sys/linux: update BPF_MAP_UPDATE_ELEM to enable more thorough sockmap fuzzing

sockmap and sockhash expect the value of the update syscall to be a file
descriptor for a UDP or TCP socket. Add this knowledge by introducing a
separate union for map update values.

1 files changed, 9 insertions, 1 deletions

diff --git a/sys/linux/bpf.txt b/sys/linux/bpf.txt
index 9fef31e31..981bf5036 100644
--- a/sys/linux/bpf.txt
+++ b/sys/linux/bpf.txt
@@ -96,10 +96,18 @@ bpf_map_lookup_arg {
 	flags	flags[bpf_lookup_flags, int64]
 }
 
+bpf_map_update_val [
+	buf	array[int8]
+	udp	sock_udp
+	udp6	sock_udp6
+	tcp	sock_tcp
+	tcp6	sock_tcp6
+] [varlen]
+
 bpf_map_update_arg {
 	map	fd_bpf_map
 	key	ptr64[in, array[int8]]
-	val	ptr64[in, array[int8]]
+	val	ptr64[in, bpf_map_update_val]
 	flags	flags[bpf_map_flags, int64]
 }