src/ebpf.rs: Increase instruction limit to 1 million

The linux kernel allows programs of 1 million instructions, see

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c04c0d2b968ac45d6ef020316808ef6c82325a82

I'm hitting the 4096 limit in some corner cases with
https://github.com/seanyoung/cir, if the infrared protocol is very
complex (e.g. XMP). rbpf is used for testing the generated IR decoders
in the test framework.

Signed-off-by: Sean Young <sean@mess.org>

src/ebpf.rs

@@ -17,7 +17,7 @@
 use byteorder::{ByteOrder, LittleEndian};
 
 /// Maximum number of instructions in an eBPF program.
-pub const PROG_MAX_INSNS: usize = 4096;
+pub const PROG_MAX_INSNS: usize = 1000000;
 /// Size of an eBPF instructions, in bytes.
 pub const INSN_SIZE: usize = 8;
 /// Maximum size of an eBPF program, in bytes.

tests/ubpf_verifier.rs

@@ -115,11 +115,11 @@ fn test_verifier_err_no_exit_backward_jump() {
 }
 
 #[test]
-#[should_panic(expected = "[Verifier] Error: eBPF program length limited to 4096, here 4097")]
+#[should_panic(expected = "[Verifier] Error: eBPF program length limited to 1000000, here 1000001")]
 fn test_verifier_err_too_many_instructions() {
     // uBPF uses 65637 instructions, because it sets its limit at 65636.
     // We use the classic 4096 limit from kernel, so no need to produce as many instructions.
-    let mut prog = (0..(4096 * ebpf::INSN_SIZE)).map( |x| match x % 8 {
+    let mut prog = (0..(1_000_000 * ebpf::INSN_SIZE)).map( |x| match x % 8 {
             0 => 0xb7,
             1 => 0x01,
             _ => 0