1// SPDX-License-Identifier: GPL-2.0
2
3#define _GNU_SOURCE
4
5#include <errno.h>
6#include <fcntl.h>
7#include <stdio.h>
8#include <stdlib.h>
9#include <string.h>
10#include <unistd.h>
11#include <net/if.h>
12#include <linux/if_tun.h>
13#include <linux/netlink.h>
14#include <linux/rtnetlink.h>
15#include <sys/ioctl.h>
16#include <sys/socket.h>
17#include <linux/virtio_net.h>
18#include <netinet/ip.h>
19#include <netinet/udp.h>
20#include "../kselftest_harness.h"
21
22static const char param_dev_tap_name[] = "xmacvtap0";
23static const char param_dev_dummy_name[] = "xdummy0";
24static unsigned char param_hwaddr_src[] = { 0x00, 0xfe, 0x98, 0x14, 0x22, 0x42 };
25static unsigned char param_hwaddr_dest[] = {
26 0x00, 0xfe, 0x98, 0x94, 0xd2, 0x43
27};
28
29#define MAX_RTNL_PAYLOAD (2048)
30#define PKT_DATA 0xCB
31#define TEST_PACKET_SZ (sizeof(struct virtio_net_hdr) + ETH_HLEN + ETH_MAX_MTU)
32
33static struct rtattr *rtattr_add(struct nlmsghdr *nh, unsigned short type,
34 unsigned short len)
35{
36 struct rtattr *rta =
37 (struct rtattr *)((uint8_t *)nh + RTA_ALIGN(nh->nlmsg_len));
38 rta->rta_type = type;
39 rta->rta_len = RTA_LENGTH(len);
40 nh->nlmsg_len = RTA_ALIGN(nh->nlmsg_len) + RTA_ALIGN(rta->rta_len);
41 return rta;
42}
43
44static struct rtattr *rtattr_begin(struct nlmsghdr *nh, unsigned short type)
45{
46 return rtattr_add(nh, type, len: 0);
47}
48
49static void rtattr_end(struct nlmsghdr *nh, struct rtattr *attr)
50{
51 uint8_t *end = (uint8_t *)nh + nh->nlmsg_len;
52
53 attr->rta_len = end - (uint8_t *)attr;
54}
55
56static struct rtattr *rtattr_add_str(struct nlmsghdr *nh, unsigned short type,
57 const char *s)
58{
59 struct rtattr *rta = rtattr_add(nh, type, strlen(s));
60
61 memcpy(RTA_DATA(rta), s, strlen(s));
62 return rta;
63}
64
65static struct rtattr *rtattr_add_strsz(struct nlmsghdr *nh, unsigned short type,
66 const char *s)
67{
68 struct rtattr *rta = rtattr_add(nh, type, strlen(s) + 1);
69
70 strcpy(RTA_DATA(rta), q: s);
71 return rta;
72}
73
74static struct rtattr *rtattr_add_any(struct nlmsghdr *nh, unsigned short type,
75 const void *arr, size_t len)
76{
77 struct rtattr *rta = rtattr_add(nh, type, len);
78
79 memcpy(RTA_DATA(rta), arr, len);
80 return rta;
81}
82
83static int dev_create(const char *dev, const char *link_type,
84 int (*fill_rtattr)(struct nlmsghdr *nh),
85 int (*fill_info_data)(struct nlmsghdr *nh))
86{
87 struct {
88 struct nlmsghdr nh;
89 struct ifinfomsg info;
90 unsigned char data[MAX_RTNL_PAYLOAD];
91 } req;
92 struct rtattr *link_info, *info_data;
93 int ret, rtnl;
94
95 rtnl = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
96 if (rtnl < 0) {
97 fprintf(stderr, "%s: socket %s\n", __func__, strerror(errno));
98 return 1;
99 }
100
101 memset(&req, 0, sizeof(req));
102 req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.info));
103 req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE;
