Drop ports_valid flag, it just wastes a register

[flowspec-xdp] / xdp.c

diff --git a/xdp.c b/xdp.c
index 113c4a3306d2ed7fc65b3161cfabfbf348b36690..75a44ff2a16d0a22a3cd462107feeec7dd3997c1 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;
@@ -234,8 +264,7 @@ 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
+       int32_t sport = -1, dport = -1; // Host Endian! Only valid with tcp || udp
 
 #ifdef NEED_V4_PARSE
        if (eth_proto == BE16(ETH_P_IP)) {
@@ -257,13 +286,11 @@ int xdp_drop_prog(struct xdp_md *ctx)
                                tcp = (struct tcphdr*) l4hdr;
                                sport = BE16(tcp->source);
                                dport = BE16(tcp->dest);
-                               ports_valid = 1;
                        } else if (ip->protocol == IP_PROTO_UDP) {
                                CHECK_LEN(l4hdr, udphdr);
                                const struct udphdr *udp = (struct udphdr*) l4hdr;
                                sport = BE16(udp->source);
                                dport = BE16(udp->dest);
-                               ports_valid = 1;
                        } else if (ip->protocol == IP_PROTO_ICMP) {
                                CHECK_LEN(l4hdr, icmphdr);
                                icmp = (struct icmphdr*) l4hdr;
@@ -304,13 +331,11 @@ int xdp_drop_prog(struct xdp_md *ctx)
                                tcp = (struct tcphdr*) l4hdr;
                                sport = BE16(tcp->source);
                                dport = BE16(tcp->dest);
-                               ports_valid = 1;
                        } else if (v6nexthdr == IP_PROTO_UDP) {
                                CHECK_LEN(l4hdr, udphdr);
                                const struct udphdr *udp = (struct udphdr*) l4hdr;
                                sport = BE16(udp->source);
                                dport = BE16(udp->dest);
-                               ports_valid = 1;
                        } else if (v6nexthdr == IP6_PROTO_ICMPV6) {
                                CHECK_LEN(l4hdr, icmp6hdr);
                                icmpv6 = (struct icmp6hdr*) l4hdr;