#include <linux/icmpv6.h>
#include <arpa/inet.h>
-#define NULL (void*)0
+#include "siphash.h"
/* IP flags. */
#define IP_CE 0x8000 /* Flag: "Congestion" */
#ifdef RATE_CNT
struct ratelimit {
struct bpf_spin_lock lock;
- union {
- int64_t sent_bytes;
- int64_t sent_packets;
- } rate;
+ int64_t sent_rate;
int64_t sent_time;
};
struct {
} rate_map SEC(".maps");
#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;
-};
+// We implement a rather naive hashtable here instead of using a BPF map because
+// (a) the BPF map hashtables are similarly naive (no rehashing, etc),
+// (b) the BPF map LRU hashtables don't support locking.
+//
+// We first separate into a few top-level buckets with per-bucket locks, limiting
+// us to 2^SRC_HASH_MAX_PARALLELISM parallel accessors.
+//
+// Then we build an array of MAX_ENTRIES/2**SRC_HASH_MAX_PARALLELISM_POW entries,
+// which are split into buckets of size SRC_HASH_BUCKET_COUNT. An entry can appear
+// in any of the SRC_HASH_BUCKET_COUNT buckets at it's hash value.
+#define SRC_HASH_MAX_PARALLELISM_POW 9
+#define SRC_HASH_MAX_PARALLELISM (1 << SRC_HASH_MAX_PARALLELISM_POW)
+#define SRC_HASH_BUCKET_COUNT_POW 3
+#define SRC_HASH_BUCKET_COUNT (1 << SRC_HASH_BUCKET_COUNT_POW)
+
+#include "rand.h"
+
+#define CREATE_PERSRC_LOOKUP(IPV, IP_TYPE) \
+struct persrc_rate##IPV##_entry { \
+ int64_t sent_rate; \
+ int64_t sent_time; \
+ IP_TYPE srcip; \
+}; \
+ \
+struct persrc_rate##IPV##_bucket { \
+ struct bpf_spin_lock lock; \
+ struct persrc_rate##IPV##_entry entries[]; \
+}; \
+ \
+struct persrc_rate##IPV##_ptr { \
+ struct persrc_rate##IPV##_entry *rate; \
+ struct bpf_spin_lock *lock; \
+}; \
+ \
+__attribute__((always_inline)) \
+static inline struct persrc_rate##IPV##_ptr get_v##IPV##_persrc_ratelimit(IP_TYPE key, void *map, size_t map_limit) { \
+ struct persrc_rate##IPV##_ptr res = { .rate = NULL, .lock = NULL }; \
+ uint64_t hash = siphash(&key, sizeof(key), COMPILE_TIME_RAND); \
+ \
+ const uint32_t map_key = hash % SRC_HASH_MAX_PARALLELISM; \
+ struct persrc_rate##IPV##_bucket *buckets = bpf_map_lookup_elem(map, &map_key); \
+ if (!buckets) return res; \
+ \
+ hash >>= SRC_HASH_MAX_PARALLELISM_POW; \
+ map_limit >>= SRC_HASH_MAX_PARALLELISM_POW; \
+ \
+ struct persrc_rate##IPV##_entry *first_bucket = &buckets->entries[(hash % map_limit) & (~(SRC_HASH_BUCKET_COUNT - 1))]; \
+ bpf_spin_lock(&buckets->lock); \
+ \
+ int min_sent_idx = 0; \
+ int64_t min_sent_time = INT64_MAX; \
+ for (int i = 0; i < SRC_HASH_BUCKET_COUNT; i++) { \
+ if (first_bucket[i].srcip == key) { \
+ res.rate = &first_bucket[i]; \
+ res.lock = &buckets->lock; \
+ return res; \
+ } else if (min_sent_time > first_bucket[i].sent_time) { \
+ min_sent_time = first_bucket[i].sent_time; \
+ min_sent_idx = i; \
+ } \
+ } \
+ res.rate = &first_bucket[min_sent_idx]; \
+ res.rate->srcip = key; \
+ res.rate->sent_rate = 0; \
+ res.rate->sent_time = 0; \
+ res.lock = &buckets->lock; \
+ return res; \
+}
-#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");
+CREATE_PERSRC_LOOKUP(6, uint128_t)
+CREATE_PERSRC_LOOKUP(4, uint32_t)
-#define V4_SRC_RATE_DEFINE(n, limit) \
+#define SRC_RATE_DEFINE(IPV, n, limit) \
+struct persrc_rate##IPV##_bucket_##n { \
+ struct bpf_spin_lock lock; \
+ struct persrc_rate##IPV##_entry entries[limit / SRC_HASH_MAX_PARALLELISM]; \
+}; \
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");
+ __uint(type, BPF_MAP_TYPE_ARRAY); \
+ __uint(max_entries, SRC_HASH_MAX_PARALLELISM); \
+ uint32_t *key; \
+ struct persrc_rate##IPV##_bucket_##n *value; \
+} v##IPV##_src_rate_##n SEC(".maps");
#include "maps.h"
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)) {
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;
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;
projects / flowspec-xdp / blobdiff