104 req.nh.nlmsg_type = RTM_NEWLINK;
105
106 req.info.ifi_family = AF_UNSPEC;
107 req.info.ifi_type = 1;
108 req.info.ifi_index = 0;
109 req.info.ifi_flags = IFF_BROADCAST | IFF_UP;
110 req.info.ifi_change = 0xffffffff;
111
112 rtattr_add_str(nh: &req.nh, type: IFLA_IFNAME, s: dev);
113
114 if (fill_rtattr) {
115 ret = fill_rtattr(&req.nh);
116 if (ret)
117 return ret;
118 }
119
120 link_info = rtattr_begin(nh: &req.nh, IFLA_LINKINFO);
121
122 rtattr_add_strsz(nh: &req.nh, type: IFLA_INFO_KIND, s: link_type);
123
124 if (fill_info_data) {
125 info_data = rtattr_begin(nh: &req.nh, type: IFLA_INFO_DATA);
126 ret = fill_info_data(&req.nh);
127 if (ret)
128 return ret;
129 rtattr_end(nh: &req.nh, attr: info_data);
130 }
131
132 rtattr_end(nh: &req.nh, attr: link_info);
133
134 ret = send(rtnl, &req, req.nh.nlmsg_len, 0);
135 if (ret < 0)
136 fprintf(stderr, "%s: send %s\n", __func__, strerror(errno));
137 ret = (unsigned int)ret != req.nh.nlmsg_len;
138
139 close(rtnl);
140 return ret;
141}
142
143static int dev_delete(const char *dev)
144{
145 struct {
146 struct nlmsghdr nh;
147 struct ifinfomsg info;
148 unsigned char data[MAX_RTNL_PAYLOAD];
149 } req;
150 int ret, rtnl;
151
152 rtnl = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
153 if (rtnl < 0) {
154 fprintf(stderr, "%s: socket %s\n", __func__, strerror(errno));
155 return 1;
156 }
157
158 memset(&req, 0, sizeof(req));
159 req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.info));
160 req.nh.nlmsg_flags = NLM_F_REQUEST;
161 req.nh.nlmsg_type = RTM_DELLINK;
162
163 req.info.ifi_family = AF_UNSPEC;
164
165 rtattr_add_str(nh: &req.nh, type: IFLA_IFNAME, s: dev);
166
167 ret = send(rtnl, &req, req.nh.nlmsg_len, 0);
168 if (ret < 0)
169 fprintf(stderr, "%s: send %s\n", __func__, strerror(errno));
170
171 ret = (unsigned int)ret != req.nh.nlmsg_len;
172
173 close(rtnl);
174 return ret;
175}
176
177static int macvtap_fill_rtattr(struct nlmsghdr *nh)
178{
179 int ifindex;
180
181 ifindex = if_nametoindex(param_dev_dummy_name);
182 if (ifindex == 0) {
183 fprintf(stderr, "%s: ifindex %s\n", __func__, strerror(errno));
184 return -errno;
185 }
186
187 rtattr_add_any(nh, type: IFLA_LINK, arr: &ifindex, len: sizeof(ifindex));
188 rtattr_add_any(nh, type: IFLA_ADDRESS, arr: param_hwaddr_src, ETH_ALEN);
189
190 return 0;
191}
192
193static int opentap(const char *devname)
194{
195 int ifindex;
196 char buf[256];
197 int fd;
198 struct ifreq ifr;
199
200 ifindex = if_nametoindex(devname);
201 if (ifindex == 0) {
202 fprintf(stderr, "%s: ifindex %s\n", __func__, strerror(errno));
203 return -errno;
204 }
205
206 sprintf(buf, fmt: "/dev/tap%d", ifindex);
207 fd = open(buf, O_RDWR | O_NONBLOCK);
208 if (fd < 0) {
209 fprintf(stderr, "%s: open %s\n", __func__, strerror(errno));
210 return -errno;
211 }
212
213 memset(&ifr, 0, sizeof(ifr));
214 strcpy(p: ifr.ifr_name, q: devname);
