Panic when net.netfilter.nf_conntrack_log_invalid is nonzero

[muff1nman]

panic: runtime error: index out of range [3] with length 2

goroutine 594 [running]:
main.lookupRule(0x79f540, 0xc00019a6e0, 0xc00042c360, 0x1c, 0xc000898d80, 0x0)
	/home/andrew/Source/github/eiginn/nftrace/cmd/nftrace/main.go:127 +0x855
main.main.func3(0xc000898d24, 0x0, 0xc00041b980, 0x0, 0x0, 0x0, 0x0, 0xc00041b9a0, 0xc000419ed0, 0x0, ...)
	/home/andrew/Source/github/eiginn/nftrace/cmd/nftrace/main.go:258 +0x208
github.com/florianl/go-nflog.(*Nflog).Register.func1(0xc000346780, 0xc0d673d5ba, 0xc0004c87a0, 0x79b7c0, 0xc0004fb260, 0x747800)
	/home/andrew/Source/github/eiginn/nftrace/vendor/github.com/florianl/go-nflog/nflog.go:236 +0x349
created by github.com/florianl/go-nflog.(*Nflog).Register
	/home/andrew/Source/github/eiginn/nftrace/vendor/github.com/florianl/go-nflog/nflog.go:197 +0x6d3