bpf: Add sock_ops R/W access to ipv4 tos

Sample usage for tos ...

  bpf_getsockopt(skops, SOL_IP, IP_TOS, &v, sizeof(v))

... where skops is a pointer to the ctx (struct bpf_sock_ops).

Signed-off-by: Nikita V. Shirokov <tehnerd@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 35 insertions, 0 deletions

diff --git a/net/core/filter.c b/net/core/filter.c
index 00c711c5f1a2..afd825534ac4 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3462,6 +3462,27 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, bpf_sock,
                         ret = -EINVAL;
                 }
 #ifdef CONFIG_INET
+        } else if (level == SOL_IP) {
+                if (optlen != sizeof(int) || sk->sk_family != AF_INET)
+                        return -EINVAL;
+
+                val = *((int *)optval);
+                /* Only some options are supported */
+                switch (optname) {
+                case IP_TOS:
+                        if (val < -1 || val > 0xff) {
+                                ret = -EINVAL;
+                        } else {
+                                struct inet_sock *inet = inet_sk(sk);
+
+                                if (val == -1)
+                                        val = 0;
+                                inet->tos = val;
+                        }
+                        break;
+                default:
+                        ret = -EINVAL;
+                }
 #if IS_ENABLED(CONFIG_IPV6)
         } else if (level == SOL_IPV6) {
                 if (optlen != sizeof(int) || sk->sk_family != AF_INET6)
@@ -3561,6 +3582,20 @@ BPF_CALL_5(bpf_getsockopt, struct bpf_sock_ops_kern *, bpf_sock,
                 } else {
                         goto err_clear;
                 }
+        } else if (level == SOL_IP) {
+                struct inet_sock *inet = inet_sk(sk);
+
+                if (optlen != sizeof(int) || sk->sk_family != AF_INET)
+                        goto err_clear;
+
+                /* Only some options are supported */
+                switch (optname) {
+                case IP_TOS:
+                        *((int *)optval) = (int)inet->tos;
+                        break;
+                default:
+                        goto err_clear;
+                }
 #if IS_ENABLED(CONFIG_IPV6)
         } else if (level == SOL_IPV6) {
                 struct ipv6_pinfo *np = inet6_sk(sk);