215 ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_VNET_HDR | IFF_MULTI_QUEUE;
216 if (ioctl(fd, TUNSETIFF, &ifr, sizeof(ifr)) < 0)
217 return -errno;
218 return fd;
219}
220
221size_t build_eth(uint8_t *buf, uint16_t proto)
222{
223 struct ethhdr *eth = (struct ethhdr *)buf;
224
225 eth->h_proto = htons(proto);
226 memcpy(eth->h_source, param_hwaddr_src, ETH_ALEN);
227 memcpy(eth->h_dest, param_hwaddr_dest, ETH_ALEN);
228
229 return ETH_HLEN;
230}
231
232static uint32_t add_csum(const uint8_t *buf, int len)
233{
234 uint32_t sum = 0;
235 uint16_t *sbuf = (uint16_t *)buf;
236
237 while (len > 1) {
238 sum += *sbuf++;
239 len -= 2;
240 }
241
242 if (len)
243 sum += *(uint8_t *)sbuf;
244
245 return sum;
246}
247
248static uint16_t finish_ip_csum(uint32_t sum)
249{
250 uint16_t lo = sum & 0xffff;
251 uint16_t hi = sum >> 16;
252
253 return ~(lo + hi);
254
255}
256
257static uint16_t build_ip_csum(const uint8_t *buf, int len,
258 uint32_t sum)
259{
260 sum += add_csum(buf, len);
261 return finish_ip_csum(sum);
262}
263
264static int build_ipv4_header(uint8_t *buf, int payload_len)
265{
266 struct iphdr *iph = (struct iphdr *)buf;
267
268 iph->ihl = 5;
269 iph->version = 4;
270 iph->ttl = 8;
271 iph->tot_len =
272 htons(sizeof(*iph) + sizeof(struct udphdr) + payload_len);
273 iph->id = htons(1337);
274 iph->protocol = IPPROTO_UDP;
275 iph->saddr = htonl((172 << 24) | (17 << 16) | 2);
276 iph->daddr = htonl((172 << 24) | (17 << 16) | 1);
277 iph->check = build_ip_csum(buf, len: iph->ihl << 2, sum: 0);
278
279 return iph->ihl << 2;
280}
281
282static int build_udp_packet(uint8_t *buf, int payload_len, bool csum_off)
283{
284 const int ip4alen = sizeof(uint32_t);
285 struct udphdr *udph = (struct udphdr *)buf;
286 int len = sizeof(*udph) + payload_len;
287 uint32_t sum = 0;
288
289 udph->source = htons(22);
290 udph->dest = htons(58822);
291 udph->len = htons(len);
292
293 memset(buf + sizeof(struct udphdr), PKT_DATA, payload_len);
294
295 sum = add_csum(buf: buf - 2 * ip4alen, len: 2 * ip4alen);
296 sum += htons(IPPROTO_UDP) + udph->len;
297
298 if (!csum_off)
299 sum += add_csum(buf, len);
300
301 udph->check = finish_ip_csum(sum);
302
303 return sizeof(*udph) + payload_len;
304}
305
306size_t build_test_packet_valid_udp_gso(uint8_t *buf, size_t payload_len)
307{
308 uint8_t *cur = buf;
309 struct virtio_net_hdr *vh = (struct virtio_net_hdr *)buf;
310
311 vh->hdr_len = ETH_HLEN + sizeof(struct iphdr) + sizeof(struct udphdr);
312 vh->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
313 vh->csum_start = ETH_HLEN + sizeof(struct iphdr);
314 vh->csum_offset = __builtin_offsetof(struct udphdr, check);
315 vh->gso_type = VIRTIO_NET_HDR_GSO_UDP;
316 vh->gso_size = ETH_DATA_LEN - sizeof(struct iphdr);
317 cur += sizeof(*vh);
318
319 cur += build_eth(buf: cur, ETH_P_IP);
320 cur += build_ipv4_header(buf: cur, payload_len);
321 cur += build_udp_packet(buf: cur, payload_len, csum_off: true);
