xref: /openbmc/qemu/net/tap-bsd.c (revision ebe15582) 
1 /*
2  * QEMU System Emulator
3  *
4  * Copyright (c) 2003-2008 Fabrice Bellard
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 
25 #include "qemu/osdep.h"
26 #include "qemu-common.h"
27 #include "qapi/error.h"
28 #include "tap_int.h"
29 #include "qemu/cutils.h"
30 #include "qemu/error-report.h"
31 
32 #if defined(__NetBSD__) || defined(__FreeBSD__)
33 #include <sys/ioctl.h>
34 #include <net/if.h>
35 #include <net/if_tap.h>
36 #endif
37 
38 #if defined(__OpenBSD__)
39 #include <sys/param.h>
40 #endif
41 
42 #ifndef __FreeBSD__
43 int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
44              int vnet_hdr_required, int mq_required, Error **errp)
45 {
46     int fd;
47 #ifdef TAPGIFNAME
48     struct ifreq ifr;
49 #else
50     char *dev;
51     struct stat s;
52 #endif
53 
54     /* if no ifname is given, always start the search from tap0/tun0. */
55     int i;
56     char dname[100];
57 
58     for (i = 0; i < 10; i++) {
59         if (*ifname) {
60             snprintf(dname, sizeof dname, "/dev/%s", ifname);
61         } else {
62 #if defined(__OpenBSD__) && OpenBSD < 201605
63             snprintf(dname, sizeof dname, "/dev/tun%d", i);
64 #else
65             snprintf(dname, sizeof dname, "/dev/tap%d", i);
66 #endif
67         }
68         TFR(fd = open(dname, O_RDWR));
69         if (fd >= 0) {
70             break;
71         }
72         else if (errno == ENXIO || errno == ENOENT) {
73             break;
74         }
75         if (*ifname) {
76             break;
77         }
78     }
79     if (fd < 0) {
80         error_setg_errno(errp, errno, "could not open %s", dname);
81         return -1;
82     }
83 
84 #ifdef TAPGIFNAME
85     if (ioctl(fd, TAPGIFNAME, (void *)&ifr) < 0) {
86         error_setg_errno(errp, errno, "could not get tap name");
87         return -1;
88     }
89     pstrcpy(ifname, ifname_size, ifr.ifr_name);
90 #else
91     if (fstat(fd, &s) < 0) {
92         error_setg_errno(errp, errno, "could not stat %s", dname);
93         return -1;
94     }
95     dev = devname(s.st_rdev, S_IFCHR);
96     pstrcpy(ifname, ifname_size, dev);
97 #endif
98 
99     if (*vnet_hdr) {
100         /* BSD doesn't have IFF_VNET_HDR */
101         *vnet_hdr = 0;
102 
103         if (vnet_hdr_required && !*vnet_hdr) {
104             error_setg(errp, "vnet_hdr=1 requested, but no kernel "
105                        "support for IFF_VNET_HDR available");
106             close(fd);
107             return -1;
108         }
109     }
110     fcntl(fd, F_SETFL, O_NONBLOCK);
111     return fd;
112 }
113 
114 #else /* __FreeBSD__ */
115 
116 #define PATH_NET_TAP "/dev/tap"
117 
118 static int tap_open_clone(char *ifname, int ifname_size, Error **errp)
119 {
120     int fd, s, ret;
121     struct ifreq ifr;
122 
123     TFR(fd = open(PATH_NET_TAP, O_RDWR));
124     if (fd < 0) {
125         error_setg_errno(errp, errno, "could not open %s", PATH_NET_TAP);
126         return -1;
127     }
128 
129     memset(&ifr, 0, sizeof(ifr));
130 
131     ret = ioctl(fd, TAPGIFNAME, (void *)&ifr);
132     if (ret < 0) {
133         error_setg_errno(errp, errno, "could not get tap interface name");
134         close(fd);
135         return -1;
136     }
137 
138     if (ifname[0] != '\0') {
139         /* User requested the interface to have a specific name */
140         s = socket(AF_LOCAL, SOCK_DGRAM, 0);
141         if (s < 0) {
142             error_setg_errno(errp, errno,
143                              "could not open socket to set interface name");
144             close(fd);
145             return -1;
146         }
147         ifr.ifr_data = ifname;
148         ret = ioctl(s, SIOCSIFNAME, (void *)&ifr);
149         close(s);
150         if (ret < 0) {
151             error_setg(errp, "could not set tap interface name");
152             close(fd);
153             return -1;
154         }
155     } else {
156         pstrcpy(ifname, ifname_size, ifr.ifr_name);
157     }
158 
159     return fd;
160 }
161 
162 int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
163              int vnet_hdr_required, int mq_required, Error **errp)
164 {
165     int fd = -1;
166 
167     /* If the specified tap device already exists just use it. */
168     if (ifname[0] != '\0') {
169         char dname[100];
170         snprintf(dname, sizeof dname, "/dev/%s", ifname);
171         TFR(fd = open(dname, O_RDWR));
172         if (fd < 0 && errno != ENOENT) {
173             error_setg_errno(errp, errno, "could not open %s", dname);
174             return -1;
175         }
176     }
177 
178     if (fd < 0) {
179         /* Tap device not specified or does not exist. */
180         if ((fd = tap_open_clone(ifname, ifname_size, errp)) < 0) {
181             return -1;
182         }
183     }
184 
185     if (*vnet_hdr) {
186         /* BSD doesn't have IFF_VNET_HDR */
187         *vnet_hdr = 0;
188 
189         if (vnet_hdr_required && !*vnet_hdr) {
190             error_setg(errp, "vnet_hdr=1 requested, but no kernel "
191                        "support for IFF_VNET_HDR available");
192             goto error;
193         }
194     }
195     if (mq_required) {
196         error_setg(errp, "mq_required requested, but no kernel support"
197                    " for IFF_MULTI_QUEUE available");
198         goto error;
199     }
200 
201     fcntl(fd, F_SETFL, O_NONBLOCK);
202     return fd;
203 
204 error:
205     close(fd);
206     return -1;
207 }
208 #endif /* __FreeBSD__ */
209 
210 void tap_set_sndbuf(int fd, const NetdevTapOptions *tap, Error **errp)
211 {
212 }
213 
214 int tap_probe_vnet_hdr(int fd)
215 {
216     return 0;
217 }
218 
219 int tap_probe_has_ufo(int fd)
220 {
221     return 0;
222 }
223 
224 int tap_probe_vnet_hdr_len(int fd, int len)
225 {
226     return 0;
227 }
228 
229 void tap_fd_set_vnet_hdr_len(int fd, int len)
230 {
231 }
232 
233 int tap_fd_set_vnet_le(int fd, int is_le)
234 {
235     return -EINVAL;
236 }
237 
238 int tap_fd_set_vnet_be(int fd, int is_be)
239 {
240     return -EINVAL;
241 }
242 
243 void tap_fd_set_offload(int fd, int csum, int tso4,
244                         int tso6, int ecn, int ufo)
245 {
246 }
247 
248 int tap_fd_enable(int fd)
249 {
250     return -1;
251 }
252 
253 int tap_fd_disable(int fd)
254 {
255     return -1;
256 }
257 
258 int tap_fd_get_ifname(int fd, char *ifname)
259 {
260     return -1;
261 }
262