// Note that all operations on uint128s *stay* in Network byte order!
#if defined(__LITTLE_ENDIAN)
-#define BIGEND32(v) ((v >> 3*8) | ((v >> 8) & 0xff00) | ((v << 8) & 0xff0000) | (v << 3*8) & 0xff000000)
+#define BIGEND32(v) (((((uint32_t)(v)) >> 3*8) & 0xff) | \
+ ((((uint32_t)(v)) >> 1*8) & 0xff00) | \
+ ((((uint32_t)(v)) << 1*8) & 0xff0000) | \
+ ((((uint32_t)(v)) << 3*8) & 0xff000000))
#elif defined(__BIG_ENDIAN)
-#define BIGEND32(v) (v)
+#define BIGEND32(v) ((uint32_t)(v))
#else
#error "Need endian info"
#endif
(((uint128_t)BIGEND32(a)) << 0*32))
#define HTON128(a) BIGEND128(a >> 3*32, a >> 2*32, a >> 1*32, a>> 0*32)
// Yes, somehow macro'ing this changes LLVM's view of htons...
-#define BE16(a) ((((uint16_t)(a & 0xff00)) >> 8) | (((uint16_t)(a & 0xff)) << 8))
+#define BE16(a) (((((uint16_t)a) & 0xff00) >> 8) | ((((uint16_t)a) & 0xff) << 8))
#elif defined(__BIG_ENDIAN)
-#define BIGEND128(a, b, c, d) ((((uint128_t)a) << 3*32) | (((uint128_t)b) << 2*32) | (((uint128_t)c) << 1*32) | (((uint128_t)d) << 0*32))
-#define HTON128(a) (a)
+#define BIGEND128(a, b, c, d) ((((uint128_t)(a)) << 3*32) | (((uint128_t)(b)) << 2*32) | (((uint128_t)(c)) << 1*32) | (((uint128_t)(d)) << 0*32))
+#define HTON128(a) ((uint128_t)(a))
+#define BE16(a) ((uint16_t)(a))
#else
#error "Need endian info"
#endif
#define MASK6(pfxlen) HTON128(~((((uint128_t)1) << (128 - pfxlen)) - 1))
#define MASK6_OFFS(offs, pfxlen) HTON128((~((((uint128_t)1) << (128 - pfxlen)) - 1)) & ((((uint128_t)1) << (128 - offs)) - 1))
-// Note rules.h may also define PARSE_8021Q and REQ_8021Q
-// Note rules.h may also define PARSE_IHL
+// PARSE is used as a preprocessor flag to indicate parsing fields
+#define PARSE 42
#include "rules.h"
#define unlikely(a) __builtin_expect(a, 0)
#define likely(a) __builtin_expect(a, 1)
+static const uint32_t PKT_LEN_DROP = 0;
+static const uint32_t VLAN_DROP = 1;
+static const uint32_t IHL_DROP = 2;
+static const uint32_t V6FRAG_DROP = 3;
+#define STATIC_RULE_CNT 4
+
+#define DO_RETURN(reason, ret) {\
+ if (ret == XDP_DROP) { INCREMENT_MATCH(reason); } \
+ return ret; \
+ }
+
+// It seems (based on drop counts) that data_end points to the last byte, not one-past-the-end.
+// This feels strange, but some documentation suggests > here as well, so we stick with that.
+#define CHECK_LEN(start, struc) \
+ if (unlikely((void*)(start) + sizeof(struct struc) > data_end)) DO_RETURN(PKT_LEN_DROP, XDP_DROP);
+
#ifdef TEST
// 64 bit version of xdp_md for testing
struct xdp_md {
};
static const int XDP_PASS = 0;
static const int XDP_DROP = 1;
-#else
+
+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 /* TEST */
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
+struct match_counter {
+ uint64_t bytes;
+ uint64_t packets;
+};
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+ __uint(max_entries, RULECNT + STATIC_RULE_CNT);
+ __u32 *key;
+ struct match_counter *value;
+} drop_cnt_map SEC(".maps");
+
+#define INCREMENT_MATCH(reason) { \
+ struct match_counter *value = bpf_map_lookup_elem(&drop_cnt_map, &reason); \
+ if (value) { \
+ value->bytes += data_end - pktdata; \
+ value->packets += 1; \
+ } \
+}
+
+#ifdef RATE_CNT
+struct ratelimit {
+ struct bpf_spin_lock lock;
+ union {
+ int64_t sent_bytes;
+ int64_t sent_packets;
+ } rate;
+ int64_t sent_time;
+};
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __uint(max_entries, RATE_CNT);
+ __u32 *key;
+ struct ratelimit *value;
+} 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;
+};
+
+#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 /* HAVE_WRAPPER */
+#endif /* not TEST */
int xdp_drop_prog(struct xdp_md *ctx)
{
const void *const data_end = (void *)(size_t)ctx->data_end;
unsigned short eth_proto;
{
- if (unlikely((void*)(size_t)ctx->data + sizeof(struct ethhdr) > data_end))
- return XDP_DROP;
+ // DO_RETURN in CHECK_LEN relies on pktdata being set to calculate packet length.
