xref: /freebsd/sys/compat/linux/linux_if.c (revision 497a13601fb74c264e28eff7cd3f9ac74f0f212b)
1 /*-
2  * Copyright (c) 2015 Dmitry Chagin <dchagin@FreeBSD.org>
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  */
25 
26 #include <sys/param.h>
27 #include <sys/systm.h>
28 #include <sys/kernel.h>
29 #include <sys/ctype.h>
30 #include <sys/eventhandler.h>
31 #include <sys/jail.h>
32 #include <sys/socket.h>
33 #include <sys/sysctl.h>
34 #include <net/if.h>
35 #include <net/if_dl.h>
36 #include <net/if_types.h>
37 #include <net/if_var.h>
38 #include <net/if_private.h>
39 #include <net/vnet.h>
40 
41 #include <compat/linux/linux.h>
42 #include <compat/linux/linux_common.h>
43 #include <compat/linux/linux_mib.h>
44 
45 _Static_assert(LINUX_IFNAMSIZ == IFNAMSIZ, "Linux IFNAMSIZ");
46 
47 static bool use_real_ifnames = false;
48 SYSCTL_BOOL(_compat_linux, OID_AUTO, use_real_ifnames, CTLFLAG_RWTUN,
49     &use_real_ifnames, 0,
50     "Use FreeBSD interface names instead of generating ethN aliases");
51 
52 VNET_DEFINE_STATIC(struct unrhdr *, linux_eth_unr);
53 #define	V_linux_eth_unr	VNET(linux_eth_unr)
54 
55 static eventhandler_tag ifnet_arrival_tag;
56 static eventhandler_tag ifnet_departure_tag;
57 
58 static void
59 linux_ifnet_arrival(void *arg __unused, struct ifnet *ifp)
60 {
61 	if (ifp->if_type == IFT_ETHER)
62 		ifp->if_linux_ethno = alloc_unr(V_linux_eth_unr);
63 }
64 
65 static void
66 linux_ifnet_departure(void *arg __unused, struct ifnet *ifp)
67 {
68 	if (ifp->if_type == IFT_ETHER)
69 		free_unr(V_linux_eth_unr, ifp->if_linux_ethno);
70 }
71 
72 void
73 linux_ifnet_init(void)
74 {
75 	ifnet_arrival_tag = EVENTHANDLER_REGISTER(ifnet_arrival_event,
76 	    linux_ifnet_arrival, NULL, EVENTHANDLER_PRI_FIRST);
77 	ifnet_departure_tag = EVENTHANDLER_REGISTER(ifnet_departure_event,
78 	    linux_ifnet_departure, NULL, EVENTHANDLER_PRI_LAST);
79 }
80 
81 void
82 linux_ifnet_uninit(void)
83 {
84 	EVENTHANDLER_DEREGISTER(ifnet_arrival_event, ifnet_arrival_tag);
85 	EVENTHANDLER_DEREGISTER(ifnet_departure_event, ifnet_departure_tag);
86 }
87 
88 static void
89 linux_ifnet_vnet_init(void *arg __unused)
90 {
91 	struct epoch_tracker et;
92 	struct if_iter it;
93 	if_t ifp;
94 
95 	V_linux_eth_unr = new_unrhdr(0, INT_MAX, NULL);
96 	NET_EPOCH_ENTER(et);
97 	for (ifp = if_iter_start(&it); ifp != NULL; ifp = if_iter_next(&it))
98 		linux_ifnet_arrival(NULL, ifp);
99 	NET_EPOCH_EXIT(et);
100 }
101 VNET_SYSINIT(linux_ifnet_vnet_init, SI_SUB_PROTO_IF, SI_ORDER_ANY,
102     linux_ifnet_vnet_init, NULL);
103 
104 static void
105 linux_ifnet_vnet_uninit(void *arg __unused)
106 {
107 	/*
108 	 * All cloned interfaces are already gone at this point, as well
109 	 * as interfaces that were if_vmove'd into this vnet.  However,
110 	 * if a jail has created IFT_ETHER interfaces in self, or has had
111 	 * physical Ethernet drivers attached in self, than we may have
112 	 * allocated entries in the unr(9), so clear it to avoid KASSERT.
