fix: remove deref_to_depth on single depth pointers

Author: varun-r-mallya

pythonbpf/expr/expr_pass.py

@@ -241,7 +241,11 @@ def get_operand_value(
             var_type = var.type
             base_type, depth = get_base_type_and_depth(var_type)
             logger.info(f"var is {var}, base_type is {base_type}, depth is {depth}")
-            val = deref_to_depth(func, builder, var, depth)
+            if depth == 1:
+                val = builder.load(var)
+                return val
+            else:
+                val = deref_to_depth(func, builder, var, depth)
             return val
         else:
             # Check if it's a vmlinux enum/constant

tests/c-form/xdp_test.bpf.c

@@ -1,38 +1,36 @@
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
 #include <linux/bpf.h>
 #include <linux/if_ether.h>
 #include <linux/ip.h>
-#include <bpf/bpf_helpers.h>
 
 struct fake_iphdr {
-    unsigned short useless;
-    unsigned short tot_len;
-    unsigned short id;
-    unsigned short frag_off;
-    unsigned char  ttl;
-    unsigned char  protocol;
-    unsigned short check;
-    unsigned int saddr;
-    unsigned int daddr;
+  unsigned short useless;
+  unsigned short tot_len;
+  unsigned short id;
+  unsigned short frag_off;
+  unsigned char ttl;
+  unsigned char protocol;
+  unsigned short check;
+  unsigned int saddr;
+  unsigned int daddr;
 };
 
 SEC("xdp")
-int xdp_prog(struct xdp_md *ctx)
-{
-    void *data_end = (void *)(long)ctx->data_end;
-    void *data     = (void *)(long)ctx->data;
+int xdp_prog(struct xdp_md *ctx) {
+  unsigned long data = ctx->data;
+  unsigned long data_end = ctx->data_end;
 
-    struct ethhdr *eth = data;
-    if ((void *)(eth + 1) > data_end)
-        return XDP_ABORTED;
-    if (eth->h_proto != __constant_htons(ETH_P_IP))
-        return XDP_PASS;
+  if (data + sizeof(struct ethhdr) + sizeof(struct fake_iphdr) <= data_end) {
+    struct fake_iphdr *iph = (void *)data + sizeof(struct ethhdr);
 
-    struct fake_iphdr *iph = (struct fake_iphdr *)(eth + 1);
-    if ((void *)(iph + 1) > data_end)
-        return XDP_ABORTED;
     bpf_printk("%d", iph->saddr);
 
     return XDP_PASS;
+  } else {
+    return XDP_ABORTED;
+  }
+  struct task_struct * a = btf_bpf_get_current_task_btf();
 }
 
 char _license[] SEC("license") = "GPL";

tests/failing_tests/xdp/xdp_test_1.py

@@ -1,10 +1,9 @@
-from vmlinux import XDP_PASS, XDP_DROP
+from vmlinux import XDP_PASS, XDP_ABORTED
 from vmlinux import (
     struct_xdp_md,
-    struct_ethhdr,
 )
 from pythonbpf import bpf, section, bpfglobal, compile, compile_to_ir, struct
-from ctypes import c_int64, c_ubyte, c_ushort, c_uint32
+from ctypes import c_int64, c_ubyte, c_ushort, c_uint32, c_void_p
 
 
 @bpf
@@ -24,19 +23,15 @@ class iphdr:
 @bpf
 @section("xdp")
 def ip_detector(ctx: struct_xdp_md) -> c_int64:
-    data = ctx.data
-    data_end = ctx.data_end
-    if data + 14 > data_end:
-        return c_int64(XDP_DROP)
-
-    eth = struct_ethhdr(data)
-    nh = data + 14
-    if nh + 20 > data_end:
-        return c_int64(XDP_DROP)
-
-    iph = iphdr(nh)
-
-    print(f"ipaddress: {iph.saddr}")
+    data = c_void_p(ctx.data)
+    data_end = c_void_p(ctx.data_end)
+    if data + 34 < data_end:
+        hdr = data + 14
+        iph = iphdr(hdr)
+        addr = iph.saddr
+        print(f"ipaddress: {addr}")
+    else:
+        return c_int64(XDP_ABORTED)
 
     return c_int64(XDP_PASS)
 

tests/passing_tests/assign/ptr_to_char_array.py

@@ -1,4 +1,4 @@
-from pythonbpf import bpf, struct, section, bpfglobal
+from pythonbpf import bpf, struct, section, bpfglobal, compile
 from pythonbpf.helper import comm
 
 from ctypes import c_void_p, c_int64
@@ -26,3 +26,6 @@ def hello(ctx: c_void_p) -> c_int64:
 @bpfglobal
 def LICENSE() -> str:
     return "GPL"
+
+
+compile()