322
323 return cur - buf;
324}
325
326size_t build_test_packet_valid_udp_csum(uint8_t *buf, size_t payload_len)
327{
328 uint8_t *cur = buf;
329 struct virtio_net_hdr *vh = (struct virtio_net_hdr *)buf;
330
331 vh->flags = VIRTIO_NET_HDR_F_DATA_VALID;
332 vh->gso_type = VIRTIO_NET_HDR_GSO_NONE;
333 cur += sizeof(*vh);
334
335 cur += build_eth(buf: cur, ETH_P_IP);
336 cur += build_ipv4_header(buf: cur, payload_len);
337 cur += build_udp_packet(buf: cur, payload_len, csum_off: false);
338
339 return cur - buf;
340}
341
342size_t build_test_packet_crash_tap_invalid_eth_proto(uint8_t *buf,
343 size_t payload_len)
344{
345 uint8_t *cur = buf;
346 struct virtio_net_hdr *vh = (struct virtio_net_hdr *)buf;
347
348 vh->hdr_len = ETH_HLEN + sizeof(struct iphdr) + sizeof(struct udphdr);
349 vh->flags = 0;
350 vh->gso_type = VIRTIO_NET_HDR_GSO_UDP;
351 vh->gso_size = ETH_DATA_LEN - sizeof(struct iphdr);
352 cur += sizeof(*vh);
353
354 cur += build_eth(buf: cur, proto: 0);
355 cur += sizeof(struct iphdr) + sizeof(struct udphdr);
356 cur += build_ipv4_header(buf: cur, payload_len);
357 cur += build_udp_packet(buf: cur, payload_len, csum_off: true);
358 cur += payload_len;
359
360 return cur - buf;
361}
362
363FIXTURE(tap)
364{
365 int fd;
366};
367
368FIXTURE_SETUP(tap)
369{
370 int ret;
371
372 ret = dev_create(dev: param_dev_dummy_name, link_type: "dummy", NULL, NULL);
373 EXPECT_EQ(ret, 0);
374
375 ret = dev_create(dev: param_dev_tap_name, link_type: "macvtap", fill_rtattr: macvtap_fill_rtattr,
376 NULL);
377 EXPECT_EQ(ret, 0);
378
379 self->fd = opentap(devname: param_dev_tap_name);
380 ASSERT_GE(self->fd, 0);
381}
382
383FIXTURE_TEARDOWN(tap)
384{
385 int ret;
386
387 if (self->fd != -1)
388 close(self->fd);
389
390 ret = dev_delete(dev: param_dev_tap_name);
391 EXPECT_EQ(ret, 0);
392
393 ret = dev_delete(dev: param_dev_dummy_name);
394 EXPECT_EQ(ret, 0);
395}
396
397TEST_F(tap, test_packet_valid_udp_gso)
398{
399 uint8_t pkt[TEST_PACKET_SZ];
400 size_t off;
401 int ret;
402
403 memset(pkt, 0, sizeof(pkt));
404 off = build_test_packet_valid_udp_gso(buf: pkt, payload_len: 1021);
405 ret = write(self->fd, pkt, off);
406 ASSERT_EQ(ret, off);
407}
408
409TEST_F(tap, test_packet_valid_udp_csum)
410{
411 uint8_t pkt[TEST_PACKET_SZ];
412 size_t off;
413 int ret;
414
415 memset(pkt, 0, sizeof(pkt));
416 off = build_test_packet_valid_udp_csum(buf: pkt, payload_len: 1024);
417 ret = write(self->fd, pkt, off);
418 ASSERT_EQ(ret, off);
419}
420
421TEST_F(tap, test_packet_crash_tap_invalid_eth_proto)
422{
423 uint8_t pkt[TEST_PACKET_SZ];
424 size_t off;
425 int ret;
426
427 memset(pkt, 0, sizeof(pkt));
428 off = build_test_packet_crash_tap_invalid_eth_proto(buf: pkt, payload_len: 1024);
429 ret = write(self->fd, pkt, off);
430 ASSERT_EQ(ret, -1);
431 ASSERT_EQ(errno, EINVAL);
432}
433
434TEST_HARNESS_MAIN
435

source code of linux/tools/testing/selftests/net/tap.c