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 
build_packet(void * buffer,size_t blen,char payload_char)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 
setup_rx(void)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 
setup_tx(char ** ring)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 
send_pkt(int fdt,void * slot,char payload_char)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 
read_verify_pkt(int fdr,char payload_char)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 
main(int argc,char ** argv)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