--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+#include <stdbool.h>
+#include <stdint.h>
+#include <linux/stddef.h>
+#include <linux/if_ether.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/bpf.h>
+#include <linux/types.h>
+#include <bpf/bpf_endian.h>
+#include <bpf/bpf_helpers.h>
+
+enum pkt_parse_err {
+ NO_ERR,
+ BAD_IP6_HDR,
+ BAD_IP4GUE_HDR,
+ BAD_IP6GUE_HDR,
+};
+
+enum pkt_flag {
+ TUNNEL = 0x1,
+ TCP_SYN = 0x2,
+ QUIC_INITIAL_FLAG = 0x4,
+ TCP_ACK = 0x8,
+ TCP_RST = 0x10
+};
+
+struct v4_lpm_key {
+ __u32 prefixlen;
+ __u32 src;
+};
+
+struct v4_lpm_val {
+ struct v4_lpm_key key;
+ __u8 val;
+};
+
+struct {
+ __uint(type, BPF_MAP_TYPE_HASH);
+ __uint(max_entries, 16);
+ __type(key, struct in6_addr);
+ __type(value, bool);
+} v6_addr_map SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_HASH);
+ __uint(max_entries, 16);
+ __type(key, __u32);
+ __type(value, bool);
+} v4_addr_map SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_LPM_TRIE);
+ __uint(max_entries, 16);
+ __uint(key_size, sizeof(struct v4_lpm_key));
+ __uint(value_size, sizeof(struct v4_lpm_val));
+ __uint(map_flags, BPF_F_NO_PREALLOC);
+} v4_lpm_val_map SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __uint(max_entries, 16);
+ __type(key, int);
+ __type(value, __u8);
+} tcp_port_map SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __uint(max_entries, 16);
+ __type(key, int);
+ __type(value, __u16);
+} udp_port_map SEC(".maps");
+
+enum ip_type { V4 = 1, V6 = 2 };
+
+struct fw_match_info {
+ __u8 v4_src_ip_match;
+ __u8 v6_src_ip_match;
+ __u8 v4_src_prefix_match;
+ __u8 v4_dst_prefix_match;
+ __u8 tcp_dp_match;
+ __u16 udp_sp_match;
+ __u16 udp_dp_match;
+ bool is_tcp;
+ bool is_tcp_syn;
+};
+
+struct pkt_info {
+ enum ip_type type;
+ union {
+ struct iphdr *ipv4;
+ struct ipv6hdr *ipv6;
+ } ip;
+ int sport;
+ int dport;
+ __u16 trans_hdr_offset;
+ __u8 proto;
+ __u8 flags;
+};
+
+static __always_inline struct ethhdr *parse_ethhdr(void *data, void *data_end)
+{
+ struct ethhdr *eth = data;
+
+ if (eth + 1 > data_end)
+ return NULL;
+
+ return eth;
+}
+
+static __always_inline __u8 filter_ipv6_addr(const struct in6_addr *ipv6addr)
+{
+ __u8 *leaf;
+
+ leaf = bpf_map_lookup_elem(&v6_addr_map, ipv6addr);
+
+ return leaf ? *leaf : 0;
+}
+
+static __always_inline __u8 filter_ipv4_addr(const __u32 ipaddr)
+{
+ __u8 *leaf;
+
+ leaf = bpf_map_lookup_elem(&v4_addr_map, &ipaddr);
+
+ return leaf ? *leaf : 0;
+}
+
+static __always_inline __u8 filter_ipv4_lpm(const __u32 ipaddr)
+{
+ struct v4_lpm_key v4_key = {};
+ struct v4_lpm_val *lpm_val;
+
+ v4_key.src = ipaddr;
+ v4_key.prefixlen = 32;
+
+ lpm_val = bpf_map_lookup_elem(&v4_lpm_val_map, &v4_key);
+
