Add ubpf support via UBPF_jll

Author: jpsamaroo

Manifest.toml

@@ -12,13 +12,15 @@ Libbpf_jll = "02f9a84d-9555-5f1a-8c3c-42027521038d"
 Libdl = "8f399da3-3557-5675-b5ff-fb832c97cbdb"
 Preferences = "21216c6a-2e73-6563-6e65-726566657250"
 Sockets = "6462fe0b-24de-5631-8697-dd941f90decc"
+UBPF_jll = "502467ad-4a4a-57e4-9860-6b433130b33f"
 
 [compat]
 CBinding = "1"
 GPUCompiler = "0.11"
 LLVM = "3.6"
 Libbpf_jll = "0.3"
 Preferences = "1"
+UBPF_jll = "0.0.2"
 julia = "1.6"
 
 [extras]

Project.toml

@@ -30,6 +30,12 @@ function enable_vmlinux(ans::Bool=true)
     end
 end
 
+# ubpf VM
+module UBPF
+using UBPF_jll
+include("ubpf.jl")
+end
+
 # Common API
 module API
 if !parse(Bool, get(ENV, "JULIA_BPFNATIVE_DISABLE_ARTIFACTS", "0"))

src/BPFnative.jl

@@ -0,0 +1,75 @@
+export call, verify, load_elf
+
+struct ebpf_inst
+    opcode::UInt8
+    dst_src::UInt8
+    offset::Int16
+    imm::Int32
+end
+const ubpf_jit_fn = Ptr{Cvoid}
+const ext_func = Ptr{Cvoid}
+Base.@kwdef struct ubpf_vm
+    insts::Ptr{ebpf_inst}
+    num_insts::UInt16
+    jitted::ubpf_jit_fn = C_NULL
+    jitted_size::Csize_t = 0
+    ext_funcs::Ptr{ext_func} = C_NULL
+    ext_func_names::Ptr{Cstring} = C_NULL
+    bounds_check_enabled::Bool = true
+end
+ubpf_vm(exe::Vector{ebpf_inst}; kwargs...) =
+    ubpf_vm(pointer(exe), length(exe); kwargs...)
+ubpf_vm(exe::Vector{UInt8}; kwargs...) =
+    ubpf_vm(reinterpret(Ptr{ebpf_inst}, pointer(exe)),
+            div(length(exe),sizeof(ebpf_inst));
+            kwargs...)
+
+call(exe::Vector{UInt8}, mem::Vector{UInt8}; kwargs...) =
+    call(collect(reinterpret(ebpf_inst, exe)), mem; kwargs...)
+function call(exe::Vector{ebpf_inst}, mem::Vector{UInt8}; kwargs...)
+    GC.@preserve exe mem begin
+        vm = ubpf_vm(exe; kwargs...)
+        if verify(vm) == 0
+            unsafe_call(vm, mem)
+        else
+            error("BPF verification failed")
+        end
+    end
+end
+function verify(vm::ubpf_vm)
+    vm_ref = Ref(vm)
+    GC.@preserve vm_ref begin
+        ccall((:ubpf_verify, libubpf), Cint, (Ptr{ubpf_vm},), vm_ref)
+    end
+end
+function unsafe_call(vm::ubpf_vm, mem::Union{<:Ptr,<:Integer}, mem_len::Integer)
+    vm_ref = Ref(vm)
+    mem = sizeof(mem) < sizeof(Ptr{Cvoid}) ? UInt(mem) : mem
+    GC.@preserve vm_ref mem begin
+        ccall((:ubpf_exec, libubpf), UInt64,
+              (Ptr{ubpf_vm}, Ptr{Cvoid}, Csize_t),
+              vm_ref, reinterpret(Ptr{Cvoid}, mem), mem_len)
+    end
+end
+function unsafe_call(vm::ubpf_vm, mem::Vector{UInt8})
+    vm_ref = Ref(vm)
+    GC.@preserve vm_ref mem begin
+        ccall((:ubpf_exec, libubpf), UInt64,
+              (Ptr{ubpf_vm}, Ptr{Cvoid}, Csize_t),
+              vm_ref, mem, length(mem))
+    end
+end
+function load_elf(vm::ubpf_vm, exe::Vector{UInt8})
+    vm_ref = Ref(vm)
+    errmsg = Ref{Cstring}()
+    ret = GC.@preserve vm_ref errmsg begin
+        ccall((:ubpf_load_elf, libubpf), Cint,
+              (Ptr{ubpf_vm}, Ptr{UInt8}, Csize_t, Ptr{Cstring}),
+              vm_ref, pointer(exe), length(exe), errmsg)
+    end
+    if ret != 0
+        error(unsafe_string(errmsg[]))
+    end
+    vm_ref[]
+end
+load_elf(path::String) = load_elf(read(path))