[PATCH bpf-next v5 1/2] bpf: setup socket family and addresses in bpf_prog_test_run_skb

[Dmitry Yakunin]

Now it's impossible to test all branches of cgroup_skb bpf program which
accesses skb->family and skb->{local,remote}_ip{4,6} fields because they
are zeroed during socket allocation. This commit fills socket family and
addresses from related fields in constructed skb.

v2:
  - fix build without CONFIG_IPV6 (kernel test robot <l...@intel.com>)

v3:
  - check skb length before access to inet headers (Eric Dumazet)

Signed-off-by: Dmitry Yakunin <z...@yandex-team.ru>
---
 net/bpf/test_run.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index b03c469..8d69295 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -449,6 +449,27 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const 
union bpf_attr *kattr,
        skb->protocol = eth_type_trans(skb, 
current->nsproxy->net_ns->loopback_dev);
        skb_reset_network_header(skb);
 
+       switch (skb->protocol) {
+       case htons(ETH_P_IP):
+               sk->sk_family = AF_INET;
+               if (pskb_may_pull(skb, sizeof(struct iphdr))) {
+                       sk->sk_rcv_saddr = ip_hdr(skb)->saddr;
+                       sk->sk_daddr = ip_hdr(skb)->daddr;
+               }
+               break;
+#if IS_ENABLED(CONFIG_IPV6)
+       case htons(ETH_P_IPV6):
+               sk->sk_family = AF_INET6;
+               if (pskb_may_pull(skb, sizeof(struct ipv6hdr))) {
+                       sk->sk_v6_rcv_saddr = ipv6_hdr(skb)->saddr;
+                       sk->sk_v6_daddr = ipv6_hdr(skb)->daddr;
+               }
+               break;
+#endif
+       default:
+               break;
+       }
+
        if (is_l2)
                __skb_push(skb, hh_len);
        if (is_direct_pkt_access)
-- 
2.7.4