+ return lpm_val ? lpm_val->val : 0;
+}
+
+
+static __always_inline void
+filter_src_dst_ip(struct pkt_info* info, struct fw_match_info* match_info)
+{
+ if (info->type == V6) {
+ match_info->v6_src_ip_match =
+ filter_ipv6_addr(&info->ip.ipv6->saddr);
+ } else if (info->type == V4) {
+ match_info->v4_src_ip_match =
+ filter_ipv4_addr(info->ip.ipv4->saddr);
+ match_info->v4_src_prefix_match =
+ filter_ipv4_lpm(info->ip.ipv4->saddr);
+ match_info->v4_dst_prefix_match =
+ filter_ipv4_lpm(info->ip.ipv4->daddr);
+ }
+}
+
+static __always_inline void *
+get_transport_hdr(__u16 offset, void *data, void *data_end)
+{
+ if (offset > 255 || data + offset > data_end)
+ return NULL;
+
+ return data + offset;
+}
+
+static __always_inline bool tcphdr_only_contains_flag(struct tcphdr *tcp,
+ __u32 FLAG)
+{
+ return (tcp_flag_word(tcp) &
+ (TCP_FLAG_ACK | TCP_FLAG_RST | TCP_FLAG_SYN | TCP_FLAG_FIN)) == FLAG;
+}
+
+static __always_inline void set_tcp_flags(struct pkt_info *info,
+ struct tcphdr *tcp) {
+ if (tcphdr_only_contains_flag(tcp, TCP_FLAG_SYN))
+ info->flags |= TCP_SYN;
+ else if (tcphdr_only_contains_flag(tcp, TCP_FLAG_ACK))
+ info->flags |= TCP_ACK;
+ else if (tcphdr_only_contains_flag(tcp, TCP_FLAG_RST))
+ info->flags |= TCP_RST;
+}
+
+static __always_inline bool
+parse_tcp(struct pkt_info *info, void *transport_hdr, void *data_end)
+{
+ struct tcphdr *tcp = transport_hdr;
+
+ if (tcp + 1 > data_end)
+ return false;
+
+ info->sport = bpf_ntohs(tcp->source);
+ info->dport = bpf_ntohs(tcp->dest);
+ set_tcp_flags(info, tcp);
+
+ return true;
+}
+
+static __always_inline bool
+parse_udp(struct pkt_info *info, void *transport_hdr, void *data_end)
+{
+ struct udphdr *udp = transport_hdr;
+
+ if (udp + 1 > data_end)
+ return false;
+
+ info->sport = bpf_ntohs(udp->source);
+ info->dport = bpf_ntohs(udp->dest);
+
+ return true;
+}
+
+static __always_inline __u8 filter_tcp_port(int port)
+{
+ __u8 *leaf = bpf_map_lookup_elem(&tcp_port_map, &port);
+
+ return leaf ? *leaf : 0;
+}
+
+static __always_inline __u16 filter_udp_port(int port)
+{
+ __u16 *leaf = bpf_map_lookup_elem(&udp_port_map, &port);
+
+ return leaf ? *leaf : 0;
+}
+
+static __always_inline bool
+filter_transport_hdr(void *transport_hdr, void *data_end,
+ struct pkt_info *info, struct fw_match_info *match_info)
+{
+ if (info->proto == IPPROTO_TCP) {
+ if (!parse_tcp(info, transport_hdr, data_end))
+ return false;
+
+ match_info->is_tcp = true;
+ match_info->is_tcp_syn = (info->flags & TCP_SYN) > 0;
+
+ match_info->tcp_dp_match = filter_tcp_port(info->dport);
+ } else if (info->proto == IPPROTO_UDP) {
+ if (!parse_udp(info, transport_hdr, data_end))
+ return false;
+
+ match_info->udp_dp_match = filter_udp_port(info->dport);
