1 // SPDX-License-Identifier: GPL-2.0 2 3 /* 4 * Verify that consecutive sends over packet tx_ring are mirrored 5 * with their original content intact. 6 */ 7 8 #define _GNU_SOURCE 9 10 #include <arpa/inet.h> 11 #include <assert.h> 12 #include <error.h> 13 #include <errno.h> 14 #include <fcntl.h> 15 #include <linux/filter.h> 16 #include <linux/if_packet.h> 17 #include <net/ethernet.h> 18 #include <net/if.h> 19 #include <netinet/in.h> 20 #include <netinet/ip.h> 21 #include <netinet/udp.h> 22 #include <poll.h> 23 #include <pthread.h> 24 #include <sched.h> 25 #include <sys/ioctl.h> 26 #include <sys/mman.h> 27 #include <sys/socket.h> 28 #include <sys/time.h> 29 #include <sys/types.h> 30 #include <sys/utsname.h> 31 #include <stdbool.h> 32 #include <stdint.h> 33 #include <stdio.h> 34 #include <stdlib.h> 35 #include <string.h> 36 #include <unistd.h> 37 38 const int eth_off = TPACKET_HDRLEN - sizeof(struct sockaddr_ll); 39 const int cfg_frame_size = 1000; 40 41 static void build_packet(void *buffer, size_t blen, char payload_char) 42 { 43 struct udphdr *udph; 44 struct ethhdr *eth; 45 struct iphdr *iph; 46 size_t off = 0; 47 48 memset(buffer, 0, blen); 49 50 eth = buffer; 51 eth->h_proto = htons(ETH_P_IP); 52 53 off += sizeof(*eth); 54 iph = buffer + off; 55 iph->ttl = 8; 56 iph->ihl = 5; 57 iph->version = 4; 58 iph->saddr = htonl(INADDR_LOOPBACK); 59 iph->daddr = htonl(INADDR_LOOPBACK + 1); 60 iph->protocol = IPPROTO_UDP; 61 iph->tot_len = htons(blen - off); 62 iph->check = 0; 63 64 off += sizeof(*iph); 65 udph = buffer + off; 66 udph->dest = htons(8000); 67 udph->source = htons(8001); 68 udph->len = htons(blen - off); 69 udph->check = 0; 70 71 off += sizeof(*udph); 72 memset(buffer + off, payload_char, blen - off); 73 } 74 75 static int setup_rx(void) 76 { 77 int fdr; 78 79 fdr = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_IP)); 80 if (fdr == -1) 81 error(1, errno, "socket r"); 82 83 return fdr; 84 } 85 86 static int setup_tx(char **ring) 87 { 88 struct sockaddr_ll laddr = {}; 89 struct tpacket_req req = {}; 90 int fdt; 91 92 fdt = socket(PF_PACKET, SOCK_RAW, 0); 93 if (fdt == -1) 94 error(1, errno, "socket t"); 95 96 laddr.sll_family = AF_PACKET; 97 laddr.sll_protocol = htons(0); 98 laddr.sll_ifindex = if_nametoindex("lo"); 99 if (!laddr.sll_ifindex) 100 error(1, errno, "if_nametoindex"); 101 102 if (bind(fdt, (void *)&laddr, sizeof(laddr))) 103 error(1, errno, "bind fdt"); 104 105 req.tp_block_size = getpagesize(); 106 req.tp_block_nr = 1; 107 req.tp_frame_size = getpagesize(); 108 req.tp_frame_nr = 1; 109 110 if (setsockopt(fdt, SOL_PACKET, PACKET_TX_RING, 111 (void *)&req, sizeof(req))) 112 error(1, errno, "setsockopt ring"); 113 114 *ring = mmap(0, req.tp_block_size * req.tp_block_nr, 115 PROT_READ | PROT_WRITE, MAP_SHARED, fdt, 0); 116 if (*ring == MAP_FAILED) 117 error(1, errno, "mmap"); 118 119 return fdt; 120 } 121 122 static void send_pkt(int fdt, void *slot, char payload_char) 123 { 124 struct tpacket_hdr *header = slot; 125 int ret; 126 127 while (header->tp_status != TP_STATUS_AVAILABLE) 128 usleep(1000); 129 130 build_packet(slot + eth_off, cfg_frame_size, payload_char); 131 132 header->tp_len = cfg_frame_size; 133 header->tp_status = TP_STATUS_SEND_REQUEST; 134 135 ret = sendto(fdt, NULL, 0, 0, NULL, 0); 136 if (ret == -1) 137 error(1, errno, "kick tx"); 138 } 139 140 static int read_verify_pkt(int fdr, char payload_char) 141 { 142 char buf[100]; 143 int ret; 144 145 ret = read(fdr, buf, sizeof(buf)); 146 if (ret != sizeof(buf)) 147 error(1, errno, "read"); 148 149 if (buf[60] != payload_char) { 150 printf("wrong pattern: 0x%x != 0x%x\n", buf[60], payload_char); 151 return 1; 152 } 153 154 printf("read: %c (0x%x)\n", buf[60], buf[60]); 155 return 0; 156 } 157 158 int main(int argc, char **argv) 159 { 160 const char payload_patterns[] = "ab"; 161 char *ring; 162 int fdr, fdt, ret = 0; 163 164 fdr = setup_rx(); 165 fdt = setup_tx(&ring); 166 167 send_pkt(fdt, ring, payload_patterns[0]); 168 send_pkt(fdt, ring, payload_patterns[1]); 169 170 ret |= read_verify_pkt(fdr, payload_patterns[0]); 171 ret |= read_verify_pkt(fdr, payload_patterns[1]); 172 173 if (close(fdt)) 174 error(1, errno, "close t"); 175 if (close(fdr)) 176 error(1, errno, "close r"); 177 178 return ret; 179 } 180