113 	 */
114 	clear_unrhdr(V_linux_eth_unr);
115 	delete_unrhdr(V_linux_eth_unr);
116 }
117 VNET_SYSUNINIT(linux_ifnet_vnet_uninit, SI_SUB_PROTO_IF, SI_ORDER_ANY,
118     linux_ifnet_vnet_uninit, NULL);
119 
120 /*
121  * Translate a FreeBSD interface name to a Linux interface name
122  * by interface index, and return the number of bytes copied to lxname.
123  */
124 int
125 ifname_bsd_to_linux_idx(u_int idx, char *lxname, size_t len)
126 {
127 	struct epoch_tracker et;
128 	struct ifnet *ifp;
129 	int ret;
130 
131 	ret = 0;
132 	CURVNET_SET(TD_TO_VNET(curthread));
133 	NET_EPOCH_ENTER(et);
134 	ifp = ifnet_byindex(idx);
135 	if (ifp != NULL)
136 		ret = ifname_bsd_to_linux_ifp(ifp, lxname, len);
137 	NET_EPOCH_EXIT(et);
138 	CURVNET_RESTORE();
139 	return (ret);
140 }
141 
142 /*
143  * Translate a FreeBSD interface name to a Linux interface name,
144  * and return the number of bytes copied to lxname, 0 if interface
145  * not found, -1 on error.
146  */
147 int
148 ifname_bsd_to_linux_ifp(const struct ifnet *ifp, char *lxname, size_t len)
149 {
150 	/*
151 	 * Linux loopback interface name is lo (not lo0),
152 	 * we translate lo to lo0, loX to loX.
153 	 */
154 	if (ifp->if_type == IFT_LOOP &&
155 	    strncmp(ifp->if_xname, "lo0", IFNAMSIZ) == 0)
156 		return (strlcpy(lxname, "lo", len));
157 
158 	/* Short-circuit non ethernet interfaces. */
159 	if (ifp->if_type != IFT_ETHER || use_real_ifnames)
160 		return (strlcpy(lxname, ifp->if_xname, len));
161 
162 	/* Determine the (relative) unit number for ethernet interfaces. */
163 	return (snprintf(lxname, len, "eth%d", ifp->if_linux_ethno));
164 }
165 
166 /*
167  * Translate a Linux interface name to a FreeBSD interface name,
168  * and return the associated ifnet structure
169  * bsdname and lxname need to be least IFNAMSIZ bytes long, but
170  * can point to the same buffer.
171  */
172 struct ifname_linux_to_ifp_cb_s {
173 	bool		is_lo;
174 	bool		is_eth;
175 	int		unit;
176 	const char	*lxname;
177 	if_t		ifp;
178 };
179 
180 static int
181 ifname_linux_to_ifp_cb(if_t ifp, void *arg)
182 {
183 	struct ifname_linux_to_ifp_cb_s *cbs = arg;
184 
185 	NET_EPOCH_ASSERT();
186 
187 	/*
188 	 * Allow Linux programs to use FreeBSD names. Don't presume
189 	 * we never have an interface named "eth", so don't make
190 	 * the test optional based on is_eth.
191 	 */
192 	if (strncmp(if_name(ifp), cbs->lxname, LINUX_IFNAMSIZ) == 0)
193 		goto out;
194 	if (cbs->is_eth && ifp->if_type == IFT_ETHER &&
195 	    ifp->if_linux_ethno == cbs->unit)
196 		goto out;
197 	if (cbs->is_lo && ifp->if_type == IFT_LOOP)
198 		goto out;
199 	return (0);
200 
201 out:
202 	cbs->ifp = ifp;
203 	return (1);
204 }
205 
206 struct ifnet *
207 ifname_linux_to_ifp(const char *lxname)
208 {
209 	struct ifname_linux_to_ifp_cb_s arg = {
210 		.lxname = lxname,
211 	};
212 	int len;
213 	char *ep;
214 
215 	NET_EPOCH_ASSERT();
216 
217 	for (len = 0; len < LINUX_IFNAMSIZ; ++len)
218 		if (!isalpha(lxname[len]) || lxname[len] == '\0')
219 			break;
220 	if (len == 0 || len == LINUX_IFNAMSIZ)
221 		return (NULL);
222 	/*
223 	 * Linux loopback interface name is lo (not lo0),
224 	 * we translate lo to lo0, loX to loX.