+ // That said, we don't want to overflow, so just set packet length to 0 here.
+ pktdata = data_end;
+ CHECK_LEN((size_t)ctx->data, ethhdr);
const struct ethhdr *const eth = (void*)(size_t)ctx->data;
+ pktdata = (const void *)(long)ctx->data + sizeof(struct ethhdr);
-#ifdef PARSE_8021Q
+#if PARSE_8021Q == PARSE
if (likely(eth->h_proto == BE16(ETH_P_8021Q))) {
- if (unlikely((void*)(size_t)ctx->data + sizeof(struct ethhdr_vlan) > data_end))
- return XDP_DROP;
+ CHECK_LEN((size_t)ctx->data, ethhdr_vlan);
const struct ethhdr_vlan *const eth_vlan = (void*)(size_t)ctx->data;
-
+ pktdata = (const void *)(long)ctx->data + sizeof(struct ethhdr_vlan);
#ifdef REQ_8021Q
if (unlikely((eth_vlan->tci & BE16(0xfff)) != BE16(REQ_8021Q)))
- return XDP_DROP;
+ DO_RETURN(VLAN_DROP, XDP_DROP);
#endif
-
eth_proto = eth_vlan->h_proto;
+#else
+ if (unlikely(eth->h_proto == BE16(ETH_P_8021Q))) {
pktdata = (const void *)(long)ctx->data + sizeof(struct ethhdr_vlan);
+ DO_RETURN(VLAN_DROP, PARSE_8021Q);
+#endif
} else {
#ifdef REQ_8021Q
- return XDP_DROP;
+ DO_RETURN(VLAN_DROP, XDP_DROP);
#else
- pktdata = (const void *)(long)ctx->data + sizeof(struct ethhdr);
eth_proto = eth->h_proto;
#endif
}
-#else
- pktdata = (const void *)(long)ctx->data + sizeof(struct ethhdr);
- eth_proto = eth->h_proto;
-#endif
}
- const struct tcphdr *tcp = NULL;
- const struct udphdr *udp = NULL;
- const struct icmphdr *icmp = NULL;
- const struct icmp6hdr *icmpv6 = NULL;
- const struct ip6_fraghdr *frag6 = NULL;
- const struct iphdr *ip = NULL;
- const struct ip6hdr *ip6 = NULL;
const void *l4hdr = NULL;
+ const struct tcphdr *tcp = NULL;
+ uint8_t ports_valid = 0;
+ uint16_t sport = 0, dport = 0; // Host Endian! Only valid with tcp || udp
+
+#ifdef NEED_V4_PARSE
if (eth_proto == BE16(ETH_P_IP)) {
- if (unlikely(pktdata + sizeof(struct iphdr) > data_end))
- return XDP_DROP;
- ip = (struct iphdr*) pktdata;
+ CHECK_LEN(pktdata, iphdr);
+ struct iphdr *ip = (struct iphdr*) pktdata;
-#ifdef PARSE_IHL
- if (unlikely(ip->ihl < 5)) return XDP_DROP;
+#if PARSE_IHL == PARSE
+ if (unlikely(ip->ihl < 5)) DO_RETURN(IHL_DROP, XDP_DROP);
l4hdr = pktdata + ip->ihl * 4;
#else
- if (ip->ihl != 5) return XDP_DROP;
+ if (ip->ihl != 5) DO_RETURN(IHL_DROP, PARSE_IHL);
l4hdr = pktdata + 5*4;
#endif
- if (ip->protocol == IP_PROTO_TCP) {
- if (unlikely(l4hdr + sizeof(struct tcphdr) > data_end))
- return XDP_DROP;
- tcp = (struct tcphdr*) l4hdr;
- } else if (ip->protocol == IP_PROTO_UDP) {
- if (unlikely(l4hdr + sizeof(struct udphdr) > data_end))
- return XDP_DROP;