+ match_info->udp_sp_match = filter_udp_port(info->sport);
+ }
+
+ return true;
+}
+
+static __always_inline __u8
+parse_gue_v6(struct pkt_info *info, struct ipv6hdr *ip6h, void *data_end)
+{
+ struct udphdr *udp = (struct udphdr *)(ip6h + 1);
+ void *encap_data = udp + 1;
+
+ if (udp + 1 > data_end)
+ return BAD_IP6_HDR;
+
+ if (udp->dest != bpf_htons(6666))
+ return NO_ERR;
+
+ info->flags |= TUNNEL;
+
+ if (encap_data + 1 > data_end)
+ return BAD_IP6GUE_HDR;
+
+ if (*(__u8 *)encap_data & 0x30) {
+ struct ipv6hdr *inner_ip6h = encap_data;
+
+ if (inner_ip6h + 1 > data_end)
+ return BAD_IP6GUE_HDR;
+
+ info->type = V6;
+ info->proto = inner_ip6h->nexthdr;
+ info->ip.ipv6 = inner_ip6h;
+ info->trans_hdr_offset += sizeof(struct ipv6hdr) + sizeof(struct udphdr);
+ } else {
+ struct iphdr *inner_ip4h = encap_data;
+
+ if (inner_ip4h + 1 > data_end)
+ return BAD_IP6GUE_HDR;
+
+ info->type = V4;
+ info->proto = inner_ip4h->protocol;
+ info->ip.ipv4 = inner_ip4h;
+ info->trans_hdr_offset += sizeof(struct iphdr) + sizeof(struct udphdr);
+ }
+
+ return NO_ERR;
+}
+
+static __always_inline __u8 parse_ipv6_gue(struct pkt_info *info,
+ void *data, void *data_end)
+{
+ struct ipv6hdr *ip6h = data + sizeof(struct ethhdr);
+
+ if (ip6h + 1 > data_end)
+ return BAD_IP6_HDR;
+
+ info->proto = ip6h->nexthdr;
+ info->ip.ipv6 = ip6h;
+ info->type = V6;
+ info->trans_hdr_offset = sizeof(struct ethhdr) + sizeof(struct ipv6hdr);
+
+ if (info->proto == IPPROTO_UDP)
+ return parse_gue_v6(info, ip6h, data_end);
+
+ return NO_ERR;
+}
+
+SEC("xdp")
+int edgewall(struct xdp_md *ctx)
+{
+ void *data_end = (void *)(long)(ctx->data_end);
+ void *data = (void *)(long)(ctx->data);
+ struct fw_match_info match_info = {};
+ struct pkt_info info = {};
+ __u8 parse_err = NO_ERR;
+ void *transport_hdr;
+ struct ethhdr *eth;
+ bool filter_res;
+ __u32 proto;
+
+ eth = parse_ethhdr(data, data_end);
+ if (!eth)
+ return XDP_DROP;
+
+ proto = eth->h_proto;
+ if (proto != bpf_htons(ETH_P_IPV6))
+ return XDP_DROP;
+
+ if (parse_ipv6_gue(&info, data, data_end))
+ return XDP_DROP;
+
+ if (info.proto == IPPROTO_ICMPV6)
+ return XDP_PASS;
+
+ if (info.proto != IPPROTO_TCP && info.proto != IPPROTO_UDP)
+ return XDP_DROP;
+
+ filter_src_dst_ip(&info, &match_info);
+
+ transport_hdr = get_transport_hdr(info.trans_hdr_offset, data,
+ data_end);
+ if (!transport_hdr)
+ return XDP_DROP;
+
+ filter_res = filter_transport_hdr(transport_hdr, data_end,
+ &info, &match_info);
+ if (!filter_res)
+ return XDP_DROP;
+
+ if (match_info.is_tcp && !match_info.is_tcp_syn)
+ return XDP_PASS;
+
+ return XDP_DROP;
+}
+
+char LICENSE[] SEC("license") = "GPL";
projects / users / willy / xarray.git / commitdiff