225 	 */
226 	arg.is_lo = (len == 2 && strncmp(lxname, "lo", LINUX_IFNAMSIZ) == 0);
227 	arg.unit = (int)strtoul(lxname + len, &ep, 10);
228 	if ((ep == NULL || ep == lxname + len || ep >= lxname + LINUX_IFNAMSIZ) &&
229 	    arg.is_lo == 0)
230 		return (NULL);
231 	arg.is_eth = (len == 3 && strncmp(lxname, "eth", len) == 0);
232 
233 	if_foreach(ifname_linux_to_ifp_cb, &arg);
234 	return (arg.ifp);
235 }
236 
237 int
238 ifname_linux_to_bsd(struct thread *td, const char *lxname, char *bsdname)
239 {
240 	struct epoch_tracker et;
241 	struct ifnet *ifp;
242 
243 	CURVNET_SET(TD_TO_VNET(td));
244 	NET_EPOCH_ENTER(et);
245 	ifp = ifname_linux_to_ifp(lxname);
246 	if (ifp != NULL && bsdname != NULL)
247 		strlcpy(bsdname, if_name(ifp), IFNAMSIZ);
248 	NET_EPOCH_EXIT(et);
249 	CURVNET_RESTORE();
250 	return (ifp != NULL ? 0 : EINVAL);
251 }
252 
253 unsigned short
254 linux_ifflags(struct ifnet *ifp)
255 {
256 	unsigned short flags;
257 
258 	NET_EPOCH_ASSERT();
259 
260 	flags = if_getflags(ifp) | if_getdrvflags(ifp);
261 	return (bsd_to_linux_ifflags(flags));
262 }
263 
264 unsigned short
265 bsd_to_linux_ifflags(int fl)
266 {
267 	unsigned short flags = 0;
268 
269 	if (fl & IFF_UP)
270 		flags |= LINUX_IFF_UP;
271 	if (fl & IFF_BROADCAST)
272 		flags |= LINUX_IFF_BROADCAST;
273 	if (fl & IFF_DEBUG)
274 		flags |= LINUX_IFF_DEBUG;
275 	if (fl & IFF_LOOPBACK)
276 		flags |= LINUX_IFF_LOOPBACK;
277 	if (fl & IFF_POINTOPOINT)
278 		flags |= LINUX_IFF_POINTOPOINT;
279 	if (fl & IFF_DRV_RUNNING)
280 		flags |= LINUX_IFF_RUNNING;
281 	if (fl & IFF_NOARP)
282 		flags |= LINUX_IFF_NOARP;
283 	if (fl & IFF_PROMISC)
284 		flags |= LINUX_IFF_PROMISC;
285 	if (fl & IFF_ALLMULTI)
286 		flags |= LINUX_IFF_ALLMULTI;
287 	if (fl & IFF_MULTICAST)
288 		flags |= LINUX_IFF_MULTICAST;
289 	return (flags);
290 }
291 
292 static u_int
293 linux_ifhwaddr_cb(void *arg, struct ifaddr *ifa, u_int count)
294 {
295 	struct sockaddr_dl *sdl = (struct sockaddr_dl *)ifa->ifa_addr;
296 	struct l_sockaddr *lsa = arg;
297 
298 	if (count > 0)
299 		return (0);
300 	if (sdl->sdl_type != IFT_ETHER)
301 		return (0);
302 	bzero(lsa, sizeof(*lsa));
303 	lsa->sa_family = LINUX_ARPHRD_ETHER;
304 	bcopy(LLADDR(sdl), lsa->sa_data, LINUX_IFHWADDRLEN);
305 	return (1);
306 }
307 
308 int
309 linux_ifhwaddr(struct ifnet *ifp, struct l_sockaddr *lsa)
310 {
311 
312 	NET_EPOCH_ASSERT();
313 
314 	if (ifp->if_type == IFT_LOOP) {
315 		bzero(lsa, sizeof(*lsa));
316 		lsa->sa_family = LINUX_ARPHRD_LOOPBACK;
317 		return (0);
318 	}
319 	if (ifp->if_type != IFT_ETHER)
320 		return (ENOENT);
321 	if (if_foreach_addr_type(ifp, AF_LINK, linux_ifhwaddr_cb, lsa) > 0)
322 		return (0);
323 	return (ENOENT);
324 }
325