Satisfy BPF verifier with port swhich it can't prove are init'd values

[flowspec-xdp] / xdp.c

diff --git a/xdp.c b/xdp.c
index 113c4a3306d2ed7fc65b3161cfabfbf348b36690..a32f605d3c4219f8713dda28b83452f4a7ab8f03 100644 (file)
--- a/xdp.c
+++ b/xdp.c
@@ -149,7 +149,7 @@ static const int XDP_DROP = 1;
 static long drop_cnt_map[RULECNT + STATIC_RULE_CNT];
 #define INCREMENT_MATCH(reason) { drop_cnt_map[reason] += 1; drop_cnt_map[reason] += data_end - pktdata; }
 
-#else
+#else /* TEST */
 #include <linux/bpf.h>
 #include <bpf/bpf_helpers.h>
 
@@ -187,12 +187,42 @@ struct {
        __u32 *key;
        struct ratelimit *value;
 } rate_map SEC(".maps");
-#endif
+#endif /* RATE_CNT */
+
+// For per-source rate limiting, we have to use per-CPU hash maps as Linux
+// doesn't support spinlocks inside of a LRU_HASH (see if block in
+// map_check_btf as of Linux 5.10).
+// This isn't exactly accurate, but at least its faster.
+struct percpu_ratelimit {
+       union {
+               int64_t sent_bytes;
+               int64_t sent_packets;
+       } rate;
+       int64_t sent_time;
+};
+
+#define V6_SRC_RATE_DEFINE(n, limit) \
+struct { \
+       __uint(type, BPF_MAP_TYPE_LRU_PERCPU_HASH); \
+       __uint(max_entries, limit); \
+       uint128_t *key; \
+       struct percpu_ratelimit *value; \
+} v6_src_rate_##n SEC(".maps");
+
+#define V4_SRC_RATE_DEFINE(n, limit) \
+struct { \
+       __uint(type, BPF_MAP_TYPE_LRU_PERCPU_HASH); \
+       __uint(max_entries, limit); \
+       __u32 *key; \
+       struct percpu_ratelimit *value; \
+} v4_src_rate_##n SEC(".maps");
+
+#include "maps.h"
 
 #ifndef HAVE_WRAPPER // Set this to call xdp_drop externally
 SEC("xdp_drop")
-#endif
-#endif
+#endif /* HAVE_WRAPPER */
+#endif /* not TEST */
 int xdp_drop_prog(struct xdp_md *ctx)
 {
        const void *const data_end = (void *)(size_t)ctx->data_end;
@@ -235,7 +265,7 @@ int xdp_drop_prog(struct xdp_md *ctx)
        const void *l4hdr = NULL;
        const struct tcphdr *tcp = NULL;
        uint8_t ports_valid = 0;
-       uint16_t sport, dport; // Host Endian! Only valid with tcp || udp
+       uint16_t sport = 0, dport = 0; // Host Endian! Only valid with tcp || udp
 
 #ifdef NEED_V4_PARSE
        if (eth_proto == BE16(ETH_P_IP)) {