH) {
+               struct bpf_redir_neigh nh_params = {};
+
+               nh_params.nh_family = fib_params.family;
+               __builtin_memcpy(&nh_params.ipv6_nh, &fib_params.ipv6_dst,
+                                sizeof(nh_params.ipv6_nh));
+
+               return bpf_redirect_neigh(fib_params.ifindex, &nh_params,
+                                         sizeof(nh_params), 0);
+       }
+       return TC_ACT_SHOT;
 }
 
 SEC("src_ingress") int tc_src(struct __sk_buff *skb)
@@ -128,10 +191,10 @@ SEC("src_ingress") int tc_src(struct __sk_buff *skb)
 
        switch (skb->protocol) {
        case __bpf_constant_htons(ETH_P_IP):
-               redirect = is_remote_ep_v4(skb, __bpf_constant_htonl(ip4_dst));
+               redirect = is_remote_ep_v4(skb, __bpf_constant_htonl(ip4_dst), 
NULL);
                break;
        case __bpf_constant_htons(ETH_P_IPV6):
-               redirect = is_remote_ep_v6(skb, (struct in6_addr)ip6_dst);
+               redirect = is_remote_ep_v6(skb, (struct in6_addr)ip6_dst, NULL);
                break;
        }
 
@@ -142,7 +205,7 @@ SEC("src_ingress") int tc_src(struct __sk_buff *skb)
        if (bpf_skb_store_bytes(skb, 0, &zero, sizeof(zero), 0) < 0)
                return TC_ACT_SHOT;
 
-       return bpf_redirect_neigh(get_dev_ifindex(dev_dst), 0);
+       return bpf_redirect_neigh(get_dev_ifindex(dev_dst), NULL, 0, 0);
 }
 
 char __license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/test_tc_redirect.sh 
b/tools/testing/selftests/bpf/test_tc_redirect.sh
index 6d7482562140..09b20f24d018 100755
--- a/tools/testing/selftests/bpf/test_tc_redirect.sh
+++ b/tools/testing/selftests/bpf/test_tc_redirect.sh
@@ -24,8 +24,7 @@ command -v timeout >/dev/null 2>&1 || \
        { echo >&2 "timeout is not available"; exit 1; }
 command -v ping >/dev/null 2>&1 || \
        { echo >&2 "ping is not available"; exit 1; }
-command -v ping6 >/dev/null 2>&1 || \
-       { echo >&2 "ping6 is not available"; exit 1; }
+if command -v ping6 >/dev/null 2>&1; then PING6=ping6; else PING6=ping; fi
 command -v perl >/dev/null 2>&1 || \
        { echo >&2 "perl is not available"; exit 1; }
 command -v jq >/dev/null 2>&1 || \
@@ -152,7 +151,7 @@ netns_test_connectivity()
        echo -e "${TEST}: ${GREEN}PASS${NC}"
 
        TEST="ICMPv6 connectivity test"
-       ip netns exec ${NS_SRC} ping6 $PING_ARG ${IP6_DST}
+       ip netns exec ${NS_SRC} $PING6 $PING_ARG ${IP6_DST}
        if [ $? -ne 0 ]; then
                echo -e "${TEST}: ${RED}FAIL${NC}"
                exit 1
@@ -179,6 +178,9 @@ netns_setup_bpf()
        ip netns exec ${NS_FWD} tc filter add dev veth_dst_fwd ingress bpf da 
obj $obj sec dst_ingress
        ip netns exec ${NS_FWD} tc filter add dev veth_dst_fwd egress  bpf da 
obj $obj sec chk_egress
 
+       # bpf_fib_lookup() checks if forwarding is enabled
+       ip netns exec ${NS_FWD} sysctl -w net.ipv4.ip_forward=1 
net.ipv6.conf.veth_dst_fwd.forwarding=1
+
        veth_src=$(ip netns exec ${NS_FWD} cat 
/sys/class/net/veth_src_fwd/ifindex)
        veth_dst=$(ip netns exec ${NS_FWD} cat 
/sys/class/net/veth_dst_fwd/ifindex)
 

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