feat:user defined struct casting

tests/c-form/xdp_test.bpf.c

@@ -1,72 +1,38 @@
-// xdp_ip_map.c
 #include <linux/bpf.h>
-#include <bpf/bpf_helpers.h>
-#include <bpf/bpf_endian.h>
 #include <linux/if_ether.h>
 #include <linux/ip.h>
+#include <bpf/bpf_helpers.h>
 
-struct ip_key {
-   __u8 family;     // 4 = IPv4
-   __u8 pad[3];     // padding for alignment
-   __u8 addr[16];   // IPv4 uses first 4 bytes
+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;
 };
 
-// key → packet count
-struct {
-   __uint(type, BPF_MAP_TYPE_HASH);
-   __uint(max_entries, 16384);
-   __type(key, struct ip_key);
-   __type(value, __u64);
-} ip_count_map SEC(".maps");
-
 SEC("xdp")
-int xdp_ip_map(struct xdp_md *ctx)
+int xdp_prog(struct xdp_md *ctx)
 {
-   void *data_end = (void *)(long)ctx->data_end;
-   void *data     = (void *)(long)ctx->data;
-   struct ethhdr *eth = data;
+    void *data_end = (void *)(long)ctx->data_end;
+    void *data     = (void *)(long)ctx->data;
 
-   if (eth + 1 > (struct ethhdr *)data_end)
-       return XDP_PASS;
+    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;
 
-   __u16 h_proto = eth->h_proto;
-   void *nh = data + sizeof(*eth);
+    struct fake_iphdr *iph = (struct fake_iphdr *)(eth + 1);
+    if ((void *)(iph + 1) > data_end)
+        return XDP_ABORTED;
+    bpf_printk("%d", iph->saddr);
 
-   // VLAN handling: single tag
-   if (h_proto == bpf_htons(ETH_P_8021Q) ||
-       h_proto == bpf_htons(ETH_P_8021AD)) {
-
-       if (nh + 4 > data_end)
-           return XDP_PASS;
-
-       h_proto = *(__u16 *)(nh + 2);
-       nh += 4;
-   }
-
-   struct ip_key key = {};
-
-   // IPv4
-   if (h_proto == bpf_htons(ETH_P_IP)) {
-       struct iphdr *iph = nh;
-       if (iph + 1 > (struct iphdr *)data_end)
-           return XDP_PASS;
-
-       key.family = 4;
-       // Copy 4 bytes of IPv4 address
-       __builtin_memcpy(key.addr, &iph->saddr, 4);
-
-       __u64 *val = bpf_map_lookup_elem(&ip_count_map, &key);
-       if (val)
-           (*val)++;
-       else {
-           __u64 init = 1;
-           bpf_map_update_elem(&ip_count_map, &key, &init, BPF_ANY);
-       }
-
-       return XDP_PASS;
-   }
-
-   return XDP_PASS;
+    return XDP_PASS;
 }
 
 char _license[] SEC("license") = "GPL";

tests/failing_tests/xdp/xdp_test_1.py

@@ -0,0 +1,46 @@
+from vmlinux import XDP_PASS, XDP_DROP
+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
+
+@bpf
+@struct
+class iphdr:
+    useless: c_ushort
+    tot_len: c_ushort
+    id: c_ushort
+    frag_off: c_ushort
+    ttl: c_ubyte
+    protocol: c_ubyte
+    check: c_ushort
+    saddr: c_uint32
+    daddr: c_uint32
+
+@bpf
+@section("xdp")
+def ip_detector(ctx: struct_xdp_md) -> c_int64:
+    data = ctx.data
+    data_end = ctx.data_end
+    eth = struct_ethhdr(ctx.data)
+    nh = ctx.data + 14
+    if nh + 20 > data_end:
+        return c_int64(XDP_DROP)
+    iph = iphdr(nh)
+    h_proto = eth.h_proto
+    h_proto_ext = c_int64(h_proto)
+    ipv4 = iph.saddr
+    print(f"ipaddress: {ipv4}")
+    return c_int64(XDP_PASS)
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile_to_ir("xdp_test_1.py", "xdp_test_1.ll")
+compile()