- udp = (struct udphdr*) l4hdr;
- } else if (ip->protocol == IP_PROTO_ICMP) {
- if (unlikely(l4hdr + sizeof(struct icmphdr) > data_end))
- return XDP_DROP;
- icmp = (struct icmphdr*) l4hdr;
+
+ const struct icmphdr *icmp = NULL;
+ if ((ip->frag_off & BE16(IP_OFFSET)) == 0) {
+ if (ip->protocol == IP_PROTO_TCP) {
+ CHECK_LEN(l4hdr, tcphdr);
+ 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;
+ }
}
- } else if (eth_proto == BE16(ETH_P_IPV6)) {
- if (unlikely(pktdata + sizeof(struct ip6hdr) > data_end))
- return XDP_DROP;
- ip6 = (struct ip6hdr*) pktdata;
+
+ RULES4
+ }
+#endif
+#ifdef NEED_V6_PARSE
+ if (eth_proto == BE16(ETH_P_IPV6)) {
+ CHECK_LEN(pktdata, ip6hdr);
+ struct ip6hdr *ip6 = (struct ip6hdr*) pktdata;
l4hdr = pktdata + 40;
- uint8_t v6nexthdr;
+ uint8_t v6nexthdr = ip6->nexthdr;
+ const struct ip6_fraghdr *frag6 = NULL;
+#ifdef PARSE_V6_FRAG
+#if PARSE_V6_FRAG == PARSE
if (ip6->nexthdr == IP6_PROTO_FRAG) {
- if (unlikely(l4hdr + sizeof(struct ip6_fraghdr) > data_end))
- return XDP_DROP;
+ CHECK_LEN(l4hdr, ip6_fraghdr);
frag6 = (struct ip6_fraghdr*) l4hdr;
l4hdr = l4hdr + sizeof(struct ip6_fraghdr);
v6nexthdr = frag6->nexthdr;
- } else {
- v6nexthdr = ip6->nexthdr;
+#else
+ if (unlikely(ip6->nexthdr == IP6_PROTO_FRAG)) {
+ DO_RETURN(V6FRAG_DROP, PARSE_V6_FRAG);
+#endif
}
-
- if (v6nexthdr == IP_PROTO_TCP) {
- if (unlikely(l4hdr + sizeof(struct tcphdr) > data_end))
- return XDP_DROP;
- tcp = (struct tcphdr*) l4hdr;
- } else if (v6nexthdr == IP_PROTO_UDP) {
- if (unlikely(l4hdr + sizeof(struct udphdr) > data_end))
- return XDP_DROP;
- udp = (struct udphdr*) l4hdr;
- } else if (v6nexthdr == IP6_PROTO_ICMPV6) {
- if (unlikely(l4hdr + sizeof(struct icmp6hdr) > data_end))
- return XDP_DROP;
- icmpv6 = (struct icmp6hdr*) l4hdr;
+#endif
+ // TODO: Handle more options?
+
+ const struct icmp6hdr *icmpv6 = NULL;
+ if (frag6 == NULL || (frag6->frag_off & BE16(IP6_FRAGOFF)) == 0) {
+ if (v6nexthdr == IP_PROTO_TCP) {
+ CHECK_LEN(l4hdr, tcphdr);
+ 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;
+ }
}
- // TODO: Handle some options?
- } else {
- return XDP_PASS;
- }
- uint16_t sport, dport; // Host Endian! Only valid with tcp || udp
- if (tcp != NULL) {
- sport = BE16(tcp->source);
- dport = BE16(tcp->dest);
- } else if (udp != NULL) {
- sport = BE16(udp->source);
- dport = BE16(udp->dest);
+ RULES6
}
-
- RULES
+#endif
return XDP_PASS;
}
#include <assert.h>
#include <string.h>
-const char d[] = TEST;
+char d[] = TEST;
int main() {
struct xdp_md test = {
.data = (uint64_t)d,
projects / flowspec-xdp / blobdiff