X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=xdp.c;h=a32f605d3c4219f8713dda28b83452f4a7ab8f03;hb=36cf3e162d8ca62a573f7b7989a9ec5b50ebba8c;hp=4e4d6c6308437ed759239c1f166f982dca36256c;hpb=a8be3b609743627f58a464d7b75217a778eb4fa9;p=flowspec-xdp diff --git a/xdp.c b/xdp.c index 4e4d6c6..a32f605 100644 --- a/xdp.c +++ b/xdp.c @@ -77,9 +77,12 @@ struct tcphdr { // 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 @@ -92,10 +95,11 @@ struct tcphdr { (((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 @@ -117,6 +121,16 @@ 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 { @@ -133,38 +147,82 @@ static const int XDP_PASS = 0; static const int XDP_DROP = 1; static long drop_cnt_map[RULECNT + STATIC_RULE_CNT]; -#define DO_RETURN(reason, ret) { \ - if (ret == XDP_DROP) drop_cnt_map[reason] += 1; \ - return ret; \ - } +#define INCREMENT_MATCH(reason) { drop_cnt_map[reason] += 1; drop_cnt_map[reason] += data_end - pktdata; } -#else +#else /* TEST */ #include #include -struct bpf_map_def SEC("maps") drop_cnt_map = { - .type = BPF_MAP_TYPE_PERCPU_ARRAY, - .key_size = sizeof(uint32_t), - .value_size = sizeof(long), - .max_entries = RULECNT + STATIC_RULE_CNT, +struct match_counter { + uint64_t bytes; + uint64_t packets; }; -#define DO_RETURN(reason, ret) {\ - if (ret == XDP_DROP) { \ - long *value = bpf_map_lookup_elem(&drop_cnt_map, &reason); \ - if (value) \ - *value += 1; \ - } \ - return XDP_DROP; \ - } - -SEC("xdp_drop") -#endif +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; \ + } \ +} -// 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 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 /* HAVE_WRAPPER */ +#endif /* not TEST */ int xdp_drop_prog(struct xdp_md *ctx) { const void *const data_end = (void *)(size_t)ctx->data_end; @@ -173,30 +231,32 @@ int xdp_drop_prog(struct xdp_md *ctx) unsigned short eth_proto; { + // 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); #if PARSE_8021Q == PARSE if (likely(eth->h_proto == BE16(ETH_P_8021Q))) { 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))) DO_RETURN(VLAN_DROP, XDP_DROP); #endif - eth_proto = eth_vlan->h_proto; - pktdata = (const void *)(long)ctx->data + sizeof(struct ethhdr_vlan); #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 DO_RETURN(VLAN_DROP, XDP_DROP); #else - pktdata = (const void *)(long)ctx->data + sizeof(struct ethhdr); eth_proto = eth->h_proto; #endif } @@ -205,12 +265,12 @@ 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)) { CHECK_LEN(pktdata, iphdr); - const struct iphdr *ip = (struct iphdr*) pktdata; + struct iphdr *ip = (struct iphdr*) pktdata; #if PARSE_IHL == PARSE if (unlikely(ip->ihl < 5)) DO_RETURN(IHL_DROP, XDP_DROP); @@ -246,7 +306,7 @@ int xdp_drop_prog(struct xdp_md *ctx) #ifdef NEED_V6_PARSE if (eth_proto == BE16(ETH_P_IPV6)) { CHECK_LEN(pktdata, ip6hdr); - const struct ip6hdr *ip6 = (struct ip6hdr*) pktdata; + struct ip6hdr *ip6 = (struct ip6hdr*) pktdata; l4hdr = pktdata + 40; @@ -298,7 +358,7 @@ int xdp_drop_prog(struct xdp_md *ctx) #include #include -const char d[] = TEST; +char d[] = TEST; int main() { struct xdp_md test = { .data = (uint64_t)d,