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
38const int eth_off = TPACKET_HDRLEN - sizeof(struct sockaddr_ll);
39const int cfg_frame_size = 1000;
40
41static 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
75static 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
86static 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
122static 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
140static 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
158int 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