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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 | // SPDX-License-Identifier: GPL-2.0 /* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. */ #define KBUILD_MODNAME "foo" #include <stddef.h> #include <string.h> #include <linux/bpf.h> #include <linux/icmp.h> #include <linux/in.h> #include <linux/if_ether.h> #include <linux/if_packet.h> #include <linux/if_vlan.h> #include <linux/ip.h> #include <bpf/bpf_helpers.h> #include <bpf/bpf_endian.h> #include "bpf_compiler.h" #include "xdping.h" struct { __uint(type, BPF_MAP_TYPE_HASH); __uint(max_entries, 256); __type(key, __u32); __type(value, struct pinginfo); } ping_map SEC(".maps"); static __always_inline void swap_src_dst_mac(void *data) { unsigned short *p = data; unsigned short dst[3]; dst[0] = p[0]; dst[1] = p[1]; dst[2] = p[2]; p[0] = p[3]; p[1] = p[4]; p[2] = p[5]; p[3] = dst[0]; p[4] = dst[1]; p[5] = dst[2]; } static __always_inline __u16 csum_fold_helper(__wsum sum) { sum = (sum & 0xffff) + (sum >> 16); return ~((sum & 0xffff) + (sum >> 16)); } static __always_inline __u16 ipv4_csum(void *data_start, int data_size) { __wsum sum; sum = bpf_csum_diff(0, 0, data_start, data_size, 0); return csum_fold_helper(sum); } #define ICMP_ECHO_LEN 64 static __always_inline int icmp_check(struct xdp_md *ctx, int type) { void *data_end = (void *)(long)ctx->data_end; void *data = (void *)(long)ctx->data; struct ethhdr *eth = data; struct icmphdr *icmph; struct iphdr *iph; if (data + sizeof(*eth) + sizeof(*iph) + ICMP_ECHO_LEN > data_end) return XDP_PASS; if (eth->h_proto != bpf_htons(ETH_P_IP)) return XDP_PASS; iph = data + sizeof(*eth); if (iph->protocol != IPPROTO_ICMP) return XDP_PASS; if (bpf_ntohs(iph->tot_len) - sizeof(*iph) != ICMP_ECHO_LEN) return XDP_PASS; icmph = data + sizeof(*eth) + sizeof(*iph); if (icmph->type != type) return XDP_PASS; return XDP_TX; } SEC("xdp") int xdping_client(struct xdp_md *ctx) { void *data = (void *)(long)ctx->data; struct pinginfo *pinginfo = NULL; struct ethhdr *eth = data; struct icmphdr *icmph; struct iphdr *iph; __u64 recvtime; __be32 raddr; __be16 seq; int ret; __u8 i; ret = icmp_check(ctx, ICMP_ECHOREPLY); if (ret != XDP_TX) return ret; iph = data + sizeof(*eth); icmph = data + sizeof(*eth) + sizeof(*iph); raddr = iph->saddr; /* Record time reply received. */ recvtime = bpf_ktime_get_ns(); pinginfo = bpf_map_lookup_elem(&ping_map, &raddr); if (!pinginfo || pinginfo->seq != icmph->un.echo.sequence) return XDP_PASS; if (pinginfo->start) { __pragma_loop_unroll_full for (i = 0; i < XDPING_MAX_COUNT; i++) { if (pinginfo->times[i] == 0) break; } /* verifier is fussy here... */ if (i < XDPING_MAX_COUNT) { pinginfo->times[i] = recvtime - pinginfo->start; pinginfo->start = 0; i++; } /* No more space for values? */ if (i == pinginfo->count || i == XDPING_MAX_COUNT) return XDP_PASS; } /* Now convert reply back into echo request. */ swap_src_dst_mac(data); iph->saddr = iph->daddr; iph->daddr = raddr; icmph->type = ICMP_ECHO; seq = bpf_htons(bpf_ntohs(icmph->un.echo.sequence) + 1); icmph->un.echo.sequence = seq; icmph->checksum = 0; icmph->checksum = ipv4_csum(icmph, ICMP_ECHO_LEN); pinginfo->seq = seq; pinginfo->start = bpf_ktime_get_ns(); return XDP_TX; } SEC("xdp") int xdping_server(struct xdp_md *ctx) { void *data = (void *)(long)ctx->data; struct ethhdr *eth = data; struct icmphdr *icmph; struct iphdr *iph; __be32 raddr; int ret; ret = icmp_check(ctx, ICMP_ECHO); if (ret != XDP_TX) return ret; iph = data + sizeof(*eth); icmph = data + sizeof(*eth) + sizeof(*iph); raddr = iph->saddr; /* Now convert request into echo reply. */ swap_src_dst_mac(data); iph->saddr = iph->daddr; iph->daddr = raddr; icmph->type = ICMP_ECHOREPLY; icmph->checksum = 0; icmph->checksum = ipv4_csum(icmph, ICMP_ECHO_LEN); return XDP_TX; } char _license[] SEC("license") = "GPL"; |