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
22 static const char param_dev_tap_name[] = "xmacvtap0";
23 static const char param_dev_dummy_name[] = "xdummy0";
24 static unsigned char param_hwaddr_src[] = { 0x00, 0xfe, 0x98, 0x14, 0x22, 0x42 };
25 static 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
33 static 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
44 static struct rtattr *rtattr_begin(struct nlmsghdr *nh, unsigned short type)
45 {
46 return rtattr_add(nh, type, 0);
47 }
48
49 static 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
56 static 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
65 static 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), s);
71 return rta;
72 }
73
74 static 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
83 static 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(&req.nh, IFLA_IFNAME, 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(&req.nh, IFLA_LINKINFO);
121
122 rtattr_add_strsz(&req.nh, IFLA_INFO_KIND, link_type);
123
124 if (fill_info_data) {
125 info_data = rtattr_begin(&req.nh, IFLA_INFO_DATA);
126 ret = fill_info_data(&req.nh);
127 if (ret)
128 return ret;
129 rtattr_end(&req.nh, info_data);
130 }
131
132 rtattr_end(&req.nh, 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
143 static 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(&req.nh, IFLA_IFNAME, 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
177 static 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, IFLA_LINK, &ifindex, sizeof(ifindex));
188 rtattr_add_any(nh, IFLA_ADDRESS, param_hwaddr_src, ETH_ALEN);
189
190 return 0;
191 }
192
193 static 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, "/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(ifr.ifr_name, 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
221 size_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
232 static 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
248 static 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
257 static 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
264 static 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, iph->ihl << 2, 0);
278
279 return iph->ihl << 2;
280 }
281
282 static 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 - 2 * ip4alen, 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
306 size_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(cur, ETH_P_IP);
320 cur += build_ipv4_header(cur, payload_len);
321 cur += build_udp_packet(cur, payload_len, true);
322
323 return cur - buf;
324 }
325
326 size_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(cur, ETH_P_IP);
336 cur += build_ipv4_header(cur, payload_len);
337 cur += build_udp_packet(cur, payload_len, false);
338
339 return cur - buf;
340 }
341
342 size_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(cur, 0);
355 cur += sizeof(struct iphdr) + sizeof(struct udphdr);
356 cur += build_ipv4_header(cur, payload_len);
357 cur += build_udp_packet(cur, payload_len, true);
358 cur += payload_len;
359
360 return cur - buf;
361 }
362
363 FIXTURE(tap)
364 {
365 int fd;
366 };
367
368 FIXTURE_SETUP(tap)
369 {
370 int ret;
371
372 ret = dev_create(param_dev_dummy_name, "dummy", NULL, NULL);
373 EXPECT_EQ(ret, 0);
374
375 ret = dev_create(param_dev_tap_name, "macvtap", macvtap_fill_rtattr,
376 NULL);
377 EXPECT_EQ(ret, 0);
378
379 self->fd = opentap(param_dev_tap_name);
380 ASSERT_GE(self->fd, 0);
381 }
382
383 FIXTURE_TEARDOWN(tap)
384 {
385 int ret;
386
387 if (self->fd != -1)
388 close(self->fd);
389
390 ret = dev_delete(param_dev_tap_name);
391 EXPECT_EQ(ret, 0);
392
393 ret = dev_delete(param_dev_dummy_name);
394 EXPECT_EQ(ret, 0);
395 }
396
397 TEST_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(pkt, 1021);
405 ret = write(self->fd, pkt, off);
406 ASSERT_EQ(ret, off);
407 }
408
409 TEST_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(pkt, 1024);
417 ret = write(self->fd, pkt, off);
418 ASSERT_EQ(ret, off);
419 }
420
421 TEST_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(pkt, 1024);
429 ret = write(self->fd, pkt, off);
430 ASSERT_EQ(ret, -1);
431 ASSERT_EQ(errno, EINVAL);
432 }
433
434 TEST_HARNESS_MAIN
435
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